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Sample records for active suspension systems

  1. An LPV Control Approach for Comfort and Suspension Travel Improvements of Semi-Active Suspension Systems

    Do, Anh Lam; Spelta, Cristiano; Savaresi, Sergio,; Sename, Olivier; Dugard, Luc; Delvecchio, Diego

    2010-01-01

    International audience In this paper, we present a new H¥=LPV control method to improve the trade-off between comfort and suspension travel. Firstly, a semi-active automotive suspension uipped with a nonlinear static semi-active damper is presented. Secondly, the semi-active suspension system is reformulated in the LPV framework which can be handled in a polytopic way. Finally, in numerical analysis, to emphasize the performance of the proposed controller, the end-stop event is introduced....

  2. Performance of a novel energy-regenerative active suspension system

    HUANG Da-shan; ZHANG Jin-qiu; LIU Yi-le; WANG Xing-ye

    2015-01-01

    A novel energy-regenerative active suspension (NEAS) system was designed to solve the problem of low energy recovery efficiency caused by frequent alternation of energy-recovery mode and active-control mode in a traditional energy-regenerative active suspension (TEAS) system. The energy recovery and active control could be implemented simultaneously in the NEAS. The transforming processes and the corresponding computational formulas of power conversion in the NEAS were provided. The simulation results show that the performances of energy recovery of the NEAS are improved, and the self-sustaining of power supply for the NEAS can be realized.

  3. Quarter Car Active Suspension System Control Using PID Controller tuned by PSO

    Wissam H. Al-Mutar

    2015-01-01

    The objective of this paper is to design an efficient control scheme for car suspension system. The purpose of suspension system in vehicles is to get more comfortable riding and good handling with road vibrations. A nonlinear hydraulic actuator is connected to passive suspension system in parallel with damper. The Particles Swarm Optimization is used to tune a PID controller for active suspension system. The designed controller is applied for quarter car suspension system and result is compa...

  4. Active Electromechanical Suspension System for Planetary Rovers Project

    National Aeronautics and Space Administration — Balcones Technologies, LLC proposes to adapt actively controlled suspension technology developed by The University of Texas at Austin Center for Electromechanics...

  5. Quarter Car Active Suspension System Control Using PID Controller tuned by PSO

    Wissam H. Al-Mutar

    2015-07-01

    Full Text Available The objective of this paper is to design an efficient control scheme for car suspension system. The purpose of suspension system in vehicles is to get more comfortable riding and good handling with road vibrations. A nonlinear hydraulic actuator is connected to passive suspension system in parallel with damper. The Particles Swarm Optimization is used to tune a PID controller for active suspension system. The designed controller is applied for quarter car suspension system and result is compared with passive suspension system model and input road profile. Simulation results show good performance for the designed controller

  6. Robust Vehicle Suspension System by Converting Active & Passive Control of a Vehicle to Semi-Active Control System Analytically

    Hassan Elahi; Dr. Riffat Asim Pasha; Dr. Asif Israr; Dr. M. Zubair Khan

    2014-01-01

    In this research work a simplified translational model of an automotive suspension system is constructed by only considering the translation motion of one wheel of a car. Passive Vehicle Suspension System is converted into Semi Active Vehicle System. Major advantage achieved by this system is that it adjusts the damping of the suspension system without the application of any actuator by using MATLAB® simulations. The semi-active control is found to control the vibration of suspens...

  7. Improving the Dynamics of Suspension Bridges using Active Control Systems

    Thoft-Christensen, Palle

    Improving the dynamics of suspension bridge using active control is discussed in this paper. The main dynamic problem with long suspension bridges is the aeroelastic phenomenon called flutter. Flutter oscillations of a bridge girder is a stability problem and the oscillations are perpendicular to...... the direction of the wind and occur when the bridge is exposed to wind velocity above critical value called the flutter wind velocity Ucr....

  8. Fuzzy-Skyhook Control for Active Suspension Systems Applied to a Full Vehicle Model

    Aref M.A. Soliman

    2012-04-01

    Full Text Available Nowadays, most modern vehicles are equipped with controlled suspension systems for improving the vehicle ride comfort. Therefore, this paper is concerned with a theoretical study for the ride comfort performance of the vehicle. The theoretical investigation includes a suggestion of an active suspension system controller using fuzzy-skyhook control theory, which offers new opportunities for the improvement of vehicle ride performance. The ride comfort of the active suspension system has been evaluated using a 7 degree of freedom full vehicle mathematical model. The simulation results are presented in the time and frequency domain, also in terms of RMS values, and it’s shown that the proposed active suspension system with fuzzy-skyhook control improved the vehicle ride quality in terms of body acceleration, suspension working space and dynamic tyre load in comparison with the passive and skyhook suspension systems.

  9. Gold enrichment in active geothermal systems by accumulating colloidal suspensions

    Hannington, Mark; Harðardóttir, Vigdis; Garbe-Schönberg, Dieter; Brown, Kevin L.

    2016-04-01

    The origins of high-grade hydrothermal ore deposits are debated, but active geothermal systems provide important clues to their formation. The highest concentrations of gold are found in geothermal systems with direct links to island arc magmatism. Yet, similar concentrations have also been found in the absence of any input from arc magmas, for example, in the Reykjanes geothermal field, Iceland. Here we analyse brine samples taken from deep wells at Reykjanes and find that gold concentrations in the reservoir zone have increased over the past seven years from an average of 3 ppb to 14 ppb. The metal concentrations greatly exceed the maximum solubility of gold in the reservoir under saturated conditions and are now nearly two orders of magnitude higher than in mid-ocean ridge black smoker fluids--the direct analogues of Reykjanes deep liquids. We suggest that ongoing extraction of brine, the resulting pressure drop, and increased boiling have caused gold to drop out of solution and become trapped in the reservoir as a colloidal suspension. This process may explain how the stock of metal in the reservoirs of fossil geothermal systems could have increased over time and thus become available for the formation of gold-rich ore deposits.

  10. ACTIVE CONTROL OF QUARTER-CAR SUSPENSION SYSTEM USING LINEAR QUADRATIC REGULATOR

    V.M. Nandedkar

    2011-06-01

    Full Text Available The automobile is composed of many systems. One of these is the suspension system. The main functions of the automotive suspension system are to provide vehicle support, stability and directional control during handling manoeuvres and to provide effective isolation from road disturbances. The suspension system has to balance the tradeoff between ride comfort and handling performance. This paper analyses the passive suspension system and active suspension system using a Linear Quadratic Regulator (LQR controller. A linear quarter-car model is used for the analysis and simulation. The performance of the LQR controller is compared with the passive suspension system. The simulation results show that the LQR controller improves vehicle ride comfort.

  11. The Active Fractional Order Control for Maglev Suspension System

    Peichang Yu

    2015-01-01

    Full Text Available Maglev suspension system is the core part of maglev train. In the practical application, the load uncertainties, inherent nonlinearity, and misalignment between sensors and actuators are the main issues that should be solved carefully. In order to design a suitable controller, the attention is paid to the fractional order controller. Firstly, the mathematical model of a single electromagnetic suspension unit is derived. Then, considering the limitation of the traditional PD controller adaptation, the fractional order controller is developed to obtain more excellent suspension specifications and robust performance. In reality, the nonlinearity affects the structure and the precision of the model after linearization, which will degrade the dynamic performance. So, a fractional order controller is addressed to eliminate the disturbance by adjusting the parameters which are added by the fractional order controller. Furthermore, the controller based on LQR is employed to compare with the fractional order controller. Finally, the performance of them is discussed by simulation. The results illustrated the validity of the fractional order controller.

  12. Fuzzy logic control for active bus suspension system

    In this study an active controller is presented for vibration suppression of a full-bus suspension model that use air spring. Since the air spring on the full-bus model may face different working conditions, auxiliary chambers have been designed. The vibrations, caused by the irregularities of the road surfaces, are tried to be suppressed via a multi input-single output fuzzy logic controller. The effect of changes in the number of auxiliary chambers on the vehicle vibrations is also investigated. The numerical results demonstrate that the presented fuzzy logic controller improves both ride comfort and road holding.

  13. Analysis of semi-active vehicle suspension system using airspring and MR damper

    Tesfay, A. H.; Goel, V. K.

    2015-12-01

    With the new advancements in vibration control strategies and controllable actuator manufacturing, semi-active actuators and dampers are finding their way as an essential part of vibration isolators, particularly in vehicle suspension systems. This is attributed to the fact that in a semi-active system, the damping coefficients can be adjusted to improve ride comfort and road handling performances. The currently available semi-active damper technology uses MR fluid to control the damping characteristics of the suspension system. In addition to MR dampers, combining air springs in a semi-active suspension system leads to better handling and ride performance in vehicles. Furthermore, the use of air spring in semi-active suspension system helps to ease design of variable spring stiffness. This easy design opportunity leads to independent control of stiffness and ride height of the vehicle. This paper deals with the design and modelling of variable stiffness air spring for semi-active suspension system, modelling of semi-active suspension systems with variable stiffness and MR damper, and study their

  14. Functional Based Adaptive and Fuzzy Sliding Controller for Non-Autonomous Active Suspension System

    Huang, Shiuh-Jer; Chen, Hung-Yi

    In this paper, an adaptive sliding controller is developed for controlling a vehicle active suspension system. The functional approximation technique is employed to substitute the unknown non-autonomous functions of the suspension system and release the model-based requirement of sliding mode control algorithm. In order to improve the control performance and reduce the implementation problem, a fuzzy strategy with online learning ability is added to compensate the functional approximation error. The update laws of the functional approximation coefficients and the fuzzy tuning parameters are derived from the Lyapunov theorem to guarantee the system stability. The proposed controller is implemented on a quarter-car hydraulic actuating active suspension system test-rig. The experimental results show that the proposed controller suppresses the oscillation amplitude of the suspension system effectively.

  15. Controls of maglev suspension systems

    Cai, Y.; Zhu, S.; Chen, S.S.; Rote, D.M.

    1993-06-01

    This study investigates alternative control designs of maglev vehicle suspension systems. Active and semi-active control law designs are introduced into primary and secondary suspensions of maglev vehicles. A one-dimensional vehicle with two degrees of freedom, to simulate the German Transrapid Maglev System, is used for suspension control designs. The transient and frequency responses of suspension systems and PSDs of vehicle accelerations are calculated to evaluate different control designs. The results show that active and semi-active control designs indeed improve the response of vehicle and provide an acceptable ride comfort for maglev systems.

  16. A semi-active control suspension system for railway vehicles with magnetorheological fluid dampers

    Wei, Xiukun; Zhu, Ming; Jia, Limin

    2016-07-01

    The high-speed train has achieved great progress in the last decades. It is one of the most important modes of transportation between cities. With the rapid development of the high-speed train, its safety issue is paid much more attention than ever before. To improve the stability of the vehicle with high speed, extra dampers (i.e. anti-hunting damper) are used in the traditional bogies with passive suspension system. However, the curving performance of the vehicle is undermined due to the extra lateral force generated by the dampers. The active suspension systems proposed in the last decades attempt to solve the vehicle steering issue. However, the active suspension systems need extra actuators driven by electrical power or hydraulic power. There are some implementation and even safety issues which are not easy to be overcome. In this paper, an innovative semi-active controlled lateral suspension system for railway vehicles is proposed. Four magnetorheological fluid dampers are fixed to the primary suspension system of each bogie. They are controlled by online controllers for enhancing the running stability on the straight track line on the one hand and further improving the curving performance by controlling the damper force on the other hand. Two control strategies are proposed in the light of the pure rolling concept. The effectiveness of the proposed strategies is demonstrated by SIMPACK and Matlab co-simulation for a full railway vehicle with two conventional bogies.

  17. A new controller for the seni-active suspension system with magnetor heological dampers

    2003-01-01

    A new sliding mode controller for semi-active suspension system with magnetorheological (MR) damper is presented in this paper. In the proposed sliding mode controller, a semi-active suspension based on the skyhook damper system is chosen as the reference model to be followed, and the control law is so determined that the asymptotically stable error dynamics occurs between the controlled state and the reference model state. Numerical simulations are carried out to study the performance of the new sliding mode controller. The results show that the proposed controller yields almost perfect tracking to the reference model and has a high robustness against model parameter uncertainties and disturbances.

  18. A tunable fuzzy logic controller for the vehicle semi-active suspension system

    方子帆; DENG; Zhaoxiang; 等

    2002-01-01

    On the basis of analyzing the system constitution of vehicle semi-active suspension,a 4-DOF(degree of freedom)dynamic model is established.A tunable fuzzy logic controller is designed by using without quantification method and taking into account the uncertainty,nonlinearity and complexity of parameters for a vehicle suspension system.Simulation to test the performance of this controller is performed under random excitations and definite disturbances of a C grade road,and the effects of time delay and changes of system parameters on the vehicle suspension system are researched.The numerical simulation shows that the performance of the designed tunable fuzzy logic controller is effective,stable and reliable.

  19. Analysis of Active and Passive Suspension System of Half Car model using MatlabTM - Simulink®

    Ajay Dusane,; Akshay Jadhav,; Abhijit Gaikwad,

    2014-01-01

    The concept of using an active suspension system for vehicles is to provide the best performance of car controlling. A fully active suspension system aim is to control the suspension over the range of excitation signals. It is considered to be the way of increasing load carrying, handling and ride quality. The purpose of this research paper is to construct a half car model with a linear control design which is the Proportional Integral Derivatives (PID).This paper compares the ...

  20. Electrorheological Damper and Its Application for Semi-Active Suspension System

    ZHAO Xia; ZHANG Yong-fa

    2007-01-01

    A semi-active control of vehicle suspension system with electrorheological (ER) damper is presented.ER fluid characteristics are introduced based on the Bingham plasticity model first.Then ER damper working force is given.Finally a quarter car model with ER damper is constructed.The skyhook control strategy is adopted to simulate the amplitude-frequency characteristics and the vibration of suspension system under random road excitation on the basis of ER damper characteristics.The response curves of the vertical acceleration,the suspension dynamic working space and the tyre dynamic loading are obtained.Simulation results show that the acceleration is reduced effectively and then the ride comfort is improved by the skyhook control law.

  1. Active Control of Suspension Bridges

    Thoft-Christensen, Palle

    In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps are...

  2. Design and experiment study of a semi-active energy-regenerative suspension system

    Shi, Dehua; Chen, Long; Wang, Ruochen; Jiang, Haobin; Shen, Yujie

    2015-01-01

    A new kind of semi-active energy-regenerative suspension system is proposed to recover suspension vibration energy, as well as to reduce the suspension cost and demands for the motor-rated capacity. The system consists of an energy-regenerative damper and a DC-DC converter-based energy-regenerative circuit. The energy-regenerative damper is composed of an electromagnetic linear motor and an adjustable shock absorber with three regulating levels. The linear motor just works as the generator to harvest the suspension vibration energy. The circuit can be used to improve the system’s energy-regenerative performance and to continuously regulate the motor’s electromagnetic damping force. Therefore, although the motor works as a generator and damps the isolation without an external power source, the motor damping force is controllable. The damping characteristics of the system are studied based on a two degrees of freedom vehicle vibration model. By further analyzing the circuit operation characteristics under different working modes, the double-loop controller is designed to track the desired damping force. The external-loop is a fuzzy controller that offers the desired equivalent damping. The inner-loop controller, on one hand, is used to generate the pulse number and the frequency to control the angle and the rotational speed of the step motor; on the other hand, the inner-loop is used to offer the duty cycle of the energy-regenerative circuit. Simulations and experiments are conducted to validate such a new suspension system. The results show that the semi-active energy-regenerative suspension can improve vehicle ride comfort with the controllable damping characteristics of the linear motor. Meanwhile, it also ensures energy regeneration.

  3. Design and experiment study of a semi-active energy-regenerative suspension system

    A new kind of semi-active energy-regenerative suspension system is proposed to recover suspension vibration energy, as well as to reduce the suspension cost and demands for the motor-rated capacity. The system consists of an energy-regenerative damper and a DC-DC converter-based energy-regenerative circuit. The energy-regenerative damper is composed of an electromagnetic linear motor and an adjustable shock absorber with three regulating levels. The linear motor just works as the generator to harvest the suspension vibration energy. The circuit can be used to improve the system’s energy-regenerative performance and to continuously regulate the motor’s electromagnetic damping force. Therefore, although the motor works as a generator and damps the isolation without an external power source, the motor damping force is controllable. The damping characteristics of the system are studied based on a two degrees of freedom vehicle vibration model. By further analyzing the circuit operation characteristics under different working modes, the double-loop controller is designed to track the desired damping force. The external-loop is a fuzzy controller that offers the desired equivalent damping. The inner-loop controller, on one hand, is used to generate the pulse number and the frequency to control the angle and the rotational speed of the step motor; on the other hand, the inner-loop is used to offer the duty cycle of the energy-regenerative circuit. Simulations and experiments are conducted to validate such a new suspension system. The results show that the semi-active energy-regenerative suspension can improve vehicle ride comfort with the controllable damping characteristics of the linear motor. Meanwhile, it also ensures energy regeneration. (paper)

  4. FPGA Based Adaptive Neuro Fuzzy Inference Controller for Full Vehicle Nonlinear Active Suspension Systems

    Ammar A. Aldair

    2010-10-01

    Full Text Available A Field Programmable Gate Array (FPGA is proposed to build an Adaptive Neuro Fuzzy Inference System (ANFIS for controlling a full vehicle nonlinear active suspension system. A Very High speed integrated circuit Hardware Description Language (VHDL has been used to implement the proposed controller. An optimal Fraction Order PIλ D µ (FOPID controller is designed for a full vehicle nonlinear active suspension system. Evolutionary Algorithm (EA has been applied to modify the five parameters of the FOPID controller (i.e. proportional constant Kp, integral constant Ki , derivative constant Kd, integral order λ and derivative order µ. The data obtained from the FOPID controller are used as a reference to design the ANFIS model as a controller for the controlled system. A hybrid approach is introduced to train the ANFIS. A Matlab Program has been used to design and simulate the proposed controller. The ANFIS control parameters obtained from the Matlab program are used to write the VHDL codes. Hardware implementation of the FPGA is dependent on the configuration file obtained from the VHDL program. The experimental results have proved the efficiency and robustness of the hardware implementation for the proposed controller. It provides a novel technique to be used to design NF controller for full vehicle nonlinear active suspension systems with hydraulic actuators.

  5. Active seat suspension for a small vehicle: considerations for control system including observer

    Katsumata, Hiroyuki; Shiino, Hiroshi; Oshinoya, Yasuo; Ishibashi, Kazuhisa; Ozaki, Koichi; Ogino, Hirohiko

    2007-12-01

    We have examined the improvement of ride quality and the reduction of riding fatigue brought about by the active control of the seat suspension of small vehicles such as one-seater electric automobiles. A small active seat suspension, which is easy to install, was designed and manufactured for one-seater electric automobiles. For the actuator, a maintenance-free voice coil motor used as a direct drive was adopted. For fundamental considerations, we designed a one-degree-of-freedom model for the active seat suspension system. Then, we designed a disturbance cancellation control system that includes the observer for a two-degree-of-freedom model. In an actual driving test, a test road, in which the concavity and convexity of an actual road surface were simulated using hard rubber, was prepared and the control performance of vertical vibrations of the seat surface during driving was examined. As a result, in comparison with the one-degree-of-freedom control system, it was confirmed that the control performance was improved by the two-degree-of-freedom control system that includes the observer.

  6. Optimization of mechatronic systems: application to a modern car equipped with a semi-active suspension

    Duysinx, Pierre; Bruls, Olivier; Collard, Jean-François; Fisette, Paul; Lauwerys, Christophe; Swevers, Jan

    2005-01-01

    The research aims at developing a global mechatronic approach to model, simulate and optimize complex industrial applications. The approach is illustrated with the simulation and the optimization of a modern car (an Audi A6) equipped with a controlled semi-active suspension. An optimization procedure is used to find the best sub-system parameters in order to improve the comfort of the passengers while preserving the car ride and handling performances. Two different modeling and optimization a...

  7. FxLMS Method for Suppressing In-Wheel Switched Reluctance Motor Vertical Force Based on Vehicle Active Suspension System

    Yan-yang Wang

    2014-01-01

    Full Text Available The vibration of SRM obtains less attention for in-wheel motor applications according to the present research works. In this paper, the vertical component of SRM unbalanced radial force, which is named as SRM vertical force, is taken into account in suspension performance for in-wheel motor driven electric vehicles (IWM-EV. The analysis results suggest that SRM vertical force has a great effect on suspension performance. The direct cause for this phenomenon is that SRM vertical force is directly exerted on the wheel, which will result in great variation in tyre dynamic load and the tyre will easily jump off the ground. Furthermore, the frequency of SRM vertical force is broad which covers the suspension resonance frequencies. So it is easy to arouse suspension resonance and greatly damage suspension performance. Aiming at the new problem, FxLMS (filtered-X least mean square controller is proposed to improve suspension performance. The FxLMS controller is based on active suspension system which can generate the controllable force to suppress the vibration caused by SRM vertical force. The conclusion shows that it is effective to take advantage of active suspensions to reduce the effect of SRM vertical force on suspension performance.

  8. Robust fault-tolerant H∞ control of active suspension systems with finite-frequency constraint

    Wang, Rongrong; Jing, Hui; Karimi, Hamid Reza; Chen, Nan

    2015-10-01

    In this paper, the robust fault-tolerant (FT) H∞ control problem of active suspension systems with finite-frequency constraint is investigated. A full-car model is employed in the controller design such that the heave, pitch and roll motions can be simultaneously controlled. Both the actuator faults and external disturbances are considered in the controller synthesis. As the human body is more sensitive to the vertical vibration in 4-8 Hz, robust H∞ control with this finite-frequency constraint is designed. Other performances such as suspension deflection and actuator saturation are also considered. As some of the states such as the sprung mass pitch and roll angles are hard to measure, a robust H∞ dynamic output-feedback controller with fault tolerant ability is proposed. Simulation results show the performance of the proposed controller.

  9. Signal frequency based self-tuning fuzzy controller for semi-active suspension system

    孙涛; 黄震宇; 陈大跃; 汤磊

    2003-01-01

    A new kind of fuzzy control scheme, based on the identification of the signal' s main frequency and the behavior of the ER damper, is proposed to control the semi-active suspension system. This method ad-justs the fuzzy controller to achieve the best isolation effect by analyzing the main frequency' s characters and inspecting the change of system parameters. The input of the fuzzy controller is the main frequency and the op-timal damping ratio is the output. Simulation results indicated that the proposed control method is very effec-tive in isolating the vibration.

  10. Active suspension for a field sprayer boom

    Nielsen, Henrik Skovsgaard; Sørensen, Paul Haase

    1998-01-01

    The possibilities of implementing an active boom suspension is investigated. The performance improvement of an active suspension over a traditional passive one is studied in simulation, and shows a significant improvement. A closed-loop control system involving two ultrasonic distance transducers...

  11. FPGA BASED ADAPTIVE NEURO FUZZY INFERENCE CONTROLLER FOR FULL VEHICLE NONLINEAR ACTIVE SUSPENSION SYSTEMS

    Weiji Wang

    2010-10-01

    Full Text Available A Field Programmable Gate Array (FPGA is proposed to build an Adaptive Neuro Fuzzy Inference System(ANFIS for controlling a full vehicle nonlinear active suspension system. A Very High speed integratedcircuit Hardware Description Language (VHDL has been used to implement the proposed controller. Anoptimal Fraction Order PIlDμ (FOPID controller is designed for a full vehicle nonlinear activesuspension system. Evolutionary Algorithm (EA has been applied to modify the five parameters of theFOPID controller (i.e. proportional constant Kp, integral constant Ki, derivative constant Kd, integralorder l and derivative order μ. The data obtained from the FOPID controller are used as a reference todesign the ANFIS model as a controller for the controlled system. A hybrid approach is introduced to trainthe ANFIS. A Matlab Program has been used to design and simulate the proposed controller. The ANFIScontrol parameters obtained from the Matlab program are used to write the VHDL codes. Hardwareimplementation of the FPGA is dependent on the configuration file obtained from the VHDL program. Theexperimental results have proved the efficiency and robustness of the hardware implementation for theproposed controller. It provides a novel technique to be used to design NF controller for full vehiclenonlinear active suspension systems with hydraulic actuators.

  12. Adaptive Neural-Sliding Mode Control of Active Suspension System for Camera Stabilization

    Feng Zhao

    2015-01-01

    Full Text Available The camera always suffers from image instability on the moving vehicle due to the unintentional vibrations caused by road roughness. This paper presents a novel adaptive neural network based on sliding mode control strategy to stabilize the image captured area of the camera. The purpose is to suppress vertical displacement of sprung mass with the application of active suspension system. Since the active suspension system has nonlinear and time varying characteristics, adaptive neural network (ANN is proposed to make the controller robustness against systematic uncertainties, which release the model-based requirement of the sliding model control, and the weighting matrix is adjusted online according to Lyapunov function. The control system consists of two loops. The outer loop is a position controller designed with sliding mode strategy, while the PID controller in the inner loop is to track the desired force. The closed loop stability and asymptotic convergence performance can be guaranteed on the basis of the Lyapunov stability theory. Finally, the simulation results show that the employed controller effectively suppresses the vibration of the camera and enhances the stabilization of the entire camera, where different excitations are considered to validate the system performance.

  13. MULTI OBJECTIVE OPTIMIZATION OF VEHICLE ACTIVE SUSPENSION SYSTEM USING DEBBO BASED PID CONTROLLER

    Kalaivani Rajagopal

    2014-03-01

    Full Text Available This paper proposes the Multi Objective Optimization (MOO of Vehicle Active Suspension System (VASS with a hybrid Differential Evolution (DE based Biogeography-Based Optimization (BBO (DEBBO for the parameter tuning of Proportional Integral Derivative (PID controller. Initially a conventional PID controller, secondly a BBO, an rising nature enthused global optimization procedure based on the study of the ecological distribution of biological organisms and a hybridized DEBBO algorithm which inherits the behaviours of BBO and DE have been used to find the tuning parameters of the PID controller to improve the performance of VASS by considering a MOO function as the performance index. Simulations of passive system, active system having PID controller with and without optimizations have been performed by considering dual and triple bump kind of road disturbances in MATLAB/Simulink environment. The simulation results show the effectiveness of DEBBO based PID (DEBBOPID in achieving the goal.

  14. Pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer

    YOSHIMURAToshio; TAKAGIAtsushi

    2004-01-01

    This paper presents the construction of a pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer. The one-wheel car model can be approximately described as a nonlinear two degrees of freedom system subject to excitation from a road profile. The active control is composed of fuzzy and disturbance controls, and the active control force is constructed by actuating a pneumatic actuator. A phase lead-lag compensator is inserted to counter the performance degradation due to the delay of the pneumatic actuator. The experimental result indicates that the proposed active suspension improves much the vibration suppression of the car model.

  15. SLIDING MODE CONTROL FOR ACTIVE AUTOMOBILE SUSPENSIONS

    1998-01-01

    Nonlinear control methods are presented based on theory of sliding mode control (SMC) or variable structure control (VSC) for application to active automobile suspensions. Requirements of reducing manufacturing cost and energy consumption of the active suspension system may be satisfiedby reasonable design of the sliding surface and hydraulic servo system. Emphasis is placed on the study of the discrete sliding mode control method (DSMC) applicable for a new sort of speed on-off solenoid valves of anti-dust capability and low price. Robustness and effectiveness of the feedback linearized controller in typical road conditions are demonstrated by numerical results fora quarter-car suspension model.

  16. On the achievable performance using variable geometry active secondary suspension systems in commercial vehicles

    Evers, W.J.; Besselink, I.G.M.; Teerhuis, A.P.; Nijmeijer, H.

    2011-01-01

    There is a need to further improve driver comfort in commercial vehicles. The variable geometry active suspension offers an interesting option to achieve this in an energy efficient way. However, the optimal control strategy and the overal performance potential remains unclear. The aim of this paper

  17. On the Benefits of Semi-Active Suspensions with Inerters

    Xin-Jie Zhang

    2012-01-01

    Full Text Available Inerters have become a hot topic in recent years especially in vehicle, train, building suspension systems, etc. Eight different layouts of suspensions were analyzed with a quarter-car model in this paper. Dimensionless root mean square (RMS responses of the sprung mass vertical acceleration, the suspension travel, and the tire deflection are derived which were used to evaluate the performance of the quarter-car model. The behaviour of semi-active suspensions with inerters using Groundhook, Skyhook, and Hybrid control has been evaluated and compared to the performance of passive suspensions with inerters. Sensitivity analysis was applied to the development of a high performance semi-active suspension with an inerter. Numerical simulations indicate that a semi-active suspension with an inerter has much better performance than the passive suspension with an inerter, especially with the Hybrid control method, which has the best compromise between comfort and road holding quality.

  18. Combining support vector machines with linear quadratic regulator adaptation for the online design of an automotive active suspension system

    As a powerful machine-learning approach to pattern recognition problems, the support vector machine (SVM) is known to easily allow generalization. More importantly, it works very well in a high-dimensional feature space. This paper presents a nonlinear active suspension controller which achieves a high level performance by compensating for actuator dynamics. We use a linear quadratic regulator (LQR) to ensure optimal control of nonlinear systems. An LQR is used to solve the problem of state feedback and an SVM is used to address the question of the estimation and examination of the state. These two are then combined and designed in a way that outputs feedback control. The real-time simulation demonstrates that an active suspension using the combined SVM-LQR controller provides passengers with a much more comfortable ride and better road handling

  19. Large gap magnetic suspension system

    Abdelsalam, Moustafa K.; Eyssa, Y. M.

    1991-01-01

    The design of a large gap magnetic suspension system is discussed. Some of the topics covered include: the system configuration, permanent magnet material, levitation magnet system, superconducting magnets, resistive magnets, superconducting levitation coils, resistive levitation coils, levitation magnet system, and the nitrogen cooled magnet system.

  20. 49 CFR 238.427 - Suspension system.

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Suspension system. 238.427 Section 238.427... Equipment § 238.427 Suspension system. (a) General requirements. (1) Suspension systems shall be designed to... equipment. (2) Passenger equipment shall meet the safety performance standards for suspension...

  1. Real Time Vibration Control of Active Suspension System with Active Force Control using Iterative Learning Algorithm

    Kalaivani

    2013-09-01

    Full Text Available This paper presents concurrent vibration control of a laboratory scaled vibration isolator platform with Active Force Control (AFC using Iterative Learning Algorithm (ILA. The work investigates the performance of the traditional Proportional Integral Derivative Controller (PIDC with and without AFC using ILA for vibration suppression. The physical single degree of freedom quarter car has been interfaced with a personal computer using a National Instruments data acquisition card NI USB 6008. The controllers are designed and simulated using LabVIEW simulation software. The results infer that the PIDC with AFC using ILA works superior than the PIDC.

  2. Survey of Controllable Suspension System for Off-road Vehicles

    WU Zhi-cheng; ZHU Quan-min; CHEN Si-zhong; Alan Winfield; YANG Lin; ZHANG Bin

    2007-01-01

    The controllable suspension system can improve the performances of off-road vehicles both on road and cross-country. So far, four controllable suspensions, that is, body height control, active, semi-active and slow-active suspensions, have been developed. For off-road vehicles, the slow-active suspension and the semi-active suspension which have controllable stiffness, damping and body height are more appropriate to use. For many years, some control methodologies for controllable suspension systems have been developed along with the development of modern control theory, and two or more original control methods are integrated as a new control method. Today, for military or civilian off-road vehicles, the R&D of controllable suspension systems is ongoing.

  3. Adaptive sliding control of non-autonomous active suspension systems with time-varying loadings

    Chen, Po-Chang; Huang, An-Chyau

    2005-04-01

    An adaptive sliding controller is proposed in this paper for controlling a non-autonomous quarter-car suspension system with time-varying loadings. The bound of the car-body loading is assumed to be available. Then, the reference coordinate is placed at the static position under the nominal loading so that the system dynamic equation is derived. Due to spring nonlinearities, the system property becomes asymmetric after coordinate transformation. Besides, in practical cases, system parameters are not easy to be obtained precisely for controller design. Therefore, in this paper, system uncertainties are lumped into two unknown time-varying functions. Since the variation bound of one of the unknown functions is not available, conventional adaptive schemes and robust designs are not applicable. To deal with this problem, the function approximation technique is employed to represent the unknown function as a finite combination of basis functions. The Lyapunov direct method can thus be used to find adaptive laws for updating coefficients in the approximating series and to prove stability of the closed-loop system. Since the position and velocity measurements of the unsprung mass are lumped into the unknown function, there is no need to install sensors on the axle and wheel assembly in the actual implementation. Simulation results are presented to show the performance of the proposed strategy.

  4. Spontaneous Circulation of Confined Active Suspensions

    Woodhouse, Francis G.; Goldstein, Raymond E

    2012-01-01

    Many active fluid systems encountered in biology are set in total geometric confinement. Cytoplasmic streaming in plant cells is a prominent and ubiquitous example, in which cargo-carrying molecular motors move along polymer filaments and generate coherent cell-scale flow. When filaments are not fixed to the cell periphery, a situation found both in vivo and in vitro, we observe that the basic dynamics of streaming are closely related to those of a non-motile stresslet suspension. Under this ...

  5. Mixing in suspensions of active particles

    Pushkin, Dmitri O.; Yeomans, Julia M.

    2014-03-01

    Microscopic active particles self-propelling in the surrounding fluid create flows that eventually lead to emergence of non-equilibrium states with long-ranged fluctuations. One of the technologically important consequences of these fluctuations is enhanced mixing of the surrounding fluid. It is also critical for understanding the ecology of a particular type of biological active systems, bacterial suspension, as the enhanced mixing strongly alters the fluxes of nutrients. We consider the theoretical foundations of fluid mixing enhancement in dilute suspensions of active force-free swimmers. We describe the impediments to fluid mixing imposed by the physical nature of fluid flows created by swimmers, and different ways of overcoming them. We show that fluid mixing in 3D suspensions of force-free (dipolar) swimmers is dominated by the effect of curvature of their trajectories, and obtain an exact analytical expression for the corresponding effective diffusion coefficient. Our results highlight limitations of alternative ``effective temperature'' approaches and may serve as a quantitative tool for designing technological applications.

  6. 49 CFR 570.61 - Suspension system.

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Suspension system. 570.61 Section 570.61 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... 10,000 Pounds § 570.61 Suspension system. (a) Suspension condition. Ball joint seals shall not be...

  7. 49 CFR 570.8 - Suspension systems.

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Suspension systems. 570.8 Section 570.8 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... Pounds or Less § 570.8 Suspension systems. (a) Suspension condition. Ball joint seals shall not be cut...

  8. Vibration Reduction System Using Magnetic Suspension Technology

    Spychała Jarosław

    2015-01-01

    Full Text Available The article presents considerations concerning the construction of vibration reduction system using magnetic suspension technology. Presents the results of simulation, numerical and experimental the bearingless electric motor, for which successfully used this type of solution. Positive results of research and testing have become the basis for the development of the concept of building this type of active vibration reduction system , at the same time acting as a support for a technical object, which is a jet engine. Bearing failures are manifested by loss or distortion of their mass, which leads to a total destruction of the roller bearing, and thus reflected in the security. The article presents the concept of building active magnetic suspension to eliminate the bearing system of classical rolling bearing and replace it with magnetic bearing.

  9. Spontaneous circulation of confined active suspensions.

    Woodhouse, Francis G; Goldstein, Raymond E

    2012-10-19

    Many active fluid systems encountered in biology are set in total geometric confinement. Cytoplasmic streaming in plant cells is a prominent and ubiquitous example, in which cargo-carrying molecular motors move along polymer filaments and generate coherent cell-scale flow. When filaments are not fixed to the cell periphery, a situation found both in vivo and in vitro, we observe that the basic dynamics of streaming are closely related to those of a nonmotile stresslet suspension. Under this model, it is demonstrated that confinement makes possible a stable circulating state; a linear stability analysis reveals an activity threshold for spontaneous autocirculation. Numerical analysis of the longtime behavior reveals a phenomenon akin to defect separation in nematic liquid crystals and a high-activity bifurcation to an oscillatory regime. PMID:23215137

  10. Introducing dual suspension system in road vehicles

    The main objective of suspension system is to reduce the motions of the vehicle body with respect to road disturbances. The conventional suspension systems in road vehicles use passive elements such as springs and dampers to suppress the vibrations induced by the irregularities in the road. But these conventional suspension systems can suppress vibrations to a certain limit. This paper presents a novel idea to improve the ride quality of roads vehicles without compromising vehicles stability. The paper proposes the use of primary and secondary suspension to suppress the vibrations more effectively. (author)

  11. Design and test of a novel magnetic lead screw for active suspension system in a vehicle

    Berg, Nick Ilsø; Holm, Rasmus Koldborg; Rasmussen, Peter Omand

    2014-01-01

    between lead and equivalent mass. Additionally using a Bode diagram, the frequency response of the hydraulic standard damper and various configurations of the MLS active damper are compared. The designed prototype is constructed and various tests are performed, leading to full efficiency map for the...

  12. 49 CFR 238.227 - Suspension system.

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Suspension system. 238.227 Section 238.227 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Equipment § 238.227 Suspension system. On or after November 8, 1999— (a) All passenger equipment...

  13. Magnetic suspension and balance systems (MSBSs)

    Britcher, Colin P.; Kilgore, Robert A.

    1987-01-01

    The problems of wind tunnel testing are outlined, with attention given to the problems caused by mechanical support systems, such as support interference, dynamic-testing restrictions, and low productivity. The basic principles of magnetic suspension are highlighted, along with the history of magnetic suspension and balance systems. Roll control, size limitations, high angle of attack, reliability, position sensing, and calibration are discussed among the problems and limitations of the existing magnetic suspension and balance systems. Examples of the existing systems are presented, and design studies for future systems are outlined. Problems specific to large-scale magnetic suspension and balance systems, such as high model loads, requirements for high-power electromagnets, high-capacity power supplies, highly sophisticated control systems and position sensors, and high costs are assessed.

  14. Experimental Evaluation of Mountain Bike Suspension Systems

    J. Titlestad

    2003-01-01

    Full Text Available A significant distinction between competitive mountain bikes is whether they have a suspension system. Research studies indicate that a suspension system gives advantages, but it is difficult to quantify the benefits because they depend on so many variables, including the physiology and psychology of the cyclist, the roughness of the track and the design of the suspension system. A laboratory based test rig has been built that allows the number of variables in the system to be reduced and test conditions to be controlled. The test rig simulates regular impacts of the rear wheel with bumps in a rolling road. The physiological variables of oxygen consumption and heart rate were measured, together with speeds and forces at various points in the system. Physiological and mechanical test results both confirm a significant benefit in using a suspension system on the simulated rough track, with oxygen consumption reduced by around 30 % and power transmitted through the pedals reduced by 30 % to 60 %.

  15. Suspensions

    Braccini, Stefano

    2000-06-01

    Special suspension systems are used in gravitational wave detectors to reduce the transmission of seismic vibrations to test masses by many orders of magnitude. In ground-based interferometric antennas, this allows to detect gravitational signals even below a few tens of Hz, where seismic vibrations are very strong. The state of the art on this topic is presented. .

  16. Tank Riser Suspension System Conceptual Design

    A team of engineers from High Level Waste (HLW), the Savannah River Technology Center (SRTC), and Project Engineering and Construction Division (PE and CD) explored ways of more effectively utilizing the HLW tank's risers during waste removal and closure activities. Currently, some of the risers are being used to store failed and contaminated equipment. To make those risers available for tank operation, failed equipment must be moved out of the tank and relocated or disposed of appropriately. Disposing of contaminated equipment is a time consuming and expensive process. This report describes the Tank Riser Suspension System (TRSS). It will allow failed equipment to be stored inside of the tank while making riser space available for other tank process equipment. In addition, the TRSS will permit disposing of failed equipment in the tank as part of tank closure activities

  17. Diffusion in active suspension of microswimmers

    Climent, Eric; Delmotte, Blaise; Plouraboue, Franck; Keaveny, Eric; Martin, Matthieu; Rafai, Salima; Peyla, Philippe; Bertin, Eric; IMFT Team; IC Team; LiPhy Team

    2015-11-01

    The presence of microswimmers in a fluid generates flow agitation due to multi-body hydrodynamic interactions. This agitation of the fluid leads to random trajectories of passive tracers particles and the swimmers themselves, and from a macroscopic point view, it can be interpreted as a diffusive mechanism. By means of experiments (videomicroscopy of suspensions of chlamydomonas reinhardtii)and numerical simulations (Stokesian fluid populated with squirmers), we investigate the evolution of the effective diffusion coefficient when the volumetric concentration of the active suspension varies. By comparing the experimental and numerical results, we quantify the role of active swimming on the measured diffusion and identify the physical mechanisms that lead to diffusion enhancement. Our results aim to provide a better understanding of how swimming organisms affect micron-scale transport in the environment.

  18. Diffusion of passive particles in active suspensions

    Mussler, Matthias; Rafai, Salima; John, Thomas; Peyla, Philippe; Wagner, Christian

    2013-11-01

    We study how an active suspension consisting of a definite volume fraction of the microswimmer Chlamydomonas Reinhardtii modifies the Brownian movement of small to medium size microspheres. We present measurements and simulations of trajectories of microspheres with a diameter of 20 μm in suspensions of Chlamydomonas Reinhardtii, a so called ``puller,'' and show that the mean squared displacement of such trajectories consist of parabolic and a linear part. The linear part is due to the hydrodynamic noise of the microswimmers while the parabolic part is a consequence of directed motion events that occur randomly, when a microsphere is transported by a microswimmer on a timescale that is in higher order of magnitude than the Brownian like hydrodynamic interaction. In addition, we theoretically describe this effect with a dimensional analysis that takes the force dipole model used to describe ``puller'' like Chlamydomonas Reinhardtii into account.

  19. Development of an Air Pneumatic Suspension System for Transtibial Prostheses

    Gholamhossein Pirouzi

    2014-09-01

    Full Text Available The suspension system and socket fitting of artificial limbs have major roles and vital effects on the comfort, mobility, and satisfaction of amputees. This paper introduces a new pneumatic suspension system that overcomes the drawbacks of current suspension systems in donning and doffing, change in volume during daily activities, and pressure distribution in the socket-stump interface. An air pneumatic suspension system (APSS for total-contact sockets was designed and developed. Pistoning and pressure distribution in the socket-stump interface were tested for the new APSS. More than 95% of the area between each prosthetic socket and liner was measured using a Tekscan F-Scan pressure measurement which has developed matrix-based pressure sensing systems. The variance in pressure around the stump was 8.76 kPa. APSS exhibits less pressure concentration around the stump, improved pressure distribution, easy donning and doffing, adjustability to remain fitted to the socket during daily activities, and more adaptability to the changes in stump volume. The volume changes were adjusted by utility of air pressure sensor. The vertical displacement point and reliability of suspension were assessed using a photographic method. The optimum pressure in every level of loading weight was 55 kPa, and the maximum displacement was 6 mm when 90 N of weight was loaded.

  20. Energy Conservation Analysis and Control of Hybrid Active Semiactive Suspension with Three Regulating Damping Levels

    Long Chen; Dehua Shi; Ruochen Wang; Huawei Zhou

    2016-01-01

    Active suspension has not been popularized for high energy consumption. To address this issue, this paper introduces the concept of a new kind of suspension. The linear motor is considered to be integrated into an adjustable shock absorber to form the hybrid active semiactive suspension (HASAS). To realize the superiority of HASAS, its energy consumption and regeneration mechanisms are revealed. And the system controller which is composed of linear quadratic regulator (LQR) controller, mode d...

  1. Active following fuzzy output feedback sliding mode control of real-vehicle semi-active suspensions

    Liu, H.; Nonami, K.; Hagiwara, T.

    2008-07-01

    Many semi-active suspension systems have been investigated in various literatures in order to achieve lower energy consumption and as good performance as full-active suspension systems. Full-active suspension systems can achieve a good ride quality by actuators; however, their implementation equipments are expensive. The full-active suspensions are perfect from the point of view of control; hence, semi-active control laws with performance similar to full-active controls have attracted the engineering community for their ease and lower cost of implementation. This paper presents a new active following fuzzy output feedback sliding mode control for a real-vehicle semi-active suspension system. The performance of the proposed controller has been verified by comparing it with passive control and also with the full-active target semi-active approximation control method. In the experiment, it was shown that the proposed method has the effectiveness in stabilizing heave, roll and pitch movement of the car body.

  2. Mirror suspension system for the TAMA SAS

    Several R and D programmes are ongoing to develop the next generation of interferometric gravitational wave detectors providing the superior sensitivity desired for refined astronomical observations. In order to obtain a wide observation band at low frequencies, the optics need to be isolated from the seismic noise. The TAMA SAS (seismic attenuation system) has been developed within an international collaboration between TAMA, LIGO, and some European institutes, with the main objective of achieving sufficient low-frequency seismic attenuation (-180 dB at 10 HZ). The system suppresses seismic noise well below the other noise levels starting at very low frequencies above 10 Hz. It also includes an active inertial damping system to decrease the residual motion of the optics enough to allow a stable operation of the interferometer. The TAMA SAS also comprises a sophisticated mirror suspension subsystem (SUS). The SUS provides support for the optics and vibration isolation complementing the SAS performance. The SUS is equipped with a totally passive magnetic damper to suppress internal resonances without degrading the thermal noise performance. In this paper we discuss the SUS details and present prototype results

  3. Denitrifying activity of activated sludge in suspension and in biofilm

    Cortez, Susana; Teixeira, P.; Oliveira, Rosário; Mota, M.

    2008-01-01

    A method based on measuring substrate depletion rate was developed to evaluate the denitrifying activity of activated sludge in suspension and in biofilm form in anoxic serum flasks. The adapted activated sludge inoculum was grown as biofilm in an anoxic rotating biological contactor (RBC). Acetate was used as external carbon source to obtain a carbon to nitrogen ratio (C/N) of 2. The results showed that the specific activity of cells in biofilm form was higher than in planktonic for...

  4. Active Control of Shear Thickening in Suspensions

    Lin, Neil Y C; Cates, Michael E; Sun, Jin; Cohen, Itai

    2016-01-01

    Shear thickening, an increase of viscosity with shear rate, is a ubiquitous phenomena in suspended materials that has implications for broad technological applications. Controlling this thickening behavior remains a major challenge and has led to empirical strategies ranging from altering the particle surfaces and shape to modifying the solvent properties. However, none of these methods allow for active control of flow properties during shear itself. Here, we demonstrate that by strategic imposition of a high-frequency and low-amplitude shear perturbation orthogonal to the primary shearing flow, we can largely eradicate shear thickening. The orthogonal shear effectively becomes a regulator for controlling thickening in the suspension, allowing the viscosity to be reduced by up to two decades on demand. In a separate setup, we show that such effects can be induced by simply agitating the sample transversely to the primary shear direction. Overall, the ability of in situ manipulation of shear thickening paves a...

  5. Construction and Control of an active suspension for a field sprayer boom

    Nielsen, Henrik Skovsgaard; Sørensen, Paul Haase

    1998-01-01

    The main purpose in the study of boom suspension is to investigate the possibility of using an active suspension instead of the traditional passive system. In addition to the improved spraying result, an active system would make the operator's task much easier. The project compares the possible...... combines a hydraulic actuator and a spring. A closed loop lead compensator including a set of distance transducers has improved the performance significantly. The active system has been simulated on a constructed srface....

  6. Optimization of Semi-active Seat Suspension with Magnetorheological Damper

    Segla, Stefan; Kajaste, J.; Keski-Honkola, P.

    The paper deals with modeling, control and optimization of semiactive seat suspension with pneumatic spring and magnetorheological damper. The main focus is on isolating vertical excitation from the cabin of a bucket-wheel excavator in order to protect the excavator driver against harmful vibration. Three different control algorithms are used to determine the desired semi-active damping force: skyhook control, balance control and combination of balance and skyhook controls. The dynamic behavior of the semi-active system is optimized using genetic algorithms. As the objective function the effective value of the seat (sprung mass) acceleration is used.

  7. Proportional-integral-derivative control of nonlinear half-car electro-hydraulic suspension systems

    John E.D.EKORU; Jimoh O.PEDRO

    2013-01-01

    This paper presents the development of a proportional-integral-derivative (PID)-based control method for application to active vehicle suspension systems (AVSS).This method uses an inner PID hydraulic actuator force control loop,in combination with an outer PID suspension travel control loop,to control a nonlinear half-car AVSS.Robustness to model uncertainty in the form of variation in suspension damping is tested,comparing performance of the AVSS with a passive vehicle suspension system (PVSS),with similar model parameters.Spectral analysis of suspension system model output data,obtained by performing a road input disturbance frequency sweep,provides frequency response plots for both nonlinear vehicle suspension systems and time domain vehicle responses to a sinusoidal road input disturbance on a smooth road.The results show the greater robustness of the AVSS over the PVSS to parametric uncertainty in the frequency and time domains.

  8. Simulation and experiment study of pneumatic active suspension system with fuzzy controller%空气主动悬架模糊控制仿真与实验研究

    潘公宇; 陈立付; 聂秀伟; 张庆庆

    2011-01-01

    建立了1/4车体二自由度的空气主动悬架模型,设计了用于该主动空气悬架的模糊控制器,应用Matlab/Simulink控制系统仿真软件,对1/4汽车空气主动悬架模型进行计算机仿真.仿真结果表明具有此模糊控制器的空气主动悬架在提高车辆乘坐的舒适性和操纵的稳定性方面明显优于空气被动悬架.在此基础上,设计了空气主动悬架台架实验,进行了空气被动悬架与空气主动悬架的台架对比实验.由实验结果可以看出,与空气被动悬架相比,空气主动悬架能有效改善车辆性能,与仿真研究结果具有一致性.%The two-degree of freedom pneumatic active suspension model for a quarter of vehicle is built up,then the designing way of automobile pneumatic active suspension with fuzzy controller is introduced in fuzzy system.The comparison study through simulation by using Matlab/Simulink shows that the performance of pneumatic active suspension with fuzzy controller is better than that of pneumatic passive suspension. Meanwhile ,contrastive experiment of pneumatic active snspension and pneumatic passive suspension has carried out. The results show that the pneumatic active suspension improves the characteristics of the dynamic capability. It is identical to the simulation result.

  9. A nonlinear kinematic and dynamic modeling of Macpherson suspension systems with a magneto-rheological damper

    Dutta, Saikat; Choi, Seung-Bok

    2016-03-01

    It is well known that Macpherson strut suspension systems are widely used in light and medium weight vehicles. The performance of these suspension systems can be enriched by incorporating magneto-rheological (MR) dampers and an appropriate dynamic model is required in order to find out the ride comfort and other performances properly in the sense of practical environment conditions. Therefore, in this work the kinematic and dynamic modeling of Macpherson strut suspension system with MR damper is presented and its responses are evaluated. The governing equations are formulated using the kinematic properties of the suspension system and adopting Lagrange’s equation. In the formulation of the model, both the rotation of the wheel assembly and the lateral stiffness of the tire are considered to represent the nonlinear characteristic of Macpherson type suspension system. The formulated mathematical model is then compared with equivalent conventional quarter car suspension model and the different dynamic responses such as the displacement of the sprung mass are compared to emphasize the effectiveness of the proposed model. Additionally, in this work the important kinematic properties of suspension system such as camber angle, king-pin angle and track width alteration, which cannot be obtained from conventional quarter car suspension model, are evaluated in time and frequency domains. Finally, vibration control responses of the proposed suspension system are presented in time and frequency domains which are achieved from the semi-active sky-hook controller.

  10. A multibody systems approach to suspension modelling and simulation using suspension derivatives

    This paper describes the initial phase of a study where the modelling of the suspension system has been adapted for use with computer simulations of vehicle handling during the early concept stages of vehicle design. This work has been carried out using an industry standard multibody systems analysis program known as ADAMS (Automatic Dynamic Analysis of Mechanical Systems). Work has been carried out using measured characteristics from a McPherson strut suspension system installed in a laboratory based suspension rig. A traditional approach based on modelling the suspension is considerable detail is compared with a method that considers the wheel movement relative to the vehicle body to be controlled by mathematical relationships. Using this method the wheel centre can be constrained by follow a path in three-dimensional space and the orientation of the wheel is defined as a function of the wheel position. At this stage the gradients of curves, obtained at the origin, from plots of suspension characteristics such as chamber angle against bump movement are used to define the change in orientation. These gradients are sometimes referred to as suspension derivatives. The paper concludes by discussing the advantages of a model based on parameters rather than the modelling of physical components and the further work needed to develop a similar approach for the modelling of suspension compliance. (Author)

  11. Magnetic suspension and balance system study

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.

    1984-01-01

    A compact design for a superconducting magnetic suspension and balance system is developed for a 8 ft. x 8 ft. transonic wind tunnel. The main features of the design are: a compact superconducting solenoid in the suspended airplane model; permanent magnet wings; one common liquid helium dewar for all superconducting coils; efficient new race track coils for roll torques; use of established 11 kA cryostable AC conductor; acceptable AC losses during 10 Hz control even with all steel structure; and a 560 liter/hour helium liquefier. Considerable design simplicity, reduced magnet weights, and reduced heat leak results from using one common dewar which eliminates most heavy steel structure between coils and the suspended model. Operational availability is thought to approach 100% for such magnet systems. The weight and cost of the magnet system is approximately one-third that of previous less compact designs.

  12. A hybrid clustering based fuzzy structure for vibration control - Part 2: An application to semi-active vehicle seat-suspension system

    Nguyen, Sy Dzung; Nguyen, Quoc Hung; Choi, Seung-Bok

    2015-05-01

    This work presents a novel neuro-fuzzy controller (NFC) for car-driver's seat-suspension system featuring magnetorheological (MR) dampers. The NFC is built based on the algorithm for building adaptive neuro-fuzzy inference systems (ANFISs) named B-ANFIS, which has been developed in Part 1, and fuzzy logic inference systems (FISs). In order to create the NFC, the following steps are performed. Firstly, a control strategy based on a ride-comfort-oriented tendency (RCOT) is established. Subsequently, optimal FISs are built based on a genetic algorithm (GA) to estimate the desired damping force that satisfies the RCOT corresponding to the road status at each time. The B-ANFIS is then used to build ANFISs for inverse dynamic models of the suspension system (I-ANFIS). Based on the FISs, the desired force values are calculated according to the status of road at each time. The corresponding exciting current value to be applied to the MR damper is then determined by the I-ANFIS. In order to validate the effectiveness of the developed neuro-fuzzy controller, control performances of the seat-suspension systems featuring MR dampers are evaluated under different road conditions. In addition, a comparative work between conventional skyhook controller and the proposed NFC is undertaken in order to demonstrate superior control performances of the proposed methodology.

  13. 车辆主动油气悬架系统分层控制策略的研究%A Study on the Hierarchical Control Strategy for Active Hydro-pneumatic Suspension System of Vehicles

    冯金芝; 谭辉; 郑松林; 喻凡

    2013-01-01

    基于虚拟样机技术构建了工程车主动油气悬架控制系统的数字开发平台.针对工程车行驶路况的不确定性、部分参数的时变性和油气悬架系统的强非线性,提出了有限带宽主动油气悬架系统分层控制策略,并设计了基于遗传算法的模糊PID上层力控制器和基于模型的下层电压控制器.将该控制算法集成到悬架控制系统数字开发平台中进行联合仿真.结果表明,所研制的有限带宽主动悬架分层控制器可显著改善车辆的行驶平顺性.%A digital development platform for the active hydro-pneumatic suspension control.system of a construction vehicle is built based on virtual prototyping technology.In view of the uncertainty of road conditions the construction vehicle runs on,the time-varying feature of some parameters and the high nonlinearity of hydro-pneumatic suspension system,a hierarchical control strategy for active hydro-pneumatic suspension system with finite bandwidth is proposed,and the genetic algorithm-based fuzzy-PID force controller in upper layer and the modelbased voltage controller in bottom layer are designed.The control algorithms developed are integrated into the digital development platform for suspension control system and a co-simulation is conducted.The results show that the hierarchical controllers developed for active suspension with finite bandwidth can significantly improve the ride comfort of vehicles.

  14. Study of Japanese electrodynamic-suspension maglev systems

    He, J.L.; Rote, D.M.; Coffey, H.T. [Argonne National Lab., IL (United States). Center for Transportation Research

    1994-04-01

    This report presents the results of a study of the Japanese MLU magnetic-levitation (maglev) system. The development of the MLU system is reviewed, and the dynamic circuit model then is introduced and applied to the figure-eight-shaped null-flux coil suspension system. Three different types of figure-eight-shaped null-flux suspension systems are discussed in detail: (1) the figure-eight-shaped null-flux coil suspension system without cross-connection; (2) the combined suspension and guidance system; and (3) the combined propulsion, levitation, and guidance system. The electrodynamic-suspension maglev systems developed in Japan seem to be very promising and could result in a commercial application in the near future.

  15. Anomalous velocity distributions in active Brownian suspensions

    Fiege, Andrea; Vollmayr-Lee, Benjamin; Zippelius, Annette

    2013-01-01

    Large scale simulations and analytical theory have been combined to obtain the non-equilibrium velocity distribution, $f(v)$, of randomly accelerated particles in suspension. The simulations are based on an event-driven algorithm, generalised to include friction. They reveal strongly anomalous but largely universal distributions which are independent of volume fraction and collision processes, which suggests a one-particle model should capture all the essential features. We have formulated th...

  16. Active microrheology of Brownian suspensions via Accelerated Stokesian Dynamics simulations

    Chu, Henry; Su, Yu; Gu, Kevin; Hoh, Nicholas; Zia, Roseanna

    2015-11-01

    The non-equilibrium rheological response of colloidal suspensions is studied via active microrheology utilizing Accelerated Stokesian Dynamics simulations. In our recent work, we derived the theory for micro-diffusivity and suspension stress in dilute suspensions of hydrodynamically interacting colloids. This work revealed that force-induced diffusion is anisotropic, with qualitative differences between diffusion along the line of the external force and that transverse to it, and connected these effects to the role of hydrodynamic, interparticle, and Brownian forces. This work also revealed that these forces play a similar qualitative role in the anisotropy of the stress and in the evolution of the non-equilibrium osmotic pressure. Here, we show that theoretical predictions hold for suspensions ranging from dilute to near maximum packing, and for a range of flow strengths from near-equilibrium to the pure-hydrodynamic limit.

  17. Robust Active Suspension Design Subject to Vehicle Inertial Parameter Variations

    Hai-Ping Du; Nong Zhang

    2010-01-01

    This paper presents an approach in designing a robust controller for vehicle suspensions considering changes in vehicle inertial properties. A four-degree-of-freedom half-car model with active suspension is studied in this paper, and three main performance requirements are considered. Among these requirements, the ride comfort performance is optimized by minimizing the H∞ norm of the transfer function from the road disturbance to the sprung mass acceleration, while the road holding performance and the suspension deflection limitation are guaranteed by constraining the generalized H2 (GH2) norms of the transfer functions from the road disturbance to the dynamic tyre load and the suspension deflection to be less than their hard limits, respectively. At the same time, the controller saturation problem is considered by constraining its peak response output to be less than a given limit using the GH2 norm as well. By solving the finite number of linear matrix inequalities (LMIs) with the minimization optimization procedure, the controller gains, which are dependent on the time-varying inertial parameters, can be obtained. Numerical simulations on both frequency and bump responses show that the designed parameter-dependent controller can achieve better active suspension performance compared with the passive suspension in spite of the variations of inertial parameters.

  18. Magnetic suspension and balance system advanced study

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.

    1985-01-01

    An improved compact design for a superconducting magnetic suspension and balance system for an 8 ft. x 8 ft. transonic wind tunnel is developed. The original design of an MSBS in NASA Cr-3802 utilized 14 external superconductive coils and a superconductive solenoid in the airplane test model suspended in a wind tunnel. The improvements are in the following areas: test model solenoid options, dynamic force limits on the model, magnet cooling options, structure and cryogenic designs, power supply specifications, and cost and performance evaluations. The improvements are: MSBS cost reduction of 28%, weight; reduction of 43%, magnet system ampere-meter reduction of 38%, helium liquifier capacity reduction by 33%, magnet system stored energy reduction by 55%, AC loss to liquid helium reduced by 76%, system power supply reduced by 68%, test coil pole strength increased by 19%, wing magnetization increased by 40%, and control frequency limit increased by 200% from 10 Hz to 30 Hz. The improvements are due to: magnetic holmium coil forms in the test model, better rare earth permanent magnets in the wings, fiberglass-epoxy structure replacing stainless steel, better coil configuration, and new saddle roll coil design.

  19. Robust H∞ control of active vehicle suspension under non-stationary running

    Guo, Li-Xin; Zhang, Li-Ping

    2012-12-01

    Due to complexity of the controlled objects, the selection of control strategies and algorithms in vehicle control system designs is an important task. Moreover, the control problem of automobile active suspensions has been become one of the important relevant investigations due to the constrained peculiarity and parameter uncertainty of mathematical models. In this study, after establishing the non-stationary road surface excitation model, a study on the active suspension control for non-stationary running condition was conducted using robust H∞ control and linear matrix inequality optimization. The dynamic equation of a two-degree-of-freedom quarter car model with parameter uncertainty was derived. The H∞ state feedback control strategy with time-domain hard constraints was proposed, and then was used to design the active suspension control system of the quarter car model. Time-domain analysis and parameter robustness analysis were carried out to evaluate the proposed controller stability. Simulation results show that the proposed control strategy has high systemic stability on the condition of non-stationary running and parameter uncertainty (including suspension mass, suspension stiffness and tire stiffness). The proposed control strategy can achieve a promising improvement on ride comfort and satisfy the requirements of dynamic suspension deflection, dynamic tire loads and required control forces within given constraints, as well as non-stationary running condition.

  20. Anomalous velocity distributions in active Brownian suspensions.

    Fiege, Andrea; Vollmayr-Lee, Benjamin; Zippelius, Annette

    2013-08-01

    Large-scale simulations and analytical theory have been combined to obtain the nonequilibrium velocity distribution, f(v), of randomly accelerated particles in suspension. The simulations are based on an event-driven algorithm, generalized to include friction. They reveal strongly anomalous but largely universal distributions, which are independent of volume fraction and collision processes, which suggests a one-particle model should capture all the essential features. We have formulated this one-particle model and solved it analytically in the limit of strong damping, where we find that f(v) decays as 1/v for multiple decades, eventually crossing over to a Gaussian decay for the largest velocities. Many particle simulations and numerical solution of the one-particle model agree for all values of the damping. PMID:24032806

  1. 31 CFR 903.2 - Suspension of collection activity.

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Suspension of collection activity. 903.2 Section 903.2 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... suspend collection activity during the time required for consideration of the debtor's request for...

  2. Active aerodynamic stabilisation of long suspension bridges

    Nissen, Henrik Ditlev; Sørensen, Paul Haase; Jannerup, Ole Erik

    2004-01-01

    use of control analysis and design techniques, a linear model of the structural and aerodynamic motion around equilibriun is developed. The model is validated through comparison with finite element calculations and wind tunnel experimental data on the Great Belt East Bridge in Denmark. The developed......The paper describes the addition of actively controlled appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suppension bridges. A novel approach using control systems methods for the analysis of dynamic stability is presented. In order to make...... active control scheme is local in that the flap control signal at a given longitudinal position along the bridge only depends on local motion measurements. The analysis makes use of the Nyquist stability criteria and an anlysis of the sensitivity function for stability analysis. The analysis shows that...

  3. Performance analysis of a semiactive suspension system with particle swarm optimization and fuzzy logic control.

    Qazi, Abroon Jamal; de Silva, Clarence W; Khan, Afzal; Khan, Muhammad Tahir

    2014-01-01

    This paper uses a quarter model of an automobile having passive and semiactive suspension systems to develop a scheme for an optimal suspension controller. Semi-active suspension is preferred over passive and active suspensions with regard to optimum performance within the constraints of weight and operational cost. A fuzzy logic controller is incorporated into the semi-active suspension system. It is able to handle nonlinearities through the use of heuristic rules. Particle swarm optimization (PSO) is applied to determine the optimal gain parameters for the fuzzy logic controller, while maintaining within the normalized ranges of the controller inputs and output. The performance of resulting optimized system is compared with different systems that use various control algorithms, including a conventional passive system, choice options of feedback signals, and damping coefficient limits. Also, the optimized semi-active suspension system is evaluated for its performance in relation to variation in payload. Furthermore, the systems are compared with respect to the attributes of road handling and ride comfort. In all the simulation studies it is found that the optimized fuzzy logic controller surpasses the other types of control. PMID:24574868

  4. Study on Dynamic Behaviour of Wishbone Suspension System

    Kamal, M.; Rahman, M. M.

    2012-09-01

    This paper presents the characteristic model of the wishbone suspension system using the quarter car model approach. Suspension system in an automobile provides vehicle control and passenger comfort by providing isolation from road disturbances. This makes it essential that the detailed behavior of suspension should be known to optimize the performance. A kinetic study is performed using multi body system (MBS) analysis. The dirt road profile is considered as an applied loading. The spring constant, damping coefficient and sprung mass are studied on the performance of the suspension system. It can be observed that the spring constant is inversely related with time required to return to initial position and the amount of deformations. The damping ratio affects the suppression of spring oscillations, beyond a certain limit damping ration has the negligible effect. Sprung mass effected the equilibrium position of the suspension system with a small effect on its oscillation behavior. It is shown that the spring constant, damping ratio and sprung mass are significant parameters to design the suspension system. This study is essential for complete understanding of working of the suspension system and a future study with real geometries.

  5. Study on Dynamic Behaviour of Wishbone Suspension System

    This paper presents the characteristic model of the wishbone suspension system using the quarter car model approach. Suspension system in an automobile provides vehicle control and passenger comfort by providing isolation from road disturbances. This makes it essential that the detailed behavior of suspension should be known to optimize the performance. A kinetic study is performed using multi body system (MBS) analysis. The dirt road profile is considered as an applied loading. The spring constant, damping coefficient and sprung mass are studied on the performance of the suspension system. It can be observed that the spring constant is inversely related with time required to return to initial position and the amount of deformations. The damping ratio affects the suppression of spring oscillations, beyond a certain limit damping ration has the negligible effect. Sprung mass effected the equilibrium position of the suspension system with a small effect on its oscillation behavior. It is shown that the spring constant, damping ratio and sprung mass are significant parameters to design the suspension system. This study is essential for complete understanding of working of the suspension system and a future study with real geometries.

  6. Inertia Wheel on Low-Noise Active Magnetic Suspension

    Carabelli, S.; Genta, G.; Silvagni, M.; Tonoli, A.

    2002-01-01

    Magnetic bearings are particularly suited for space applications for a number of reasons: - they are ideally suited for vacuum applications; - the lack of lubrication and wear enhances the reliability and guaranties a long maintenance-free operation - the low drag torque decreases power consumption and reduces the torque exerted on the stator of the machine. - the possibility of insulating actively the spacecraft from the excitation due to unbalance of the rotating system In the case of reaction wheels, a well designed magnetic suspension allows high speed operation with a very low power consumption and vibration level. Conversely, microgravity (and possibly vacuum) operation is an advantage for magnetic bearings. The absence of static forces allows to operate with low current levels, thus reducing electrical noise and allowing to reach even lower vibration levels than in Earth applications of magnetic bearings. Active magnetic bearings (AMB) allow to adapt the working characteristics of the system to the operating needs: it is possible to use the actuators to lock the system during launch (absence of grabbers) and to stiffen the suspension when the spacecraft is accelerated (impulsive phases), while working in conditions optimised for microgravity when this is needed. Magnetic suspension systems designed for microgravity environment cannot be correctly tested on the ground. Testing in ground conditions results in the need of grossly overdesigning the levitation device; furthermore, in some cases ground testing is completely impossible, if not by introducing devices which compensate for the Earth gravitational field. If the compensation for the gravitational force is supplied by the same actuators used for microgravity operation, the actuators and the power amplifiers must be overdesigned and in some cases the suspension can be altogether impossible. They work in conditions which are much different from nominal ones and, above all, it is impossible to reach the

  7. Design and vibration control of military vehicle suspension system using magnetorheological damper and disc spring

    This paper proposes a new type of magnetorheological (MR) fluid based suspension system and applies it to military vehicles for vibration control. The suspension system consists of a gas spring, a MR damper and a safety passive damper (disc spring). Firstly, a dynamic model of the MR damper is derived by considering the pressure drop due to the viscosity and the yield stress of the MR fluid. A dynamic model of the disc spring is then established for its evaluation as a safety damper with respect to load and pressure. Secondly, a full military vehicle is adopted for the integration of the MR suspension system. A skyhook controller associated with a semi-active actuating condition is then designed to reduce the imposed vibration. In order to demonstrate the effectiveness of the proposed MR suspension system, a computer simulation is undertaken showing the vibration control performance of such properties as vertical displacement and pitch angle, evaluated for a bumpy road profile. (paper)

  8. 基于键合图理论的主动油气悬架仿真研究%Simulation of Active Hydro-pneumatic Suspension System Based on Bond Graph

    洪展鹏; 王丛岭

    2014-01-01

    The vibration model of 2 degrees of freedom 1/4 active hydro-pneumatic suspension (AHP) is built in this paper ,which is used to model the hydro-pneumatic suspension through bond graph(BG) .The equation of state of the hydro-pneumatic suspension with nonlinear characteristic is educed based on the BG model .The method reflects the superiority of bond graph in different energy coupling system .By use of the powerful computation ability of MATLAB ,this paper simulates the state equation through it .The active and passive hydro-pneumatic suspensions are compared ,the results show the AHP reduces body acceleration effectively and improve the ride performance .%基于2自由度1/4主动油气悬架的振动模型,建立了其对应的键合图模型。根据键合图模型详细推导了具有非线性特性的油气悬架状态方程,充分体现了键合图理论在分析不同能量域耦合系统中的优越性。利用MATLAB强大的计算能力,对状态方程进行仿真,对比了主动油气悬架与被动悬架的特性,结果表明主动控制的油气悬架有效减少了车身加速度,提高了行驶平顺性。

  9. Parameter identification of a full-car model for active suspension design

    D. Guidaa

    2010-06-01

    Full Text Available Purpose: A method for identifying parameters of a full-car model for active suspension designDesign/methodology/approach: The method is based on ERA/OKID identification procedure developed by Juang [1].Findings: Numerical results show a good agreement with real system parameters.Research limitations/implications: Results show that this method works well only with a high signal-to-noise ratio.Practical implications: This method can be used as an aid to active suspension design.Originality/value: This procedure has been tested on the full-car model of suspension system in two cases: a full-state measurements; b not full-state measurements.

  10. Torsional asymmetry in suspension bridge systems

    Malík, Josef

    2015-01-01

    Roč. 60, č. 6 (2015), s. 677-701. ISSN 0862-7940 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : suspension bridge * Hamilton principle * vertical and torsional oscillation * uniqueness * existence Subject RIV: BA - General Mathematics Impact factor: 0.400, year: 2014 http://link.springer.com/article/10.1007%2Fs10492-015-0117-3

  11. Modification of a Two Wheeler Suspension System using Fea

    Koneti.Manikanta

    2014-11-01

    Full Text Available A spring is defined as an elastic body, whose function is to compress when loaded and to recover its original shape when the load is removed. A spring is a flexible element used to exert a force or a torque and, at the same time, to store energy. The force can be a linear push or pull, or it can be radial. In two wheelers we used to see helical suspension at the front and rear tyres on both sides. But the new model bikes are replacing the rear double suspension with the single heavy duty suspension. Our project deals with the design and modification of the suspension system and analyzing that can we replace one heavy duty spring in the place of double springs. For this we have conducted structural analysis by varying the spring material and keeping base material same. By seeing the results, Comparison is done for four materials to validate better material for suspension system by doing analysis on spring with help of ANSYS software for find out which material is best for the suspension system. And also we modified the actual model and also conducting the same analysis on it and validating that which model is better. The modeling done in Creo-5 and analysis is done Ansys package.

  12. Optimisation of Kinematics for Tracked Vehicle Hydro Gas Suspension System

    S. Sridhar

    2006-11-01

    Full Text Available The modern-day armoured fighting vehicles (AFVs are basically tracked vehicles equippedwith hydro gas suspensions, in lieu of conventional mechanical suspensions like torsion barand coil spring bogie suspensions. The uniqueness of hydro gas suspension is that it offersa nonlinear spring rate, which is very much required for the cross-country moveability of atracked vehicle. The AFVs have to negotiate different cross-country terrains like sandy, rocky,riverbed, etc. and the road irregularities provide enumerable problems during dynamic loadingsto the design of hydro gas suspension system. Optimising various design parameters demandsinnovative design methodologies to achieve better ride performance. Hence, a comprehensivekinematic analysis is needed. In this study, a methodology has been derived to optimise thekinematics of the suspension by reorienting the cylinder axis and optimising the loadtransferringleverage factor so that the side thrust on the cylinder is minimised to a greaterextent. The optimisation ultimately increases the life of the high-pressure and high-temperaturepiston seals, resulting in enhanced system life for better dependability.

  13. Energy Conservation Analysis and Control of Hybrid Active Semiactive Suspension with Three Regulating Damping Levels

    Long Chen

    2016-01-01

    Full Text Available Active suspension has not been popularized for high energy consumption. To address this issue, this paper introduces the concept of a new kind of suspension. The linear motor is considered to be integrated into an adjustable shock absorber to form the hybrid active semiactive suspension (HASAS. To realize the superiority of HASAS, its energy consumption and regeneration mechanisms are revealed. And the system controller which is composed of linear quadratic regulator (LQR controller, mode decision and switch controller, and the sliding mode control based thrust controller is developed. LQR controller is designed to maintain the suspension control objectives, while mode decision and switch controller decides the optimal damping level to tune motor thrust. The thrust controller ensures motor thrust tracking. An adjustable shock absorber with three regulating levels to be used in HASAS is trial produced and tested to obtain its working characteristics. Finally, simulation analysis is made with the experimental three damping characteristics. The impacts of adjustable damping on the motor force and energy consumption are investigated. Simulation results demonstrate the advantages of HASAS in energy conservation with various suspension control objectives. Even self-powered active control and energy regenerated to the power source can be realized.

  14. Adaptive super-twisting observer for estimation of random road excitation profile in automotive suspension systems.

    Rath, J J; Veluvolu, K C; Defoort, M

    2014-01-01

    The estimation of road excitation profile is important for evaluation of vehicle stability and vehicle suspension performance for autonomous vehicle control systems. In this work, the nonlinear dynamics of the active automotive system that is excited by the unknown road excitation profile are considered for modeling. To address the issue of estimation of road profile, we develop an adaptive supertwisting observer for state and unknown road profile estimation. Under Lipschitz conditions for the nonlinear functions, the convergence of the estimation error is proven. Simulation results with Ford Fiesta MK2 demonstrate the effectiveness of the proposed observer for state and unknown input estimation for nonlinear active suspension system. PMID:24683321

  15. Design of nonlinear passive suspension system using an evolutionary programming

    This paper proposes a methodology of finding out a set of optimal system parameters in the design of a nonlinear vehicle passive suspension system (PSS) using an evolutionary programming (EP). The difficulties for nonlinear PSS design arise due to the displacement limitation of the suspension and tire deflection, nonlinear characteristics of the system parameters, and the conflict demands for ride comfort and road holding ability. The optimal system parameters are considered under the fitness function composed of all the desired performance of a half-car model. The result of simulations shows that the PSS designed by using EP has better performances than currently-used PSS

  16. Potential Development of Vehicle Traction Levitation Systems with Magnetic Suspension

    A.V. Kireev; N.M. Kozhemyaka; G.N. Kononov

    2015-01-01

    Below is given the brief analysis of development trend for vehicle traction levitation systems with magnetic suspension. It is presented the assessment of potential development of traction levitation systems in terms of their simplicity. The examples are considered of technical solutions focused on reducing the complexity of transport systems. It is proposed the forecast of their further development.

  17. Potential Development of Vehicle Traction Levitation Systems with Magnetic Suspension

    A.V. Kireev

    2015-03-01

    Full Text Available Below is given the brief analysis of development trend for vehicle traction levitation systems with magnetic suspension. It is presented the assessment of potential development of traction levitation systems in terms of their simplicity. The examples are considered of technical solutions focused on reducing the complexity of transport systems. It is proposed the forecast of their further development.

  18. Digital control of wind tunnel magnetic suspension and balance systems

    Britcher, Colin P.; Goodyer, Michael J.; Eskins, Jonathan; Parker, David; Halford, Robert J.

    1987-01-01

    Digital controllers are being developed for wind tunnel magnetic suspension and balance systems, which in turn permit wind tunnel testing of aircraft models free from support interference. Hardware and software features of two existing digital control systems are reviewed. Some aspects of model position sensing and system calibration are also discussed.

  19. Design and Performance Assessment of a Semi-Active Suspension Model of Tractor Cabin

    I Ahmadi

    2016-04-01

    Full Text Available Cumulative effect of transmitted vibrations to the tractor driver not only leads to driver health problems, but also reduces the driver working efficiency. Tractor suspension system is one of the methods which is employed to lower the level of transmitted vibrations to the driver. In this study the design and performance assessment of a semi-active suspension model of tractor cabin was considered. Tractor full vibration model was developed first, and subsequently a semi-active ON-OFF damper model was designed. The examination of the model indicated that doubling the piston area and the volume of hydraulic accumulator air chamber, led to 39% increase and 31% reduction of the resonance frequency of transmitted vibrations to the driver, respectively. On the other hand doubling the piston area and the primary air pressure of the accumulator, affected the RMS of transmitted vibration to the driver by 77 cm s-2 reduction and 66 cm s-2 increase, respectively. Moreover, the numerical comparison of the model outputs with and without activation of semi-active cabin suspension, while the model was stimulated with the same input function, led to 43% improvement in RMS acceleration of the transmitted vibrations to the tractor seat. Therefore, the designed semi-active suspension model of cabin was able to attenuate the level of transmitted vibrations to the tractor driver.

  20. Magnetic suspension and balance system advanced study, 1989 design

    Boom, Roger W.; Eyssa, Y. M.; Abdelsalam, Moustafa K.; Mcintosh, Glen E.

    1991-01-01

    The objectives are to experimentally confirm several advanced design concepts on the Magnetic Suspension and Balance Systems (MSBS). The advanced design concepts were identified as potential improvements by Madison Magnetics, Inc. (MMI) during 1984 and 1985 studies of an MSBS utilizing 14 external superconductive coils and a superconductive solenoid in an airplane test model suspended in a wind tunnel. This study confirmed several advanced design concepts on magnetic suspension and balance systems. The 1989 MSBS redesign is based on the results of these experiments. Savings of up to 30 percent in supporting magnet ampere meters and 50 percent in energy stored over the 1985 design were achieved.

  1. A magnetic suspension system for measuring liquid density

    Luz María Centeno González

    2013-04-01

    Full Text Available Density is a derived quantity of mass and length; it is defined as mass per volume unit and its SI unit is kg/m3. National metrology institutes have been designing and building their own magnetic suspension systems during the last 5 decades for making fluid density measurements; this has allowed them to carry out research into liquids and gases’ physical characteristics. This paper was aimed at designing and developing a magnetic suspension system for a magnetic balance used in determining liquid density to be used in CENAM’s metrology density laboratories.

  2. Numerical study of hydrodynamic interactions and ordering in a 2-D micro-suspension of active agents

    Behmadi, Hojjat; Najafi, Ali

    2016-01-01

    Ordering in a 2-dimensional active micro-suspension is a challenging phenomenon. Taking into account both the Vicsek short range ordering and also the far field hydrodynamic (HD) interactions mediated by the ambient fluid, we investigate the role of HD interaction in the ordering phenomena in an active suspension. We observe that depending on the number density of swimmers and the strength of noise, the HD interaction can either enhance or weaken the ordering in a suspension. For a fixed value of noise, at large densities of particles, long range interactions enhance the order and clustering in the system but, at smaller densities, HD decreases the order.

  3. Investigation of Equivalent Unsprung Mass and Nonlinear Features of Electromagnetic Actuated Active Suspension

    Jun Yin

    2015-01-01

    Full Text Available Electromagnetic actuated active suspension benefits active control and energy harvesting from vibration at the same time. However, the rotary type electromagnetic actuated active suspension introduces a significant extra mass on the unsprung mass due to the inertia of the rotating components of the actuator. The magnitude of the introduced unsprung mass is studied based on a gearbox type actuator and a ball screw type actuator. The geometry of the suspension and the actuator also influence the equivalent unsprung mass significantly. The suspension performance simulation or control logic derived should take this equivalent unsprung mass into account. Besides, an extra force should be compensated due to the nonlinear features of the suspension structure and it is studied. The active force of the actuator should compensate this extra force. The discovery of this paper provides a fundamental for evaluating the rotary type electromagnetic actuated active suspension performance and control strategy derived as well as controlling the electromagnetic actuated active suspension more precisely.

  4. The Application of Fuzzy Control Algorithm of Vehicle with Active Suspensions

    Chuan-yin Tang

    2012-08-01

    Full Text Available In this study, a fuzzy logic control design is represented for the control of an active suspension system. A seven degrees of freedom non linear full vehicle model is established, instead of two degrees of freedom one quarter model and four degrees of freedom half body model and the road roughness intensity is modeled as a white noise stochastic process. Then a fuzzy logic controller is designed for the control of the seven degrees of freedom full vehicle model, the input variables are the suspension displacement and the output variables are the control force. The time responses of the full vehicle model are obtained, not only the vertical body acceleration, but also the roll angular acceleration and pitch angular acceleration. Finally, uncontrolled and controlled cases are compared. With the aid of software Matlab/simulink, simulation process is done. Simulation results indicate that the proposed active suspension system proves to be effective in the vibration isolation of the suspension system both in ride comfort and in stability.

  5. Optimization of Front Axle Suspension System of Articulated Dump Truck

    Langer, Thomas Heegaard; Christensen, Brian B.; Mouritsen, Ole Ø.;

    2010-01-01

    that has been subjected to comfort improvement is a two axle articulated dump truck. The comfort has been in terms of whole body vibration exposure and the overall improvement has been made possible by adding front axle suspension. However, a hydraulic stabilizing system between the tractor and trailer...... to evaluate the whole body vibrations. By use of a multibody simulation model of the dump truck the whole body vibration exposure has been computed using the predefined work cycle as model input. The design parameters comprise the components of the hydraulic subsystem of the suspension, i.e., the size...

  6. 15 CFR 2011.207 - Suspension of the certificate system.

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Suspension of the certificate system. 2011.207 Section 2011.207 Commerce and Foreign Trade Regulations Relating to Foreign Trade Agreements OFFICE OF THE UNITED STATES TRADE REPRESENTATIVE ALLOCATION OF TARIFF-RATE QUOTA ON IMPORTED...

  7. 15 CFR 2011.110 - Suspension of certificate system.

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Suspension of certificate system. 2011.110 Section 2011.110 Commerce and Foreign Trade Regulations Relating to Foreign Trade Agreements OFFICE OF THE UNITED STATES TRADE REPRESENTATIVE ALLOCATION OF TARIFF-RATE QUOTA ON IMPORTED...

  8. State observer-based sliding mode control for semi-active hydro-pneumatic suspension

    Ren, Hongbin; Chen, Sizhong; Zhao, Yuzhuang; Liu, Gang; Yang, Lin

    2016-02-01

    This paper proposes an improved virtual reference model for semi-active suspension to coordinate the vehicle ride comfort and handling stability. The reference model combines the virtues of sky-hook with ground-hook control logic, and the hybrid coefficient is tuned according to the longitudinal and lateral acceleration so as to improve the vehicle stability especially in high-speed condition. Suspension state observer based on unscented Kalman filter is designed. A sliding mode controller (SMC) is developed to track the states of the reference model. The stability of the SMC strategy is proven by means of Lyapunov function taking into account the nonlinear damper characteristics and sprung mass variation of the vehicle. Finally, the performance of the controller is demonstrated under three typical working conditions: the random road excitation, speed bump road and sharp acceleration and braking. The simulation results indicated that, compared with the traditional passive suspension, the proposed control algorithm can offer a better coordination between vehicle ride comfort and handling stability. This approach provides a viable alternative to costlier active suspension control systems for commercial vehicles.

  9. Development of a 60 cm Magnetic Suspension System

    Sawada, Hideo; Kunimasu, Tetsuya

    A 60cm Magnetic Suspension Balance System (MSBS), which has been developed in the National Aerospace Laboratory of Japan (NAL), is described in detail. Magnetic field in the MSBS is evaluated analytically and is compared with measured one. Available magnet kinds for the MSBS are selected analytically. The optimum ratio of diameter to length of cylindrical magnet for the MSBS is also evaluated. A model position sensing and the control systems are described with calibration test results. A model holding system is also shown, which is necessary for worker’s safety at suspending a large and massive model. The control system is presented and the measured model position during suspension is examined. The balance accuracy is examined and its error of drag force can be improved by restricting the calibration test to an expected drag range. Flow of the 60cm low-speed wind tunnel equipped with the MSBS is examined to be available for wind tunnel tests.

  10. Optimal Observer Control Approach To Quarter Car Model With Active Suspension

    Dinçer Maden

    2013-08-01

    Full Text Available As technological advances in automotive industry and roads construction techniques have made transportation faster, new comfort and safety matters have become the subject of engineering. Many vibrations caused by internal and external factors affect comfort and safety in negative ways. To damp these vibrations, active suspensions requiring controllers because of their complex structures are widely used. In this study, firstly ¼ car model having active suspension has been modeled with Luenberger observer, used on the occasions state variables cannot be determined efficiently. Then, the system has been combined with optimal feedback controller according to certain performance criteria. This new controller has been designed in MATLAB / SIMULINK environment, and the system response has been evaluated after applying roads disturbance inputs.

  11. Progress towards large wind tunnel magnetic suspension and balance systems

    Britcher, C. P.

    1984-01-01

    Recent developments and current research efforts leading towards realization of a large scale production wind tunnel Magnetic Suspension and Balance facility are reviewed. Progress has been made in the areas of model roll control, high angle-of-attack testing, digital system control, high magnetic moment superconducting solenoid model cores, and system failure tolerance. Formal design studies of large scale facilities have commenced and are continuing.

  12. MEMS mass-spring-damper systems using an out-of-plane suspension scheme

    Abdel Aziz, Ahmed Kamal Said

    2014-02-04

    MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) using an out-of-plane (or vertical) suspension scheme, wherein the suspensions are normal to the proof mass, are disclosed. Such out-of-plane suspension scheme helps such MEMS mass-spring-damper systems achieve inertial grade performance. Methods of fabricating out-of-plane suspensions in MEMS mass-spring-damper systems (including MEMS gyroscopes and accelerometers) are also disclosed.

  13. The modecleaner system and suspension aspects of GEO 600

    GEO 600 uses two 8 m triangular ring cavities as a modecleaner system for the stabilization of the laser. To isolate the cavities with respect to the seismic noise the optical components are suspended as double pendulums. The resonances of these pendulums are damped by a local-control loop via magnet-coil actuators acting on the intermediate masses. The suspension scheme and the measured key data (i.e. finesse, linewidth, visibility, throughput and in-lock durations of the cavities, as well as the isolation performance and the resulting frequency stability) of the modecleaner system will be given in this paper. Furthermore an overview of the GEO 600 interferometer suspension will be given

  14. NASA Langley Magnetic Suspension/Balance System

    1991-01-01

    A shuttle model is magnetically suspended in the transparent hexagonal test section of the MIT/NASA Langley 6 inch MSBS. Massive power supplies are required to drive electromagnets for model position control. A unique electromagnetic position sensor, similar to a linear variable differential transformer, provides five degrees of freedom for the test model. The low speed (Mach 0.5) wind tunnel was hand crafted from mahogany. Aerodynamic forces on the test model are measured by the proportional electrical current used to hold the model in place. The system was built by MIT in the late sixties, and was relocated to Langley in the mid eighties. In a joint effort with Old Dominion University in 1992 the MSBS was used to test the aerodynamics of store separation, simulating a bomb released from an aircraft. The system has been donated to Old Dominion University.

  15. The 13-inch magnetic suspension and balance system wind tunnel

    Johnson, William G., Jr.; Dress, David A.

    1989-01-01

    NASA Langley has a small, subsonic wind tunnel in use with the 13-inch Magnetic Suspension and Balance System (MSBS). The tunnel is capable of speeds up to Mach 0.5. This report presents tunnel design and construction details. It includes flow uniformity, angularity, and velocity fluctuation data. It also compares experimental Mach number distribution data with computed results for the General Electric Streamtube Curvature Program.

  16. Performance analysis of a semi-active railway vehicle suspension featuring MR dampers

    Kim, Hwan-Choong; Choi, Seung-Bok; Lee, Gyu-Seop; An, Chae-Hun; You, Won-Hee

    2014-03-01

    This paper presents performance analysis of semi-active railway vehicle suspension system using MR damper. In order to achieve this goal, a mathematical dynamic model of railway vehicle is derived by integrating car body, bogie frame and wheel-set which can be able to represent lateral, yaw and roll motion. Based on this model, the dynamic range of MR damper at the railway secondary suspension system and design parameters of MR damper are calculated. Subsequently, control performances of railway vehicle including car body lateral motion and acceleration of MR damper are evaluated through computer simulations. Then, the MR damper is manufactured to be retrofitted with the real railway vehicle and its characteristics are experimentally measured. Experimental performance of MR damper is assessed using test rig which is composed of a car body and two bogies.

  17. Collective motion in an active suspension of Escherichia coli bacteria

    We investigate experimentally the emergence of collective motion in the bulk of an active suspension of Escherichia coli bacteria. When increasing the concentration from a dilute to a semi-dilute regime, we observe a continuous crossover from a dynamical cluster regime to a regime of ‘bio-turbulence’ convection patterns. We measure a length scale characterizing the collective motion as a function of the bacteria concentration. For bacteria fully supplied with oxygen, the increase of the correlation length is almost linear with concentration and at the largest concentrations tested, the correlation length could be as large as 24 bacterial body sizes (or 7–8 when including the flagella bundle). In contrast, under conditions of oxygen shortage the correlation length saturates at a value of around 7 body lengths. (paper)

  18. Force Measurements in Magnetic Suspension and Balance System

    Kuzin, Alexander; Shapovalov, George; Prohorov, Nikolay

    1996-01-01

    The description of an infrared telemetry system for measurement of drag forces in Magnetic Suspension and Balance Systems (MSBS) is presented. This system includes a drag force sensor, electronic pack and transmitter placed in the model which is of special construction, and receiver with a microprocessor-based measuring device, placed outside of the test section. Piezosensitive resonators as sensitive elements and non-magnetic steel as the material for the force sensor are used. The main features of the proposed system for load measurements are discussed and the main characteristics are presented.

  19. Using the lead vehicle as preview sensor in convoy vehicle active suspension control

    Rahman, Mustafizur; Rideout, Geoff

    2012-12-01

    Both ride quality and roadholding of actively suspended vehicles can be improved by sensing the road ahead of the vehicle and using this information in a preview controller. Previous applications have used look-ahead sensors mounted on the front bumper to measure terrain beneath. Such sensors are vulnerable, potentially confused by water, snow, or other soft obstacles and offer a fixed preview time. For convoy vehicle applications, this paper proposes using the overall response of the preceding vehicle(s) to generate preview controller information for follower vehicles. A robust observer is used to estimate the states of a quarter-car vehicle model, from which road profile is estimated and passed on to the follower vehicle(s) to generate a preview function. The preview-active suspension, implemented in discrete time using a shift register approach to improve simulation time, reduces sprung mass acceleration and dynamic tyre deflection peaks by more than 50% and 40%, respectively. Terrain can change from one vehicle to the next if a loose obstacle is dislodged, or if the vehicle paths are sufficiently different so that one vehicle misses a discrete road event. The resulting spurious preview information can give suspension performance worse than that of a passive or conventional active system. In this paper, each vehicle can effectively estimate the road profile based on its own state trajectory. By comparing its own road estimate with the preview information, preview errors can be detected and suspension control quickly switched from preview to conventional active control to preserve performance improvements compared to passive suspensions.

  20. A review of dynamic stability of repulsive-force maglev suspension systems

    Cai, Y.; Rote, D.M.

    1998-07-01

    Vehicle dynamics and the need to satisfy ride quality requirements have long been recognized as crucial to the commercial success of passenger-carrying transportation systems. Design concepts for maglev systems are no exception. Early maglev investigators and designers were well aware of the importance of ride quality and took care to ensure that their designs would meet acceptable ride quality standards. In contrast, the dynamic stability of electrodynamic suspension (EDS) systems, which has obvious implications for system safety and cost as well as for ride quality, has not received nearly as much attention. Because of the well-known under-damped nature of EDS suspension systems and the observation of instabilities in laboratory-scale model systems, it is prudent to develop a better understanding of vehicle stability characteristics. The work reported in this was undertaken with the intention of summarizing information that has been accumulated worldwide and that is relevant to dynamic stability of repulsive-force maglev suspension systems, assimilating that information, and gaining an understanding of the factors that influence that stability. Included in the paper is a discussion and comparison of results acquired from some representative tests of large-scale vehicles on linear test tracks, together with analytical and laboratory-scale investigations of stability and dynamics of EDS systems. This paper will also summarize the R and D activities at Argonne National Laboratory (ANL) since 1991 to study the nature of the forces that are operative in an EDS system and the dynamic stability of such systems.

  1. Reading a suspenseful literary text activates brain areas related to social cognition and predictive inference.

    Lehne, Moritz; Engel, Philipp; Rohrmeier, Martin; Menninghaus, Winfried; Jacobs, Arthur M; Koelsch, Stefan

    2015-01-01

    Stories can elicit powerful emotions. A key emotional response to narrative plots (e.g., novels, movies, etc.) is suspense. Suspense appears to build on basic aspects of human cognition such as processes of expectation, anticipation, and prediction. However, the neural processes underlying emotional experiences of suspense have not been previously investigated. We acquired functional magnetic resonance imaging (fMRI) data while participants read a suspenseful literary text (E.T.A. Hoffmann's "The Sandman") subdivided into short text passages. Individual ratings of experienced suspense obtained after each text passage were found to be related to activation in the medial frontal cortex, bilateral frontal regions (along the inferior frontal sulcus), lateral premotor cortex, as well as posterior temporal and temporo-parietal areas. The results indicate that the emotional experience of suspense depends on brain areas associated with social cognition and predictive inference. PMID:25946306

  2. Reading a suspenseful literary text activates brain areas related to social cognition and predictive inference.

    Moritz Lehne

    Full Text Available Stories can elicit powerful emotions. A key emotional response to narrative plots (e.g., novels, movies, etc. is suspense. Suspense appears to build on basic aspects of human cognition such as processes of expectation, anticipation, and prediction. However, the neural processes underlying emotional experiences of suspense have not been previously investigated. We acquired functional magnetic resonance imaging (fMRI data while participants read a suspenseful literary text (E.T.A. Hoffmann's "The Sandman" subdivided into short text passages. Individual ratings of experienced suspense obtained after each text passage were found to be related to activation in the medial frontal cortex, bilateral frontal regions (along the inferior frontal sulcus, lateral premotor cortex, as well as posterior temporal and temporo-parietal areas. The results indicate that the emotional experience of suspense depends on brain areas associated with social cognition and predictive inference.

  3. Combined control effects of brake and active suspension control on the global safety of a full-car nonlinear model

    Tchamna, Rodrigue; Youn, Edward; Youn, Iljoong

    2014-05-01

    This paper focuses on the active safety of a full-vehicle nonlinear model during cornering. At first, a previously developed electronic stability controller (ESC) based on vehicle simplified model is applied to the full-car nonlinear model in order to control the vehicle yaw rate and side-slip angle. The ESC system was shown beneficial not only in tracking the vehicle path as close as possible, but it also helped in reducing the vehicle roll angle and influences ride comfort and road-holding capability; to tackle that issue and also to have better attitude motion, making use of optimal control theory the active suspension control gain is developed from a vehicle linear model and used to compute the active suspension control force of the vehicle nonlinear model. The active suspension control algorithm used in this paper includes the integral action of the suspension deflection in order to make zero the suspension deflection steady state and keep the vehicle chassis flat. Keeping the chassis flat reduces the vehicle load transfer and that is helpful for road holding and yaw rate tracking. The effects of the two controllers when they work together are analysed using various computer simulations with different steering wheel manoeuvres.

  4. Magnetic Suspension and Balance Systems: A Selected, Annotated Bibliography

    Tuttle Marie H.; Kilgore, Robert A.; Boyden, Richmond P.

    1983-01-01

    This publication, containing 206 entries, supersedes an earlier bibliography, NASA TM-80225 (April 1980). Citations for 18 documents have been added in this updated version. Most of the additions report results of recent studies aimed at increasing the research capabilities of magnetic suspension and balance systems, e.g., increasing force and torque capability, increasing angle of attack capability, and increasing overall system reliability. Some of the additions address the problem of scaling from the relatively small size of existing systems to much larger sizes. The purpose of this bibliography is to provide an up-to-date list of publications that might be helpful to persons interested in magnetic suspension and balance systems for use in wind tunnels. The arrangement is generally chronological by date of publication. However, papers presented at conferences or meetings are placed under dates of presentation. The numbers assigned to many of the citations have been changed from those used in the previous bibliography. This has been done in order to allow outdated citations to be removed and some recently discovered older works to be included in their proper chronological order.

  5. Design and analysis of the SSC (Superconducting Super Collider) dipole magnet suspension system

    Nicol, T.H.; Niemann, R.C.; Gonczy, J.D.

    1989-03-01

    The design of the suspension system for Superconducting Super Collider (SSC) dipole magnets has been driven by rigorous thermal and structural requirements. The current system, designed to meet those requirements, represents a significant departure from previous superconducting magnet suspension system designs. This paper will present a summary of the design and analysis of the vertical and lateral suspension as well as the axial anchor system employed in SSC dipole magnets. 5 refs., 9 figs., 4 tabs.

  6. Dynamic stability of repulsive-force maglev suspension systems

    Cai, Y.; Rote, D.M.; Mulcahy, T.M.; Wang, Z. [and others

    1996-11-01

    This report summarizes the research performed on maglev vehicle dynamic stability at Argonne National Laboratory during the past few years. It also documents both measured and calculated magnetic-force data. Because dynamic instability is not acceptable for any commercial maglev system, it is important to consider this phenomenon in the development of all maglev systems. This report presents dynamic stability experiments on maglev systems and compares the results with predictions calculated by a nonlinear-dynamics computer code. Instabilities of an electrodynamic-suspension system type vehicle model were obtained by experimental observation and computer simulation of a five-degree-of-freedom maglev vehicle moving on a guideway that consists of a pair of L-shaped aluminum conductors attached to a rotating wheel. The experimental and theoretical analyses developed in this study identify basic stability characteristics and future research needs of maglev systems.

  7. Bandwidth-limited active suspension controller for an off-road vehicle based on co-simulation technology

    Jinzhi FENG; Songlin ZHENG; Fan YU

    2008-01-01

    This paper presents the design process of a controller for bandwidth-limited active hydro-pneumatic suspension employed by an off-road vehicle based on co-simulation technology. First, a detailed multi-body dynamic model of the vehicle is established by using the ADAMS/View software package, which is followed by validation using a vehicle field test. Second, a combined PID and fuzzy controller is designed for the bandwidth-limited active suspension system and then programmed by means of S-functions in Matlab/Simulink, to which a data exchange interface with ADAMS/View is also defined. Third, the proposed control algorithm is implemented on the multi-body dynamic vehicle model to enable the co-simulation to run repeatedly until a more practical controller is achieved. In the end, the proposed active suspension system is compared with a conven-tional passive system. Simulation results show that the proposed active suspension system considerably improves both the ride and handling performance of the vehicle and therefore increases the maximum travel-ing speeds even on rough roads.

  8. Theoretical analysis and evaluation of an optimally controlled full-car vehicle model with a variable-damping semi-active vehicle suspension forced by measured road inputs

    This study aims to obtain the optimal control algorithm for a full-car model with a variable-damping semi-active suspension, such as a magnetorheological damper, by solving the linear quadratic regulator problem, and then to evaluate the system performance if the control inputs are constrained and delayed, and the vehicle is subjected to measured road inputs. A seven-degree of freedom full-car vehicle model was considered, and the state equations of the system were obtained in bilinear form. An integral performance index involving a weighted combination of the mean squares of average sprung mass acceleration and suspension deflections was defined. Trade-off curves were obtained between the sprung mass acceleration and suspension deflections of the optimally controlled system which is subjected to a measured road profile input. Performance of the optimally controlled system was compared to the performance of the corresponding optimum passive suspension system. For the vehicle parameters and the road input profile considered in this study, a reduction of 6.4% in the average vertical acceleration and 2.8% in the average suspension deflection was achieved by the semi-active suspensions. The response of the system to an initial condition has shown that its transient oscillations are damped out effectively by the semi-active suspension.

  9. Digital Control Analysis and Design of a Field-Sensed Magnetic Suspension System

    Jen-Hsing Li

    2015-03-01

    Full Text Available Magnetic suspension systems are mechatronic systems and crucial in several engineering applications, such as the levitation of high-speed trains, frictionless bearings, and wind tunnels. Magnetic suspension systems are nonlinear and unstable systems; therefore, they are suitable educational benchmarks for testing various modeling and control methods. This paper presents the digital modeling and control of magnetic suspension systems. First, the magnetic suspension system is stabilized using a digital proportional-derivative controller. Subsequently, the digital model is identified using recursive algorithms. Finally, a digital mixed linear quadratic regulator (LQR/H∞ control is adopted to stabilize the magnetic suspension system robustly. Simulation examples and a real-world example are provided to demonstrate the practicality of the study results. In this study, a digital magnetic suspension system model was developed and reviewed. In addition, equivalent state and output feedback controls for magnetic suspension systems were developed. Using this method, the controller design for magnetic suspension systems was simplified, which is the novel contribution of this study. In addition, this paper proposes a complete digital controller design procedure for magnetic suspension systems.

  10. Stress analysis on SSC cryogenic shaft transfer line suspension system

    The Superconducting Super Collider has a total of twelve refrigeration plants. Each plant requires a cryogenic transfer line to connect the above-ground refrigerator to the below-ground collider main ring. The transfer line consists of seven cryogenic circuits enclosed in a cryostat. It is to be built in a number of pieces (modules) and assembled on-site. Within each transfer line module, the internal elements including the circuit tubes, thermal shield, and multilayer insulation (MLI) blankets are supported by an internal suspension system. The suspension system for a module consists of a longitudinal support and four radial supports. The radial supports restrict any radial movement of the internal elements while allowing longitudinal thermal movement. The longitudinal support anchors all the internal elements to the vacuum jacket. Each type of support consists of three plates for supporting the circuit tubes at three designated temperature levels (4, 20, and 80 K), and two sets of stand-off rods which make joints between the 4 and 20 K plates, and between the 20 and 80 K plates

  11. Dynamics of inert spheres in active suspensions of micro-rotors.

    Yeo, Kyongmin; Lushi, Enkeleida; Vlahovska, Petia M

    2016-07-01

    Inert particles suspended in active fluids of self-propelled particles are known to often exhibit enhanced diffusion and novel coherent structures. Here we numerically investigate the dynamical behavior and self-organization in a system consisting of passive and actively rotating spheres of the same size. The particles interact through direct collisions and the fluid flows generated as they move. In the absence of passive particles, three states emerge in a binary mixture of spinning spheres depending on particle fraction: a dilute gas-like state where the rotors move chaotically, a phase-separated state where like-rotors move in lanes or vortices, and a jammed state where crystals continuously assemble, melt and move (K. Yeo, E. Lushi, and P. M. Vlahovska, Phys. Rev. Lett., 2015, 114, 188301). Passive particles added to the rotor suspension modify the system dynamics and pattern formation: while states identified in the pure active suspension still emerge, they occur at different densities and mixture proportions. The dynamical behavior of the inert particles is also non-trivially dependent on the system composition. PMID:27265340

  12. Magnetic suspension and balance system advanced study, phase 2

    Boom, R. W.; Abdelsalam, M. K.; Eyssa, Y. M.; Mcintosh, G. E.

    1990-01-01

    The design improvements for the system encompass 14 or 18 external superconductive coils mounted on a 8 x 8 foot wind tunnel, a superconductive model core magnet on a holmium mandrel to fit an F-16 model, model wings of permanent magnet material Nd2Fe14B, and fiber glass epoxy structure. The Magnetic Suspension and Balance System (MSBS) advanced design is confirmed by the successful construction and test of a full size superconductive model core solenoid with holmium mandrel. The solenoid is 75 cm long and 12.6 cm in diameter and produces 6.1 tesla for a hold time of 47 minutes. An integrated coil system design of a new compact configuration without specific coils for roll or pitch shows promise of simplicity; magnet reductions of 30 percent compared to the most recent 1985 design are possible.

  13. 22 CFR 1006.110 - What is the purpose of the nonprocurement debarment and suspension system?

    2010-04-01

    ... nonprocurement debarment and suspension system? (a) To protect the public interest, the Federal Government ensures the integrity of Federal programs by conducting business only with responsible persons. (b)...

  14. 22 CFR 1508.110 - What is the purpose of the nonprocurement debarment and suspension system?

    2010-04-01

    ... nonprocurement debarment and suspension system? (a) To protect the public interest, the Federal Government ensures the integrity of Federal programs by conducting business only with responsible persons. (b)...

  15. Modeling and Identification of a Large Gap Magnetic Suspension System

    Cox, David E. (Editor); Groom, Nelson J. (Editor); Hsiao, Min-Hung; Huang, Jen-Kuang

    1996-01-01

    This paper presents the results of modeling and system identification efforts on the NASA Large-Angle Magnetic Suspension Test Fixture (LAMSTF). The LAMSTF consists of a cylindrical permanent magnet which is levitated above a planar array of five electromagnets mounted in a circular configuration. The analytical model is first developed and open-loop characteristics are described. The system is shown to be highly unstable and requires feedback control in order to apply system identification. Limitations on modeling accuracy due to the effect of eddy-currents on the system are discussed. An algorithm is derived to identify a state-space model for the system from input/output data acquired during closed-loop operation. The algorithm is tested on both the baseline system and a perturbed system which has an increased presence of eddy currents. It is found that for the baseline system the analytic model adequately captures the dynamics, although the identified model improves the simulation accuracy. For the system perturbed by additional unmodeled eddy-currents the analytic model is no longer adequate and a higher-order model, determined through system identification, is required to accurately predict the system's time response.

  16. Progress towards extreme attitude testing with Magnetic Suspension and Balance Systems

    Britcher, Colin P.; Parker, David H.

    1988-01-01

    Progress is reported in a research effort aimed towards demonstration of the feasibility of suspension and aerodynamic testing of models at high angles of attack in wind tunnel Magnetic Suspension and Balance Systems. Extensive modifications, described in this paper, have been made to the Southampton University suspension system in order to facilitate this work. They include revision of electromagnet configuration, installation of all-new position sensors and expansion of control system programs. An angle of attack range of 0 to 90 deg is expected for axisymmetric models. To date, suspension up to 80 deg angle of attack has been achieved.

  17. A Digital Control Algorithm for Magnetic Suspension Systems

    Britton, Thomas C.

    1996-01-01

    An ongoing program exists to investigate and develop magnetic suspension technologies and modelling techniques at NASA Langley Research Center. Presently, there is a laboratory-scale large air-gap suspension system capable of five degree-of-freedom (DOF) control that is operational and a six DOF system that is under development. Those systems levitate a cylindrical element containing a permanent magnet core above a planar array of electromagnets, which are used for levitation and control purposes. In order to evaluate various control approaches with those systems, the Generic Real-Time State-Space Controller (GRTSSC) software package was developed. That control software package allows the user to implement multiple control methods and allows for varied input/output commands. The development of the control algorithm is presented. The desired functionality of the software is discussed, including the ability to inject noise on sensor inputs and/or actuator outputs. Various limitations, common issues, and trade-offs are discussed including data format precision; the drawbacks of using either Direct Memory Access (DMA), interrupts, or program control techniques for data acquisition; and platform dependent concerns related to the portability of the software, such as memory addressing formats. Efforts to minimize overall controller loop-rate and a comparison of achievable controller sample rates are discussed. The implementation of a modular code structure is presented. The format for the controller input data file and the noise information file is presented. Controller input vector information is available for post-processing by mathematical analysis software such as MATLAB1.

  18. Polyphenoloxidase-activity and -activation in embryogenic and non-embryogenic suspension cultures of Euphorbia pulcherrima.

    Grotkass, C; Lieberei, R; Preil, W

    1995-04-01

    The activity and activation potential of polyphenoloxidase (PPO, E.C. 1.10.3.1.) of tissue from shoot tips, adult leaves and embryogenic and non-embryogenic cell suspension cultures of Euphorbia pulcherrima was investigated using an oxygen probe technique. PPO derived from differentiated in vivo plant tissue (shoot tips, leaves) cannot be activated either by storage at 0-4°, freezing and thawing, incubation with CaCl2, sodium dodecyl sulfate or by incubation with trypsin. Embryogenic cells are characterized by high initial PPO activity and strong activation potential of membrane bound enzyme. Non-embryogenic material reveals low phenolase activity and low activation potential. An activation quotient (based on the ratio between "PPO-activity determined after sodium dodecyl sulfate incubation" to "PPO-activity determined after CaCl2-incubation") was calculated. This is independent of absolute enzyme activity and can be used for characterization of the embryogenic status of cells. PMID:24185450

  19. Optimal Observer Control Approach To Quarter Car Model With Active Suspension

    Dinçer Maden

    2013-01-01

    As technological advances in automotive industry and roads construction techniques have made transportation faster, new comfort and safety matters have become the subject of engineering. Many vibrations caused by internal and external factors affect comfort and safety in negative ways. To damp these vibrations, active suspensions requiring controllers because of their complex structures are widely used. In this study, firstly ¼ car model having active suspension has been modeled with Luenberg...

  20. Damage model for automobile suspension system subjected to cyclic loading

    The Continuum damage mechanics (CDM) modeling, a state-of-the art modeling technique, because of its recognized potential has grasped the attention of many researchers in the area of constitutive modeling. An anisotropic continuum damage model for predicting the response of Auto Mobile Suspension System (AMSS) subjected to cyclic loading is presented in this study. The model utilizes an appropriate damage-effect tensor M in constructing the constitutive equations and evolution of damage. The concept of multiple bounding surfaces is used, with a varying size limit fracture surface defining cyclic loading in contrast to a fixed size limit fracture surface for static loading. The model after calibration is shown to predict the stress-strain path for AMSS as well as S-N curves depicting the fatigue response of AMSS. (author)

  1. Preview control of vehicle suspension system featuring MR shock absorber

    This paper presents control performance evaluation of optimal preview control algorithm for vehicle suspension featuring MR shock absorber. The optimal preview control algorithm has several advantages such as high control performance over that which is best for a non-preview system. In order to achieve this goal, a commercial MR shock absorber, Delphi MganerideTM, which is applicable to high class passenger vehicle, is adopted and its field-dependent damping force and dynamic responses are experimentally evaluated. Then the governing equation of motion for the full-vehicle model is established and integrated with the MR shock absorber. Subsequently, optimal controller with preview control algorithm is formulated and implemented for vibration suppression of the car body. Control performance of the preview controller is evaluated for the full-vehicle model under random road condition. In addition, the control performances depending on preview distances are evaluated.

  2. Biphasic Effects of α-Asarone on Immobility in the Tail Suspension Test: Evidence for the Involvement of the Noradrenergic and Serotonergic Systems in Its Antidepressant-Like Activity

    Chellian, Ranjithkumar; Pandy, Vijayapandi; Mohamed, Zahurin

    2016-01-01

    Alpha (α)-asarone is one of the main psychoactive compounds, present in Acorus species. Evidence suggests that the α-asarone possess an antidepressant-like activity in mice. However, the exact dose-dependent effect of α-asarone and mechanism(s) involved in the antidepressant-like activity are not clear. The present study aimed to investigate the dose-dependent effect of α-asarone and the underlining mechanism(s) involved in the antidepressant-like activity of α-asarone in the mouse model of tail suspension test (TST). In this study, the acute effect of α-asarone per se at different doses (10–100 mg/kg, i.p.) on immobility in the TST was studied. Additionally, the possible mechanism(s) involved in the antidepressant-like effect of α-asarone was studied using its interaction with noradrenergic and serotonergic neuromodulators in the TST. The present results reveal that the acute treatment of α-asarone elicited biphasic responses on immobility such that the duration of the immobility time is significantly reduced at lower doses (15 and 20 mg/kg, i.p.) but increased at higher doses (50 and 100 mg/kg, i.p.) in the TST. Besides, α-asarone at higher doses (50 and 100 mg/kg, i.p.) significantly decreased the spontaneous locomotor activity. Moreover, pretreatment of mice with noradrenergic neuromodulators such as AMPT (100 mg/kg, i.p., a catecholamine synthesis inhibitor), prazosin (1 mg/kg, i.p., an α1-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α2-adrenoceptor antagonist) and with serotonergic neuromodulators such as PCPA (100 mg/kg, i.p., once daily for four consecutive days, a serotonin synthesis inhibitor,) and WAY100635 (0.1 mg/kg, s.c., a selective 5-HT1A receptor antagonist) significantly reversed the anti-immobility effect of α-asarone (20 mg/kg, i.p.). Taken together, our results suggest that the acute treatment with α-asarone elicited biphasic actions in the TST in which antidepressant-like effect was seen at relatively lower doses (15

  3. Active suspension design for a Large Space Structure ground test facility

    Lange, Thomas J. H.; Schlegel, Clemens

    1993-01-01

    The expected future high performance requirements for Large Space Structures (LSS) enforce technology innovations such as active vibration damping techniques e.g., by means of structure sensors and actuators. The implementation of new technologies like that requires an interactive and integrated structural and control design with an increased effort in hardware validation by ground testing. During the technology development phase generic system tests will be most important covering verification and validation aspects up to the preparation and definition of relevant space experiments. For many applications using advanced designs it is deemed necessary to improve existing testing technology by further reducing disturbances and gravity coupling effects while maintaining high performance reliability. A key issue in this context is the improvement of suspension techniques. The ideal ground test facility satisfying these requirements completely will never be found. The highest degree of reliability will always be obtained by passive suspension methods taking into account severe performance limitations such as non-zero rigid body modes, restriction of degrees of freedom of motion and frequency response limitations. Passive compensation mechanisms, e.g., zero-spring-rate mechanisms, either require large moving masses or they are limited with respect to low-frequency performance by friction, stiction or other non-linear effects. With active suspensions these limitations can be removed to a large extent thereby increasing the range of applications. Despite an additional complexity which is associated with a potential risk in reliability their development is considered promising due to the amazing improvement of real-time control technology which is still continuing.

  4. A review of Magnetic Suspension and Balance Systems

    Boyden, Richmond P.

    1988-01-01

    This paper traces the development of Magnetic Suspension and Balance Systems (MSBSs) for use in wind tunnels. The expression MSBS implies a system that can both suspend a model and also measure the forces and moments acting on the model. This avoids the need for any mechanical support of the model. An MSBS uses electromagnets located outside the test section walls to create magnetic fields inside the test section. Measurement of the electrical current flowing in each of the electromagnets can be used to determine the forces and moments acting on the suspended model. An MSBS is capable of supporting a model with an internal magnetized core subject to gravity, aerodynamic, and inertial loads. The model must have a core made of either a permanent magnet, magnetized soft iron, or a solenoid. The position of the suspended body is inherently unstable. A closed-loop control system which includes a position sensing system has to control the position of the body by controlling the applied magnetic fields. This paper includes a discussion of all the known MSBSs and the outlook for larger systems.

  5. Sliding modes control of active suspensions for a non-linear full vehicle model

    In this study, a non-linear seven degrees of freedom vehicle model is used in order to design and check the performance of sliding modes controlled active suspensions. Force actuators are mounted as parallel to the four suspensions and a non-chattering control is realized. Sliding mode control is preferred because of its robust character since any change in vehicle parameters should not affect the performance of the active suspensions. Improvement in ride comfort is aimed by decreasing the amplitudes of motions of vehicle body. Body bounce, pitch and yaw motions of the vehicle are simulated both in time domain in case of traveling on a limited ramp type of road profile and frequency domain using linear zed vehicle model. Also phase plane plots of them are checked. Simulation results are compared with the ones of passive suspensions. (author)

  6. Semi-active variable stiffness vibration control of vehicle seat suspension using an MR elastomer isolator

    This paper presents a study on continuously variable stiffness control of vehicle seat suspension using a magnetorheological elastomer (MRE) isolator. A concept design for an MRE isolator is proposed in the paper and its behavior is experimentally evaluated. An integrated seat suspension model, which includes a quarter-car suspension and a seat suspension with a driver body model, is used to design a sub-optimal H∞ controller for an active isolator. The desired control force generated by this active isolator is then emulated by the MRE isolator through its continuously variable stiffness property when the actuating condition is met. The vibration control effect of the MRE isolator is evaluated in terms of driver body acceleration responses under both bump and random road conditions. The results show that the proposed control strategy achieves better vibration reduction performance than conventional on–off control

  7. A comparison of the pharmacological activity in cows of two suspensions of betamethasone alcohol.

    MacDiarmid, S C; Cooper, B S

    1982-12-01

    The activity of two betamethasone (BM) suspensions, which differed only in their solids:vehicle ratio, was examined in cattle. Two groups of 10 cows received by subcutaneous injection either 20 ml of a 2 mg/ml aqueous suspension of BM alcohol or 2 ml of a 20 mg/ml aqueous suspension. A further 10 cows served as a saline-treated control group. The mean peak plasma BM concentration was significantly higher in cows treated with 2 mg/ml suspension. However, plasma BM levels tended to be maintained for longer by the 20 mg/ml suspension. A depression of early morning cortisol levels, similar to that seen with other synthetic glucocorticoids, was recorded with both BM preparations; the depression outlasted the presence of BM. Plasma glucose levels and circulating neutrophil numbers were elevated by BM treatment, and the magnitude and duration of these changes was related to the solids:vehicle ratio of the injected suspensions. The more concentrated suspension was absorbed more slowly and thus produced effects of greater duration. PMID:16030844

  8. Fundamental connections between models of active suspensions and transversely-isotropic fluids

    Holloway, Craig R.; Cupples, Gemma; Smith, David J.; Green, J. Edward F.; Clarke, Richard J.; Dyson, Rosemary J.

    2016-01-01

    Suspensions of self-motile, elongated particles are a topic of significant current interest, exemplifying a form of 'active matter'. Examples include self-propelling bacteria, algae and sperm, and artificial swimmers. Ericksen's model of a transversely-isotropic fluid [J. L. Ericksen, Colloid Polym. Sci. 173(2):117-122 (1960)] treats suspensions of non-motile particles as a continuum with an evolving preferred direction; this model describes fibrous materials as diverse as extracellular matri...

  9. Bilinear Robust Control for Vertical Vibration in Railway Vehicle with Semi-Active Suspensions

    Umehara, Ryuichi; Otsuki, Masatsugu; Yoshida, Kazuo

    It is well known that the vibration control problem for automobiles and railway vehicles with semi-active suspensions is classified as a control problem in a bilinear system. Bullet trains and railway vehicles have lighter body in order to improve acceleration; these vibrations in the body are easily induced by various disturbances due to rigid and elastic dynamics. Currently, passive dampers such as air suspensions and axle springs are installed on railway vehicle trucks as countermeasures for such vibrations. This study presents an effective controller, based on the H∞ theory, for vibration suppression in railway vehicles and describes a method of synthesizing this robust controller by considering unstructured and structured uncertainties that are applicable to a bilinear system. The performance of the proposed controller and its robustness toward uncertainties are examined by numerical calculations that simulate a railway vehicle subjected to disturbances due to vertical uneven railway tracks, the variations in its mass due to boarding passengers, and the modeling errors caused by non-controlled modes. This enables a comparison of the proposed control method with the conventional one in terms of the robustness toward parameter variation. Thus, this result shows the high robustness and usefulness of the proposed controller.

  10. The Exact Linearization and LQR Control of Semiactive Connected Hydropneumatic Suspension System

    Xuyang Cao

    2015-01-01

    Full Text Available Based on differential geometry theory, the nonlinear system of connected hydropneumatic suspension was transformed to a linear one. What is more, it realized the decoupling and inverter between the control variables and system outputs. With LQR (Linear Quadratic Regulator control theory, a semiactive system has been developed for connected hydropneumatic suspension in this paper. By AMESim/Simulink cosimulation, the results show that the semiactive connected hydropneumatic suspension decreases the vibration of upper vehicle quickly and reduces the impact acceleration strongly both in displacement and inroll angle. Moreover, the semiactive suspension could increase the suspension dynamic deflection, which would make the system reach balance quickly and keep small vibration amplitude under the effect of disturbance.

  11. ANALYTIC AND NONLINEAR PROGNOSTIC FOR VEHICLE SUSPENSION SYSTEMS

    Abdo Abou Jaoude

    2013-01-01

    Full Text Available Predicting Remaining Useful Lifetime (RUL of industrial systems becomes currently an important aim for industrialists knowing that the expensive failure can occur suddenly. As the classical strategies of maintenance are not efficient and practical because they neglect the evolving product state and environment, the recent prognostic approaches try to fill this gap. This approach shows to be important in ensuring high availability in minimum costs for industrial systems, like in aerospace, defense, petro-chemistry and automobiles. An analytic prognostic methodology based on existing damage laws in fracture mechanics, such as Paris’ and Miner’s laws, is recently developed for determining the system RUL. Damages have been assumed to be accumulated linearly, since we have considered the widely used linear Miner’s law. In this study, the nonlinear case in damage accumulation is explored to take into account the complex behavior of some materials subject to fatigue effects. It is useful especially when the nature of applied constraints and influent environment contribute to accentuate this nonlinearity. Our damage model is based on the accumulation of a damage measurement D(N after each loading cycle N. In automobile industry, the prognostic assessment of the suspension component by this developed nonlinear approach shows its importance for the same earlier reasons.

  12. Multi-island Genetic Algorithm Opetimization of Suspension System

    Li-Wei Xu

    2012-11-01

    Full Text Available The suspension and the car's operating stability are closely linked. Through the optimization of the suspension, it can improve the operating stability of vehicle, which is very meaningful to enhance the performance of modern cars. With the development of science and technology, the traditional optimization methods often appear insufficient when it deals with the multi-objective optimization problem of the automotive suspension. As a kind of improved genetic algorithm, the multi-island genetic algorithm can handle the multi-objective problem very well. In order to improve the vehicle handling stability, in this paper, the multi-island genetic algorithm is used to optimize the suspension parameters, combined with the iSight-FD and the Adams/car.

  13. Evaluation of Antioxidant Enzyme Activity and Biochemical Characterization from Static and Suspension Culture of Withania somnifera L.

    Satyajit Kanungo

    2015-03-01

    Full Text Available Withania somnifera (L. Dunal, is an erect evergreen shrub commonly known as Ashwagandha. It is widely used in Ayurvedic and in the traditional pharmacopeia system of India. It is one of the major ingredients in many formulations prescribed for a variety of musculoskeletal conditions including arthritis and rheumatism. In the present study the variation in quality and quantity of protein and antioxidant enzymes were evaluated biochemically and enzymatically from the static and suspension cultures. The nodal segments had provided maximum callusing of 90.25±0.06 % with (1mg/l of BAP and Kn with (2mg/l of 2, 4-D. The static and suspension cultures were taken for the analysis of total soluble protein and screened for antioxidant enzyme activity [catalase (CAT, superoxide dismutase (SOD and guaiacol peroxidase (GPX]. The protein content (1.2016 µg/µl was found to be higher in static culture samples (0.870 µg/µl than the protein obtained from the suspension culture. The antioxidant enzyme activity (CAT, SOD and GPX was higher in static culture samples (301.01± 0.42, 198.92 ± 0.29, 103.75 ± 0.11 nkat/ mg of protein than that of suspension culture. Specific activity staining of isozyme pattern exhibited three isoforms (CAT 1, CAT 2 and CAT 3 in static culture samples but CAT 1 was absent in the sample extracted from suspension cultures.  In case of SOD, four bands (SOD 1, SOD 2, SOD 3 and SOD 4 were found in both the samples whereas intensity of GPX activity was found to be more in static culture but both the samples exhibited three isoforms such as  (GPX 1, GPX 2 and GPX 3. The supplementation of required nutrients along with the phytohormones under in vitro condition might be an enhancing factor to yield antioxidant enzymes in the static culture samples. 

  14. VFC - Variational Feedback Controller and its application to semi-active suspensions

    Pepe, G.; Carcaterra, A.

    2016-08-01

    Active and semi-active control of oscillating devices and structures is a challenging field and this paper proposes an original investigation based on variational controls that can be successfully applied to mechanical systems. The method produces a general class of new controllers, named VFC - Variational Feedback Controllers, that is the main theoretical contribution of the paper. The value of the theory relies on using a reformulation of the Variational Optimal Control Theory, that has in general the limit of producing control program strategies and not directly feedback control methods. The difficulties are in fact related to the intrinsic nature of the variational optimal control, that must solve initial and final boundary conditions. A special definition of the class of the considered objective functions, permits to skip this difficulty, producing a pure feedback control. The presented theory goes beyond with respect to the most acknowledged LQR variational-based techniques, in that VFC can be applied to more general nonlinear dynamical systems, even with finite time horizon. To test the effectiveness of the novel approach in real engineering problems, a deep investigation on nonlinear suspension systems treated by VFC is proposed in this paper. To this aim, VFC is systematically compared with the most recent methods available in this field and suitable to deal with nonlinear system control of car suspensions. In particular, the comparative analysis is made in terms of both comfort and handling key performance indexes, that permits to easily and significantly compare different control logics, such as the Sky-hook and Ground-hook control families, the Acceleration and Power Driven Dampers. The results of this comparison are collected in a performance plane, having comfort and handling indexes as coordinate axes, showing that VFC controllers completely cover the regions reached by the other mentioned control logics in this plane, but reveal to have access to

  15. Non-equilibrium Stokes-Einstein relation via active microrheology of hydrodynamically interacting suspensions

    Chu, Henry; Zia, Roseanna

    In our recently developed non-equilibrium Stokes-Einstein relation, we showed that, in the absence of hydrodynamic interactions, the stress in a suspension is given by a balance between fluctuation and dissipation. Here, we generalize our theory for systems of hydrodynamically interacting colloids, via active microrheology, where motion of a Brownian probe through the medium reveals rheological properties. The strength of probe forcing compared to the entropic restoring force defines a Peclet number, Pe. In the absence of hydrodynamics, the first normal stress difference and the osmotic pressure scale as Pe4 and Pe2 respectively when probe forcing is weak, and uniformly as Pe for strong probe forcing. As hydrodynamics become important, interparticle forces give way to lubrication interactions. Hydrodynamic coupling leads to a new low-Pe scaling of the first normal stress difference and the osmotic pressure as Pe2, and high-Pe scaling as Peδ, where 0.799 <= δ <= 1 as hydrodynamics vary from strong to weak. For the entire range of the strength of hydrodynamic interactions and probe forcing, the new phenomenological theory is shown to agree with standard micromechanical definitions of the stress. We further draw a connection between the stress and the energy storage in a suspension, and the entropic nature of such storage is identified.

  16. Assessment of the Pozzolanic Activity of a Spent Catalyst by Conductivity Measurement of Aqueous Suspensions with Calcium Hydroxide

    Sergio Velázquez

    2014-03-01

    Full Text Available The pozzolanic activity of the spent catalyst produced by fluid catalytic cracking (FCC has been studied by various methods in recent years. However, no quick and easy method has been reported for this activity based on the associated studies. In this work, the pozzolanic activity of a spent catalyst was investigated by measuring its electrical conductivity in aqueous suspensions of pozzolan/calcium hydroxide. The behavior of the FCC catalyst residue was compared to that of reactive and inert materials of similar chemical compositions. Further, the influence of temperature on the suspension was studied, and also, a new method was proposed in which the pozzolan/calcium hydroxide ratio was varied (with the initial presence of solid Ca(OH2 in the system. It was concluded that the method is effective, fast and simple for evaluating the high reactivity of the catalyst. Therefore, this method is an alternative for the evaluation of the reactivity of pozzolanic materials.

  17. Comparison of digital controllers used in magnetic suspension and balance systems

    Kilgore, William A.

    1990-01-01

    Dynamic systems that were once controlled by analog circuits are now controlled by digital computers. Presented is a comparison of the digital controllers presently used with magnetic suspension and balance systems. The overall responses of the systems are compared using a computer simulation of the magnetic suspension and balance system and the digital controllers. The comparisons include responses to both simulated force and position inputs. A preferred digital controller is determined from the simulated responses.

  18. SEMI-ACTIVE CONTROL OF VEHICLE SUSPENSION WITH MAGNETO-RHEOLOGICAL DAMPERS PART Ⅱ——EVALUATION OF SUSPENSION PERFORMANCE

    WANG Enrong; YING Liang; WANG Wanjun; RAKHEJA Subhash; SU Chunyi

    2008-01-01

    The design and analysis of an intelligent vehicle suspension with MR dampers should address hybrid semi-active control goals, such as rejection of current-switching discontinuity and MR-damper hysteresis, asymmetric damping from the symmetric MR-damper design, robustness on the vehicle operation parameter uncertainties and consideration of essential multiple suspension goals. Following the proposed skyhook-based asymmetric semi-active controller (Part Ⅰ) for achieving the above goals, herein, a set of suspension performance measures and three kinds of varying amplitude harmonic, rounded pulse and really measured random excitations are systematically defined, and the sensitivity of quarter-vehicle MR-suspension performance to variations in operating conditions is thoroughly analyzed. The results illustrate that the proposed skyhook-based semi-active MR-suspension in the asymmetric mode yields relatively superior dynamic responses to meet the multiple suspension performances of ride, rattle space, road-holding and dynamic tire force transmitted to the pavement, and has desirable robustness on variations in operating conditions of vehicle load and speed and the road roughness.

  19. Potential benefits of magnetic suspension and balance systems

    Lawing, Pierce L.; Dress, David A.; Kilgore, Robert A.

    1987-01-01

    The potential of Magnetic Suspension and Balance Systems (MSBS) to improve conventional wind tunnel testing techniques is discussed. Topics include: elimination of model geometry distortion and support interference to improve the measurement accuracy of aerodynamic coefficients; removal of testing restrictions due to supports; improved dynamic stability data; and stores separation testing. Substantial increases in wind tunnel productivity are anticipated due to the coalescence of these improvements. Specific improvements in testing methods for missiles, helicopters, fighter aircraft, twin fuselage transports and bombers, state separation, water tunnels, and automobiles are also forecast. In a more speculative vein, new wind tunnel test techniques are envisioned as a result of applying MSBS, including free-flight computer trajectories in the test section, pilot-in-the-loop and designer-in-the-loop testing, shipboard missile launch simulation, and optimization of hybrid hypersonic configurations. Also addressed are potential applications of MSBS to such diverse technologies as medical research and practice, industrial robotics, space weaponry, and ore processing in space.

  20. Hysteresis-induced bifurcation and chaos in a magneto-rheological suspension system under external excitation

    Hailong, Zhang; Enrong, Wang; Fuhong, Min; Ning, Zhang

    2016-03-01

    The magneto-rheological damper (MRD) is a promising device used in vehicle semi-active suspension systems, for its continuous adjustable damping output. However, the innate nonlinear hysteresis characteristic of MRD may cause the nonlinear behaviors. In this work, a two-degree-of-freedom (2-DOF) MR suspension system was established first, by employing the modified Bouc-Wen force-velocity (F-v) hysteretic model. The nonlinear dynamic response of the system was investigated under the external excitation of single-frequency harmonic and bandwidth-limited stochastic road surface. The largest Lyapunov exponent (LLE) was used to detect the chaotic area of the frequency and amplitude of harmonic excitation, and the bifurcation diagrams, time histories, phase portraits, and power spectrum density (PSD) diagrams were used to reveal the dynamic evolution process in detail. Moreover, the LLE and Kolmogorov entropy (K entropy) were used to identify whether the system response was random or chaotic under stochastic road surface. The results demonstrated that the complex dynamical behaviors occur under different external excitation conditions. The oscillating mechanism of alternating periodic oscillations, quasi-periodic oscillations, and chaotic oscillations was observed in detail. The chaotic regions revealed that chaotic motions may appear in conditions of mid-low frequency and large amplitude, as well as small amplitude and all frequency. The obtained parameter regions where the chaotic motions may appear are useful for design of structural parameters of the vibration isolation, and the optimization of control strategy for MR suspension system. Projects supported by the National Natural Science Foundation of China (Grant Nos. 51475246, 51277098, and 51075215), the Research Innovation Program for College Graduates of Jiangsu Province China (Grant No. KYLX15 0725), and the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20131402).

  1. Computation of magnetic suspension of maglev systems using dynamic circuit theory

    He, J. L.; Rote, D. M.; Coffey, H. T.

    1992-01-01

    Dynamic circuit theory is applied to several magnetic suspensions associated with maglev systems. These suspension systems are the loop-shaped coil guideway, the figure-eight-shaped null-flux coil guideway, and the continuous sheet guideway. Mathematical models, which can be used for the development of computer codes, are provided for each of these suspension systems. The differences and similarities of the models in using dynamic circuit theory are discussed in the paper. The paper emphasizes the transient and dynamic analysis and computer simulation of maglev systems. In general, the method discussed here can be applied to many electrodynamic suspension system design concepts. It is also suited for the computation of the performance of maglev propulsion systems. Numerical examples are presented in the paper.

  2. Supporting Read/Write Applications in Embedded Real-time Systems via Suspension-aware Analysis

    Tong, Guangmo; Liu, Cong

    2014-01-01

    In many embedded real-time systems, applications often interact with I/O devices via read/write operations, which may incur considerable suspension delays. Unfortunately, prior analysis methods for validating timing correctness in embedded systems become quite pessimistic when suspension delays are present. In this paper, we consider the problem of supporting two common types of I/O applications in a multiprocessor system, that is, write-only applications and read-write applications. For the ...

  3. Assessment of pozzolanic activity using methods based on the measurement of electrical conductivity of suspensions of portlnad cement and pozzolan

    Sergio Velázquez; JOSÉ M. MONZÓ; María V. Borrachero; Jordi Payá

    2014-01-01

    The use of methods based on measuring electrical conductivity to assess pozzolanic activity has recently been used primarily in aqueous suspensions of pozzolan: calcium hydroxide. However, the use of similar methods in suspensions of cement with pozzolans has not been widely studied. This paper proposes a new method for rapid assessment of the pozzolanic activity of mineral admixtures in aqueous cement suspensions. In this study, the conditions for the application of the method were optimized...

  4. Use of MBS (ADAMS / CAR software in simulations of vehicle suspension systems

    Łukasz KONIECZNY

    2014-03-01

    Full Text Available The results of the examination of a vehicle suspension system in the plate position are presented in the paper. The model vehicle is a Fiat Seicento with front independent suspension, McPherson type, with the steering system and with the semi-trailing arm in the rear suspension. Identification of the model was made by comparing the simulation results with the results from the test stand. A multibody model of the vehicle will be used in studies of the impact of shock absorber technical conditions on the dynamics of automotive vehicles.

  5. Modification of a Two Wheeler Suspension System using Fea

    Koneti.Manikanta; N.Amaranageswararao

    2014-01-01

    A spring is defined as an elastic body, whose function is to compress when loaded and to recover its original shape when the load is removed. A spring is a flexible element used to exert a force or a torque and, at the same time, to store energy. The force can be a linear push or pull, or it can be radial. In two wheelers we used to see helical suspension at the front and rear tyres on both sides. But the new model bikes are replacing the rear double suspension with the single hea...

  6. Fundamental connections between models of active suspensions and transversely-isotropic fluids

    Holloway, Craig R; Smith, David J; Green, J Edward F; Clarke, Richard J; Dyson, Rosemary J

    2016-01-01

    Suspensions of self-motile, elongated particles are a topic of significant current interest, exemplifying a form of `active matter'. Examples include self-propelling bacteria, algae and sperm, and artificial swimmers. Ericksen's model of a transversely-isotropic fluid [J. L. Ericksen, Colloid Polym. Sci. 173(2):117-122 (1960)] treats suspensions of non-motile particles as a continuum with an evolving preferred direction; this model describes fibrous materials as diverse as extracellular matrix, textile tufts and cellulose microfibres. Director-dependent effects are incorporated through a modified stress tensor with four viscosity-like parameters. By making fundamental connections with recent models for active suspensions, we establish how these viscosity-like parameters relate to the solvent viscosity, volume fraction of particles and their aspect ratio. This comparison reveals previously neglected components of the stress tensor that significantly alter the rheology; these components should be included in mo...

  7. Transport of a dilute active suspension in pressure-driven channel flow

    Ezhilan, Barath

    2015-01-01

    Confined suspensions of active particles show peculiar dynamics characterized by wall accumulation, as well as upstream swimming, centerline depletion and shear-trapping when a pressure-driven flow is imposed. We use theory and numerical simulations to investigate the effects of confinement and non-uniform shear on the dynamics of a dilute suspension of Brownian active swimmers by incorporating a detailed treatment of boundary conditions within a simple kinetic model where the configuration of the suspension is described using a conservation equation for the probability distribution function of particle positions and orientations, and where particle-particle and particle-wall hydrodynamic interactions are neglected. Based on this model, we first investigate the effects of confinement in the absence of flow, in which case the dynamics is governed by a swimming Peclet number, or ratio of the persistence length of particle trajectories over the channel width, and a second swimmer-specific parameter whose inverse...

  8. Annoyance rate evaluation method on ride comfort of vehicle suspension system

    Tang, Chuanyin; Zhang, Yimin; Zhao, Guangyao; Ma, Yan

    2014-03-01

    The existing researches of the evaluation method of ride comfort of vehicle mainly focus on the level of human feelings to vibration. The level of human feelings to vibration is influenced by many factors, however, the ride comfort according to the common principle of probability and statistics and simple binary logic is unable to reflect these uncertainties. The random fuzzy evaluation model from people subjective response to vibration is adopted in the paper, these uncertainties are analyzed from the angle of psychological physics. Discussing the traditional evaluation of ride comfort during vehicle vibration, a fuzzily random evaluation model on the basis of annoyance rate is proposed for the human body's subjective response to vibration, with relevant fuzzy membership function and probability distribution given. A half-car four degrees of freedom suspension vibration model is described, subject to irregular excitations from the road surface, with the aid of software Matlab/Simulink. A new kind of evaluation method for ride comfort of vehicles is proposed in the paper, i.e., the annoyance rate evaluation method. The genetic algorithm and neural network control theory are used to control the system. Simulation results are obtained, such as the comparison of comfort reaction to vibration environments between before and after control, relationship of annoyance rate to vibration frequency and weighted acceleration, based on ISO 2631/1(1982), ISO 2631-1(1997) and annoyance rate evaluation method, respectively. Simulated assessment results indicate that the proposed active suspension systems prove to be effective in the vibration isolation of the suspension system, and the subjective response of human being can be promoted from very uncomfortable to a little uncomfortable. Furthermore, the novel evaluation method based on annoyance rate can further estimate quantitatively the number of passengers who feel discomfort due to vibration. A new analysis method of vehicle

  9. Establishment of Aquilaria malaccensis Callus, cell suspension and adventitious root systems

    Aquilaria malaccensis is a tropical forest tree from the family Thymelaeaceae, an endangered forest species and was listed in CITES since 1995. Locally known as Pokok Karas, this tree produces agar wood or gaharu, a highly valuable, resinous and fragrant forest product. Karas has been highly recognized for its vast medicinal values and gaharu has been widely use for perfumery, incense and religious purposes. The phyto chemical studies of agar wood showed that Sesqui terpenoid and Phenyl ethy chromone derivatives are the principal compounds that have anti allergic and anti microbe activities. Cell and organ culture systems provide large scale production of biomass and offers feasibilities for the production of secondary metabolites. This paper describes the work done for establishing reproducible systems for callus initiation and production of cell suspension cultures as well as production of adventitious roots that will later be amenable for the production of secondary metabolites of A. malaccensis. Hence, further manipulation with Methyl Jasmonate, a chemical elicitor could be done to induce secondary metabolites using callus, cell suspension and adventitious roots systems. (author)

  10. Fault Detection of Railway Vehicle Suspension Systems Using Multiple-Model Approach

    Hayashi, Yusuke; Tsunashima, Hitoshi; Marumo, Yoshitaka

    This paper demonstrates the possibility to detect suspension failures of railway vehicles using a multiple-model approach from on-board measurement data. The railway vehicle model used includes the lateral and yaw motions of the wheelsets and bogie, and the lateral motion of the vehicle body, with sensors measuring the lateral acceleration and yaw rate of the bogie, and lateral acceleration of the body. The detection algorithm is formulated based on the Interacting Multiple-Model (IMM) algorithm. The IMM method has been applied for detecting faults in vehicle suspension systems in a simulation study. The mode probabilities and states of vehicle suspension systems are estimated based on a Kalman Filter (KF). This algorithm is evaluated in simulation examples. Simulation results indicate that the algorithm effectively detects on-board faults of railway vehicle suspension systems.

  11. Random vibrations of quadratic damping systems. [optimum damping analysis for automobile suspension system

    Sireteanu, T.

    1974-01-01

    An oscillating system with quadratic damping subjected to white noise excitation is replaced by a nonlinear, statistically equivalent system for which the associated Fokker-Planck equation can be exactly solved. The mean square responses are calculated and the optimum damping coefficient is determined with respect to the minimum mean square acceleration criteria. An application of these results to the optimization of automobile suspension damping is given.

  12. Control of vehicle active suspensions by using PD+PI type fuzzy logic with sliding surface

    A PD+PI type fuzzy logic controller with sliding surface is presented in this study. This controller consists of two parts which are PD type and PI type fuzzy logic units. Inputs to those fuzzy logic units are the sliding surface functions and their derivatives. The integrated controller is applied to two degrees of freedom vehicle active suspension model. Both time and frequency domain analysis are evaluated. Numerical results demonstrate that the proposed controller improves the vibration isolation of the vehicle body, without causing a suspension degeneration problem and without degrading road holding very much.

  13. Control method for semi-active suspension based on virtual prototype

    LIANG Yu; LI Jun; CHEN Ji-yan

    2005-01-01

    The simple dynamic model is often adopted to deal with control questions in research on semi-active suspension. The model has more theoretic meanings than authentic ones because of difference between practical and physical models. The virtual prototype has remarkable advantages in its application simulation processes. It is not only faster and more veracious, but also of better visualization of the simulation results.

  14. Neural network compensation of semi-active control for magneto-rheological suspension with time delay uncertainty

    This study presents a new intelligent control method, human-simulated intelligent control (HSIC) based on the sensory motor intelligent schema (SMIS), for a magneto-rheological (MR) suspension system considering the time delay uncertainty of MR dampers. After formulating the full car dynamic model featuring four MR dampers, the HSIC based on eight SMIS is derived. A neural network model is proposed to compensate for the uncertain time delay of the MR dampers. The HSIC based on SMIS is then experimentally realized for the manufactured full vehicle MR suspension system on the basis of the dSPACE platform. Its performance is evaluated and compared under various road conditions and presented in both time and frequency domains. The results show that significant gains are made in the improvement of vehicle performance. Results include a reduction of over 35% in the acceleration peak-to-peak value of a sprung mass over a bumpy road and a reduction of over 24% in the root-mean-square (RMS) sprung mass acceleration over a random road as compared to passive suspension with typical original equipment (OE) shock absorbers. In addition, the semi-active full vehicle system via HSIC based on SMIS provides better isolation than that via the original HSIC, which can avoid the effect of the time delay uncertainty of the MR dampers

  15. Analysis and testing of an integrated semi-active seat suspension for both longitudinal and vertical vibration control

    Bai, Xian-Xu; Jiang, Peng; Pan, Hui; Qian, Li-Jun

    2016-04-01

    An integrated semi-active seat suspension for both longitudinal and vertical vibration control is analyzed and tested in this paper. The seat suspension consists of a switching mechanism transforming both longitudinal and vertical motions into a rotary motion and a real-time damping-controllable system-a rotary magnetorheological (MR) damper working in pure shear mode and its corresponding control system. The switching mechanism employs the parallelogram frames as a motion guide which keeps the seat moving longitudinally and vertically. At the same time, both longitudinal and vertical motions are transformed into a reciprocating rotary motion that is transmitted to the rotary MR damper after an amplification by a gear mechanism. Both the longitudinal and vertical vibrations can be attenuated in real time through controlling the damping force (or torque) of the rotary MR damper. The mathematical model of the seat suspension system is established, simulated, and analyzed. The experimental test based on the test rig in Hefei University of Technology is implemented, and the results of simulation and experimental test are compared and analyzed.

  16. Antidepressant-like activity of flunarizine in modified tail suspension test in rats

    Vinod Shinde

    2015-01-01

    Full Text Available Background: Flunarizine, a Ca 2+ channel blocker, crosses blood brain barrier (BBB, antagonizes calcium influx and interferes with neurotransmitter system. Flunarizine 20 mg/kg exhibited significant antidepressant activity in our previous study using forced swim test (FST in mice, which was contradictory to the findings of other authors. Hence, the present study was designed to strengthen the results of our previous study, using the modified tail suspension test (TST in rats. Aim: Aim of this study was to evaluate the antidepressant activity of flunarizine versus standard antidepressant drug fluoxetine in modified TST in rats. Materials and Methods: The study approved by Institutional Animal Ethics Committee was conducted using 24 adult albino rats (n = 6 in each group. Antidepressant effect of normal saline (0.1 ml/100 g, fluoxetine (10 mg/kg, intraperitoneally (ip, and flunarizine (2 and 10 mg/kg, ip was evaluated by using modified TST in rats. Thirty minutes after administration of all test drugs the duration of immobility was recorded for a period of 5 min in all rats by using modified TST. The data was analyzed by Student′s t-test and one-way analysis of variance (ANOVA and P 0.05. Also, currently used human dose of flunarizine when extrapolated to rats (i. e., 2 mg/kg, ip failed to show significant antidepressant effect in modified TST in rats. Conclusion: The results of the present study indicate antidepressant-like activity of flunarizine.

  17. Further developments relating to the NASA Langley Research Center 13-inch magnetic suspension and balance system

    Britcher, Colin P.

    1991-01-01

    A few specific developments that were undertaken recently to the magnetic suspension and balance system (MSBS) are detailed. The improvements are as follows: modifications to the digital control system to accommodate a modified position sensing system; development of pressure telemetry systems; and revisions to the wind tunnel test section.

  18. Pharmacognostical, Phytochemical and Pharmacological Evaluation for the Antiulcer Activity of Polyherbal Suspension

    AVS. Praveen Kumar; Venu Gopal Jonnalagadda; Jyothi M Joy; Prathyusha. S; Mohana Lakshmi

    2013-01-01

    Objective: From the past few years there is increasing research interest on the natural compounds, due to their wide variety of pharmacological activities. The main aim of the present study was to conduct the evaluation of the Poly herbal suspension (PHS) which includes the preliminary phytochemical screening, standardisation and experimental antiulcer activity. Methods: In this study we conduct the phytochemical screening, standardisation using the high performance thin layer chromatography ...

  19. Applications of Semi-active Hydro-pneumatic Suspension System Based on Fuzzy Control in Articulated Dump Truck%基于模糊控制的半主动油气悬挂系统在铰接式自卸车中的应用

    张春辉; 赵静一; 田兴; 罗利军

    2014-01-01

    Aiming at the phenomenon of rolling over of an articulated dump truck w hen streering around ,a semi-active hydro-pneumatic suspension system was designed based on fuzzy control with the function of anti-roll .The principles of the system were elaborated and the characteristic analysis was made with established mathematical model .It shows that the semi-active hydro-pneumatic sus-pension system meets the basic performance requirements in the condition of non fuzzy control .Based on this ,the anti-roll analysis of the fuzzy control was also made and the simulation was applied using the fuzzy toolbox .Through simulation studies and field trials comparition ,it can be concluded that the suspension system under the way of fuzzy control improves the system’s anti-roll capability effective-ly ,providing a new way of thinking for the domestic research and development of the hydro-pneumatic suspension system .%针对某铰接式自卸车转向过程中出现的侧倾现象,设计了具有抗侧倾功能的模糊控制半主动油气悬挂系统,对其原理进行了阐述并建立数学模型对其特性进行了分析。结果表明,非模糊控制下的半主动油气悬挂系统满足其基本的性能要求。在该基础上针对自卸车某一转向工况下的模糊控制抗侧倾性能进行了分析,并运用Simulink中的fuzzy工具箱进行仿真。仿真分析与现场试验对比研究表明,采用模糊控制方式的油气悬挂系统有效地提高了系统的抗侧倾能力,这为工程机械油气悬挂国产化的研发提供了新的思路。

  20. Development and optimization of the activated charcoal suspension composition based on a mixture design approach

    Ronowicz Joanna

    2015-03-01

    Full Text Available In this study, a new drug product containing activated charcoal was designed and developed. The excipient levels in the pharmaceutical formulation were optimized using a mixture design approach. The adsorption power of the activated charcoal suspension was selected as the critical quality attribute influencing the efficacy of medical treatment. Significant prognostic models (p < 0.05 were obtained to describe in detail the interrelations between excipient levels and the adsorption power of the formulation. Liquid flavour had a critical impact on the adsorption power of the suspension. Formulations containing the largest amount of liquid flavour showed the lowest adsorption power. Sorbitol was not adsorbed onto activated charcoal so strongly as liquid flavour. A slight increase in the content of carboxymethylcellulose sodium led to a marked decrease in adsorption power. The obtained mathematical models and response surface allowed selection of the optimal composition of excipients in a final drug product

  1. Variable Structure Control on Active Suspension of 4 DOF Vehicle Model

    Chuanbo Ren

    2010-12-01

    Full Text Available in this paper, the theory of a variable structure model following control (VSMFC is employed to the design of the controller for an active suspensions of 4-degree-of-freedom (4-DOF automobile model. The sliding mode equation is derived by applying VSMFC theory and the parameters of the switching function are obtained by using the method of pole assignment; a hierarchical algorithm with control variables started in sequence is applied to solve the active force; a method of exponential approach law is used to improve the dynamic performance of the controller. The efficacy of the controller is verified by simulation carried out with the help of Matlab/ Simulink. The results show that the active suspension controller based on VSMFC theory is superior in both robustness and performance.

  2. DESIGN AND APPLICATION OF MAGNETIC BEARING SUSPENSION SYSTEM IN A THREE PHASE INDUCTION MOTOR

    Osman GÜRDAL

    1998-03-01

    Full Text Available The current popularity of suspension and levitation stems no doubt the possibilities in high-speed ground transportation schemes. Although these are both challenging and exciting, there is considerable scope for application of suspension techniques to achieving frictionless bearing. The requirement in this case is often for close tolerances, low power consumption, small airgaps and ingeneral, compactness. Thus, magnetic suspension using DC electromagnets schemes have received more attention than the other techniques of repulsion levitation. Proposed prototype system consists of a conventional stator and its rotor without iron core, set of electromagnets for suspension of rotor shaft and set of compensation circuits feedbacked by optical-transducers. Prototyped system is aimed as a laboratory demonstration tool so there is no challenging to exceed the speeds of 1500 rev/min that is the speed of motor with mechanical bearings. Magnetic bearing suspension system provides a high impact visual demonstration of many principles in undergraduate educational programs in electrical education, e.g., electromagnetic design, PD controlled compensation of a unstable control system and power amplifier design. The system is capable of giving a good comparison between mechanical and magnetic bearing up to speeds 350 rev/min. Power losses without load show about 15% reduction with magnetic bearing. The noise of the motor is also decreased to a low level.

  3. Effective viscosity of active suspensions: Three-dimensional numerical modeling

    Jibuti, Levan,; Zimmermann, Walter; Rafaï, Salima; Peyla, Philippe

    2014-01-01

    A three-dimensional model is proposed for Chlamydomonas Reinhardtii swimming with a breaststroke-like beating of its two flagella. The model reveals unusual angular orbits of the active swimmer under a linear shear flow. Namely, the swimmer sustains orientation transiently across the flow when flagella plane is perpendicular to the shear plane, and amplify the shear-induced rotation along the flow. Such behavior is a result of the interplay between shear-induced deformation and swimmer's peri...

  4. Modeling of Electromagnetic Damper for Automobile Suspension

    Kawamoto, Yasuhiro; Suda, Yoshihiro; Inoue, Hirofumi; Kondo, Takuhiro

    In this paper, the modeling of the electromagnetic damper (EMD) for automobile suspension is presented and the validation of the model is demonstrated by comparing the numerical results with the experimental results obtained using shaker tests. EMD is used as an active suspension and controlled to have output force calculated from velocities of sprung and unsprung masses. The formulation of EMD system for active suspensions is first developed, and the validation of the EMD model is demonstrated by experiments of the EMD for automobile suspensions. The validity of the formulation of the EMD developed in this investigation is shown for the frequency responses as well as energy balance for its active use.

  5. Vibration control of an MR vehicle suspension system considering both hysteretic behavior and parameter variation

    This paper presents vibration control responses of a controllable magnetorheological (MR) suspension system considering the two most important characteristics of the system; the field-dependent hysteretic behavior of the MR damper and the parameter variation of the suspension. In order to achieve this goal, a cylindrical MR damper which is applicable to a middle-sized passenger car is designed and manufactured. After verifying the damping force controllability, the field-dependent hysteretic behavior of the MR damper is identified using the Preisach hysteresis model. The full-vehicle suspension model is then derived by considering vertical, pitch and roll motions. An H∞ controller is designed by treating the sprung mass of the vehicle as a parameter variation and integrating it with the hysteretic compensator which produces additional control input. In order to demonstrate the effectiveness and robustness of the proposed control system, the hardware-in-the-loop simulation (HILS) methodology is adopted by integrating the suspension model with the proposed MR damper. Vibration control responses of the vehicle suspension system such as vertical acceleration are evaluated under both bump and random road conditions

  6. Stability and phase transfer of catalytically active platinum nanoparticle suspensions

    In this work, we present a robust synthesis protocol for platinum nanoparticles that yields a monomodal dispersion of particles that are approximately 100 nm in diameter. We determine that these particles are actually agglomerates of much smaller particles, creating a “raspberry” morphology. We demonstrate that these agglomerates are stable at room temperature for at least 8 weeks by dynamic light scattering. Furthermore, we demonstrate consistent electrocatalytic activity for methanol oxidation. Finally, we quantitatively explore the relationship between dispersion solvent and particle agglomeration; specifically, particles are found to agglomerate abruptly as solvent polarity decreases

  7. GSA-Tuning IPD Control of a Field-Sensed Magnetic Suspension System

    Jen-Hsing Li

    2015-12-01

    Full Text Available The purpose of this paper is to propose a GSA-tuning IPD control technique for magnetic suspension systems. An educational demonstration on a magnetic-field sensed magnetic suspension system is examined for effectiveness. For the magnetic-field sensed magnetic suspension system (FSMSS, the current transducer is employed for measuring the electromagnetic coil current, and a Hall effect device is used for detecting the position of the suspended object. To achieve optimal performance, the gravitational search algorithm (GSA is adopted for tuning the integral-proportional-derivative (IPD controller. The IPD control includes the specified PD controller and an integrator. The specified PD control is employed for stabilizing the inherently unstable FSMSS, whereas the integral control is utilized for eliminating the steady-state error. The GSA can tune the IPD control parameters to enable optimal FSMSS performance. We achieved excellent results from the simulations and hands-on experiments for the proposed control strategies and structures.

  8. Non-dimensionalised closed-form parametric analysis of semi-active vehicle suspensions using a quarter-car model

    Ahmadian, Mehdi; Blanchard, Emmanuel

    2011-02-01

    This article provides a non-dimensionalised closed-form analysis of semi-active vehicle suspensions, using a quarter-car model. The derivation of the closed-form solutions for three indices that can be used for ride comfort, vehicle handling, and stability are presented based on non-dimensionalised suspension parameters. The behaviour of semi-active vehicle suspensions is evaluated using skyhook, groundhook, and hybrid control policies, and compared with passive suspensions. The relationship between vibration isolation, suspension deflection, and road holding is studied, using three performance indices based on the mean square of the sprung mass acceleration, rattle space, and tyre deflection, respectively. The results of the study indicate that the hybrid control policy yields significantly better comfort than a passive suspension, without reducing the road-holding quality or increasing the suspension displacement for typical passenger cars. The results also indicate that for typical passenger cars, the hybrid control policy results in a better compromise between comfort, road holding and suspension travel requirements than both the skyhook and groundhook control methods.

  9. Globally aligned states and hydrodynamic traffic jams in confined active suspensions

    Lefauve, Adrien; Saintillan, David

    2013-01-01

    Strongly confined active liquids are subject to unique hydrodynamic interactions due to momentum screening and lubricated friction by the confining walls. Using numerical simulations, we demonstrate that 2D dilute suspensions of fore-aft asymmetric polar swimmers in a Hele-Shaw geometry can exhibit a rich variety of novel phase behaviors depending on particle shape, including: coherent polarized density waves with global alignment, stationary asters, persistent counter-rotating vortices, dens...

  10. Application of metallic nanoparticle suspensions in advanced cooling systems

    Lee, S.; Choi, S.U.S.

    1996-12-31

    In the development of energy-efficient heat transfer fluids that are required in many cooling applications, low thermal conductivity is a primary limitation. However, it is well known that at room temperature, metals in solid form have orders-of-magnitude higher thermal conductivities than those of fluids. Therefore, the thermal conductivities of fluids that contain suspended solid metallic particles are expected to be significantly enhanced over those of conventional heat transfer fluids. In fact, numerous theoretical and experimental studies of the effective thermal conductivity of dispersions that contain solid particles have been conducted since Maxwell`s theoretical was published more than 100 years ago. However, all of the studies on thermal conductivity of suspensions have been confined to millimeter- or micrometer-sized particles.

  11. A contribution to the investigation of the heat load of shock absorbers of semi-active suspensions in motor vehicles

    Miroslav D. Demić

    2013-10-01

    Full Text Available Dynamic simulation, based on modeling, has a significant role during the process of vehicle development. It is especially important in the first stages of vehicle design, when relevant vehicle parameters are to be defined. Shock absorbers as executive parts of vehicle semi-active suspension systems suffer thermal loads, which may result in damage and degradation of ther characteristics. Therefore,this paper shows an attempt to analyze converting of mechanical work into heat by using the dynamic simulation method. Introduction Shock absorbers are integral elements of semi-active suspension systems for vehicles (hereinafter SASS. They directly affect the active vehicle safety. The role of shock absorbers is to absorb mechanical vibrations transferred from the road and to ensure the safety of passengers in a vehicle. The kinetic energy of vehicle vibrations transforms into mechanical work or heat in shock absorbers. In practice, in the first stage of vehicle development, the shock absorber parameters are chosen from the condition of damping vibrations of vehicles, but their thermal shock loads should be also taken into account. Motor vehicles have complex dynamic characteristics manifested by spatial movement, parameters change during operation, a number of disturbing influences, backlash, friction, hysteresis, etc. The above-mentioned dynamic phenomena, especially vibration, lead to fatigue of driver and users, reduce the life of the vehicle and its systems, etc. The main objective of the system is to reduce the reliance of the above-mentioned negative effects, improving the vehicle behavior on the road and allow the exploitation of vehicles in a wide range of service conditions. Classical systems cannot satisfiy these conditions, so there was a need to introduce new suspension systems with controlled characteristics (briefly called "semi-active", or "active" systems. Oscillatory model of vehicle The differential equations of vibratory motion of

  12. Changes in the cholinergic system of rat sciatic nerve and skeletal muscle following suspension induced disuse

    Gupta, R. C.; Misulis, K. E.; Dettbarn, W. D.

    1984-01-01

    Muscle disused induced changes in the cholinergic system of sciatic nerve, slow twitch soleus (SOL) and fast twitch extensor digitorum longus (EDL) muscle were studied in rats. Rats with hindlimbs suspended for 2 to 3 weeks showed marked elevation in the activity of choline acetyltransferase (ChAT) in sciatic nerve (38%), in SOL (108%) and in EDL (67%). Acetylcholinesterase (AChE) activity in SOL increased by 163% without changing the molecular forms pattern of 4S, 10S, 12S, and 16S. No significant changes in activity and molecular forms pattern of AChE were seen in EDL or in AChE activity of sciatic nerve. Nicotinic receptor binding of 3H-acetylcholine was increased in both muscles. When measured after 3 weeks of hindlimb suspension the normal distribution of type 1 fibers in SOL was reduced and a corresponding increase in type IIa and IIb fibers is seen. In EDL no significant change in fiber proportion is observed. Muscle activity, such as loadbearing, appears to have a greater controlling influence on the characteristics of the slow twitch SOL muscle than upon the fast twitch EDL muscle.

  13. Decoupling Control Design for the Module Suspension Control System in Maglev Train

    Guang He

    2015-01-01

    Full Text Available An engineering oriented decoupling control method for the module suspension system is proposed to solve the coupling issues of the two levitation units of the module in magnetic levitation (maglev train. According to the format of the system transfer matrix, a modified adjoint transfer matrix based decoupler is designed. Then, a compensated controller is obtained in the light of a desired close loop system performance. Optimization between the performance index and robustness index is also carried out to determine the controller parameters. However, due to the high orders and complexity of the obtained resultant controller, model reduction method is adopted to get a simplified controller with PID structure. Considering the modeling errors of the module suspension system as the uncertainties, experiments have been performed to obtain the weighting function of the system uncertainties. By using this, the robust stability of the decoupled module suspension control system is checked. Finally, the effectiveness of the proposed decoupling design method is validated by simulations and physical experiments. The results illustrate that the presented decoupling design can result in a satisfactory decoupling and better dynamic performance, especially promoting the reliability of the suspension control system in practical engineering application.

  14. A dynamic-reliable multiple model adaptive controller for active vehicle suspension under uncertainties

    The inherent uncertainties of vehicle suspension systems challenge not only the capability of ride comfort and handling performance, but also the reliability requirement. In this research, a dynamic-reliable multiple model adaptive (MMA) controller is developed to overcome the difficulty of suspension uncertainties while considering performance and reliability at the same time. The MMA system consists of a finite number of optimal sub-controllers and employs a continuous-time based Markov chain to guide the jumping among the sub-controllers. The failure mode considered is the bottoming and topping of suspension components. A limitation on the failure probability is imposed to penalize the performance of the sub-controllers and a gradient-based genetic algorithm yields their optimal feedback gains. Finally, the dynamic reliability of the MMA controller is approximated by using the integration of state covariances and a judging condition is induced to assert that the MMA system is dynamic-reliable. In numerical simulation, a long scheme with piecewise time-invariant parameters is employed to examine the performance and reliability under the uncertainties of sprung mass, road condition and driving velocity. It is shown that the dynamic-reliable MMA controller is able to trade a small amount of model performance for extra reliability

  15. Wall Sampling of Suspensions from Liquid-solid Systems

    Stipisic, R.

    2008-07-01

    Full Text Available The problem of an adequate sampling from slurry handling equipment is present in many branches of the chemical and related industries. It is often very important to know the solid concentration and the particle size distribution in the apparatus of this kind, in order to control and operate them. For this purpose, wall sampling is widely adopted in industrial practice for its simplicity and versatility. Serious errors in measuring solids concentration can arise from unsuitable sampling. This work reports the main factors that may cause these deviations from ideal wall sampling during work with slurry handling equipment. Up to now, some authors have thoroughly studied the problem of isokinetic and anisokinetic sampling from slurry pipelines, both theoretically and experimentally. However, little work was dedicated to the withdrawal of solid suspensions from stirred vessels. The main sources of sampling errors occur because of particle inertia, particle bouncing effects and flow structure ahead of the sampling device. The results of experimental work of different authors indicate that the solid concentration in the sample, i. e. sampling efficiency, depends strongly on the sample tube design, withdrawal velocity and sampling device location as well.

  16. Eddy Current Influences on the Dynamic Behaviour of Magnetic Suspension Systems

    Britcher, Colin P.; Bloodgood, Dale V.

    1998-01-01

    This report will summarize some results from a multi-year research effort at NASA Langley Research Center aimed at the development of an improved capability for practical modelling of eddy current effects in magnetic suspension systems. Particular attention is paid to large-gap systems, although generic results applicable to both large-gap and small-gap systems are presented. It is shown that eddy currents can significantly affect the dynamic behavior of magnetic suspension systems, but that these effects can be amenable to modelling and measurement. Theoretical frameworks are presented, together with comparisons of computed and experimental data particularly related to the Large Angle Magnetic Suspension Test Fixture at NASA Langley Research Center, and the Annular Suspension and Pointing System at Old Dominion University. In both cases, practical computations are capable of providing reasonable estimates of important performance-related parameters. The most difficult case is seen to be that of eddy currents in highly permeable material, due to the low skin depths. Problems associated with specification of material properties and areas for future research are discussed.

  17. The design and testing of the Gravity Probe B suspension and charge control systems

    Buchman, Saps; Bencze, William; Brumley, Robert; Clarke, Bruce; Keiser, G. M.

    1998-12-01

    The Relativity Mission Gravity Probe B (GP-B), is designed to verify two rotational effects predicted by gravitational theory. The GP-B gyroscopes (which also double as drag free sensors) are suspended electrostatically, their position is determined by capacitative sensing, and their charge is controlled using electrons generated by ultraviolet photoemission. The main suspension system is digitally controlled, with an analog backup system. Its functional range is 10 m/s2 to 10-7 m/s2. The suspension system design is optimized to be compatible with gyroscope Newtonian drift rates of less than 0.1 marcsec/year (3×10-12 deg/hr), as well as being compatible with the functioning of an ultra low noise dc SQUID magnetometer. Testing of the suspension and charge management systems is performed on the ground using flight gyroscopes, as well as a gyroscope simulator designed to verify performance over the entire functional range. We describe the design and performance of the suspension, charge management, and gyroscope simulator systems.

  18. A forecast of new test capabilities using Magnetic Suspension and Balance Systems

    Lawing, Pierce L.; Johnson, William G., Jr.

    1988-01-01

    This paper outlines the potential of Magnetic Suspension and Balance System (MSBS) technology to solve existing problems related to support interference in wind tunnels. Improvement of existing test techniques and exciting new techniques are envisioned as a result of applying MSBS. These include improved data accuracy, dynamic stability testing, two-body/stores release testing, and pilot/designer-in-the-loop tests. It also discusses the use of MSBS for testing exotic configurations such as hybrid hypersonic vehicles. A new facility concept that combines features of ballistic tubes, magnetic suspension, and cryogenic tunnels is described.

  19. SEMI-ACTIVE CONTROL OF VEHICLE SUSPENSION WITH MAGNETO-RHEOLOGICAL DAMPERS:PART III——EXPERIMENTAL VALIDATION

    WANG Enrong; YING Liang; WANG Wanjun; RAKHEJA Subhash; SU Chunyi

    2008-01-01

    A hardware-in-the-loop (HIL) test and simulation platform is developed in the laboratory, so as to validate the performance characteristics of the proposed skyhook-based asymmetric semi-active controller in Part I, and examine the validity of the proposed MR-damper model in a system surrounding. A real-time monitor is designed to assess and monitor the responses of the quarter-vehicle model in the HIL platform, and to select the excitation, controller synthesis, and the output displays. A drive current circuit hardware employing PID feedback technique is developed to compensate for the time delays from the servo-controller and drive current circuit, in which a small resistance is integrated in the current amplifier circuit to provide the feedback signal. The experiments were performed to measure the responses of the quarter-vehicle MR-suspension models with fixed current and the proposed semi-active MR-damping variations, under harmonic, rounded pulse and random road excitations. The measured data were compared with the corresponding model results to examine the model and controller validity, and revealed generally good agreements in the model and tested results and very little sensitivity of the tested responses to variations in the sprung mass. The HIL test results validate the effectiveness of the proposed skyhook-based semi-active asymmetric controller and its high robustness against the vehicle load variations in view of the intelligent vehicle suspension design.

  20. Effect of corticosteroid binding proteins on the steroidogenic activity of bovine adrenocortical cell suspensions.

    Basset, M; Rostaing-Metz, B; Chambaz, E M

    1982-07-01

    The possible role of steroid binding proteins in the hormonal secretion process of a steroidogenic tissue was examined using bovine adrenocortical cell suspensions, either under basal conditions or in the presence of half-maximally active concentration (1 x 10(-9) M) of synthetic adrenocorticotropic hormone (ACTH). Three types of plasma cortisol binding proteins were used, namely bovine serum albumine (BSA), purified transcortin (CBG) and purified anticortisol immunoglobulins (IgG). When added to the incubation medium, CBG (at 1 x 10(-10) to 2 x 10(-9) M cortisol binding sites) and anticortisol IgG (at 4.8 x 10(-10) to 3 x 10(-9) M cortisol binding sites) did not influence either the basal nor the ACTH-stimulated net cortisol production of the cell preparations. Whereas crystallized and delipidated BSA showed also no effect, crude commercial BSA preparation (Cohn fraction V) exhibited an ACTH-like cofactor effect which resulted in a marked increase in the net cortisol production by stimulated cells. These observations might be explained by the presence in crude BSA of lipoprotein-cholesterol complexes, possibly acting as an extracellular source of cholesterol available for corticosteroidogenesis. It may be concluded that specific high affinity cortisol binding systems present outside adrenocortical steroidogenic cells do not influence their secretory activity under short term in vitro condition. In addition, it can be stressed that use of ill defined protein preparations (e.g. crude BSA) may lead to artifactual observations in the study of the differentiated functions of isolated steroidogenic cells. PMID:6287106

  1. Application of Magnetic Suspension and Balance Systems to Ultra-High Reynolds Number Facilities

    Britcher, Colin P.

    1996-01-01

    The current status of wind tunnel magnetic suspension and balance system development is briefly reviewed. Technical work currently underway at NASA Langley Research Center is detailed, where it relates to the ultra-high Reynolds number application. The application itself is addressed, concluded to be quite feasible, and broad design recommendations given.

  2. Active suspension control of a one-wheel car model using single input rule modules fuzzy reasoning and a disturbance observer

    YOSHIMURA Toshio; TERAMURA Itaru

    2005-01-01

    This paper presents the construction of an active suspension control of a one-wheel car model using fuzzy reasoning and a disturbance observer. The one-wheel car model to be treated here can be approximately described as a nonlinear two degrees of freedom system subject to excitation from a road profile. The active control is designed as the fuzzy control inferred by using single input rule modules fuzzy reasoning, and the active control force is released by actuating a pneumatic actuator. The excitation from the road profile is estimated by using a disturbance observer, and the estimate is denoted as one of the variables in the precondition part of the fuzzy control rules. A compensator is inserted to counter the performance degradation due to the delay of the pneumatic actuator. The experimental result indicates that the proposed active suspension system improves much the vibration suppression of the car model.

  3. An efficient recursive least square-based condition monitoring approach for a rail vehicle suspension system

    Liu, X. Y.; Alfi, S.; Bruni, S.

    2016-06-01

    A model-based condition monitoring strategy for the railway vehicle suspension is proposed in this paper. This approach is based on recursive least square (RLS) algorithm focusing on the deterministic 'input-output' model. RLS has Kalman filtering feature and is able to identify the unknown parameters from a noisy dynamic system by memorising the correlation properties of variables. The identification of suspension parameter is achieved by machine learning of the relationship between excitation and response in a vehicle dynamic system. A fault detection method for the vertical primary suspension is illustrated as an instance of this condition monitoring scheme. Simulation results from the rail vehicle dynamics software 'ADTreS' are utilised as 'virtual measurements' considering a trailer car of Italian ETR500 high-speed train. The field test data from an E464 locomotive are also employed to validate the feasibility of this strategy for the real application. Results of the parameter identification performed indicate that estimated suspension parameters are consistent or approximate with the reference values. These results provide the supporting evidence that this fault diagnosis technique is capable of paving the way for the future vehicle condition monitoring system.

  4. Antidepressant-like activity of liposomal formulation containing nimodipine treatment in the tail suspension test, forced swim test and MAOB activity in mice.

    Moreno, Lina Clara Gayoso E Almendra Ibiapina; Rolim, Hercília Maria Lins; Freitas, Rivelilson Mendes; Santos-Magalhães, Nereide Stela

    2016-09-01

    Previous studies have shown that intracellular calcium ion dysfunction may be an etiological factor in affective illness. Nimodipine (NMD) is a Ca(2+) channel blocker that has been extensively investigated for therapy of central nervous system (CNS) disorders. In this work, we have evaluated the antidepressant-like activity of nimodipine encapsulated into liposomes (NMD-Lipo) in mice through tail suspension and forced swim assays, as well as MAOB activity. During the tail suspension test, the administration of NMD-Lipo at 0.1, 1 and 10mg/kg was able to promote a reduction in the immobility time of animals greater than the positive control (imipramine). In the forced swim test, the immobility time of mice treated with NMD-Lipo was reduced. This reduction was significantly greater than that found in the animals treated with imipramine and paroxetine. This may suggest that NMD-Lipo provides more antidepressant-like activity than in positive controls. The groups that received a combination of liposomal NMD and antidepressant drugs showed lower immobility time than the groups, which were treated only with imipramine or paroxetine. The mice treated with the combination of NMD-Lipo and reserpine presented an increase in the time of immobility compared with animals treated only with NMD-Lipo. There was a significant decrease in MAOB activity in animals treated with NMD-Lipo compared with untreated animals. The results of the tail suspension test, forced swim test and MAOB activity suggested that the antidepressant activity of NMD-Lipo may be related to an increase in the cerebral monoamine concentrations. PMID:27270234

  5. Magnetic suspension and balance system (MSBS) advanced study.I - System design

    Boom, Roger W.; Abdelsalam, Mostafa K.; Eyssa, Yehia M.; Mcintosh, Glen E.

    1987-01-01

    A magnetic suspension and balance system is designed to support models of aircraft or other objects in wind tunnels by means of magnetic forces. Major design improvements have been achieved, resulting in reductions of the system size, weight, and cost. These improvements are due to: (1) the use of holmium in the model core to increase its magnetic moment, (2) the use of a powerful new permanent magnet material in the model wings, (3) a new arrangement for the roll coils, and (4) the use of a nonmetallic structure to eliminate eddy current losses. The conceptual design of the holmium core superconductive solenoid and of the new permanent magnet wing assembly is described in detail. The discussion includes comparisons of the pole strengths for different model core magnets, the design of a superconducting solenoid and cryostat, and the analysis of model wing magnetic requirements.

  6. Hybrid modelling and damping collaborative optimisation of Five-suspensions for coupling driver-seat-cab system

    Zhao, Leilei; Zhou, Changcheng; Yu, Yuewei; Yang, Fuxing

    2016-05-01

    For the complex structure and vibration characteristics of coupling driver-seat-cab system of trucks, there is no damping optimisation theory for its suspensions at present, which seriously restricts the improvement of vehicle ride comfort. Thus, in this paper, the seat suspension was regarded as 'the fifth suspension' of cab, the 'Five-suspensions' for this system was proposed. Based on this, using the mechanism modelling method, a 4 degree-of-freedom coupling driver-seat-cab system model was presented; then, by the tested cab suspensions excitation and seat acceleration response, its parameters identification mathematical model was established. Based on this, taking optimal ride comfort as target, its damping collaborative optimisation mathematical model was built. Combining the tested signals and a simulation model with the mathematical models of parameters identification and damping collaborative optimisation, a complete flow of hybrid modelling and damping collaborative optimisation of Five-suspensions was presented. With a practical example of seat and cab system, the damping parameters were optimised and validated by simulation and bench test. The results show that the model and method proposed are correct and reliable, providing a valuable reference for the design of seat suspension and cab suspensions.

  7. A high-force controllable MR fluid damper-liquid spring suspension system

    Raja, Pramod; Wang, Xiaojie; Gordaninejad, Faramarz

    2014-01-01

    The goal of the present research is to investigate the feasibility of incorporating a liquid spring in a semi-active suspension system for use in heavy off-road vehicles. A compact compressible magneto-rheological (MR) fluid damper-liquid spring (CMRFD-LS) with high spring rate is designed, developed and tested. Compressible MR fluids with liquid spring and variable damping characteristics are used. These fluids can offer unique functions in reducing the volume/weight of vehicle struts and improving vehicle dynamic stability and safety. The proposed device consists of a cylinder and piston-rod arrangement with an internal annular MR fluid valve. The internal pressures in the chambers on either side of the piston develop the spring force, while the pressure difference across the MR valve produces the damping force, when the fluid flows through the MR valve. Harmonic characterization of the CMRFD-LS is performed and the force-displacement results are presented. A fluid-mechanics based model is also developed to predict the performance of the system at different operating conditions and compared to the experimental results. Good agreement between the experimental results and theoretical predictions has been achieved.

  8. A high-force controllable MR fluid damper–liquid spring suspension system

    The goal of the present research is to investigate the feasibility of incorporating a liquid spring in a semi-active suspension system for use in heavy off-road vehicles. A compact compressible magneto-rheological (MR) fluid damper–liquid spring (CMRFD–LS) with high spring rate is designed, developed and tested. Compressible MR fluids with liquid spring and variable damping characteristics are used. These fluids can offer unique functions in reducing the volume/weight of vehicle struts and improving vehicle dynamic stability and safety. The proposed device consists of a cylinder and piston–rod arrangement with an internal annular MR fluid valve. The internal pressures in the chambers on either side of the piston develop the spring force, while the pressure difference across the MR valve produces the damping force, when the fluid flows through the MR valve. Harmonic characterization of the CMRFD–LS is performed and the force–displacement results are presented. A fluid-mechanics based model is also developed to predict the performance of the system at different operating conditions and compared to the experimental results. Good agreement between the experimental results and theoretical predictions has been achieved. (paper)

  9. Preliminary investigations of design philosophies and features applicable to large magnetic suspension and balance systems

    Britcher, C. P.; Fortescue, P. W.; Allcock, G. A.; Goodyer, M. J.

    1979-01-01

    The technology which is required to allow the principles of magnetic suspension and balance systems (MSBS) to be applied to the high Reynolds number transonic testing of aircraft models is examined. A test facility is presented as comprising a pressurized transonic cryogenic wind tunnel, with the MSBS providing full six degree of freedom control. The electro-magnets which are superconducting and fed from quiet, bipolar power supplies are examined. A model control system having some self adaptive characteristics is discussed.

  10. A Semi-active Control-oriented Damper Model for an Automotive Suspension

    Lozoya-Santos, Jorge De Jesus; Sename, Olivier; Dugard, Luc; Morales-Menéndez, Rubén; Ramirez-Mendoza, Ricardo,

    2010-01-01

    International audience This paper deals with the modelling of a magneto-rheological damper as a component of a quarter-car model. The objective is to provide an analysis of the transient and frequency behavior of the suspension system in order to evaluate the inherent linearities of two identified models: a complex one and a control-oriented one. The models have a common structure but the effect of the current and the dynamic behavior has different principle. The results show that the desi...

  11. Magnetic suspension system for an Annular Momentum Control Device (AMCD)

    1979-01-01

    A technique to control a rim suspended in a magnetic field was developed. A complete system was developed, incorporating a support structure, magnetic actuators, a rim drive mechanism, an emergency fail-safe system, servo control system, and control electronics. Open loop and closed loop response of the system at zero speed and at 500 revolutions per minute (r/min) of the rim was obtained and analyzed. The rim was then dynamically balanced and a rim speed of 725 r/min was achieved. An analog simulation of the hardware was developed and tested with the actual control electronics connected to the analog computer. The system under development is stable at rim speeds below 700 r/min. Test results indicate that the rim under test is not rigid. The rim has a warp and a number of binding modes which prevented achievement of higher speeds. Further development efforts are required to achieve higher rim speeds.

  12. Vehicle height and posture control of the electronic air suspension system using the hybrid system approach

    Sun, Xiaoqiang; Cai, Yingfeng; Chen, Long; Liu, Yanling; Wang, Shaohua

    2016-03-01

    The electronic air suspension (EAS) system can improve ride comfort, fuel economy and handling safety of vehicles by adjusting vehicle height. This paper describes the development of a novel controller using the hybrid system approach to adjust the vehicle height (height control) and to regulate the roll and pitch angles of the vehicle body during the height adjustment process (posture control). The vehicle height adjustment system of EAS poses challenging hybrid control problems, since it features different discrete modes of operation, where each mode has an associated linear continuous-time dynamic. In this paper, we propose a novel approach to the modelling and controller design problem for the vehicle height adjustment system of EAS. The system model is described firstly in the hybrid system description language (HYSDEL) to obtain a mixed logical dynamical (MLD) hybrid model. For the resulting model, a hybrid model predictive controller is tuned to improve the vehicle height and posture tracking accuracy and to achieve the on-off statuses direct control of solenoid valves. The effectiveness and performance of the proposed approach are demonstrated by simulations and actual vehicle tests.

  13. Assessment of Pozzolanic Activity Using Methods Based on the Measurement of Electrical Conductivity of Suspensions of Portland Cement and Pozzolan

    Sergio Velázquez

    2014-11-01

    Full Text Available The use of methods based on measuring electrical conductivity to assess pozzolanic activity has recently been used primarily in aqueous suspensions of pozzolan: calcium hydroxide. However, the use of similar methods in suspensions of cement with pozzolans has not been widely studied. This paper proposes a new method for rapid assessment of the pozzolanic activity of mineral admixtures in aqueous cement suspensions. In this study, the conditions for the application of the method were optimized, such as time, temperature, w/c ratio and dosage procedure. Finally, results are presented from the application of this method for characterizing the pozzolanic activity of the spent catalytic cracking catalyst. These results corroborate as previously reported, namely the high reactivity of this pozzolan obtained by other methods, such as thermogravimetry or evolution of the mechanical strength. In addition, the pozzolanic activity of the catalyst was compared with other pozzolans such as metakaolin and silica fume.

  14. Global attractors for the coupled suspension bridge system with temperature

    Dell'Oro, Filippo; Giorgi, C.

    2016-01-01

    Roč. 39, č. 4 (2016), s. 864-875. ISSN 0170-4214 Institutional support: RVO:67985840 Keywords : absorbing set * coupled bridge system * global attractor Subject RIV: BA - General Mathematics Impact factor: 0.918, year: 2014 http://onlinelibrary.wiley.com/doi/10.1002/mma.3526/abstract

  15. Discrete-time sliding mode control for MR vehicle suspension system

    This paper presents control performance of a full-vehicle suspension system featuring magnetorheological (MR) dampers via a discrete-time sliding mode control algorithm (DSMC). A cylindrical MR damper is designed by incorporating Bingham model of the MR fluid and the field-dependent damping characteristics of the MR damper are evaluated. A full-vehicle suspension model installed with independent four MR dampers is constructed and the governing equations which include vertical, pitch and roll motion are derived. A discrete-time control model is established with considering system uncertainties and a discrete-time sliding mode controller which has inherent robustness to model uncertainty and external disturbance is formulated. Vibration control performances under bump excitation are evaluated and presented.

  16. Study on needs for a magnetic suspension system operating with a transonic wind tunnel

    Martindale, W. R.; Butler, R. W.; Starr, R. F.

    1985-01-01

    The U.S. aeronautical industry was surveyed to determine if current and future transonic testing requirements are sufficient to justify continued development work on magnetic suspension and balance systems (MSBS) by NASA. The effort involved preparation of a brief technical description of magnetic suspension and balance systems, design of a survey form asking specific questions about the role of the MSBS in satisfying future testing requirements, selecting nine major aeronautics companies to which the description and survey forms were sent, and visiting the companies and discussing the survey to obtain greater insight to their response to the survey. Evaluation and documentation of the survey responses and recommendations which evolved from the study are presented.

  17. The mathematical model and simulation of the electrostatic suspension system in the vertical direction

    Ku Shaoping; Zhou Zude; Hu Yefa

    2008-01-01

    In order to research the vibration law of electrostatic suspension systems in the vertical direction, the mathe- matical model as a nonlinear differential equation is established. A series of simulation is carried out. The results show that the solution of the differential equation is a periodic function. The amplitude becomes bigger with the original veloc-ity increased. The period becomes smaller with the original velocity increasing. The numerical methods are presented to derive the amplitude and the frequency, and the results coincide with that of the simulation. The condition during which the simple harmonic vibration arises is pointed out. The expressions for the amplitude and the period of simple harmonic vibration are derived respectively, and the results are the same with that of the simulation. This study is helpful for re-searching the vibration characteristics of the electrostatic suspension system. The external disturb should be controlled to lower the amplitude and the frequency of the vibration.

  18. The MIT / NASA Langley Magnetic Suspension/Balance System

    1991-01-01

    A shuttle model is magnetically suspended in the transparent octagonal test section of the MIT / NASA Langley 6 Inch MSBS. Massive power supplies are required to drive electromagnets for model position control. A unique electromagnetic position sensor, similar to a linear variable differential transformer, provides five degrees of freedom for the test model. The low speed (Mach 0.5) wind tunnel was hand crafted from mahogany. Aerodynamic forces on the test model are measured by the proportional electrical current used to hold the model in place. The system was built by MIT in the late sixties and was relocated to Langley in the mid eighties. In a joint effort with Old Dominion University in 1992 the MSBS was used to test the aerodynamics of store separation, simulating a bomb released from an aircraft. The system has been donated to Old Dominion University.

  19. Alternative Suspension System for Space Shuttle Avionics Shelf

    Biele, Frank H., III

    2010-01-01

    Engineers working in the Aerospace field under deadlines and strict budgets often miss the opportunity to design something that is considered new or innovative, favoring instead to use the tried-and-true design over those that may, in fact, be more efficient. This thesis examines an electronic equipment stowage shelf suspended from a frame in the cargo bay (mid fuselage) of the United States Space Transportation System (STS), the Space Shuttle, and 3 alternative designs. Four different designs are examined and evaluated. The first design is a conventional truss, representing the tried and true approach. The second is a cable dome type structure consisting of struts and pre-stressed wiring. The third and fourth are double layer tensegrity systems consisting of contiguous struts of the order k=1 and k=2 respectively.

  20. Alternate suspension system for space shuttle avionics shelf

    Biele, Frank H., III

    This thesis examines an equipment stowage shelf suspended from a frame in the cargo bay (mid fuselage) of the U.S. Space Shuttle, and three alternative designs. The first design is a conventional truss, representing the "tried and true" approach. The second is a cable dome type structure consisting of struts and pre-stressed cables. The third and fourth are double layer tensegrity systems consisting of contiguous struts of the order k=1 and k=2 respectively. The four options are compared to each other with an emphasis placed on weight, size, and approximate cost of each option. Results indicate the 4-Way Double Layer Tensegrity grid utilizing carbon fiber composite cables is the most efficient (lightest weight) tensegrity system, however for this particular application the most cost effective design was proven to be the optimized conventional truss. It was determined that the scale of the structure would have to increase substantially or tensegrity structures complexity must decrease for these alternative systems to compete with conventional designs.

  1. PATHOGEN IMPACT ON THE ACTIVITY DYNAMICS OF POTATO SUSPENSION CELLS EXTRA-CELLULAR PEROXIDASE

    Graskova I.A.

    2005-08-01

    Full Text Available Changes in the activity of extracellular peroxidases were measured in cell suspension cultures of potato infected by Clavibacter michiganensis subsp. sepedonicus (Spieck. et Kotth. Skapt et Burkh. The total extracellular peroxidases activity of the resistant potato variety was higher than that of the sensitive variety both before and after infection. The enzyme of the resistant variety had a рН optimum of 6.2, while that of the sensitive variety was 5.4. Extracellular peroxidases of the sensitive potato variety were activated 10 minutes after infection, and displayed highest activity 1.5-2 hours later. In the resistant variety, peroxidase activity rose sharply in the first minutes of infection, and second peak of activity occurred 1.5-2 hours later. The increase of extracellular peroxidases activity of the sensitive potato variety under pathogenesis is connected with the change of genome expression and synthesis of proteins. The increase of enzyme activity of resistant potato variety in the first moments of infection is not related to proteins synthesis and is apparently conditioned by the change of kinetic parameters.

  2. Lipoxygenase activity and sanguinarine production in cell suspension cultures of California poppy (Eschscholtzia californica CHAM.).

    Kollárová, R; Oblozinský, M; Kováciková, V; Holková, I; Balazová, A; Pekárová, M; Hoffman, P; Bezáková, L

    2014-08-01

    In this study we investigated the influence of biotic elicitor (phytopathogenic fungus Botrytis cinerea) and abiotic elicitors (methyljasmonate [MJ] and salicylic acid [SA]) on lipoxygenase (LOX) activity and sanguinarine production in cell suspension cultures of California poppy (Eschscholtzia californica CHAM.). We have observed different time effects of elicitors (10, 24, 48 and 72 h) on LOX activity and production of sanguinarine in in vitro cultures. All elicitors used in the experiments evidently increased the LOX activity and sanguinarine production in contrast to control samples. The highest LOX activities were determined in samples elicitated by MJ after 48 h and 72 h and the lowest LOX activities (in contrast to control samples) were detected after biotic elicitation by Botrytis cinerea. These activities showed about 50% lower level against the activities after MJ elicitation. The maximal amount of sanguinarine was observed after 48 h in MJ treated cultures (429.91 mg/g DCW) in comparision with control samples. Although all elicitors affect the sanguinarine production, effect of SA and biotic elicitor on sanguinarine accumulation in in vitrocultures was not so significant than after MJ elicitation. PMID:25158577

  3. Drag measurements on a body of revolution in Langley's 13-inch Magnetic Suspension and Balance System

    Dress, David A.

    1988-01-01

    NASA Langley's 13-inch Magnetic Suspension and Balance System (MSBS) has been used to conduct low-speed wind tunnel drag force measurements on a laminar-flow body-of-revolution free of support system interference, in order to verify the drag force measurement capabilities of the MSBS. The drag force calibrations and wind-on repeatability data obtained have verified the design capabilities for this system. A drag-prediction code has been used to assess the MSBS's usefulness in body drag estimation.

  4. Variable structure pantograph mechanism with spring suspension system for comprehensive upper-limb haptic movement training

    Joel C. Perry, PhD

    2011-05-01

    Full Text Available Numerous haptic devices have been developed for upper-limb neurorehabilitation, but their widespread use has been largely impeded because of complexity and cost. Here, we describe a variable structure pantograph mechanism combined with a spring suspension system that produces a versatile rehabilitation robot, called Universal Haptic Pantograph, for movement training of the shoulder, elbow, and wrist. The variable structure is a 5-degree-of-freedom (DOF mechanism composed of 7 joints, 11 joint axes, and 3 configurable joint locks that reduce the number of system DOFs to between 0 and 3. The resulting device has eight operational modes: Arm, Wrist, ISO (isometric 1, ISO 2, Reach, Lift 1, Lift 2, and Steer. The combination of available work spaces (reachable areas shows a high suitability for movement training of most upper-limb activities of daily living. The mechanism, driven by series elastic actuators, performs similarly in all operational modes, with a single control scheme and set of gains. Thus, a single device with minimal setup changes can be used to treat a variety of upper-limb impairments that commonly afflict veterans with stroke, traumatic brain injury, or other direct trauma to the arm. With appropriately selected design parameters, the developed multimode haptic device significantly reduces the costs of robotic hardware for full-arm rehabilitation while performing similarly to that of single-mode haptic devices. We conducted case studies with three patients with stroke who underwent clinical training using the developed mechanism in Arm, Wrist, and/or Reach operational modes. We assessed outcomes using Fugl-Meyer Motor Assessment and Wolf Motor Function Test scores showing that upper-limb ability improved significantly following training sessions.

  5. Dynamics of indole-3-acetic acid oxidase activity in suspension culture of sunflower crown-gall

    Zofia Chirek

    2014-02-01

    Full Text Available IAA oxidase activity was determined in several growth phases of a suspension culture of sunflower crown-gall. During the short phase of intensive growth (zero passage - PO a negative correlation was noted between enzymatic activity and the rate of growth. IAA oxidase activity increased to a certain level is not a factor limiting cell division. For protraction of the phase of intensive growth (first passage - P1, however, a decrease in the activity of this enzyme seems indispensable. IAA oxidase activity in the tested culture is under the control of inhibitors present in the cells and medium. High enzyme inhibition was observed in PO cells during the phase, of intensive growth and in P1 at the beginning and in the middle part of this phase. These results suggest' that the -auxin level determined in earlier studies in sunflower crown-gall culture is controlled by the IAA oxidase set. During the long phase of intensive growth (P1 this control is of negative feedback type.

  6. 磁流变减振器半主动悬架的系统时滞%Time Lag of Magnetorheological Damper Semi-active Suspensions

    赵剡水; 周孔亢; 李仲兴; 姚斌

    2009-01-01

    Time delay causes unsynchronized controllable damping force of magnetorheological damper, which degrades the performance and stability of vehicle semi-active suspension, therefore time-delay problem is one of the hot spots of research on semi-active suspension. Based on the response characteristics of RD-1005-3 magnetorheological damper and the theoretical analysis of critical time delay of semi-active suspension, the mathematical model and the transfer function of magnetorheological semi-active suspension with time delay are established, and the effect of time delay on the amplitude frequency characteristics of suspension is analyzed. Through analyzing the numerical solution of critical time delay, theoretical basis is provided for the research on time-delay of control system of magnetorheological semi-active suspension. Based on fuzzy control strategy, Smith forecasting compensation control is used to carry out compensation of time delay for the system, and simulation analysis is carded out in Matlab. Bench test is carried out for the built single mass magnetorheological semi-active suspension system, and the data of simulation and test show that the time delay compensated system improves the performance of suspensions well.%时滞导致磁流变减振器可控阻尼力的不同步,降低了车辆半主动悬架的性能及其稳定性,因此时滞问题是近年来半主动悬架的研究热点之一.基于RD-1005-3磁流变减振器的响应特性,在半主动悬架临界时滞理论分析的基础上,建立含有时滞的磁流变半主动悬架的数学模型与传递函数,分析时滞对悬架幅频特性的影响:通过对临界时滞数值解的分析,为磁流变半主动悬架控制系统的时滞研究提供理论依据.在模糊控制策略的基础上,运用Smith预估补偿控制对系统进行时滞补偿,并在Matlab中进行仿真分析.对搭建的单质量磁流变半主动悬架系统进行台架试验,仿真和试验数

  7. On the Massive Antenna Suspension System in the Brazilian Gravitational Wave Detector SCHENBERG

    da Silva Bortoli, Fabio; Frajuca, Carlos; de Sousa, Sergio Turano; de Waard, Arlette; Magalhaes, Nadja Simao; de Aguiar, Odylio Denys

    2016-06-01

    SCHENBERG is a resonant-mass gravitational wave detector built in Brazil. Its spherical antenna, weighting 1.15 t, is connected to the outside world by a suspension system whose main function is to attenuate the external seismic noise. In this work, we report how the system was modeled using finite elements method. The model was validated on experimental data. The simulation showed that the attenuation obtained is of the order of 260 dB, which is sufficient for decreasing the seismic noise below the level of the thermal noise of the detector operating at 50 mK.

  8. Coordinate system applied to magnetic suspension project between Shanghai and Hangzhou

    Yimin SHI; Lihua WANG; Yan LUO

    2008-01-01

    In order to satisfy the requirement for route location of a magnetic suspension project between Shanghai and Hangzhou, this paper proposes to adopt a new form of geodetic coordinate system, which is defined by meridians and parallel circles but with two coordinate parameters expressed by length. Not only the coordinate systems for route location along the whole line can be unified, but also the precision of lengths and angles obtained from simple formulas are very high and there are not any map projection distortions. This has been proven by calculation.

  9. Theoretical and FEM analysis of suspension and propulsion system with HTS hybrid electromagnets in an EMS Maglev model

    We examine levitation and propulsion forces of the proto-type maglev vehicle system based on 3D FEM. The levitation force increases over 15% due to AC current of the guideway. The levitation force by HTS electromagnet (EM) and AC current is larger over 30% than that of only HTS EM. We have been constructed a proto-type electromagnetic suspension (EMS) based maglev vehicle system. The maglev concept utilizes magnetic forces for noncontact suspension, guidance and propulsion. The suspension system with high temperature superconducting (HTS) hybrid electromagnet (EM) is composed of HTS coils and normal coils, which consume little power to keep large suspension gap. The magnetic forces realize to guide the vehicle, propel the vehicle along the guide-way and assist in braking action. The proto-type EMS-based Maglev model is designed to keep the suspension gap of 20 mm. This paper presents the theoretical analysis of the maglev vehicle based on the EMS model to obtain the designing parameters for levitation and propulsion forces. The magnetic field distributions of the electromagnetic forces with hybrid EM and propulsion stator coils are analyzed based on three dimension (3D) finite element method (FEM) analysis. From the simulation results, appropriately design parameters of the suspension, guidance and propulsion were obtained.

  10. Pharmacognostical, Phytochemical and Pharmacological Evaluation for the Antiulcer Activity of Polyherbal Suspension

    AVS. Praveen Kumar

    2013-09-01

    Full Text Available Objective: From the past few years there is increasing research interest on the natural compounds, due to their wide variety of pharmacological activities. The main aim of the present study was to conduct the evaluation of the Poly herbal suspension (PHS which includes the preliminary phytochemical screening, standardisation and experimental antiulcer activity. Methods: In this study we conduct the phytochemical screening, standardisation using the high performance thin layer chromatography (HPTLC & infra-red spectroscopy (IR. Also, the PHS was evaluated for the acute toxicity and antiulcer activity at 400 mg/kg and 800 mg/kg in adult albino wistar rats induced by the ethanol (1ml/kg, indomethacin (40mg/kg and aspirin (150mg/kg ulcer models. Results: After phytochemical screening, the PHS showed the presence of the terpenoids, flavonoids and tannins which produces antiulcer activity. The therapeutic efficacy achieved at both dose levels of the PHS when compared with the standard sucralfate (100mg/kg showed a significant (P<0.05 antiulcer activity in ethanol induced model, PHS shown a significant reduction (P<0.05 of ulceration when compared with the indomethacin induced control group as that of misoprostol (100 mcg/kg and same as the above it shown the anti-ulcerogenic protection in aspirin induced model, here the standard drug was omeprazole (10 mg/kg. The highly significant antiulcer activity was exhibited at dose level of 800 mg/kg. Conclusion: The results of the present study showed the pronounced anti-ulcerogenic activity of the PHS at the dose of 800 mg/kg after the standard phytochemical and pharmacognostical study.

  11. Double integrating sphere system for optical parameter determination of industrial suspensions

    Keränen, Ville T. J.; Mäkynen, Anssi J.

    2008-06-01

    The main objective of this study was to construct a double integrating sphere system and to verify its performance using Intralipid fat emulsion. The final goal was to be able to determine optical properties of various turbid suspensions with the proposed system. Online measurements even would have been possible as backscattering and forward scattering were measured simultaneously. The measured suspension was injected in a cuvette placed between two integrating spheres and illuminated with a laser through the first sphere. The diameter of the spheres was 8" and the diameter of the sample port could have been varied up to 2.5". The cuvette was made of plastic and optical grade glass and its diameter was sufficient to cover the sample port area. The sample thickness in the measurement cuvette was 5 mm. Optical powers were detected using fiber coupled photodiodes. There was one diode for each sphere and one for the unscattered light at the opposite end of the sphere system facing towards the laser. The measured optical powers were converted to absorption coefficient, scattering coefficient and if possible to anisotropy using an inverse adding-doubling method. The results measured for the Intralipid using the described system corresponded with those documented in published literature. A number of pulp samples with unknown optical properties were measured with encouraging results. However, the differences between different pulps and fillers are so small that, in the future, the focus will be in error source elimination to achieve reasonable accuracy.

  12. Fatigue Life Prediction of Multi Leaf Spring used in the Suspension System of Light Commercial Vehicle

    V.K.Aher; R. A. Gujar; Wagh, J. P.; P.M.Sonawane

    2012-01-01

    The Leaf spring is widely used in automobiles and one of the components of suspension system. It needs to have high fatigue life. As a general rule, the leaf spring is regarded as a safety component as failure could lead to severe accidents. The purpose of this paper is to predict the fatigue life of steel leaf spring along with analytical stress and deflection calculations. This present work describes static and fatigue analysis of a steel leaf spring of a light commercial vehicle (LCV). Th...

  13. High angle of attack position sensing for the Southampton University magnetic suspension and balance system

    Parker, David H.

    1987-01-01

    An all digital five channel position detection system is to be installed in the Southampton University Magnetic Suspension and Balance System (SUMSBS). The system is intended to monitor a much larger range of model pitch attitudes than has been possible hitherto, up to a maximum of a 90 degree angle of attack. It is based on the use of self-scanning photodiode arrays and illuminating laser light beams, together with purpose built processing electronics. The principles behind the design of the system are discussed, together with the results of testing one channel of the system which was used to control the axial position of a magnetically suspended model in SUMSBS. The removal of optically coupled heave position information from the axial position sensing channel is described.

  14. Superconducting electromagnets for large wind tunnel magnetic suspension and balance systems

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.; Scurlock, R. G.; Wu, Y. Y.; Goodyer, M. J.; Balcerek, K.; Eskins, J.; Britcher, C. P.

    1984-01-01

    A superconducting electromagnetic suspension and balance system for an 8 x 8-ft, Mach 0.9 wind tunnel is presented. The system uses a superconducting solenoid as a model core 70 cm long and with a 11.5 cm OD, and a combination of permanent magnet material in the model wings to produce the required roll torque. The design, which uses an integral cold structure rather than separate cryostats for mounting all control magnets, has 14 external magnets, including 4 racetrack-shaped roll coils. Helium capacity of the system is 3.0 to 3.5 l with idling boiloff rate predicted at 0.147 to 0.2 l/h. The improvements yielded a 50-percent reduction in the system size, weight, and cost.

  15. System concept definition of the Grumman superconducting Electromagnetic Suspension (EMS) Maglev design

    Proise, M.

    1994-01-01

    Grumman, under contract to the Army Corps of Engineers, completed a System Concept Definition (SCD) study to design a high-speed 134 m/s (300 m.p.h.) magnetically levitated (Maglev) transportation system. The primary development goals were to design a Maglev that is safe, reliable, environmentally acceptable, and low-cost. The cost issue was a predominant one, since previous studies have shown that an economically viable Maglev system (one that is attractive to investors for future models of passenger and/or freight transportation) requires a cost that is about $12.4 M/km ($20 Million per mile). The design is based on the electromagnetic suspension (EMS) system using superconducting iron-core magnets mounted along both sides of the vehicle. The EMS system has several advantages compared to the electrodynamic suspension (EDS) Maglev systems such as low stray magnetic fields in the passenger cabin and the surrounding areas, uniform load distribution along the full length of the vehicle, and small pole pitch for smoother propulsion and ride comfort. It is also levitated at all speeds and incorporates a wrap-around design of safer operation. The Grumman design has all the advantages of an EMS system identified above, while eliminating (or significantly improving) drawbacks associated with normal magnet powered EMS systems. Improvements include larger gap clearance, lighter weight, lower number of control servos, and higher off line switching speeds. The design also incorporates vehicle tilt (plus or minus 9 deg) for higher coordinated turn and turn out speed capability.

  16. Developments at M.I.T. related to magnetic model suspension and balance systems for large scale facilities

    Haldeman, C. W.; Way, P.; Kramer, R. A.

    1979-01-01

    The paper deals with magnetic model suspension and balance systems for wind tunnel use. Particular attention is given to the extension of the electromagnetic position sensor (EPS) system producing roll position signals and the ac roll drive system producing closed loop control of rolling moment.

  17. Wind Tunnel Magnetic Suspension and Balance Systems With Transversely Magnetized Model Cores

    Britcher, Colin P.

    1998-01-01

    This paper discusses the possibility of using vertically magnetized model cores for wind tunnel Magnetic Suspension and Balance Systems (MSBS) in an effort to resolve the traditional "roll control" problem. A theoretical framework is laid out, based on previous work related to generic technology development efforts at NASA Langley Research Center. The impact of the new roll control scheme on traditional wind tunnel MSBS configurations is addressed, and the possibility of demonstrating the new scheme with an existing electromagnet assembly is explored. The specific system considered is the ex- Massachusetts Institute of Technology (MIT), ex-NASA, 6-inch MSBS currently in the process of recommissioning at Old Dominion University. This system has a sufficiently versatile electromagnet configuration such that straightforward "conversion" to vertically magnetized cores appears possible.

  18. Energy conservation research of dehumidification system for main cable anticorrosion of suspension bridge

    Chen Ce; Fan Liangkai; Feng Zhaoxiang; Pen Guanzhong

    2011-01-01

    The necessity of the main cable anticorrosion for suspension bridge is described, and operating principles and composition of main cable dehumidification system are analyzed. An idea using the waste heat of high temperature outlet air of dehumidification system to heat up regeneration air of rotary-type dehumidifier is put forward in this paper. The concrete scheme is to install a heat exchanger on air-out pipeline of roots blower and air-in pipeline of regeneration electric heater of rotary dehumidifier. Air preheated by the heat exchanger enters regeneration electric heater of rotary-type dehumidifier. Energy conservation of main cable dehumidification system for the Yangtze River highway bridge is calculated, and the results show that energy conservation rate can reach 44 %.

  19. Optimisation of active suspension control inputs for improved vehicle ride performance

    Čorić, Mirko; Deur, Joško; Xu, Li; Tseng, H. Eric; Hrovat, Davor

    2016-07-01

    A collocation-type control variable optimisation method is used in the paper to analyse to which extent the fully active suspension (FAS) can improve the vehicle ride comfort while preserving the wheel holding ability. The method is first applied for a cosine-shaped bump road disturbance of different heights, and for both quarter-car and full 10 degree-of-freedom vehicle models. A nonlinear anti-wheel hop constraint is considered, and the influence of bump preview time period is analysed. The analysis is then extended to the case of square- or cosine-shaped pothole with different lengths, and the quarter-car model. In this case, the cost function is extended with FAS energy consumption and wheel damage resilience costs. The FAS action is found to be such to provide a wheel hop over the pothole, in order to avoid or minimise the damage at the pothole trailing edge. In the case of long pothole, when the FAS cannot provide the wheel hop, the wheel is travelling over the pothole bottom and then hops over the pothole trailing edge. The numerical optimisation results are accompanied by a simplified algebraic analysis.

  20. Smooth Sliding Mode Control for Vehicle Rollover Prevention Using Active Antiroll Suspension

    Duanfeng Chu

    2015-01-01

    Full Text Available The rollover accidents induced by severe maneuvers are very dangerous and mostly happen to vehicles with elevated center of gravity, such as heavy-duty trucks and pickup trucks. Unfortunately, it is hard for drivers of those vehicles to predict and prevent the trend of the maneuver-induced (untripped rollover ahead of time. In this study, a lateral load transfer ratio which reflects the load distribution of left and right tires is used to indicate the rollover criticality. An antiroll controller is designed with smooth sliding mode control technique for vehicles, in which an active antiroll suspension is installed. A simplified second order roll dynamic model with additive sector bounded uncertainties is used for control design, followed by robust stability analysis. Combined with the vehicle dynamics simulation package TruckSim, MATLAB/Simulink is used for simulating experiment. The results show that the applied controller can improve the roll stability under some typical steering maneuvers, such as Fishhook and J-turn. This direct antiroll control method could be more effective for untripped rollover prevention when driver deceleration or steering is too late. It could also be extended to handle tripped rollovers.

  1. Optimization of the linear quadratic regulator (LQR control quarter car suspension system using genetic algorithm

    Mahesh Nagarkar

    2016-04-01

    Full Text Available In this paper, a genetic algorithm (GA based in an optimization approach is presented in order to search the optimum weighting matrix parameters of a linear quadratic regulator (LQR. A Macpherson strut quarter car suspension system is implemented for ride control application. Initially, the GA is implemented with the objective of minimizing root mean square (RMS controller force. For single objective optimization, RMS controller force is reduced by 20.42% with slight increase in RMS sprung mass acceleration. Trade-off is observed between controller force and sprung mass acceleration. Further, an analysis is extended to multi-objective optimization with objectives such as minimization of RMS controller force and RMS sprung mass acceleration and minimization of RMS controller force, RMS sprung mass acceleration and suspension space deflection. For multi-objective optimization, Pareto-front gives flexibility in order to choose the optimum solution as per designer’s need.

  2. Some aspects of wind tunnel magnetic suspension systems with special application at large physical scales

    Britcher, C. P.

    1983-01-01

    Wind tunnel magnetic suspension and balance systems (MSBSs) have so far failed to find application at the large physical scales necessary for the majority of aerodynamic testing. Three areas of technology relevant to such application are investigated. Two variants of the Spanwise Magnet roll torque generation scheme are studied. Spanwise Permanent Magnets are shown to be practical and are experimentally demonstrated. Extensive computations of the performance of the Spanwise Iron Magnet scheme indicate powerful capability, limited principally be electromagnet technology. Aerodynamic testing at extreme attitudes is shown to be practical in relatively conventional MSBSs. Preliminary operation of the MSBS over a wide range of angles of attack is demonstrated. The impact of a requirement for highly reliable operation on the overall architecture of Large MSBSs is studied and it is concluded that system cost and complexity need not be seriously increased.

  3. Progress of magnetic suspension and balance systems for wind tunnels in the USSR

    Kuzin, A. V.; Vyshkov, Y. D.; Shapovalov, G. K.

    1992-01-01

    Magnetic Suspension and Balance Systems (MSBS) for wind tunnels are being developed in order to solve the principal problems of aerodynamics which cannot be solved by conventional means: (1) measurements of aerodynamic loads acting on the aircraft models without the effects of mechanical supporting devices; and (2) the study of base pressure. This paper traces the progress of MSBS for wind tunnels in the Commonwealth of Independent States (CIS). The paper describes electromagnetic configuration, position sensing, and control and calibration systems of two wind tunnel MSBS existing in the CIS. The features of high-angle-of-attack control and roll control are discussed. The results of preliminary experiments on high-angle-of-attack and roll controls, digital control, and aerodynamic testing are also presented.

  4. 75 FR 27847 - Broadengate Systems, Inc., (n/k/a Otter Lake Resources, Inc.); Order of Suspension of Trading

    2010-05-18

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Broadengate Systems, Inc., (n/k/a Otter Lake Resources, Inc.); Order of Suspension of Trading May... accurate information concerning the securities of Broadengate Systems, Inc. (n/k/a Otter Lake...

  5. Structural observation of long-span suspension bridges for safety assessment: implementation of an optical displacement measurement system

    This paper addresses the implementation of an optical displacement measurement system in the observation scenario of a long-span suspension bridge and its contribution for structural safety assessment. The metrological background required for quality assurance of the measurements is described, namely, the system's intrinsic parameterization and integration in the SI dimensional traceability chain by calibration, including its measurement uncertainty assessment

  6. Geophysical exploration of an active pockmark field in the Bay of Concarneau, southern Brittany, and implications for resident suspension feeders

    Baltzer, Agnès; Ehrhold, Axel; Rigolet, Carinne; Souron, Aurélie; Cordier, Céline; Clouet, Hélène; Dubois, Stanislas F.

    2014-06-01

    About a decade ago, a large field of pockmarks (individual features up to 30 m in diameter and tube mats formed by a benthic community of the suspension-feeding amphipod Haploops nirae. The present study complements those findings with subbottom chirp profiles, seabed sonar imagery and ultrasonic backscatter data from the water column acquired in April 2011. Results show that pockmark distribution is influenced by the thickness of Holocene deposits covering an Oligocene palaeo-valley system. Two groups of pockmarks were identified: (1) a group of large (>10 m diameter), more widely scattered pockmarks deeply rooted (up to 8 ms two-way travel time, TWTT) in the Holocene palaeo-valley infills, and (2) a group of smaller, more densely spaced pockmarks shallowly rooted (up to 2 ms TWTT) in interfluve deposits. Pockmark pore water analyses revealed high methane concentrations peaking at ca. 400 μl/l at 22 and 30 cm core depth in silty sediments immediately above Haploops-bearing layers. Water column data indicate acoustic plumes above pockmarks, implying ongoing pockmark activity. Pockmark gas and/or fluid expulsion resulting in increased turbidity (resuspension of, amongst others, freshly settled phytoplankton) could at least partly account for the strong spatial association with the phytoplankton-feeding H. nirae in the Bay of Concarneau, exacerbating impacts of anthropogenically induced eutrophication and growing offshore trawling activities. Tidally driven hydraulic pumping in gas-charged pockmarks represents a good candidate as large-scale short-term triggering mechanism of pockmark activation, in addition to episodic regional seismic activity.

  7. DESIGN AND APPLICATION OF MAGNETIC BEARING SUSPENSION SYSTEM IN A THREE PHASE INDUCTION MOTOR

    Osman GÜRDAL; Yusuf ÖNER

    1998-01-01

    The current popularity of suspension and levitation stems no doubt the possibilities in high-speed ground transportation schemes. Although these are both challenging and exciting, there is considerable scope for application of suspension techniques to achieving frictionless bearing. The requirement in this case is often for close tolerances, low power consumption, small airgaps and ingeneral, compactness. Thus, magnetic suspension using DC electromagnets schemes have received more attention t...

  8. Electrostatic Suspension System Nonlinear Character Analysis and Its Internal Model Control

    2007-01-01

    Nonlinearity is an important characteristic in electrostatic suspension system (ESS). This paper concludes the nonlinear parts in ESS, which generally result from the relationships between rotor displacement and capacitance, rotor displacement and electrostatic force, and control voltage and electrostatic force. In terms of the nonlinearities, a new control method with modified internal model control (IMC) was proposed to analyze the ESS, deduce the transfer function of the modified IMC controller in ESS, and simulate this new application in ESS. Comparing with proportional integral derivative (PID)control, IMC has only a parameter, and has better performance. As a result, IMC solves nonlinearity error well in ESS with only one uncertain parameter, and performs well when the rotor has large displacement.

  9. Drag measurements on a modified prolate spheroid using a magnetic suspension and balance system

    Dress, David A.

    1989-01-01

    Low-speed wind tunnel drag force measurements were taken on a modified prolate spheroid free of support interference. This body was tested at zero incidence in the NASA Langley 13 inch Magnetic Suspension and Balance System. This shape was one of two bodies tested to determine the drag force measuring capabilities of the 13 inch MSBS. In addition, support interference on this shape at zero incidence was quantified by using a dummy sting. The drag force calibrations and wind-on repeatability data make it possible to assess the drag force measuring capabilities of the 13 inch MSBS. Comparisons with and without the sting showed differences in the drag coefficients with the dummy sting case resulting in lower drag coefficients.

  10. Further investigation into calibration techniques for a magnetic suspension and balance system

    Eskins, J.

    1986-01-01

    Calibrations performed on three different magnetic cores for wind tunnel models suspended in the Southampton University Magnetic Suspension and Balance System (SUMSBS) are detailed. The first core investigated was the Southampton University pilot Superconducting Solenoid model, first flown in July 1983. Static calibrations of lift force, drag force and pitching moment, together with lift force and pitching moment calibrations determined by the dynamic method are detailed in this report. Other types of core investigated in a similar manner were conventional permanent magnets, Alnico and samarium-cobalt. All static calibrations gave a linear dependence of force on electromagnet current as expected. Dynamic calibrations are faster to perform but are proving to be not as easily analyzed as static calibrations. There are still some effects to be explained but dynamic lift calibration results were obtained agreeing to within 2 percent of the static calibration value.