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Sample records for robust control scheme

  1. Robust Model Predictive Control Schemes for Tracking Setpoints

    Directory of Open Access Journals (Sweden)

    Vu Trieu Minh

    2010-01-01

    Full Text Available This paper briefly reviews the development of nontracking robust model predictive control (RMPC schemes for uncertain systems using linear matrix inequalities (LMIs subject to input saturated and softened state constraints. Then we develop two new tracking setpoint RMPC schemes with common Lyapunov function and with zero terminal equality subject to input saturated and softened state constraints. The novel tracking setpoint RMPC schemes are able to stabilize uncertain systems once the output setpoints lead to the violation of the state constraints. The state violation can be regulated by changing the value of the weighting factor. A brief comparative simulation study of the two tracking setpoint RMPC schemes is done via simple examples to demonstrate the ability of the softened state constraint schemes. Finally, some features of future research from this study are discussed.

  2. Robust Fallback Scheme for the Danish Automatic Voltage Control System

    DEFF Research Database (Denmark)

    Qin, Nan; Dmitrova, Evgenia; Lund, Torsten

    2015-01-01

    This paper proposes a fallback scheme for the Danish automatic voltage control system. It will be activated in case of the local station loses telecommunication to the control center and/or the local station voltage violates the acceptable operational limits. It cuts in/out switchable and tap...

  3. A Robust Control Scheme for Medium-Voltage-Level DVR Implementation

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Li, Yun Wei

    2007-01-01

    of Hinfin controller weighting function selection, inner current loop tuning, and system disturbance rejection capability is presented. Finally, the designed control scheme is extensively tested on a laboratory 10-kV MV-level DVR system with varying voltage sag (balanced and unbalanced) and loading (linear......In this paper, a robust control scheme with an outer Hinfin voltage control loop and an inner current control loop is designed and implemented on a medium-voltage (MV)-level dynamic voltage restorer (DVR) system. Through a simple selection of weighting functions, the synthesized Hinfin controller....../nonlinear load and induction motor load) conditions. It is shown that the proposed control scheme is effective in both balanced and unbalanced sag compensation and load disturbance rejection, as its robustness is explicitly specified....

  4. A Global Sliding-Mode Control Scheme with Adjustable Robustness for A Linear Variable Reluctance Motor

    Science.gov (United States)

    Lin, Jin-Yuan; Lu, Yu-Sheng; Chen, Jian-Shiang

    A novel global sliding-mode control (GSMC) scheme with adjustable robustness is presented in this article. The proposed scheme offers a switching function together with unperturbed system dynamics to weigh the contribution from SMC such that all of the closed-loop poles can be located within predefined regions to provide design flexibility, and the robustness of system can thus be adjusted. By this scheme, the maximal control effort and chattering level can be reduced according to designer's specifications directly. Since the switching function can initially be made to equal to zero, the adjustable performance during the entire response can be guaranteed, and the reaching condition is thus lifted. The efficacy of this scheme is demonstrated via successful implementation on a linear variable reluctance motor (LVRM) servo system. Both simulation and experimental studies further demonstrate its feasibility and effectiveness.

  5. A fuzzy robust control scheme for vibration suppression of a nonlinear electromagnetic-actuated flexible system

    Science.gov (United States)

    Tavakolpour-Saleh, A. R.; Haddad, M. A.

    2017-03-01

    In this paper, a novel robust vibration control scheme, namely, one degree-of-freedom fuzzy active force control (1DOF-FAFC) is applied to a nonlinear electromagnetic-actuated flexible plate system. First, the flexible plate with clamped-free-clamped-free (CFCF) boundary conditions is modeled and simulated. Then, the validity of the simulation platform is evaluated through experiment. A nonlinear electromagnetic actuator is developed and experimentally modeled through a parametric system identification scheme. Next, the obtained nonlinear model of the actuator is applied to the simulation platform and performance of the proposed control technique in suppressing unwanted vibrations is investigated via simulation. A fuzzy controller is applied to the robust 1DOF control scheme to tune the controller gain using acceleration feedback. Consequently, an intelligent self-tuning vibration control strategy based on an inexpensive acceleration sensor is proposed in the paper. Furthermore, it is demonstrated that the proposed acceleration-based control technique owns the benefits of the conventional velocity feedback controllers. Finally, an experimental rig is developed to investigate the effectiveness of the 1DOF-FAFC scheme. It is found that the first, second, and third resonant modes of the flexible system are attenuated up to 74%, 81%, and 90% respectively through which the effectiveness of the proposed control scheme is affirmed.

  6. Robust fuzzy neural network sliding mode control scheme for IPMSM drives

    Science.gov (United States)

    Leu, V. Q.; Mwasilu, F.; Choi, H. H.; Lee, J.; Jung, J. W.

    2014-07-01

    This article proposes a robust fuzzy neural network sliding mode control (FNNSMC) law for interior permanent magnet synchronous motor (IPMSM) drives. The proposed control strategy not only guarantees accurate and fast command speed tracking but also it ensures the robustness to system uncertainties and sudden speed and load changes. The proposed speed controller encompasses three control terms: a decoupling control term which compensates for nonlinear coupling factors using nominal parameters, a fuzzy neural network (FNN) control term which approximates the ideal control components and a sliding mode control (SMC) term which is proposed to compensate for the errors of that approximation. Next, an online FNN training methodology, which is developed using the Lyapunov stability theorem and the gradient descent method, is proposed to enhance the learning capability of the FNN. Moreover, the maximum torque per ampere (MTPA) control is incorporated to maximise the torque generation in the constant torque region and increase the efficiency of the IPMSM drives. To verify the effectiveness of the proposed robust FNNSMC, simulations and experiments are performed by using MATLAB/Simulink platform and a TI TMS320F28335 DSP on a prototype IPMSM drive setup, respectively. Finally, the simulated and experimental results indicate that the proposed design scheme can achieve much better control performances (e.g. more rapid transient response and smaller steady-state error) when compared to the conventional SMC method, especially in the case that there exist system uncertainties.

  7. Self-Tuning Control Scheme Based on the Robustness σ-Modification Approach

    Directory of Open Access Journals (Sweden)

    Nabiha Touijer

    2017-01-01

    Full Text Available This paper deals with the self-tuning control problem of linear systems described by autoregressive exogenous (ARX mathematical models in the presence of unmodelled dynamics. An explicit scheme of control is described, which we use a recursive algorithm on the basis of the robustness σ-modification approach to estimate the parameters of the system, to solve the problem of regulation tracking of the system. This approach was designed with the assumptions that the norm of the vector of the parameters is well-known. A new quadratic criterion is proposed to develop a modified recursive least squares (M-RLS algorithm with σ-modification. The stability condition of the proposed estimation scheme is proved using the concepts of the small gain theorem. The effectiveness and reliability of the proposed M-RLS algorithm are shown by an illustrative simulation example. The effectiveness of the described explicit self-tuning control scheme is demonstrated by simulation results of the cruise control system for a vehicle.

  8. Definition of a Robust Supervisory Control Scheme for Sodium-Cooled Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ponciroli, R.; Passerini, S.; Vilim, R. B.

    2016-04-17

    In this work, an innovative control approach for metal-fueled Sodium-cooled Fast Reactors is proposed. With respect to the classical approach adopted for base-load Nuclear Power Plants, an alternative control strategy for operating the reactor at different power levels by respecting the system physical constraints is presented. In order to achieve a higher operational flexibility along with ensuring that the implemented control loops do not influence the system inherent passive safety features, a dedicated supervisory control scheme for the dynamic definition of the corresponding set-points to be supplied to the PID controllers is designed. In particular, the traditional approach based on the adoption of tabulated lookup tables for the set-point definition is found not to be robust enough when failures of the implemented SISO (Single Input Single Output) actuators occur. Therefore, a feedback algorithm based on the Reference Governor approach, which allows for the optimization of reference signals according to the system operating conditions, is proposed.

  9. Robust and fast schemes in broadband active noise and vibration control

    NARCIS (Netherlands)

    Fraanje, P.R.

    2004-01-01

    This thesis presents robust and fast active control algorithms for the suppression of broadband noise and vibration disturbances. Noise disturbances, e.g., generated by engines in airplanes and cars or by air ow, can be reduced by means of passive or active methods.

  10. Hybrid ARQ Error-Controlling Scheme for Robust and Efficient Transmission of UWB Body Area Networks

    Science.gov (United States)

    Suzuki, Haruka; Hernandez, Marco; Kohno, Ryuji

    This paper presents hybrid type-II automatic repeat request (H-ARQ) for wireless wearable body area networks (BANs) based on ultra wideband (UWB) technology. The proposed model is based on three schemes, namely, high rate optimized rate compatible punctured convolutional codes (HRO-RCPC), Reed Solomon (RS) invertible codes and their concatenation. Forward error correction (FEC) coding is combined with simple cyclic redundancy check (CRC) error detection. The performance is investigated for two channels: CM3 (on-body to on-body) and CM4 (on-body to a gateway) scenarios of the IEEE802.15.6 BAN channel models for BANs. It is shown that the improvement in performance in terms of throughput and error protection robustness is very significant. Thus, the proposed H-ARQ schemes can be employed and optimized to suit medical and non-medical applications. In particular we propose the use of FEC coding for non-medical applications as those require less stringent quality of service (QoS), while the incremental redundancy and ARQ configuration is utilized only for medical applications. Thus, higher QoS is guaranteed for medical application of BANs while allowing coexistence with non-medical applications.

  11. Robust Networked Control Scheme for Distributed Secondary Control of Islanded MicroGrids

    DEFF Research Database (Denmark)

    Shafiee, Qobad; Stefanovic, Cedomir; Dragicevic, Tomislav

    2014-01-01

    couples the communication and the control functionality, such that the transmission errors are absorbed through an averaging operation performed in each local controller, resulting in a very high reliability. Furthermore, transmissions from each DG are periodic and prescheduled broadcasts, and in this way...

  12. Robust synchronization control scheme of a population of nonlinear stochastic synthetic genetic oscillators under intrinsic and extrinsic molecular noise via quorum sensing

    Science.gov (United States)

    2012-01-01

    the help of LMI toolbox in MATLAB easily. Conclusion If the synchronization robustness criterion, i.e. the synchronization robustness ≥ intrinsic robustness + extrinsic robustness, then the stochastic coupled synthetic oscillators can be robustly synchronized in spite of intrinsic parameter fluctuation and extrinsic noise. If the synchronization robustness criterion is violated, external control scheme by adding inducer can be designed to improve synchronization robustness of coupled synthetic genetic oscillators. The investigated robust synchronization criteria and proposed external control method are useful for a population of coupled synthetic networks with emergent synchronization behavior, especially for multi-cellular, engineered networks. PMID:23101662

  13. Robust synchronization control scheme of a population of nonlinear stochastic synthetic genetic oscillators under intrinsic and extrinsic molecular noise via quorum sensing.

    Science.gov (United States)

    Chen, Bor-Sen; Hsu, Chih-Yuan

    2012-10-26

    toolbox in MATLAB easily. If the synchronization robustness criterion, i.e. the synchronization robustness ≥ intrinsic robustness + extrinsic robustness, then the stochastic coupled synthetic oscillators can be robustly synchronized in spite of intrinsic parameter fluctuation and extrinsic noise. If the synchronization robustness criterion is violated, external control scheme by adding inducer can be designed to improve synchronization robustness of coupled synthetic genetic oscillators. The investigated robust synchronization criteria and proposed external control method are useful for a population of coupled synthetic networks with emergent synchronization behavior, especially for multi-cellular, engineered networks.

  14. Robust synchronization control scheme of a population of nonlinear stochastic synthetic genetic oscillators under intrinsic and extrinsic molecular noise via quorum sensing

    Directory of Open Access Journals (Sweden)

    Chen Bor-Sen

    2012-10-01

    , which could be solved with the help of LMI toolbox in MATLAB easily. Conclusion If the synchronization robustness criterion, i.e. the synchronization robustness ≥ intrinsic robustness + extrinsic robustness, then the stochastic coupled synthetic oscillators can be robustly synchronized in spite of intrinsic parameter fluctuation and extrinsic noise. If the synchronization robustness criterion is violated, external control scheme by adding inducer can be designed to improve synchronization robustness of coupled synthetic genetic oscillators. The investigated robust synchronization criteria and proposed external control method are useful for a population of coupled synthetic networks with emergent synchronization behavior, especially for multi-cellular, engineered networks.

  15. A Blind Reversible Robust Watermarking Scheme for Relational Databases

    Directory of Open Access Journals (Sweden)

    Chin-Chen Chang

    2013-01-01

    Full Text Available Protecting the ownership and controlling the copies of digital data have become very important issues in Internet-based applications. Reversible watermark technology allows the distortion-free recovery of relational databases after the embedded watermark data are detected or verified. In this paper, we propose a new, blind, reversible, robust watermarking scheme that can be used to provide proof of ownership for the owner of a relational database. In the proposed scheme, a reversible data-embedding algorithm, which is referred to as “histogram shifting of adjacent pixel difference” (APD, is used to obtain reversibility. The proposed scheme can detect successfully 100% of the embedded watermark data, even if as much as 80% of the watermarked relational database is altered. Our extensive analysis and experimental results show that the proposed scheme is robust against a variety of data attacks, for example, alteration attacks, deletion attacks, mix-match attacks, and sorting attacks.

  16. A Highly Robust Single-Loop Current Control Scheme for Grid-Connected Inverter with an Improved LCCL Filter Configuration

    DEFF Research Database (Denmark)

    Pan, Donghua; Ruan, Xinbo; Wang, Xiongfei

    2018-01-01

    . The weighted average current control, which splits the filter capacitor into two parts (in form of an LCCL filter) and commands the current flowing between these two parts, is independent of the resonance frequency, but on the other hand, it is limited by the poor sensitivity to the grid impedance variation...... and weak stability in the grid current. These limitations are comprehensively explained in this paper and then addressed by identifying that the single-loop weighted average current control is equivalent to the dual-loop grid current control with an inherent capacitor current active damping. By tuning...... the capacitor split proportion as a second degree of freedom, an optimal damping performance that is robust to the grid impedance variation can be naturally achieved using only the inherent damping. Thus, no extra damping is required, and the single-loop structure with only one current sensing turns...

  17. Robust controllers for variable reluctance motors

    OpenAIRE

    Mohamed Zribi; Muthana T. Alrifai

    2005-01-01

    This paper investigates the control problem of variable reluctance motors (VRMs). VRMs are highly nonlinear motors; a model that takes magnetic saturation into account is adopted in this work. Two robust control schemes are developed for the speed control of a variable reluctance motor. The first control scheme guarantees the uniform ultimate boundedness of the closed loop system. The second control scheme guarantees the exponential stability of the closed loop system. Simulation results of t...

  18. Robustness of regional matching scheme over global matching scheme

    OpenAIRE

    Chen, Liang; Tokuda, Naoyuki

    2003-01-01

    The paper has established and verified the theory prevailing widely among image and pattern recognition specialists that the bottom-up indirect regional matching process is the more stable and the more robust than the global matching process against concentrated types of noise represented by clutter, outlier or occlusion in the imagery. We have demonstrated this by analyzing the effect of concentrated noise on a typical decision making process of a simplified two candidate voting model where ...

  19. A robust and secure watermarking scheme based on singular ...

    Indian Academy of Sciences (India)

    In this work, we propose a blind watermarking scheme based on the discrete wavelet transform (DWT) and singular value decomposition (SVD). Singular values (SV's) of high frequency (HH) band are used to optimize perceptual transparency and robustness constraints. Although most of the SVD-based schemes prove to ...

  20. Robust Self Tuning Controllers

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad

    1985-01-01

    The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...... has several operation modes and a detector for controlling the mode. A special self tuning controller has been developed to regulate plant with changing time delay....

  1. Robust Manufacturing Control

    CERN Document Server

    2013-01-01

    This contributed volume collects research papers, presented at the CIRP Sponsored Conference Robust Manufacturing Control: Innovative and Interdisciplinary Approaches for Global Networks (RoMaC 2012, Jacobs University, Bremen, Germany, June 18th-20th 2012). These research papers present the latest developments and new ideas focusing on robust manufacturing control for global networks. Today, Global Production Networks (i.e. the nexus of interconnected material and information flows through which products and services are manufactured, assembled and distributed) are confronted with and expected to adapt to: sudden and unpredictable large-scale changes of important parameters which are occurring more and more frequently, event propagation in networks with high degree of interconnectivity which leads to unforeseen fluctuations, and non-equilibrium states which increasingly characterize daily business. These multi-scale changes deeply influence logistic target achievement and call for robust planning and control ...

  2. The Crane Robust Control

    Directory of Open Access Journals (Sweden)

    Marek Hicar

    2004-01-01

    Full Text Available The article is about a control design for complete structure of the crane: crab, bridge and crane uplift.The most important unknown parameters for simulations are burden weight and length of hanging rope. We will use robustcontrol for crab and bridge control to ensure adaptivity for burden weight and rope length. Robust control will be designed for current control of the crab and bridge, necessary is to know the range of unknown parameters. Whole robust will be splitto subintervals and after correct identification of unknown parameters the most suitable robust controllers will be chosen.The most important condition at the crab and bridge motion is avoiding from burden swinging in the final position. Crab and bridge drive is designed by asynchronous motor fed from frequency converter. We will use crane uplift with burden weightobserver in combination for uplift, crab and bridge drive with cooperation of their parameters: burden weight, rope length and crab and bridge position. Controllers are designed by state control method. We will use preferably a disturbance observerwhich will identify burden weight as a disturbance. The system will be working in both modes at empty hook as well asat maximum load: burden uplifting and dropping down.

  3. Robust flight control of rotorcraft

    Science.gov (United States)

    Pechner, Adam Daniel

    With recent design improvement in fixed wing aircraft, there has been a considerable interest in the design of robust flight control systems to compensate for the inherent instability necessary to achieve desired performance. Such systems are designed for maximum available retention of stability and performance in the presence of significant vehicle damage or system failure. The rotorcraft industry has shown similar interest in adopting these reconfigurable flight control schemes specifically because of their ability to reject disturbance inputs and provide a significant amount of robustness for all but the most catastrophic of situations. The research summarized herein focuses on the extension of the pseudo-sliding mode control design procedure interpreted in the frequency domain. Application of the technique is employed and simulated on two well known helicopters, a simplified model of a hovering Sikorsky S-61 and the military's Black Hawk UH-60A also produced by Sikorsky. The Sikorsky helicopter model details are readily available and was chosen because it can be limited to pitch and roll motion reducing the number of degrees of freedom and yet contains two degrees of freedom, which is the minimum requirement in proving the validity of the pseudo-sliding control technique. The full order model of a hovering Black Hawk system was included both as a comparison to the S-61 helicopter design system and as a means to demonstrate the scaleability and effectiveness of the control technique on sophisticated systems where design robustness is of critical concern.

  4. A Robust Trust Establishment Scheme for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Farruh Ishmanov

    2015-03-01

    Full Text Available Security techniques like cryptography and authentication can fail to protect a network once a node is compromised. Hence, trust establishment continuously monitors and evaluates node behavior to detect malicious and compromised nodes. However, just like other security schemes, trust establishment is also vulnerable to attack. Moreover, malicious nodes might misbehave intelligently to trick trust establishment schemes. Unfortunately, attack-resistance and robustness issues with trust establishment schemes have not received much attention from the research community. Considering the vulnerability of trust establishment to different attacks and the unique features of sensor nodes in wireless sensor networks, we propose a lightweight and robust trust establishment scheme. The proposed trust scheme is lightweight thanks to a simple trust estimation method. The comprehensiveness and flexibility of the proposed trust estimation scheme make it robust against different types of attack and misbehavior. Performance evaluation under different types of misbehavior and on-off attacks shows that the detection rate of the proposed trust mechanism is higher and more stable compared to other trust mechanisms.

  5. A robust cloud access scheme with mutual authentication

    Directory of Open Access Journals (Sweden)

    Chen Chin-Ling

    2016-01-01

    Full Text Available Due to the progress of network technology, we can access some information through remote servers, and we also can save and access lots of personal data in remote servers. Therefore, to protect these data and resist unauthorized access is an important issue. Some researchers proposed authentication scheme, but there still exist some security weaknesses. This article is based on the concept of HDFS (Hadoop Distributed File System, and offers a robust authentication scheme. The proposed scheme achieves mutual authentication, prevents re-play attack, solves asynchronous issue, and prevents offline password guessing attack.

  6. Robust controllers for variable reluctance motors

    Directory of Open Access Journals (Sweden)

    Zribi Mohamed

    2005-01-01

    Full Text Available This paper investigates the control problem of variable reluctance motors (VRMs. VRMs are highly nonlinear motors; a model that takes magnetic saturation into account is adopted in this work. Two robust control schemes are developed for the speed control of a variable reluctance motor. The first control scheme guarantees the uniform ultimate boundedness of the closed loop system. The second control scheme guarantees the exponential stability of the closed loop system. Simulation results of the proposed controllers are presented to illustrate the theoretical developments. The simulations indicate that the proposed controllers work well, and they are robust to changes in the parameters of the motor and to changes in the load.

  7. Performance Evaluation and Robustness Testing of Advanced Oscilloscope Triggering Schemes

    Directory of Open Access Journals (Sweden)

    Shakeb A. KHAN

    2010-01-01

    Full Text Available In this paper, performance and robustness of two advanced oscilloscope triggering schemes is evaluated. The problem of time period measurement of complex waveforms can be solved using the algorithms, which utilize the associative memory network based weighted hamming distance (Whd and autocorrelation based techniques. Robustness of both the advanced techniques, are then evaluated by simulated addition of random noise of different levels to complex test signals waveforms, and minimum value of Whd (Whd min and peak value of coefficient of correlation(COCmax are computed over 10000 cycles of the selected test waveforms. The distance between mean value of second lowest value of Whd and Whd min and distance between second highest value of coefficient of correlation (COC and COC max are used as parameters to analyze the robustness of considered techniques. From the results, it is found that both the techniques are capable of producing trigger pulses efficiently; but correlation based technique is found to be better from robustness point of view.

  8. A Robust Weak Taylor Approximation Scheme for Solutions of Jump-Diffusion Stochastic Delay Differential Equations

    Directory of Open Access Journals (Sweden)

    Yanli Zhou

    2013-01-01

    Full Text Available Stochastic delay differential equations with jumps have a wide range of applications, particularly, in mathematical finance. Solution of the underlying initial value problems is important for the understanding and control of many phenomena and systems in the real world. In this paper, we construct a robust Taylor approximation scheme and then examine the convergence of the method in a weak sense. A convergence theorem for the scheme is established and proved. Our analysis and numerical examples show that the proposed scheme of high order is effective and efficient for Monte Carlo simulations for jump-diffusion stochastic delay differential equations.

  9. System Identification and Robust Control

    DEFF Research Database (Denmark)

    Tøffner-Clausen, S.

    The main purpose of this work is to develop a coherent system identification based robust control design methodology by combining recent results from system identification and robust control. In order to accomplish this task new theoretical results will be given in both fields. Firstly, however......, an introduction to modern robust control design analysis and synthesis will be given. It will be shown how the classical frequency domain techniques can be extended to multivariable systems using the singular value decomposition. An introduction to norms and spaces frequently used in modern control theory......, a non-trivial problem which to some extent has been neglected by the theoreticians of robust control. An uncertainty specification has simply been assumed given. One way of obtaining a perturbation model is by physical modelling. Application if the fundamental laws of thermodynamics, mechanics, physics...

  10. Advances in robust fractional control

    CERN Document Server

    Padula, Fabrizio

    2015-01-01

    This monograph presents design methodologies for (robust) fractional control systems. It shows the reader how to take advantage of the superior flexibility of fractional control systems compared with integer-order systems in achieving more challenging control requirements. There is a high degree of current interest in fractional systems and fractional control arising from both academia and industry and readers from both milieux are catered to in the text. Different design approaches having in common a trade-off between robustness and performance of the control system are considered explicitly. The text generalizes methodologies, techniques and theoretical results that have been successfully applied in classical (integer) control to the fractional case. The first part of Advances in Robust Fractional Control is the more industrially-oriented. It focuses on the design of fractional controllers for integer processes. In particular, it considers fractional-order proportional-integral-derivative controllers, becau...

  11. Robust Flight Controllers.

    Science.gov (United States)

    1983-12-01

    Institute of Technology, Wright-Patterson Air force Base, Ohio, December, 1982. 31. Roskam , J. Airplane Flight Dynamics and Automatic Flight Controls...Lawrence, Kansas: Roskam Aviation and Engineering, 1979. 171 " APPENDIX A: Generic Controller Format Al. Introduction In Chapter II, the idea of a

  12. Attractive ellipsoids in robust control

    CERN Document Server

    Poznyak, Alexander; Azhmyakov, Vadim

    2014-01-01

    This monograph introduces a newly developed robust-control design technique for a wide class of continuous-time dynamical systems called the “attractive ellipsoid method.” Along with a coherent introduction to the proposed control design and related topics, the monograph studies nonlinear affine control systems in the presence of uncertainty and presents a constructive and easily implementable control strategy that guarantees certain stability properties. The authors discuss linear-style feedback control synthesis in the context of the above-mentioned systems. The development and physical implementation of high-performance robust-feedback controllers that work in the absence of complete information is addressed, with numerous examples to illustrate how to apply the attractive ellipsoid method to mechanical and electromechanical systems. While theorems are proved systematically, the emphasis is on understanding and applying the theory to real-world situations. Attractive Ellipsoids in Robust Control will a...

  13. Robust control design with MATLAB

    CERN Document Server

    Gu, Da-Wei; Konstantinov, Mihail M

    2013-01-01

    Robust Control Design with MATLAB® (second edition) helps the student to learn how to use well-developed advanced robust control design methods in practical cases. To this end, several realistic control design examples from teaching-laboratory experiments, such as a two-wheeled, self-balancing robot, to complex systems like a flexible-link manipulator are given detailed presentation. All of these exercises are conducted using MATLAB® Robust Control Toolbox 3, Control System Toolbox and Simulink®. By sharing their experiences in industrial cases with minimum recourse to complicated theories and formulae, the authors convey essential ideas and useful insights into robust industrial control systems design using major H-infinity optimization and related methods allowing readers quickly to move on with their own challenges. The hands-on tutorial style of this text rests on an abundance of examples and features for the second edition: ·        rewritten and simplified presentation of theoretical and meth...

  14. Robust power system frequency control

    CERN Document Server

    Bevrani, Hassan

    2014-01-01

    This updated edition of the industry standard reference on power system frequency control provides practical, systematic and flexible algorithms for regulating load frequency, offering new solutions to the technical challenges introduced by the escalating role of distributed generation and renewable energy sources in smart electric grids. The author emphasizes the physical constraints and practical engineering issues related to frequency in a deregulated environment, while fostering a conceptual understanding of frequency regulation and robust control techniques. The resulting control strategi

  15. A robust Xbar control chart

    NARCIS (Netherlands)

    Schoonhoven, M.; Does, R.J.M.M.

    2013-01-01

    This article studies alternative standard deviation estimators that serve as a basis to determine the control chart limits used for real-time process monitoring (phase II). Several existing (robust) estimation methods are considered. In addition, we propose a new estimation method based on a phase I

  16. Methods for robust PID control

    OpenAIRE

    Bajcinca, Naim

    2013-01-01

    A comprehensive theory for robust PID control in continuous-time and discrete-time domain is reviewed in this paper. For a given finite set of linear time invariant plants, algorithms for fast computation of robustly stabilizing regions in the ($k_P, k_I, k_D$)-parameter space are introduced. The main impetus is given by the fact that non-convex stable regions in the PID parameter space can be built up by convex polygonal slices. A simple and an elegant theory evolved in the last few years up...

  17. Robust control charts in statistical process control

    OpenAIRE

    Nazir, H.Z.

    2014-01-01

    The presence of outliers and contaminations in the output of the process highly affects the performance of the design structures of commonly used control charts and hence makes them of less practical use. One of the solutions to deal with this problem is to use control charts which are robust against violations of the basic assumptions, like normality. The effect of using robust or other alternative estimators has not been investigated thoroughly in perspective of control charting literature....

  18. Cryptanalysis and Improvement of the Robust User Authentication Scheme for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yung-Cheng Lee

    2012-10-01

    Full Text Available Wireless sensor networks are widely used in industrial process control, human health care, environmental control, vehicular tracking and battlefield surveillance, etc. A wireless sensor network consists of lots of sensor nodes and a gateway node. The sensor node usually communicates with the gateway node and users over an ad hoc wireless network. However, due to the open environments, the wireless sensor networks are vulnerable to variety of security threats. Thus, it is a critical issue to adopt a suitable authentication mechanism for wireless sensor networks to enhance security. In 2009, Vaidya et al. proposed a robust user authentication schemes for wireless sensor networks. In this article, we will show that their scheme is vulnerable to the guessing attack and the impersonation attack. Since it needs a secure channel for communications in password changing phase, their scheme is also inconvenient and expensive for users to update passwords. We also propose an improved scheme to remedy the flaws. The improved scheme withstands the replay attack and off-line guessing attack, and the users can freely update their passwords via public channels.

  19. Robust control charts in statistical process control

    NARCIS (Netherlands)

    Nazir, H.Z.

    2014-01-01

    The presence of outliers and contaminations in the output of the process highly affects the performance of the design structures of commonly used control charts and hence makes them of less practical use. One of the solutions to deal with this problem is to use control charts which are robust

  20. Robust sliding-mode control of a MEMS optical switch

    Energy Technology Data Exchange (ETDEWEB)

    Ebrahimi, Behrouz; Bahrami, Mohsen [Mechanical Engineering Department, Amirkabir University of Technology, 434 Hafez Ave., Tehran 15, Iran Aerospace Research Institute, Tehran (Iran, Islamic Republic of)

    2006-04-01

    Over the last few years interests have emerged for application of MEMS in telecommunications. The use of MEMS for optical switching has turned to be the most attractive since this application could revolutionize fiber optic telecommunications. In this paper a robust control strategy based on sliding-mode control theory is developed for a MEMS optical switch, considering electrical, mechanical, and optical models. Sliding-mode control enables compact realization of a robust controller tolerant of device characteristics variation, non-linearties, and types of inherent instabilities. Robustness of proposed control scheme against disturbances is proved by Lyapunov second method and demonstrated through simulations. In addition, the presented control scheme is simple to implement in practical application.

  1. Hierarchical Robust and Adaptive Nonlinear Control Design

    National Research Council Canada - National Science Library

    Haddad, Wassim

    2003-01-01

    The authors proposed the development of a general multiechelon hierarchical nonlinear switching control design framework that minimizes control law complexity subject to the achievement of control law robustness...

  2. Advanced neural network-based computational schemes for robust fault diagnosis

    CERN Document Server

    Mrugalski, Marcin

    2014-01-01

    The present book is devoted to problems of adaptation of artificial neural networks to robust fault diagnosis schemes. It presents neural networks-based modelling and estimation techniques used for designing robust fault diagnosis schemes for non-linear dynamic systems. A part of the book focuses on fundamental issues such as architectures of dynamic neural networks, methods for designing of neural networks and fault diagnosis schemes as well as the importance of robustness. The book is of a tutorial value and can be perceived as a good starting point for the new-comers to this field. The book is also devoted to advanced schemes of description of neural model uncertainty. In particular, the methods of computation of neural networks uncertainty with robust parameter estimation are presented. Moreover, a novel approach for system identification with the state-space GMDH neural network is delivered. All the concepts described in this book are illustrated by both simple academic illustrative examples and practica...

  3. PID control with robust disturbance feedback control

    DEFF Research Database (Denmark)

    Kawai, Fukiko; Vinther, Kasper; Andersen, Palle

    2015-01-01

    Disturbance Feedback Control (DFC) is a technique, originally proposed by Fuji Electric, for augmenting existing control systems with an extra feedback for attenuation of disturbances and model errors. In this work, we analyze the robustness and performance of a PID-based control system with DFC...... and performance (if such gains exist). Finally, two different simulation case studies are evaluated and compared. Our numerical studies indicate that better performance can be achieved with the proposed method compared with a conservatively tuned PID controller and comparable performance can be achieved when...... compared with an H-infinity controller....

  4. Kinematically Optimal Robust Control of Redundant Manipulators

    Science.gov (United States)

    Galicki, M.

    2017-12-01

    This work deals with the problem of the robust optimal task space trajectory tracking subject to finite-time convergence. Kinematic and dynamic equations of a redundant manipulator are assumed to be uncertain. Moreover, globally unbounded disturbances are allowed to act on the manipulator when tracking the trajectory by the endeffector. Furthermore, the movement is to be accomplished in such a way as to minimize both the manipulator torques and their oscillations thus eliminating the potential robot vibrations. Based on suitably defined task space non-singular terminal sliding vector variable and the Lyapunov stability theory, we derive a class of chattering-free robust kinematically optimal controllers, based on the estimation of transpose Jacobian, which seem to be effective in counteracting both uncertain kinematics and dynamics, unbounded disturbances and (possible) kinematic and/or algorithmic singularities met on the robot trajectory. The numerical simulations carried out for a redundant manipulator of a SCARA type consisting of the three revolute kinematic pairs and operating in a two-dimensional task space, illustrate performance of the proposed controllers as well as comparisons with other well known control schemes.

  5. A robust anonymous biometric-based authenticated key agreement scheme for multi-server environments.

    Science.gov (United States)

    Guo, Hua; Wang, Pei; Zhang, Xiyong; Huang, Yuanfei; Ma, Fangchao

    2017-01-01

    In order to improve the security in remote authentication systems, numerous biometric-based authentication schemes using smart cards have been proposed. Recently, Moon et al. presented an authentication scheme to remedy the flaws of Lu et al.'s scheme, and claimed that their improved protocol supports the required security properties. Unfortunately, we found that Moon et al.'s scheme still has weaknesses. In this paper, we show that Moon et al.'s scheme is vulnerable to insider attack, server spoofing attack, user impersonation attack and guessing attack. Furthermore, we propose a robust anonymous multi-server authentication scheme using public key encryption to remove the aforementioned problems. From the subsequent formal and informal security analysis, we demonstrate that our proposed scheme provides strong mutual authentication and satisfies the desirable security requirements. The functional and performance analysis shows that the improved scheme has the best secure functionality and is computational efficient.

  6. A robust anonymous biometric-based authenticated key agreement scheme for multi-server environments

    Science.gov (United States)

    Huang, Yuanfei; Ma, Fangchao

    2017-01-01

    In order to improve the security in remote authentication systems, numerous biometric-based authentication schemes using smart cards have been proposed. Recently, Moon et al. presented an authentication scheme to remedy the flaws of Lu et al.’s scheme, and claimed that their improved protocol supports the required security properties. Unfortunately, we found that Moon et al.’s scheme still has weaknesses. In this paper, we show that Moon et al.’s scheme is vulnerable to insider attack, server spoofing attack, user impersonation attack and guessing attack. Furthermore, we propose a robust anonymous multi-server authentication scheme using public key encryption to remove the aforementioned problems. From the subsequent formal and informal security analysis, we demonstrate that our proposed scheme provides strong mutual authentication and satisfies the desirable security requirements. The functional and performance analysis shows that the improved scheme has the best secure functionality and is computational efficient. PMID:29121050

  7. Robust adaptive control of MEMS triaxial gyroscope using fuzzy compensator.

    Science.gov (United States)

    Fei, Juntao; Zhou, Jian

    2012-12-01

    In this paper, a robust adaptive control strategy using a fuzzy compensator for MEMS triaxial gyroscope, which has system nonlinearities, including model uncertainties and external disturbances, is proposed. A fuzzy logic controller that could compensate for the model uncertainties and external disturbances is incorporated into the adaptive control scheme in the Lyapunov framework. The proposed adaptive fuzzy controller can guarantee the convergence and asymptotical stability of the closed-loop system. The proposed adaptive fuzzy control strategy does not depend on accurate mathematical models, which simplifies the design procedure. The innovative development of intelligent control methods incorporated with conventional control for the MEMS gyroscope is derived with the strict theoretical proof of the Lyapunov stability. Numerical simulations are investigated to verify the effectiveness of the proposed adaptive fuzzy control scheme and demonstrate the satisfactory tracking performance and robustness against model uncertainties and external disturbances compared with conventional adaptive control method.

  8. Controlling the Size of Autocorrelation Robust Tests

    OpenAIRE

    Pötscher, Benedikt M.; Preinerstorfer, David

    2016-01-01

    Autocorrelation robust tests are notorious for suffering from size distortions and power problems. We investigate under which conditions the size of autocorrelation robust tests can be controlled by an appropriate choice of critical value.

  9. A robust anonymous biometric-based remote user authentication scheme using smart cards

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Das

    2015-04-01

    Full Text Available Several biometric-based remote user authentication schemes using smart cards have been proposed in the literature in order to improve the security weaknesses in user authentication system. In 2012, An proposed an enhanced biometric-based remote user authentication scheme using smart cards. It was claimed that the proposed scheme is secure against the user impersonation attack, the server masquerading attack, the password guessing attack, and the insider attack and provides mutual authentication between the user and the server. In this paper, we first analyze the security of An’s scheme and we show that this scheme has three serious security flaws in the design of the scheme: (i flaw in user’s biometric verification during the login phase, (ii flaw in user’s password verification during the login and authentication phases, and (iii flaw in user’s password change locally at any time by the user. Due to these security flaws, An’s scheme cannot support mutual authentication between the user and the server. Further, we show that An’s scheme cannot prevent insider attack. In order to remedy the security weaknesses found in An’s scheme, we propose a new robust and secure anonymous biometric-based remote user authentication scheme using smart cards. Through the informal and formal security analysis, we show that our scheme is secure against all possible known attacks including the attacks found in An’s scheme. The simulation results of our scheme using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications tool ensure that our scheme is secure against passive and active attacks. In addition, our scheme is also comparable in terms of the communication and computational overheads with An’s scheme and other related existing schemes. As a result, our scheme is more appropriate for practical applications compared to other approaches.

  10. Robust second-order scheme for multi-phase flow computations

    Science.gov (United States)

    Shahbazi, Khosro

    2017-06-01

    A robust high-order scheme for the multi-phase flow computations featuring jumps and discontinuities due to shock waves and phase interfaces is presented. The scheme is based on high-order weighted-essentially non-oscillatory (WENO) finite volume schemes and high-order limiters to ensure the maximum principle or positivity of the various field variables including the density, pressure, and order parameters identifying each phase. The two-phase flow model considered besides the Euler equations of gas dynamics consists of advection of two parameters of the stiffened-gas equation of states, characterizing each phase. The design of the high-order limiter is guided by the findings of Zhang and Shu (2011) [36], and is based on limiting the quadrature values of the density, pressure and order parameters reconstructed using a high-order WENO scheme. The proof of positivity-preserving and accuracy is given, and the convergence and the robustness of the scheme are illustrated using the smooth isentropic vortex problem with very small density and pressure. The effectiveness and robustness of the scheme in computing the challenging problem of shock wave interaction with a cluster of tightly packed air or helium bubbles placed in a body of liquid water is also demonstrated. The superior performance of the high-order schemes over the first-order Lax-Friedrichs scheme for computations of shock-bubble interaction is also shown. The scheme is implemented in two-dimensional space on parallel computers using message passing interface (MPI). The proposed scheme with limiter features approximately 50% higher number of inter-processor message communications compared to the corresponding scheme without limiter, but with only 10% higher total CPU time. The scheme is provably second-order accurate in regions requiring positivity enforcement and higher order in the rest of domain.

  11. Robust adaptive control for Unmanned Aerial Vehicles

    Science.gov (United States)

    Kahveci, Nazli E.

    anti-windup compensation. Our analysis on the indirect adaptive scheme reveals that the perturbation terms due to parameter errors do not cause any unbounded signals in the closed-loop. The stability of the adaptive system is established, and the properties of the proposed control scheme are demonstrated through simulations on a UAV model with input magnitude saturation constraints. The robust adaptive control design is further developed to extend our results to rate-saturated systems.

  12. A robust WENO scheme for nonlinear waves in a moving reference frame

    DEFF Research Database (Denmark)

    Kontos, Stavros; Bingham, Harry B.; Lindberg, Ole

    2016-01-01

    For robust nonlinear wave simulation in a moving reference frame, we recast the free surface problem in Hamilton-Jacobi form and propose a Weighted Essentially Non-Oscillatory (WENO) scheme to automatically handle the upwinding of the convective term. A new automatic procedure for deriving...... the linear WENO weights based on a Taylor series expansion is introduced. A simplified smoothness indicator is proposed and is shown to perform well. The scheme is combined with high-order explicit Runge-Kutta time integration and a dissipative Lax-Friedrichs-type flux to solve for nonlinear wave propagation...... in a moving frame of reference. The WENO scheme is robust and less dissipative than the equivalent order upwind-biased finite difference scheme for all ratios of frame of reference to wave propagation speed tested. This provides the basis for solving general nonlinear wave-structure interaction problems...

  13. Robust Tracking Control for Constrained Robots

    OpenAIRE

    Mehdi, Haifa; Boubaker, Olfa

    2014-01-01

    In this paper, a novel robust tracking control law is proposed for constrained robots under unknown stiffness environment. The stability and the robustness of the controller are proved using a Lyapunov-based approach where the relationship between the error dynamics of the robotic system and its energy is investigated. Finally, a 3DOF constrained robotic arm is used to prove the stability, the robustness and the safety of the proposed approach.

  14. Anti-Windup Scheme for Practical Control of Positioning Systems

    Directory of Open Access Journals (Sweden)

    Wahyudi Tarig Faisal and Abdulgani Albagul

    2012-10-01

    Full Text Available Positioning systems generally need a good controller to achieve high accuracy, fast response and robustness. In addition, ease of controller design and simplicity of controller structure are very important for practical application.  For satisfying these requirements, nominal characteristic trajectory following controller (NCTF has been proposed as a practical point-to-point (PTP positioning control. However, the effect of actuator saturation can not be completely compensated for due to the integrator windup as the plant parameters vary. This paper presents a method to improve the NCTF controller for overcoming the problem of integrator windup using simple and classical tracking anti-windup scheme. The improved NCTF controller is evaluated through simulation using a rotary positioning system. The results show that the improved NCTF controller is adequate to compensate for the effect of integrator windup. Keywords: Positioning, point-to-point, integrator windup, compensation, controller, robustness.

  15. A Robust Control Chart for Monitoring Dispersion

    OpenAIRE

    Zhou, Maoyuan; Geng, Wei

    2013-01-01

    Most robust control charts in the literature are for monitoring process location parameters, such as mean or median, rather than process dispersion parameters. This paper develops a new robust control chart by integrating a two-sample nonparametric test into the effective change-point model. Our proposed chart is easy in computation, convenient to use, and very powerful in detecting process dispersion shifts.

  16. Robust Control Charts for Time Series Data

    NARCIS (Netherlands)

    Croux, C.; Gelper, S.; Mahieu, K.

    2010-01-01

    This article presents a control chart for time series data, based on the one-step- ahead forecast errors of the Holt-Winters forecasting method. We use robust techniques to prevent that outliers affect the estimation of the control limits of the chart. Moreover, robustness is important to maintain

  17. Designing quantum-dot cellular automata circuits using a robust one layer crossover scheme

    Directory of Open Access Journals (Sweden)

    Sara Hashemi

    2014-04-01

    Full Text Available Quantum-dot cellular automata (QCA is a novel nanotechnology which is considered as a solution to the scaling problems in complementary metal oxide semiconductor technology. In this Letter, a robust one layer crossover scheme is introduced. It uses only 90° QCA cells and works based on a proper clock assignment. The application of this new scheme is shown in designing a sample QCA circuit. Simulation results demonstrate that using this new scheme, significant improvements in terms of area and complexity can be achieved.

  18. Multimodel Robust Control for Hydraulic Turbine

    Directory of Open Access Journals (Sweden)

    Jakub Osuský

    2014-01-01

    Full Text Available The paper deals with the multimodel and robust control system design and their combination based on M-Δ structure. Controller design will be done in the frequency domain with nominal performance specified by phase margin. Hydraulic turbine model is analyzed as system with unstructured uncertainty, and robust stability condition is included in controller design. Multimodel and robust control approaches are presented in detail on hydraulic turbine model. Control design approaches are compared and used for derivation of new approaches which combine advantages of both.

  19. An active interferometer-stabilization scheme with linear phase control

    DEFF Research Database (Denmark)

    Vardhan Krishnamachari, Vishnu; Andresen, Esben Ravn; Potma, Eric Olaf

    2006-01-01

    We report a simple and robust computer-based active interferometer stabilization scheme which does not require modulation of the interfering beams and relies on an error signal which is linearly related to the optical path difference. In this setup, a non-collinearly propagating reference laser b...... beam stabilizes the interference output of the laser light propagating collinearly through the interferometer. This stabilization scheme enables adjustable phase control with 20 ms switching times in the range from 0.02π radians to 6π radians at 632.8 nm....

  20. Robust Multiobjective Controllability of Complex Neuronal Networks.

    Science.gov (United States)

    Tang, Yang; Gao, Huijun; Du, Wei; Lu, Jianquan; Vasilakos, Athanasios V; Kurths, Jurgen

    2016-01-01

    This paper addresses robust multiobjective identification of driver nodes in the neuronal network of a cat's brain, in which uncertainties in determination of driver nodes and control gains are considered. A framework for robust multiobjective controllability is proposed by introducing interval uncertainties and optimization algorithms. By appropriate definitions of robust multiobjective controllability, a robust nondominated sorting adaptive differential evolution (NSJaDE) is presented by means of the nondominated sorting mechanism and the adaptive differential evolution (JaDE). The simulation experimental results illustrate the satisfactory performance of NSJaDE for robust multiobjective controllability, in comparison with six statistical methods and two multiobjective evolutionary algorithms (MOEAs): nondominated sorting genetic algorithms II (NSGA-II) and nondominated sorting composite differential evolution. It is revealed that the existence of uncertainties in choosing driver nodes and designing control gains heavily affects the controllability of neuronal networks. We also unveil that driver nodes play a more drastic role than control gains in robust controllability. The developed NSJaDE and obtained results will shed light on the understanding of robustness in controlling realistic complex networks such as transportation networks, power grid networks, biological networks, etc.

  1. Design Robust Controller for Rotary Kiln

    Directory of Open Access Journals (Sweden)

    Omar D. Hernández-Arboleda

    2013-11-01

    Full Text Available This paper presents the design of a robust controller for a rotary kiln. The designed controller is a combination of a fractional PID and linear quadratic regulator (LQR, these are not used to control the kiln until now, in addition robustness criteria are evaluated (gain margin, phase margin, strength gain, rejecting high frequency noise and sensitivity applied to the entire model (controller-plant, obtaining good results with a frequency range of 0.020 to 90 rad/s, which contributes to the robustness of the system.

  2. Robust quantum metrological schemes based on protection of quantum Fisher information.

    Science.gov (United States)

    Lu, Xiao-Ming; Yu, Sixia; Oh, C H

    2015-06-08

    Fragile quantum features such as entanglement are employed to improve the precision of parameter estimation and as a consequence the quantum gain becomes vulnerable to noise. As an established tool to subdue noise, quantum error correction is unfortunately overprotective because the quantum enhancement can still be achieved even if the states are irrecoverably affected, provided that the quantum Fisher information, which sets the ultimate limit to the precision of metrological schemes, is preserved and attained. Here we develop a theory of robust metrological schemes that preserve the quantum Fisher information instead of the quantum states themselves against noise. After deriving a minimal set of testable conditions on this kind of robustness, we construct a family of 2t+1 qubits metrological schemes being immune to t-qubit errors after the signal sensing. In comparison, at least five qubits are required for correcting arbitrary 1-qubit errors in standard quantum error correction.

  3. A Robust H.264/AVC Video Watermarking Scheme with Drift Compensation

    Directory of Open Access Journals (Sweden)

    Xinghao Jiang

    2014-01-01

    Full Text Available A robust H.264/AVC video watermarking scheme for copyright protection with self-adaptive drift compensation is proposed. In our scheme, motion vector residuals of macroblocks with the smallest partition size are selected to hide copyright information in order to hold visual impact and distortion drift to a minimum. Drift compensation is also implemented to reduce the influence of watermark to the most extent. Besides, discrete cosine transform (DCT with energy compact property is applied to the motion vector residual group, which can ensure robustness against intentional attacks. According to the experimental results, this scheme gains excellent imperceptibility and low bit-rate increase. Malicious attacks with different quantization parameters (QPs or motion estimation algorithms can be resisted efficiently, with 80% accuracy on average after lossy compression.

  4. Modeling and robust control of wind turbine

    Science.gov (United States)

    Gilev, Bogdan

    2016-12-01

    In this paper a model of a wind turbine is evaluated, consisting of: wind speed model, mechanical and electrical model of generator and tower oscillation model. This model is linearized around of a nominal point. By using the linear model with uncertainties is synthesized a uncertain model. By using the uncertain model and robust control theory is developed a robust controller, which provide mode of stabilizing the rotor frequency and damping the tower oscillations. Finally is simulated work of nonlinear system and robust controller

  5. Cryptanalysis and Improvement of the Robust and Blind Watermarking Scheme for Dual Color Image

    Directory of Open Access Journals (Sweden)

    Hai Nan

    2015-01-01

    Full Text Available With more color images being widely used on the Internet, the research on embedding color watermark image into color host image has been receiving more attention. Recently, Su et al. have proposed a robust and blind watermarking scheme for dual color image, in which the main innovation is the using of two-level DCT. However, it has been demonstrated in this paper that the original scheme in Su’s study is not secure and can be attacked by our proposed method. In addition, some errors in the original scheme have been pointed out. Also, an improvement measure is presented to enhance the security of the original watermarking scheme. The proposed method has been confirmed by both theoretical analysis and experimental results.

  6. Adaptive Critic Nonlinear Robust Control: A Survey.

    Science.gov (United States)

    Wang, Ding; He, Haibo; Liu, Derong

    2017-10-01

    Adaptive dynamic programming (ADP) and reinforcement learning are quite relevant to each other when performing intelligent optimization. They are both regarded as promising methods involving important components of evaluation and improvement, at the background of information technology, such as artificial intelligence, big data, and deep learning. Although great progresses have been achieved and surveyed when addressing nonlinear optimal control problems, the research on robustness of ADP-based control strategies under uncertain environment has not been fully summarized. Hence, this survey reviews the recent main results of adaptive-critic-based robust control design of continuous-time nonlinear systems. The ADP-based nonlinear optimal regulation is reviewed, followed by robust stabilization of nonlinear systems with matched uncertainties, guaranteed cost control design of unmatched plants, and decentralized stabilization of interconnected systems. Additionally, further comprehensive discussions are presented, including event-based robust control design, improvement of the critic learning rule, nonlinear H∞ control design, and several notes on future perspectives. By applying the ADP-based optimal and robust control methods to a practical power system and an overhead crane plant, two typical examples are provided to verify the effectiveness of theoretical results. Overall, this survey is beneficial to promote the development of adaptive critic control methods with robustness guarantee and the construction of higher level intelligent systems.

  7. Robust control of robots fault tolerant approaches

    CERN Document Server

    Siqueira, Adriano A G; Bergerman, Marcel

    2014-01-01

    Bridging the divide between robust control theory and its application, this volume focuses on robotic manipulators and illustrates the mathematical concepts through experimental results in reproducible detail, obtained with a two-manipulator system.

  8. Robust Tracking Control for a Piezoelectric Actuator

    National Research Council Canada - National Science Library

    Salah, M; McIntyre, M; Dawson, D; Wagner, J

    2006-01-01

    In this paper, a hysteresis model-based nonlinear robust controller is developed for a piezoelectric actuator, utilizing a Lyapunov-based stability analysis, which ensures that a desired displacement...

  9. Robust Rudder Roll Damping Control

    DEFF Research Database (Denmark)

    Yang, C.

    -infinity theory is used to deal with the problem. The necessary mathematical tools and the H-Infinity theory as the basis of controller design are presented in Chapter 2 and 3. The mu synthesis and the D-K iteration are introduced in Chapter 3. The ship dynamics and modeling technology are discussed in Chapter 4......The results of a systematic research to solve a specific ship motion control problem, simultaneous roll damping and course keeping using the rudder are presented in this thesis. The fundamental knowledge a priori is that rudder roll damping is highly sensitive to the model uncertainty, therefore H......, two kinds of ship model have been obtained: linear ship model used for designing the controller and nonlinear model used for simulation. The ship model uncertainty is discussed in this chapter and so is a wave model because the ship's roll motion is caused by waves. Using an unstructured model...

  10. Robust control systems theory and case studies

    CERN Document Server

    Mackenroth, Uwe

    2004-01-01

    "Robust Control Systems" gives a self-contained introduction to modern Control Theory. It thus adds a textbook to the existing research-oriented literature on Robust Control. The author lays emphasis on the modern aspects of the design of controllers with prescribed performance and robustness properties. Different to the classical engineering approach, a rigorous mathematical treatment is essential for the full understanding and applicability of the modern methods such as H2 or H8 control or methods based on the structured singular value µ. Nevertheless, no prior knowledge of Control Theory is required as the classical fundamentals are introduced within the first few chapters. Subsequently a large part of the text provides elementary examples and industrial case studies, which are developed in full detail to show how modern methods can be applied to advanced problems. They make intensive use of MATLAB, especially the Control Systems Toolbox and the µ-Analysis and Synthesis Toolbox.

  11. Robust Adaptive Reactive Power Control for Doubly Fed Induction Generator

    Directory of Open Access Journals (Sweden)

    Huabin Wen

    2014-01-01

    Full Text Available The problem of reactive power control for mains-side inverter (MSI in doubly fed induction generator (DFIG is studied in this paper. To accommodate the modelling nonlinearities and inherent uncertainties, a novel robust adaptive control algorithm for MSI is proposed by utilizing Lyapunov theory that ensures asymptotic stability of the system under unpredictable external disturbances and significant parametric uncertainties. The distinguishing benefit of the aforementioned scheme consists in its capabilities to maintain satisfactory performance under varying operation conditions without the need for manually redesigning or reprogramming the control gains in contrast to the commonly used PI/PID control. Simulations are also built to confirm the correctness and benefits of the control scheme.

  12. Differential on-on keying: A robust non-coherent digital modulation scheme

    KAUST Repository

    Kaddoum, Georges

    2015-05-01

    A robust digital modulation scheme, called differential on-on keying (DOOK), is presented in this paper which outperforms the conventional on-off keying (OOK). In this scheme, a sinusoidal signal is transmitted during the first half of the bit duration while a replica or an inverted version of the sinusoidal signal is transmitted during the second half for logic one or logic zero, respectively. Non-coherent receiver correlates the two halves of the received signal over half bit duration to construct a decision variable. Bit error performance is analyzed over AWGN and Rayleigh fading channels and compared to the conventional OOK.

  13. An improved auto-tuning scheme for PID controllers.

    Science.gov (United States)

    Dey, Chanchal; Mudi, Rajani K

    2009-10-01

    An improved auto-tuning scheme is proposed for Ziegler-Nichols (ZN) tuned PID controllers (ZNPIDs), which usually provide excessively large overshoots, not tolerable in most of the situations, for high-order and nonlinear processes. To overcome this limitation ZNPIDs are upgraded by some easily interpretable heuristic rules through an online gain modifying factor defined on the instantaneous process states. This study is an extension of our earlier work [Mudi RK., Dey C. Lee TT. An improved auto-tuning scheme for PI controllers. ISA Trans 2008; 47: 45-52] to ZNPIDs, thereby making the scheme suitable for a wide range of processes and more generalized too. The proposed augmented ZNPID (AZNPID) is tested on various high-order linear and nonlinear dead-time processes with improved performance over ZNPID, refined ZNPID (RZNPID), and other schemes reported in the literature. Stability issues are addressed for linear processes. Robust performance of AZNPID is observed while changing its tunable parameters as well as the process dead-time. The proposed scheme is also implemented on a real time servo-based position control system.

  14. Robust lyapunov controller for uncertain systems

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2017-02-23

    Various examples of systems and methods are provided for Lyapunov control for uncertain systems. In one example, a system includes a process plant and a robust Lyapunov controller configured to control an input of the process plant. The robust Lyapunov controller includes an inner closed loop Lyapunov controller and an outer closed loop error stabilizer. In another example, a method includes monitoring a system output of a process plant; generating an estimated system control input based upon a defined output reference; generating a system control input using the estimated system control input and a compensation term; and adjusting the process plant based upon the system control input to force the system output to track the defined output reference. An inner closed loop Lyapunov controller can generate the estimated system control input and an outer closed loop error stabilizer can generate the system control input.

  15. Robust Structured Control Design via LMI Optimization

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Stoustrup, Jakob

    2011-01-01

    This paper presents a new procedure for discrete-time robust structured control design. Parameter-dependent nonconvex conditions for stabilizable and induced L2-norm performance controllers are solved by an iterative linear matrix inequalities (LMI) optimization. A wide class of controller...

  16. Robust excitation control design using sliding-mode technique for multimachine power systems

    Energy Technology Data Exchange (ETDEWEB)

    Colbia-Vega, A.; de Leon-Morales, J.; Salas-Pena, O.; Mata-Jimenez, M.T. [Mechanical and Electrical Engineering Faculty, Autonomous University of Nuevo Leon, Cd. Universitaria, 66450 San Nicolas de los Garza, N.L. (Mexico); Fridman, L. [Department of Control, Division of Electrical Engineering Faculty, National Autonomous University of Mexico, Cd. Universitaria, 04510 Mexico, D.F. (Mexico)

    2008-09-15

    An output feedback controller is proposed to enhance the transient stability of nonlinear multimachine power systems considered as a classical model with flux decay dynamics. Combining high-order sliding-mode techniques with a robust high-order sliding-mode differentiator, a robust decentralized controller is obtained. Numerical results are presented to illustrate the performance of the proposed control scheme and its robustness properties. (author)

  17. An optimal performance control scheme for a 3D crane

    Science.gov (United States)

    Maghsoudi, Mohammad Javad; Mohamed, Z.; Husain, A. R.; Tokhi, M. O.

    2016-01-01

    This paper presents an optimal performance control scheme for control of a three dimensional (3D) crane system including a Zero Vibration shaper which considers two control objectives concurrently. The control objectives are fast and accurate positioning of a trolley and minimum sway of a payload. A complete mathematical model of a lab-scaled 3D crane is simulated in Simulink. With a specific cost function the proposed controller is designed to cater both control objectives similar to a skilled operator. Simulation and experimental studies on a 3D crane show that the proposed controller has better performance as compared to a sequentially tuned PID-PID anti swing controller. The controller provides better position response with satisfactory payload sway in both rail and trolley responses. Experiments with different payloads and cable lengths show that the proposed controller is robust to changes in payload with satisfactory responses.

  18. Robust ESO Two-Degree-of-Freedom Control Design for Permanent Magnet Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Jian-Ping Wen

    2010-01-01

    Full Text Available A robust two-degree-of-freedom control scheme is proposed for permanent magnet synchronous motor (PMSM using extended state observer (ESO. The robustness is achieved based on the ESO. Parameter perturbation and external disturbances in PMSM drive system are treated as disturbance variable, and then the motion model of PMSM is transformed into an extended state model by introducing this disturbance variable. To estimate the disturbance variable, an ESO is constructed. Estimator is compensated into the control system to improve robustness and adaptability of 2DOF controller against parameter perturbation and external disturbances. The effectiveness of the proposed control scheme is demonstrated with simulation results.

  19. Two stage neural network modelling for robust model predictive control.

    Science.gov (United States)

    Patan, Krzysztof

    2017-11-02

    The paper proposes a novel robust model predictive control scheme realized by means of artificial neural networks. The neural networks are used twofold: to design the so-called fundamental model of a plant and to catch uncertainty associated with the plant model. In order to simplify the optimization process carried out within the framework of predictive control an instantaneous linearization is applied which renders it possible to define the optimization problem in the form of constrained quadratic programming. Stability of the proposed control system is also investigated by showing that a cost function is monotonically decreasing with respect to time. Derived robust model predictive control is tested and validated on the example of a pneumatic servomechanism working at different operating regimes. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Robust Control Methods for a Recycle Bioreactor

    Directory of Open Access Journals (Sweden)

    Cosmin IONETE

    2001-12-01

    Full Text Available The paper presents a robust control design strategy for bioprocesses, which are characterized by strongly nonlinear dynamics. More precisely, we present the H2 methodology in order to compute the controller for a recycle Continuous Stirred Tank Bioreactor (CSTB. We consider a general method of formulating control problem, which makes use of linear fractional transformation as introduced by Doyle (1978. The formulation makes use of the general two-port configuration of the generalized plant with a generalized controller. The H2 norm is the quadratic criterion used in optimal control as LQG. The overall control objective is to minimize the H2 norm of the transfer matrix function from the weighted exogenous inputs to the weighted controlled outputs. The advantage of H2 control technique, which uses the linearized model of the CSTB, is that it is completely automated and very flexible. Finally, we prove that the closed loop control structure has very good inner robustness.

  1. A Robust Color Image Watermarking Scheme Using Entropy and QR Decomposition

    Directory of Open Access Journals (Sweden)

    L. Laur

    2015-12-01

    Full Text Available Internet has affected our everyday life drastically. Expansive volumes of information are exchanged over the Internet consistently which causes numerous security concerns. Issues like content identification, document and image security, audience measurement, ownership, copyrights and others can be settled by using digital watermarking. In this work, robust and imperceptible non-blind color image watermarking algorithm is proposed, which benefit from the fact that watermark can be hidden in different color channel which results into further robustness of the proposed technique to attacks. Given method uses some algorithms such as entropy, discrete wavelet transform, Chirp z-transform, orthogonal-triangular decomposition and Singular value decomposition in order to embed the watermark in a color image. Many experiments are performed using well-known signal processing attacks such as histogram equalization, adding noise and compression. Experimental results show that proposed scheme is imperceptible and robust against common signal processing attacks.

  2. Robust Geometric Control of a Distillation Column

    DEFF Research Database (Denmark)

    Kymmel, Mogens; Andersen, Henrik Weisberg

    1987-01-01

    A frequency domain method, which makes it possible to adjust multivariable controllers with respect to both nominal performance and robustness, is presented. The basic idea in the approach is that the designer assigns objectives such as steady-state tracking, maximum resonance peaks, bandwidth, m...... is used to examine and improve geometric control of a binary distillation column....

  3. Robust PID Controller for a Pneumatic Actuator

    OpenAIRE

    Skarpetis Michael G.; Koumboulis Fotis N.; Panagiotakis George; Kouvakas Nikolaos D.

    2016-01-01

    In this paper the position control pneumatic actuator using a robust PID controller is presented. The parameters of the PID controller are computed using a Hurwitz invariability technique enriched with a Simulated Annealing Algorithm. The nonlinear model involves uncertain parameters due to linearization of the servo valve, variations of the initial volume of the cylinder and variation of the external load. The problem is proven to be solvable and the controller parameters are chosen to provi...

  4. Robustness of network controllability in cascading failure

    Science.gov (United States)

    Chen, Shi-Ming; Xu, Yun-Fei; Nie, Sen

    2017-04-01

    It is demonstrated that controlling complex networks in practice needs more inputs than that predicted by the structural controllability framework. Besides, considering the networks usually faces to the external or internal failure, we define parameters to evaluate the control cost and the variation of controllability after cascades, exploring the effect of number of control inputs on the controllability for random networks and scale-free networks in the process of cascading failure. For different topological networks, the results show that the robustness of controllability will be stronger through allocating different control inputs and edge capacity.

  5. Wind Turbine Control: Robust Model Based Approach

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood

    . Wind turbines are the most common wind energy conversion systems and are hoped to be able to compete economically with fossil fuel power plants in near future. However this demands better technology to reduce the price of electricity production. Control can play an essential part in this context...... wind turbine control using robust MPC. In general, robust MPC problems are very computationally demanding, however we have shown that with some approximations the resulting robust MPC problem can be specialized with reduced computational complexity. After a short introduction on wind energy and wind....... This is because, on the one hand, control methods can decrease the cost of energy by keeping the turbine close to its maximum efficiency. On the other hand, they can reduce structural fatigue and therefore increase the lifetime of the wind turbine. The power produced by a wind turbine is proportional...

  6. Dsp-based Robust Nonlinear Speed Control of PM Synchronous Motor

    Energy Technology Data Exchange (ETDEWEB)

    Baik, I.C.; Kim, K.H.; Youn, M.J. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-02-01

    A DSP-based robust nonlinear speed control of a permanent magnet synchronous motor(PMSM) is presented. A quasi-linearized and decoupled model including the influence of parameter variations and speed measurement error on the nonlinear speed control of a PMSM is derived. Based on this model, a boundary layer integral sliding mode controller to improve the robustness and performance of the nonlinear speed control of a PMSM is designed and compared with the conventional controller. To show the validity of the proposed control scheme, simulations and experimental works are carried out and compared with the conventional control scheme. (author). 17 refs., 10 figs.

  7. Robust and Adaptive Control With Aerospace Applications

    CERN Document Server

    Lavretsky, Eugene

    2013-01-01

    Robust and Adaptive Control shows the reader how to produce consistent and accurate controllers that operate in the presence of uncertainties and unforeseen events. Driven by aerospace applications the focus of the book is primarily on continuous-dynamical systems.  The text is a three-part treatment, beginning with robust and optimal linear control methods and moving on to a self-contained presentation of the design and analysis of model reference adaptive control (MRAC) for nonlinear uncertain dynamical systems. Recent extensions and modifications to MRAC design are included, as are guidelines for combining robust optimal and MRAC controllers. Features of the text include: ·         case studies that demonstrate the benefits of robust and adaptive control for piloted, autonomous and experimental aerial platforms; ·         detailed background material for each chapter to motivate theoretical developments; ·         realistic examples and simulation data illustrating key features ...

  8. Matlab as a robust control design tool

    Science.gov (United States)

    Gregory, Irene M.

    1994-01-01

    This presentation introduces Matlab as a tool used in flight control research. The example used to illustrate some of the capabilities of this software is a robust controller designed for a single stage to orbit air breathing vehicles's ascent to orbit. The global requirements of the controller are to stabilize the vehicle and follow a trajectory in the presence of atmospheric disturbances and strong dynamic coupling between airframe and propulsion.

  9. Robust Adaptive Control In Hilbert Space

    Science.gov (United States)

    Wen, John Ting-Yung; Balas, Mark J.

    1990-01-01

    Paper discusses generalization of scheme for adaptive control of finite-dimensional system to infinite-dimensional Hilbert space. Approach involves generalization of command-generator tracker (CGT) theory. Does not require reference model to be same order as that of plant, and knowledge of order of plant not needed. Suitable for application to high-order systems, main emphasis on adjustment of low-order feedback-gain matrix. Analysis particularly relevant to control of large, flexible structures.

  10. Robust H∞ Control Design of NCS

    Directory of Open Access Journals (Sweden)

    Yu ZHAO

    2014-06-01

    Full Text Available Some unknown elements always exist in the analysis process for the control systems, such as unmodeled dynamics, parametric uncertainties, change of the operating environment, model reduction and linearization approximations, etc., or external disturbance. So it is significative to study the disturbance process or the uncertain systems. The emergence and the development of the robust control theory were just in such environment, and it is becoming an important research field of the control theory and its practice applications. To address instability and jump degeneration of linear network control system with time-delay and packet dropout, and considering uncertainties of network control systems model and external disturbance, the paper presents network control systems delay- dependent stochastic stability and Linear matrix inequalities (LMI conditions by introducing Lyapunov- Krasovskii functional and relaxation matrix variable. The paper proposes the network control system delay-dependent stochastic stability and disturbance attenuation LMI conditions and robust H∞ control system perturbation attenuation performance analysis. By using simple mathematical derivation, solving two Riccati equations, we can be sub-optimal control solution. Finally, the simulation example can be found robust stability, simple and effective.

  11. A Blind Video Watermarking Scheme Robust To Frame Attacks Combined With MPEG2 Compression

    Directory of Open Access Journals (Sweden)

    C. Cruz-Ramos

    2010-12-01

    Full Text Available ABSTRACTIn this paper, we propose a robust digital video watermarking scheme with completely blind extraction process wherethe original video data, original watermark or any other information derivative of them are not required in order toretrieve the embedded watermark. The proposed algorithm embeds 2D binary visually recognizable patterns such ascompany trademarks and owner’s logotype, etc., in the DWT domain of the video frames for copyright protection.Before the embedding process, only two numerical keys are required to transform the watermark data into a noise-likepattern using the chaotic mixing method which helps to increase the security. The main advantages of the proposedscheme are its completely blind detection scheme, robustness against common video attacks, combined attacks andits low complexity implementation. The combined attacks consist of MPEG-2 compression and common video attackssuch as noise contamination, collusion attacks, frame dropping and swapping. Extensive simulation results also showthat the watermark imperceptibility and robustness outperform other previously reported methods. The extractedwatermark data from the watermarked video sequences is clear enough even after the watermarked video hadsuffered from several attacks.

  12. Robustness analysis method for orbit control

    Science.gov (United States)

    Zhang, Jingrui; Yang, Keying; Qi, Rui; Zhao, Shuge; Li, Yanyan

    2017-08-01

    Satellite orbits require periodical maintenance due to the presence of perturbations. However, random errors caused by inaccurate orbit determination and thrust implementation may lead to failure of the orbit control strategy. Therefore, it is necessary to analyze the robustness of the orbit control methods. Feasible strategies which are tolerant to errors of a certain magnitude can be developed to perform reliable orbit control for the satellite. In this paper, first, the orbital dynamic model is formulated by Gauss' form of the planetary equation using the mean orbit elements; the atmospheric drag and the Earth's non-spherical perturbations are taken into consideration in this model. Second, an impulsive control strategy employing the differential correction algorithm is developed to maintain the satellite trajectory parameters in given ranges. Finally, the robustness of the impulsive control method is analyzed through Monte Carlo simulations while taking orbit determination error and thrust error into account.

  13. Model predictive control classical, robust and stochastic

    CERN Document Server

    Kouvaritakis, Basil

    2016-01-01

    For the first time, a textbook that brings together classical predictive control with treatment of up-to-date robust and stochastic techniques. Model Predictive Control describes the development of tractable algorithms for uncertain, stochastic, constrained systems. The starting point is classical predictive control and the appropriate formulation of performance objectives and constraints to provide guarantees of closed-loop stability and performance. Moving on to robust predictive control, the text explains how similar guarantees may be obtained for cases in which the model describing the system dynamics is subject to additive disturbances and parametric uncertainties. Open- and closed-loop optimization are considered and the state of the art in computationally tractable methods based on uncertainty tubes presented for systems with additive model uncertainty. Finally, the tube framework is also applied to model predictive control problems involving hard or probabilistic constraints for the cases of multiplic...

  14. Robust Adaptive PID Control of Robot Manipulator with Bounded Disturbances

    Directory of Open Access Journals (Sweden)

    Jian Xu

    2013-01-01

    Full Text Available To solve the strong nonlinearity and coupling problems in robot manipulator control, two novel robust adaptive PID control schemes are proposed in this paper with known or unknown upper bound of the external disturbances. Invoking the two proposed controllers, the unknown bounded external disturbances can be compensated and the global asymptotical stability with respect to the manipulator positions and velocities is able to be guaranteed. As compared with the existing adaptive PD control methods, the designed control laws can enlarge the tolerable external disturbances, enhance the accuracy in finite-time trajectory tracking control, and improve the dynamic performance of the manipulator systems. The stability and convergence properties of the closed-loop system are analytically proved using Lyapunov stability theory and Barbalat’s lemma. Simulations are performed for a planner manipulator with two rotary degrees of freedom to illustrate the viability and the advantages of the proposed controllers.

  15. Automatic Synthesis of Robust and Optimal Controllers

    DEFF Research Database (Denmark)

    Cassez, Franck; Jessen, Jan Jacob; Larsen, Kim Guldstrand

    2009-01-01

    In this paper, we show how to apply recent tools for the automatic synthesis of robust and near-optimal controllers for a real industrial case study. We show how to use three different classes of models and their supporting existing tools, Uppaal-TiGA for synthesis, phaver for verification...

  16. Robust control investigations for equipment loaded panels

    DEFF Research Database (Denmark)

    Aglietti, G.S.; Langley, R.S.; Rogers, E.

    1998-01-01

    This paper develops a modelling technique for equipment load panels which directly produces (adequate) models of the underlying dynamics on which to base robust controller design/evaluations. This technique is based on the use of the Lagrange's equations of motion and the resulting models...

  17. Adaptive Tracking Control for Robots With an Interneural Computing Scheme.

    Science.gov (United States)

    Tsai, Feng-Sheng; Hsu, Sheng-Yi; Shih, Mau-Hsiang

    2017-01-24

    Adaptive tracking control of mobile robots requires the ability to follow a trajectory generated by a moving target. The conventional analysis of adaptive tracking uses energy minimization to study the convergence and robustness of the tracking error when the mobile robot follows a desired trajectory. However, in the case that the moving target generates trajectories with uncertainties, a common Lyapunov-like function for energy minimization may be extremely difficult to determine. Here, to solve the adaptive tracking problem with uncertainties, we wish to implement an interneural computing scheme in the design of a mobile robot for behavior-based navigation. The behavior-based navigation adopts an adaptive plan of behavior patterns learning from the uncertainties of the environment. The characteristic feature of the interneural computing scheme is the use of neural path pruning with rewards and punishment interacting with the environment. On this basis, the mobile robot can be exploited to change its coupling weights in paths of neural connections systematically, which can then inhibit or enhance the effect of flow elimination in the dynamics of the evolutionary neural network. Such dynamical flow translation ultimately leads to robust sensory-to-motor transformations adapting to the uncertainties of the environment. A simulation result shows that the mobile robot with the interneural computing scheme can perform fault-tolerant behavior of tracking by maintaining suitable behavior patterns at high frequency levels.

  18. Experimental Study on Intelligent Control Scheme for Fan Coil Air-Conditioning System

    Directory of Open Access Journals (Sweden)

    Yanfeng Li

    2013-01-01

    Full Text Available An intelligent control scheme for fan coil air-conditioning systems has been put forward in order to overcome the shortcomings of the traditional proportion-integral-derivative (PID control scheme. These shortcomings include the inability of anti-interference and large inertia. An intelligent control test rig of fan coil air-conditioning system has been built, and MATLAB/Simulink dynamics simulation software has been adopted to implement the intelligent control scheme. A software for data exchange has been developed to combine the intelligence control system and the building automation (BA system. Experimental tests have been conducted to investigate the effectiveness of different control schemes including the traditional PID control, fuzzy control, and fuzzy-PID control for fan coil air-conditioning system. The effects of control schemes have been compared and analyzed in robustness, static and dynamic character, and economy. The results have shown that the developed data exchange interface software can induce the intelligent control scheme of the BA system more effectively. Among the proposed control strategies, fuzzy-PID control scheme which has the advantages of both traditional PID and fuzzy schemes is the optimal control scheme for the fan coil air-conditioning system.

  19. Robust control through signal constraints with application to predictive control

    NARCIS (Netherlands)

    de Vries, R.A.J.

    2006-01-01

    This thesis presents a novel approach to robust controller design. It describes how linear constraints can be derived on the output of an arbitrary controller, that guarantee robust bounded-input/bounded-output stability and asymptotic perfect tracking of the reference when the external signals

  20. Fuzzy model based adaptive synchronization of uncertain chaotic systems: Robust tracking control approach

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Eun-Ju; Hyun, Chang-Ho; Kim, Euntai [ICS Laboratory (B723), Department of Electrical and Electronic Engineering, Yonsei University, 134, Shinchon-Dong, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Park, Mignon [ICS Laboratory (B723), Department of Electrical and Electronic Engineering, Yonsei University, 134, Shinchon-Dong, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of)], E-mail: mignpark@yonsei.ac.kr

    2009-05-11

    This Letter presents fuzzy model-based robust tracking control for the adaptive synchronization of uncertain chaotic systems. Fuzzy model and adaptive algorithm are employed to present the unknown chaotic systems. H{sup {infinity}} and sliding mode control are combined to construct a robust tracking controller. The incorporated H{sup {infinity}} controller can attenuate the external disturbance and approximation error to any prescribed level. The proposed scheme guarantees that all the variables are bounded and the tracking error is compensated.

  1. Integrated robust controller for vehicle path following

    Energy Technology Data Exchange (ETDEWEB)

    Mashadi, Behrooz; Ahmadizadeh, Pouyan, E-mail: p-ahmadizadeh@iust.ac.ir; Majidi, Majid, E-mail: m-majidi@iust.ac.ir [Iran University of Science and Technology, School of Automotive Engineering (Iran, Islamic Republic of); Mahmoodi-Kaleybar, Mehdi, E-mail: m-mahmoodi-k@iust.ac.ir [Iran University of Science and Technology, School of Mechanical Engineering (Iran, Islamic Republic of)

    2015-02-15

    The design of an integrated 4WS+DYC control system to guide a vehicle on a desired path is presented. The lateral dynamics of the path follower vehicle is formulated by considering important parameters. To reduce the effect of uncertainties in vehicle parameters, a robust controller is designed based on a μ-synthesis approach. Numerical simulations are performed using a nonlinear vehicle model in MATLAB environment in order to investigate the effectiveness of the designed controller. Results of simulations show that the controller has a profound ability to making the vehicle track the desired path in the presence of uncertainties.

  2. Effective and Robust Generalized Predictive Speed Control of Induction Motor

    Directory of Open Access Journals (Sweden)

    Patxi Alkorta

    2013-01-01

    Full Text Available This paper presents and validates a new proposal for effective speed vector control of induction motors based on linear Generalized Predictive Control (GPC law. The presented GPC-PI cascade configuration simplifies the design with regard to GPC-GPC cascade configuration, maintaining the advantages of the predictive control algorithm. The robust stability of the closed loop system is demonstrated by the poles placement method for several typical cases of uncertainties in induction motors. The controller has been tested using several simulations and experiments and has been compared with Proportional Integral Derivative (PID and Sliding Mode (SM control schemes, obtaining outstanding results in speed tracking even in the presence of parameter uncertainties, unknown load disturbance, and measurement noise in the loop signals, suggesting its use in industrial applications.

  3. ROBUST CONTROL OF WIENER SYSTEMS: APPLICATION TO A pH NEUTRALIZATION PROCESS

    OpenAIRE

    Biagiola, S. I.; O. E. Agamennoni; J. L. FIGUEROA

    2016-01-01

    Abstract In this paper, the robustness of a typical control scheme for Wiener systems is studied. These systems consist of the cascade connection of a linear time invariant system and a static nonlinearity. To control this kind of systems, several approaches were discussed in the literature. Most of these control schemes involve transformation of the measured variable as well as the setpoint, by the inverse of the nonlinear gain. The approach followed in this work uses the inverse model of th...

  4. Change Point Detection with Robust Control Chart

    Directory of Open Access Journals (Sweden)

    Ng Kooi Huat

    2011-01-01

    Full Text Available Monitoring a process over time using a control chart allows quick detection of unusual states. In phase I, some historical process data, assumed to come from an in-control process, are used to construct the control limits. In Phase II, the process is monitored for an ongoing basis using control limits from Phase I. In Phase II, observations falling outside the control limits or unusual patterns of observations signal that the process has shifted from in-control process settings. Such signals trigger a search for assignable cause and, if the cause is found, corrective action will be implemented to prevent its recurrence. The purpose of this paper is to introduce a new methodology appropriate for constructing a robust control chart when a nonnormal or a contaminated data that may arise in phase I state. Through extensive Monte Carlo simulations, we examine the behaviors and performances of the proposed MM robust control chart when there is a process shift in mean.

  5. Combined Control Scheme for Monitoring Quality Characteristics

    Directory of Open Access Journals (Sweden)

    Adekeye K.S.

    2014-07-01

    Full Text Available In the literature, the Exponentially Weighted Moving Average (EWMA and Exponentially Weighted Moving Variance (EMWV control schemes have been used separately to monitor the process average and process variability respectively. Here the two are combined and applied on simulated process with different level of variation. The control limit interval (CLI and the average run length (ARL were evaluated for the combined chart. The combined chart performed better than the two independently. Furthermore, an algorithm was developed for the two control charts and implemented on visual basic VB6.0. The obtained results show that the combined EWMA and EWMV control chart is very sensitive in detecting shift in production process and every shift in the process mean is always preceded by shift in the process variability.

  6. Robust Decentralized Nonlinear Control for a Twin Rotor MIMO System.

    Science.gov (United States)

    Belmonte, Lidia María; Morales, Rafael; Fernández-Caballero, Antonio; Somolinos, José Andrés

    2016-07-27

    This article presents the design of a novel decentralized nonlinear multivariate control scheme for an underactuated, nonlinear and multivariate laboratory helicopter denominated the twin rotor MIMO system (TRMS). The TRMS is characterized by a coupling effect between rotor dynamics and the body of the model, which is due to the action-reaction principle originated in the acceleration and deceleration of the motor-propeller groups. The proposed controller is composed of two nested loops that are utilized to achieve stabilization and precise trajectory tracking tasks for the controlled position of the generalized coordinates of the TRMS. The nonlinear internal loop is used to control the electrical dynamics of the platform, and the nonlinear external loop allows the platform to be perfectly stabilized and positioned in space. Finally, we illustrate the theoretical control developments with a set of experiments in order to verify the effectiveness of the proposed nonlinear decentralized feedback controller, in which a comparative study with other controllers is performed, illustrating the excellent performance of the proposed robust decentralized control scheme in both stabilization and trajectory tracking tasks.

  7. An Effective and Robust Decentralized Target Tracking Scheme in Wireless Camera Sensor Networks.

    Science.gov (United States)

    Fu, Pengcheng; Cheng, Yongbo; Tang, Hongying; Li, Baoqing; Pei, Jun; Yuan, Xiaobing

    2017-03-20

    In this paper, we propose an effective and robust decentralized tracking scheme based on the square root cubature information filter (SRCIF) to balance the energy consumption and tracking accuracy in wireless camera sensor networks (WCNs). More specifically, regarding the characteristics and constraints of camera nodes in WCNs, some special mechanisms are put forward and integrated in this tracking scheme. First, a decentralized tracking approach is adopted so that the tracking can be implemented energy-efficiently and steadily. Subsequently, task cluster nodes are dynamically selected by adopting a greedy on-line decision approach based on the defined contribution decision (CD) considering the limited energy of camera nodes. Additionally, we design an efficient cluster head (CH) selection mechanism that casts such selection problem as an optimization problem based on the remaining energy and distance-to-target. Finally, we also perform analysis on the target detection probability when selecting the task cluster nodes and their CH, owing to the directional sensing and observation limitations in field of view (FOV) of camera nodes in WCNs. From simulation results, the proposed tracking scheme shows an obvious improvement in balancing the energy consumption and tracking accuracy over the existing methods.

  8. An Effective and Robust Decentralized Target Tracking Scheme in Wireless Camera Sensor Networks

    Science.gov (United States)

    Fu, Pengcheng; Cheng, Yongbo; Tang, Hongying; Li, Baoqing; Pei, Jun; Yuan, Xiaobing

    2017-01-01

    In this paper, we propose an effective and robust decentralized tracking scheme based on the square root cubature information filter (SRCIF) to balance the energy consumption and tracking accuracy in wireless camera sensor networks (WCNs). More specifically, regarding the characteristics and constraints of camera nodes in WCNs, some special mechanisms are put forward and integrated in this tracking scheme. First, a decentralized tracking approach is adopted so that the tracking can be implemented energy-efficiently and steadily. Subsequently, task cluster nodes are dynamically selected by adopting a greedy on-line decision approach based on the defined contribution decision (CD) considering the limited energy of camera nodes. Additionally, we design an efficient cluster head (CH) selection mechanism that casts such selection problem as an optimization problem based on the remaining energy and distance-to-target. Finally, we also perform analysis on the target detection probability when selecting the task cluster nodes and their CH, owing to the directional sensing and observation limitations in field of view (FOV) of camera nodes in WCNs. From simulation results, the proposed tracking scheme shows an obvious improvement in balancing the energy consumption and tracking accuracy over the existing methods. PMID:28335537

  9. Robust Control Design via Linear Programming

    Science.gov (United States)

    Keel, L. H.; Bhattacharyya, S. P.

    1998-01-01

    This paper deals with the problem of synthesizing or designing a feedback controller of fixed dynamic order. The closed loop specifications considered here are given in terms of a target performance vector representing a desired set of closed loop transfer functions connecting various signals. In general these point targets are unattainable with a fixed order controller. By enlarging the target from a fixed point set to an interval set the solvability conditions with a fixed order controller are relaxed and a solution is more easily enabled. Results from the parametric robust control literature can be used to design the interval target family so that the performance deterioration is acceptable, even when plant uncertainty is present. It is shown that it is possible to devise a computationally simple linear programming approach that attempts to meet the desired closed loop specifications.

  10. Noise Robust Feature Scheme for Automatic Speech Recognition Based on Auditory Perceptual Mechanisms

    Science.gov (United States)

    Cai, Shang; Xiao, Yeming; Pan, Jielin; Zhao, Qingwei; Yan, Yonghong

    Mel Frequency Cepstral Coefficients (MFCC) are the most popular acoustic features used in automatic speech recognition (ASR), mainly because the coefficients capture the most useful information of the speech and fit well with the assumptions used in hidden Markov models. As is well known, MFCCs already employ several principles which have known counterparts in the peripheral properties of human hearing: decoupling across frequency, mel-warping of the frequency axis, log-compression of energy, etc. It is natural to introduce more mechanisms in the auditory periphery to improve the noise robustness of MFCC. In this paper, a k-nearest neighbors based frequency masking filter is proposed to reduce the audibility of spectra valleys which are sensitive to noise. Besides, Moore and Glasberg's critical band equivalent rectangular bandwidth (ERB) expression is utilized to determine the filter bandwidth. Furthermore, a new bandpass infinite impulse response (IIR) filter is proposed to imitate the temporal masking phenomenon of the human auditory system. These three auditory perceptual mechanisms are combined with the standard MFCC algorithm in order to investigate their effects on ASR performance, and a revised MFCC extraction scheme is presented. Recognition performances with the standard MFCC, RASTA perceptual linear prediction (RASTA-PLP) and the proposed feature extraction scheme are evaluated on a medium-vocabulary isolated-word recognition task and a more complex large vocabulary continuous speech recognition (LVCSR) task. Experimental results show that consistent robustness against background noise is achieved on these two tasks, and the proposed method outperforms both the standard MFCC and RASTA-PLP.

  11. Robust low-dose dynamic cerebral perfusion CT image restoration via coupled dictionary learning scheme.

    Science.gov (United States)

    Tian, Xiumei; Zeng, Dong; Zhang, Shanli; Huang, Jing; Zhang, Hua; He, Ji; Lu, Lijun; Xi, Weiwen; Ma, Jianhua; Bian, Zhaoying

    2016-11-22

    Dynamic cerebral perfusion x-ray computed tomography (PCT) imaging has been advocated to quantitatively and qualitatively assess hemodynamic parameters in the diagnosis of acute stroke or chronic cerebrovascular diseases. However, the associated radiation dose is a significant concern to patients due to its dynamic scan protocol. To address this issue, in this paper we propose an image restoration method by utilizing coupled dictionary learning (CDL) scheme to yield clinically acceptable PCT images with low-dose data acquisition. Specifically, in the present CDL scheme, the 2D background information from the average of the baseline time frames of low-dose unenhanced CT images and the 3D enhancement information from normal-dose sequential cerebral PCT images are exploited to train the dictionary atoms respectively. After getting the two trained dictionaries, we couple them to represent the desired PCT images as spatio-temporal prior in objective function construction. Finally, the low-dose dynamic cerebral PCT images are restored by using a general DL image processing. To get a robust solution, the objective function is solved by using a modified dictionary learning based image restoration algorithm. The experimental results on clinical data show that the present method can yield more accurate kinetic enhanced details and diagnostic hemodynamic parameter maps than the state-of-the-art methods.

  12. The Robust Control Mixer Module Method for Control Reconfiguration

    DEFF Research Database (Denmark)

    Yang, Z.; Blanke, M.

    1999-01-01

    into a LTI dynamical system, and furthermore multiple dynamical control mixer modules can be employed in our consideration. The H_{\\infty} control theory is used for the analysis and design of the robust control mixer modules. Finally, one practical robot arm system as benchmark is used to test the proposed...

  13. An improved robust fuzzy-PID controller with optimal fuzzy reasoning.

    Science.gov (United States)

    Li, Han-Xiong; Zhang, Lei; Cai, Kai-Yuan; Chen, Guanrong

    2005-12-01

    Many fuzzy control schemes used in industrial practice today are based on some simplified fuzzy reasoning methods, which are simple but at the expense of losing robustness, missing fuzzy characteristics, and having inconsistent inference. The concept of optimal fuzzy reasoning is introduced in this paper to overcome these shortcomings. The main advantage is that an integration of the optimal fuzzy reasoning with a PID control structure will generate a new type of fuzzy-PID control schemes with inherent optimal-tuning features for both local optimal performance and global tracking robustness. This new fuzzy-PID controller is then analyzed quantitatively and compared with other existing fuzzy-PID control methods. Both analytical and numerical studies clearly show the improved robustness of the new fuzzy-PID controller.

  14. Robust Sliding Mode Control for Tokamaks

    Directory of Open Access Journals (Sweden)

    I. Garrido

    2012-01-01

    Full Text Available Nuclear fusion has arisen as an alternative energy to avoid carbon dioxide emissions, being the tokamak a promising nuclear fusion reactor that uses a magnetic field to confine plasma in the shape of a torus. However, different kinds of magnetohydrodynamic instabilities may affect tokamak plasma equilibrium, causing severe reduction of particle confinement and leading to plasma disruptions. In this sense, numerous efforts and resources have been devoted to seeking solutions for the different plasma control problems so as to avoid energy confinement time decrements in these devices. In particular, since the growth rate of the vertical instability increases with the internal inductance, lowering the internal inductance is a fundamental issue to address for the elongated plasmas employed within the advanced tokamaks currently under development. In this sense, this paper introduces a lumped parameter numerical model of the tokamak in order to design a novel robust sliding mode controller for the internal inductance using the transformer primary coil as actuator.

  15. Robust Force Control of Series Elastic Actuators

    Directory of Open Access Journals (Sweden)

    Andrea Calanca

    2014-07-01

    Full Text Available Force-controlled series elastic actuators (SEA are widely used in novel human-robot interaction (HRI applications, such as assistive and rehabilitation robotics. These systems are characterized by the presence of the “human in the loop”, so that control response and stability depend on uncertain human dynamics, including reflexes and voluntary forces. This paper proposes a force control approach that guarantees the stability and robustness of the coupled human-robot system, based on sliding-mode control (SMC, considering the human dynamics as a disturbance to reject. We propose a chattering free solution that employs simple task models to obtain high performance, comparable with second order solutions. Theoretical stability is proven within the sliding mode framework, and predictability is reached by avoiding the reaching phase by design. Furthermore, safety is introduced by a proper design of the sliding surface. The practical feasibility of the approach is shown using an SEA prototype coupled with a human impedance in severe stress tests. To show the quality of the approach, we report a comparison with state-of-the-art second order SMC, passivity-based control and adaptive control solutions.

  16. A hybrid robust fault tolerant control based on adaptive joint unscented Kalman filter.

    Science.gov (United States)

    Shabbouei Hagh, Yashar; Mohammadi Asl, Reza; Cocquempot, Vincent

    2017-01-01

    In this paper, a new hybrid robust fault tolerant control scheme is proposed. A robust H∞ control law is used in non-faulty situation, while a Non-Singular Terminal Sliding Mode (NTSM) controller is activated as soon as an actuator fault is detected. Since a linear robust controller is designed, the system is first linearized through the feedback linearization method. To switch from one controller to the other, a fuzzy based switching system is used. An Adaptive Joint Unscented Kalman Filter (AJUKF) is used for fault detection and diagnosis. The proposed method is based on the simultaneous estimation of the system states and parameters. In order to show the efficiency of the proposed scheme, a simulated 3-DOF robotic manipulator is used. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  17. Robust control of UAVs using the parameter space approach

    NARCIS (Netherlands)

    Abdelmoeti, Samer; Carloni, Raffaella

    2016-01-01

    In this paper a robust PID controller for quadrotor unmanned aerial vehicles is proposed that uses the pa- rameter space approach. Stability and robustness analyses are carried out in the controller parameter space to determine a set of stable controller gains that guarantee also robustness against

  18. Observer-Based Robust Control for Spacecraft Rendezvous with Thrust Saturation

    Directory of Open Access Journals (Sweden)

    Neng Wan

    2014-01-01

    Full Text Available This paper proposes an observer-based robust guaranteed cost control method for thrust-limited rendezvous in near-circular orbits. Treating the noncircularity of the target orbit as a parametric uncertainty, a linearized motion model derived from the two-body problem is adopted as the controlled plant. Based on this model, a robust guaranteed cost observer-controller is synthesized with a less conservative saturation control law, and sufficient condition for the existence of this observer-based rendezvous controller is derived. Finally, an illustrative example with immeasurable velocity states is presented to demonstrate the advantages and effectiveness of the control scheme.

  19. A MODEL AND CONTROLLER REDUCTION METHOD FOR ROBUST CONTROL DESIGN.

    Energy Technology Data Exchange (ETDEWEB)

    YUE,M.; SCHLUETER,R.

    2003-10-20

    A bifurcation subsystem based model and controller reduction approach is presented. Using this approach a robust {micro}-synthesis SVC control is designed for interarea oscillation and voltage control based on a small reduced order bifurcation subsystem model of the full system. The control synthesis problem is posed by structured uncertainty modeling and control configuration formulation using the bifurcation subsystem knowledge of the nature of the interarea oscillation caused by a specific uncertainty parameter. Bifurcation subsystem method plays a key role in this paper because it provides (1) a bifurcation parameter for uncertainty modeling; (2) a criterion to reduce the order of the resulting MSVC control; and (3) a low order model for a bifurcation subsystem based SVC (BMSVC) design. The use of the model of the bifurcation subsystem to produce a low order controller simplifies the control design and reduces the computation efforts so significantly that the robust {micro}-synthesis control can be applied to large system where the computation makes robust control design impractical. The RGA analysis and time simulation show that the reduced BMSVC control design captures the center manifold dynamics and uncertainty structure of the full system model and is capable of stabilizing the full system and achieving satisfactory control performance.

  20. Robust gene selection methods using weighting schemes for microarray data analysis.

    Science.gov (United States)

    Kang, Suyeon; Song, Jongwoo

    2017-09-02

    A common task in microarray data analysis is to identify informative genes that are differentially expressed between two different states. Owing to the high-dimensional nature of microarray data, identification of significant genes has been essential in analyzing the data. However, the performances of many gene selection techniques are highly dependent on the experimental conditions, such as the presence of measurement error or a limited number of sample replicates. We have proposed new filter-based gene selection techniques, by applying a simple modification to significance analysis of microarrays (SAM). To prove the effectiveness of the proposed method, we considered a series of synthetic datasets with different noise levels and sample sizes along with two real datasets. The following findings were made. First, our proposed methods outperform conventional methods for all simulation set-ups. In particular, our methods are much better when the given data are noisy and sample size is small. They showed relatively robust performance regardless of noise level and sample size, whereas the performance of SAM became significantly worse as the noise level became high or sample size decreased. When sufficient sample replicates were available, SAM and our methods showed similar performance. Finally, our proposed methods are competitive with traditional methods in classification tasks for microarrays. The results of simulation study and real data analysis have demonstrated that our proposed methods are effective for detecting significant genes and classification tasks, especially when the given data are noisy or have few sample replicates. By employing weighting schemes, we can obtain robust and reliable results for microarray data analysis.

  1. Robust Motion Control for Mobile Manipulator Using Resolved Acceleration and Proportional-Integral Active Force Control

    Directory of Open Access Journals (Sweden)

    Musa Mailah

    2005-06-01

    Full Text Available A resolved acceleration control (RAC and proportional-integral active force control (PIAFC is proposed as an approach for the robust motion control of a mobile manipulator (MM comprising a differentially driven wheeled mobile platform with a two-link planar arm mounted on top of the platform. The study emphasizes on the integrated kinematic and dynamic control strategy in which the RAC is used to manipulate the kinematic component while the PIAFC is implemented to compensate the dynamic effects including the bounded known/unknown disturbances and uncertainties. The effectivenss and robustness of the proposed scheme are investigated through a rigorous simulation study and later complemented with experimental results obtained through a number of experiments performed on a fully developed working prototype in a laboratory environment. A number of disturbances in the form of vibratory and impact forces are deliberately introduced into the system to evaluate the system performances. The investigation clearly demonstrates the extreme robustness feature of the proposed control scheme compared to other systems considered in the study.

  2. Robust control for snake maneuver design of missile

    Science.gov (United States)

    Kun, Ya; Chen, Xin; Li, Chuntao

    2017-01-01

    For the performance of missile with high Mach number and strongly nonlinear dynamics, this paper uses robust control to design maneuver controller. Robust servomechanism linear quadratic regulator (RSLQR) control is used to form the inner loop and proportional-plus-integral (PI) control is used to provide yawing tracking with no error. Contrast simulations under three types of deviation have been done to confirm robustness of the RSLQR-plus-PI control. Simulation results shows that RSLQR-plus-PI control would resist the disturbance and maintain the properties of the controller, guarantee the robustness and stability of missile more effectively than pure PI control.

  3. PI controller scheme for charge balance in implantable electrical ...

    Indian Academy of Sciences (India)

    Electrical stimulation has been used in a wide variety of medical implant applications. In all of these applications, due to safety concerns, maintaining charge balance becomes a critically important issue that needs to be addressed at the design stage. It is important that charge balancing schemes be robust to circuit ...

  4. Nonlinear H∞ Optimal Control Scheme for an Underwater Vehicle with Regional Function Formulation

    Directory of Open Access Journals (Sweden)

    Zool H. Ismail

    2013-01-01

    Full Text Available A conventional region control technique cannot meet the demands for an accurate tracking performance in view of its inability to accommodate highly nonlinear system dynamics, imprecise hydrodynamic coefficients, and external disturbances. In this paper, a robust technique is presented for an Autonomous Underwater Vehicle (AUV with region tracking function. Within this control scheme, nonlinear H∞ and region based control schemes are used. A Lyapunov-like function is presented for stability analysis of the proposed control law. Numerical simulations are presented to demonstrate the performance of the proposed tracking control of the AUV. It is shown that the proposed control law is robust against parameter uncertainties, external disturbances, and nonlinearities and it leads to uniform ultimate boundedness of the region tracking error.

  5. UAV Robust Strategy Control Based on MAS

    Directory of Open Access Journals (Sweden)

    Jian Han

    2014-01-01

    Full Text Available A novel multiagent system (MAS has been proposed to integrate individual UAV (unmanned aerial vehicle to form a UAV team which can accomplish complex missions with better efficiency and effect. The MAS based UAV team control is more able to conquer dynamic situations and enhance the performance of any single UAV. In this paper, the MAS proposed and established combines the reacting and thinking abilities to be an initiative and autonomous hybrid system which can solve missions involving coordinated flight and cooperative operation. The MAS uses BDI model to support its logical perception and to classify the different missions; then the missions will be allocated by utilizing auction mechanism after analyzing dynamic parameters. Prim potential algorithm, particle swarm algorithm, and reallocation mechanism are proposed to realize the rational decomposing and optimal allocation in order to reach the maximum profit. After simulation, the MAS has been proved to be able to promote the success ratio and raise the robustness, while realizing feasibility of coordinated flight and optimality of cooperative mission.

  6. Robust Control for the Segway with Unknown Control Coefficient and Model Uncertainties.

    Science.gov (United States)

    Kim, Byung Woo; Park, Bong Seok

    2016-06-29

    The Segway, which is a popular vehicle nowadays, is an uncertain nonlinear system and has an unknown time-varying control coefficient. Thus, we should consider the unknown time-varying control coefficient and model uncertainties to design the controller. Motivated by this observation, we propose a robust control for the Segway with unknown control coefficient and model uncertainties. To deal with the time-varying unknown control coefficient, we employ the Nussbaum gain technique. We introduce an auxiliary variable to solve the underactuated problem. Due to the prescribed performance control technique, the proposed controller does not require the adaptive technique, neural network, and fuzzy logic to compensate the uncertainties. Therefore, it can be simple. From the Lyapunov stability theory, we prove that all signals in the closed-loop system are bounded. Finally, we provide the simulation results to demonstrate the effectiveness of the proposed control scheme.

  7. Robust Control for the Segway with Unknown Control Coefficient and Model Uncertainties

    Directory of Open Access Journals (Sweden)

    Byung Woo Kim

    2016-06-01

    Full Text Available The Segway, which is a popular vehicle nowadays, is an uncertain nonlinear system and has an unknown time-varying control coefficient. Thus, we should consider the unknown time-varying control coefficient and model uncertainties to design the controller. Motivated by this observation, we propose a robust control for the Segway with unknown control coefficient and model uncertainties. To deal with the time-varying unknown control coefficient, we employ the Nussbaum gain technique. We introduce an auxiliary variable to solve the underactuated problem. Due to the prescribed performance control technique, the proposed controller does not require the adaptive technique, neural network, and fuzzy logic to compensate the uncertainties. Therefore, it can be simple. From the Lyapunov stability theory, we prove that all signals in the closed-loop system are bounded. Finally, we provide the simulation results to demonstrate the effectiveness of the proposed control scheme.

  8. Biologically inspired control of humanoid robot arms robust and adaptive approaches

    CERN Document Server

    Spiers, Adam; Herrmann, Guido

    2016-01-01

    This book investigates a biologically inspired method of robot arm control, developed with the objective of synthesising human-like motion dynamically, using nonlinear, robust and adaptive control techniques in practical robot systems. The control method caters to a rising interest in humanoid robots and the need for appropriate control schemes to match these systems. Unlike the classic kinematic schemes used in industrial manipulators, the dynamic approaches proposed here promote human-like motion with better exploitation of the robot’s physical structure. This also benefits human-robot interaction. The control schemes proposed in this book are inspired by a wealth of human-motion literature that indicates the drivers of motion to be dynamic, model-based and optimal. Such considerations lend themselves nicely to achievement via nonlinear control techniques without the necessity for extensive and complex biological models. The operational-space method of robot control forms the basis of many of the techniqu...

  9. MEMS gyroscope control using a novel compound robust control.

    Science.gov (United States)

    Rahmani, Mehran

    2018-01-01

    This paper proposes a new compound fractional order integral terminal sliding mode control (FOITSMC) and proportional-derivative control (PD-FOITSMC) for the control of a MEMS gyroscope. In order to improve the robustness of the conventional integral terminal sliding mode control (ITSMC), a fractional integral terminal sliding mode surface is applied. The chattering problem in FOITSMC, which is usually generated by the excitation of fast un-modelled dynamic is the main drawback. A PD controller is employed in order to eliminate chattering phenomenon. The stability of the PD-FOITSMC is proved by Lyapunov theory. The performance of the proposed control method is compared with two other controllers such as ITSMC and FOITSMC. Numerical simulations clearly verified the effectiveness of the proposed control approach. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Nonlinear robust hierarchical control for nonlinear uncertain systems

    Directory of Open Access Journals (Sweden)

    Leonessa Alexander

    1999-01-01

    Full Text Available A nonlinear robust control-system design framework predicated on a hierarchical switching controller architecture parameterized over a set of moving nominal system equilibria is developed. Specifically, using equilibria-dependent Lyapunov functions, a hierarchical nonlinear robust control strategy is developed that robustly stabilizes a given nonlinear system over a prescribed range of system uncertainty by robustly stabilizing a collection of nonlinear controlled uncertain subsystems. The robust switching nonlinear controller architecture is designed based on a generalized (lower semicontinuous Lyapunov function obtained by minimizing a potential function over a given switching set induced by the parameterized nominal system equilibria. The proposed framework robustly stabilizes a compact positively invariant set of a given nonlinear uncertain dynamical system with structured parametric uncertainty. Finally, the efficacy of the proposed approach is demonstrated on a jet engine propulsion control problem with uncertain pressure-flow map data.

  11. Knowledge-Based Trajectory Error Pattern Method Applied to an Active Force Control Scheme

    Directory of Open Access Journals (Sweden)

    Endra Pitowarno, Musa Mailah, Hishamuddin Jamaluddin

    2012-08-01

    Full Text Available The active force control (AFC method is known as a robust control scheme that dramatically enhances the performance of a robot arm particularly in compensating the disturbance effects. The main task of the AFC method is to estimate the inertia matrix in the feedback loop to provide the correct (motor torque required to cancel out these disturbances. Several intelligent control schemes have already been introduced to enhance the estimation methods of acquiring the inertia matrix such as those using neural network, iterative learning and fuzzy logic. In this paper, we propose an alternative scheme called Knowledge-Based Trajectory Error Pattern Method (KBTEPM to suppress the trajectory track error of the AFC scheme. The knowledge is developed from the trajectory track error characteristic based on the previous experimental results of the crude approximation method. It produces a unique, new and desirable error pattern when a trajectory command is forced. An experimental study was performed using simulation work on the AFC scheme with KBTEPM applied to a two-planar manipulator in which a set of rule-based algorithm is derived. A number of previous AFC schemes are also reviewed as benchmark. The simulation results show that the AFC-KBTEPM scheme successfully reduces the trajectory track error significantly even in the presence of the introduced disturbances.Key Words:  Active force control, estimated inertia matrix, robot arm, trajectory error pattern, knowledge-based.

  12. A Robust Controller Structure for Pico-Satellite Applications

    DEFF Research Database (Denmark)

    Kragelund, Martin Nygaard; Green, Martin; Kristensen, Mads

    This paper describes the development of a robust controller structure for use in pico-satellite missions. The structure relies on unknown disturbance estimation and use of robust control theory to implement a system that is robust to both unmodeled disturbances and parameter uncertainties. As one...... possible application, a satellite mission with the purpose of monitoring shipping routes for oil spills has been considered. However, it is the aim of the control structure to be widely applicable and adaptable for a vide variety of pico-satellite missions. The robust control structure has been evaluated...

  13. Ambiguity attacks on robust blind image watermarking scheme based on redundant discrete wavelet transform and singular value decomposition

    Directory of Open Access Journals (Sweden)

    Khaled Loukhaoukha

    2017-12-01

    Full Text Available Among emergent applications of digital watermarking are copyright protection and proof of ownership. Recently, Makbol and Khoo (2013 have proposed for these applications a new robust blind image watermarking scheme based on the redundant discrete wavelet transform (RDWT and the singular value decomposition (SVD. In this paper, we present two ambiguity attacks on this algorithm that have shown that this algorithm fails when used to provide robustness applications like owner identification, proof of ownership, and transaction tracking. Keywords: Ambiguity attack, Image watermarking, Singular value decomposition, Redundant discrete wavelet transform

  14. A Secure and Robust User Authenticated Key Agreement Scheme for Hierarchical Multi-medical Server Environment in TMIS.

    Science.gov (United States)

    Das, Ashok Kumar; Odelu, Vanga; Goswami, Adrijit

    2015-09-01

    The telecare medicine information system (TMIS) helps the patients to gain the health monitoring facility at home and access medical services over the Internet of mobile networks. Recently, Amin and Biswas presented a smart card based user authentication and key agreement security protocol usable for TMIS system using the cryptographic one-way hash function and biohashing function, and claimed that their scheme is secure against all possible attacks. Though their scheme is efficient due to usage of one-way hash function, we show that their scheme has several security pitfalls and design flaws, such as (1) it fails to protect privileged-insider attack, (2) it fails to protect strong replay attack, (3) it fails to protect strong man-in-the-middle attack, (4) it has design flaw in user registration phase, (5) it has design flaw in login phase, (6) it has design flaw in password change phase, (7) it lacks of supporting biometric update phase, and (8) it has flaws in formal security analysis. In order to withstand these security pitfalls and design flaws, we aim to propose a secure and robust user authenticated key agreement scheme for the hierarchical multi-server environment suitable in TMIS using the cryptographic one-way hash function and fuzzy extractor. Through the rigorous security analysis including the formal security analysis using the widely-accepted Burrows-Abadi-Needham (BAN) logic, the formal security analysis under the random oracle model and the informal security analysis, we show that our scheme is secure against possible known attacks. Furthermore, we simulate our scheme using the most-widely accepted and used Automated Validation of Internet Security Protocols and Applications (AVISPA) tool. The simulation results show that our scheme is also secure. Our scheme is more efficient in computation and communication as compared to Amin-Biswas's scheme and other related schemes. In addition, our scheme supports extra functionality features as compared to

  15. Robust Tracking Control of Mobile Robot Formation with Obstacle Avoidance

    Directory of Open Access Journals (Sweden)

    Tiantian Yang

    2007-01-01

    scheme is formulated as online solving each optimal control problem at each sampling time. Moreover, closed-loop properties inclusive of stability and H∞ performance are discussed. Finally, simulation is performed to highlight the effectiveness of the proposed control law.

  16. Implementation of a Cross-Layer Sensing Medium-Access Control Scheme.

    Science.gov (United States)

    Su, Yishan; Fu, Xiaomei; Han, Guangyao; Xu, Naishen; Jin, Zhigang

    2017-04-10

    In this paper, compressed sensing (CS) theory is utilized in a medium-access control (MAC) scheme for wireless sensor networks (WSNs). We propose a new, cross-layer compressed sensing medium-access control (CL CS-MAC) scheme, combining the physical layer and data link layer, where the wireless transmission in physical layer is considered as a compress process of requested packets in a data link layer according to compressed sensing (CS) theory. We first introduced using compressive complex requests to identify the exact active sensor nodes, which makes the scheme more efficient. Moreover, because the reconstruction process is executed in a complex field of a physical layer, where no bit and frame synchronizations are needed, the asynchronous and random requests scheme can be implemented without synchronization payload. We set up a testbed based on software-defined radio (SDR) to implement the proposed CL CS-MAC scheme practically and to demonstrate the validation. For large-scale WSNs, the simulation results show that the proposed CL CS-MAC scheme provides higher throughput and robustness than the carrier sense multiple access (CSMA) and compressed sensing medium-access control (CS-MAC) schemes.

  17. Simulation and stability analysis of neural network based control scheme for switched linear systems.

    Science.gov (United States)

    Singh, H P; Sukavanam, N

    2012-01-01

    This paper proposes a new adaptive neural network based control scheme for switched linear systems with parametric uncertainty and external disturbance. A key feature of this scheme is that the prior information of the possible upper bound of the uncertainty is not required. A feedforward neural network is employed to learn this upper bound. The adaptive learning algorithm is derived from Lyapunov stability analysis so that the system response under arbitrary switching laws is guaranteed uniformly ultimately bounded. A comparative simulation study with robust controller given in [Zhang L, Lu Y, Chen Y, Mastorakis NE. Robust uniformly ultimate boundedness control for uncertain switched linear systems. Computers and Mathematics with Applications 2008; 56: 1709-14] is presented. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Intelligent control schemes applied to Automatic Generation Control

    Directory of Open Access Journals (Sweden)

    Dingguo Chen

    2016-04-01

    Full Text Available Integrating ever increasing amount of renewable generating resources to interconnected power systems has created new challenges to the safety and reliability of today‟s power grids and posed new questions to be answered in the power system modeling, analysis and control. Automatic Generation Control (AGC must be extended to be able to accommodate the control of renewable generating assets. In addition, AGC is mandated to operate in accordance with the NERC‟s Control Performance Standard (CPS criteria, which represent a greater flexibility in relaxing the control of generating resources and yet assuring the stability and reliability of interconnected power systems when each balancing authority operates in full compliance. Enhancements in several aspects to the traditional AGC must be made in order to meet the aforementioned challenges. It is the intention of this paper to provide a systematic, mathematical formulation for AGC as a first attempt in the context of meeting the NERC CPS requirements and integrating renewable generating assets, which has not been seen reported in the literature to the best knowledge of the authors. Furthermore, this paper proposes neural network based predictive control schemes for AGC. The proposed controller is capable of handling complicated nonlinear dynamics in comparison with the conventional Proportional Integral (PI controller which is typically most effective to handle linear dynamics. The neural controller is designed in such a way that it has the capability of controlling the system generation in the relaxed manner so the ACE is controlled to a desired range instead of driving it to zero which would otherwise increase the control effort and cost; and most importantly the resulting system control performance meets the NERC CPS requirements and/or the NERC Balancing Authority’s ACE Limit (BAAL compliance requirements whichever are applicable.

  19. Multivariable Super Twisting Based Robust Trajectory Tracking Control for Small Unmanned Helicopter

    Directory of Open Access Journals (Sweden)

    Xing Fang

    2015-01-01

    Full Text Available This paper presents a highly robust trajectory tracking controller for small unmanned helicopter with model uncertainties and external disturbances. First, a simplified dynamic model is developed, where the model uncertainties and external disturbances are treated as compounded disturbances. Then the system is divided into three interconnected subsystems: altitude subsystem, yaw subsystem, and horizontal subsystem. Second, a disturbance observer based controller (DOBC is designed based upon backstepping and multivariable super twisting control algorithm to obtain robust trajectory tracking property. A sliding mode observer works as an estimator of the compounded disturbances. In order to lessen calculative burden, a first-order exact differentiator is employed to estimate the time derivative of the virtual control. Moreover, proof of the stability of the closed-loop system based on Lyapunov method is given. Finally, simulation results are presented to illustrate the effectiveness and robustness of the proposed flight control scheme.

  20. Application of a robust and efficient Lagrangian particle scheme to soot transport in turbulent flames

    KAUST Repository

    Attili, Antonio

    2013-09-01

    A Lagrangian particle scheme is applied to the solution of soot dynamics in turbulent nonpremixed flames. Soot particulate is described using a method of moments and the resulting set of continuum advection-reaction equations is solved using the Lagrangian particle scheme. The key property of the approach is the independence between advection, described by the movement of Lagrangian notional particles along pathlines, and internal aerosol processes, evolving on each notional particle via source terms. Consequently, the method overcomes the issues in Eulerian grid-based schemes for the advection of moments: errors in the advective fluxes pollute the moments compromising their realizability and the stiffness of source terms weakens the stability of the method. The proposed scheme exhibits superior properties with respect to conventional Eulerian schemes in terms of stability, accuracy, and grid convergence. Taking into account the quality of the solution, the Lagrangian approach can be computationally more economical than commonly used Eulerian schemes as it allows the resolution requirements dictated by the different physical phenomena to be independently optimized. Finally, the scheme posseses excellent scalability on massively parallel computers. © 2013 Elsevier Ltd.

  1. An ellipsoid algorithm for probabilistic robust controller design

    NARCIS (Netherlands)

    Kanev, S.K.; de Schutter, B.; Verhaegen, M.H.G.

    2003-01-01

    In this paper, a new iterative approach to probabilistic robust controller design is presented, which is applicable to any robust controller/filter design problem that can be represented as an LMI feasibility problem. Recently, a probabilistic Subgradient Iteration algorithm was proposed for solving

  2. Robust Control of an Ill-Conditioned Aircraft

    DEFF Research Database (Denmark)

    Breslin, S.G.; Tøffner-Clausen, S.; Grimble, M.J.

    1996-01-01

    A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point.......A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point....

  3. Variable-Structure Direct Torque Control – A Class of Fast and Robust Controllers for Induction Machine Drives

    DEFF Research Database (Denmark)

    Lascu, Christian; Boldea, Ion; Blaabjerg, Frede

    2004-01-01

    A family of variable-structure controllers for induction machine drives is presented, in which the principles of direct torque control (DTC), variable-structure control (VSC) and space-vector pulsewidth modulation are combined to ensure high-performance operation, both in the steady state and under...... transient conditions. Three new VSC schemes are designed following the DTC voltage-control-based philosophy. These provide robust, fast and accurate torque and flux control, without the penalty of high chattering. Comparative results demonstrate that proposed techniques preserve the DTC transient merits......, while the steady-state behaviour is significantly improved. Experimental results prove the strong robustness, accuracy, quickness and low-ripple sensorless operation of the drive that uses the new schemes....

  4. Robust Control Allocation for Spacecraft Attitude Stabilization under Actuator Faults and Uncertainty

    Directory of Open Access Journals (Sweden)

    Aihua Zhang

    2014-01-01

    Full Text Available A robust control allocation scheme is developed for rigid spacecraft attitude stabilization in the presence of actuator partial loss fault, actuator failure, and actuator misalignment. First, a neural network fault detection scheme is proposed, Second, an adaptive attitude tracking strategy is employed which can realize fault tolerance control under the actuator partial loss and actuator failure within λmin⁡=0.5. The attitude tracking and faults detection are always here during the procedure. Once the fault occurred which could not guaranteed the attitude stable for 30 s, the robust control allocation strategy is generated automatically. The robust control allocation compensates the control effectiveness uncertainty which caused the actuator misalignment. The unknown disturbances, uncertain inertia matrix, and even actuator error with limited actuators are all considered in the controller design process. All are achieved with inexpensive online computations. Numerical results are also presented that not only highlight the closed-loop performance benefits of the control law derived here but also illustrate its great robustness.

  5. Robust Propulsion Control for Improved Aircraft Safety Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Scientific Monitoring, Inc. proposes to develop a robust propulsion control approach to facilitate control law design and simulation-based validation. The proposed...

  6. Computation of robustly stabilizing PID controllers for interval systems

    National Research Council Canada - National Science Library

    Matušů, Radek; Prokop, Roman

    2016-01-01

    ....) technique for calculation of (nominally) stabilizing PI and PID controllers or robustly stabilizing PI controllers by means of plotting the stability boundary locus in either P-I plane or P-I-D space...

  7. A Microprocessor Control Scheme For Switched Reluctance Motor Drives

    Science.gov (United States)

    Oza, A. R.; Krishnan, R.; Adkar, S.

    1987-10-01

    A microprocessor control scheme for a switched reluctance motor(SRM) drive is discussed. A SRM is inherently a variable speed machine since it requires a converter even for constant speed running. Starting with a conceptual development, a particular hardware scheme is discussed for controller implementation. Hardware-software tradeoffs incorporated in the design are discussed. Some results of an actual system are evaluated. It is shown that a microprocessor controller has many advantages over conventional controllers. The controller design uses rotor position and speed feedbacks. Self-starting is incorporated into the design. Use of off-the-shelf components makes the controller simple, reliable, and economical.

  8. Time-division-multiplex control scheme for voltage multiplier rectifiers

    Directory of Open Access Journals (Sweden)

    Bin-Han Liu

    2017-03-01

    Full Text Available A voltage multiplier rectifier with a novel time-division-multiplexing (TDM control scheme for high step-up converters is proposed in this study. In the proposed TDM control scheme, two full-wave voltage doubler rectifiers can be combined to realise a voltage quadrupler rectifier. The proposed voltage quadrupler rectifier can reduce transformer turn ratio and transformer size for high step-up converters and also reduce voltage stress for the output capacitors and rectifier diodes. An N-times voltage rectifier can be straightforwardly produced by extending the concepts from the proposed TDM control scheme. A phase-shift full-bridge (PSFB converter is adopted in the primary side of the proposed voltage quadrupler rectifier to construct a PSFB quadrupler converter. Experimental results for the PSFB quadrupler converter demonstrate the performance of the proposed TDM control scheme for voltage quadrupler rectifiers. An 8-times voltage rectifier is simulated to determine the validity of extending the proposed TDM control scheme to realise an N-times voltage rectifier. Experimental and simulation results show that the proposed TDM control scheme has great potential to be used in high step-up converters.

  9. Efficient robust control of first order scalar conservation laws using semi-analytical solutions

    KAUST Repository

    Li, Yanning

    2014-01-01

    This article presents a new robust control framework for transportation problems in which the state is modeled by a first order scalar conservation law. Using an equivalent formulation based on a Hamilton-Jacobi equation, we pose the problem of controlling the state of the system on a network link, using initial density control and boundary flow control, as a Linear Program. We then show that this framework can be extended to arbitrary control problems involving the control of subsets of the initial and boundary conditions. Unlike many previously investigated transportation control schemes, this method yields a globally optimal solution and is capable of handling shocks (i.e. discontinuities in the state of the system). We also demonstrate that the same framework can handle robust control problems, in which the uncontrollable components of the initial and boundary conditions are encoded in intervals on the right hand side of inequalities in the linear program. The lower bound of the interval which defines the smallest feasible solution set is used to solve the robust LP/MILP. Since this framework leverages the intrinsic properties of the Hamilton-Jacobi equation used to model the state of the system, it is extremely fast. Several examples are given to demonstrate the performance of the robust control solution and the trade-off between the robustness and the optimality.

  10. Hybrid Robust Control Law with Disturbance Observer for High-Frequency Response Electro-Hydraulic Servo Loading System

    Directory of Open Access Journals (Sweden)

    Zhiqing Sheng

    2016-04-01

    Full Text Available Addressing the simulating issue of the helicopter-manipulating booster aerodynamic load with high-frequency dynamic load superimposed on a large static load, this paper studies the design of the robust controller for the electro-hydraulic loading system to realize the simulation of this kind of load. Firstly, the equivalent linear model of the electro-hydraulic loading system under assumed parameter uncertainty is established. Then, a hybrid control scheme is proposed for the loading system. This control scheme consists of a constant velocity feed-forward compensator, a robust inner loop compensator based on disturbance observer and a robust outer loop feedback controller. The constant velocity compensator eliminates most of the extraneous force at first, and then the double-loop cascade composition control strategy is employed to design the compensated system. The disturbance observer–based inner loop compensator further restrains the disturbances including the remaining extraneous force, and makes the actual plant tracking a nominal model approximately in a certain frequency range. The robust outer loop controller achieves the desired force-tracking performance, and guarantees system robustness in the high frequency region. The optimized low-pass filter Q(s is designed by using the H∞ mixed sensitivity optimization method. The simulation results show that the proposed hybrid control scheme and controller can effectively suppress the extraneous force and improve the robustness of the electro-hydraulic loading system.

  11. Robustness aspects of Model Predictive Control

    OpenAIRE

    Megías Jiménez, David

    2011-01-01

    Model, Model-based or Receding-horizon Predictive Control (MPC or RHPC) is a successful and mature control strategy which has gained the widespread acceptance of both academia and industry. The basis of these control laws, which have been reported to handle quite complex dynamics, is to perform predictions of the system to be controlled by means of a model. A control profile is then computed to minimise some cost function defined in terms of the predictions and the hypothesised controls. It w...

  12. Panaceas, uncertainty, and the robust control framework in sustainability science.

    Science.gov (United States)

    Anderies, John M; Rodriguez, Armando A; Janssen, Marco A; Cifdaloz, Oguzhan

    2007-09-25

    A critical challenge faced by sustainability science is to develop strategies to cope with highly uncertain social and ecological dynamics. This article explores the use of the robust control framework toward this end. After briefly outlining the robust control framework, we apply it to the traditional Gordon-Schaefer fishery model to explore fundamental performance-robustness and robustness-vulnerability trade-offs in natural resource management. We find that the classic optimal control policy can be very sensitive to parametric uncertainty. By exploring a large class of alternative strategies, we show that there are no panaceas: even mild robustness properties are difficult to achieve, and increasing robustness to some parameters (e.g., biological parameters) results in decreased robustness with respect to others (e.g., economic parameters). On the basis of this example, we extract some broader themes for better management of resources under uncertainty and for sustainability science in general. Specifically, we focus attention on the importance of a continual learning process and the use of robust control to inform this process.

  13. Robust CUSUM control charting for process dispersion

    NARCIS (Netherlands)

    Nazir, H.Z.; Riaz, M.; Does, R.J.M.M.

    2015-01-01

    Process monitoring through control charts is a quite popular practice in statistical process control. From a statistical point of view, a superior control chart is one that has an efficient design structure, but having resistance against unusual situations is of more practical importance. To have a

  14. A Robustness Study of Fuzzy Control Rules

    DEFF Research Database (Denmark)

    Jantzen, Jan

    1997-01-01

    This simulation study investigates how different types of rule bases affect the control of different types of plant. In Simulink three nonlinear control surfaces have been tested and compared to a linear surface. It is recommended to be aware of the shape of the control surface, and carefully...

  15. Robust two-level system control by a detuned and chirped laser pulse

    Science.gov (United States)

    Jo, Hanlae; Lee, Han-gyeol; Guérin, Stéphane; Ahn, Jaewook

    2017-09-01

    We propose and demonstrate a robust control scheme by an ultrafast nonadiabatic chirped laser pulse, designed for targeting coherent superpositions of two-level systems. Robustness against power fluctuation is proved by our numerical study and a proof-of-principle experiment performed with femtosecond laser interaction on cold atoms. They exhibit for the final driven dynamics a cusp on the Bloch sphere, corresponding to a zero curvature of fidelity. This solution is particularly simple and thus applicable to a wide range of potential applications.

  16. Robust tracking and distributed synchronization control of a multi-motor servomechanism with H-infinity performance.

    Science.gov (United States)

    Wang, Minlin; Ren, Xuemei; Chen, Qiang

    2017-10-21

    The multi-motor servomechanism (MMS) is a multi-variable, high coupling and nonlinear system, which makes the controller design challenging. In this paper, an adaptive robust H-infinity control scheme is proposed to achieve both the load tracking and multi-motor synchronization of MMS. This control scheme consists of two parts: a robust tracking controller and a distributed synchronization controller. The robust tracking controller is constructed by incorporating a neural network (NN) K-filter observer into the dynamic surface control, while the distributed synchronization controller is designed by combining the mean deviation coupling control strategy with the distributed technique. The proposed control scheme has several merits: 1) by using the mean deviation coupling synchronization control strategy, the tracking controller and the synchronization controller can be designed individually without any coupling problem; 2) the immeasurable states and unknown nonlinearities are handled by a NN K-filter observer, where the number of NN weights is largely reduced by using the minimal learning parameter technique; 3) the H-infinity performances of tracking error and synchronization error are guaranteed by introducing a robust term into the tracking controller and the synchronization controller, respectively. The stabilities of the tracking and synchronization control systems are analyzed by the Lyapunov theory. Simulation and experimental results based on a four-motor servomechanism are conducted to demonstrate the effectiveness of the proposed method. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  17. Decentralized Feedback Controllers for Robust Stabilization of Periodic Orbits of Hybrid Systems: Application to Bipedal Walking.

    Science.gov (United States)

    Hamed, Kaveh Akbari; Gregg, Robert D

    2017-07-01

    This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially and robustly stabilize periodic orbits for hybrid dynamical systems against possible uncertainties in discrete-time phases. The algorithm assumes a family of parameterized and decentralized nonlinear controllers to coordinate interconnected hybrid subsystems based on a common phasing variable. The exponential and [Formula: see text] robust stabilization problems of periodic orbits are translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities. By investigating the properties of the Poincaré map, some sufficient conditions for the convergence of the iterative algorithm are presented. The power of the algorithm is finally demonstrated through designing a set of robust stabilizing local nonlinear controllers for walking of an underactuated 3D autonomous bipedal robot with 9 degrees of freedom, impact model uncertainties, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg.

  18. Robust control of linear descriptor systems

    CERN Document Server

    Feng, Yu

    2017-01-01

    This book develops original results regarding singular dynamic systems following two different paths. The first consists of generalizing results from classical state-space cases to linear descriptor systems, such as dilated linear matrix inequality (LMI) characterizations for descriptor systems and performance control under regulation constraints. The second is a new path, which considers descriptor systems as a powerful tool for conceiving new control laws, understanding and deciphering some controller’s architecture and even homogenizing different—existing—ways of obtaining some new and/or known results for state-space systems. The book also highlights the comprehensive control problem for descriptor systems as an example of using the descriptor framework in order to transform a non-standard control problem into a classic stabilization control problem. In another section, an accurate solution is derived for the sensitivity constrained linear optimal control also using the descriptor framework. The boo...

  19. Closed-Loop and Robust Control of Quantum Systems

    Directory of Open Access Journals (Sweden)

    Chunlin Chen

    2013-01-01

    Full Text Available For most practical quantum control systems, it is important and difficult to attain robustness and reliability due to unavoidable uncertainties in the system dynamics or models. Three kinds of typical approaches (e.g., closed-loop learning control, feedback control, and robust control have been proved to be effective to solve these problems. This work presents a self-contained survey on the closed-loop and robust control of quantum systems, as well as a brief introduction to a selection of basic theories and methods in this research area, to provide interested readers with a general idea for further studies. In the area of closed-loop learning control of quantum systems, we survey and introduce such learning control methods as gradient-based methods, genetic algorithms (GA, and reinforcement learning (RL methods from a unified point of view of exploring the quantum control landscapes. For the feedback control approach, the paper surveys three control strategies including Lyapunov control, measurement-based control, and coherent-feedback control. Then such topics in the field of quantum robust control as H∞ control, sliding mode control, quantum risk-sensitive control, and quantum ensemble control are reviewed. The paper concludes with a perspective of future research directions that are likely to attract more attention.

  20. A robust haze-removal scheme in polarimetric dehazing imaging based on automatic identification of sky region

    Science.gov (United States)

    Zhang, Wenfei; Liang, Jian; Ju, Haijuan; Ren, Liyong; Qu, Enshi; Wu, Zhaoxin

    2016-12-01

    Quality enhancement of images acquired in hazy conditions is a significant research area in civil and military applications. The polarimetric dehazing methods have been exploited to dehaze hazy images and have proven to be effective in enhancing their quality. In this paper, by combining the polarimetric imaging technique and the dark channel prior technique, a robust haze-removal scheme is presented for the first time. On the one hand, the polarimetric imaging technique has advantages in recovering detailed information well, especially in dense hazy conditions; on the other hand, the dark channel prior technique provides a much more precise and convenient way to estimate the airlight radiance through extracting the sky region automatically. The experiments verify the practicability and effectiveness of the proposed dehazing scheme in quality enhancement of hazy images. Furthermore, comparison study demonstrates that the proposed scheme is superior to some sophisticated methods in terms of the visibility and contrast. We believe this scheme is beneficial in the image dehazing applications, especially for real-time applications.

  1. A robust cooperative spectrum sensing scheme based on Dempster-Shafer theory and trustworthiness degree calculation in cognitive radio networks

    Science.gov (United States)

    Wang, Jinlong; Feng, Shuo; Wu, Qihui; Zheng, Xueqiang; Xu, Yuhua; Ding, Guoru

    2014-12-01

    Cognitive radio (CR) is a promising technology that brings about remarkable improvement in spectrum utilization. To tackle the hidden terminal problem, cooperative spectrum sensing (CSS) which benefits from the spatial diversity has been studied extensively. Since CSS is vulnerable to the attacks initiated by malicious secondary users (SUs), several secure CSS schemes based on Dempster-Shafer theory have been proposed. However, the existing works only utilize the current difference of SUs, such as the difference in SNR or similarity degree, to evaluate the trustworthiness of each SU. As the current difference is only one-sided and sometimes inaccurate, the statistical information contained in each SU's historical behavior should not be overlooked. In this article, we propose a robust CSS scheme based on Dempster-Shafer theory and trustworthiness degree calculation. It is carried out in four successive steps, which are basic probability assignment (BPA), trustworthiness degree calculation, selection and adjustment of BPA, and combination by Dempster-Shafer rule, respectively. Our proposed scheme evaluates the trustworthiness degree of SUs from both current difference aspect and historical behavior aspect and exploits Dempster-Shafer theory's potential to establish a `soft update' approach for the reputation value maintenance. It can not only differentiate malicious SUs from honest ones based on their historical behaviors but also reserve the current difference for each SU to achieve a better real-time performance. Abundant simulation results have validated that the proposed scheme outperforms the existing ones under the impact of different attack patterns and different number of malicious SUs.

  2. Robust Adaptive Control Using a Filtering Action

    Science.gov (United States)

    2009-09-01

    Control and Signal Processing (ALCOSP 2007). Saint Petersburg, RUSSIA August 2007. [65] R. K. Miller and G. R. Sell, Volterra Integral Equations and...Experimental Results with Modified L1 Adaptive Controller and FSS. .........82 Figure C.1. Region of Integration for Equation (C.2...is that 1 1 ( ) ( ) D p E p is a PID controller, with the integral action to satisfy Equation (4.3), and the derivative action to make its inverse

  3. ROBUST CONTROL OF OSCILLATIONS IN AGRICULTURAL TRACTORS

    DEFF Research Database (Denmark)

    Andersen, T. O.; Hansen, M. R.; Conrad, Finn

    2003-01-01

    for agricultural tractors equiped with hicth and implements. A control strategy is developed to make the implement counteract the movement of the tractor and thereby reducing the pitching oscillation. The control strategy is based on a linear plant model with constant or slowly varying parameters. Using...

  4. Robust Control of Laddermill Wind Energy System

    NARCIS (Netherlands)

    Podgaets, A.R.; Ockels, W.J.

    2007-01-01

    Laddermill flight control problem with closed loop is considered in this paper. Laddermill is an alternative concept for energy production using high altitude kites. The kites have been simulated as rigid bodies and the cable as a thin elastic line. Euler angles and cable speed are controls. Flight

  5. Linear systems optimal and robust control

    CERN Document Server

    Sinha, Alok

    2007-01-01

    Introduction Overview Contents of the Book State Space Description of a Linear System Transfer Function of a Single Input/Single Output (SISO) System State Space Realizations of a SISO System SISO Transfer Function from a State Space Realization Solution of State Space Equations Observability and Controllability of a SISO System Some Important Similarity Transformations Simultaneous Controllability and Observability Multiinput/Multioutput (MIMO) Systems State Space Realizations of a Transfer Function Matrix Controllability and Observability of a MIMO System Matrix-Fraction Description (MFD) MFD of a Transfer Function Matrix for the Minimal Order of a State Space Realization Controller Form Realization from a Right MFD Poles and Zeros of a MIMO Transfer Function Matrix Stability Analysis State Feedback Control and Optimization State Variable Feedback for a Single Input System Computation of State Feedback Gain Matrix for a Multiinput System State Feedback Gain Matrix for a Multi...

  6. An Industrial Model Based Disturbance Feedback Control Scheme

    DEFF Research Database (Denmark)

    Kawai, Fukiko; Nakazawa, Chikashi; Vinther, Kasper

    2014-01-01

    This paper presents a model based disturbance feedback control scheme. Industrial process systems have been traditionally controlled by using relay and PID controller. However these controllers are affected by disturbances and model errors and these effects degrade control performance. The authors...... propose a new control method that can decrease the negative impact of disturbance and model errors. The control method is motivated by industrial practice by Fuji Electric. Simulation tests are examined with a conventional PID controller and the disturbance feedback control. The simulation results...... demonstrate the effectiveness of the proposed method comparing with the conventional PID controller...

  7. Computation of robustly stabilizing PID controllers for interval systems.

    Science.gov (United States)

    Matušů, Radek; Prokop, Roman

    2016-01-01

    The paper is focused on the computation of all possible robustly stabilizing Proportional-Integral-Derivative (PID) controllers for plants with interval uncertainty. The main idea of the proposed method is based on Tan's (et al.) technique for calculation of (nominally) stabilizing PI and PID controllers or robustly stabilizing PI controllers by means of plotting the stability boundary locus in either P-I plane or P-I-D space. Refinement of the existing method by consideration of 16 segment plants instead of 16 Kharitonov plants provides an elegant and efficient tool for finding all robustly stabilizing PID controllers for an interval system. The validity and relatively effortless application of presented theoretical concepts are demonstrated through a computation and simulation example in which the uncertain mathematical model of an experimental oblique wing aircraft is robustly stabilized.

  8. Incremental Sampling Algorithms for Robust Propulsion Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aurora Flight Sciences proposes to develop a system for robust engine control based on incremental sampling, specifically Rapidly-Expanding Random Tree (RRT)...

  9. Quantitative Robust Control Engineering: Theory and Applications

    Science.gov (United States)

    2006-09-01

    to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data...the D tank as a dashed line [mg/l] and the control input IR(t) is shown as a solid line [ per unit of the influent flow rate] with the G22(z...1992). Discrete quantitative feedback technique, Capítulo 16 en el libro : Digital Control Systems: theory, hardware, software, 2ª edicion. McGraw

  10. Exact solutions to robust control problems involving scalar hyperbolic conservation laws using Mixed Integer Linear Programming

    KAUST Repository

    Li, Yanning

    2013-10-01

    This article presents a new robust control framework for transportation problems in which the state is modeled by a first order scalar conservation law. Using an equivalent formulation based on a Hamilton-Jacobi equation, we pose the problem of controlling the state of the system on a network link, using boundary flow control, as a Linear Program. Unlike many previously investigated transportation control schemes, this method yields a globally optimal solution and is capable of handling shocks (i.e. discontinuities in the state of the system). We also demonstrate that the same framework can handle robust control problems, in which the uncontrollable components of the initial and boundary conditions are encoded in intervals on the right hand side of inequalities in the linear program. The lower bound of the interval which defines the smallest feasible solution set is used to solve the robust LP (or MILP if the objective function depends on boolean variables). Since this framework leverages the intrinsic properties of the Hamilton-Jacobi equation used to model the state of the system, it is extremely fast. Several examples are given to demonstrate the performance of the robust control solution and the trade-off between the robustness and the optimality. © 2013 IEEE.

  11. The EWMA control chart based on robust scale estimators

    OpenAIRE

    Nadia Saeed; Shahid Kamal

    2016-01-01

    The exponentially weighted moving average (EWMA) chart is very popular in statistical process control for detecting the small shifts in process mean and variance. This chart performs well under the assumption of normality but when data violate the assumption of normality, the robust approaches needed. We have developed the EWMA charts under different robust scale estimators available in literature and also compared the performance of these charts by calculating expected out-of-control points ...

  12. Robust control applied induction machine employed of Matlab/ Simulink

    Directory of Open Access Journals (Sweden)

    José Paulo Fernandes Garcia

    2003-01-01

    Full Text Available This work refers the approach of a control strategy/metodology for control of the induction machine in high performace. The classic method presented in the literature [1], they are composed of controllers PID’s acting in the strategy of control of the speed of the machine. The mathematical model of the induction machine after an appropriate treatment, equaly leads to the mathematical model of the machine of continuous current, which the control strategy is much simpler. The proposal of this work was to use of a new control methodology that is more reliable and mainly robust and that assists the performance requirements and stability. It is be described that the method of Robust Control showed the robustness conditions, stability and performance.

  13. Robustness

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Rizzuto, Enrico; Narasimhan, Harikrishna

    2012-01-01

    More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of structures...

  14. Tracking error constrained robust adaptive neural prescribed performance control for flexible hypersonic flight vehicle

    Directory of Open Access Journals (Sweden)

    Zhonghua Wu

    2017-02-01

    Full Text Available A robust adaptive neural control scheme based on a back-stepping technique is developed for the longitudinal dynamics of a flexible hypersonic flight vehicle, which is able to ensure the state tracking error being confined in the prescribed bounds, in spite of the existing model uncertainties and actuator constraints. Minimal learning parameter technique–based neural networks are used to estimate the model uncertainties; thus, the amount of online updated parameters is largely lessened, and the prior information of the aerodynamic parameters is dispensable. With the utilization of an assistant compensation system, the problem of actuator constraint is overcome. By combining the prescribed performance function and sliding mode differentiator into the neural back-stepping control design procedure, a composite state tracking error constrained adaptive neural control approach is presented, and a new type of adaptive law is constructed. As compared with other adaptive neural control designs for hypersonic flight vehicle, the proposed composite control scheme exhibits not only low-computation property but also strong robustness. Finally, two comparative simulations are performed to demonstrate the robustness of this neural prescribed performance controller.

  15. Robust disturbance rejection control of a biped robotic system using high-order extended state observer.

    Science.gov (United States)

    Martínez-Fonseca, Nadhynee; Castañeda, Luis Ángel; Uranga, Agustín; Luviano-Juárez, Alberto; Chairez, Isaac

    2016-05-01

    This study addressed the problem of robust control of a biped robot based on disturbance estimation. Active disturbance rejection control was the paradigm used for controlling the biped robot by direct active estimation. A robust controller was developed to implement disturbance cancelation based on a linear extended state observer of high gain class. A robust high-gain scheme was proposed for developing a state estimator of the biped robot despite poor knowledge of the plant and the presence of uncertainties. The estimated states provided by the state estimator were used to implement a feedback controller that was effective in actively rejecting the perturbations as well as forcing the trajectory tracking error to within a small vicinity of the origin. The theoretical convergence of the tracking error was proven using the Lyapunov theory. The controller was implemented by numerical simulations that showed the convergence of the tracking error. A comparison with a high-order sliding-mode-observer-based controller confirmed the superior performance of the controller using the robust observer introduced in this study. Finally, the proposed controller was implemented on an actual biped robot using an embedded hardware-in-the-loop strategy. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  16. Audio Watermarking Scheme Robust against Desynchronization Based on the Dyadic Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Jiwu Huang

    2010-01-01

    Full Text Available Digital watermarking is a technique used to embed an extra piece of information into multimedia signals without degrading the signal quality. For robust audio watermarking, geometrical modifications are common operations and present many challenges because they severely alter the tempo or spectral structures of the audio and thus cause watermark desynchronization. However, most of the existing audio watermarking algorithms lack resynchronization ability due to the nongeometrically-invariant nature of the watermarking domain. In this paper, we consider the dyadic wavelet transform (DYWT for its geometrical invariants which can help resynchronize the watermark. We then design a novel embedding method based on shape modulation which is demonstrated to be robust against many kinds of attack. Based on the knowledge of the insertion, deletion, and substitution (IDS channel, we carefully design a novel error correction coding (ECC with the ability of bit-resynchronization to correct the IDS errors in the watermark. Compared with existing algorithms, our algorithm achieves greater robustness to geometrical modifications and other common operations.

  17. UAV Robust Strategy Control Based on MAS

    OpenAIRE

    Jian Han; Changhong Wang; Guoxing Yi

    2014-01-01

    A novel multiagent system (MAS) has been proposed to integrate individual UAV (unmanned aerial vehicle) to form a UAV team which can accomplish complex missions with better efficiency and effect. The MAS based UAV team control is more able to conquer dynamic situations and enhance the performance of any single UAV. In this paper, the MAS proposed and established combines the reacting and thinking abilities to be an initiative and autonomous hybrid system which can solve missions involving coo...

  18. Robust fast controller design via nonlinear fractional differential equations.

    Science.gov (United States)

    Zhou, Xi; Wei, Yiheng; Liang, Shu; Wang, Yong

    2017-07-01

    A new method for linear system controller design is proposed whereby the closed-loop system achieves both robustness and fast response. The robustness performance considered here means the damping ratio of closed-loop system can keep its desired value under system parameter perturbation, while the fast response, represented by rise time of system output, can be improved by tuning the controller parameter. We exploit techniques from both the nonlinear systems control and the fractional order systems control to derive a novel nonlinear fractional order controller. For theoretical analysis of the closed-loop system performance, two comparison theorems are developed for a class of fractional differential equations. Moreover, the rise time of the closed-loop system can be estimated, which facilitates our controller design to satisfy the fast response performance and maintain the robustness. Finally, numerical examples are given to illustrate the effectiveness of our methods. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Robust PID control design for permanent magnet synchronous motor: A genetic approach

    Energy Technology Data Exchange (ETDEWEB)

    Jan, Rong-Maw; Tseng, Chung-Shi; Liu, Ren-Jun [Department of Electrical Engineering, Ming Hsin University of Science and Technology, Hsin-Feng 30401 (China)

    2008-07-15

    In this paper, a robust PID control scheme is proposed for the permanent magnet synchronous motor (PMSM) using a genetic searching approach. Genetic algorithms (GAs) are powerful searching algorithms based on the mechanics of natural selection and natural genetics. Based on a simple genetic algorithm, a set of PID parameters can be obtained such that the robust stability for the closed-loop system is guaranteed, the tracking performance is minimized subject to certain related cost function, and the disturbance rejection ability (H{sub {infinity}} performance) subject to a prescribed attenuation level can also be achieved. Numerical solutions of the PID parameters constrained by three different objectives and simulation results are provided to illustrate the design procedure and the expected performances. Finally, the proposed PID control scheme for the PMSM is implemented by a DSP-based fully digital controller. From the experimental results, the performances can be achieved using the proposed PID control scheme. In opposition to trial and error, the PID parameters can be obtained systematically in this study. The proposed method is simple and is suitable for practical control design in the motor drive. (author)

  20. Novel coupling scheme to control dynamics of coupled discrete systems

    Science.gov (United States)

    Shekatkar, Snehal M.; Ambika, G.

    2015-08-01

    We present a new coupling scheme to control spatio-temporal patterns and chimeras on 1-d and 2-d lattices and random networks of discrete dynamical systems. The scheme involves coupling with an external lattice or network of damped systems. When the system network and external network are set in a feedback loop, the system network can be controlled to a homogeneous steady state or synchronized periodic state with suppression of the chaotic dynamics of the individual units. The control scheme has the advantage that its design does not require any prior information about the system dynamics or its parameters and works effectively for a range of parameters of the control network. We analyze the stability of the controlled steady state or amplitude death state of lattices using the theory of circulant matrices and Routh-Hurwitz criterion for discrete systems and this helps to isolate regions of effective control in the relevant parameter planes. The conditions thus obtained are found to agree well with those obtained from direct numerical simulations in the specific context of lattices with logistic map and Henon map as on-site system dynamics. We show how chimera states developed in an experimentally realizable 2-d lattice can be controlled using this scheme. We propose this mechanism can provide a phenomenological model for the control of spatio-temporal patterns in coupled neurons due to non-synaptic coupling with the extra cellular medium. We extend the control scheme to regulate dynamics on random networks and adapt the master stability function method to analyze the stability of the controlled state for various topologies and coupling strengths.

  1. Optimal and robust feedback controller estimation for a vibrating plate

    NARCIS (Netherlands)

    Fraanje, P.R.; Verhaegen, M.; Doelman, N.J.; Berkhoff, A.

    2004-01-01

    This paper presents a method to estimate the H2 optimal and a robust feedback controller by means of Subspace Model Identification using the internal model control (IMC) approach. Using IMC an equivalent feed forward control problem is obtained, which is solved by the Causal Wiener filter for the H2

  2. Robust control of post-stall pitching maneuver based on finite-time observer.

    Science.gov (United States)

    Wu, Dawei; Chen, Mou; Gong, Huajun

    2017-09-01

    This article presents a robust finite-time maneuver control scheme for the longitudinal attitude dynamic of the aircraft with unsteady aerodynamic disturbances and input saturation. To efficiently eliminate the influence of unsteady aerodynamic disturbances, nonlinear finite-time observers are developed. Despite the existence of the nonlinearity and the coupling between aircraft states and unsteady aerodynamic disturbances, the proposed observers can still precisely estimate the unmeasurable unsteady aerodynamic disturbances in finite time. To attenuate the effect caused by input saturation, a finite-time auxiliary system is constructed. With the error between the desired control input and saturation input as the input of the auxiliary system, the additional signals are generated to compensate for the effect of input saturation. Combined with the finite-time observers and the finite-time auxiliary system, a robust finite-time backstepping attitude control design is developed. The finite-time convergence of all closed-loop system signals is rigorously proved via Lyapunov analysis method under the developed robust attitude control schemes. Finally, simulation results are presented to illustrate the effectiveness of the proposed attitude control approaches. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  3. A Computational Framework to Control Verification and Robustness Analysis

    Science.gov (United States)

    Crespo, Luis G.; Kenny, Sean P.; Giesy, Daniel P.

    2010-01-01

    This paper presents a methodology for evaluating the robustness of a controller based on its ability to satisfy the design requirements. The framework proposed is generic since it allows for high-fidelity models, arbitrary control structures and arbitrary functional dependencies between the requirements and the uncertain parameters. The cornerstone of this contribution is the ability to bound the region of the uncertain parameter space where the degradation in closed-loop performance remains acceptable. The size of this bounding set, whose geometry can be prescribed according to deterministic or probabilistic uncertainty models, is a measure of robustness. The robustness metrics proposed herein are the parametric safety margin, the reliability index, the failure probability and upper bounds to this probability. The performance observed at the control verification setting, where the assumptions and approximations used for control design may no longer hold, will fully determine the proposed control assessment.

  4. Hierarchical Control Scheme for Voltage Unbalance Compensation in Islanded Microgrids

    DEFF Research Database (Denmark)

    Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza

    2011-01-01

    The concept of microgrid hierarchical control is presented, recently. In this paper, a hierarchical scheme which includes primary and secondary control levels is proposed for islanded microgrids. The primary control level consists of DG local controllers. Local controller of each DG comprises...... active and reactive power controllers, virtual impedance loop and voltage and current controllers. The secondary level is designed to compensate the voltage unbalance at the load bus (LB) of the islanded microgrid. Also, restoration of LB voltage amplitude and microgrid frequency to the rated values...

  5. Fault tolerant control schemes using integral sliding modes

    CERN Document Server

    Hamayun, Mirza Tariq; Alwi, Halim

    2016-01-01

    The key attribute of a Fault Tolerant Control (FTC) system is its ability to maintain overall system stability and acceptable performance in the face of faults and failures within the feedback system. In this book Integral Sliding Mode (ISM) Control Allocation (CA) schemes for FTC are described, which have the potential to maintain close to nominal fault-free performance (for the entire system response), in the face of actuator faults and even complete failures of certain actuators. Broadly an ISM controller based around a model of the plant with the aim of creating a nonlinear fault tolerant feedback controller whose closed-loop performance is established during the design process. The second approach involves retro-fitting an ISM scheme to an existing feedback controller to introduce fault tolerance. This may be advantageous from an industrial perspective, because fault tolerance can be introduced without changing the existing control loops. A high fidelity benchmark model of a large transport aircraft is u...

  6. The effect of the signalling scheme on the robustness of pattern formation in development

    KAUST Repository

    Kang, H.-W.

    2012-03-21

    Pattern formation in development is a complex process which involves spatially distributed signals called morphogens that influence gene expression and thus the phenotypic identity of cells. Usually different cell types are spatially segregated, and the boundary between them may be determined by a threshold value of some state variable. The question arises as to how sensitive the location of such a boundary is to variations in properties, such as parameter values, that characterize the system. Here, we analyse both deterministic and stochastic reaction-diffusion models of pattern formation with a view towards understanding how the signalling scheme used for patterning affects the variability of boundary determination between cell types in a developing tissue.

  7. The EWMA control chart based on robust scale estimators

    Directory of Open Access Journals (Sweden)

    Nadia Saeed

    2016-12-01

    Full Text Available The exponentially weighted moving average (EWMA chart is very popular in statistical process control for detecting the small shifts in process mean and variance. This chart performs well under the assumption of normality but when data violate the assumption of normality, the robust approaches needed. We have developed the EWMA charts under different robust scale estimators available in literature and also compared the performance of these charts by calculating expected out-of-control points and expected widths under non-symmetric distributions (i.e. gamma and exponential. The simulation studies are being carried out for the purpose and results showed that amongst six robust estimators, the chart based on estimator Q_n relatively performed well for non-normal processes in terms of its shorter expected width and more number of expected out-of-control points which shows its sensitivity to detect the out of control signal.

  8. Interpolation techniques in robust constrained model predictive control

    Science.gov (United States)

    Kheawhom, Soorathep; Bumroongsri, Pornchai

    2017-05-01

    This work investigates interpolation techniques that can be employed on off-line robust constrained model predictive control for a discrete time-varying system. A sequence of feedback gains is determined by solving off-line a series of optimal control optimization problems. A sequence of nested corresponding robustly positive invariant set, which is either ellipsoidal or polyhedral set, is then constructed. At each sampling time, the smallest invariant set containing the current state is determined. If the current invariant set is the innermost set, the pre-computed gain associated with the innermost set is applied. If otherwise, a feedback gain is variable and determined by a linear interpolation of the pre-computed gains. The proposed algorithms are illustrated with case studies of a two-tank system. The simulation results showed that the proposed interpolation techniques significantly improve control performance of off-line robust model predictive control without much sacrificing on-line computational performance.

  9. Robust Adaptive Speed Control of Induction Motor Drives

    DEFF Research Database (Denmark)

    Bidstrup, N.

    and measurement noise in general, were the major reasons for the drifting parameters. Two approaches was proposed to robustify MASTR2 against the output noise. The first approach consists of filtering the output. Output filtering had a significant effect in simulations, but the robustness against the output noise...... was little in practice. The seccond approach was only to update the controller parameters when excitation in load occurred. This was achieved by incorporating a dead zone in the estimator. This approach had significant effect on the robustness against output noise both in simulations and in practice......, (LS) identification and generalized predictive control (GPC) has been implemented and tested on the CVC drive. Allthough GPC is a robust control method, it was not possible to maintain specified controller performance in the entire operating range. This was the main reason for investigating truly...

  10. Robust decentralized power system controller design: Integrated approach

    Science.gov (United States)

    Veselý, Vojtech

    2017-09-01

    A unique approach to the design of gain scheduled controller (GSC) is presented. The proposed design procedure is based on the Bellman-Lyapunov equation, guaranteed cost and robust stability conditions using the parameter dependent quadratic stability approach. The obtained feasible design procedures for robust GSC design are in the form of BMI with guaranteed convex stability conditions. The obtained design results and their properties are illustrated in the simultaneously design of controllers for simple model (6-order) turbogenerator. The results of the obtained design procedure are a PI automatic voltage regulator (AVR) for synchronous generator, a PI governor controller and a power system stabilizer for excitation system.

  11. Computation of robustly stabilizing PID controllers for interval systems

    OpenAIRE

    Matušů, Radek; Prokop, Roman

    2016-01-01

    The paper is focused on the computation of all possible robustly stabilizing Proportional-Integral-Derivative (PID) controllers for plants with interval uncertainty. The main idea of the proposed method is based on Tan?s (et al.) technique for calculation of (nominally) stabilizing PI and PID controllers or robustly stabilizing PI controllers by means of plotting the stability boundary locus in either P-I plane or P-I-D space. Refinement of the existing method by consideration of 16 segment p...

  12. Robust Droop Control of Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Elkayam, Moria; Kuperman, Alon; Guerrero, Josep M.

    2016-01-01

    . Despite the benefits of distributed generation, the drawback is that large grid-side impedance steps can cause a system to become unstable. A robust control method based on disturbance observer is proposed in this paper. When the proposed robust controller is utilized, closed loop performance remains......The use of distributed generation in microgrid systems is becoming a popular way to provide a reliable source of electricity to critical loads. Droop control techniques are used in power systems for the synchronization of grid-connected inverters by local measurements of active and reactive powers...

  13. STRUCTURAL SYNTHESIS OF A STABILIZING ROBUST CONTROLLER OF THE ROTOR FLUX LINKAGE

    Directory of Open Access Journals (Sweden)

    N. J. Khlopenko

    2017-03-01

    Full Text Available Purpose. The aim is to structural synthesis of robust stabilizing control of the rotor flux vector control system of induction motor. Methodology. Synthesis controller structure was carried out in two stages. The first stage constructed a mathematical model of the channel of the rotor flux with parametric uncertainty and calculated transfer function of H∞-suboptimal controller by method of the mixed sensitivity. The second stage was carried out the expansion of the transfer function of the continued fraction for the Euclidean algorithm. This fraction was used to construct the controller structural scheme. Results. Computer modeling of the transfer function of H∞-suboptimal controller. Achieved decomposition found the transfer function of the continued fraction. The flow diagram of suboptimal H∞-controller with a proportional and integrating links and a few summers. The curves of transient rotor flux linkage in packages Robust Control Toolbox and Simulink. They coincide in the steady state, but differ among themselves in the transition. Originality. We developed the method of structural synthesis of robust stabilizing controller of the flux linkage rotor, H∞-suboptimal structural scheme of which is presented in the form of simple compounds integrating and proportional elements of the same order as the controller with the strictly correct transfer function, and takes into account the parametric uncertainty of control object. The results of the simulation of transient processes in a variety of packages MATLAB applications confirms the adequacy and small sensitivity of the system to parametric perturbation. Practical value. The resulting structure of the controller makes it possible to carry out the modernization of electric control systems, in use, with minimal financial costs.

  14. A hybrid iterative scheme for optimal control problems governed by ...

    African Journals Online (AJOL)

    This paper presents an iterative approach based on hybrid of perturbation and parametrization methods for obtaining approximate solutions of optimal control problems governed by some Fredholm integral equations. By some numerical examples, it is emphasized that this scheme is very effective and it produces ...

  15. Robust passivity-based control of switched-reluctance motors

    OpenAIRE

    Loria, Antonio; Espinosa-Pérez, G.; Chumacero, Erik

    2015-01-01

    International audience; We propose a state-feedback controller for switched-reluctance motors as a preliminary step towards the solution of the sensorless control problem (without measurement of rotor variables). We establish global exponential stability. Furthermore, our controller renders the closed-loop system robust to external disturbances that is, input-to-state stable. Although there exist some works on sensorless control of switched-reluctance motors, these consist mainly on ad hoc so...

  16. Smooth and robust solutions for Dirichlet boundary control of fluid-solid conjugate heat transfer problems

    KAUST Repository

    Yan, Yan

    2015-01-01

    We study a new optimization scheme that generates smooth and robust solutions for Dirichlet velocity boundary control (DVBC) of conjugate heat transfer (CHT) processes. The solutions to the DVBC of the incompressible Navier-Stokes equations are typically nonsmooth, due to the regularity degradation of the boundary stress in the adjoint Navier-Stokes equations. This nonsmoothness is inherited by the solutions to the DVBC of CHT processes, since the CHT process couples the Navier-Stokes equations of fluid motion with the convection-diffusion equations of fluid-solid thermal interaction. Our objective in the CHT boundary control problem is to select optimally the fluid inflow profile that minimizes an objective function that involves the sum of the mismatch between the temperature distribution in the fluid system and a prescribed temperature profile and the cost of the control.Our strategy to resolve the nonsmoothness of the boundary control solution is based on two features, namely, the objective function with a regularization term on the gradient of the control profile on both the continuous and the discrete levels, and the optimization scheme with either explicit or implicit smoothing effects, such as the smoothed Steepest Descent and the Limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) methods. Our strategy to achieve the robustness of the solution process is based on combining the smoothed optimization scheme with the numerical continuation technique on the regularization parameters in the objective function. In the section of numerical studies, we present two suites of experiments. In the first one, we demonstrate the feasibility and effectiveness of our numerical schemes in recovering the boundary control profile of the standard case of a Poiseuille flow. In the second one, we illustrate the robustness of our optimization schemes via solving more challenging DVBC problems for both the channel flow and the flow past a square cylinder, which use initial

  17. Robust linear parameter varying induction motor control with polytopic models

    Directory of Open Access Journals (Sweden)

    Dalila Khamari

    2013-01-01

    Full Text Available This paper deals with a robust controller for an induction motor which is represented as a linear parameter varying systems. To do so linear matrix inequality (LMI based approach and robust Lyapunov feedback controller are associated. This new approach is related to the fact that the synthesis of a linear parameter varying (LPV feedback controller for the inner loop take into account rotor resistance and mechanical speed as varying parameter. An LPV flux observer is also synthesized to estimate rotor flux providing reference to cited above regulator. The induction motor is described as a polytopic model because of speed and rotor resistance affine dependence their values can be estimated on line during systems operations. The simulation results are presented to confirm the effectiveness of the proposed approach where robustness stability and high performances have been achieved over the entire operating range of the induction motor.

  18. Optimal Robust Motion Controller Design Using Multiobjective Genetic Algorithm

    Science.gov (United States)

    Svečko, Rajko

    2014-01-01

    This paper describes the use of a multiobjective genetic algorithm for robust motion controller design. Motion controller structure is based on a disturbance observer in an RIC framework. The RIC approach is presented in the form with internal and external feedback loops, in which an internal disturbance rejection controller and an external performance controller must be synthesised. This paper involves novel objectives for robustness and performance assessments for such an approach. Objective functions for the robustness property of RIC are based on simple even polynomials with nonnegativity conditions. Regional pole placement method is presented with the aims of controllers' structures simplification and their additional arbitrary selection. Regional pole placement involves arbitrary selection of central polynomials for both loops, with additional admissible region of the optimized pole location. Polynomial deviation between selected and optimized polynomials is measured with derived performance objective functions. A multiobjective function is composed of different unrelated criteria such as robust stability, controllers' stability, and time-performance indexes of closed loops. The design of controllers and multiobjective optimization procedure involve a set of the objectives, which are optimized simultaneously with a genetic algorithm—differential evolution. PMID:24987749

  19. Synchronization and Desynchronizing Control Schemes for Supermarket Refrigeration Systems

    DEFF Research Database (Denmark)

    Larsen, Lars Finn Sloth; Thybo, Claus Thybo; Izadi-Zamanabadi, Roozbeh

    2007-01-01

    A supermarket refrigeration system is a hybrid system with switched nonlinear dynamics and discrete-valued input variables such as opening/closing of valves and start/stop of compressors. Practical and simulation studies have shown that the use of distributed hysteresis controllers to operate...... the valves leads to synchronization, meaning that the opening and closing actions of the valves coincide. Consequently, the compressor periodically has to work hard resulting in low efficiency, inferior control performance and a high wear on the compressor. In this paper we propose two control schemes of low...... complexity for desynchronizing the valve operations while improving performance. Simulation results indicate the potential increase in efficiency and reduction in wear comparing with traditional control schemes....

  20. Adaptive Robust Actuator Fault Accommodation for a Class of Uncertain Nonlinear Systems with Unknown Control Gains

    Directory of Open Access Journals (Sweden)

    Yuefei Wu

    2014-01-01

    Full Text Available An adaptive robust fault tolerant control approach is proposed for a class of uncertain nonlinear systems with unknown signs of high-frequency gain and unmeasured states. In the recursive design, neural networks are employed to approximate the unknown nonlinear functions, K-filters are designed to estimate the unmeasured states, and a dynamical signal and Nussbaum gain functions are introduced to handle the unknown sign of the virtual control direction. By incorporating the switching function σ algorithm, the adaptive backstepping scheme developed in this paper does not require the real value of the actuator failure. It is mathematically proved that the proposed adaptive robust fault tolerant control approach can guarantee that all the signals of the closed-loop system are bounded, and the output converges to a small neighborhood of the origin. The effectiveness of the proposed approach is illustrated by the simulation examples.

  1. Context-dependent adaptation improves robustness of myoelectric control for upper-limb prostheses

    Science.gov (United States)

    Patel, Gauravkumar K.; Hahne, Janne M.; Castellini, Claudio; Farina, Dario; Dosen, Strahinja

    2017-10-01

    Objective. Dexterous upper-limb prostheses are available today to restore grasping, but an effective and reliable feed-forward control is still missing. The aim of this work was to improve the robustness and reliability of myoelectric control by using context information from sensors embedded within the prosthesis. Approach. We developed a context-driven myoelectric control scheme (cxMYO) that incorporates the inference of context information from proprioception (inertial measurement unit) and exteroception (force and grip aperture) sensors to modulate the outputs of myoelectric control. Further, a realistic evaluation of the cxMYO was performed online in able-bodied subjects using three functional tasks, during which the cxMYO was compared to a purely machine-learning-based myoelectric control (MYO). Main results. The results demonstrated that utilizing context information decreased the number of unwanted commands, improving the performance (success rate and dropped objects) in all three functional tasks. Specifically, the median number of objects dropped per round with cxMYO was zero in all three tasks and a significant increase in the number of successful transfers was seen in two out of three functional tasks. Additionally, the subjects reported better user experience. Significance. This is the first online evaluation of a method integrating information from multiple on-board prosthesis sensors to modulate the output of a machine-learning-based myoelectric controller. The proposed scheme is general and presents a simple, non-invasive and cost-effective approach for improving the robustness of myoelectric control.

  2. Robust self-triggered coordination with ternary controllers

    NARCIS (Netherlands)

    De Persis, Claudio; Frasca, Paolo

    2013-01-01

    This paper regards the coordination of networked systems, studied in the framework of hybrid dynamical systems. We design a coordination scheme which combines the use of ternary controllers with a self-triggered communication policy. The communication policy requires the agents to measure, at each

  3. Robust formation control of marine surface craft using Lagrange multipliers

    DEFF Research Database (Denmark)

    Ihle, Ivar-Andre F.; Jouffroy, Jerome; Fossen, Thor I.

    2006-01-01

    This paper presents a formation modelling scheme based on a set of inter-body constraint functions and Lagrangian multipliers. Formation control for a °eet of marine craft is achieved by stabilizing the auxiliary constraints such that the desired formation con¯guration appears. In the proposed...

  4. Robust Control for High-Speed Visual Servoing Applications

    DEFF Research Database (Denmark)

    Ellekilde, Lars-Peter; Favrholdt, Peter; Paulin, Mads

    2007-01-01

    This paper presents a new control scheme for visual servoing applications. The approach employs quadratic optimization, and explicitly handles both joint position, velocity and acceleration limits. Contrary to existing techniques, our method does not rely on large safety margins and slow task exe...

  5. Robust design of feedback feed-forward iterative learning control based on 2D system theory for linear uncertain systems

    Science.gov (United States)

    Li, Zhifu; Hu, Yueming; Li, Di

    2016-08-01

    For a class of linear discrete-time uncertain systems, a feedback feed-forward iterative learning control (ILC) scheme is proposed, which is comprised of an iterative learning controller and two current iteration feedback controllers. The iterative learning controller is used to improve the performance along the iteration direction and the feedback controllers are used to improve the performance along the time direction. First of all, the uncertain feedback feed-forward ILC system is presented by an uncertain two-dimensional Roesser model system. Then, two robust control schemes are proposed. One can ensure that the feedback feed-forward ILC system is bounded-input bounded-output stable along time direction, and the other can ensure that the feedback feed-forward ILC system is asymptotically stable along time direction. Both schemes can guarantee the system is robust monotonically convergent along the iteration direction. Third, the robust convergent sufficient conditions are given, which contains a linear matrix inequality (LMI). Moreover, the LMI can be used to determine the gain matrix of the feedback feed-forward iterative learning controller. Finally, the simulation results are presented to demonstrate the effectiveness of the proposed schemes.

  6. Region of interest based robust watermarking scheme for adaptation in small displays

    Science.gov (United States)

    Vivekanandhan, Sapthagirivasan; K. B., Kishore Mohan; Vemula, Krishna Manohar

    2010-02-01

    Now-a-days Multimedia data can be easily replicated and the copyright is not legally protected. Cryptography does not allow the use of digital data in its original form and once the data is decrypted, it is no longer protected. Here we have proposed a new double protected digital image watermarking algorithm, which can embed the watermark image blocks into the adjacent regions of the host image itself based on their blocks similarity coefficient which is robust to various noise effects like Poisson noise, Gaussian noise, Random noise and thereby provide double security from various noises and hackers. As instrumentation application requires a much accurate data, the watermark image which is to be extracted back from the watermarked image must be immune to various noise effects. Our results provide better extracted image compared to the present/existing techniques and in addition we have done resizing the same for various displays. Adaptive resizing for various size displays is being experimented wherein we crop the required information in a frame, zoom it for a large display or resize for a small display using a threshold value and in either cases background is not given much importance but it is only the fore-sight object which gains importance which will surely be helpful in performing surgeries.

  7. Robust hopping based on virtual pendulum posture control.

    Science.gov (United States)

    Sharbafi, Maziar A; Maufroy, Christophe; Ahmadabadi, Majid Nili; Yazdanpanah, Mohammad J; Seyfarth, Andre

    2013-09-01

    A new control approach to achieve robust hopping against perturbations in the sagittal plane is presented in this paper. In perturbed hopping, vertical body alignment has a significant role for stability. Our approach is based on the virtual pendulum concept, recently proposed, based on experimental findings in human and animal locomotion. In this concept, the ground reaction forces are pointed to a virtual support point, named virtual pivot point (VPP), during motion. This concept is employed in designing the controller to balance the trunk during the stance phase. New strategies for leg angle and length adjustment besides the virtual pendulum posture control are proposed as a unified controller. This method is investigated by applying it on an extension of the spring loaded inverted pendulum (SLIP) model. Trunk, leg mass and damping are added to the SLIP model in order to make the model more realistic. The stability is analyzed by Poincaré map analysis. With fixed VPP position, stability, disturbance rejection and moderate robustness are achieved, but with a low convergence speed. To improve the performance and attain higher robustness, an event-based control of the VPP position is introduced, using feedback of the system states at apexes. Discrete linear quartic regulator is used to design the feedback controller. Considerable enhancements with respect to stability, convergence speed and robustness against perturbations and parameter changes are achieved.

  8. Robust multiple frequency multiple power localization schemes in the presence of multiple jamming attacks.

    Directory of Open Access Journals (Sweden)

    Ahmed Abdulqader Hussein

    Full Text Available Localization of the wireless sensor network is a vital area acquiring an impressive research concern and called upon to expand more with the rising of its applications. As localization is gaining prominence in wireless sensor network, it is vulnerable to jamming attacks. Jamming attacks disrupt communication opportunity among the sender and receiver and deeply impact the localization process, leading to a huge error of the estimated sensor node position. Therefore, detection and elimination of jamming influence are absolutely indispensable. Range-based techniques especially Received Signal Strength (RSS is facing severe impact of these attacks. This paper proposes algorithms based on Combination Multiple Frequency Multiple Power Localization (C-MFMPL and Step Function Multiple Frequency Multiple Power Localization (SF-MFMPL. The algorithms have been tested in the presence of multiple types of jamming attacks including capture and replay, random and constant jammers over a log normal shadow fading propagation model. In order to overcome the impact of random and constant jammers, the proposed method uses two sets of frequencies shared by the implemented anchor nodes to obtain the averaged RSS readings all over the transmitted frequencies successfully. In addition, three stages of filters have been used to cope with the replayed beacons caused by the capture and replay jammers. In this paper the localization performance of the proposed algorithms for the ideal case which is defined by without the existence of the jamming attack are compared with the case of jamming attacks. The main contribution of this paper is to achieve robust localization performance in the presence of multiple jamming attacks under log normal shadow fading environment with a different simulation conditions and scenarios.

  9. ROBUST TEMPERATURE CONTROLLER DESIGN FOR A CHEMICAL PROCESS

    OpenAIRE

    G.Glan Devadhas; Dr.S.Pushpa Kumar

    2010-01-01

    This paper attempts to tuning out a new PID control strategy to provide Robust Control for a Chemical process. Chemical process control is a challenging problem due to the strong on-line non-linearity and extreme sensitivity to disturbances of the process. The proposed method has the advantage that it takes into account all the parameters variations associated with the process. The variations in the process parameters are modeled as a gaussian noise and an adaptive gaussian filter is placed i...

  10. Robust and optimal control a two-port framework approach

    CERN Document Server

    Tsai, Mi-Ching

    2014-01-01

    A Two-port Framework for Robust and Optimal Control introduces an alternative approach to robust and optimal controller synthesis procedures for linear, time-invariant systems, based on the two-port system widespread in electrical engineering. The novel use of the two-port system in this context allows straightforward engineering-oriented solution-finding procedures to be developed, requiring no mathematics beyond linear algebra. A chain-scattering description provides a unified framework for constructing the stabilizing controller set and for synthesizing H2 optimal and H∞ sub-optimal controllers. Simple yet illustrative examples explain each step. A Two-port Framework for Robust and Optimal Control  features: ·         a hands-on, tutorial-style presentation giving the reader the opportunity to repeat the designs presented and easily to modify them for their own programs; ·         an abundance of examples illustrating the most important steps in robust and optimal design; and ·   �...

  11. Robust Stabilization of Nonlinear Systems with Uncertain Varying Control Coefficient

    Directory of Open Access Journals (Sweden)

    Zaiyue Yang

    2014-01-01

    Full Text Available This paper investigates the stabilization problem for a class of nonlinear systems, whose control coefficient is uncertain and varies continuously in value and sign. The study emphasizes the development of a robust control that consists of a modified Nussbaum function to tackle the uncertain varying control coefficient. By such a method, the finite-time escape phenomenon has been prevented when the control coefficient is crossing zero and varying its sign. The proposed control guarantees the asymptotic stabilization of the system and boundedness of all closed-loop signals. The control performance is illustrated by a numerical simulation.

  12. Robust integration schemes for junction-based modulators in a 200mm CMOS compatible silicon photonic platform (Conference Presentation)

    Science.gov (United States)

    Szelag, Bertrand; Abraham, Alexis; Brision, Stéphane; Gindre, Paul; Blampey, Benjamin; Myko, André; Olivier, Segolene; Kopp, Christophe

    2017-05-01

    Silicon photonic is becoming a reality for next generation communication system addressing the increasing needs of HPC (High Performance Computing) systems and datacenters. CMOS compatible photonic platforms are developed in many foundries integrating passive and active devices. The use of existing and qualified microelectronics process guarantees cost efficient and mature photonic technologies. Meanwhile, photonic devices have their own fabrication constraints, not similar to those of cmos devices, which can affect their performances. In this paper, we are addressing the integration of PN junction Mach Zehnder modulator in a 200mm CMOS compatible photonic platform. Implantation based device characteristics are impacted by many process variations among which screening layer thickness, dopant diffusion, implantation mask overlay. CMOS devices are generally quite robust with respect to these processes thanks to dedicated design rules. For photonic devices, the situation is different since, most of the time, doped areas must be carefully located within waveguides and CMOS solutions like self-alignment to the gate cannot be applied. In this work, we present different robust integration solutions for junction-based modulators. A simulation setup has been built in order to optimize of the process conditions. It consist in a Mathlab interface coupling process and device electro-optic simulators in order to run many iterations. Illustrations of modulator characteristic variations with process parameters are done using this simulation setup. Parameters under study are, for instance, X and Y direction lithography shifts, screening oxide and slab thicknesses. A robust process and design approach leading to a pn junction Mach Zehnder modulator insensitive to lithography misalignment is then proposed. Simulation results are compared with experimental datas. Indeed, various modulators have been fabricated with different process conditions and integration schemes. Extensive

  13. Robust stabilization of nonlinear systems by quantized and ternary control

    NARCIS (Netherlands)

    Persis, Claudio De

    2009-01-01

    Results on the problem of stabilizing a nonlinear continuous-time minimum-phase system by a finite number of control or measurement values are presented. The basic tool is a discontinuous version of the so-called semi-global backstepping lemma. We derive robust practical stabilizability results by

  14. Robust time-optimal control of uncertain structural dynamic systems

    Science.gov (United States)

    Wie, Bong; Sinha, Ravi; Liu, Qiang

    1993-01-01

    A time-optimal open-loop control problem of flexible spacecraft in the presence of modeling uncertainty has been investigated. The results indicate that the proposed approach significantly reduces the residual structural vibrations caused by modeling uncertainty. The results also indicate the importance of proper jet placement for practical tradeoffs among the maneuvering time, fuel consumption, and performance robustness.

  15. Robust Adaptive Speed Control of Induction Motor Drives

    DEFF Research Database (Denmark)

    Bidstrup, N.

    was little in practice. The seccond approach was only to update the controller parameters when excitation in load occurred. This was achieved by incorporating a dead zone in the estimator. This approach had significant effect on the robustness against output noise both in simulations and in practice...

  16. Robust Control Algorithm for a Two Cart System and an Inverted Pendulum

    Science.gov (United States)

    Wilson, Chris L.; Capo-Lugo, Pedro

    2011-01-01

    The Rectilinear Control System can be used to simulate a launch vehicle during liftoff. Several control schemes have been developed that can control different dynamic models of the rectilinear plant. A robust control algorithm was developed that can control a pendulum to maintain an inverted position. A fluid slosh tank will be attached to the pendulum in order to test robustness in the presence of unknown slosh characteristics. The rectilinear plant consists of a DC motor and three carts mounted in series. Each cart s weight can be adjusted with brass masses and the carts can be coupled with springs. The pendulum is mounted on the first cart and an adjustable air damper can be attached to the third cart if desired. Each cart and the pendulum have a quadrature encoder to determine position. Full state feedback was implemented in order to develop the control algorithm along with a state estimator to determine the velocity states of the system. A MATLAB program was used to convert the state space matrices from continuous time to discrete time. This program also used a desired phase margin and damping ratio to determine the feedback gain matrix that would be used in the LabVIEW program. This experiment will allow engineers to gain a better understanding of liquid propellant slosh dynamics, therefore enabling them to develop more robust control algorithms for launch vehicle systems

  17. Robust Adaptive Speed Control of Induction Motor Drives

    DEFF Research Database (Denmark)

    Bidstrup, N.

    This thesis concerns speed control of current vector controlled induction motor drives (CVC drives). The CVC drive is an existing prototype drive developed by Danfoss A/S, Transmission Division. Practical tests have revealed that the open loop dynamical properties of the CVC drive are highly......, (LS) identification and generalized predictive control (GPC) has been implemented and tested on the CVC drive. Allthough GPC is a robust control method, it was not possible to maintain specified controller performance in the entire operating range. This was the main reason for investigating truly...

  18. Designing a robust PID congestion controller supporting TCP flows based on H∞ optimal control theory

    Science.gov (United States)

    Yu, Li; Shi, Zibo; Chen, Kun; Shu, Yantai

    2007-09-01

    A robust PID controller for active queue management (AQM) based on modern H∞ optimal control theory is presented in this paper. Taken both robustness and closed loop performance into consideration, most desirable parameters value can be gotten through some straightforward analytical formulas. Our robust PID controller is determined only by one parameter, other than traditional PID controller is by three or more. Additionally, this new parameters determining method can not only be extended to other AQM controller based on classical control theory or optimal control theory, but also be easily understood and implementation. We evaluate the performances of the controller extensively. The results show that the robust PID congestion controller outperform the existing controller, such as PI, RED, on keeping the router queue size at the target value. The most obvious property of the controller is that it takes on robustness such that it can adapt the network dynamic.

  19. Robust reactor power control system design by genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yoon Joon; Cho, Kyung Ho; Kim, Sin [Cheju National University, Cheju (Korea, Republic of)

    1997-12-31

    The H{sub {infinity}} robust controller for the reactor power control system is designed by use of the mixed weight sensitivity. The system is configured into the typical two-port model with which the weight functions are augmented. Since the solution depends on the weighting functions and the problem is of nonconvex, the genetic algorithm is used to determine the weighting functions. The cost function applied in the genetic algorithm permits the direct control of the power tracking performances. In addition, the actual operating constraints such as rod velocity and acceleration can be treated as design parameters. Compared with the conventional approach, the controller designed by the genetic algorithm results in the better performances with the realistic constraints. Also, it is found that the genetic algorithm could be used as an effective tool in the robust design. 4 refs., 6 figs. (Author)

  20. DK-iteration robust control design of a wind turbine

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2011-01-01

    The problem of robust control of a wind turbine is considered in this paper. A controller is designed based on a 2 degrees of freedom linearized model. An extended Kalman filter is used to estimate effective wind speed and the estimated wind speed is used to find the operating point of the wind...... turbine. Due to imprecise wind speed estimation, uncertainty in the obtained linear model is considered. Uncertainties in the drivetrain stiffness and damping parameters are also considered as these values are lumped parameters of a distributed system and therefore they include inherent uncertainties. We...... include these uncertainties as parametric uncertainties in the model and design a robust controller using DK-iteration method. The controller is applied on a full complexity simulation model and simulations are performed for wind speed step changes....

  1. Robust H2/H∞ Control for the Electrohydraulic Steering System of a Four-Wheel Vehicle

    Directory of Open Access Journals (Sweden)

    Min Ye

    2014-01-01

    Full Text Available To shorten the steer diameter and to improve the maneuverability flexibility of a construction vehicle, four wheels’ steering system is presented. This steering system consists of mechanical-electrical-hydraulic assemblies. Its diagram and principle are depicted in detail. Then the mathematical models are derived step by step, including the whole vehicle model and the hydraulic route model. Considering the nonlinear and time-varying uncertainty of the steering system, robust H2/H∞ controller is put forward to guarantee both the system performance and the robust stability. The H∞ norm of the sensitive function from the parameter perturbation of the hydraulic system to the yaw velocity of the vehicle is taken as the evaluating index of the robustness and the H2 norm of the transfer function from the external disturbance to the steering angle of the wheel as the index of linear quadratic Gaussian. The experimental results showed that the proposed scheme was superior to classical PID controller and can guarantee both the control performance and the robustness of the steering system.

  2. Impedance Control for Robotic Rehabilitation: A Robust Markovian Approach

    Directory of Open Access Journals (Sweden)

    Andres L. Jutinico

    2017-08-01

    Full Text Available The human-robot interaction has played an important role in rehabilitation robotics and impedance control has been used in the regulation of interaction forces between the robot actuator and human limbs. Series elastic actuators (SEAs have been an efficient solution in the design of this kind of robotic application. Standard implementations of impedance control with SEAs require an internal force control loop for guaranteeing the desired impedance output. However, nonlinearities and uncertainties hamper such a guarantee of an accurate force level in this human-robot interaction. This paper addresses the dependence of the impedance control performance on the force control and proposes a control approach that improves the force control robustness. A unified model of the human-robot system that considers the ankle impedance by a second-order dynamics subject to uncertainties in the stiffness, damping, and inertia parameters has been developed. Fixed, resistive, and passive operation modes of the robotics system were defined, where transition probabilities among the modes were modeled through a Markov chain. A robust regulator for Markovian jump linear systems was used in the design of the force control. Experimental results show the approach improves the impedance control performance. For comparison purposes, a standard H∞ force controller based on the fixed operation mode has also been designed. The Markovian control approach outperformed the H∞ control when all operation modes were taken into account.

  3. A Robust Inner and Outer Loop Control Method for Trajectory Tracking of a Quadrotor

    Science.gov (United States)

    Xia, Dunzhu; Cheng, Limei; Yao, Yanhong

    2017-01-01

    In order to achieve the complicated trajectory tracking of quadrotor, a geometric inner and outer loop control scheme is presented. The outer loop generates the desired rotation matrix for the inner loop. To improve the response speed and robustness, a geometric SMC controller is designed for the inner loop. The outer loop is also designed via sliding mode control (SMC). By Lyapunov theory and cascade theory, the closed-loop system stability is guaranteed. Next, the tracking performance is validated by tracking three representative trajectories. Then, the robustness of the proposed control method is illustrated by trajectory tracking in presence of model uncertainty and disturbances. Subsequently, experiments are carried out to verify the method. In the experiment, ultra wideband (UWB) is used for indoor positioning. Extended Kalman Filter (EKF) is used for fusing inertial measurement unit (IMU) and UWB measurements. The experimental results show the feasibility of the designed controller in practice. The comparative experiments with PD and PD loop demonstrate the robustness of the proposed control method. PMID:28925984

  4. A robust and high-performance queue management controller for large round trip time networks

    Science.gov (United States)

    Khoshnevisan, Ladan; Salmasi, Farzad R.

    2016-05-01

    Congestion management for transmission control protocol is of utmost importance to prevent packet loss within a network. This necessitates strategies for active queue management. The most applied active queue management strategies have their inherent disadvantages which lead to suboptimal performance and even instability in the case of large round trip time and/or external disturbance. This paper presents an internal model control robust queue management scheme with two degrees of freedom in order to restrict the undesired effects of large and small round trip time and parameter variations in the queue management. Conventional approaches such as proportional integral and random early detection procedures lead to unstable behaviour due to large delay. Moreover, internal model control-Smith scheme suffers from large oscillations due to the large round trip time. On the other hand, other schemes such as internal model control-proportional integral and derivative show excessive sluggish performance for small round trip time values. To overcome these shortcomings, we introduce a system entailing two individual controllers for queue management and disturbance rejection, simultaneously. Simulation results based on Matlab/Simulink and also Network Simulator 2 (NS2) demonstrate the effectiveness of the procedure and verify the analytical approach.

  5. Model-reference robust tuning of PID controllers

    CERN Document Server

    Alfaro, Victor M

    2016-01-01

    This book presents a unified methodology for the design of PID controllers that encompasses the wide range of different dynamics to be found in industrial processes. This is extended to provide a coherent way of dealing with the tuning of PID controllers. The particular method at the core of the book is the so-called model-reference robust tuning (MoReRT), developed by the authors. MoReRT constitutes a novel and powerful way of thinking of a robust design and taking into account the usual design trade-offs encountered in any control design problem. The book starts by presenting the different two-degree-of-freedom PID control algorithm variations and their conversion relations as well as the indexes used for performance, robustness and fragility evaluation:the bases of the proposed model. Secondly, the MoReRT design methodology and normalized controlled process models and controllers used in the design are described in order to facilitate the formulation of the different design problems and subsequent derivati...

  6. Secure Dynamic access control scheme of PHR in cloud computing.

    Science.gov (United States)

    Chen, Tzer-Shyong; Liu, Chia-Hui; Chen, Tzer-Long; Chen, Chin-Sheng; Bau, Jian-Guo; Lin, Tzu-Ching

    2012-12-01

    With the development of information technology and medical technology, medical information has been developed from traditional paper records into electronic medical records, which have now been widely applied. The new-style medical information exchange system "personal health records (PHR)" is gradually developed. PHR is a kind of health records maintained and recorded by individuals. An ideal personal health record could integrate personal medical information from different sources and provide complete and correct personal health and medical summary through the Internet or portable media under the requirements of security and privacy. A lot of personal health records are being utilized. The patient-centered PHR information exchange system allows the public autonomously maintain and manage personal health records. Such management is convenient for storing, accessing, and sharing personal medical records. With the emergence of Cloud computing, PHR service has been transferred to storing data into Cloud servers that the resources could be flexibly utilized and the operation cost can be reduced. Nevertheless, patients would face privacy problem when storing PHR data into Cloud. Besides, it requires a secure protection scheme to encrypt the medical records of each patient for storing PHR into Cloud server. In the encryption process, it would be a challenge to achieve accurately accessing to medical records and corresponding to flexibility and efficiency. A new PHR access control scheme under Cloud computing environments is proposed in this study. With Lagrange interpolation polynomial to establish a secure and effective PHR information access scheme, it allows to accurately access to PHR with security and is suitable for enormous multi-users. Moreover, this scheme also dynamically supports multi-users in Cloud computing environments with personal privacy and offers legal authorities to access to PHR. From security and effectiveness analyses, the proposed PHR access

  7. Robust broadcast-communication control of electric vehicle charging

    Energy Technology Data Exchange (ETDEWEB)

    Chertkov, Michael [Los Alamos National Laboratory; Turitsyn, Konstantin [Los Alamos National Laboratory; Sulc, Petr [Los Alamos National Laboratory; Backhaus, Scott [Los Alamos National Laboratory

    2010-01-01

    The anticipated increase in the number of plug-in electric vehicles (EV) will put additional strain on electrical distribution circuits. Many control schemes have been proposed to control EV charging. Here, we develop control algorithms based on randomized EV charging start times and simple one-way broadcast communication allowing for a time delay between communication events. Using arguments from queuing theory and statistical analysis, we seek to maximize the utilization of excess distribution circuit capacity while keeping the probability of a circuit overload negligible.

  8. A stable and robust calibration scheme of the log-periodic power law model

    Science.gov (United States)

    Filimonov, V.; Sornette, D.

    2013-09-01

    We present a simple transformation of the formulation of the log-periodic power law formula of the Johansen-Ledoit-Sornette (JLS) model of financial bubbles that reduces it to a function of only three nonlinear parameters. The transformation significantly decreases the complexity of the fitting procedure and improves its stability tremendously because the modified cost function is now characterized by good smooth properties with in general a single minimum in the case where the model is appropriate to the empirical data. We complement the approach with an additional subordination procedure that slaves two of the nonlinear parameters to the most crucial nonlinear parameter, the critical time tc, defined in the JLS model as the end of the bubble and the most probable time for a crash to occur. This further decreases the complexity of the search and provides an intuitive representation of the results of the calibration. With our proposed methodology, metaheuristic searches are not longer necessary and one can resort solely to rigorous controlled local search algorithms, leading to a dramatic increase in efficiency. Empirical tests on the Shanghai Composite index (SSE) from January 2007 to March 2008 illustrate our findings.

  9. Robust Adaptive Speed Control of Induction Motor Drives

    DEFF Research Database (Denmark)

    Bidstrup, N.

    This thesis concerns speed control of current vector controlled induction motor drives (CVC drives). The CVC drive is an existing prototype drive developed by Danfoss A/S, Transmission Division. Practical tests have revealed that the open loop dynamical properties of the CVC drive are highly......, (LS) identification and generalized predictive control (GPC) has been implemented and tested on the CVC drive. Allthough GPC is a robust control method, it was not possible to maintain specified controller performance in the entire operating range. This was the main reason for investigating truly...... adaptive speed control of the CVC drive. A direct truly adaptive speed controller has been implemented. The adaptive controller is a moving Average Self-Tuning Regulator which is abbreviated MASTR throughout the thesis. Two practical implementations of this controller were proposed. They were denoted MASTR...

  10. Analysis and design of robust decentralized controllers for nonlinear systems

    Energy Technology Data Exchange (ETDEWEB)

    Schoenwald, D.A.

    1993-07-01

    Decentralized control strategies for nonlinear systems are achieved via feedback linearization techniques. New results on optimization and parameter robustness of non-linear systems are also developed. In addition, parametric uncertainty in large-scale systems is handled by sensitivity analysis and optimal control methods in a completely decentralized framework. This idea is applied to alleviate uncertainty in friction parameters for the gimbal joints on Space Station Freedom. As an example of decentralized nonlinear control, singular perturbation methods and distributed vibration damping are merged into a control strategy for a two-link flexible manipulator.

  11. Turbulent boundary layer under the control of different schemes

    Science.gov (United States)

    Qiao, Z. X.; Zhou, Y.; Wu, Z.

    2017-06-01

    This work explores experimentally the control of a turbulent boundary layer over a flat plate based on wall perturbation generated by piezo-ceramic actuators. Different schemes are investigated, including the feed-forward, the feedback, and the combined feed-forward and feedback strategies, with a view to suppressing the near-wall high-speed events and hence reducing skin friction drag. While the strategies may achieve a local maximum drag reduction slightly less than their counterpart of the open-loop control, the corresponding duty cycles are substantially reduced when compared with that of the open-loop control. The results suggest a good potential to cut down the input energy under these control strategies. The fluctuating velocity, spectra, Taylor microscale and mean energy dissipation are measured across the boundary layer with and without control and, based on the measurements, the flow mechanism behind the control is proposed.

  12. Turbulent boundary layer under the control of different schemes.

    Science.gov (United States)

    Qiao, Z X; Zhou, Y; Wu, Z

    2017-06-01

    This work explores experimentally the control of a turbulent boundary layer over a flat plate based on wall perturbation generated by piezo-ceramic actuators. Different schemes are investigated, including the feed-forward, the feedback, and the combined feed-forward and feedback strategies, with a view to suppressing the near-wall high-speed events and hence reducing skin friction drag. While the strategies may achieve a local maximum drag reduction slightly less than their counterpart of the open-loop control, the corresponding duty cycles are substantially reduced when compared with that of the open-loop control. The results suggest a good potential to cut down the input energy under these control strategies. The fluctuating velocity, spectra, Taylor microscale and mean energy dissipation are measured across the boundary layer with and without control and, based on the measurements, the flow mechanism behind the control is proposed.

  13. Designing robust control-based HIV-treatment

    Directory of Open Access Journals (Sweden)

    Fredy Andrés Olarte Dussán

    2008-05-01

    Full Text Available Designing a robust control-based treatment for human immunodeficiency virus (HIV-infected patients was studied. The dynamics of the immune system’s response to infection was modelled using a 5th order nonlinear model with separate efficacy coefficients for protease inhibitor (PIs and reverse transcriptase inhibitors (RTIs. The immune res-ponse has been represented as an uncertain system due to errors in parameter estimation and the existence of un-modelled dynamics. A polytopic system was constructed incorporating all possible system parameter values. A con-trol system was designed using robust pole location techniques stabilising the polytopic system around an equilibrium point having a low viral load. Numerical simulation results (including the organism’s pharmacokinetical response to anti-retroviral drugs showed that the control law could lead to long-term stable conditions, even in extreme cases.

  14. Robust guaranteed cost tracking control of quadrotor UAV with uncertainties.

    Science.gov (United States)

    Xu, Zhiwei; Nian, Xiaohong; Wang, Haibo; Chen, Yinsheng

    2017-07-01

    In this paper, a robust guaranteed cost controller (RGCC) is proposed for quadrotor UAV system with uncertainties to address set-point tracking problem. A sufficient condition of the existence for RGCC is derived by Lyapunov stability theorem. The designed RGCC not only guarantees the whole closed-loop system asymptotically stable but also makes the quadratic performance level built for the closed-loop system have an upper bound irrespective to all admissible parameter uncertainties. Then, an optimal robust guaranteed cost controller is developed to minimize the upper bound of performance level. Simulation results verify the presented control algorithms possess small overshoot and short setting time, with which the quadrotor has ability to perform set-point tracking task well. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  15. A Robust Cooperated Control Method with Reinforcement Learning and Adaptive H∞ Control

    Science.gov (United States)

    Obayashi, Masanao; Uchiyama, Shogo; Kuremoto, Takashi; Kobayashi, Kunikazu

    This study proposes a robust cooperated control method combining reinforcement learning with robust control to control the system. A remarkable characteristic of the reinforcement learning is that it doesn't require model formula, however, it doesn't guarantee the stability of the system. On the other hand, robust control system guarantees stability and robustness, however, it requires model formula. We employ both the actor-critic method which is a kind of reinforcement learning with minimal amount of computation to control continuous valued actions and the traditional robust control, that is, H∞ control. The proposed system was compared method with the conventional control method, that is, the actor-critic only used, through the computer simulation of controlling the angle and the position of a crane system, and the simulation result showed the effectiveness of the proposed method.

  16. Robust Sliding Mode Control of Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems

    Directory of Open Access Journals (Sweden)

    Guangping Zhuo

    2016-12-01

    Full Text Available The subject of this paper pertains to sliding mode control and its application in nonlinear electrical power systems as seen in wind energy conversion systems. Due to the robustness in dealing with unmodeled system dynamics, sliding mode control has been widely used in electrical power system applications. This paper presents first and high order sliding mode control schemes for permanent magnet synchronous generator-based wind energy conversion systems. The application of these methods for control using dynamic models of the d-axis and q-axis currents, as well as those of the high speed shaft rotational speed show a high level of efficiency in power extraction from a varying wind resource. Computer simulation results have shown the efficacy of the proposed sliding mode control approaches.

  17. Adaptive Sliding Mode Robust Control for Virtual Compound-Axis Servo System

    Directory of Open Access Journals (Sweden)

    Yan Ren

    2013-01-01

    Full Text Available A structure mode of virtual compound-axis servo system is proposed to improve the tracking accuracy of the ordinary optoelectric tracking platform. It is based on the structure and principles of compound-axis servo system. A hybrid position control scheme combining the PD controller and feed-forward controller is used in subsystem to track the tracking error of the main system. This paper analyzes the influences of the equivalent disturbance in main system and proposes an adaptive sliding mode robust control method based on the improved disturbance observer. The sliding mode technique helps this disturbance observer to deal with the uncompensated disturbance in high frequency by making use of the rapid switching control value, which is based on the subtle error of disturbance estimation. Besides, the high-frequency chattering is alleviated effectively in this proposal. The effectiveness of the proposal is confirmed by experiments on optoelectric tracking platform.

  18. The Robust Control Mixer Method for Reconfigurable Control Design By Using Model Matching Strategy

    DEFF Research Database (Denmark)

    Yang, Z.; Blanke, Mogens; Verhagen, M.

    2001-01-01

    This paper proposes a robust reconfigurable control synthesis method based on the combination of the control mixer method and robust H1 con- trol techniques through the model-matching strategy. The control mixer modules are extended from the conventional matrix-form into the LTI sys- tem form. By...... of one space robot arm system subjected to failures....

  19. Microgrid Stability Controller Based on Adaptive Robust Total SMC

    DEFF Research Database (Denmark)

    Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.

    2015-01-01

    This paper presents a microgrid stability controller (MSC) in order to provide existing DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics...... and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC) system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external disturbances...

  20. Robust Control with Enlaeged Interval of Uncertain Parameters

    Directory of Open Access Journals (Sweden)

    Marek Keresturi

    2002-01-01

    Full Text Available Robust control is advantageous for systems with defined interval of uncertain parameters. This can be substantially enlarged dividing it into a few sub-intervals. Corresponding controllers for each of them may be set after approximate identification of some uncertain plant parameters. The paper deals with application of the pole region assignment method for position control of the crane crab. The same track form is required for uncertain burden mass and approximate value of rope length. Measurement of crab position and speed is supposed, burden deviation angle is observed. Simulation results have verified feasibility of this design procedure.

  1. Robust Performance And Dissipation of Stochastic Control Systems

    DEFF Research Database (Denmark)

    Thygesen, Uffe Høgsbro

    and topology on the space of supply rates. For instance, we give conditions under which the available storage is a continuous convex function of the supply rate. Dissipation theory in the existing literature applies only to deterministic systems. This is unfortunate since robust control applications typically...... also contain uncertainty which is better modelled in a probabilistic framework, such as measurement noise. This motivates an extension of the theory of dissipative dynamic systems to stochastic systems. This dissertation presents such an extension: We propose a definition and generalize fundamental...... in terms of dissipation, after which we give sufficient conditions for these requirements to be robust towards multi-dissipative perturbations. A final contribution of the dissertation concerns the problem of simultaneous H-infinity control of a finite number of linear time invariant plants. This problem...

  2. Less Conservative Optimal Robust Control of a 3-DOF Helicopter

    Directory of Open Access Journals (Sweden)

    L. F. S. Buzachero

    2015-01-01

    Full Text Available This work proposes an improved technique for design and optimization of robust controllers norm for uncertain linear systems, with state feedback, including the possibility of time-varying the uncertainty. The synthesis techniques used are based on LMIs (linear matrix inequalities formulated on the basis of Lyapunov’s stability theory, using Finsler’s lemma. The design has used the addition of the decay rate restriction, including a parameter γ in the LMIs, responsible for decreasing the settling time of the feedback system. Qualitative and quantitative comparisons were made between methods of synthesis and optimization of the robust controllers norm, seeking alternatives with lower cost and better performance that meet the design restrictions. A practical application illustrates the efficiency of the proposed method with a failure purposely inserted in the system.

  3. Robust Speed Tracking of Induction Motors: An Arduino-Implemented Intelligent Control Approach

    Directory of Open Access Journals (Sweden)

    Tan-Jan Ho

    2018-01-01

    Full Text Available To feasibly achieve economical and satisfactory robust velocity tracking of an induction machine (IM, we propose an Arduino-implemented intelligent speed controller. Because a voltage/frequency controlled IM framework is simple and well suited for being controlled by the proposed speed controller, it is adopted herein. Taking into account easy implementation and good performance, we design the controller using a modified Ziegler-Nichols PID (modified Z-N PID and a fuzzy logic controller (FLC. The modified Z-N PID and the FLC are connected in tandem. The latter is designed based on the output signal of the former for adaptively yielding adequate torque commands. Experimental results of IM velocity tracking controlled by our PC-based and Arduino-based speed controllers consistently show that the proposed design scheme can yield remarkable tracking performance and robustness. In addition, it is demonstrated that the proposed Arduino-implemented controller is not only viable but also effective in terms of cost, size and tracking performance.

  4. Robust combined position and formation control for marine surface craft

    DEFF Research Database (Denmark)

    Ihle, Ivar-Andre F.; Jouffroy, Jerome; Fossen, Thor I.

    that affect each vessel and to disturbances that affect the inter-vessel relationships e.g. communication noise. Next, we prove ISS of a formation where at least one vessel is in closed loop with, a class of position control laws, in addition to the formation control law. This class encompass control laws......We consider the robustness properties of a formation control system for marine surface vessels. Intervessel constraint functions are stabilized to achieve the desired formation configuration. We show that the formation dynamics is Input-to-State Stable (ISS) to both environmental perturbations...... for point stabilization or path following. Hence, the designer can utilize previously developed controllers for single vessels in a formation control setting. A formation of three tugboats where one is in closed loop with a path following controller is simulated to verify the theoretical results....

  5. Adaptive and Robust Sliding Mode Position Control of IPMSM Drives

    Directory of Open Access Journals (Sweden)

    ZAKY, M.

    2017-02-01

    Full Text Available This paper proposes an adaptive and robust sliding mode control (SMC for the position control of Interior Permanent Magnet Synchronous Motor (IPMSM drives. A switching surface of SMC is designed using a Linear Quadratic Regulator (LQR technique to simultaneously control the tracking trajectory and load torque changes. The quadratic optimal control method is used to select the state feedback control gain that constitutes the system dynamic performance under uncertainties and disturbances. Feedback and switching gains are selected to satisfy both stability and fast convergence of the IPMSM. Matlab/Simulink is used to build the drive system. Experimental implementation of the IPMSM drive is carried out using DSP-DS1102 control board. The efficacy of the proposed position control method is validated using theoretical analysis and simulation and experimental results.

  6. Planning Framework for Mesolevel Optimization of Urban Runoff Control Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Qianqian; Blohm, Andrew; Liu, Bo

    2017-04-01

    A planning framework is developed to optimize runoff control schemes at scales relevant for regional planning at an early stage. The framework employs less sophisticated modeling approaches to allow a practical application in developing regions with limited data sources and computing capability. The methodology contains three interrelated modules: (1)the geographic information system (GIS)-based hydrological module, which aims at assessing local hydrological constraints and potential for runoff control according to regional land-use descriptions; (2)the grading module, which is built upon the method of fuzzy comprehensive evaluation. It is used to establish a priority ranking system to assist the allocation of runoff control targets at the subdivision level; and (3)the genetic algorithm-based optimization module, which is included to derive Pareto-based optimal solutions for mesolevel allocation with multiple competing objectives. The optimization approach describes the trade-off between different allocation plans and simultaneously ensures that all allocation schemes satisfy the minimum requirement on runoff control. Our results highlight the importance of considering the mesolevel allocation strategy in addition to measures at macrolevels and microlevels in urban runoff management. (C) 2016 American Society of Civil Engineers.

  7. Study on noise prediction model and control schemes for substation.

    Science.gov (United States)

    Chen, Chuanmin; Gao, Yang; Liu, Songtao

    2014-01-01

    With the government's emphasis on environmental issues of power transmission and transformation project, noise pollution has become a prominent problem now. The noise from the working transformer, reactor, and other electrical equipment in the substation will bring negative effect to the ambient environment. This paper focuses on using acoustic software for the simulation and calculation method to control substation noise. According to the characteristics of the substation noise and the techniques of noise reduction, a substation's acoustic field model was established with the SoundPLAN software to predict the scope of substation noise. On this basis, 4 reasonable noise control schemes were advanced to provide some helpful references for noise control during the new substation's design and construction process. And the feasibility and application effect of these control schemes can be verified by using the method of simulation modeling. The simulation results show that the substation always has the problem of excessive noise at boundary under the conventional measures. The excess noise can be efficiently reduced by taking the corresponding noise reduction methods.

  8. Robust coordinated control of a dual-arm space robot

    Science.gov (United States)

    Shi, Lingling; Kayastha, Sharmila; Katupitiya, Jay

    2017-09-01

    Dual-arm space robots are more capable of implementing complex space tasks compared with single arm space robots. However, the dynamic coupling between the arms and the base will have a serious impact on the spacecraft attitude and the hand motion of each arm. Instead of considering one arm as the mission arm and the other as the balance arm, in this work two arms of the space robot perform as mission arms aimed at accomplishing secure capture of a floating target. The paper investigates coordinated control of the base's attitude and the arms' motion in the task space in the presence of system uncertainties. Two types of controllers, i.e. a Sliding Mode Controller (SMC) and a nonlinear Model Predictive Controller (MPC) are verified and compared with a conventional Computed-Torque Controller (CTC) through numerical simulations in terms of control accuracy and system robustness. Both controllers eliminate the need to linearly parameterize the dynamic equations. The MPC has been shown to achieve performance with higher accuracy than CTC and SMC in the absence of system uncertainties under the condition that they consume comparable energy. When the system uncertainties are included, SMC and CTC present advantageous robustness than MPC. Specifically, in a case where system inertia increases, SMC delivers higher accuracy than CTC and costs the least amount of energy.

  9. Robust Optimal Adaptive Trajectory Tracking Control of Quadrotor Helicopter

    Directory of Open Access Journals (Sweden)

    M. Navabi

    Full Text Available Abstract This paper focuses on robust optimal adaptive control strategy to deal with tracking problem of a quadrotor unmanned aerial vehicle (UAV in presence of parametric uncertainties, actuator amplitude constraints, and unknown time-varying external disturbances. First, Lyapunov-based indirect adaptive controller optimized by particle swarm optimization (PSO is developed for multi-input multi-output (MIMO nonlinear quadrotor to prevent input constraints violation, and then disturbance observer-based control (DOBC technique is aggregated with the control system to attenuate the effects of disturbance generated by an exogenous system. The performance of synthesis control method is evaluated by a new performance index function in time-domain, and the stability analysis is carried out using Lyapunov theory. Finally, illustrative numerical simulations are conducted to demonstrate the effectiveness of the presented approach in altitude and attitude tracking under several conditions, including large time-varying uncertainty, exogenous disturbance, and control input constraints.

  10. Robust adaptive precision motion control of hydraulic actuators with valve dead-zone compensation.

    Science.gov (United States)

    Deng, Wenxiang; Yao, Jianyong; Ma, Dawei

    2017-09-01

    This paper addresses the high performance motion control of hydraulic actuators with parametric uncertainties, unmodeled disturbances and unknown valve dead-zone. By constructing a smooth dead-zone inverse, a robust adaptive controller is proposed via backstepping method, in which adaptive law is synthesized to deal with parametric uncertainties and a continuous nonlinear robust control law to suppress unmodeled disturbances. Since the unknown dead-zone parameters can be estimated by adaptive law and then the effect of dead-zone can be compensated effectively via inverse operation, improved tracking performance can be expected. In addition, the disturbance upper bounds can also be updated online by adaptive laws, which increases the controller operability in practice. The Lyapunov based stability analysis shows that excellent asymptotic output tracking with zero steady-state error can be achieved by the developed controller even in the presence of unmodeled disturbance and unknown valve dead-zone. Finally, the proposed control strategy is experimentally tested on a servovalve controlled hydraulic actuation system subjected to an artificial valve dead-zone. Comparative experimental results are obtained to illustrate the effectiveness of the proposed control scheme. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Sensorless AC electric motor control robust advanced design techniques and applications

    CERN Document Server

    Glumineau, Alain

    2015-01-01

    This monograph shows the reader how to avoid the burdens of sensor cost, reduced internal physical space, and system complexity in the control of AC motors. Many applications fields—electric vehicles, wind- and wave-energy converters and robotics, among them—will benefit. Sensorless AC Electric Motor Control describes the elimination of physical sensors and their replacement with observers, i.e., software sensors. Robustness is introduced to overcome problems associated with the unavoidable imperfection of knowledge of machine parameters—resistance, inertia, and so on—encountered in real systems. The details of a large number of speed- and/or position-sensorless ideas for different types of permanent-magnet synchronous motors and induction motors are presented along with several novel observer designs for electrical machines. Control strategies are developed using high-order, sliding-mode and quasi-continuous-sliding-mode techniques and two types of observer–controller schemes based on backstepping ...

  12. Robust model predictive control of hybrid transmissions; Robuste Modellpraediktive Regelung fuer Hybridgetriebe

    Energy Technology Data Exchange (ETDEWEB)

    Beck, R. [RWTH Aachen (Germany). Inst. fuer Regelungstechnik; Saenger Zetina, S.; Neiss, K. [DaimlerChrysler Corp., Troy, MI (United States); Bollig, A. [Siemens AG, Muenchen (Germany)

    2007-07-15

    Hybrid electric vehicles increasingly gain importance mainly due to the potential fuel saving but also because of the additional agility achieved by the increased peak torques during boosting. An important aspect of a hybrid architecture is the transition between pure electric and hybrid operation, which is exemplarily investigated in a flexible hybrid transmission under a parallel engagement configuration. A clutch which separates the transmission input side (engine side) from the rest of the drivetrain is engaged in order to achieve the transition. A noticeable jerk during the engagement process or an interruption of the drive torque cannot be tolerated since the driving comfort must not be reduced. Special attention was given to the robustness of the controller, since the transition has to be carried out reliably and comfortably under varying vehicle properties and drive conditions. (orig.)

  13. Segmentation Scheme for Safety Enhancement of Engineered Safety Features Component Control System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sangseok; Sohn, Kwangyoung [Korea Reliability Technology and System, Daejeon (Korea, Republic of); Lee, Junku; Park, Geunok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    Common Caused Failure (CCF) or undetectable failure would adversely impact safety functions of ESF-CCS in the existing nuclear power plants. We propose the segmentation scheme to solve these problems. Main function assignment to segments in the proposed segmentation scheme is based on functional dependency and critical function success path by using the dependency depth matrix. The segment has functional independence and physical isolation. The segmentation structure is that prohibit failure propagation to others from undetectable failures. Therefore, the segmentation system structure has robustness to undetectable failures. The segmentation system structure has functional diversity. The specific function in the segment defected by CCF, the specific function could be maintained by diverse control function that assigned to other segments. Device level control signals and system level control signals are separated and also control signal and status signals are separated due to signal transmission paths are allocated independently based on signal type. In this kind of design, single device failure or failures on signal path in the channel couldn't result in the loss of all segmented functions simultaneously. Thus the proposed segmentation function is the design scheme that improves availability of safety functions. In conventional ESF-CCS, the single controller generates the signal to control the multiple safety functions, and the reliability is achieved by multiplication within the channel. This design has a drawback causing the loss of multiple functions due to the CCF (Common Cause Failure) and single failure Heterogeneous controller guarantees the diversity ensuring the execution of safety functions against the CCF and single failure, but requiring a lot of resources like manpower and cost. The segmentation technology based on the compartmentalization and functional diversification decreases the CCF and single failure nonetheless the identical types of

  14. Robust positioning control of pneumatic servo system with pressure control loop

    OpenAIRE

    Noritsugu, Toshiro; Takaiwa, Masahiro

    1995-01-01

    The goal of this paper is to attain a robust positioning control of a pneumatic driving system. A positioning control system positively focusing on the pressure control is investigated from the view that the pressure control is indispensable for improvement of control performances. A disturbance observer is employed to improve the pressure response and compensate the influence of friction force and parameter change. Consequently the improvements of robustness against payload and of positionin...

  15. A new control scheme for PID load frequency controller of single-area and multi-area power systems.

    Science.gov (United States)

    Padhan, Dola Gobinda; Majhi, Somanath

    2013-03-01

    A new control structure with a tuning method to design a PID load frequency controller for power systems is presented. Initially, the controller is designed for single area power system, then it is extended to multi-area case. The controller parameters are obtained by expanding controller transfer function using Laurent series. Relay based identification technique is adopted to estimate power system dynamics. Robustness studies on stability and performance are provided, with respect to uncertainties in the plant parameters. The proposed scheme ensures that overall system remains asymptotically stable for all bounded uncertainties and for system oscillations. Simulation results show the feasibility of the approach and the proposed method improves the load disturbance rejection performance significantly even in the presence of the uncertainties in plant parameters. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  16. A Jacobian singularity based robust controller design for structured uncertainty

    Science.gov (United States)

    Brown, Brandon

    Any real system will have differences between the mathematical model response and the response of the true system it represents. These differences can come from external disturbances, incomplete modeling of the dynamics (unstructured uncertainty) or simply incorrect or changing parameter values (structured uncertainty) in the model. Sources of unstructured uncertainty are unavoidable in real systems, so a controller design must always consider robustness to these effects. In many cases, when the sources of structured uncertainty are addressed as another source of unstructured uncertainty, the resulting controller design is conservative. By accurately addressing and designing a controller for the structured uncertainty, large benefits in the controller performance can be generated since the conservative bound is reduced. The classical approach to output shaping of a system involves a feedback loop since this architecture is more robust to differences between the mathematical model and the true system. This dissertation will present an approach to design a feedback controller which is robust to structured uncertainties in a plant, in an accurate and minimal way. The approach begins by identifying a critical set of system parameters which will be proven to represent the full set of system parameters in the Nyquist plane. This critical set is populated by all parameter vectors which satisfy a developed deficiency condition and is the minimal set which will contribute to the Nyquist plane portraits. The invariance of this critical set to control structure is shown explicitly. An improvement of previous work is the addition of a numerical solution technique which guarantees that all critical points are found. The presented approach will allow for the designer set minimum relative stability margins, such as gain and phase margins, which previous work could not compute accurately or with confidence of the results. A robust controller is designed with respect to this

  17. COA based robust output feedback UPFC controller design

    Energy Technology Data Exchange (ETDEWEB)

    Shayeghi, H., E-mail: hshayeghi@gmail.co [Technical Engineering Department, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Shayanfar, H.A. [Center of Excellence for Power System Automation and Operation, Electrical Engineering Department, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Jalilzadeh, S.; Safari, A. [Technical Engineering Department, Zanjan University, Zanjan (Iran, Islamic Republic of)

    2010-12-15

    In this paper, a novel method for the design of output feedback controller for unified power flow controller (UPFC) using chaotic optimization algorithm (COA) is developed. Chaotic optimization algorithms, which have the features of easy implementation, short execution time and robust mechanisms of escaping from the local optimum, is a promising tool for the engineering applications. The selection of the output feedback gains for the UPFC controllers is converted to an optimization problem with the time domain-based objective function which is solved by a COA based on Lozi map. Since chaotic mapping enjoys certainty, ergodicity and the stochastic property, the proposed chaotic optimization problem introduces chaos mapping using Lozi map chaotic sequences which increases its convergence rate and resulting precision. To ensure the robustness of the proposed stabilizers, the design process takes into account a wide range of operating conditions and system configurations. The effectiveness of the proposed controller for damping low frequency oscillations is tested and demonstrated through non-linear time-domain simulation and some performance indices studies. The results analysis reveals that the designed COA based output feedback UPFC damping controller has an excellent capability in damping power system low frequency oscillations and enhance greatly the dynamic stability of the power systems.

  18. A robust decentralized load frequency controller for interconnected power systems.

    Science.gov (United States)

    Dong, Lili; Zhang, Yao; Gao, Zhiqiang

    2012-05-01

    A novel design of a robust decentralized load frequency control (LFC) algorithm is proposed for an inter-connected three-area power system, for the purpose of regulating area control error (ACE) in the presence of system uncertainties and external disturbances. The design is based on the concept of active disturbance rejection control (ADRC). Estimating and mitigating the total effect of various uncertainties in real time, ADRC is particularly effective against a wide range of parameter variations, model uncertainties, and large disturbances. Furthermore, with only two tuning parameters, the controller provides a simple and easy-to-use solution to complex engineering problems in practice. Here, an ADRC-based LFC solution is developed for systems with turbines of various types, such as non-reheat, reheat, and hydraulic. The simulation results verified the effectiveness of the ADRC, in comparison with an existing PI-type controller tuned via genetic algorithm linear matrix inequalities (GALMIs). The comparison results show the superiority of the proposed solution. Moreover, the stability and robustness of the closed-loop system is studied using frequency-domain analysis. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  19. A secure and robust password-based remote user authentication scheme using smart cards for the integrated EPR information system.

    Science.gov (United States)

    Das, Ashok Kumar

    2015-03-01

    An integrated EPR (Electronic Patient Record) information system of all the patients provides the medical institutions and the academia with most of the patients' information in details for them to make corrective decisions and clinical decisions in order to maintain and analyze patients' health. In such system, the illegal access must be restricted and the information from theft during transmission over the insecure Internet must be prevented. Lee et al. proposed an efficient password-based remote user authentication scheme using smart card for the integrated EPR information system. Their scheme is very efficient due to usage of one-way hash function and bitwise exclusive-or (XOR) operations. However, in this paper, we show that though their scheme is very efficient, their scheme has three security weaknesses such as (1) it has design flaws in password change phase, (2) it fails to protect privileged insider attack and (3) it lacks the formal security verification. We also find that another recently proposed Wen's scheme has the same security drawbacks as in Lee at al.'s scheme. In order to remedy these security weaknesses found in Lee et al.'s scheme and Wen's scheme, we propose a secure and efficient password-based remote user authentication scheme using smart cards for the integrated EPR information system. We show that our scheme is also efficient as compared to Lee et al.'s scheme and Wen's scheme as our scheme only uses one-way hash function and bitwise exclusive-or (XOR) operations. Through the security analysis, we show that our scheme is secure against possible known attacks. Furthermore, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool and show that our scheme is secure against passive and active attacks.

  20. Robust stability in constrained predictive control through the Youla parameterisations

    DEFF Research Database (Denmark)

    Thomsen, Sven Creutz; Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2011-01-01

    In this article we take advantage of the primary and dual Youla parameterisations to set up a soft constrained model predictive control (MPC) scheme. In this framework it is possible to guarantee stability in face of norm-bounded uncertainties. Under special conditions guarantees are also given f...... arguments on the loop consisting of the primary and dual Youla parameter. This is included in the MPC optimisation as a constraint on the induced gain of the optimisation variable. We illustrate the method with a numerical simulation example....

  1. Robust Adaptive Fuzzy Design for Ship Linear-tracking Control with Input Saturation

    Directory of Open Access Journals (Sweden)

    Yancai Hu

    2017-04-01

    Full Text Available A robust adaptive control approach is proposed for underactuated surface ship linear path-tracking control system based on the backstepping control method and Lyapunov stability theory. By employing T-S fuzzy system to approximate nonlinear uncertainties of the control system, the proposed scheme is developed by combining “dynamic surface control” (DSC and “minimal learning parameter” (MLP techniques. The substantial problems of “explosion of complexity” and “dimension curse” existed in the traditional backstepping technique are circumvented, and it is convenient to implement in applications. In addition, an auxiliary system is developed to deal with the effect of input saturation constraints. The control algorithm avoids the singularity problem of controller and guarantees the stability of the closed-loop system. The tracking error converges to an arbitrarily small neighborhood. Finally, MATLAB simulation results are given from an application case of Dalian Maritime University training ship to demonstrate the effectiveness of the proposed scheme.

  2. Improving the Authentication Scheme and Access Control Protocol for VANETs

    Directory of Open Access Journals (Sweden)

    Wei-Chen Wu

    2014-11-01

    Full Text Available Privacy and security are very important in vehicular ad hoc networks (VANETs. VANETs are negatively affected by any malicious user’s behaviors, such as bogus information and replay attacks on the disseminated messages. Among various security threats, privacy preservation is one of the new challenges of protecting users’ private information. Existing authentication protocols to secure VANETs raise challenges, such as certificate distribution and reduction of the strong reliance on tamper-proof devices. In 2011, Yeh et al. proposed a PAACP: a portable privacy-preserving authentication and access control protocol in vehicular ad hoc networks. However, PAACP in the authorization phase is breakable and cannot maintain privacy in VANETs. In this paper, we present a cryptanalysis of an attachable blind signature and demonstrate that the PAACP’s authorized credential (AC is not secure and private, even if the AC is secretly stored in a tamper-proof device. An eavesdropper can construct an AC from an intercepted blind document. Any eavesdropper can determine who has which access privileges to access which service. For this reason, this paper copes with these challenges and proposes an efficient scheme. We conclude that an improving authentication scheme and access control protocol for VANETs not only resolves the problems that have appeared, but also is more secure and efficient.

  3. Enhanced robust fractional order proportional-plus-integral controller based on neural network for velocity control of permanent magnet synchronous motor.

    Science.gov (United States)

    Zhang, Bitao; Pi, YouGuo

    2013-07-01

    The traditional integer order proportional-integral-differential (IO-PID) controller is sensitive to the parameter variation or/and external load disturbance of permanent magnet synchronous motor (PMSM). And the fractional order proportional-integral-differential (FO-PID) control scheme based on robustness tuning method is proposed to enhance the robustness. But the robustness focuses on the open-loop gain variation of controlled plant. In this paper, an enhanced robust fractional order proportional-plus-integral (ERFOPI) controller based on neural network is proposed. The control law of the ERFOPI controller is acted on a fractional order implement function (FOIF) of tracking error but not tracking error directly, which, according to theory analysis, can enhance the robust performance of system. Tuning rules and approaches, based on phase margin, crossover frequency specification and robustness rejecting gain variation, are introduced to obtain the parameters of ERFOPI controller. And the neural network algorithm is used to adjust the parameter of FOIF. Simulation and experimental results show that the method proposed in this paper not only achieve favorable tracking performance, but also is robust with regard to external load disturbance and parameter variation. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  4. Adaptive robust fault tolerant control design for a class of nonlinear uncertain MIMO systems with quantization.

    Science.gov (United States)

    Ao, Wei; Song, Yongdong; Wen, Changyun

    2017-05-01

    In this paper, we investigate the adaptive control problem for a class of nonlinear uncertain MIMO systems with actuator faults and quantization effects. Under some mild conditions, an adaptive robust fault-tolerant control is developed to compensate the affects of uncertainties, actuator failures and errors caused by quantization, and a range of the parameters for these quantizers is established. Furthermore, a Lyapunov-like approach is adopted to demonstrate that the ultimately uniformly bounded output tracking error is guaranteed by the controller, and the signals of the closed-loop system are ensured to be bounded, even in the presence of at most m-q actuators stuck or outage. Finally, numerical simulations are provided to verify and illustrate the effectiveness of the proposed adaptive schemes. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Control system design for electrical stimulation in upper limb rehabilitation modelling, identification and robust performance

    CERN Document Server

    Freeman, Chris

    2016-01-01

    This book presents a comprehensive framework for model-based electrical stimulation (ES) controller design, covering the whole process needed to develop a system for helping people with physical impairments perform functional upper limb tasks such as eating, grasping and manipulating objects. The book first demonstrates procedures for modelling and identifying biomechanical models of the response of ES, covering a wide variety of aspects including mechanical support structures, kinematics, electrode placement, tasks, and sensor locations. It then goes on to demonstrate how complex functional activities of daily living can be captured in the form of optimisation problems, and extends ES control design to address this case. It then lays out a design methodology, stability conditions, and robust performance criteria that enable control schemes to be developed systematically and transparently, ensuring that they can operate effectively in the presence of realistic modelling uncertainty, physiological variation an...

  6. Robust tests for matched case-control genetic association studies

    Directory of Open Access Journals (Sweden)

    Fung Wing

    2010-10-01

    Full Text Available Abstract Background The Cochran-Armitage trend test (CATT is powerful in detecting association between a susceptible marker and a disease. This test, however, may suffer from a substantial loss of power when the underlying genetic model is unknown and incorrectly specified. Thus, it is useful to derive tests obtaining the plausible power against all common genetic models. For this purpose, the genetic model selection (GMS and genetic model exclusion (GME methods were proposed recently. Simulation results showed that GMS and GME can obtain the plausible power against three common genetic models while the overall type I error is well controlled. Results Although GMS and GME are powerful statistically, they could be seriously affected by known confounding factors such as gender, age and race. Therefore, in this paper, via comparing the difference of Hardy-Weinberg disequilibrium coefficients between the cases and the controls within each sub-population, we propose the stratified genetic model selection (SGMS and exclusion (SGME methods which could eliminate the effect of confounding factors by adopting a matching framework. Our goal in this paper is to investigate the robustness of the proposed statistics and compare them with other commonly used efficiency robust tests such as MAX3 and χ2 with 2 degrees of freedom (df test in matched case-control association designs through simulation studies. Conclusion Simulation results showed that if the mean genetic effect of the heterozygous genotype is between those of the two homozygous genotypes, then the proposed tests and MAX3 are preferred. Otherwise, χ2 with 2 df test may be used. To illustrate the robust procedures, the proposed tests are applied to a real matched pair case-control etiologic study of sarcoidosis.

  7. Bearingless Flywheel Systems, Winding and Control Schemes, and Sensorless Control

    Science.gov (United States)

    Jansen, Ralph H (Inventor); Trase, Larry M (Inventor); Dever, Timothy P (Inventor); Kascak, Peter E (Inventor); Kraft, Thomas G (Inventor)

    2016-01-01

    Flywheel systems are disclosed that provide increased energy density and operational effectiveness. A first bearingless motor and a second bearingless motor may be configured to simultaneously suspend the central rotor in a radial direction and to rotate the central rotor. However, certain implementations may have one motor or more than two motors, depending on the design. A plurality of the flywheel systems may be collectively controlled to perform community energy storage with higher storage capacities than individual flywheel systems.

  8. A robust adaptive load frequency control for micro-grids.

    Science.gov (United States)

    Khooban, Mohammad-Hassan; Niknam, Taher; Blaabjerg, Frede; Davari, Pooya; Dragicevic, Tomislav

    2016-11-01

    The goal of this study is to introduce a novel robust load frequency control (LFC) strategy for micro-grid(s) (MG(s)) in islanded mode operation. Admittedly, power generators in MG(s) cannot supply steady electric power output and sometimes cause unbalance between supply and demand. Battery energy storage system (BESS) is one of the effective solutions to these problems. Due to the high cost of the BESS, a new idea of Vehicle-to-Grid (V2G) is that a battery of Electric-Vehicle (EV) can be applied as a tantamount large-scale BESS in MG(s). As a result, a new robust control strategy for an islanded micro-grid (MG) is introduced that can consider electric vehicles׳ (EV(s)) effect. Moreover, in this paper, a new combination of the General Type II Fuzzy Logic Sets (GT2FLS) and the Modified Harmony Search Algorithm (MHSA) technique is applied for adaptive tuning of proportional-integral (PI) controller. Implementing General Type II Fuzzy Systems is computationally expensive. However, using a recently introduced α-plane representation, GT2FLS can be seen as a composition of several Interval Type II Fuzzy Logic Systems (IT2FLS) with a corresponding level of α for each. Real-data from an offshore wind farm in Sweden and solar radiation data in Aberdeen (United Kingdom) was used in order to examine the performance of the proposed novel controller. A comparison is made between the achieved results of Optimal Fuzzy-PI (OFPI) controller and those of Optimal Interval Type II Fuzzy-PI (IT2FPI) controller, which are of most recent advances in the area at hand. The Simulation results prove the successfulness and effectiveness of the proposed controller. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Efficient rate control scheme using modified inter-layer dependency ...

    Indian Academy of Sciences (India)

    In this paper, a spatial-resolutionratio-based MB mode decision scheme is proposed for spatially enhanced layers. The scheme uses the motion estimated at the base layer, to encode the respective MBs in the enhancement layers. The spatial–temporalsearch schemes at the enhancement layers are used to derive motion ...

  10. A Fault-tolerable Control Scheme for an Open-frame Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Huang Hai

    2014-05-01

    Full Text Available Open-frame is one of the major types of structures of Remote Operated Vehicles (ROV because it is easy to place sensors and operations equipment onboard. Firstly, this paper designed a petri-based recurrent neural network (PRFNN to improve the robustness with response to nonlinear characteristics and strong disturbance of an open-frame underwater vehicle. A threshold has been set in the third layer to reduce the amount of calculations and regulate the training process. The whole network convergence is guaranteed with the selection of learning rate parameters. Secondly, a fault tolerance control (FTC scheme is established with the optimal allocation of thrust. Infinity-norm optimization has been combined with 2-norm optimization to construct a bi-criteria primal-dual neural network FTC scheme. In the experiments and simulation, PRFNN outperformed fuzzy neural networks in motion control, while bi-criteria optimization outperformed 2-norm optimization in FTC, which demonstrates that the FTC controller can improve computational efficiency, reduce control errors, and implement fault tolerable thrust allocation.

  11. Developing e-course Robust Constrained PID Control

    Directory of Open Access Journals (Sweden)

    Peter Ťapák

    2011-04-01

    Full Text Available This paper informs about the latest development of the blended learning course Robust Constrained PID Control and describes in details problems faced in evaluating independent work of students with real time experiments that represent the main element of the applied “learning by doing” and “learning by experimenting” approach. Basic features of the developed system that evaluates consistency of student’s results with the measured experimental data and possibilities of further system expansion to automation of offering to student constructive feedback are discussed. Simultaneously, by comparing all data of the Matlab workspace the developed system serves although as an excellent anti-plagiarism tool.

  12. Robust algebraic image enhancement for intelligent control systems

    Science.gov (United States)

    Lerner, Bao-Ting; Morrelli, Michael

    1993-01-01

    Robust vision capability for intelligent control systems has been an elusive goal in image processing. The computationally intensive techniques a necessary for conventional image processing make real-time applications, such as object tracking and collision avoidance difficult. In order to endow an intelligent control system with the needed vision robustness, an adequate image enhancement subsystem capable of compensating for the wide variety of real-world degradations, must exist between the image capturing and the object recognition subsystems. This enhancement stage must be adaptive and must operate with consistency in the presence of both statistical and shape-based noise. To deal with this problem, we have developed an innovative algebraic approach which provides a sound mathematical framework for image representation and manipulation. Our image model provides a natural platform from which to pursue dynamic scene analysis, and its incorporation into a vision system would serve as the front-end to an intelligent control system. We have developed a unique polynomial representation of gray level imagery and applied this representation to develop polynomial operators on complex gray level scenes. This approach is highly advantageous since polynomials can be manipulated very easily, and are readily understood, thus providing a very convenient environment for image processing. Our model presents a highly structured and compact algebraic representation of grey-level images which can be viewed as fuzzy sets.

  13. Robust control of novel pendulum-type vibration isolation system

    Science.gov (United States)

    Tsai, Meng-Shiun; Sun, Yann-Shuoh; Liu, Chun-Hsieh

    2011-08-01

    A novel pendulum-type vibration isolation system is proposed consisting of three active cables with embedded piezoelectric actuators and a passive elastomer layer. The dynamic response of the isolation module in the vertical and horizontal directions is modeled using the Lagrangian approach. The validity of the dynamic model is confirmed by comparing the simulation results for the frequency response in the vertical and horizontal directions with the experimental results. An approximate model is proposed to take into account system uncertainties such as payload changes and hysteresis effects. A robust quantitative feedback theory (QFT)-based active controller is then designed to ensure that the active control can achieve a high level of disturbance rejection in the low-frequency range even under variable loading conditions. It is shown that the controller achieves average disturbance rejection of -14 dB in the 2-60 Hz bandwidth range and -35 dB at the resonance frequency. The experimental results confirm that the proposed system achieves a robust vibration isolation performance under the payload in the range of 40-60 kg.

  14. Stable, Robust Hybrid Zero Dynamics Control of Powered Lower-Limb Prostheses.

    Science.gov (United States)

    Martin, Anne E; Gregg, Robert D

    2017-08-01

    To improve the quality of life for lower-limb amputees, powered prostheses are being developed. Advanced control schemes from the field of bipedal robots, such as hybrid zero dynamics (HZD), may provide great performance. HZD-based control specifies the motion of the actuated joints using output functions to be zeroed, and the required torques are calculated using input-output linearization. For one-step periodic gaits, there is an analytic metric of stability. To apply HZD-based control on a powered prosthesis, several modifications must be made. Because the prosthesis and amputee are only connected via the socket, the prosthesis controller does not have access to the full state of the biped, which decentralizes the form of the input-output linearization. The differences between the amputated and contralateral sides result in a two-step periodic gait, which requires the orbital stability metric to be extended. In addition, because human gait is variable, the prosthesis controller must be robust to continuous moderate perturbations. This robustness is proved using local input-to-state stability and demonstrated with simulations of an above-knee amputee model.

  15. Gust Load Alleviation with Robust Control for a Flexible Wing

    Directory of Open Access Journals (Sweden)

    Xiang Liu

    2016-01-01

    Full Text Available Traditional methods for gust alleviation of aircraft are mostly proposed based on a specific flight condition. In this paper, robust control laws are designed for a large flexible wing with uncertainty in Mach number and dynamic pressure. To accurately describe the aeroelastic model over a large flight envelope, a nonlinear parameter-varying model is developed which is a function of both Mach number and dynamic pressure. Then a linear fractional transformation is established accordingly and a modified model order reduction technique is applied to reduce the size of the uncertainty block. The developed model, in which the statistic nature of the gust is considered by using the Dryden power spectral density function, enables the use of μ-synthesis procedures for controller design. The simulations show that the μ controller can always effectively reduce the wing root shear force and bending moment at a given range of Mach number and dynamic pressure.

  16. Density control in ITER: an iterative learning control and robust control approach

    Science.gov (United States)

    Ravensbergen, T.; de Vries, P. C.; Felici, F.; Blanken, T. C.; Nouailletas, R.; Zabeo, L.

    2018-01-01

    Plasma density control for next generation tokamaks, such as ITER, is challenging because of multiple reasons. The response of the usual gas valve actuators in future, larger fusion devices, might be too slow for feedback control. Both pellet fuelling and the use of feedforward-based control may help to solve this problem. Also, tight density limits arise during ramp-up, due to operational limits related to divertor detachment and radiative collapses. As the number of shots available for controller tuning will be limited in ITER, in this paper, iterative learning control (ILC) is proposed to determine optimal feedforward actuator inputs based on tracking errors, obtained in previous shots. This control method can take the actuator and density limits into account and can deal with large actuator delays. However, a purely feedforward-based density control may not be sufficient due to the presence of disturbances and shot-to-shot differences. Therefore, robust control synthesis is used to construct a robustly stabilizing feedback controller. In simulations, it is shown that this combined controller strategy is able to achieve good tracking performance in the presence of shot-to-shot differences, tight constraints, and model mismatches.

  17. A Comparison between Voltage and Reactive Power Feedback Schemes of DFIGs for Inter-Area Oscillation Damping Control

    Directory of Open Access Journals (Sweden)

    Kai Liao

    2017-08-01

    Full Text Available Reactive power modulation of wind power plants is an effective way to damp inter-area oscillation in wind power penetrated power systems. For doubly fed induction generator (DFIG based wind farms, there are two different ways to achieve reactive power modulation: one is via reactive power feedback control, and the other method is via voltage feedback control. While both of the control schemes are feasible, their effectiveness may differ, and there has not been a systematic comparison between them. This paper investigates the differences between these two feedback schemes for inter-area oscillation damping control. The principles of utilizing DFIG for damping control is introduced at first. Then, analytical techniques including the frequency domain analysis, μ -analysis and time domain analysis are used to systematically study the performance of the two control schemes against inter-area oscillation. The robustness of the control schemes with respect to the variety of system operation points is also studied. The results from this paper can provide an insight into the understatement of DFIG reactive modulation against oscillation and guidance for controller design.

  18. Robust Control of the Spatial Current Profile in the DIII-D Tokamak

    Science.gov (United States)

    Barton, J.; Schuster, E.; Walker, M. L.; Humphreys, D. A.

    2011-10-01

    Advanced tokamak operating scenarios, characterized by large noninductively driven plasma currents, typically require active regulation of a specific current density profile. Non-model-based control of the q profile has been tested at DIII-D. However, some present limitations of the controller motivate the design of a model-based controller that accounts for the dynamics of the whole q profile in response to the control actuators. A control-oriented model of the current profile evolution in DIII-D was recently developed and used to design feedforward control schemes. In order to reject the effects of external disturbances to the system, a feedback control input needs to be added to the feedforward input. In this work, we report on the design of a robust feedback controller, on the implementation of the combined model-based feedforward + feedback controller in the DIII-D Plasma Control System, and on the experimental validation of the combined controller in the DIII-D tokamak. Supported by the NSF CAREER award program ECCS-0645086 and the US DOE under DE-FG02-09ER55064 and DE-FC02-04ER54698.

  19. Genetic and Environmental Control of Neurodevelopmental Robustness in Drosophila.

    Directory of Open Access Journals (Sweden)

    David J Mellert

    Full Text Available Interindividual differences in neuronal wiring may contribute to behavioral individuality and affect susceptibility to neurological disorders. To investigate the causes and potential consequences of wiring variation in Drosophila melanogaster, we focused on a hemilineage of ventral nerve cord interneurons that exhibits morphological variability. We find that late-born subclasses of the 12A hemilineage are highly sensitive to genetic and environmental variation. Neurons in the second thoracic segment are particularly variable with regard to two developmental decisions, whereas its segmental homologs are more robust. This variability "hotspot" depends on Ultrabithorax expression in the 12A neurons, indicating variability is cell-intrinsic and under genetic control. 12A development is more variable and sensitive to temperature in long-established laboratory strains than in strains recently derived from the wild. Strains with a high frequency of one of the 12A variants also showed a high frequency of animals with delayed spontaneous flight initiation, whereas other wing-related behaviors did not show such a correlation and were thus not overtly affected by 12A variation. These results show that neurodevelopmental robustness is variable and under genetic control in Drosophila and suggest that the fly may serve as a model for identifying conserved gene pathways that stabilize wiring in stressful developmental environments. Moreover, some neuronal lineages are variation hotspots and thus may be more amenable to evolutionary change.

  20. Control Engineering Methods for the Design of Robust Behavioral Treatments.

    Science.gov (United States)

    Bekiroglu, Korkut; Lagoa, Constantino; Murphy, Suzan A; Lanza, Stephanie T

    2017-05-01

    In this paper, a robust control approach is used to address the problem of adaptive behavioral treatment design. Human behavior (e.g., smoking and exercise) and reactions to treatment are complex and depend on many unmeasurable external stimuli, some of which are unknown. Thus, it is crucial to model human behavior over many subject responses. We propose a simple (low order) uncertain affine model subject to uncertainties whose response covers the most probable behavioral responses. The proposed model contains two different types of uncertainties: uncertainty of the dynamics and external perturbations that patients face in their daily life. Once the uncertain model is defined, we demonstrate how least absolute shrinkage and selection operator (lasso) can be used as an identification tool. The lasso algorithm provides a way to directly estimate a model subject to sparse perturbations. With this estimated model, a robust control algorithm is developed, where one relies on the special structure of the uncertainty to develop efficient optimization algorithms. This paper concludes by using the proposed algorithm in a numerical experiment that simulates treatment for the urge to smoke.

  1. Robust predictive control of a gasoline debutanizer column

    Directory of Open Access Journals (Sweden)

    Almeida Neto E.

    2000-01-01

    Full Text Available This paper studies the application of Model Predictive Control to moderately nonlinear processes. The system used in this work is an industrial gasoline debutanizer column. The paper presents two new formulations of MPC: MMPC (Multi-Model Predictive Controller and RSMPC (Robust Stable MPC. The approach is based on the concepts of Linear Matrix Inequalities (LMI, which have been recently introduced in the MPC field. Model uncertainty is considered by assuming that the true process model belongs to a convex set (polytope of possible plants. The controller has guaranteed stability when a Lyapunov type inequality constraint is included in the MPC problem. In the debutanizer column, several nonlinearities are present in the advanced control level when the manipulated inputs are the reflux flow and the reboiler heat duty. In most cases the controlled outputs are the contents of C5+ (pentane and heavier hydrocarbons in the LPG (Liquefied Petroleum Gas and the gasoline vapor pressure (P VR. In this case the QDMC algorithm which is usually applied to the debutanizer column has a poor performance and stability problems reflected in an oscillatory behavior of the process. The new approach considers several process models representing different operating conditions where linear models are identified. The results presented here show that the multimodel controller is capable of controlling the process in the entire operating window while the conventional MPC has a limited operating range.

  2. Robust Control of a Hydraulically Actuated Manipulator Using Sliding Mode Control

    DEFF Research Database (Denmark)

    Hansen, Michael Rygaard; Andersen, Torben Ole; Pedersen, Henrik Clemmensen

    2005-01-01

    This paper presents an approach to robust control called sliding mode control (SMC) applied to the a hydraulic servo system (HSS), consisting of a servo valve controlled symmetrical cylinder. The motivation for applying sliding mode control to hydraulically actuated systems is its robustness...... towards structured (parametric) and unstructured (unmodeled dynamics) uncertainties. A third-order model of the actuated system is used to develop a sliding mode control which is implemented and tested on a simulation model. To avoid measurement of velocity and acceleration a simple first-order model...... is furthermore used to develop a simple sliding mode control (SSMC). The performance of the two controllers are compared and discussed....

  3. Research on cooperative vehicle intersection control scheme without using traffic lights under the connected vehicles environment

    National Research Council Canada - National Science Library

    Zheng, Yi; Jin, Lisheng; Jiang, Yuying; Wang, Fangrong; Guan, Xin; Ji, Shengyuan; Xu, Jun

    2017-01-01

    To improve traffic congestion of urban intersections, this article presents a cooperative vehicle intersection control scheme without using any traffic lights, based on model predictive control theory...

  4. Robust and efficient biometrics based password authentication scheme for telecare medicine information systems using extended chaotic maps.

    Science.gov (United States)

    Lu, Yanrong; Li, Lixiang; Peng, Haipeng; Xie, Dong; Yang, Yixian

    2015-06-01

    The Telecare Medicine Information Systems (TMISs) provide an efficient communicating platform supporting the patients access health-care delivery services via internet or mobile networks. Authentication becomes an essential need when a remote patient logins into the telecare server. Recently, many extended chaotic maps based authentication schemes using smart cards for TMISs have been proposed. Li et al. proposed a secure smart cards based authentication scheme for TMISs using extended chaotic maps based on Lee's and Jiang et al.'s scheme. In this study, we show that Li et al.'s scheme has still some weaknesses such as violation the session key security, vulnerability to user impersonation attack and lack of local verification. To conquer these flaws, we propose a chaotic maps and smart cards based password authentication scheme by applying biometrics technique and hash function operations. Through the informal and formal security analyses, we demonstrate that our scheme is resilient possible known attacks including the attacks found in Li et al.'s scheme. As compared with the previous authentication schemes, the proposed scheme is more secure and efficient and hence more practical for telemedical environments.

  5. Robust isothermal electric control of exchange bias at room temperature

    Science.gov (United States)

    Binek, Christian

    2011-03-01

    Voltage-controlled spintronics is of particular importance to continue progress in information technology through reduced power consumption, enhanced processing speed, integration density, and functionality in comparison with present day CMOS electronics. Almost all existing and prototypical solid-state spintronic devices rely on tailored interface magnetism, enabling spin-selective transmission or scattering of electrons. Controlling magnetism at thin-film interfaces, preferably by purely electrical means, is a key challenge to better spintronics. Currently, most attempts to electrically control magnetism focus on potentially large magnetoelectric effects of multiferroics. We report on our interest in magnetoelectric Cr 2 O3 (chromia). Robust isothermal electric control of exchange bias is achieved at room temperature in perpendicular anisotropic Cr 2 O3 (0001)/CoPd exchange bias heterostructures. This discovery promises significant implications for potential spintronics. From the perspective of basic science, our finding serves as macroscopic evidence for roughness-insensitive and electrically controllable equilibrium boundary magnetization in magnetoelectric antiferromagnets. The latter evolves at chromia (0001) surfaces and interfaces when chromia is in one of its two degenerate antiferromagnetic single domain states selected via magnetoelectric annealing. Theoretical insight into the boundary magnetization and its role in electrically controlled exchange bias is gained from first-principles calculations and general symmetry arguments. Measurements of spin-resolved ultraviolet photoemission, magnetometry at Cr 2 O3 (0001) surfaces, and detailed investigations of the unique exchange bias properties of Cr 2 O3 (0001)/CoPd including its electric controllability provide macroscopically averaged information about the boundary magnetization of chromia. Laterally resolved X-ray PEEM and temperature dependent MFM reveal detailed microscopic information of the chromia

  6. Robust adaptive cruise control of high speed trains.

    Science.gov (United States)

    Faieghi, Mohammadreza; Jalali, Aliakbar; Mashhadi, Seyed Kamal-e-ddin Mousavi

    2014-03-01

    The cruise control problem of high speed trains in the presence of unknown parameters and external disturbances is considered. In particular a Lyapunov-based robust adaptive controller is presented to achieve asymptotic tracking and disturbance rejection. The system under consideration is nonlinear, MIMO and non-minimum phase. To deal with the limitations arising from the unstable zero-dynamics we do an output redefinition such that the zero-dynamics with respect to new outputs becomes stable. Rigorous stability analyses are presented which establish the boundedness of all the internal states and simultaneously asymptotic stability of the tracking error dynamics. The results are presented for two common configurations of high speed trains, i.e. the DD and PPD designs, based on the multi-body model and are verified by several numerical simulations. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Robust Decentralized Adaptive Neural Control for a Class of Nonaffine Nonlinear Large-Scale Systems with Unknown Dead Zones

    Directory of Open Access Journals (Sweden)

    Huanqing Wang

    2014-01-01

    Full Text Available The problem of robust decentralized adaptive neural stabilization control is investigated for a class of nonaffine nonlinear interconnected large-scale systems with unknown dead zones. In the controller design procedure, radical basis function (RBF neural networks are applied to approximate packaged unknown nonlinearities and then an adaptive neural decentralized controller is systematically derived without requiring any information on the boundedness of dead zone parameters (slopes and break points. It is proven that the developed control scheme can ensure that all the signals in the closed-loop system are semiglobally uniformly ultimately bounded in the sense of mean square. Simulation study is provided to further demonstrate the effectiveness of the developed control scheme.

  8. NEURAL CASCADED WITH FUZZY SCHEME FOR CONTROL OF A HYDROELECTRIC POWER PLANT

    OpenAIRE

    A. Selwin Mich Priyadharson; T. Ramesh Kumar; M. S. Saravanan; C. ThilipKumar; D. Dileepan

    2014-01-01

    A novel design for flow and level control in a hydroelectric power plant using Programmable Logic Controller (PLC)-Human Machine Interface (HMI) and neural cascaded with fuzzy scheme is proposed. This project will focus on design and development of flow and level controller for small scale hydro generating units by implementing gate control based on PLC-HMI with the proposed scheme. The existing control schemes have so many difficulties to manage intrinsic time delay, nonlinearity due to unce...

  9. On a switching control scheme for nonlinear systems with ill-defined relative degree

    OpenAIRE

    Chen, W-H; Ballance, D.J.

    2002-01-01

    This paper discusses the applicability of a switching control scheme for a nonlinear system with ill-defined relative degree. The control scheme switches between exact and approximate input-output linearisation control laws. Unlike a linear system under a switching control scheme, the equilibria of a nonlinear system may change with the switching. It is pointed out that this is not sufficient to cause instability. When the region of the approximate linearisation control law is attractive to t...

  10. Robust Active Damping Control of LCL Filtered Grid Connected Converter Based Active Disturbance Rejection Control

    DEFF Research Database (Denmark)

    Abdeldjabar, Benrabah; Xu, Dianguo; Wang, Xiongfei

    2016-01-01

    This paper deals with the problem of LCL filter resonance in grid connected inverter control. The system equations are reformulated to allow the application of the active disturbance rejection control (ADRC). The resonance, assumed unknown, is treated as a disturbance, then estimated and mitigated....... By using this new robust control, a high level of performance is achieved with a minimum complexity in the controller design, and without any adaptive algorithm. It is demonstrated that the true quality of the control system is obtained by the proposed solution. Furthermore, it is shown that this control...... is robust against parameter variations and disturbances....

  11. An Improvement of Robust Biometrics-Based Authentication and Key Agreement Scheme for Multi-Server Environments Using Smart Cards.

    Directory of Open Access Journals (Sweden)

    Jongho Moon

    Full Text Available In multi-server environments, user authentication is a very important issue because it provides the authorization that enables users to access their data and services; furthermore, remote user authentication schemes for multi-server environments have solved the problem that has arisen from user's management of different identities and passwords. For this reason, numerous user authentication schemes that are designed for multi-server environments have been proposed over recent years. In 2015, Lu et al. improved upon Mishra et al.'s scheme, claiming that their remote user authentication scheme is more secure and practical; however, we found that Lu et al.'s scheme is still insecure and incorrect. In this paper, we demonstrate that Lu et al.'s scheme is vulnerable to outsider attack and user impersonation attack, and we propose a new biometrics-based scheme for authentication and key agreement that can be used in multi-server environments; then, we show that our proposed scheme is more secure and supports the required security properties.

  12. An Improvement of Robust and Efficient Biometrics Based Password Authentication Scheme for Telecare Medicine Information Systems Using Extended Chaotic Maps.

    Science.gov (United States)

    Moon, Jongho; Choi, Younsung; Kim, Jiye; Won, Dongho

    2016-03-01

    Recently, numerous extended chaotic map-based password authentication schemes that employ smart card technology were proposed for Telecare Medical Information Systems (TMISs). In 2015, Lu et al. used Li et al.'s scheme as a basis to propose a password authentication scheme for TMISs that is based on biometrics and smart card technology and employs extended chaotic maps. Lu et al. demonstrated that Li et al.'s scheme comprises some weaknesses such as those regarding a violation of the session-key security, a vulnerability to the user impersonation attack, and a lack of local verification. In this paper, however, we show that Lu et al.'s scheme is still insecure with respect to issues such as a violation of the session-key security, and that it is vulnerable to both the outsider attack and the impersonation attack. To overcome these drawbacks, we retain the useful properties of Lu et al.'s scheme to propose a new password authentication scheme that is based on smart card technology and requires the use of chaotic maps. Then, we show that our proposed scheme is more secure and efficient and supports security properties.

  13. An Improvement of Robust Biometrics-Based Authentication and Key Agreement Scheme for Multi-Server Environments Using Smart Cards.

    Science.gov (United States)

    Moon, Jongho; Choi, Younsung; Jung, Jaewook; Won, Dongho

    2015-01-01

    In multi-server environments, user authentication is a very important issue because it provides the authorization that enables users to access their data and services; furthermore, remote user authentication schemes for multi-server environments have solved the problem that has arisen from user's management of different identities and passwords. For this reason, numerous user authentication schemes that are designed for multi-server environments have been proposed over recent years. In 2015, Lu et al. improved upon Mishra et al.'s scheme, claiming that their remote user authentication scheme is more secure and practical; however, we found that Lu et al.'s scheme is still insecure and incorrect. In this paper, we demonstrate that Lu et al.'s scheme is vulnerable to outsider attack and user impersonation attack, and we propose a new biometrics-based scheme for authentication and key agreement that can be used in multi-server environments; then, we show that our proposed scheme is more secure and supports the required security properties.

  14. A Polar Fuzzy Control Scheme for Hybrid Power System Using Vehicle-To-Grid Technique

    Directory of Open Access Journals (Sweden)

    Mohammed Elsayed Lotfy

    2017-07-01

    Full Text Available A novel polar fuzzy (PF control approach for a hybrid power system is proposed in this research. The proposed control scheme remedies the issues of system frequency and the continuity of demand supply caused by renewable sources’ uncertainties. The hybrid power system consists of a wind turbine generator (WTG, solar photovoltaics (PV, a solar thermal power generator (STPG, a diesel engine generator (DEG, an aqua-electrolyzer (AE, an ultra-capacitor (UC, a fuel-cell (FC, and a flywheel (FW. Furthermore, due to the high cost of the battery energy storage system (BESS, a new idea of vehicle-to-grid (V2G control is applied to use the battery of the electric vehicle (EV as equivalent to large-scale energy storage units instead of small batteries to improve the frequency stability of the system. In addition, EV customers’ convenience is taken into account. A minimal-order observer is used to estimate the supply error. Then, the area control error (ACE signal is calculated in terms of the estimated supply error and the frequency deviation. ACE is considered in the frequency domain. Two PF approaches are utilized in the intended system. The mission of each controller is to mitigate one frequency component of ACE. The responsibility for ACE compensation is shared among all parts of the system according to their speed of response. The performance of the proposed control scheme is compared to the conventional fuzzy logic control (FLC. The effectiveness and robustness of the proposed control technique are verified by numerical simulations under various scenarios.

  15. Robust Diffeomorphic Mapping via Geodesically Controlled Active Shapes

    Directory of Open Access Journals (Sweden)

    Daniel J. Tward

    2013-01-01

    Full Text Available This paper presents recent advances in the use of diffeomorphic active shapes which incorporate the conservation laws of large deformation diffeomorphic metric mapping. The equations of evolution satisfying the conservation law are geodesics under the diffeomorphism metric and therefore termed geodesically controlled diffeomorphic active shapes (GDAS. Our principal application in this paper is on robust diffeomorphic mapping methods based on parameterized surface representations of subcortical template structures. Our parametrization of the GDAS evolution is via the initial momentum representation in the tangent space of the template surface. The dimension of this representation is constrained using principal component analysis generated from training samples. In this work, we seek to use template surfaces to generate segmentations of the hippocampus with three data attachment terms: surface matching, landmark matching, and inside-outside modeling from grayscale T1 MR imaging data. This is formulated as an energy minimization problem, where energy describes shape variability and data attachment accuracy, and we derive a variational solution. A gradient descent strategy is employed in the numerical optimization. For the landmark matching case, we demonstrate the robustness of this algorithm as applied to the workflow of a large neuroanatomical study by comparing to an existing diffeomorphic landmark matching algorithm.

  16. Controllability of Boolean networks via input controls under Harvey's update scheme

    Science.gov (United States)

    Luo, Chao; Zhang, Xiaolin; Shao, Rui; Zheng, YuanJie

    2016-02-01

    In this article, the controllability of Boolean networks via input controls under Harvey's update scheme is investigated. First, the model of Boolean control networks under Harvey's stochastic update is proposed, by means of semi-tensor product approach, which is converted into discrete-time linear representation. And, a general formula of control-depending network transition matrix is provided. Second, based on discrete-time dynamics, controllability of the proposed model is analytically discussed by revealing the necessary and sufficient conditions of the reachable sets, respectively, for three kinds of controls, i.e., free Boolean control sequence, input control networks, and close-loop control. Examples are showed to demonstrate the effectiveness and feasibility of the proposed scheme.

  17. Effect of intermittent feedback control on robustness of human-like postural control system

    Science.gov (United States)

    Tanabe, Hiroko; Fujii, Keisuke; Suzuki, Yasuyuki; Kouzaki, Motoki

    2016-03-01

    Humans have to acquire postural robustness to maintain stability against internal and external perturbations. Human standing has been recently modelled using an intermittent feedback control. However, the causality inside of the closed-loop postural control system associated with the neural control strategy is still unknown. Here, we examined the effect of intermittent feedback control on postural robustness and of changes in active/passive components on joint coordinative structure. We implemented computer simulation of a quadruple inverted pendulum that is mechanically close to human tiptoe standing. We simulated three pairs of joint viscoelasticity and three choices of neural control strategies for each joint: intermittent, continuous, or passive control. We examined postural robustness for each parameter set by analysing the region of active feedback gain. We found intermittent control at the hip joint was necessary for model stabilisation and model parameters affected the robustness of the pendulum. Joint sways of the pendulum model were partially smaller than or similar to those of experimental data. In conclusion, intermittent feedback control was necessary for the stabilisation of the quadruple inverted pendulum. Also, postural robustness of human-like multi-link standing would be achieved by both passive joint viscoelasticity and neural joint control strategies.

  18. Robust attitude coordinated control for spacecraft formation with communication delays

    Directory of Open Access Journals (Sweden)

    Jian ZHANG

    2017-06-01

    Full Text Available In this paper, attitude coordinated tracking control algorithms for multiple spacecraft formation are investigated with consideration of parametric uncertainties, external disturbances, communication delays and actuator saturation. Initially, a sliding mode delay-dependent attitude coordinated controller is proposed under bounded external disturbances. However, neither inertia uncertainty nor actuator constraint has been taken into account. Then, a robust saturated delay-dependent attitude coordinated control law is further derived, where uncertainties and external disturbances are handled by Chebyshev neural networks (CNN. In addition, command filter technique is introduced to facilitate the backstepping design procedure, through which actuator saturation problem is solved. Thus the spacecraft in the formation are able to track the reference attitude trajectory even in the presence of time-varying communication delays. Rigorous analysis is presented by using Lyapunov-Krasovskii approach to demonstrate the stability of the closed-loop system under both control algorithms. Finally, the numerical examples are carried out to illustrate the efficiency of the theoretical results.

  19. Sensor scheme design for active structural acoustic control

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    Efficient sensing schemes for the active reduction of sound radiation from plates are presented based on error signals derived from spatially weighted plate velocity or near-field pressure. The schemes result in near-optimal reductions as compared to weighting procedures derived from eigenvector or

  20. Lyapunov function-based control laws for revolute robot arms - Tracking control, robustness, and adaptive control

    Science.gov (United States)

    Wen, John T.; Kreutz-Delgado, Kenneth; Bayard, David S.

    1992-01-01

    A new class of joint level control laws for all-revolute robot arms is introduced. The analysis is similar to a recently proposed energy-like Liapunov function approach, except that the closed-loop potential function is shaped in accordance with the underlying joint space topology. This approach gives way to a much simpler analysis and leads to a new class of control designs which guarantee both global asymptotic stability and local exponential stability. When Coulomb and viscous friction and parameter uncertainty are present as model perturbations, a sliding mode-like modification of the control law results in a robustness-enhancing outer loop. Adaptive control is formulated within the same framework. A linear-in-the-parameters formulation is adopted and globally asymptotically stable adaptive control laws are derived by simply replacing unknown model parameters by their estimates (i.e., certainty equivalence adaptation).

  1. 31 CFR 592.301 - Controlled through the Kimberley Process Certification Scheme.

    Science.gov (United States)

    2010-07-01

    ... Process Certification Scheme. 592.301 Section 592.301 Money and Finance: Treasury Regulations Relating to... Certification Scheme. (a) Except as otherwise provided in paragraph (b) of this section, the term controlled through the Kimberley Process Certification Scheme refers to the following requirements that apply, as...

  2. Robust fractional order sliding mode control of doubly-fed induction generator (DFIG)-based wind turbines.

    Science.gov (United States)

    Ebrahimkhani, Sadegh

    2016-07-01

    Wind power plants have nonlinear dynamics and contain many uncertainties such as unknown nonlinear disturbances and parameter uncertainties. Thus, it is a difficult task to design a robust reliable controller for this system. This paper proposes a novel robust fractional-order sliding mode (FOSM) controller for maximum power point tracking (MPPT) control of doubly fed induction generator (DFIG)-based wind energy conversion system. In order to enhance the robustness of the control system, uncertainties and disturbances are estimated using a fractional order uncertainty estimator. In the proposed method a continuous control strategy is developed to achieve the chattering free fractional order sliding-mode control, and also no knowledge of the uncertainties and disturbances or their bound is assumed. The boundedness and convergence properties of the closed-loop signals are proven using Lyapunov׳s stability theory. Simulation results in the presence of various uncertainties were carried out to evaluate the effectiveness and robustness of the proposed control scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  3. Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    McEntee, Jarlath [Ocean Renewable Power Company, Portland, ME (United States); Polagye, Brian [Ocean Renewable Power Company, Portland, ME (United States); Fabien, Brian [Ocean Renewable Power Company, Portland, ME (United States); Thomson, Jim [Ocean Renewable Power Company, Portland, ME (United States); Kilcher, Levi [Ocean Renewable Power Company, Portland, ME (United States); Marnagh, Cian [Ocean Renewable Power Company, Portland, ME (United States); Donegan, James [Ocean Renewable Power Company, Portland, ME (United States)

    2016-03-31

    The Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices (Project) investigated, analyzed and modeled advanced turbine control schemes with the objective of increasing the energy harvested by hydrokinetic turbines in turbulent flow. Ocean Renewable Power Company (ORPC) implemented and validated a feedforward controller to increase power capture; and applied and tested the controls on ORPC’s RivGen® Power Systems in Igiugig, Alaska. Assessments of performance improvements were made for the RivGen® in the Igiugig environment and for ORPC’s TidGen® Power System in a reference tidal environment. Annualized Energy Production (AEP) and Levelized Cost of Energy (LCOE) improvements associated with implementation of the recommended control methodology were made for the TidGen® Power System in the DOE reference tidal environment. System Performance Advancement (SPA) goals were selected for the project. SPA targets were to improve Power to Weight Ratio (PWR) and system Availability, with the intention of reducing Levelized Cost of Electricity (LCOE). This project focused primarily reducing in PWR. Reductions in PWR of 25.5% were achieved. Reductions of 20.3% in LCOE were achieved. This project evaluated four types of controllers which were tested in simulation, emulation, a laboratory flume, and the field. The adaptive Kω2 controller performs similarly to the non-adaptive version of the same controller and may be useful in tidal channels where the mean velocity is continually evolving. Trends in simulation were largely verified through experiments, which also provided the opportunity to test assumptions about turbine responsiveness and control resilience to varying scales of turbulence. Laboratory experiments provided an essential stepping stone between simulation and implementation on a field-scale turbine. Experiments also demonstrated that using “energy loss” as a metric to differentiate between well-designed controllers operating at

  4. Fast and robust quantum control based on Pauli blocking

    Science.gov (United States)

    Dowdall, Tom; Benseny, Albert; Busch, Thomas; Ruschhaupt, Andreas

    2017-10-01

    Coherent quantum control over many-particle quantum systems requires high-fidelity dynamics. One way of achieving this is to use adiabatic schemes where the system follows an instantaneous eigenstate of the Hamiltonian over time scales that do not allow transitions to other states. This, however, makes control dynamics very slow. Here we introduce another concept that takes advantage of preventing unwanted transitions in fermionic systems by using Pauli blocking: excitations from a protected ground state to higher-lying states are avoided by adding a layer of buffer fermions, such that the protected fermions cannot make a transition to higher-lying excited states because these are already occupied. This allows us to speed up adiabatic evolutions of the system. We do a thorough investigation of the technique, and demonstrate its power by applying it to high-fidelity transport, trap expansion, and splitting in ultracold-atom systems in anharmonic traps. Close analysis of these processes also leads to insights into the structure of the orthogonality catastrophe phenomenon.

  5. Transient Stability Enhancement of Multimachine Power System Using Robust and Novel Controller Based CSC-STATCOM

    Directory of Open Access Journals (Sweden)

    Sandeep Gupta

    2015-01-01

    Full Text Available A current source converter (CSC based static synchronous compensator (STATCOM is a shunt flexible AC transmission system (FACTS device, which has a vital role as a stability support for small and large transient instability in an interconnected power network. This paper investigates the impact of a novel and robust pole-shifting controller for CSC-STATCOM to improve the transient stability of the multimachine power system. The proposed algorithm utilizes CSC based STATCOM to supply reactive power to the test system to maintain the transient stability in the event of severe contingency. Firstly, modeling and pole-shifting controller design for CSC based STATCOM are stated. After that, we show the impact of the proposed method in the multimachine power system with different disturbances. Here, applicability of the proposed scheme is demonstrated through simulation in MATLAB and the simulation results show an improvement in the transient stability of multimachine power system with CSC-STATCOM. Also clearly shown, the robustness and effectiveness of CSC-STATCOM are better rather than other shunt FACTS devices (SVC and VSC-STATCOM by comparing the results in this paper.

  6. Fractional order differentiation and robust control design crone, h-infinity and motion control

    CERN Document Server

    Sabatier, Jocelyn; Melchior, Pierre; Oustaloup, Alain

    2015-01-01

    This monograph collates the past decade’s work on fractional models and fractional systems in the fields of analysis, robust control and path tracking. Themes such as PID control, robust path tracking design and motion control methodologies involving fractional differentiation are amongst those explored. It juxtaposes recent theoretical results at the forefront in the field, and applications that can be used as exercises that will help the reader to assimilate the proposed methodologies. The first part of the book deals with fractional derivative and fractional model definitions, as well as recent results for stability analysis, fractional model physical interpretation, controllability, and H-infinity norm computation. It also presents a critical point of view on model pseudo-state and “real state”, tackling the problem of fractional model initialization. Readers will find coverage of PID, Fractional PID and robust control in the second part of the book, which rounds off with an extension of H-infinity ...

  7. From bounded-noise data to robust PI-controller design

    NARCIS (Netherlands)

    Steinbuch, Luc; Keesman, K.J.

    2015-01-01

    An approach is presented to design a robust PI-controller from bounded noise measurement data of a first order process with and without time delay. This controller guarantees a known robust performance. It is shown that in the case without time delay, the conservatism of the robust approach can

  8. Application of a robust QFT linear control method to the course changing manoeuvring of a ship

    OpenAIRE

    Rueda Rodríguez, Teresa M.; Velasco González, Francisco Jesús; Moyano Pérez, Emiliano; López García, Eloy; Cruz García, Jesús Manuel de la

    2005-01-01

    This paper describes in detail the design methodology of a robust QFT (Quantitative Feedback Theory) controller for the control of the course changing of a ship. A linear model is used with uncertainty in the parameters. The system is designed to fulfil the specifications of robust stability and robust tracking of a reference system.

  9. Controllable and Anonymous Authentication Scheme for Space Networks

    Directory of Open Access Journals (Sweden)

    Hu Zhi-Yan

    2017-01-01

    Full Text Available This paper analyzed the existing anonymous authentication schemes which have the weakness of high calculation and communication cost and weak security. So we designed a secure and efficient anonymous authentication scheme to meet the need of the space network, which has the characteristic of resource limited, high exposure and intermittent connectivity. At first we proposed a signature algorithm based on certificateless public key cryptosystem and one-off public key, and then presented an anonymous authentication scheme according to the proposed signature algorithm, it needs two message interaction to complete the mutual authentication and key agreement. When the user has the illegal behavior, the service provider can reveal the illegal user’s real identity through cooperation with the trusted center. Compared with the similar literature, the proposed scheme achieves high security with low computation and communication cost. (Abstract

  10. Robust Control of Aeronautical Electrical Generators for Energy Management Applications

    Directory of Open Access Journals (Sweden)

    Giacomo Canciello

    2017-01-01

    Full Text Available A new strategy for the control of aeronautical electrical generators via sliding manifold selection is proposed, with an associated innovative intelligent energy management strategy used for efficient power transfer between two sources providing energy to aeronautical loads, having different functionalities and priorities. Electric generators used for aeronautical application involve several machines, including a main generator and an exciter. Standard regulators (PI or PID-like are normally used for the rectification of the generator voltage to be used to supply a high-voltage DC bus. The regulation is obtained by acting on a DC/DC converter that imposes the field voltage of the exciter. In this paper, the field voltage is fed to the generator windings by using a second-order sliding mode controller, resulting into a stable, robust (against disturbances action and a fast convergence to the desired reference. By using this strategy, an energy management strategy is proposed that dynamically changes the voltage set point, in order to intelligently transfer power between two voltage busses. Detailed simulation results are provided in order to show the effectiveness of the proposed energy management strategy in different scenarios.

  11. S-variable approach to LMI-based robust control

    CERN Document Server

    Ebihara, Yoshio; Arzelier, Denis

    2015-01-01

    This book shows how the use of S-variables (SVs) in enhancing the range of problems that can be addressed with the already-versatile linear matrix inequality (LMI) approach to control can, in many cases, be put on a more unified, methodical footing. Beginning with the fundamentals of the SV approach, the text shows how the basic idea can be used for each problem (and when it should not be employed at all). The specific adaptations of the method necessitated by each problem are also detailed. The problems dealt with in the book have the common traits that: analytic closed-form solutions are not available; and LMIs can be applied to produce numerical solutions with a certain amount of conservatism. Typical examples are robustness analysis of linear systems affected by parametric uncertainties and the synthesis of a linear controller satisfying multiple, often  conflicting, design specifications. For problems in which LMI methods produce conservative results, the SV approach is shown to achieve greater accuracy...

  12. A control scheme for filament stretching rheometers with application to polymer melts

    DEFF Research Database (Denmark)

    Román Marín, José Manuel; Huusom, Jakob Kjøbsted; Javier Alvarez, Nicolas

    2013-01-01

    We propose a new control scheme to maintain a constant strain rate of the mid-filament diameter in a filament stretching rheometer for polymer melts. The scheme is cast as a velocity algorithm and consists of a feed-back and a feed-forward contribution. The performance of the controller is demons......We propose a new control scheme to maintain a constant strain rate of the mid-filament diameter in a filament stretching rheometer for polymer melts. The scheme is cast as a velocity algorithm and consists of a feed-back and a feed-forward contribution. The performance of the controller...

  13. Modelling and robust control of an unmanned coaxial rotor helicopter with unstructured uncertainties

    Directory of Open Access Journals (Sweden)

    Zhi-Yan Dong

    2017-01-01

    Full Text Available A complete methodology for an unmanned coaxial rotor helicopter with unstructured uncertainties was proposed to achieve high-accuracy tracking performance from modelling to robust control. An integrative approach was introduced to systematically construct a whole dynamic model. The key parameters were selected carefully after iteratively being checked by empirical coefficients to decrease the budget and risk of programme. Moreover, a new control scheme is proposed to simultaneously incorporate six inputs to control six states based on the investment of singularity value responses and the general rule of relative gain array. Coprime factor uncertainty model is considered to represent a class of unstructured uncertainties, such as unmolded actuator dynamics and unpredicted interferences between two rotors. Furthermore, the H ∞ loop-shaping control was proposed to apply the control design of the coaxial rotor helicopter to manage complicated uncertainties and multivariable coupling. Finally, simulation results show the effectiveness of the proposed controller design in the step response of the closed loop. The stable closed-loop plant is achieved and the tolerant size of unstructured uncertainty is up to 36.09%. Good step responses and satisfied decoupling were also investigated in detail.

  14. Dual-loop self-optimizing robust control of wind power generation with Doubly-Fed Induction Generator.

    Science.gov (United States)

    Chen, Quan; Li, Yaoyu; Seem, John E

    2015-09-01

    This paper presents a self-optimizing robust control scheme that can maximize the power generation for a variable speed wind turbine with Doubly-Fed Induction Generator (DFIG) operated in Region 2. A dual-loop control structure is proposed to synergize the conversion from aerodynamic power to rotor power and the conversion from rotor power to the electrical power. The outer loop is an Extremum Seeking Control (ESC) based generator torque regulation via the electric power feedback. The ESC can search for the optimal generator torque constant to maximize the rotor power without wind measurement or accurate knowledge of power map. The inner loop is a vector-control based scheme that can both regulate the generator torque requested by the ESC and also maximize the conversion from the rotor power to grid power. An ℋ(∞) controller is synthesized for maximizing, with performance specifications defined based upon the spectrum of the rotor power obtained by the ESC. Also, the controller is designed to be robust against the variations of some generator parameters. The proposed control strategy is validated via simulation study based on the synergy of several software packages including the TurbSim and FAST developed by NREL, Simulink and SimPowerSystems. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Intelligent robust control law for induction motors based on field-oriented control theory

    Energy Technology Data Exchange (ETDEWEB)

    Barambones, O.; Alcorta, P.; Sevillano, G.; Garrido, A.; Garrido, I. [Univ. del Pais Vasco, Bilbao (Spain). Dpto. Ingenieri a de Sistemas y Automatica

    2009-07-01

    A sensorless adaptive control law was developed to improve the trajectory tracking performance of induction motors. The law used an integral sliding mode algorithm to avoid the necessity of calculating an upper bound for system uncertainties. The vector control theory was used to develop the induction motor drives. The sliding mode control law incorporated an adaptive switching gain and included a method of estimating rotor speeds. Rotor speed estimation errors were presented as a first order simple function based on the difference between real stator currents and estimated stator currents. The Lyapunov stability theory was used to analyze the controller under different load disturbances and parameter uncertainties. Results of the study showed that the control signal of the scheme was smaller than signals obtained using traditional variable structure control schemes. It was concluded that speed tracking objectives can be obtained under various parameter and torque uncertainties. 9 refs., 7 figs.

  16. Hierarchical Control Scheme for Voltage Harmonics Compensation in an Islanded Droop-Controlled Microgrid

    DEFF Research Database (Denmark)

    Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza

    2011-01-01

    controllers, and virtual impedance loop. A novel virtual impedance structure is proposed to achieve proper sharing of non-fundamental power among the microgrid DGs. The secondary level is designed to manage compensation of voltage harmonics at the microgrid load bus (LB) to which the sensitive loads may......In this paper, a microgrid hierarchical control scheme is proposed which includes primary and secondary control levels. The primary level comprises distributed generators (DGs) local controllers. The local controller mainly consists of active and reactive power controllers, voltage and current...

  17. Stabilization and analytical tuning rule of double-loop control scheme for unstable dead-time process

    Science.gov (United States)

    Ugon, B.; Nandong, J.; Zang, Z.

    2017-06-01

    The presence of unstable dead-time systems in process plants often leads to a daunting challenge in the design of standard PID controllers, which are not only intended to provide close-loop stability but also to give good performance-robustness overall. In this paper, we conduct stability analysis on a double-loop control scheme based on the Routh-Hurwitz stability criteria. We propose to use this unstable double-loop control scheme which employs two P/PID controllers to control first-order or second-order unstable dead-time processes typically found in process industries. Based on the Routh-Hurwitz stability necessary and sufficient criteria, we establish several stability regions which enclose within them the P/PID parameter values that guarantee close-loop stability of the double-loop control scheme. A systematic tuning rule is developed for the purpose of obtaining the optimal P/PID parameter values within the established regions. The effectiveness of the proposed tuning rule is demonstrated using several numerical examples and the result are compared with some well-established tuning methods reported in the literature.

  18. Controlling a pH Process Using Feedback & Double Controller Scheme

    Directory of Open Access Journals (Sweden)

    S. Shobana

    2009-09-01

    Full Text Available Control of pH, particularly, in industrial application, is difficult and challenging due to its time-varying and nonlinear nature of the chemical or biological process. This non-linearity does however suggest that pH control would be a suitable application area for a model based double-control system, whose ability to handle non-linearity is well known. The mathematical model of pH for a weak acid-strong base is used to design IMC based PID double-controller scheme which provides outstanding setpoint tracking and disturbances rejection simultaneously to control pH processes.

  19. Synthesis of fixed-architecture, robust H 2 and H ∞ controllers

    Directory of Open Access Journals (Sweden)

    Collins Jr. Emmanuel G.

    2000-01-01

    Full Text Available This paper discusses and compares the synthesis of fixed-architecture controllers that guarantee either robust H 2 or H ∞ performance. The synthesis is accomplished by solving a Riccati equation feasibility problem resulting from mixed structured singular value theory with Popov multipliers. Whereas the algorithm for robust H 2 performance had been previously implemented, a major contribution described in this paper is the implementation of the much more complex algorithm for robust H ∞ performance. Both robust H 2 and H ∞ , controllers are designed for a benchmark problem and a comparison is made between the resulting controllers and control algorithms. It is found that the numerical algorithm for robust H ∞ performance is much more computationally intensive than that for robust H 2 performance. Both controllers are found to have smaller bandwidth, lower control authority and to be less conservative than controllers obtained using complex structured singular value synthesis

  20. Robust Distributed Power Control in Cognitive Radio Networks

    CERN Document Server

    fard, Saeideh Parsaei

    2011-01-01

    We propose a robust distributed uplink power allocation algorithm for underlay cognitive radio networks (CRNs) with a view to maximizing the total utility of secondary users (SUs) when channel gains from SUs to primary base stations, and interference caused by primary users (PUs) to the SUs' base station are uncertain. In doing so, we utilize the worst-case robust optimization to keep the interference caused by SUs to each primary base station below a given threshold, and satisfy the SUs' quality of service for all realizations of uncertainty. We model each uncertain parameter by a bounded distance between its estimated and exact values, and formulate the robust power allocation problem via protection values for constraints. We demonstrate that the convexity of our problem is preserved, and in some cases converts into a geometric programming problem, which we solve via a distributed algorithm by using Lagrange dual decomposition. To reduce the cost of robustness, defined as the reduction in the total utility ...

  1. Robust Frequency and Voltage Stability Control Strategy for Standalone AC/DC Hybrid Microgrid

    Directory of Open Access Journals (Sweden)

    Furqan Asghar

    2017-05-01

    Full Text Available The microgrid (MG concept is attracting considerable attention as a solution to energy deficiencies, especially in remote areas, but the intermittent nature of renewable sources and varying loads cause many control problems and thereby affect the quality of power within a microgrid operating in standalone mode. This might cause large frequency and voltage deviations in the system due to unpredictable output power fluctuations. Furthermore, without any main grid support, it is more complex to control and manage the system. In past, droop control and various other coordination control strategies have been presented to stabilize the microgrid frequency and voltages, but in order to utilize the available resources up to their maximum capacity in a positive way, new and robust control mechanisms are required. In this paper, a standalone microgrid is presented, which integrates renewable energy-based distributed generations and local loads. A fuzzy logic-based intelligent control technique is proposed to maintain the frequency and DC (direct current-link voltage stability for sudden changes in load or generation power. Also from a frequency control perspective, a battery energy storage system (BESS is suggested as a replacement for a synchronous generator to stabilize the nominal system frequency as a synchronous generator is unable to operate at its maximum efficiency while being controlled for stabilization purposes. Likewise, a super capacitor (SC and BESS is used to stabilize DC bus voltages even though maximum possible energy is being extracted from renewable generated sources using maximum power point tracking. This newly proposed control method proves to be effective by reducing transient time, minimizing the frequency deviations, maintaining voltages even though maximum power point tracking is working and preventing generators from exceeding their power ratings during disturbances. However, due to the BESS limited capacity, load switching

  2. Performance evaluation of time-delay control schemes for uninterruptible power supplies

    DEFF Research Database (Denmark)

    Loh, P.C; Tang, Y.; Blaabjerg, Frede

    2008-01-01

    transitions. Even more favorable is that the above-described performance features are attained under all load-operating conditions and at the same level of implementation easiness as for the traditional double-loop control scheme. Lastly, for verifying the practicality of the control schemes, an experimental...

  3. A simple output voltage control scheme for single phase wavelet ...

    African Journals Online (AJOL)

    DR OKE

    Wavelet based techniques have been extensively used in various power engineering applications. Recently, wavelet has also been proposed to generate switching signal for single-phase pulse-width-modulated (PWM) dc-ac inverter. The main advantage of the wavelet modulated (WM) scheme is that a single synthesis ...

  4. Robustness and Actuator Bandwidth of MRP-Based Sliding Mode Control for Spacecraft Attitude Control Problems

    Science.gov (United States)

    Keum, Jung-Hoon; Ra, Sung-Woong

    2009-12-01

    Nonlinear sliding surface design in variable structure systems for spacecraft attitude control problems is studied. A robustness analysis is performed for regular form of system, and calculation of actuator bandwidth is presented by reviewing sliding surface dynamics. To achieve non-singular attitude description and minimal parameterization, spacecraft attitude control problems are considered based on modified Rodrigues parameters (MRP). It is shown that the derived controller ensures the sliding motion in pre-determined region irrespective of unmodeled effects and disturbances.

  5. Semiactive balancing control scheme in a rotor - bearing system supported on Mr. Dampers: design and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Silva Navarro, Gerardo; Cabrera Amado, Alvaro [Cinvestav, IPN, Mexico, D.F. (Mexico)

    2007-11-15

    This paper deals with the problem of semiactive balancing control of a rotor-bearing system, where one journal bearings is supported on two radial Magneto-Rheological (MR) dampers. The mathematical model of the rotor-bearing system results from an orthotropic Jeffcott-like model and the dynamics associated to the MR dampers, whose rheological properties depend on the current inputs. For control purposes we use the Choi-Lee-Park polynomial for the MR dampers, which is quite consistent with the tpical nonlinear and complex hysteresis behavior and also simplifies the physical implementation on an experimental setup. The semiactive control scheme for the unbalance reponse of the rotor-bearing system is synthesized using sliding-mode control techniques. Some numerical and experimental results are included to illustrate the dynamic performance and robustness of the overall system. [Spanish] En este trabajo se abora el problema de control semiactivo del desbalance en un sistema rotor-chumacera, donde una de las chumaceras convencionales se monta sobre una suspension con dos amortiguadores Magneto-Reologicos (MR) radiales. El modelo matematico del sistema rotorchumacera se obtiene de un modelo tipo Jefcott ortotropico y la dinamica de los amortiguadores MR, cuyas propiedades reologicas dependen de las corrientes electricas de alimentacion. Para propositos de control se emplea el modelo polinomial de Choi-Lee-Park para los dos amortiguadores MR, el cual es consistente con el tipico comportamiento no-lineal y de histeresis, permitiendo simplificar su implementacion fisica en una plataforma experimental. El esquema de control semiactivo de la respuesta al desbalance, en el sistema rotor-chumacera, se basa en las tecnicas de control por modos deslizantes. Se presentan algunos resultados de simulacion numerica y experimentos que utilizan el funcionamiento y robustez del sistema completo.

  6. Controlling a pH Process Using Feedback & Double Controller Scheme

    OpenAIRE

    S.Shobana; Srinivasan, A.; Rames C.Panda

    2009-01-01

    Control of pH, particularly, in industrial application, is difficult and challenging due to its time-varying and nonlinear nature of the chemical or biological process. This non-linearity does however suggest that pH control would be a suitable application area for a model based double-control system, whose ability to handle non-linearity is well known. The mathematical model of pH for a weak acid-strong base is used to design IMC based PID double-controller scheme which provides outstanding ...

  7. Multivariable Robust Control of a Simulated Hybrid Solid Oxide Fuel Cell Gas Turbine Plant

    Energy Technology Data Exchange (ETDEWEB)

    Tsai A, Banta L, Tucker D

    2010-08-01

    This work presents a systematic approach to the multivariable robust control of a hybrid fuel cell gas turbine plant. The hybrid configuration under investigation built by the National Energy Technology Laboratory comprises a physical simulation of a 300kW fuel cell coupled to a 120kW auxiliary power unit single spool gas turbine. The public facility provides for the testing and simulation of different fuel cell models that in turn help identify the key difficulties encountered in the transient operation of such systems. An empirical model of the built facility comprising a simulated fuel cell cathode volume and balance of plant components is derived via frequency response data. Through the modulation of various airflow bypass valves within the hybrid configuration, Bode plots are used to derive key input/output interactions in transfer function format. A multivariate system is then built from individual transfer functions, creating a matrix that serves as the nominal plant in an H{sub {infinity}} robust control algorithm. The controller’s main objective is to track and maintain hybrid operational constraints in the fuel cell’s cathode airflow, and the turbo machinery states of temperature and speed, under transient disturbances. This algorithm is then tested on a Simulink/MatLab platform for various perturbations of load and fuel cell heat effluence. As a complementary tool to the aforementioned empirical plant, a nonlinear analytical model faithful to the existing process and instrumentation arrangement is evaluated and designed in the Simulink environment. This parallel task intends to serve as a building block to scalable hybrid configurations that might require a more detailed nonlinear representation for a wide variety of controller schemes and hardware implementations.

  8. Robust Multivariable Flutter Suppression for the Benchmark Active Control Technology (BACT) Wind-Tunnel Model

    Science.gov (United States)

    Waszak, Martin R.

    1997-01-01

    The Benchmark Active Controls Technology (BACT) project is part of NASA Langley Research Center s Benchmark Models Program for studying transonic aeroelastic phenomena. In January of 1996 the BACT wind-tunnel model was used to successfully demonstrate the application of robust multivariable control design methods (H and -synthesis) to flutter suppression. This paper addresses the design and experimental evaluation of robust multivariable flutter suppression control laws with particular attention paid to the degree to which stability and performance robustness was achieved.

  9. A comparison of a novel robust decentralised control strategy and MPC for industrial high purity, high recovery, multicomponent distillation.

    Science.gov (United States)

    Udugama, Isuru A; Wolfenstetter, Florian; Kirkpatrick, Robert; Yu, Wei; Young, Brent R

    2017-07-01

    In this work we have developed a novel, robust practical control structure to regulate an industrial methanol distillation column. This proposed control scheme is based on a override control framework and can manage a non-key trace ethanol product impurity specification while maintaining high product recovery. For comparison purposes, a MPC with a discrete process model (based on step tests) was also developed and tested. The results from process disturbance testing shows that, both the MPC and the proposed controller were capable of maintaining both the trace level ethanol specification in the distillate (XD) and high product recovery (β). Closer analysis revealed that the MPC controller has a tighter XD control, while the proposed controller was tighter in β control. The tight XD control allowed the MPC to operate at a higher XD set point (closer to the 10ppm AA grade methanol standard), allowing for savings in energy usage. Despite the energy savings of the MPC, the proposed control scheme has lower installation and running costs. An economic analysis revealed a multitude of other external economic and plant design factors, that should be considered when making a decision between the two controllers. In general, we found relatively high energy costs favour MPC. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Universal block diagram based modeling and simulation schemes for fractional-order control systems.

    Science.gov (United States)

    Bai, Lu; Xue, Dingyü

    2017-05-08

    Universal block diagram based schemes are proposed for modeling and simulating the fractional-order control systems in this paper. A fractional operator block in Simulink is designed to evaluate the fractional-order derivative and integral. Based on the block, the fractional-order control systems with zero initial conditions can be modeled conveniently. For modeling the system with nonzero initial conditions, the auxiliary signal is constructed in the compensation scheme. Since the compensation scheme is very complicated, therefore the integrator chain scheme is further proposed to simplify the modeling procedures. The accuracy and effectiveness of the schemes are assessed in the examples, the computation results testify the block diagram scheme is efficient for all Caputo fractional-order ordinary differential equations (FODEs) of any complexity, including the implicit Caputo FODEs. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  11. An Enhanced Control Scheme for Uninterruptible Power Supply

    DEFF Research Database (Denmark)

    Lu, Jinghang; Savaghebi, Mehdi; Wei, Baoze

    2017-01-01

    and robustness. Moreover, virtual resistance based regulation strategies are proposed for solving the active power sharing imbalance caused by the active power feeding and harmonic power sharing imbalanced caused by the line resistance mismatching. In addition, an anti-windup based consensus distributed...... prototypes....

  12. Robust control of CPG-based 3D neuromusculoskeletal walking model.

    Science.gov (United States)

    Kim, Youngwoo; Tagawa, Yusuke; Obinata, Goro; Hase, Kazunori

    2011-10-01

    This paper proposes a method for enhancing the robustness of the central pattern generator (CPG)-based three-dimensional (3D) neuromusculoskeletal walking controller. The CPG has been successfully applied to walking controllers and controllers for walking robots. However, the robustness of walking motion with the CPG-based controller is not sufficient, especially when subjected to external forces or environmental variations. To achieve a realistic and stable walking motion of the controller, we propose the use of an attracting controller in parallel with the CPG-based controller. The robustness of the proposed controller is confirmed through simulation results.

  13. H∞ Robust Current Control for DFIG Based Wind Turbine subject to Grid Voltage Distortions

    DEFF Research Database (Denmark)

    Wang, Yun; Wu, Qiuwei; Gong, Wenming

    2016-01-01

    This paper proposes an H∞ robust current controller for doubly fed induction generator (DFIG) based wind turbines (WTs) subject to grid voltage distortions. The controller is to mitigate the impact of the grid voltage distortions on rotor currents with DFIG parameter perturbation. The grid voltage...... are designed to efficiently track the unbalanced current components and the 5th and 7th background harmonics. The robust stability (RS) and robust performance (RP) of the proposed controller are verified by the structured singular value µ. The performance of the H∞ robust current controller was demonstrated...

  14. Observation Quality Control with a Robust Ensemble Kalman Filter

    KAUST Repository

    Roh, Soojin

    2013-12-01

    Current ensemble-based Kalman filter (EnKF) algorithms are not robust to gross observation errors caused by technical or human errors during the data collection process. In this paper, the authors consider two types of gross observational errors, additive statistical outliers and innovation outliers, and introduce a method to make EnKF robust to gross observation errors. Using both a one-dimensional linear system of dynamics and a 40-variable Lorenz model, the performance of the proposed robust ensemble Kalman filter (REnKF) was tested and it was found that the new approach greatly improves the performance of the filter in the presence of gross observation errors and leads to only a modest loss of accuracy with clean, outlier-free, observations.

  15. A Quantum Proxy Weak Blind Signature Scheme Based on Controlled Quantum Teleportation

    Science.gov (United States)

    Cao, Hai-Jing; Yu, Yao-Feng; Song, Qin; Gao, Lan-Xiang

    2015-04-01

    Proxy blind signature is applied to the electronic paying system, electronic voting system, mobile agent system, security of internet, etc. A quantum proxy weak blind signature scheme is proposed in this paper. It is based on controlled quantum teleportation. Five-qubit entangled state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement message blinding, so it could guarantee not only the unconditional security of the scheme but also the anonymity of the messages owner.

  16. Robust LMI-Based Control of Wind Turbines with Parametric Uncertainties

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Esbensen, Thomas; Niss, Michael Odgaard Kuch

    2009-01-01

    This paper considers the design of robust LMI-based controllers for a wind turbine along its entire nominal operating trajectory. The proposed robust controller design takes into account parametric uncertainties in the model using a structured uncertainty description, which makes the controllers...

  17. An Interval Approach for Robust Control of a Large PHWR with PID Controllers

    Science.gov (United States)

    Banerjee, Shohan; Halder, Kaushik; Dasgupta, Soumya; Mukhopadhyay, Siddhartha; Ghosh, Koushik; Gupta, Amitava

    2015-02-01

    A nuclear reactor exhibits changing behavior with variation in reactor power. Further, uncertainties in the measurement of the actual power produced by the reactor, the heat transfer from the fuel to the coolant and the reactivity change due to the change in the fuel and coolant temperatures and condition of the core, make it necessary to adopt a robust control approach for design of control systems for such plants. In this paper a 540 MWe Indian PHWR consisting of 14 zones has been modeled using inexact models incorporating bounded parametric variations in power, heat transfer from the fuel to the coolant and temperature coefficients of reactivity of fuel and coolant. These inexact models are then used to obtain a robust and optimal PID controller gains for controlling the reactor power with specified time response under parametric variations, using an interval approach. The methodology is established with credible MATLAB simulations.

  18. Robust control of integrated motor-transmission powertrain system over controller area network for automotive applications

    Science.gov (United States)

    Zhu, Xiaoyuan; Zhang, Hui; Cao, Dongpu; Fang, Zongde

    2015-06-01

    Integrated motor-transmission (IMT) powertrain system with directly coupled motor and gearbox is a good choice for electric commercial vehicles (e.g., pure electric buses) due to its potential in motor size reduction and energy efficiency improvement. However, the controller design for powertrain oscillation damping becomes challenging due to the elimination of damping components. On the other hand, as controller area network (CAN) is commonly adopted in modern vehicle system, the network-induced time-varying delays that caused by bandwidth limitation will further lead to powertrain vibration or even destabilize the powertrain control system. Therefore, in this paper, a robust energy-to-peak controller is proposed for the IMT powertrain system to address the oscillation damping problem and also attenuate the external disturbance. The control law adopted here is based on a multivariable PI control, which ensures the applicability and performance of the proposed controller in engineering practice. With the linearized delay uncertainties characterized by polytopic inclusions, a delay-free closed-loop augmented system is established for the IMT powertrain system under discrete-time framework. The proposed controller design problem is then converted to a static output feedback (SOF) controller design problem where the feedback control gains are obtained by solving a set of linear matrix inequalities (LMIs). The effectiveness as well as robustness of the proposed controller is demonstrated by comparing its performance against that of a conventional PI controller.

  19. Robust current control-based generalized predictive control with sliding mode disturbance compensation for PMSM drives.

    Science.gov (United States)

    Liu, Xudong; Zhang, Chenghui; Li, Ke; Zhang, Qi

    2017-11-01

    This paper addresses the current control of permanent magnet synchronous motor (PMSM) for electric drives with model uncertainties and disturbances. A generalized predictive current control method combined with sliding mode disturbance compensation is proposed to satisfy the requirement of fast response and strong robustness. Firstly, according to the generalized predictive control (GPC) theory based on the continuous time model, a predictive current control method is presented without considering the disturbance, which is convenient to be realized in the digital controller. In fact, it's difficult to derive the exact motor model and parameters in the practical system. Thus, a sliding mode disturbance compensation controller is studied to improve the adaptiveness and robustness of the control system. The designed controller attempts to combine the merits of both predictive control and sliding mode control, meanwhile, the controller parameters are easy to be adjusted. Lastly, the proposed controller is tested on an interior PMSM by simulation and experiment, and the results indicate that it has good performance in both current tracking and disturbance rejection. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  20. OpenRRArch: An open, robust and reliable architecture for controlling autonomous robots

    Directory of Open Access Journals (Sweden)

    Fredy Hernán Martínez Sarmiento

    2017-01-01

    Full Text Available Context: The control and navigation systems of autonomous robots constitute a dynamic field of research in robotics. The possible solutions to problems are often evaluated with laboratory prototypes in order to determine their real performance. We propose in this paper an architecture for the design and development of robotic systems (particularly autonomous multi-robot Systems that facilitate the work in laboratory due to an open robust and reliable architecture. Method: The architecture is supported in open source hardware and software. The operation and communication strategy is characterized by a low consumption of resources, both in processing and communication, and real-time operation. As developement platform and Operating System, we used Linux: the communication scheme and the embedded systems run on a 32-bit processor, with a 16-bit instruction set (not ARM, but with Harvard architecture, at 80 MHz (Tensilica Xtensa LX106 for the implementation of the agents. The tools used allow the solution to be bothe efficient and inexpensive. Results: The architecture has been successfully applied in the implementation of a strategy of navigation for a set of small autonomous robots. A set of robots were provided with wireless communication capability, minimum capacity of environmental sensing (obstacle detection and a navigation algorithm based on population sizes (mimicking the bacterial Quorum Sensing. The system is implemented with great ease, demonstrating both the viability of the navigation strategy and the versatility, robustness and scalability of the OpenRRArch architecture. Conclusions: The proposed architecture constitutes a solution for the construction of distributed control systems, in particular multi-agent robotic systems. It enables the rapid, low-cost and high-performance implementation of systems with real-time cooperation and communication capabilities. The architecture allows the integration of agents with different processing

  1. Design of Active Queue Management for Robust Control on Access Router for Heterogeneous Networks

    Directory of Open Access Journals (Sweden)

    Åhlund Christer

    2011-01-01

    Full Text Available The Internet architecture is a packet switching technology that allows dynamic sharing of bandwidth among different flows with in an IP network. Packets are stored and forwarded from one node to the next until reaching their destination. Major issues in this integration are congestion control and how to meet different quality of service requirements associated with various services. In other words streaming media quality degrades with increased packet delay and jitter caused by network congestion. To mitigate the impact of network congestion, various techniques have been used to improve multimedia quality and one of those techniques is Active Queue Management (AQM. Access routers require a buffer to hold packets during times of congestion. A large buffer can absorb the bursty arrivals, and this tends to increase the link utilizations but results in higher queuing delays. Traffic burstiness has a considerable negative impact on network performance. AQM is now considered an effective congestion control mechanism for enhancing transport protocol performance over wireless links. In order to have good link utilization, it is necessary for queues to adapt to varying traffic loads. This paper considers a particular scheme which is called Adaptive AQM (AAQM and studies its performance in the presence of feedback delays and its ability to maintain a small queue length as well as its robustness in the presence of traffic burstiness. The paper also presents a method based on the well-known Markov Modulated Poisson Process (MPP to capture traffic burstiness and buffer occupancy. To demonstrate the generality of the presented method, an analytic model is described and verified by extensive simulations of different adaptive AQM algorithms. The analysis and simulations show that AAQM outperforms the other AQMs with respect to responsiveness and robustness.

  2. Robust digital controllers for uncertain chaotic systems: A digital redesign approach

    Energy Technology Data Exchange (ETDEWEB)

    Ababneh, Mohammad [Department of Controls, FMC Kongsberg Subsea, FMC Energy Systems, Houston, TX 77067 (United States); Barajas-Ramirez, Juan-Gonzalo [CICESE, Depto. De Electronica y Telecomunicaciones, Ensenada, BC, 22860 (Mexico); Chen Guanrong [Centre for Chaos Control and Synchronization, Department of Electronic Engineering, City University of Hong Kong (China); Shieh, Leang S. [Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204-4005 (United States)

    2007-03-15

    In this paper, a new and systematic method for designing robust digital controllers for uncertain nonlinear systems with structured uncertainties is presented. In the proposed method, a controller is designed in terms of the optimal linear model representation of the nominal system around each operating point of the trajectory, while the uncertainties are decomposed such that the uncertain nonlinear system can be rewritten as a set of local linear models with disturbed inputs. Applying conventional robust control techniques, continuous-time robust controllers are first designed to eliminate the effects of the uncertainties on the underlying system. Then, a robust digital controller is obtained as the result of a digital redesign of the designed continuous-time robust controller using the state-matching technique. The effectiveness of the proposed controller design method is illustrated through some numerical examples on complex nonlinear systems--chaotic systems.

  3. Practical robustness measures in multivariable control system analysis. Ph.D. Thesis

    Science.gov (United States)

    Lehtomaki, N. A.

    1981-01-01

    The robustness of the stability of multivariable linear time invariant feedback control systems with respect to model uncertainty is considered using frequency domain criteria. Available robustness tests are unified under a common framework based on the nature and structure of model errors. These results are derived using a multivariable version of Nyquist's stability theorem in which the minimum singular value of the return difference transfer matrix is shown to be the multivariable generalization of the distance to the critical point on a single input, single output Nyquist diagram. Using the return difference transfer matrix, a very general robustness theorem is presented from which all of the robustness tests dealing with specific model errors may be derived. The robustness tests that explicitly utilized model error structure are able to guarantee feedback system stability in the face of model errors of larger magnitude than those robustness tests that do not. The robustness of linear quadratic Gaussian control systems are analyzed.

  4. Robust output tracking control of a laboratory helicopter for automatic landing

    Science.gov (United States)

    Liu, Hao; Lu, Geng; Zhong, Yisheng

    2014-11-01

    In this paper, robust output tracking control problem of a laboratory helicopter for automatic landing in high seas is investigated. The motion of the helicopter is required to synchronise with that of an oscillating platform, e.g. the deck of a vessel subject to wave-induced motions. A robust linear time-invariant output feedback controller consisting of a nominal controller and a robust compensator is designed. The robust compensator is introduced to restrain the influences of parametric uncertainties, nonlinearities and external disturbances. It is shown that robust stability and robust tracking property can be achieved simultaneously. Experimental results on the laboratory helicopter for automatic landing demonstrate the effectiveness of the designed control approach.

  5. Sliding-Mode Control Applied for Robust Control of a Highly Unstable Aircraft

    Science.gov (United States)

    Vetter, Travis Kenneth

    2002-01-01

    An investigation into the application of an observer based sliding mode controller for robust control of a highly unstable aircraft and methods of compensating for actuator dynamics is performed. After a brief overview of some reconfigurable controllers, sliding mode control (SMC) is selected because of its invariance properties and lack of need for parameter identification. SMC is reviewed and issues with parasitic dynamics, which cause system instability, are addressed. Utilizing sliding manifold boundary layers, the nonlinear control is converted to a linear control and sliding manifold design is performed in the frequency domain. An additional feedback form of model reference hedging is employed which is similar to a prefilter and has large benefits to system performance. The effects of inclusion of actuator dynamics into the designed plant is heavily investigated. Multiple Simulink models of the full longitudinal dynamics and wing deflection modes of the forward swept aero elastic vehicle (FSAV) are constructed. Additionally a linear state space models to analyze effects from various system parameters. The FSAV has a pole at +7 rad/sec and is non-minimum phase. The use of 'model actuators' in the feedback path, and varying there design, is heavily investigated for the resulting effects on plant robustness and tolerance to actuator failure. The use of redundant actuators is also explored and improved robustness is shown. All models are simulated with severe failure and excellent tracking, and task dependent handling qualities, and low pilot induced oscillation tendency is shown.

  6. Active Disturbance Rejection Approach for Robust Fault-Tolerant Control via Observer Assisted Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    John Cortés-Romero

    2013-01-01

    Full Text Available This work proposes an active disturbance rejection approach for the establishment of a sliding mode control strategy in fault-tolerant operations. The core of the proposed active disturbance rejection assistance is a Generalized Proportional Integral (GPI observer which is in charge of the active estimation of lumped nonlinear endogenous and exogenous disturbance inputs related to the creation of local sliding regimes with limited control authority. Possibilities are explored for the GPI observer assisted sliding mode control in fault-tolerant schemes. Convincing improvements are presented with respect to classical sliding mode control strategies. As a collateral advantage, the observer-based control architecture offers the possibility of chattering reduction given that a significant part of the control signal is of the continuous type. The case study considers a classical DC motor control affected by actuator faults, parametric failures, and perturbations. Experimental results and comparisons with other established sliding mode controller design methodologies, which validate the proposed approach, are provided.

  7. Robust Speed Tracking Control for a Micro Turbine as a Distributed Energy Resource via Feedback Domination and Disturbance Observer

    Directory of Open Access Journals (Sweden)

    Ancheng Xu

    2017-01-01

    Full Text Available Micro turbine (MT is characterized with complex dynamics, parameter uncertainties, and variable working conditions. In this paper, a novel robust controller is investigated for a single-shaft micro turbine as a distributed energy resource by integrating a feedback domination control technique and a feedforward disturbance compensation. An active estimation process of the mismatched disturbances is firstly enabled by constructing a disturbance observer. Secondly, we adopt a feedback domination technique, rather than popularly used feedback linearization methods, to handle the system nonlinearities. In an explicit way, the composite controllers are then derived by recursive design based on Lyapunov theory while a global input-to-state stability can be guaranteed. Abundant comparison simulation results are provided to demonstrate the effectiveness of the proposed scheme, which not only perform an improved closed-loop control performance comparing to all existing results, but also render a simple control law which will ease its practical implementation.

  8. Two hybrid ARQ error control schemes for near Earth satellite communications

    Science.gov (United States)

    Lin, S.

    1986-01-01

    Two hybrid Automatic Repeat Request (ARQ) error control schemes are proposed for NASA near Earth satellite communications. Both schemes are adaptive in nature, and employ cascaded codes to achieve both high reliability and throughput efficiency for high data rate file transfer.

  9. Design and Simulation of a Distributed Control Scheme for Inter-Destination Media Synchronization

    NARCIS (Netherlands)

    Montagud, M.; Boronat, F.; Stokking, H.M.

    2013-01-01

    Inter-Destination Multimedia Synchronization (IDMS) is a key requirement to enable satisfying group shared media experiences. This paper presents the design and simulation of a Distributed Control Scheme (DCS) for IDMS. In this scheme, geographically dispersed receivers exchange (multicast) RTCP

  10. Integration of Fault Detection and Isolation with Control Using Neuro-fuzzy Scheme

    Directory of Open Access Journals (Sweden)

    A. Asokan

    2009-10-01

    Full Text Available In this paper an algorithms is developed for fault diagnosis and fault tolerant control strategy for nonlinear systems subjected to an unknown time-varying fault. At first, the design of fault diagnosis scheme is performed using model based fault detection technique. The neuro-fuzzy chi-square scheme is applied for fault detection and isolation. The fault magnitude and time of occurrence of fault is obtained through neuro-fuzzy chi-square scheme. The estimated magnitude of the fault magnitude is normalized and used by the feed-forward control algorithm to make appropriate changes in the manipulated variable to keep the controlled variable near its set value. The feed-forward controller acts along with feed-back controller to control the multivariable system. The performance of the proposed scheme is applied to a three- tank process for various types of fault inputs to show the effectiveness of the proposed approach.

  11. A Robust Tracking Control System Design for Autonomous Underwater Vehicles Based on Sliding Mode Control

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Seung Yun [Agency for Defense Development (Korea, Republic of); Lee, Man Hyung [Pusan National University (Korea, Republic of)

    1998-02-01

    In this paper, a robust path tracking and diving control system of Autonomous Underwater Vehicle based on sliding mode control is presented. We have also d signed augmented equivalent control inputs by analyzing the sliding mode with the reaching mode. This can enhance the reaching rate, and improve chattering problems, that is, noise caused by the control plane actuator of the vehicle, which is one of the problems that occur when sliding mode control is used. Also to resolve the steady state error generated in the path tracker under current effect, a modified sliding plane is constructed. Also a redesigned sliding plane and control input using transformation matrix is proposed to do easy design of MIMO depth controller. For state variables that cannot be measured directly, reduced order sliding mode control is used to design an observer. The performance of designed path tracker and depth controller is investigated by computer simulation. The results show that the proposed control system has robust performance to parameter variation, modelling error and disturbance. (author). 12 refs., 14 figs., 1 tab.

  12. A New Hybrid BFOA-PSO Optimization Technique for Decoupling and Robust Control of Two-Coupled Distillation Column Process.

    Science.gov (United States)

    Abdelkarim, Noha; Mohamed, Amr E; El-Garhy, Ahmed M; Dorrah, Hassen T

    2016-01-01

    The two-coupled distillation column process is a physically complicated system in many aspects. Specifically, the nested interrelationship between system inputs and outputs constitutes one of the significant challenges in system control design. Mostly, such a process is to be decoupled into several input/output pairings (loops), so that a single controller can be assigned for each loop. In the frame of this research, the Brain Emotional Learning Based Intelligent Controller (BELBIC) forms the control structure for each decoupled loop. The paper's main objective is to develop a parameterization technique for decoupling and control schemes, which ensures robust control behavior. In this regard, the novel optimization technique Bacterial Swarm Optimization (BSO) is utilized for the minimization of summation of the integral time-weighted squared errors (ITSEs) for all control loops. This optimization technique constitutes a hybrid between two techniques, which are the Particle Swarm and Bacterial Foraging algorithms. According to the simulation results, this hybridized technique ensures low mathematical burdens and high decoupling and control accuracy. Moreover, the behavior analysis of the proposed BELBIC shows a remarkable improvement in the time domain behavior and robustness over the conventional PID controller.

  13. A New Hybrid BFOA-PSO Optimization Technique for Decoupling and Robust Control of Two-Coupled Distillation Column Process

    Directory of Open Access Journals (Sweden)

    Noha Abdelkarim

    2016-01-01

    Full Text Available The two-coupled distillation column process is a physically complicated system in many aspects. Specifically, the nested interrelationship between system inputs and outputs constitutes one of the significant challenges in system control design. Mostly, such a process is to be decoupled into several input/output pairings (loops, so that a single controller can be assigned for each loop. In the frame of this research, the Brain Emotional Learning Based Intelligent Controller (BELBIC forms the control structure for each decoupled loop. The paper’s main objective is to develop a parameterization technique for decoupling and control schemes, which ensures robust control behavior. In this regard, the novel optimization technique Bacterial Swarm Optimization (BSO is utilized for the minimization of summation of the integral time-weighted squared errors (ITSEs for all control loops. This optimization technique constitutes a hybrid between two techniques, which are the Particle Swarm and Bacterial Foraging algorithms. According to the simulation results, this hybridized technique ensures low mathematical burdens and high decoupling and control accuracy. Moreover, the behavior analysis of the proposed BELBIC shows a remarkable improvement in the time domain behavior and robustness over the conventional PID controller.

  14. A New Hybrid BFOA-PSO Optimization Technique for Decoupling and Robust Control of Two-Coupled Distillation Column Process

    Science.gov (United States)

    Mohamed, Amr E.; Dorrah, Hassen T.

    2016-01-01

    The two-coupled distillation column process is a physically complicated system in many aspects. Specifically, the nested interrelationship between system inputs and outputs constitutes one of the significant challenges in system control design. Mostly, such a process is to be decoupled into several input/output pairings (loops), so that a single controller can be assigned for each loop. In the frame of this research, the Brain Emotional Learning Based Intelligent Controller (BELBIC) forms the control structure for each decoupled loop. The paper's main objective is to develop a parameterization technique for decoupling and control schemes, which ensures robust control behavior. In this regard, the novel optimization technique Bacterial Swarm Optimization (BSO) is utilized for the minimization of summation of the integral time-weighted squared errors (ITSEs) for all control loops. This optimization technique constitutes a hybrid between two techniques, which are the Particle Swarm and Bacterial Foraging algorithms. According to the simulation results, this hybridized technique ensures low mathematical burdens and high decoupling and control accuracy. Moreover, the behavior analysis of the proposed BELBIC shows a remarkable improvement in the time domain behavior and robustness over the conventional PID controller. PMID:27807444

  15. Robust motion control of oscillatory-base manipulators h∞-control and sliding-mode-control-based approaches

    CERN Document Server

    Toda, Masayoshi

    2016-01-01

    This book provides readers with alternative robust approaches to control design for an important class of systems characteristically associated with ocean-going vessels and structures. These systems, which include crane vessels, on-board cranes, radar gimbals, and a conductivity temperature and depth winch, are modelled as manipulators with oscillating bases. One design approach is based on the H-infinity control framework exploiting an effective combination of PD control, an extended matrix polytope and a robust stability analysis method with a state-dependent coefficient form. The other is based on sliding-mode control using some novel nonlinear sliding surfaces. The model demonstrates how successful motion control can be achieved by suppressing base oscillations and in the presence of uncertainties. This is important not only for ocean engineering systems in which the problems addressed here originate but more generally as a benchmark platform for robust motion control with disturbance rejection. Researche...

  16. Observerless Scheme for Sensorless Speed Control of PMSM Using Direct Torque Control Method With LP Filter

    Directory of Open Access Journals (Sweden)

    BEKIROGLU, N.

    2010-08-01

    Full Text Available In this study, direct torque control (DTC of a permanent magnet synchronous motor is realized with a sensorless speed control technique without using an observer. Space vector pulse width modulation (SVPWM technique is applied in order to determine the switching sequence of the voltage source inverter. Torque and flux, the main variables of the DTC, are estimated by using the mathematical model of the motor. Estimated torque and flux values are compared with their references in every control cycle. Then, according to the torque and flux demand, the voltage vector is constituted. In the proposed control scheme, speed is estimated by using flux calculations and a PI controller is used to process the torque and flux errors. Furthermore, a low-pass (LP filter is implemented within the proposed system for voltage and current harmonics suppression. The results proved that proposed scheme for the DTC provides the speed control under various torque demands without employing a sensor. The proposed system performs very well for a sensorless operation and effectively eliminates the harmonics due to the LP filter.

  17. Robust absolute stability analysis for interval nonlinear active disturbance rejection based control system.

    Science.gov (United States)

    Li, Jie; Xia, Yuanqing; Qi, Xiaohui; Zhao, Pengpeng

    2017-07-01

    Active disturbance rejection control (ADRC) is a relatively new, quite different but very practical control technology, which shows much promise in replacement of proportion-integration-differentiation (PID) with unmistakable advantage in performance and practicality. This paper mainly concerns with the robust absolute stability of the ADRC based control system with parameter perturbations of the plant, i.e., ADRC based interval control system. Firstly, the system is transformed into a perturbed indirect Lurie system. Then, the Popov criterion and its robust version are presented and some new methods are developed to analyze the (robust) absolute stability for the interval control system. Furthermore, an example is presented to illustrate (robust) absolute stability analysis via the above methods, which verifies the convenience and practicability of these methods and shows the strong stability robustness of ADRC in the presence of parametric uncertainties. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Regulation control and energy management scheme for wireless power transfer

    Science.gov (United States)

    Miller, John M.

    2015-12-29

    Power transfer rate at a charging facility can be maximized by employing a feedback scheme. The state of charge (SOC) and temperature of the regenerative energy storage system (RESS) pack of a vehicle is monitored to determine the load due to the RESS pack. An optimal frequency that cancels the imaginary component of the input impedance for the output signal from a grid converter is calculated from the load of the RESS pack, and a frequency offset f* is made to the nominal frequency f.sub.0 of the grid converter output based on the resonance frequency of a magnetically coupled circuit. The optimal frequency can maximize the efficiency of the power transfer. Further, an optimal grid converter duty ratio d* can be derived from the charge rate of the RESS pack. The grid converter duty ratio d* regulates wireless power transfer (WPT) power level.

  19. Observer-Based Robust Control of Uncertain Switched Fuzzy Systems with Combined Switching Controller

    Directory of Open Access Journals (Sweden)

    Hong Yang

    2013-01-01

    Full Text Available The observer-based robust control for a class of switched fuzzy (SF time-delay systems involving uncertainties and external disturbances is investigated in this paper. A switched fuzzy system, which differs from existing ones, is firstly employed to describe a nonlinear system. Next, a combined switching controller is proposed. The designed controller based on the observer instead of the state information integrates the advantages of both the switching controllers and the supplementary controllers but eliminates their disadvantages. The proposed controller provides good performance during the transient period, and the chattering effect is removed when the system state approaches the origin. Sufficient condition for the solvability of the robust control problem is given for the case that the state of system is not available. Since convex combination techniques are used to derive the delay-independent criteria, some subsystems are allowed to be unstable. Finally, various comparisons of the elaborated examples are conducted to demonstrate the effectiveness of the proposed control design approach.

  20. Chaos suppression via observer based active control scheme: Application to Duffing's oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Lopez, Ricardo [Departamento de Energia, Universidad Autonoma Metropolita-Azcapotzalco, Av. San Pablo No. 180, Reynosa-Tamaulipas, Azcapotzalco 02200, Mexico DF (Mexico)]. E-mail: raguilar@correo.azc.uam.mx; Martinez-Guerra, Rafael [Departamento de Control Automatico, CINVESTAV-IPN, C.P. 07360 Mexico DF (Mexico)

    2007-06-15

    The aim of this paper is the synthesis of a robust control law for chaos suppression of a class of non-linear oscillator with affine control input. A robust state observer based active controller, which provides robustness against model uncertainties and noisy output measurements is proposed. The closed-loop stability for the underlying closed-loop system is done via the regulation and estimation errors dynamics. The performance of the proposed control law is illustrated with numerical simulations. The method is general and can be applied to various non-linear systems which satisfy the conditions required.

  1. Rigorously modeling self-stabilizing fault-tolerant circuits: An ultra-robust clocking scheme for systems-on-chip☆

    Science.gov (United States)

    Dolev, Danny; Függer, Matthias; Posch, Markus; Schmid, Ulrich; Steininger, Andreas; Lenzen, Christoph

    2014-01-01

    We present the first implementation of a distributed clock generation scheme for Systems-on-Chip that recovers from an unbounded number of arbitrary transient faults despite a large number of arbitrary permanent faults. We devise self-stabilizing hardware building blocks and a hybrid synchronous/asynchronous state machine enabling metastability-free transitions of the algorithm's states. We provide a comprehensive modeling approach that permits to prove, given correctness of the constructed low-level building blocks, the high-level properties of the synchronization algorithm (which have been established in a more abstract model). We believe this approach to be of interest in its own right, since this is the first technique permitting to mathematically verify, at manageable complexity, high-level properties of a fault-prone system in terms of its very basic components. We evaluate a prototype implementation, which has been designed in VHDL, using the Petrify tool in conjunction with some extensions, and synthesized for an Altera Cyclone FPGA. PMID:26516290

  2. Rigorously modeling self-stabilizing fault-tolerant circuits: An ultra-robust clocking scheme for systems-on-chip.

    Science.gov (United States)

    Dolev, Danny; Függer, Matthias; Posch, Markus; Schmid, Ulrich; Steininger, Andreas; Lenzen, Christoph

    2014-06-01

    We present the first implementation of a distributed clock generation scheme for Systems-on-Chip that recovers from an unbounded number of arbitrary transient faults despite a large number of arbitrary permanent faults. We devise self-stabilizing hardware building blocks and a hybrid synchronous/asynchronous state machine enabling metastability-free transitions of the algorithm's states. We provide a comprehensive modeling approach that permits to prove, given correctness of the constructed low-level building blocks, the high-level properties of the synchronization algorithm (which have been established in a more abstract model). We believe this approach to be of interest in its own right, since this is the first technique permitting to mathematically verify, at manageable complexity, high-level properties of a fault-prone system in terms of its very basic components. We evaluate a prototype implementation, which has been designed in VHDL, using the Petrify tool in conjunction with some extensions, and synthesized for an Altera Cyclone FPGA.

  3. Using H∞ to design robust POD controllers for wind power plants

    DEFF Research Database (Denmark)

    Mehmedalic, Jasmin; Knüppel, Thyge; Østergaard, Jacob

    2012-01-01

    ∞ methods and the designed controllers evaluated on both performance and robustness. It is found that the choice of control signal has a large influence on the robustness of the controllers, and the best performance and robustness is found when the converter active power command is used as control signal......Large wind power plants (WPPs) can help to improve small signal stability by increasing the damping of electromechanical modes of oscillation. This can be done by adding a power system oscillation damping (POD) controller to the wind power plants, similar to power system stabilizer (PSS......) controllers on conventional generation. Here two different design methods are evaluated for their suitability in producing a robust power system oscillation damping controller for wind power plants with full-load converter wind turbine generators (WTGs). Controllers are designed using classic PSS design and H...

  4. Hopf Bifurcation Control in a FAST TCP and RED Model via Multiple Control Schemes

    Directory of Open Access Journals (Sweden)

    Dawei Ding

    2016-01-01

    Full Text Available We focus on the Hopf bifurcation control problem of a FAST TCP model with RED gateway. The system gain parameter is chosen as the bifurcation parameter, and the stable region and stability condition of the congestion control model are given by use of the linear stability analysis. When the system gain passes through a critical value, the system loses the stability and Hopf bifurcation occurs. Considering the negative influence caused by Hopf bifurcation, we apply state feedback controller, hybrid controller, and time-delay feedback controller to postpone the onset of undesirable Hopf bifurcation. Numerical simulations show that the hybrid controller is the most sensitive method to delay the Hopf bifurcation with identical parameter conditions. However, nonlinear state feedback control and time-delay feedback control schemes have larger control parameter range in the Internet congestion control system with FAST TCP and RED gateway. Therefore, we can choose proper control method based on practical situation including unknown conditions or parameter requirements. This paper plays an important role in setting guiding system parameters for controlling the FAST TCP and RED model.

  5. Robust Adaptive PID Controller for a Class of Uncertain Nonlinear Systems: An Application for Speed Tracking Control of an SI Engine

    Directory of Open Access Journals (Sweden)

    Tossaporn Chamsai

    2015-01-01

    Full Text Available The sliding mode control (SMC technique with a first-order low-pass filter (LPF is incorporated with a new adaptive PID controller. It is proposed for tracking control of an uncertain nonlinear system. In the proposed control scheme, the adaptation law is able to update the PID controller online during the control process within a short period. The chattering phenomenon of the SMC can be alleviated by incorporation of a first-order LPF, while the robustness of the control system is similar to that of the sliding mode. In the closed-loop control analysis, the convergence condition in the reaching phase and the existence condition of the sliding mode were analyzed. The stability of the closed-loop control is guaranteed in the sense of Lyapunov’s direct method. The simulations and experimental applications of a speed tracking control of a spark ignition (SI engine via electronic throttle valve control architecture are provided to verify the effectiveness and the feasibility of the proposed control scheme.

  6. An intelligent control scheme for precise tip-motion control in atomic force microscopy.

    Science.gov (United States)

    Wang, Yanyan; Hu, Xiaodong; Xu, Linyan

    2016-01-01

    The paper proposes a new intelligent control method to precisely control the tip motion of the atomic force microscopy (AFM). The tip moves up and down at a high rate along the z direction during scanning, requiring the utilization of a rapid feedback controller. The standard proportional-integral (PI) feedback controller is commonly used in commercial AFMs to enable topography measurements. The controller's response performance is determined by the set of the proportional (P) parameter and the integral (I) parameter. However, the two parameters cannot be automatically altered simultaneously according to the scanning speed and the surface topography during continuors scanning, leading to an inaccurate measurement. Thus a new intelligent controller combining the fuzzy controller and the PI controller is put forward in the paper. The new controller automatically selects the most appropriate PI parameters to achieve a fast response rate on basis of the tracking errors. In the experimental setup, the new controller is realized with a digital signal process (DSP) system, implemented in a conventional AFM system. Experiments are carried out by comparing the new method with the standard PI controller. The results demonstrate that the new method is more robust and effective for the precise tip motion control, corresponding to the achievement of a highly qualified image by shortening the response time of the controller. © Wiley Periodicals, Inc.

  7. Robust high-performance control for robotic manipulators

    Science.gov (United States)

    Seraji, Homayoun (Inventor)

    1989-01-01

    Model-based and performance-based control techniques are combined for an electrical robotic control system. Thus, two distinct and separate design philosophies were merged into a single control system having a control law formulation including two distinct and separate components, each of which yields a respective signal componet that is combined into a total command signal for the system. Those two separate system components include a feedforward controller and feedback controller. The feedforward controller is model-based and contains any known part of the manipulator dynamics that can be used for on-line control to produce a nominal feedforward component of the system's control signal. The feedback controller is performance-based and consists of a simple adaptive PID controller which generates an adaptive control signal to complement the nomical feedforward signal.

  8. Nonlinear robust control of hypersonic aircrafts with interactions between flight dynamics and propulsion systems.

    Science.gov (United States)

    Li, Zhaoying; Zhou, Wenjie; Liu, Hao

    2016-09-01

    This paper addresses the nonlinear robust tracking controller design problem for hypersonic vehicles. This problem is challenging due to strong coupling between the aerodynamics and the propulsion system, and the uncertainties involved in the vehicle dynamics including parametric uncertainties, unmodeled model uncertainties, and external disturbances. By utilizing the feedback linearization technique, a linear tracking error system is established with prescribed references. For the linear model, a robust controller is proposed based on the signal compensation theory to guarantee that the tracking error dynamics is robustly stable. Numerical simulation results are given to show the advantages of the proposed nonlinear robust control method, compared to the robust loop-shaping control approach. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Robust EMG sensing system based on data fusion for myoelectric control of a robotic arm

    Directory of Open Access Journals (Sweden)

    Soria Carlos M

    2009-02-01

    Full Text Available Abstract Background Myoelectric control of a robotic manipulator may be disturbed by failures due to disconnected electrodes, interface impedance changes caused by movements, problems in the recording channel and other various noise sources. To correct these problems, this paper presents two fusing techniques, Variance Weighted Average (VWA and Decentralized Kalman Filter (DKF, both based on the myoelectric signal variance as selecting criterion. Methods Tested in five volunteers, a redundant arrangement was obtained with two pairs of electrodes for each recording channel. The myoelectric signals were electronically amplified, filtered and digitalized, while the processing, fusion algorithms and control were implemented in a personal computer under MATLAB® environment and in a Digital Signal Processor (DSP. The experiments used an industrial robotic manipulator BOSCH SR-800, type SCARA, with four degrees of freedom; however, only the first joint was used to move the end effector to a desired position, the latter obtained as proportional to the EMG amplitude. Results Several trials, including disconnecting and reconnecting one electrode and disturbing the signal with synthetic noise, were performed to test the fusion techniques. The results given by VWA and DKF were transformed into joint coordinates and used as command signals to the robotic arm. Even though the resultant signal was not exact, the failure was ignored and the joint reference signal never exceeded the workspace limits. Conclusion The fault robustness and safety characteristics of a myoelectric controlled manipulator system were substantially improved. The proposed scheme prevents potential risks for the operator, the equipment and the environment. Both algorithms showed efficient behavior. This outline could be applied to myoelectric control of prosthesis, or assistive manipulators to better assure the system functionality when electrode faults or noisy environment are present.

  10. Robust EMG sensing system based on data fusion for myoelectric control of a robotic arm.

    Science.gov (United States)

    López, Natalia M; di Sciascio, Fernando; Soria, Carlos M; Valentinuzzi, Max E

    2009-02-25

    Myoelectric control of a robotic manipulator may be disturbed by failures due to disconnected electrodes, interface impedance changes caused by movements, problems in the recording channel and other various noise sources. To correct these problems, this paper presents two fusing techniques, Variance Weighted Average (VWA) and Decentralized Kalman Filter (DKF), both based on the myoelectric signal variance as selecting criterion. Tested in five volunteers, a redundant arrangement was obtained with two pairs of electrodes for each recording channel. The myoelectric signals were electronically amplified, filtered and digitalized, while the processing, fusion algorithms and control were implemented in a personal computer under MATLAB environment and in a Digital Signal Processor (DSP). The experiments used an industrial robotic manipulator BOSCH SR-800, type SCARA, with four degrees of freedom; however, only the first joint was used to move the end effector to a desired position, the latter obtained as proportional to the EMG amplitude. Several trials, including disconnecting and reconnecting one electrode and disturbing the signal with synthetic noise, were performed to test the fusion techniques. The results given by VWA and DKF were transformed into joint coordinates and used as command signals to the robotic arm. Even though the resultant signal was not exact, the failure was ignored and the joint reference signal never exceeded the workspace limits. The fault robustness and safety characteristics of a myoelectric controlled manipulator system were substantially improved. The proposed scheme prevents potential risks for the operator, the equipment and the environment. Both algorithms showed efficient behavior. This outline could be applied to myoelectric control of prosthesis, or assistive manipulators to better assure the system functionality when electrode faults or noisy environment are present.

  11. Indirect robust control of agile missile via Theta-D technique

    Directory of Open Access Journals (Sweden)

    Di Zhou

    2014-09-01

    Full Text Available An agile missile with tail fins and pulse thrusters has continuous and discontinuous control inputs. This brings certain difficulty to the autopilot design and stability analysis. Indirect robust control via Theta-D technique is employed to handle this problem. An acceleration tracking system is formulated based on the nonlinear dynamics of agile missile. Considering the dynamics of actuators, there is an error between actual input and computed input. A robust control problem is formed by treating the error as input uncertainty. The robust control is equivalent to a nonlinear quadratic optimal control of the nominal system with a modified performance index including uncertainty bound. Theta-D technique is applied to solve the nonlinear optimal control problem to obtain the final control law. Numerical results show the effectiveness and robustness of the proposed strategy.

  12. Robust H infinity control design for the space station with structured parameter uncertainty

    Science.gov (United States)

    Byun, Kuk-Whan; Wie, Bong; Geller, David; Sunkel, John

    1992-01-01

    A robust H-infinity control design methodology and its application to a Space Station attitude and momentum control problem are presented. This new approach incorporates nonlinear multi-parameter variations in the state-space formulation of H-infinity control theory. An application of this robust H-infinity control synthesis technique to the Space Station control problem yields a remarkable result in stability robustness with respect to the moments-of-inertia variation of about 73% in one of the structured uncertainty directions. The performance and stability of this new robust H-infinity controller for the Space Station are compared to those of other controllers designed using a standard linear-quadratic-regulator synthesis technique.

  13. Robust output feedback H-infinity control and filtering for uncertain linear systems

    CERN Document Server

    Chang, Xiao-Heng

    2014-01-01

    "Robust Output Feedback H-infinity Control and Filtering for Uncertain Linear Systems" discusses new and meaningful findings on robust output feedback H-infinity control and filtering for uncertain linear systems, presenting a number of useful and less conservative design results based on the linear matrix inequality (LMI) technique. Though primarily intended for graduate students in control and filtering, the book can also serve as a valuable reference work for researchers wishing to explore the area of robust H-infinity control and filtering of uncertain systems. Dr. Xiao-Heng Chang is a Professor at the College of Engineering, Bohai University, China.

  14. Control charts for location based on different sampling schemes

    NARCIS (Netherlands)

    Mehmood, R.; Riaz, M.; Does, R.J.M.M.

    2013-01-01

    Control charts are the most important statistical process control tool for monitoring variations in a process. A number of articles are available in the literature for the X̄ control chart based on simple random sampling, ranked set sampling, median-ranked set sampling (MRSS), extreme-ranked set

  15. Robust vibration control at critical resonant modes using indirect-driven self-sensing actuation in mechatronic systems.

    Science.gov (United States)

    Hong, Fan; Pang, Chee Khiang

    2012-11-01

    This paper presents an improved indirect-driven self-sensing actuation circuit for robust vibration control of piezoelectrically-actuated flexible structures in mechatronic systems. The circuit acts as a high-pass filter and provides better self-sensing strain signals with wider sensing bandwidth and higher signal-to-noise ratio. An adaptive non-model-based control is used to compensate for the structural vibrations using the strain signals from the circuit. The proposed scheme is implemented in a PZT-actuated suspension of a commercial dual-stage hard disk drive. Experimental results show improvements of 50% and 75% in the vibration suppression at 5.4kHz and 21kHz respectively, compared to the conventional PI control. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  16. Robust Adaptive Speed Control of Induction Motor Drives

    DEFF Research Database (Denmark)

    Bidstrup, N.

    adaptive speed control of the CVC drive. A direct truly adaptive speed controller has been implemented. The adaptive controller is a moving Average Self-Tuning Regulator which is abbreviated MASTR throughout the thesis. Two practical implementations of this controller were proposed. They were denoted MASTR......This thesis concerns speed control of current vector controlled induction motor drives (CVC drives). The CVC drive is an existing prototype drive developed by Danfoss A/S, Transmission Division. Practical tests have revealed that the open loop dynamical properties of the CVC drive are highly...... dependent of the operating point, which is characterised by the speed and load. If the requirements to the controller performance is large, then it is difficult to maintain specified controller performance with a fixed controller, because of the open loop variations. An auto-tuner based on least squares...

  17. LMI–based robust controller design approach in aircraft multidisciplinary design optimization problem

    Directory of Open Access Journals (Sweden)

    Qinghua Zeng

    2015-07-01

    Full Text Available This article proposes a linear matrix inequality–based robust controller design approach to implement the synchronous design of aircraft control discipline and other disciplines, in which the variation in design parameters is treated as equivalent perturbations. Considering the complicated mapping relationships between the coefficient arrays of aircraft motion model and the aircraft design parameters, the robust controller designed is directly based on the variation in these coefficient arrays so conservative that the multidisciplinary design optimization problem would be too difficult to solve, or even if there is a solution, the robustness of design result is generally poor. Therefore, this article derives the uncertainty model of disciplinary design parameters based on response surface approximation, converts the design problem of the robust controller into a problem of solving a standard linear matrix inequality, and theoretically gives a less conservative design method of the robust controller which is based on the variation in design parameters. Furthermore, the concurrent subspace approach is applied to the multidisciplinary system with this kind of robust controller in the design loop. A multidisciplinary design optimization of a tailless aircraft as example is shown that control discipline can be synchronous optimal design with other discipline, especially this method will greatly reduce the calculated amount of multidisciplinary design optimization and make multidisciplinary design optimization results more robustness of flight performance.

  18. Robust controller design of the integrated direct drive volume control architecture for steering systems.

    Science.gov (United States)

    Shen, Wei; Pang, Yu; Jiang, Jihai

    2017-06-08

    Recently, much effort has been directed toward the large throttling loss and low efficiency of the valve control system widely applied in steering system of ships. This paper presents an Integrated Direct-Drive Volume Control (IDDVC) electro-hydraulic servo system with the advantages of high efficiency and energy conservation. Firstly, the simulation model of IDDVC is improved by software AMESim, including the nonlinear interaction of the motor-pump and the oil supply ignored by traditional transfer function model. Then, by establishing discrete state equations, a controller based on robust sliding control strategy has been designed to enhance the practicality and real-time performance. Finally, the accuracy of the model and the effectiveness of the controller are proved through the experiments which are conducted after constructing the IDDVC prototype. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Robust Adaptive Speed Control of Induction Motor Drives

    DEFF Research Database (Denmark)

    Bidstrup, N.

    This thesis concerns speed control of current vector controlled induction motor drives (CVC drives). The CVC drive is an existing prototype drive developed by Danfoss A/S, Transmission Division. Practical tests have revealed that the open loop dynamical properties of the CVC drive are highly...... adaptive speed control of the CVC drive. A direct truly adaptive speed controller has been implemented. The adaptive controller is a moving Average Self-Tuning Regulator which is abbreviated MASTR throughout the thesis. Two practical implementations of this controller were proposed. They were denoted MASTR...

  20. Robust Coordinated Control Algorithm for Multiple Marine Vessels with External Disturbances

    Directory of Open Access Journals (Sweden)

    Weixue Liu

    2013-01-01

    Full Text Available The problem of coordinated control for multiple marine vessels in the presence of external disturbances is considered in this paper. A robust coordinated control algorithm is proposed for multiple marine vessels. The proposed robust coordinated control algorithm is divided into two parts. The first part develops an extended state observer to estimate the disturbances of marine vessels. The second part presents a robust coordinated control algorithm based on the output of the extended state observer. Furthermore, the robust coordinated control algorithm is designed using the dynamic surface control method. In light of the leader-follower strategy, the trajectory for each vessel is defined according to the desired trajectory of the assigned leader and the relative distance with respect to the leader. The effectiveness of the proposed coordination algorithm is demonstrated by the simulation results.

  1. An Optimal Control Scheme to Minimize Loads in Wind Farms

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2012-01-01

    This work presents a control algorithm for wind farms that optimizes the power production of the farm and helps to increase the lifetime of wind turbines components. The control algorithm is a centralized approach, and it determines the power reference signals for individual wind turbines...... such that the structural loads of the wind turbines in low frequencies are reduced. The controller is relatively easy to implement on a wind farm, and in here the results of simulating the controller on a small wind farm is presented....

  2. Robust adaptive fuzzy neural tracking control for a class of unknown ...

    Indian Academy of Sciences (India)

    In this paper, an adaptive fuzzy neural controller (AFNC) for a class of unknown chaotic systems is proposed. The proposed AFNC is comprised of a fuzzy neural controller and a robust controller. The fuzzy neural controller including a fuzzy neural network identifier (FNNI) is the principal controller. The FNNI is used for ...

  3. A hybrid iterative scheme for optimal control problems governed by ...

    African Journals Online (AJOL)

    MRT

    obtaining approximate solutions of optimal control problems governed by some Fredholm integral equations. By some numerical ... Trace of numerical approaches in optimal control problems can be found in many applications and academic literatures. ...... Progress In Electromagnetics Research 78: 361–376. Ghasemi, M.

  4. Adaptive control schemes for mobile robot formations with triangularised structures

    NARCIS (Netherlands)

    Guo, J.; Lin, Z.; Cao, M.; Yan, G.

    The study investigates the leader-follower formation control problem, for which the objective is to control a group of robots such that they move as a rigid formation with a prescribed constant velocity. It is assumed in the study that there are two leader robots, who are the only robots in the

  5. Analysis of Contracting Processes, Internal Controls, and Procurement Fraud Schemes

    Science.gov (United States)

    2013-06-01

    of the Treadway Commission ( COSO ). (1992). Internal control-integrated framework . Retrieved from http://www.coso.org Competition in Contracting...United States COR Contracting Officer Representative COSO Committee of Sponsoring Organizations DAU Defense Acquisition University DAWIA Defense...adopted from the Committee of Sponsoring Organizations of the Treadway Commission ( COSO ) (1992). There are five components: control environment, risk

  6. Algorithms for Optimal Model Distributions in Adaptive Switching Control Schemes

    NARCIS (Netherlands)

    Ghosh, D.; Baldi, S.

    2016-01-01

    Several multiple model adaptive control architectures have been proposed in the literature. Despite many advances in theory, the crucial question of how to synthesize the pairs model/controller in a structurally optimal way is to a large extent not addressed. In particular, it is not clear how to

  7. Robust Control of the Air to Fuel Ratio in Spark Ignition Engines with Delayed Measurements from a UEGO Sensor

    Directory of Open Access Journals (Sweden)

    Javier Espinoza-Jurado

    2015-01-01

    Full Text Available A precise control of the normalized air to fuel ratio in spark ignition engines is an essential task. To achieve this goal, in this work we take into consideration the time delay measurement presented by the universal exhaust gas oxygen sensor along with uncertainties in the volumetric efficiency. For that purpose, observers are designed by means of a super-twisting sliding mode estimation scheme. Also two control schemes based on a general nonlinear model and a similar nonlinear affine representation for the dynamics of the normalized air to fuel ratio were designed in this work by using the super-twisting sliding mode methodology. Such dynamics depends on the control input, that is, the injected fuel mass flow, its time derivative, and its reciprocal. The two latter terms are estimated by means of a robust sliding mode differentiator. The observers and controllers are designed based on an isothermal mean value engine model. Numeric and hardware in the loop simulations were carried out with such model, where parameters were taken from a real engine. The obtained results show a good output tracking and rejection of disturbances when the engine is closed loop with proposed control methods.

  8. Analysis of Interval Control System Robust Quality Indices on the Base of Root and Coefficient Methods

    Science.gov (United States)

    Gayvoronskiy, S. A.; Ezangina, T.; Khozhaev, I.

    2017-09-01

    Considered paper is dedicated to interval control system quality analysis with the help of root locus method and method of coefficient estimates. On the base of the first method, an algorithm of determining examinable vertices of interval characteristic polynomial coefficients polytope, which images determine robust root quality indices. On the base of coefficients method, sufficient conditions, linking coefficients of interval characteristic polynomial coefficients with quantitative estimates of robust root quality indices. With the help of both developed approaches, a robust control quality of unmanned underwater vehicle control systems was analyzed.

  9. Robust Distributed Model Predictive Load Frequency Control of Interconnected Power System

    Directory of Open Access Journals (Sweden)

    Xiangjie Liu

    2013-01-01

    Full Text Available Considering the load frequency control (LFC of large-scale power system, a robust distributed model predictive control (RDMPC is presented. The system uncertainty according to power system parameter variation alone with the generation rate constraints (GRC is included in the synthesis procedure. The entire power system is composed of several control areas, and the problem is formulated as convex optimization problem with linear matrix inequalities (LMI that can be solved efficiently. It minimizes an upper bound on a robust performance objective for each subsystem. Simulation results show good dynamic response and robustness in the presence of power system dynamic uncertainties.

  10. Generalized ESO and Predictive Control Based Robust Autopilot Design

    Directory of Open Access Journals (Sweden)

    Bhavnesh Panchal

    2016-01-01

    Full Text Available A novel continuous time predictive control and generalized extended state observer (GESO based acceleration tracking pitch autopilot design is proposed for a tail controlled, skid-to-turn tactical missile. As the dynamics of missile are significantly uncertain with mismatched uncertainty, GESO is employed to estimate the state and uncertainty in an integrated manner. The estimates are used to meet the requirement of state and to robustify the output tracking predictive controller designed for nominal system. Closed loop stability for the controller-observer structure is established. An important feature of the proposed design is that it does not require any specific information about the uncertainty. Also the predictive control design yields the feedback control gain and disturbance compensation gain simultaneously. Effectiveness of GESO in estimation of the states and uncertainties and in robustifying the predictive controller in the presence of parametric uncertainties, external disturbances, unmodeled dynamics, and measurement noise is illustrated by simulation.

  11. Distributed Consensus-Based Robust Adaptive Formation Control for Nonholonomic Mobile Robots with Partial Known Dynamics

    Directory of Open Access Journals (Sweden)

    Zhaoxia Peng

    2014-01-01

    Full Text Available This paper investigates the distributed consensus-based robust adaptive formation control for nonholonomic mobile robots with partially known dynamics. Firstly, multirobot formation control problem has been converted into a state consensus problem. Secondly, the practical control strategies, which incorporate the distributed kinematic controllers and the robust adaptive torque controllers, are designed for solving the formation control problem. Thirdly, the specified reference trajectory for the geometric centroid of the formation is assumed as the trajectory of a virtual leader, whose information is available to only a subset of the followers. Finally, numerical results are provided to illustrate the effectiveness of the proposed control approaches.

  12. A Model Reference Adaptive Control/PID Compound Scheme on Disturbance Rejection for an Aerial Inertially Stabilized Platform

    Directory of Open Access Journals (Sweden)

    Xiangyang Zhou

    2016-01-01

    Full Text Available This paper describes a method to suppress the effect of nonlinear and time-varying mass unbalance torque disturbance on the dynamic performances of an aerial inertially stabilized platform (ISP. To improve the tracking accuracy and robustness of the ISP, a compound control scheme based on both of model reference adaptive control (MRAC and PID control methods is proposed. The dynamic model is first developed which reveals the unbalance torque disturbance with the characteristic of being nonlinear and time-varying. Then, the MRAC/PID compound controller is designed, in which the PID parameters are adaptively adjusted based on the output errors between the reference model and the actual system. In this way, the position errors derived from the prominent unbalance torque disturbance are corrected in real time so that the tracking accuracy is improved. To verify the method, the simulations and experiments are, respectively, carried out. The results show that the compound scheme has good ability in mass unbalance disturbance rejection, by which the system obtains higher stability accuracy compared with the PID method.

  13. Plug and Play Robust Distributed Control with Ellipsoidal Parametric Uncertainty System

    Directory of Open Access Journals (Sweden)

    Hong Wang-jian

    2016-01-01

    Full Text Available We consider a continuous linear time invariant system with ellipsoidal parametric uncertainty structured into subsystems. Since the design of a local controller uses only information on a subsystem and its neighbours, we combine the plug and play idea and robust distributed control to propose one distributed control strategy for linear system with ellipsoidal parametric uncertainty. Firstly for linear system with ellipsoidal parametric uncertainty, a necessary and sufficient condition for robust state feedback control is proposed by means of linear matrix inequality. If this necessary and sufficient condition is satisfied, this robust state feedback gain matrix can be easily derived to guarantee robust stability and prescribed closed loop performance. Secondly the plug and play idea is introduced in the design process. Finally by one example of aircraft flutter model parameter identification, the efficiency of the proposed control strategy can be easily realized.

  14. Robust receding horizon control for networked and distributed nonlinear systems

    CERN Document Server

    Li, Huiping

    2017-01-01

    This book offers a comprehensive, easy-to-understand overview of receding-horizon control for nonlinear networks. It presents novel general strategies that can simultaneously handle general nonlinear dynamics, system constraints, and disturbances arising in networked and large-scale systems and which can be widely applied. These receding-horizon-control-based strategies can achieve sub-optimal control performance while ensuring closed-loop stability: a feature attractive to engineers. The authors address the problems of networked and distributed control step-by-step, gradually increasing the level of challenge presented. The book first introduces the state-feedback control problems of nonlinear networked systems and then studies output feedback control problems. For large-scale nonlinear systems, disturbance is considered first, then communication delay separately, and lastly the simultaneous combination of delays and disturbances. Each chapter of this easy-to-follow book not only proposes and analyzes novel ...

  15. Reliable, Efficient, and Power Optimized Control-Channel Selection Scheme for Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Saleem Aslam

    2013-01-01

    Full Text Available This paper presents a centralized control-channel selection scheme for cognitive radio networks (CRNs by exploiting the variation in the spectrum across capacity, occupancy, and error rate. We address the fundamental challenges in the design of the control-channel for CRNs: (1 random licensed users (LUs activity and (2 the economical and vulnerability concerns for a dedicated control-channel. We develop a knapsack problem (KP based reliable, efficient, and power optimized (REPO control-channel selection scheme with an optimal data rate, bit error rate (BER, and idle time. Moreover, we introduce the concept of the backup channels in the context of control-channel selection, which assists the CRs to quickly move on to the next stable channel in order to cater for the sudden appearance of LUs. Based on the KP and its dynamic programming solution, simulation results show that the proposed scheme is highly adaptable and resilient to random LU activity. The REPO scheme reduces collisions with the LUs, minimizes the alternate channel selection time, and reduces the bit error rate (BER. Moreover, it reduces the power consumed during channel switching and provides a performance, that is, competitive with those schemes that are using a static control-channel for the management of control traffic in CRNs.

  16. Design and deployment of secure, robust, and resilient SDN Controllers

    OpenAIRE

    Scott-Hayward, Sandra

    2015-01-01

    The scale of the Software-Defined Network (SDN) Controller design problem has become apparent with the expansion of SDN deployments. Initial SDN deployments were small-scale, single controller environments for research and usecase testing. Today, enterprise deployments requiring multiple controllers are gathering momentum e.g. Google’s backbone network, Microsoft’s public cloud, and NTT’s edge gateway. Third-party applications are also becoming available e.g. HP SDN App Store. The increase in...

  17. Pre-Allocation Based Flow Control Scheme for Networks-On-Chip

    Science.gov (United States)

    Lin, Shijun; Su, Li; Su, Haibo; Jin, Depeng; Zeng, Lieguang

    Based on the traffic predictability characteristic of Networks-on-Chip (NoC), we propose a pre-allocation based flow control scheme to improve the performance of NoC. In this scheme, routes are pre-allocated and the injection rates of all routes are regulated at the traffic sources according to the average available bandwidths in the links. Then, the number of packets in the network is decreased and thus, the congestion probability is reduced and the communication performance is improved. Simulation results show that this scheme greatly increases the throughput and cuts down the average latency with little area and energy overhead, compared with the switch-to-switch flow control scheme.

  18. Research on a New Control Scheme of Photovoltaic Grid Power Generation System

    Directory of Open Access Journals (Sweden)

    Dong-Hui Li

    2014-01-01

    Full Text Available A new type of photovoltaic grid power generation system control scheme to solve the problems of the conventional photovoltaic grid power generation systems is presented. To aim at the oscillation and misjudgment of traditional perturbation observation method, an improved perturbation observation method comparing to the next moment power is proposed, combining with BOOST step-up circuit to realize the maximum power tracking. To counter the harmonic pollution problem in photovoltaic grid power generation system, the deadbeat control scheme in fundamental wave synchronous frequency rotating coordinate system of power grid is presented. A parameter optimization scheme based on positive feedback of active frequency shift island detection to solve the problems like the nondetection zone due to the import of disturbance in traditional island detection method is proposed. Finally, the results in simulation environment by MATLAB/Simulink simulation and experiment environment verify the validity and superiority of the proposed scheme.

  19. Robust controller for synchronous generator with local load via VSC

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera-Vazquez, J. [Universidad de Guadalajara, Centro Universitario de Ciencias Exactas e Ingenierias, Departamento de Electronica, Av. Revolucion No. 1500, Modulo ' ' O' ' , Apdo. Postal 44840, Guadalajara Jalisco (Mexico); Loukianov, Alexander G.; Canedo, Jose M. [Centro de Investigacion y de Estudios Avanzados del IPN, Apdo. Postal 31-438, Plaza La Luna, C. P. 44550, Guadalajara, Jalisco (Mexico); Utkin, Vadim I. [Department of Electrical Engineering, The Ohio-State University, Columbus, OH 43210-1272 (United States)

    2007-05-15

    The objective of this paper is to design a nonlinear observer-based excitation controller for power system comprising a single synchronous generator connected to an infinite bus with local load. The controller proposed is based on the using first singular perturbation systems concepts and then Sliding Mode Control technique combining with Block Control Principle. To reduce ''chattering'' a nonlinear observer with estimation of the mechanical torque and rotor fluxes is designed. This combined approach enables to compensate the inherent nonlinearities of the generator and to reject external disturbances. (author)

  20. Resilient Control under Denial-of-Service:Robust Design

    NARCIS (Netherlands)

    Feng, Shuai; Tesi, Pietro

    2016-01-01

    In this paper, we study networked control systems in the presence of Denial-of-Service (DoS) attacks, namely attacks that prevent transmissions over the communication network. The control objective is to maximize frequency and duration of the DoS attacks under which closed-loop stability is not

  1. Hard and Soft Sub-Time-Optimal Robust Controllers

    DEFF Research Database (Denmark)

    Kulczycki, Piotr; Wisniewski, Rafal; Kowalski, Piotr

    2010-01-01

    In many applicational tasks of motion control – fundamental for research in robotics – problems associated with uncertain and/or varying load (a mass or moment of inertia) can present a substantial difficulty during the synthesis of practical controlling systems. The random concept, where the loa...

  2. Robust, Optimal, Predictive, and Integrated Road Traffic Control : Research proposal

    NARCIS (Netherlands)

    Van de Weg, G.S.; Hegyi, A.; Hoogendoorn, S.P.

    2014-01-01

    The development of control strategies for traffic lights, ramp metering installations, and variable speed limits to improve the throughput of road traffic networks can contribute to a more efficient use of road networks. In this project, a hierarchical controller will be developed for the

  3. Robust Point Location Estimators for the EWMA Control Chart

    NARCIS (Netherlands)

    Zwetsloot, I.M.; Schoonhoven, M.; Does, R.J.M.M.

    2016-01-01

    In practice, the EWMA control chart for process monitoring is based on parameters estimated from a retrospective data set representing the process characteristic under study. This data set may contain contaminated observations, which in turn can affect the estimates and hence the control chart’s

  4. Performance analysis of joint diversity combining, adaptive modulation, and power control schemes

    KAUST Repository

    Qaraqe, Khalid A.

    2011-01-01

    Adaptive modulation and diversity combining represent very important adaptive solutions for future generations of wireless communication systems. Indeed, in order to improve the performance and the efficiency of these systems, these two techniques have been recently used jointly in new schemes named joint adaptive modulation and diversity combining (JAMDC) schemes. Considering the problem of finding low hardware complexity, bandwidth-efficient, and processing-power efficient transmission schemes for a downlink scenario and capitalizing on some of these recently proposed JAMDC schemes, we propose and analyze in this paper three joint adaptive modulation, diversity combining, and power control (JAMDCPC) schemes where a constant-power variable-rate adaptive modulation technique is used with an adaptive diversity combining scheme and a common power control process. More specifically, the modulation constellation size, the number of combined diversity paths, and the needed power level are jointly determined to achieve the highest spectral efficiency with the lowest possible processing power consumption quantified in terms of the average number of combined paths, given the fading channel conditions and the required bit error rate (BER) performance. In this paper, the performance of these three JAMDCPC schemes is analyzed in terms of their spectral efficiency, processing power consumption, and error-rate performance. Selected numerical examples show that these schemes considerably increase the spectral efficiency of the existing JAMDC schemes with a slight increase in the average number of combined paths for the low signal-to-noise ratio range while maintaining compliance with the BER performance and a low radiated power which yields to a substantial decrease in interference to co-existing users and systems. © 2011 IEEE.

  5. A low order adaptive control scheme for hydraulic servo systems

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Pedersen, Henrik Clemmensen; Bech, Michael Møller

    2015-01-01

    This paper deals with high-performance position control of hydraulics servo systems in general. The hydraulic servo system used is a two link robotic manipulator actuated by two hydraulic servo cylinders. A non-linear model of the hydraulic system and a Newton-Euler based model of the mechanical...

  6. Control and management scheme in a DWDM EPON

    NARCIS (Netherlands)

    Roy, R.; Manhoudt, Gert; Roeloffzen, C.G.H.; van Etten, Wim

    2006-01-01

    Passive Optical Networks (PONs) are a preferred architecture for distribution of bandwidth in the access network. The BSIK Freeband Broadband Photonics Project(BBP) looks at the design of a flexible DWDM PON which can be used to increase the bandwidth provided to the user. We present a control and

  7. A Robust Design Methodology for Optimal Microscale Secondary Flow Control in Compact Inlet Diffusers

    Science.gov (United States)

    Anderson, Bernhard H.; Keller, Dennis J.

    2001-01-01

    It is the purpose of this study to develop an economical Robust design methodology for microscale secondary flow control in compact inlet diffusers. To illustrate the potential of economical Robust Design methodology, two different mission strategies were considered for the subject inlet, namely Maximum Performance and Maximum HCF Life Expectancy. The Maximum Performance mission maximized total pressure recovery while the Maximum HCF Life Expectancy mission minimized the mean of the first five Fourier harmonic amplitudes, i.e., 'collectively' reduced all the harmonic 1/2 amplitudes of engine face distortion. Each of the mission strategies was subject to a low engine face distortion constraint, i.e., DC60designed over a twenty degree angle-of-incidence range. The Optimal Robust installation used economical Robust Design methodology to arrive at a single design which operated over the entire angle-of-incident range (open loop control). The Optimal Adaptive installation optimized all the design parameters at each angle-of-incidence. Thus, the Optimal Adaptive installation would require a closed loop control system to sense a proper signal for each effector and modify that effector device, whether mechanical or fluidic, for optimal inlet performance. In general, the performance differences between the Optimal Adaptive and Optimal Robust installation designs were found to be marginal. This suggests, however, that Optimal Robust open loop installation designs can be very competitive with Optimal Adaptive close loop designs. Secondary flow control in inlets is inherently robust, provided it is optimally designed. Therefore, the new methodology presented in this paper, combined array 'Lower Order' approach to Robust DOE, offers the aerodynamicist a very viable and economical way of exploring the concept of Robust inlet design, where the mission variables are brought directly into the inlet design process and insensitivity or robustness to the mission variables becomes a

  8. Designing for Damage: Robust Flight Control Design using Sliding Mode Techniques

    Science.gov (United States)

    Vetter, T. K.; Wells, S. R.; Hess, Ronald A.; Bacon, Barton (Technical Monitor); Davidson, John (Technical Monitor)

    2002-01-01

    A brief review of sliding model control is undertaken, with particular emphasis upon the effects of neglected parasitic dynamics. Sliding model control design is interpreted in the frequency domain. The inclusion of asymptotic observers and control 'hedging' is shown to reduce the effects of neglected parasitic dynamics. An investigation into the application of observer-based sliding mode control to the robust longitudinal control of a highly unstable is described. The sliding mode controller is shown to exhibit stability and performance robustness superior to that of a classical loop-shaped design when significant changes in vehicle and actuator dynamics are employed to model airframe damage.

  9. A novel and efficient user access control scheme for wireless body area sensor networks

    Directory of Open Access Journals (Sweden)

    Santanu Chatterjee

    2014-07-01

    Full Text Available Wireless body area networks (WBANs can be applied to provide healthcare and patient monitoring. However, patient privacy can be vulnerable in a WBAN unless security is considered. Access to authorized users for the correct information and resources for different services can be provided with the help of efficient user access control mechanisms. This paper proposes a new user access control scheme for a WBAN. The proposed scheme makes use of a group-based user access ID, an access privilege mask, and a password. An elliptic curve cryptography-based public key cryptosystem is used to ensure that a particular legitimate user can only access the information for which he/she is authorized. We show that our scheme performs better than previously existing user access control schemes. Through a security analysis, we show that our scheme is secure against possible known attacks. Furthermore, through a formal security verification using the AVISPA (Automated Validation of Internet Security Protocols and Applications tool, we show that our scheme is also secure against passive and active attacks.

  10. Robust Visual Control of Parallel Robots under Uncertain Camera Orientation

    Directory of Open Access Journals (Sweden)

    Miguel A. Trujano

    2012-10-01

    Full Text Available This work presents a stability analysis and experimental assessment of a visual control algorithm applied to a redundant planar parallel robot under uncertainty in relation to camera orientation. The key feature of the analysis is a strict Lyapunov function that allows the conclusion of asymptotic stability without invoking the Barbashin-Krassovsky-LaSalle invariance theorem. The controller does not rely on velocity measurements and has a structure similar to a classic Proportional Derivative control algorithm. Experiments in a laboratory prototype show that uncertainty in camera orientation does not significantly degrade closed-loop performance.

  11. Parameter Identification and Control Scheme for Monitoring Automatic Thickness Control System with Measurement Delay

    Directory of Open Access Journals (Sweden)

    Xu Yang

    2017-01-01

    Full Text Available The thickness of the steel strip is an important indicator of the overall strip quality. Deviations in thickness are primarily controlled using the automatic gauge control (AGC system of each rolling stand. At the last stand, the monitoring AGC system is usually used, where the deviations in thickness can be directly measured by the X-ray thickness gauge device and used as the input to the AGC system. However, due to the physical distance between the thickness detection device and the rolling stand, time delay is unavoidably present in the thickness control loop, which can affect control performance and lead to system oscillations. Furthermore, the parameters of the system can change due to perturbations from external disturbances. Therefore, this paper proposes an identification and control scheme for monitoring AGC system that can handle time delay and parameter uncertainty. The cross-correlation function is used to estimate the time delay of the system, while the system parameters are identified using a recursive least squares method. The time delay and parameter estimates are then further refined using the Levenberg-Marquardt algorithm, so as to provide the most accurate parameter estimates for the complete system. Simulation results show that, compared with the standard Proportion Integration Differentiation (PID controller approach, the proposed approach is not affected by changes in the time delay and parameter uncertainties.

  12. Robust Control and Motion Planning for Nonlinear Underactuated Systems Using H infinity Techniques

    National Research Council Canada - National Science Library

    Toussaint, Gregory

    2000-01-01

    This thesis presents new techniques for planning and robustly controlling the motion of nonlinear underactuated vehicles when disturbances are present and only imperfect state measurements are available for feedback...

  13. H∞ Robust Control of a Large-Piston MEMS Micromirror for Compact Fourier Transform Spectrometer Systems.

    Science.gov (United States)

    Chen, Huipeng; Li, Mengyuan; Zhang, Yi; Xie, Huikai; Chen, Chang; Peng, Zhangming; Su, Shaohui

    2018-02-08

    Incorporating linear-scanning micro-electro-mechanical systems (MEMS) micromirrors into Fourier transform spectral acquisition systems can greatly reduce the size of the spectrometer equipment, making portable Fourier transform spectrometers (FTS) possible. How to minimize the tilting of the MEMS mirror plate during its large linear scan is a major problem in this application. In this work, an FTS system has been constructed based on a biaxial MEMS micromirror with a large-piston displacement of 180 μm, and a biaxial H∞ robust controller is designed. Compared with open-loop control and proportional-integral-derivative (PID) closed-loop control, H∞ robust control has good stability and robustness. The experimental results show that the stable scanning displacement reaches 110.9 μm under the H∞ robust control, and the tilting angle of the MEMS mirror plate in that full scanning range falls within ±0.0014°. Without control, the FTS system cannot generate meaningful spectra. In contrast, the FTS yields a clean spectrum with a full width at half maximum (FWHM) spectral linewidth of 96 cm -1 under the H∞ robust control. Moreover, the FTS system can maintain good stability and robustness under various driving conditions.

  14. Multivariable robust adaptive sliding mode control of an industrial boiler-turbine in the presence of modeling imprecisions and external disturbances: A comparison with type-I servo controller.

    Science.gov (United States)

    Ghabraei, Soheil; Moradi, Hamed; Vossoughi, Gholamreza

    2015-09-01

    To guarantee the safety and efficient performance of the power plant, a robust controller for the boiler-turbine unit is needed. In this paper, a robust adaptive sliding mode controller (RASMC) is proposed to control a nonlinear multi-input multi-output (MIMO) model of industrial boiler-turbine unit, in the presence of unknown bounded uncertainties and external disturbances. To overcome the coupled nonlinearities and investigate the zero dynamics, input-output linearization is performed, and then the new decoupled inputs are derived. To tackle the uncertainties and external disturbances, appropriate adaption laws are introduced. For constructing the RASMC, suitable sliding surface is considered. To guarantee the sliding motion occurrence, appropriate control laws are constructed. Then the robustness and stability of the proposed RASMC is proved via Lyapunov stability theory. To compare the performance of the purposed RASMC with traditional control schemes, a type-I servo controller is designed. To evaluate the performance of the proposed control schemes, simulation studies on nonlinear MIMO dynamic system in the presence of high frequency bounded uncertainties and external disturbances are conducted and compared. Comparison of the results reveals the superiority of proposed RASMC over the traditional control schemes. RAMSC acts efficiently in disturbance rejection and keeping the system behavior in desirable tracking objectives, without the existence of unstable quasi-periodic solutions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Ofshore Wind Park Control Assessment Methodologies to Assure Robustness

    DEFF Research Database (Denmark)

    Gryning, Mikkel Peter Sidoroff

    in the rather complex control hierarchy on an offshore WPP. The output waveform of modern turbines utilizing PEDs is distorted at high frequencies, and the stability of the control system is affected by resonances and harmonics present in the weak offshore grid. These phenomena pose a risk to drive the system...... with the grid and suggestion of design guidelines to ensure proper operation of stacked controllers. Two specific faults serve as basis for the analysis and development, a rotor blade deformation and an unwanted oscillation in the reactive power, both of which experienced at a WPP. The low frequency reactive...... parameters based on network parameters and the thesis contributes by ensuring proper operation before energization. The analysis of the voltage control philosophy related to the reactive power oscillations showed the need for proper handling of the resonances introduced by the offshore grid in the turbine...

  16. Robust Controller for Turbulent and Convective Boundary Layers

    National Research Council Canada - National Science Library

    Speyer, Jason L; Kim, J. John

    2006-01-01

    Linear feedback controllers and estimators have been designed from the governing equations of a channel flow, linearized about the laminar mean flow, and a layer of heated fluid, linearized about the no-motion state...

  17. Robust Aeroservoelastic Control Utilizing Physics-Based Aerodynamic Sensing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — New aircraft designs depend on an integrated active approach to flight control, flutter suppression and structural mode attenuation to meet desired handling quality...

  18. Robust tracking control for linear vibrating mechanical systems

    Directory of Open Access Journals (Sweden)

    Francisco Beltrán-Carbajal

    2015-01-01

    Full Text Available Se propone un enfoque de control novedoso para seguimiento por realimentación de la salida para sistemas mecánicos vibratorios del tipo masa-resorte-amortiguador lineales sub-actuados. La metodología de diseño de control que se presenta considera robustez con respecto de dinámicas no modeladas y fuerzas externas. El esquema de control propuesto solamente requiere mediciones de la variable de la salida de posición. Se utiliza compensación integral del error de seguimiento de manera apropiada para evitar la estimación en tiempo real de las perturbaciones. Resultado analíticos y numéricos muestran la efectividad del esquema de control activo de vibración para atenuación de vibraciones resonantes y caóticas afectando la respuesta de la variable de salida.

  19. Robust Adaptive Control via Neural Linearization and Compensation

    Directory of Open Access Journals (Sweden)

    Roberto Carmona Rodríguez

    2012-01-01

    Full Text Available We propose a new type of neural adaptive control via dynamic neural networks. For a class of unknown nonlinear systems, a neural identifier-based feedback linearization controller is first used. Dead-zone and projection techniques are applied to assure the stability of neural identification. Then four types of compensator are addressed. The stability of closed-loop system is also proven.

  20. Numerical Nonlinear Robust Control with Applications to Humanoid Robots

    Science.gov (United States)

    2015-07-01

    transcribes a continuous-time optimal control problem directly into an equivalent nonlinear programming problem ( NLP ) [94]. This is done by...established approximate method. The use of collocation in optimal control is a a NLP problem, which can in turn, be converted to a sequential...equivalent condition to the first order KKT conditions of the NLP , which can be solved by a MCP solver such as KNITRO [134]. 4.4 Example - two-dimensional

  1. Design and Implement a Digital H∞ Robust Controller for a MW-Class PMSG-Based Grid-Interactive Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Tomonobu Senjyu

    2013-04-01

    Full Text Available A digital H∞ controller for a permanent magnet synchronous generator (PMSG based wind energy conversion system (WECS is presented. Wind energy is an uncertain fluctuating resource which requires a tight control management. So, it is still an exigent task for the control design engineers. The conventional proportional-integral (PI control is not ideal during high turbulence wind velocities, and the nonlinear behavior of the power converters. These are raising interest towards the robust control concepts. The robust design is to find a controller, for a given system, such that the closed-loop system becomes robust that assurance high-integrity and fault tolerant control system, robust H∞ control theory has befallen a standard design method of choice over the past two decades in industrial control applications. The robust H∞ control theory is also gaining eminence in the WECS. Due to the implementation complexity for the continuous H∞ controller, and availability of the high speedy micro-controllers, the design of a sample-data or a digital H∞ controller is very important for the realistic implementation. But there isn’t a single research to evaluate the performance of the digital H∞ controller for the WECS. In this paper, the proposed digital H∞ controller schemes comprise for the both generator and grid interactive power converters, and the control performances are compared with the conventional PI controller and the fuzzy controller. Simulation results confirm the efficacy of the proposed method Energies 2013, 6 2085 which are ensured the WECS stabilities, mitigate shaft stress, and improving the DC-link voltage and output power qualities.

  2. A unified numerical scheme for linear-quadratic optimal control problems with joint control and state constraints

    NARCIS (Netherlands)

    Han, Lanshan; Camlibel, M. Kanat; Pang, Jong-Shi; Heemels, W. P. Maurice H.

    2012-01-01

    This paper presents a numerical scheme for solving the continuous-time convex linear-quadratic (LQ) optimal control problem with mixed polyhedral state and control constraints. Unifying a discretization of this optimal control problem as often employed in model predictive control and that obtained

  3. PLS-based memory control scheme for enhanced process monitoring

    KAUST Repository

    Harrou, Fouzi

    2017-01-20

    Fault detection is important for safe operation of various modern engineering systems. Partial least square (PLS) has been widely used in monitoring highly correlated process variables. Conventional PLS-based methods, nevertheless, often fail to detect incipient faults. In this paper, we develop new PLS-based monitoring chart, combining PLS with multivariate memory control chart, the multivariate exponentially weighted moving average (MEWMA) monitoring chart. The MEWMA are sensitive to incipient faults in the process mean, which significantly improves the performance of PLS methods and widen their applicability in practice. Using simulated distillation column data, we demonstrate that the proposed PLS-based MEWMA control chart is more effective in detecting incipient fault in the mean of the multivariate process variables, and outperform the conventional PLS-based monitoring charts.

  4. Integrated Backstepping Design of Missile Guidance andControl with Time delay Adaptive Scheme

    Science.gov (United States)

    2016-03-30

    Guidance and Control with Time-delay Adaptive Scheme Seong-Min Hong 1 , Min-Guk Seo 1 , Chang-Hun Lee 2 and Min-Jea Tahk 1 1 Department...engagement kinematics are merged. Control input for the overall system is derived by backstepping approach. The stability of control logic is proved...estimated by using a time-delay adaptive control law. The performance of designed controller is investigated by numerical simulation. Keywords

  5. A homotopy algorithm for synthesizing robust controllers for flexible structures via the maximum entropy design equations

    Science.gov (United States)

    Collins, Emmanuel G., Jr.; Richter, Stephen

    1990-01-01

    One well known deficiency of LQG compensators is that they do not guarantee any measure of robustness. This deficiency is especially highlighted when considering control design for complex systems such as flexible structures. There has thus been a need to generalize LQG theory to incorporate robustness constraints. Here we describe the maximum entropy approach to robust control design for flexible structures, a generalization of LQG theory, pioneered by Hyland, which has proved useful in practice. The design equations consist of a set of coupled Riccati and Lyapunov equations. A homotopy algorithm that is used to solve these design equations is presented.

  6. Transformation of Neural State Space Models into LFT Models for Robust Control Design

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2000-01-01

    This paper considers the extraction of linear state space models and uncertainty models from neural networks trained as state estimators with direct application to robust control. A new method for writing a neural state space model in a linear fractional transformation form in a non-conservative ......-conservative way is proposed, and it is demonstrated how a standard robust control law can be designed for a system described by means of a multi layer perceptron....

  7. A New Robust Controller with Applications to Bioreactors

    Directory of Open Access Journals (Sweden)

    Alejandro Rincón

    2014-01-01

    Full Text Available In this work an anaerobic digester is controlled using input-output linearization and Lyapunov-like function methods. It is assumed that model parameters are unknown, time-varying, and bounded, and upper or lower bounds are also unknown. To tackle the effect of input saturation, a state observer is designed. The tracking and observer errors are defined in terms of the noisy measured output instead of ideal output, given by the mathematical model. The design of the observer mechanism and the update laws is based on the Lyapunov-like function technique, whereas the design of the control law is based on the input-output linearization method. In this paper two important properties of the controlled system are proven. First, the observer error converges asymptotically to a residual set whose size is user-defined, and such convergence is not disrupted, neither by the input saturation nor by the parameter uncertainties. Second, when the control input is nonsaturated the tracking error converges to a residual set whose size is user-defined. The model parameter uncertainties are included to prove the convergence of errors. Finally, a numerical example to validate the developed control is presented.

  8. Performance Comparison of Grid-Faulty Control Schemes for Inverter-Based Industrial Microgrids

    Directory of Open Access Journals (Sweden)

    Antonio Camacho

    2017-12-01

    Full Text Available Several control schemes specifically designed to operate inverter-based industrial microgrids during voltage sags have been recently proposed. This paper first classifies these control schemes in three categories and then performs a comparative analysis of them. Representative control schemes of each category are selected, described and used to identify the main features and performance of the considered category. The comparison is based on the evaluation of several indexes, which measure the power quality of the installation and utility grid during voltage sags, including voltage regulation, reactive current injection and transient response. The paper includes selected simulation results from a 500 kVA industrial microgrid to validate the expected features of the considered control schemes. Finally, in view of the obtained results, the paper proposes an alternative solution to cope with voltage sags, which includes the use of a static compensator in parallel with the microgrid. The novelty of this proposal is the suitable selection of the control schemes for both the microgrid and the static compensator. The superior performance of the proposal is confirmed by the analysis of the quality indexes. Its practical limitations are also revealed, showing that the topic studied in this paper is still open for further research.

  9. Adaptive Test Schemes for Control of Paratuberculosis in Dairy Cows.

    Directory of Open Access Journals (Sweden)

    Carsten Kirkeby

    Full Text Available Paratuberculosis is a chronic infection that in dairy cattle causes reduced milk yield, weight loss, and ultimately fatal diarrhea. Subclinical animals can excrete bacteria (Mycobacterium avium ssp. paratuberculosis, MAP in feces and infect other animals. Farmers identify the infectious animals through a variety of test-strategies, but are challenged by the lack of perfect tests. Frequent testing increases the sensitivity but the costs of testing are a cause of concern for farmers. Here, we used a herd simulation model using milk ELISA tests to evaluate the epidemiological and economic consequences of continuously adapting the sampling interval in response to the estimated true prevalence in the herd. The key results were that the true prevalence was greatly affected by the hygiene level and to some extent by the test-frequency. Furthermore, the choice of prevalence that will be tolerated in a control scenario had a major impact on the true prevalence in the normal hygiene setting, but less so when the hygiene was poor. The net revenue is not greatly affected by the test-strategy, because of the general variation in net revenues between farms. An exception to this is the low hygiene herd, where frequent testing results in lower revenue. When we look at the probability of eradication, then it is correlated with the testing frequency and the target prevalence during the control phase. The probability of eradication is low in the low hygiene herd, and a test-and-cull strategy should probably not be the primary strategy in this herd. Based on this study we suggest that, in order to control MAP, the standard Danish dairy farm should use an adaptive strategy where a short sampling interval of three months is used when the estimated true prevalence is above 1%, and otherwise use a long sampling interval of one year.

  10. Adaptive Test Schemes for Control of Paratuberculosis in Dairy Cows.

    Science.gov (United States)

    Kirkeby, Carsten; Græsbøll, Kaare; Nielsen, Søren Saxmose; Christiansen, Lasse Engbo; Toft, Nils; Halasa, Tariq

    2016-01-01

    Paratuberculosis is a chronic infection that in dairy cattle causes reduced milk yield, weight loss, and ultimately fatal diarrhea. Subclinical animals can excrete bacteria (Mycobacterium avium ssp. paratuberculosis, MAP) in feces and infect other animals. Farmers identify the infectious animals through a variety of test-strategies, but are challenged by the lack of perfect tests. Frequent testing increases the sensitivity but the costs of testing are a cause of concern for farmers. Here, we used a herd simulation model using milk ELISA tests to evaluate the epidemiological and economic consequences of continuously adapting the sampling interval in response to the estimated true prevalence in the herd. The key results were that the true prevalence was greatly affected by the hygiene level and to some extent by the test-frequency. Furthermore, the choice of prevalence that will be tolerated in a control scenario had a major impact on the true prevalence in the normal hygiene setting, but less so when the hygiene was poor. The net revenue is not greatly affected by the test-strategy, because of the general variation in net revenues between farms. An exception to this is the low hygiene herd, where frequent testing results in lower revenue. When we look at the probability of eradication, then it is correlated with the testing frequency and the target prevalence during the control phase. The probability of eradication is low in the low hygiene herd, and a test-and-cull strategy should probably not be the primary strategy in this herd. Based on this study we suggest that, in order to control MAP, the standard Danish dairy farm should use an adaptive strategy where a short sampling interval of three months is used when the estimated true prevalence is above 1%, and otherwise use a long sampling interval of one year.

  11. Adaptive and robust active vibration control methodology and tests

    CERN Document Server

    Landau, Ioan Doré; Castellanos-Silva, Abraham; Constantinescu, Aurelian

    2017-01-01

    This book approaches the design of active vibration control systems from the perspective of today’s ideas of computer control. It formulates the various design problems encountered in the active management of vibration as control problems and searches for the most appropriate tools to solve them. The experimental validation of the solutions proposed on relevant tests benches is also addressed. To promote the widespread acceptance of these techniques, the presentation eliminates unnecessary theoretical developments (which can be found elsewhere) and focuses on algorithms and their use. The solutions proposed cannot be fully understood and creatively exploited without a clear understanding of the basic concepts and methods, so these are considered in depth. The focus is on enhancing motivations, algorithm presentation and experimental evaluation. MATLAB®routines, Simulink® diagrams and bench-test data are available for download and encourage easy assimilation of the experimental and exemplary material. Thre...

  12. HOTELLING'S T2 CONTROL CHARTS BASED ON ROBUST ESTIMATORS

    Directory of Open Access Journals (Sweden)

    SERGIO YÁÑEZ

    2010-01-01

    Full Text Available Under the presence of multivariate outliers, in a Phase I analysis of historical set of data, the T 2 control chart based on the usual sample mean vector and sample variance covariance matrix performs poorly. Several alternative estimators have been proposed. Among them, estimators based on the minimum volume ellipsoid (MVE and the minimum covariance determinant (MCD are powerful in detecting a reasonable number of outliers. In this paper we propose a T 2 control chart using the biweight S estimators for the location and dispersion parameters when monitoring multivariate individual observations. Simulation studies show that this method outperforms the T 2 control chart based on MVE estimators for a small number of observations.

  13. An Approach to Robust Control of the Hopf Bifurcation

    Directory of Open Access Journals (Sweden)

    Giacomo Innocenti

    2011-01-01

    Full Text Available The paper illustrates a novel approach to modify the Hopf bifurcation nature via a nonlinear state feedback control, which leaves the equilibrium properties unchanged. This result is achieved by recurring to linear and nonlinear transformations, which lead the system to locally assume the ordinary differential equation representation. Third-order models are considered, since they can be seen as proper representatives of a larger class of systems. The explicit relationship between the control input and the Hopf bifurcation nature is obtained via a frequency approach, that does not need the computation of the center manifold.

  14. Stability of a neural predictive controller scheme on a neural model

    DEFF Research Database (Denmark)

    Luther, Jim Benjamin; Sørensen, Paul Haase

    2009-01-01

    In previous works presenting various forms of neural-network-based predictive controllers, the main emphasis has been on the implementation aspects, i.e. the development of a robust optimization algorithm for the controller, which will be able to perform in real time. However, the stability issue....... The resulting controller is tested on a nonlinear pneumatic servo system....

  15. Robust chaos synchronization using input-to-state stable control

    Indian Academy of Sciences (India)

    In this paper, we propose a new input-to-state stable (ISS) synchronization method for a general class of chaotic systems with disturbances. Based on Lyapunov theory and linear matrix inequality (LMI) approach, for the first time, the ISS synchronization controller is presented not only to guarantee the asymptotic ...

  16. Robust Regulation and Tracking Control of a Class of Uncertain 2DOF Underactuated Mechanical Systems

    Directory of Open Access Journals (Sweden)

    David I. Rosas Almeida

    2015-01-01

    Full Text Available A strategy to design and implement a robust controller for a class of underactuated mechanical systems, with two degrees of freedom, which solves the problems of regulation and trajectory tracking, is proposed. This control strategy considers the partial measurement of the state vector and the presence of parametric uncertainties in the plant; these conditions are common in the implementation of a control system. The strategy is based on the use of robust finite time convergence observers to estimate the unmeasured state variables, unknown disturbances, and other signals needed for the control system implementation. The performance of the control strategy is illustrated numerically and experimentally.

  17. New scheme of variable optical buffer for IP packets used in access control of HORNET

    Science.gov (United States)

    Fang, Nian; Wang, Lutang; Huang, Zhaoming

    2002-09-01

    A new scheme of variable optical buffer for IP packets is reported. It may be used in access control of HORNET (Hybrid Optoelectronic Ring NETwork), to avoid collision of added packet and the packet already on the ring and improve the loss ratio of the packets. In this scheme, a new multi-wavelength fiber loop memory technique is employed. This architecture uses the wavelength converter (WC) to specify the packets delay and wavelength conversion is accomplished by the technique of four-wave-mixing (FWM) with a semiconductor optical amplifier (SOA). The range of delay is 10 to 9990 bytes periods. First, architecture, operation principle, characteristics and applications of this scheme of variable optical buffer are introduced. Next, a new unslotted CSMA/CA MAC scheme based on the variable optical buffer is briefly introduced too. Finally, the simulation results are presented.

  18. A Novel, Automatic Quality Control Scheme for Real Time Image Transmission

    Directory of Open Access Journals (Sweden)

    S. Ramachandran

    2002-01-01

    Full Text Available A novel scheme to compute energy on-the-fly and thereby control the quality of the image frames dynamically is presented along with its FPGA implementation. This scheme is suitable for incorporation in image compression systems such as video encoders. In this new scheme, processing is automatically stopped when the desired quality is achieved for the image being processed by using a concept called pruning. Pruning also increases the processing speed by a factor of more than two when compared to the conventional method of processing without pruning. An MPEG-2 encoder implemented using this scheme is capable of processing good quality monochrome and color images of sizes up to 1024 × 768 pixels at the rate of 42 and 28 frames per second, respectively, with a compression ratio of over 17:1. The encoder is also capable of working in the fixed pruning level mode with user programmable features.

  19. A circuit scheme to control current surge for RFID-NVM pumps

    Energy Technology Data Exchange (ETDEWEB)

    Li Ming; Kang Jinfeng; Wang Yangyuan [Institute of Microelectronics, Peking University, Beijing 100871 (China); Yang Liwu, E-mail: prettynecess@163.co [Semiconductor Manufacturing International Corporation, Shanghai 201203 (China)

    2010-02-15

    This paper presents a new circuit scheme to control the current surge in the boosting phase of an radio frequency idenfication-nonvolative memory pump. By introducing a circuit block consisting of a current reference and a current mirror, the new circuit scheme can keep the period-average current of the pump constantly below the desired level, for example, 2.5 {mu}A. Therefore, it can prevent the rectified supply of the RFID tag IC from collapsing in the boosting phase of the pump. The presented scheme could effectively reduce the voltage drop on the rectified supply from more than 50% to even zero, but could cost less area. Moreover, an analytical expression to calculate the boosting time of a pump in the new scheme is developed. (semiconductor integrated circuits)

  20. Optimal robust control strategy of a solid oxide fuel cell system

    Science.gov (United States)

    Wu, Xiaojuan; Gao, Danhui

    2018-01-01

    Optimal control can ensure system safe operation with a high efficiency. However, only a few papers discuss optimal control strategies for solid oxide fuel cell (SOFC) systems. Moreover, the existed methods ignore the impact of parameter uncertainty on system instantaneous performance. In real SOFC systems, several parameters may vary with the variation of operation conditions and can not be identified exactly, such as load current. Therefore, a robust optimal control strategy is proposed, which involves three parts: a SOFC model with parameter uncertainty, a robust optimizer and robust controllers. During the model building process, boundaries of the uncertain parameter are extracted based on Monte Carlo algorithm. To achieve the maximum efficiency, a two-space particle swarm optimization approach is employed to obtain optimal operating points, which are used as the set points of the controllers. To ensure the SOFC safe operation, two feed-forward controllers and a higher-order robust sliding mode controller are presented to control fuel utilization ratio, air excess ratio and stack temperature afterwards. The results show the proposed optimal robust control method can maintain the SOFC system safe operation with a maximum efficiency under load and uncertainty variations.

  1. Gráficos de controle X para processos robustos Statistical control of robust processes

    Directory of Open Access Journals (Sweden)

    Antonio Fernando Branco Costa

    1998-12-01

    Full Text Available O avanço tecnológico tem tornado os processos produtivos cada vez mais robustos (robustos no sentido de produzirem itens cada vez mais iguais. Neste contexto, pequenas alterações no processo podem ser críticas, devendo portanto ser eliminadas com rapidez. Tradicionalmente, são utilizados os gráficos das somas acumuladas ou das médias móveis para controlar tais processos. O objetivo deste trabalho é mostrar que os gráficos de Shewhart também podem ser utilizados para controlar processos robustos, bastando variar seus parâmetros de projeto de maneira apropriada.Technological development has reduced the variability between items produced on s large scale. Today, a small change in the process can be critical, requiring rapid action to eliminate it. Traditionally, the CUSUM and the moving mean are the charts used to control these processes that we call robust processes. The aim of this paper is to show that the Shewhart chart can also be used to control robust processes, if the constraint of fixed design parameters is relaxed.

  2. Robustness Enhancement of MRAC Using Modification Techniques for Speed Control of Three Phase Induction Motor

    Directory of Open Access Journals (Sweden)

    Amjad J. Humaidi

    2017-12-01

    Full Text Available This paper addresses the lack of robustness in three phase Induction Motors (I.M speed control in presence of uncertainty and external unknown disturbance of Model Reference Adaptive Control (MRAC, and present an enhancement of robustness by employing the adaptive law modifications for robustness. Considered modifications were Dead zone modification, Sigma modification, e-modification and projection operator algorithm modification. Speed control of three phase induction motor in this paper was depend on decoupling benefits of rotor flux Indirect Field Orientation (IFO. Simulation results shows improved robustness characteristics and performance. In order to make the case study under consideration more realistic, the work considered the limitation imposed on supplied voltage in real application, where this was the other challenge which has been avoided by many researchers.

  3. Robust control decentralized by sliding ways of electrical of power multi-machines systems; Control robusto descentralizado por modos deslizantes de sistemas electricos de potencia multimaquinas

    Energy Technology Data Exchange (ETDEWEB)

    Huerta Avila, Hector

    2008-09-15

    This work deals with the problem of robust decentralized control of multimachine electric power systems. These systems are subject to different perturbations, such as short circuits, connection and/or disconnection of loads, lines generators, mechanical torque variations, etc. Then, it is necessary controllers which guarantee robustness under those perturbations to provide electrical energy to the loads with admissible stability margins. Moreover, the controller must be robust under parametric variations due to model uncertainties, and other physical reasons. The electrical power systems are modeled as complex great scale nonlinear systems. Then, the controller design is a challenging problem. Thus, the decentralized control schemes enable to avoid these problems. This work proposes three novel robust nonlinear techniques. The first one is based on the block control and integral sliding modes. The second obtains a sliding manifold from the Hamiltonian model of a nonlinear system to use this manifold in the integral sliding modes. The third technique enables to apply the sliding mode technique to a nonlinear block controllable system, by using Lyapunov function in each block. Then, four control schemes for electric power systems are designed. The four control schemes are robust under the perturbations of electric power systems mentioned above. The controllers proposed can be implemented in any electric power system with n generators, m lines and k loads. [Spanish] Este trabajo esta dedicado al diseno de esquemas de control robustos descentralizados que sean capaces de responder satisfactoriamente en sistemas electricos de potencia multimaquinas. Estos sistemas estan sujetos a perturbaciones de diferentes tipos, como cortos circuitos, entrada y salida de lineas de cargas o de generadores. Es evidente la necesidad de controladores que puedan rechazar estas perturbaciones para proveer energia de calidad y sin interrupciones a todos los usuarios conectados a la red

  4. Experimental bifurcation analysis of an impact oscillator - Tuning a non-invasive control scheme

    DEFF Research Database (Denmark)

    Bureau, Emil; Schilder, Frank; Santos, Ilmar

    2013-01-01

    We investigate a non-invasive, locally stabilizing control scheme necessary for an experimental bifurcation analysis. Our test-rig comprises a harmonically forced impact oscillator with hardening spring nonlinearity controlled by electromagnetic actuators, and serves as a prototype for electromag...

  5. Lyapunov-Based Control Scheme for Single-Phase Grid-Connected PV Central Inverters

    NARCIS (Netherlands)

    Meza, C.; Biel, D.; Jeltsema, D.; Scherpen, J. M. A.

    A Lyapunov-based control scheme for single-phase single-stage grid-connected photovoltaic central inverters is presented. Besides rendering the closed-loop system globally stable, the designed controller is able to deal with the system uncertainty that depends on the solar irradiance. A laboratory

  6. Robust control for variable-speed two-bladed horizontal-axis wind turbines via chattering control

    OpenAIRE

    Acho Zuppa, Leonardo; Vidal Seguí, Yolanda; Pozo Montero, Francesc

    2009-01-01

    A robust controller with chattering is proposed for variable speed control of a two-bladed horizontal axis wind turbine similar to the DOE MOD-0 model. The chattering term provides robustness against un-modeled non-linearities. To validate the performance of the proposed controller, a dynamic wind model has also been developed. This model is based on using an harmonic oscillator with an additive white noise to capture some stochastic behavior of the wind perturbation.

  7. Robust Bio-Signal Based Control of an Intelligent Wheelchair

    Directory of Open Access Journals (Sweden)

    Dongyi Chen

    2013-09-01

    Full Text Available In this paper, an adaptive human-machine interaction (HMI method that is based on surface electromyography (sEMG signals is proposed for the hands-free control of an intelligent wheelchair. sEMG signals generated by the facial movements are obtained by a convenient dry electrodes sensing device. After the signals features are extracted from the autoregressive model, control data samples are updated and trained by an incremental online learning algorithm in real-time. Experimental results show that the proposed method can significantly improve the classification accuracy and training speed. Moreover, this method can effectively reduce the influence of muscle fatigue during a long time operation of sEMG-based HMI.

  8. Robust Nonlinear Control Based on Disturbance Observer for a Small-Scale Unmanned Helicopter

    Directory of Open Access Journals (Sweden)

    Amir Razzaghian

    2017-09-01

    Full Text Available A robust nonlinear controller based on disturbance observer for the trajectory tracking control of a small-scale unmanned helicopter with nonlinear structure under external disturbances and parameter uncertainties is designed. The control objective is to let the helicopter track a predefined trajectory. The proposed robust nonlinear controller is based on the backstepping sliding mode control technique which combines both the capabilities of backstepping control and sliding mode control. The control performance developed based on a time-varying disturbance observer. In order to obtain an efficient control law design, the nonlinear model of the helicopter is reformulated as an affine nonlinear system. The mathematical proof using Lyapunov stability theorem shows that the closed loop system is asymptotically stable in the presence of this controller. To verify the robustness and stability of the proposed controller, it is compared with conventional sliding mode controller. The chattering phenomenon is attenuated significantly and the tracking error is also alleviated. The simulation results confirm the desirable performance of proposed robust nonlinear controller.

  9. Optimization of a Traffic Control Scheme for a Post-Disaster Urban Road Network

    Directory of Open Access Journals (Sweden)

    Zengzhen Shao

    2017-12-01

    Full Text Available Traffic control of urban road networks during emergency rescues is conducive to rapid rescue in the affected areas. However, excessive control will lead to negative impacts on the normal traffic order. We propose a novel model to optimize the traffic control scheme during the post-disaster emergency rescue period named PD-TCM (post-disaster traffic control model. In this model, the vertex and edge betweenness indexes of urban road networks are introduced to evaluate the controllability of the road sections. The gravity field model is also used to adjust the travel time function of different road sections in the control and diverging domains. Experimental results demonstrate that the proposed model can obtain the optimal traffic control scheme efficiently, which gives it the ability to meet the demand of emergency rescues as well as reducing the disturbances caused by controls.

  10. Robust Active Disturbance Rejection Control Approach to Maximize Energy Capture in Variable-Speed Wind Turbines

    Directory of Open Access Journals (Sweden)

    Horacio Coral-Enriquez

    2013-01-01

    Full Text Available This paper proposes an alternative robust observer-based linear control technique to maximize energy capture in a 4.8 MW horizontal-axis variable-speed wind turbine. The proposed strategy uses a generalized proportional integral (GPI observer to reconstruct the aerodynamic torque in order to obtain a generator speed optimal trajectory. Then, a robust GPI observer-based controller supported by an active disturbance rejection (ADR approach allows asymptotic tracking of the generator speed optimal trajectory. The proposed methodology controls the power coefficient, via the generator angular speed, towards an optimum point at which power coefficient is maximum. Several simulations (including an actuator fault are performed on a 4.8 MW wind turbine benchmark model in order to validate the proposed control strategy and to compare it to a classical controller. Simulation and validation results show that the proposed control strategy is effective in terms of power capture and robustness.

  11. Multi-input robust saturation controller for uncertain linear time-invariant systems

    Science.gov (United States)

    Lim, Chae-Wook

    2007-03-01

    A robust saturation controller for the linear time-invariant (LTI) system involving both a control input's saturation and structured real parameter uncertainties was proposed in [C.W. Lim, Y. J. Park, S.J. Moon, Robust saturation controller for linear time-invariant system with structured real parameter uncertainties, Journal of Sound and Vibration 294 (1-2) (2006) 1-14]. This controller can also be applicable to the multi-input case. In this paper, the robust saturation controller is extended to the uncertain LTI system with multi-input and designed by introducing additional subsidiary setting parameters for each control input. An example is presented to show its application to multi-input uncertain LTI systems.

  12. Adaptive Fuzzy Robust Control for a Class of Nonlinear Systems via Small Gain Theorem

    Directory of Open Access Journals (Sweden)

    Xingjian Wang

    2013-01-01

    Full Text Available Practical nonlinear systems can usually be represented by partly linearizable models with unknown nonlinearities and external disturbances. Based on this consideration, we propose a novel adaptive fuzzy robust control (AFRC algorithm for such systems. The AFRC effectively combines techniques of adaptive control and fuzzy control, and it improves the performance by retaining the advantages of both methods. The linearizable part will be linearly parameterized with unknown but constant parameters, and the discontinuous-projection-based adaptive control law is used to compensate these parts. The Takagi-Sugeno fuzzy logic systems are used to approximate unknown nonlinearities. Robust control law ensures the robustness of closed-loop control system. A systematic design procedure of the AFRC algorithm by combining the backstepping technique and small-gain approach is presented. Then the closed-loop stability is studied by using small gain theorem, and the result indicates that the closed-loop system is semiglobally uniformly ultimately bounded.

  13. Autonomous Distributed Congestion Control Scheme in WCDMA Network

    Science.gov (United States)

    Ahmad, Hafiz Farooq; Suguri, Hiroki; Choudhary, Muhammad Qaisar; Hassan, Ammar; Liaqat, Ali; Khan, Muhammad Umer

    Wireless technology has become widely popular and an important means of communication. A key issue in delivering wireless services is the problem of congestion which has an adverse impact on the Quality of Service (QoS), especially timeliness. Although a lot of work has been done in the context of RRM (Radio Resource Management), the deliverance of quality service to the end user still remains a challenge. Therefore there is need for a system that provides real-time services to the users through high assurance. We propose an intelligent agent-based approach to guarantee a predefined Service Level Agreement (SLA) with heterogeneous user requirements for appropriate bandwidth allocation in QoS sensitive cellular networks. The proposed system architecture exploits Case Based Reasoning (CBR) technique to handle RRM process of congestion management. The system accomplishes predefined SLA through the use of Retrieval and Adaptation Algorithm based on CBR case library. The proposed intelligent agent architecture gives autonomy to Radio Network Controller (RNC) or Base Station (BS) in accepting, rejecting or buffering a connection request to manage system bandwidth. Instead of simply blocking the connection request as congestion hits the system, different buffering durations are allocated to diverse classes of users based on their SLA. This increases the opportunity of connection establishment and reduces the call blocking rate extensively in changing environment. We carry out simulation of the proposed system that verifies efficient performance for congestion handling. The results also show built-in dynamism of our system to cater for variety of SLA requirements.

  14. A robust adaptive load frequency control for micro-grids

    DEFF Research Database (Denmark)

    Khooban, Mohammad-Hassan; Niknam, Taher; Blaabjerg, Frede

    2016-01-01

    micro-grid (MG) is introduced that can consider electric vehicles׳ (EV(s)) effect. Moreover, in this paper, a new combination of the General Type II Fuzzy Logic Sets (GT2FLS) and the Modified Harmony Search Algorithm (MHSA) technique is applied for adaptive tuning of proportional-integral (PI......) controller. Implementing General Type II Fuzzy Systems is computationally expensive. However, using a recently introduced α-plane representation, GT2FLS can be seen as a composition of several Interval Type II Fuzzy Logic Systems (IT2FLS) with a corresponding level of α for each. Real-data from an offshore...

  15. Parameter Space Techniques for Robust Control System Design.

    Science.gov (United States)

    1980-07-01

    JSEP-NO0014- 79-C-0424 Juergen Ackermann, S. Norman Franklin, Christine FS-78-3633 AFOSR-78-3633 B. Chato, and Douglas P. Looze 9. PERFORMING...Ackermann, S. Norman Franklin, Christine B. Chato, and Douglas P. Looze P DThis work was supported in part by the Joint Services Electronics Program (U.S...example of a crane. In Chapter 5, it will be used to design a dynamic controller for the short period longitudinal mode of an F4-E aircraft with canards

  16. Robust, Gain-Scheduled Control of Wind Turbines

    DEFF Research Database (Denmark)

    Østergaard, Kasper Zinck

    Wind turbines are today large and efficient machines, which are combined into wind farms operating on par with conventional power plants. When looking back, this is significantly different from the status only a few years ago, when wind turbines were sold mainly to private people. This change...... in turbine owners has resulted in a new focus on operational reliability instead of turbine size. This research deals with investigating model-based gain-scheduling control of wind turbines by use of linear parameter varying (LPV) methods. The numerical challenges grow quickly with the model size...

  17. HYBRID SYSTEM BASED FUZZY-PID CONTROL SCHEMES FOR UNPREDICTABLE PROCESS

    Directory of Open Access Journals (Sweden)

    M.K. Tan

    2011-07-01

    Full Text Available In general, the primary aim of polymerization industry is to enhance the process operation in order to obtain high quality and purity product. However, a sudden and large amount of heat will be released rapidly during the mixing process of two reactants, i.e. phenol and formalin due to its exothermic behavior. The unpredictable heat will cause deviation of process temperature and hence affect the quality of the product. Therefore, it is vital to control the process temperature during the polymerization. In the modern industry, fuzzy logic is commonly used to auto-tune PID controller to control the process temperature. However, this method needs an experienced operator to fine tune the fuzzy membership function and universe of discourse via trial and error approach. Hence, the setting of fuzzy inference system might not be accurate due to the human errors. Besides that, control of the process can be challenging due to the rapid changes in the plant parameters which will increase the process complexity. This paper proposes an optimization scheme using hybrid of Q-learning (QL and genetic algorithm (GA to optimize the fuzzy membership function in order to allow the conventional fuzzy-PID controller to control the process temperature more effectively. The performances of the proposed optimization scheme are compared with the existing fuzzy-PID scheme. The results show that the proposed optimization scheme is able to control the process temperature more effectively even if disturbance is introduced.

  18. Robust trajectory tracking control of a dual-arm space robot actuated by control moment gyroscopes

    Science.gov (United States)

    Jia, Yinghong; Misra, Arun K.

    2017-08-01

    It is a new design concept to employ control moment gyroscopes (CMGs) as reactionless actuators for space robots. Such actuation has several noticeable advantages such as weak dynamical coupling and low power consumption over traditional joint motor actuation. This paper presents a robust control law for a CMG-actuated space robot in presence of system uncertainties and closed-chain constraints. The control objective is to make the manipulation variables to track the desired trajectories, and reduce the possibility of CMG saturation simultaneously. A reduced-order dynamical equation in terms of independent motion variables is derived using Kane's equations. Desired trajectories of the independent motion variables are derived by minimum-norm trajectory planning algorithm, and an adaptive sliding mode controller with improved adaptation laws is proposed to drive the independent motion variables tracking the desired trajectories. Uniformly ultimate boundedness of the closed loop system is proven using Lyapunov method. The redundancy of the full-order actual control torques is utilized to generate a null torque vector which reduces the possibility of CMG angular momentum saturation while producing no effect on the reduced-order control input. Simulation results demonstrate the effectiveness of the proposed algorithms and the advantage of weak dynamical coupling of the CMG-actuated system.

  19. Robust and Fault-Tolerant Linear Parameter-Varying Control of Wind Turbines

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Esbensen, Thomas; Stoustrup, Jakob

    2011-01-01

    a robust controller (RC). This controller is able to take into account model uncertainties in the aerodynamic model. The controllers are based on output feedback and are scheduled on an estimated wind speed to manage the parameter-varying nature of the model. Furthermore, the AFTC relies on information...

  20. Physical control oriented model of large scale refrigerators to synthesize advanced control schemes. Design, validation, and first control results

    Science.gov (United States)

    Bonne, François; Alamir, Mazen; Bonnay, Patrick

    2014-01-01

    In this paper, a physical method to obtain control-oriented dynamical models of large scale cryogenic refrigerators is proposed, in order to synthesize model-based advanced control schemes. These schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in the cryogenic cooling systems of future fusion reactors such as the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT-60SA). Advanced control schemes lead to a better perturbation immunity and rejection, to offer a safer utilization of cryoplants. The paper gives details on how basic components used in the field of large scale helium refrigeration (especially those present on the 400W @1.8K helium test facility at CEA-Grenoble) are modeled and assembled to obtain the complete dynamic description of controllable subsystems of the refrigerator (controllable subsystems are namely the Joule-Thompson Cycle, the Brayton Cycle, the Liquid Nitrogen Precooling Unit and the Warm Compression Station). The complete 400W @1.8K (in the 400W @4.4K configuration) helium test facility model is then validated against experimental data and the optimal control of both the Joule-Thompson valve and the turbine valve is proposed, to stabilize the plant under highly variable thermals loads. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.

  1. An improved current control scheme for grid-connected DG unit based distribution system harmonic compensation

    DEFF Research Database (Denmark)

    He, Jinwei; Wei Li, Yun; Wang, Xiongfei

    2013-01-01

    In order to utilize DG unit interfacing converters to actively compensate distribution system harmonics, this paper proposes an enhanced current control approach. It seamlessly integrates system harmonic mitigation capabilities with the primary DG power generation function. As the proposed current...... controller has two well decoupled control branches to independently control fundamental and harmonic DG currents, phase-locked loops (PLL) and system harmonic component extractions can be avoided during system harmonic compensation. Moreover, a closed-loop power control scheme is also employed to derive...... the fundamental current reference. The proposed power control scheme effectively eliminates the impacts of steady-state fundamental current tracking errors in the DG units. Thus, an accurate power control is realized even when the harmonic compensation functions are activated. Experimental results from a single...

  2. A COMPARISON OF SOME ROBUST BIVARIATE CONTROL CHARTS FOR INDIVIDUAL OBSERVATIONS

    Directory of Open Access Journals (Sweden)

    Moustafa Omar Ahmed Abu - Shawiesh

    2014-06-01

    Full Text Available This paper proposed and considered some bivariate control charts to monitor individual observations from a statistical process control. Usual control charts which use mean and variance-covariance estimators are sensitive to outliers. We consider the following robust alternatives to the classical Hoteling's T2: T2MedMAD, T2MCD, T2MVE a simulation study has been conducted to compare the performance of these control charts. Two real life data are analyzed to illustrate the application of these robust alternatives.

  3. Improving accuracy in astrocytomas grading by integrating a robust least squares mapping driven support vector machine classifier into a two level grade classification scheme.

    Science.gov (United States)

    Glotsos, Dimitris; Kalatzis, Ioannis; Spyridonos, Panagiota; Kostopoulos, Spiros; Daskalakis, Antonis; Athanasiadis, Emmanouil; Ravazoula, Panagiota; Nikiforidis, George; Cavouras, Dionisis

    2008-06-01

    Grading of astrocytomas is an important task for treatment planning; however, it suffers from significantly great inter-observer variability. Computer-assisted diagnosis systems have been propose to assist towards minimizing subjectivity, however, these systems present either moderate accuracy or utilize specialized staining protocols and grading systems that are difficult to apply in daily clinical practice. The present study proposes a robust mathematical formulation by integrating state-of-art technologies (support vector machines and least squares mapping) in a cascade classification scheme for separating low from high and grade III from grade IV astrocytic tumours. Results have indicated that low from high-grade tumours can be correctly separated with a certainty as high as 97.3%, whereas grade III from grade IV tumours with 97.8%. The overall performance was 95.2%. These high rates have been a result of applying the least squares mapping technique to features prior to classification. A significant byproduct of least squares mapping is that the number of support vectors of the SVM classifiers dropped dramatically from about 80% when no mapping was used to less than 5% when mapping was used. The latter is a clear indication that the SVM classifier has a greater potential to generalize well to new data. In this way, digital image analysis systems for automated grading of astrocytomas are brought closer to clinical practice.

  4. Robust extrapolation scheme for fast estimation of 3D Ising field partition functions: application to within subject fMRI data

    Energy Technology Data Exchange (ETDEWEB)

    Risser, L.; Vincent, T.; Ciuciu, Ph. [NeuroSpin CEA, F-91191 Gif sur Yvette (France); Risser, L.; Vincent, T. [Laboratoire de Neuroimagerie Assistee par Ordinateur (LNAO) CEA - DSV/I2BM/NEUROSPIN (France); Risser, L. [Institut de mecanique des fluides de Toulouse (IMFT), CNRS: UMR5502 - Universite Paul Sabatier - Toulouse III - Institut National Polytechnique de Toulouse - INPT (France); Idier, J. [Institut de Recherche en Communications et en Cybernetique de Nantes (IRCCyN) CNRS - UMR6597 - Universite de Nantes - ecole Centrale de Nantes - Ecole des Mines de Nantes - Ecole Polytechnique de l' Universite de Nantes (France)

    2009-07-01

    In this paper, we present a first numerical scheme to estimate Partition Functions (PF) of 3D Ising fields. Our strategy is applied to the context of the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated regions and estimate region-dependent, hemodynamic filters. For any region, a specific binary Markov random field may embody spatial correlation over the hidden states of the voxels by modeling whether they are activated or not. To make this spatial regularization fully adaptive, our approach is first based upon it, classical path-sampling method to approximate a small subset of reference PFs corresponding to pre-specified regions. Then, file proposed extrapolation method allows its to approximate the PFs associated with the Ising fields defined over the remaining brain regions. In comparison with preexisting approaches, our method is robust; to topological inhomogeneities in the definition of the reference regions. As a result, it strongly alleviates the computational burden and makes spatially adaptive regularization of whole brain fMRI datasets feasible. (authors)

  5. Synthesis of Model Based Robust Stabilizing Reactor Power Controller for Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    Arshad Habib Malik

    2011-04-01

    Full Text Available In this paper, a nominal SISO (Single Input Single Output model of PHWR (Pressurized Heavy Water Reactor type nuclear power plant is developed based on normal moderator pump-up rate capturing the moderator level dynamics using system identification technique. As the plant model is not exact, therefore additive and multiplicative uncertainty modeling is required. A robust perturbed plant model is derived based on worst case model capturing slowest moderator pump-up rate dynamics and moderator control valve opening delay. Both nominal and worst case models of PHWR-type nuclear power plant have ARX (An Autoregressive Exogenous structures and the parameters of both models are estimated using recursive LMS (Least Mean Square optimization algorithm. Nominal and worst case discrete plant models are transformed into frequency domain for robust controller design purpose. The closed loop system is configured into two port model form and H? robust controller is synthesized. The H?controller is designed based on singular value loop shaping and desired magnitude of control input. The selection of desired disturbance attenuation factor and size of the largest anticipated multiplicative plant perturbation for loop shaping of H? robust controller form a constrained multi-objective optimization problem. The performance and robustness of the proposed controller is tested under transient condition of a nuclear power plant in Pakistan and found satisfactory.

  6. Observer-Based Robust Controller Design for Nonlinear Fractional-Order Uncertain Systems via LMI

    Directory of Open Access Journals (Sweden)

    Jing Qiu

    2017-01-01

    Full Text Available We discuss the observer-based robust controller design problem for a class of nonlinear fractional-order uncertain systems with admissible time-variant uncertainty in the case of the fractional-order satisfying 0<α<1. Based on direct Lyapunov approach, a sufficient condition for the robust asymptotic stability of the observer-based nonlinear fractional-order uncertain systems is presented. Employing Finsler’s Lemma, the systematic robust stabilization design algorithm is then proposed in terms of linear matrix inequalities (LMIs. The efficiency and advantage of the proposed algorithm are finally illustrated by two numerical simulations.

  7. Second Order Sliding Mode Control Scheme for an Autonomous Underwater Vehicle with Dynamic Region Concept

    Directory of Open Access Journals (Sweden)

    Zool H. Ismail

    2015-01-01

    Full Text Available The main goal in developing closed loop control system for an Autonomous Underwater Vehicle (AUV is to make a robust vehicle from natural and exogenous perturbations such as wind, wave, and ocean currents. However a well-known robust control, for instance, Sliding Mode Controller (SMC, gives a chattering effect and it influences the stability of an AUV. Furthermore, some researchers combined other controls to get better result but it tends to present long computational time and causes large energy consumption. Thus, this paper proposed a Super Twisting Sliding Mode Controller (STSMC with dynamic region concept for an AUV. STSMC or a second order SMC is adopted as a robust controller which is free from chattering effect. Meanwhile, the implementation of dynamic region is useful to reduce the energy usage. As a result, the proposed controller obtains global asymptotic stability which is validated by using Lyapunov-like function. Moreover, some simulations present the efficiency of proposed controller. In conclusion, STSMC with region based control is effective to be applied for the robust tracking of an AUV. It contributes to give a fast response when handling the perturbations, short computational time, and low energy demand.

  8. Decoupling and Robust Adaptive Control of Omnidirectional, Automated Guided Vehicle Based on Nonguided Line Navigation System

    OpenAIRE

    Kawasaki, Yoshinori; Iwai, Zenta; Haramaki, Shinya; カワサキ, ヨシノリ; イワイ, ゼンタ; ハラマキ, シンヤ; 川崎, 義則; 岩井, 善太; 原槙, 真也

    1994-01-01

    This paper is concerned with a control system design for the new type of omnidirectional AGV (automated guided vehicle) without any steering mechanisms. The system is regarded as a highly nonlinear multidimensional system with parameter uncertainties, so the conventional control techniques are not available. Here we propose a new control algorithm by combining nonlinear decoupling control with robust simple adaptive control (SAC). Both techniques were developed by one of the authors. The cont...

  9. Design of a H∞ Robust Controller with μ-Analysis for Steam Turbine Power Generation Applications

    Directory of Open Access Journals (Sweden)

    Vincenzo Iannino

    2017-07-01

    Full Text Available Concentrated Solar Power plants are complex systems subjected to quite sensitive variations of the steam production profile and external disturbances, thus advanced control techniques that ensure system stability and suitable performance criteria are required. In this work, a multi-objective H∞ robust controller is designed and applied to the power control of a Concentered Solar Power plant composed by two turbines, a gear and a generator. In order to provide robust performance and stability in presence of disturbances, not modeled plant dynamics and plant-parameter variations, the advanced features of the μ-analysis are exploited. A high order controller is obtained from the process of synthesis that makes the implementation of the controller difficult and computational more demanding for a Programmable Logic Controller. Therefore, the controller order is reduced through the Balanced Truncation method and then discretized. The obtained robust control is compared to the current Proportional Integral Derivative-based governing system in order to evaluate its performance, considering unperturbed as well as perturbed scenarios, taking into account variations of steam conditions, sensor measurement delays and power losses. The simulations results show that the proposed controller achieves better robustness and performance compared to the existing Proportional Integral Derivative controller.

  10. A New Pricing Scheme for Controlling Energy Storage Devices in Future Smart Grid

    Directory of Open Access Journals (Sweden)

    Jingwei Zhu

    2014-01-01

    Full Text Available Improvement of the overall efficiency of energy infrastructure is one of the main anticipated benefits of the deployment of smart grid technology. Advancement in energy storage technology and two-way communication in the electric network are indispensable components to achieve such a vision, while efficient pricing schemes and appropriate storage management are also essential. In this paper, we propose a universal pricing scheme which permits one to indirectly control the energy storage devices in the grid to achieve a more desirable aggregate demand profile that meets a particular target of the grid operator such as energy generation cost minimization and carbon emission reduction. Such a pricing scheme can potentially be applied to control the behavior of energy storage devices installed for integration of intermittent renewable energy sources that have permission to grid connection and will have broader applications as an increasing number of novel and low-cost energy storage technologies emerge.

  11. An effective and secure key-management scheme for hierarchical access control in E-medicine system.

    Science.gov (United States)

    Odelu, Vanga; Das, Ashok Kumar; Goswami, Adrijit

    2013-04-01

    Recently several hierarchical access control schemes are proposed in the literature to provide security of e-medicine systems. However, most of them are either insecure against 'man-in-the-middle attack' or they require high storage and computational overheads. Wu and Chen proposed a key management method to solve dynamic access control problems in a user hierarchy based on hybrid cryptosystem. Though their scheme improves computational efficiency over Nikooghadam et al.'s approach, it suffers from large storage space for public parameters in public domain and computational inefficiency due to costly elliptic curve point multiplication. Recently, Nikooghadam and Zakerolhosseini showed that Wu-Chen's scheme is vulnerable to man-in-the-middle attack. In order to remedy this security weakness in Wu-Chen's scheme, they proposed a secure scheme which is again based on ECC (elliptic curve cryptography) and efficient one-way hash function. However, their scheme incurs huge computational cost for providing verification of public information in the public domain as their scheme uses ECC digital signature which is costly when compared to symmetric-key cryptosystem. In this paper, we propose an effective access control scheme in user hierarchy which is only based on symmetric-key cryptosystem and efficient one-way hash function. We show that our scheme reduces significantly the storage space for both public and private domains, and computational complexity when compared to Wu-Chen's scheme, Nikooghadam-Zakerolhosseini's scheme, and other related schemes. Through the informal and formal security analysis, we further show that our scheme is secure against different attacks and also man-in-the-middle attack. Moreover, dynamic access control problems in our scheme are also solved efficiently compared to other related schemes, making our scheme is much suitable for practical applications of e-medicine systems.

  12. A robust H∞ control-based hierarchical mode transition control system for plug-in hybrid electric vehicle

    Science.gov (United States)

    Yang, Chao; Jiao, Xiaohong; Li, Liang; Zhang, Yuanbo; Chen, Zheng

    2018-01-01

    To realize a fast and smooth operating mode transition process from electric driving mode to engine-on driving mode, this paper presents a novel robust hierarchical mode transition control method for a plug-in hybrid electric bus (PHEB) with pre-transmission parallel hybrid powertrain. Firstly, the mode transition process is divided into five stages to clearly describe the powertrain dynamics. Based on the dynamics models of powertrain and clutch actuating mechanism, a hierarchical control structure including two robust H∞ controllers in both upper layer and lower layer is proposed. In upper layer, the demand clutch torque can be calculated by a robust H∞controller considering the clutch engaging time and the vehicle jerk. While in lower layer a robust tracking controller with L2-gain is designed to perform the accurate position tracking control, especially when the parameters uncertainties and external disturbance occur in the clutch actuating mechanism. Simulation and hardware-in-the-loop (HIL) test are carried out in a traditional driving condition of PHEB. Results show that the proposed hierarchical control approach can obtain the good control performance: mode transition time is greatly reduced with the acceptable jerk. Meanwhile, the designed control system shows the obvious robustness with the uncertain parameters and disturbance. Therefore, the proposed approach may offer a theoretical reference for the actual vehicle controller.

  13. Optimal strategy analysis based on robust predictive control for inventory system with random demand

    Science.gov (United States)

    Saputra, Aditya; Widowati, Sutrisno

    2017-12-01

    In this paper, the optimal strategy for a single product single supplier inventory system with random demand is analyzed by using robust predictive control with additive random parameter. We formulate the dynamical system of this system as a linear state space with additive random parameter. To determine and analyze the optimal strategy for the given inventory system, we use robust predictive control approach which gives the optimal strategy i.e. the optimal product volume that should be purchased from the supplier for each time period so that the expected cost is minimal. A numerical simulation is performed with some generated random inventory data. We simulate in MATLAB software where the inventory level must be controlled as close as possible to a set point decided by us. From the results, robust predictive control model provides the optimal strategy i.e. the optimal product volume that should be purchased and the inventory level was followed the given set point.

  14. Robust Stability of Fractional Order Time-Delay Control Systems: A Graphical Approach

    Directory of Open Access Journals (Sweden)

    Radek Matušů

    2015-01-01

    Full Text Available The paper deals with a graphical approach to investigation of robust stability for a feedback control loop with an uncertain fractional order time-delay plant and integer order or fractional order controller. Robust stability analysis is based on plotting the value sets for a suitable range of frequencies and subsequent verification of the zero exclusion condition fulfillment. The computational examples present the typical shapes of the value sets of a family of closed-loop characteristic quasipolynomials for a fractional order plant with uncertain gain, time constant, or time-delay term, respectively, and also for combined cases. Moreover, the practically oriented example focused on robust stability analysis of main irrigation canal pool controlled by either classical integer order PID or fractional order PI controller is included as well.

  15. Adaptive Robust Control for Space Robot with Ucertainty base on Neural Network

    Directory of Open Access Journals (Sweden)

    Zhang Wenhui

    2013-11-01

    Full Text Available The trajectory tracking problems of a class of space robot manipulators with parameters and non-parameters uncertainty are considered. An adaptive robust control algorithm based on neural network is proposed by the paper. Neutral network is used to adaptive learn and compensate the unknown system for parameters uncertainties? the weight adaptive laws are designed by the paper? System stability base on Lyapunov theory is analysised to ensure the convergence of the algorithm. Non-parameters uncertainties are estimated and compensated by robust controller. It is proven that the designed controller can guarantee the asymptotic convergence of tracking error. The controller could guarantee good robust and the stability of closed-loop system. The simulation results show that the presented method is effective.

  16. Robust H∞ output feedback control of bidirectional inductive power transfer systems

    Directory of Open Access Journals (Sweden)

    Swain Akshya

    2017-03-01

    Full Text Available Bidirectional Inductive power transfer (IPT systems behave as high order resonant networks and hence are highly sensitive to changes in system parameters. Traditional PID controllers often fail to maintain satisfactory power regulation in the presence of parametric uncertainties. To overcome these problems, this paper proposes a robust controller which is designed using linear matrix inequality (LMI techniques. The output sensitivity to parametric uncertainty is explored and a linear fractional transformation of the nominal model and its uncertainty is discussed to generate a standard configuration for μ-synthesis and LMI analysis. An H∞ controller is designed based on the structured singular value and LMI feasibility analysis with regard to uncertainties in the primary tuning capacitance, the primary and pickup inductors and the mutual inductance. Robust stability and robust performance of the system is studied through μ-synthesis and LMI feasibility analysis. Simulations and experiments are conducted to verify the power regulation performance of the proposed controller.

  17. Attitude Analysis and Robust Adaptive Backstepping Sliding Mode Control of Spacecrafts Orbiting Irregular Asteroids

    Directory of Open Access Journals (Sweden)

    Chunhui Liang

    2014-01-01

    Full Text Available Attitude stability analysis and robust control algorithms for spacecrafts orbiting irregular asteroids are investigated in the presence of model uncertainties and external disturbances. Rigid spacecraft nonlinear attitude models are considered and detailed attitude stability analysis of spacecraft subjected to the gravity gradient torque in an irregular central gravity field is included in retrograde orbits and direct orbits using linearized system model. The robust adaptive backstepping sliding mode control laws are designed to make the attitude of the spacecrafts stabilized and responded accurately to the expectation in the presence of disturbances and parametric uncertainties. Numerical simulations are included to illustrate the spacecraft performance obtained using the proposed control laws.

  18. Robust Quasi-LPV Control Based on Neural State Space Models

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2002-01-01

    In this paper we derive a synthesis result for robust LPV output feedback controllers for nonlinear systems modelled by neural state space models. This result is achieved by writing the neural state space model on a linear fractional transformation form in a non-conservative way, separating...... that there is some uncertainty on the identified nonlinearities. The control law is therefore made robust to noise perturbations. After formulating the controller synthesis as a set of LMIs with added constraints, some implementation issues are addressed and a simulation example is presented....

  19. Robust H-infinity control synthesis method and its application to benchmark problems

    Science.gov (United States)

    Wie, Bong; Liu, Qiang; Byun, Kuk-Whan

    1992-01-01

    This paper presents a robust H-infinity control synthesis method for structured parameter uncertainty. The robust H-infinity control design methodology is also incorporated with the so-called internal model principle for persistent-disturbance rejection. A noncollocated control problem of flexible space structures subject to parameter variations is used to illustrate the design methodology. It is shown that the proposed design method invariably makes use of nonminimum-phase compensation and that it achieves the desired asymptotic disturbance rejection by having a disturbance rejection 'dipole'.

  20. Design of Nonlinear Robust Rotor Current Controller for DFIG Based on Terminal Sliding Mode Control and Extended State Observer

    Directory of Open Access Journals (Sweden)

    Guowei Cai

    2014-01-01

    Full Text Available As to strong nonlinearity of doubly fed induction generators (DFIG and uncertainty of its model, a novel rotor current controller with nonlinearity and robustness is proposed to enhance fault ride-though (FRT capacities of grid-connected DFIG. Firstly, the model error, external disturbances, and the uncertain factors were estimated by constructing extended state observer (ESO so as to achieve linearization model, which is compensated dynamically from nonlinear model. And then rotor current controller of DFIG is designed by using terminal sliding mode variable structure control theory (TSMC. The controller has superior dynamic performance and strong robustness. The simulation results show that the proposed control approach is effective.

  1. Robust Multivariable Feedback Control of Natural Gas-Diesel RCCI Combustion

    NARCIS (Netherlands)

    Indrajuana, A.; Bekdemir, C.; Luo, X.; Willems, F.P.T.

    2016-01-01

    Advanced combustion concepts such as Reactivity Controlled Compression Ignition (RCCI) demonstrate very high thermal efficiencies combined with ultra low NOx emissions. As RCCI is sensitive for operating conditions, closed-loop control is a crucial enabler for stable and robust combustion. The

  2. Wind turbine inverter robust loop-shaping control subject to grid interaction effects

    DEFF Research Database (Denmark)

    Gryning, Mikkel Peter Sidoroff; Wu, Qiuwei; Blanke, Mogens

    2015-01-01

    with integral effect while bounding the induced change. The design was tested in an aggregated model of the London Array offshore wind power plant and compared with traditional PI controller designs. Robust stability and performance and a reduction of control effort by 25% are obtained over the full envelope...

  3. Robust Adaptive Backstepping Control Design for a Nonlinear Hydraulic-Mechanical System

    DEFF Research Database (Denmark)

    Choux, Martin; Karimi, Hamid Reza; Hovland, Geir

    2009-01-01

    The complex dynamics that characterize hydraulic systems make it difficult for the control design to achieve prescribed goals in an efficient manner. In this paper, we present the design and analysis of a robust nonlinear controller for a nonlinear hydraulic-mechanical (NHM) system. The system co...

  4. Robust reconfigurable control for parametric and additive faults with FDI uncertainties

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Yang, Zhenyu

    2000-01-01

    From the system recoverable point of view, this paper discusses robust reconfigurable control synthesis for LTI systems and a class of nonlinear control systems with parametric and additive faults as well as derivations generated by FDI algorithms. By following the model-matching strategy...

  5. Estimator-based multiobjective robust control strategy for an active pantograph in high-speed railways

    DEFF Research Database (Denmark)

    Lu, Xiaobing; Liu, Zhigang; Song, Yang

    2017-01-01

    Active control of the pantograph is one of the promising measures for decreasing fluctuation in the contact force between the pantograph and the catenary. In this paper, an estimator-based multiobjective robust control strategy is proposed for an active pantograph, which consists of a state estim...

  6. Identification and robust water level control of horizontal steam generators using quantitative feedback theory

    Energy Technology Data Exchange (ETDEWEB)

    Safarzadeh, O., E-mail: O_Safarzadeh@sbu.ac.ir [Shahid Beheshti University, P.O. Box: 19839-63113, Tehran (Iran, Islamic Republic of); Khaki-Sedigh, A. [K. N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Shirani, A.S. [Shahid Beheshti University, P.O. Box: 19839-63113, Tehran (Iran, Islamic Republic of)

    2011-09-15

    Highlights: {yields} A robust water level controller for steam generators (SGs) is designed based on the Quantitative Feedback Theory. {yields} To design the controller, fairly accurate linear models are identified for the SG. {yields} The designed controller is verified using a developed novel global locally linear neuro-fuzzy model of the SG. {yields} Both of the linear and nonlinear models are based on the SG mathematical thermal-hydraulic model developed using the simulation computer code. {yields} The proposed method is easy to apply and guarantees desired closed loop performance. - Abstract: In this paper, a robust water level control system for the horizontal steam generator (SG) using the quantitative feedback theory (QFT) method is presented. To design a robust QFT controller for the nonlinear uncertain SG, control oriented linear models are identified. Then, the nonlinear system is modeled as an uncertain linear time invariant (LTI) system. The robust designed controller is applied to the nonlinear plant model. This nonlinear model is based on a locally linear neuro-fuzzy (LLNF) model. This model is trained using the locally linear model tree (LOLIMOT) algorithm. Finally, simulation results are employed to show the effectiveness of the designed QFT level controller. It is shown that it will ensure the entire designer's water level closed loop specifications.

  7. Optimal and Robust Switching Control Strategies : Theory, and Applications in Traffic Management

    NARCIS (Netherlands)

    Hajiahmadi, M.

    2015-01-01

    Macroscopic modeling, predictive and robust control and route guidance for large-scale freeway and urban traffic networks are the main focus of this thesis. In order to increase the efficiency of our control strategies, we propose several mathematical and optimization techniques. Moreover, in the

  8. Robust nonlinear control design with application to a marine cooling system

    DEFF Research Database (Denmark)

    Hansen, Michael; Stoustrup, Jakob; Bendtsen, Jan Dimon

    2012-01-01

    In this paper we consider design of control laws for a class of nonlinear systems with time-varying state delays by use of principles from feedback linearization. To deal with model uncertainties and delay mismatches, a robust linear H-inf controller is designed for the feedback linearized system...

  9. Design, implementation and testing of a fuzzy control scheme for laser welding

    NARCIS (Netherlands)

    Jauregui Becker, Juan Manuel; Aalderink, B.J.; Aalderink, Benno; Aarts, Ronald G.K.M.; Olde Benneker, Jeroen; Meijer, J.

    2008-01-01

    A fuzzy logic controller (FLC) scheme has been developed for laser welding. Process light emissions are measured and combined to determine the current status of the welding process. If the process is not in a desired welding state, the FLC will adapt the laser power. The FLC has been demonstrated

  10. Design and implementation of a topology control scheme for wireless mesh networks

    CSIR Research Space (South Africa)

    Mudali, P

    2009-09-01

    Full Text Available investigate the feasibility of power control in a popular WMN backbone device and design and evaluate an autonomous, light-weight TC scheme called PlainTC. An indoor test-bed evaluation shows that PlainTC is able to maintain network connectivity, achieve...

  11. ROBUST MIXED H2/H8 ACTIVE VIBRATION CONTROLLER IN ATTENUATION OF SMART BEAM

    Directory of Open Access Journals (Sweden)

    Atta Oveisi

    2014-12-01

    Full Text Available The lack of robustness of the mechanical systems due to the unmodeled dynamics and the external disturbances withholds the performance and optimality of the structures. In this paper, this deficiency is obviated in order to reach the desired robust stability and performance on smart structures. For this purpose a multi-objective robust control strategy is proposed for vibration suppression of a clamped-free smart beam with piezoelectric actuator and vibrometer sensor in an LMI framework which is capable of handling weighted exogenous input signals and provides desired pole placement and robust performance at the same time. An accurate model of a homogeneous beam is derived by means of the finite element modal analysis. Then a low order modal system is considered as the nominal model and remaining modes are left as the multiplicative unstructured uncertainty. Next, a robust controller with a regional pole placement constraint is designed based on the augmented plant composed of the nominal model and its accompanied uncertainty by solving a convex optimization problem. Finally, the robustness of the uncertain closed-loop model and the effect of performance index weights on the system output are investigated both in simulation and practice.

  12. Dynamic optimization and robust explicit model predictive control of hydrogen storage tank

    KAUST Repository

    Panos, C.

    2010-09-01

    We present a general framework for the optimal design and control of a metal-hydride bed under hydrogen desorption operation. The framework features: (i) a detailed two-dimension dynamic process model, (ii) a design and operational dynamic optimization step, and (iii) an explicit/multi-parametric model predictive controller design step. For the controller design, a reduced order approximate model is obtained, based on which nominal and robust multi-parametric controllers are designed. © 2010 Elsevier Ltd.

  13. Explicit robust constrained control for linear systems : analysis, implementation and design based on optimization

    OpenAIRE

    Nguyen, Ngoc Anh

    2015-01-01

    Piecewise affine (PWA) feedback control laws have received significant attention due to their relevance for the control of constrained systems, hybrid systems; equally for the approximation of nonlinear control. However, they are associated with serious implementation issues. Motivated from the interest in this class of particular controllers, this thesis is mostly related to their analysis and design.The first part of this thesis aims to compute the robustness and fragility margins for a giv...

  14. H∞ robust control of load frequency in diesel-battery hybrid electric propulsion ship

    Directory of Open Access Journals (Sweden)

    LI Hongyue

    2017-05-01

    Full Text Available Considering the load frequency fluctuation in the shipboard integrated power system caused by such stochastic uncertainty as wind, wave and current, the battery is adopted here to compensate for the difference between diesel generator output power and ship demand power, and the secondary frequency control is used for the diesel generator to guarantee the power balance in the shipboard integrated power system and suppress the frequency fluctuation. The load frequency control problem is modeled as a state space equation, the robust controller is designed by selecting the appropriate sensitivity function and complementary sensitivity function based on the H∞ mixed sensitivity principle, and the controller is solved by the linear matrix inequality(LMIapproach. The amplitude frequency characteristics denote the reasonability of the designed controller and the design requirement is satisfied by the impact of the impulse signal. The simulation results show that, compared with the classical PI controller, the controller designed by the H∞ robust method can significantly suppress frequency fluctuation under stochastic uncertainty, and improve the power variation of the diesel generator, battery and state of charge(SOC. The robust stability and robust performance of the power system are also advanced.

  15. A Reconfiguration Control Scheme for a Quadrotor Helicopter via Combined Multiple Models

    Directory of Open Access Journals (Sweden)

    Fuyang Chen

    2014-08-01

    Full Text Available In this paper, an optimal reconfiguration control scheme is proposed for a quadrotor helicopter with actuator faults via adaptive control and combined multiple models. The combined models set contains several fixed models, an adaptive model and a reinitialized adaptive model. The fixed models and the adaptive model can describe the failure system under different fault conditions. Moreover, the proposed reinitialized adaptive model refers to the closest model of the current system and can improve the speed of convergence effectively. In addition, the reference model is designed in consideration of an optimal control performance index and the principle of the minimum cost to achieve perfect tracking performance. Finally, some simulation results demonstrate the effectiveness of the proposed reconfiguration control scheme for faulty cases.

  16. A Power System Emergency Control Scheme in the Presence of High Wind Power Penetration

    DEFF Research Database (Denmark)

    Hoseinzadeh, Bakhtyar

    . Utilization of all of locally measurable variables, e.g. frequency, its rate of change, voltage drop, power flow direction under an integrated decentralized plan is done in this project, in order to improve the grid reliability. The proposed scheme benefits from a decentralized strategy, which reduces....... The load-frequency control as an ancillary service provided by renewable energy sources and load shedding as an emergency control should be localized. It means that the active power deficit should be compensated locally at vicinity of event location in order to avoid transferring the demanded active power...... from distant units to the incidence place. In this thesis, localization of both load-frequency control an load shedding are fulfilled using locally measured voltage drop data in the decentralized control strategy. The proposed load shedding scheme is coordinated with existing plant protection relays...

  17. Identity driven Capability based Access Control (ICAC) Scheme for the Internet of Things

    DEFF Research Database (Denmark)

    Mahalle, Parikshit N.; Anggorojati, Bayu; Prasad, Neeli R.

    2012-01-01

    Internet of Things (IoT) becomes discretionary part of everyday life. Scalability and manageability is daunting due to unbounded number of devices and services. Access control and authorization in IoT with least privilege is equally important to establish secure communication between multiple...... devices and services. In this paper, the concept of capability for access control is introduced where the identities of the involved devices are entrenched in the access capabilities. Identity driven capability based access control (ICAC) scheme presented in this paper helps to alleviate issues related...... to complexity and dynamics of device identities. ICAC is implemented for 802.11 and results shows that ICAC has less scalability issues and better performance analysis compared with other access control schemes. The ICAC evaluation by using security protocol verification tool shows that ICAC is secure against...

  18. Study on Control Scheme for the Inverters in Low Voltage Microgrid with Nonlinear Loads

    Science.gov (United States)

    Xu, Jiqiang; Lu, Wenzhou; Wu, Lei

    2017-05-01

    There are a lot of nonlinear loads in real low voltage microgrid system. It will cause serious output voltage and grid current harmonic distortions problems in island and grid-connected modes, respectively. To solve this problem, this paper proposes a droop control scheme with quasi-proportion and resonant (quasi-PR) controller based on αβ stationary reference frame to make microgrid smoothly switch between grid-connected and island modes without changing control method. Moreover, in island mode, not only stable output voltage and frequency, but also reduced output voltage harmonics with added nonlinear loads can be achieved; In grid-connected mode, not only constant power, but also reduced grid current harmonics can be achieved. Simulation results verify the effectiveness of the proposed control scheme.

  19. Hierarchical Control Scheme for Improving Transient Voltage Recovery of a DFIG-Based WPP

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinho; Muljadi, Eduard; Kang, Yong Cheol

    2015-06-05

    Modern grid codes require that wind power plants (WPPs) inject reactive power according to the voltage dip at a point of interconnection (POI). This requirement helps to support a POI voltage during a fault. However, if a fault is cleared, the POI and wind turbine generator (WTG) voltages are likely to exceed acceptable levels unless the WPP reduces the injected reactive power quickly. This might deteriorate the stability of a grid by allowing the disconnection of WTGs to avoid any damage. This paper proposes a hierarchical control scheme of a doubly-fed induction generator (DFIG)-based WPP. The proposed scheme aims to improve the reactive power injecting capability during the fault and suppress the overvoltage after the fault clearance. To achieve the former, an adaptive reactive power-to-voltage scheme is implemented in each DFIG controller so that a DFIG with a larger reactive power capability will inject more reactive power. To achieve the latter, a washout filter is used to capture a high frequency component contained in the WPP voltage, which is used to remove the accumulated values in the proportional-integral controllers. Test results indicate that the scheme successfully supports the grid voltage during the fault, and recovers WPP voltages without exceeding the limit after the fault clearance.

  20. A Practical Tuning Method for the Robust PID Controller with Velocity Feed-Back

    Directory of Open Access Journals (Sweden)

    Emre Sariyildiz

    2015-08-01

    Full Text Available Proportional-Integral-Derivative (PID control is the most widely used control method in industrial and academic applications due to its simplicity and efficiency. Several different control methods/algorithms have been proposed to tune the gains of PID controllers. However, the conventional tuning methods do not have sufficient performance and simplicity for practical applications, such as robotics and motion control. The performance of motion control systems may significantly deteriorate by the nonlinear plant uncertainties and unknown external disturbances, such as inertia variations, friction, external loads, etc., i.e., there may be a significant discrepancy between the simulation and experiment if the robustness is not considered in the design of PID controllers. This paper proposes a novel practical tuning method for the robust PID controller with velocity feed-back for motion control systems. The main advantages of the proposed method are the simplicity and efficiency in practical applications, i.e., a high performance robust motion control system can be easily designed by properly tuning conventional PID controllers. The validity of the proposal is verified by giving simulation and experimental results.