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Sample records for son john servos

  1. Disability in the Family: John and Alice Dewey Raising Their Son Sabino

    Science.gov (United States)

    Danforth, Scot

    2018-01-01

    Background/Context: The current biographic understanding of John Dewey's experience adopting and raising an Italian boy named Sabino emphasizes the theme of finding an emotional replacement for Morris and Gordon, two young sons who had tragically died on family trips to Europe. Lacking is substantive attention to the fact that John Dewey's son had…

  2. Visual servoing in medical robotics: a survey. Part II: tomographic imaging modalities--techniques and applications.

    Science.gov (United States)

    Azizian, Mahdi; Najmaei, Nima; Khoshnam, Mahta; Patel, Rajni

    2015-03-01

    Intraoperative application of tomographic imaging techniques provides a means of visual servoing for objects beneath the surface of organs. The focus of this survey is on therapeutic and diagnostic medical applications where tomographic imaging is used in visual servoing. To this end, a comprehensive search of the electronic databases was completed for the period 2000-2013. Existing techniques and products are categorized and studied, based on the imaging modality and their medical applications. This part complements Part I of the survey, which covers visual servoing techniques using endoscopic imaging and direct vision. The main challenges in using visual servoing based on tomographic images have been identified. 'Supervised automation of medical robotics' is found to be a major trend in this field and ultrasound is the most commonly used tomographic modality for visual servoing. Copyright © 2014 John Wiley & Sons, Ltd.

  3. ¿Son los hechos sociales una clase de hechos mentales? Una crítica materialista a la ontología social de John R. Searle

    Directory of Open Access Journals (Sweden)

    JOSÉ ANTONIO NOGUERA

    2002-01-01

    Full Text Available El presente artículo lleva a cabo un análisis crítico de algunos aspectos de la obra de John R. Searle, La construcción de la realidad social (1995. Partiendo del acuerdo con Searle sobre la necesidad de abandonar el llamado "construccionismo social", se valora hasta qué punto la argumentación del autor resulta exitosa en este empeño. A este respecto, se defienden las siguientes tesis: a La ontología social de Searle está parcialmente lastrada por un inadecuado mentalismo, esto es, por la reducción de todos los hechos sociales a hechos mentales o representaciones superpuestas o hechos "brutos". b El mentalismo de Searle no le aleja lo suficiente de los construccionistas sociales, sino que su desarrollo coherente acaba teniendo consecuencias construccionistas e idealistas a pesar suyo. c Para superar estas limitaciones se debería demostrar que hay hechos sociales que no son ni hechos brutos ni hechos mentales ni simples combinaciones de ambos; se sostendrá que un concepto analíticamente reconstruido de praxis puede ser un buen punto de partida para desarrollar esta estregia, que puede ser un paso en la construcción de una ontología social materialista.

  4. HYDRAULIC SERVO CONTROL MECHANISM

    Science.gov (United States)

    Hussey, R.B.; Gottsche, M.J. Jr.

    1963-09-17

    A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

  5. Visual servoing in medical robotics: a survey. Part I: endoscopic and direct vision imaging - techniques and applications.

    Science.gov (United States)

    Azizian, Mahdi; Khoshnam, Mahta; Najmaei, Nima; Patel, Rajni V

    2014-09-01

    Intra-operative imaging is widely used to provide visual feedback to a clinician when he/she performs a procedure. In visual servoing, surgical instruments and parts of tissue/body are tracked by processing the acquired images. This information is then used within a control loop to manoeuvre a robotic manipulator during a procedure. A comprehensive search of electronic databases was completed for the period 2000-2013 to provide a survey of the visual servoing applications in medical robotics. The focus is on medical applications where image-based tracking is used for closed-loop control of a robotic system. Detailed classification and comparative study of various contributions in visual servoing using endoscopic or direct visual images are presented and summarized in tables and diagrams. The main challenges in using visual servoing for medical robotic applications are identified and potential future directions are suggested. 'Supervised automation of medical robotics' is found to be a major trend in this field. Copyright © 2013 John Wiley & Sons, Ltd.

  6. Automated servo controlled calorimetry

    International Nuclear Information System (INIS)

    Wetzel, J.R.

    1984-01-01

    A method of operating a calorimeter is called the servo controlled method. An internal heater is driven by a controlled voltage source to produce a constant internal temperature. The heater power is controlled by a digital computer program that uses as one of its inputs the bridge potential. The heater power can be calculated by multiplying the heater current by the heater voltage. A bridge potential can then be determined that will produce the desired internal power level. When a sample is placed in the calorimeter the servo system reduces the heater power to maintain the set point bridge potential. There will be four calorimeters in the system - two for large sizes and two for small sizes. They will be servo controlled using a DEC Micro-11 computer with a IEEE-488 interface buss

  7. Ultrasound image based visual servoing for moving target ablation by high intensity focused ultrasound.

    Science.gov (United States)

    Seo, Joonho; Koizumi, Norihiro; Mitsuishi, Mamoru; Sugita, Naohiko

    2017-12-01

    Although high intensity focused ultrasound (HIFU) is a promising technology for tumor treatment, a moving abdominal target is still a challenge in current HIFU systems. In particular, respiratory-induced organ motion can reduce the treatment efficiency and negatively influence the treatment result. In this research, we present: (1) a methodology for integration of ultrasound (US) image based visual servoing in a HIFU system; and (2) the experimental results obtained using the developed system. In the visual servoing system, target motion is monitored by biplane US imaging and tracked in real time (40 Hz) by registration with a preoperative 3D model. The distance between the target and the current HIFU focal position is calculated in every US frame and a three-axis robot physically compensates for differences. Because simultaneous HIFU irradiation disturbs US target imaging, a sophisticated interlacing strategy was constructed. In the experiments, respiratory-induced organ motion was simulated in a water tank with a linear actuator and kidney-shaped phantom model. Motion compensation with HIFU irradiation was applied to the moving phantom model. Based on the experimental results, visual servoing exhibited a motion compensation accuracy of 1.7 mm (RMS) on average. Moreover, the integrated system could make a spherical HIFU-ablated lesion in the desired position of the respiratory-moving phantom model. We have demonstrated the feasibility of our US image based visual servoing technique in a HIFU system for moving target treatment. © 2016 The Authors The International Journal of Medical Robotics and Computer Assisted Surgery Published by John Wiley & Sons Ltd.

  8. Characteristic analysis of servo valve

    International Nuclear Information System (INIS)

    Ko, J. H.; Ryu, D. R.; Lee, J. H.; Kim, Y. S.; Na, J. C.; Kim, D. S.

    2008-01-01

    Electro-pneumatic servo valve is an electro-mechanical device which converts electric signals into a proper pneumatic flow rate or pressure. In order to improve the overall performance of pneumatic servo systems, electro-pneumatic servo valves are required, which have fast dynamic characteristics, no air leakage at a null point, and can be fabricated at a low-cost. The first objective of this research is to design and to fabricate a new electro-pneumatic servo valve which satisfies the above-mentioned requirements. In order to design the mechanism of the servo valve optimally, the flow inside the valve depending upon the position of spool was analyzed variously, and on the basis of such analysis results, the valve mechanism, which was formed by combination of the spool and the sleeve, was designed and manufactured. And a tester for conducting an overall performance test was designed and manufactured, and as a result of conducting the flow rate test, the pressure test and the frequency test on the developed pneumatic servo valve

  9. Dynamic Characteristics of DC Servo Motor Driven by Conventional Servo Driver: Estimation of Circuit Constants in Conventional Servo Driver

    OpenAIRE

    酒井, 史敏; 神谷, 好承; 関, 啓明; 疋津, 正利

    2000-01-01

    DC servo motors that are made as manufactured goods in the factory are widely used as actuators for driving many automatic machines. Then the manufactured driver (amplifier) that is matched to its servo motor is coveniently chosen to drive when aiming at high performance of the motion control. Motion of motor that is driven by the manufactured servo driver has very complicated dynamic characteristics. In this study, it is tried to make clear about inner composition of the servo driver through...

  10. Hydraulic servo control spool valve

    Science.gov (United States)

    Miller, Donald M.

    1983-01-01

    A servo operated spool valve having a fixed sleeve and axially movable spool. The sleeve is machined in two halves to form a long, narrow tapered orifice slot across which a transverse wall of the spool is positioned. The axial position of the spool wall along the slot regulates the open orifice area with extreme precision.

  11. Visual-servoing optical microscopy

    Science.gov (United States)

    Callahan, Daniel E.; Parvin, Bahram

    2009-06-09

    The present invention provides methods and devices for the knowledge-based discovery and optimization of differences between cell types. In particular, the present invention provides visual servoing optical microscopy, as well as analysis methods. The present invention provides means for the close monitoring of hundreds of individual, living cells over time: quantification of dynamic physiological responses in multiple channels; real-time digital image segmentation and analysis; intelligent, repetitive computer-applied cell stress and cell stimulation; and the ability to return to the same field of cells for long-term studies and observation. The present invention further provides means to optimize culture conditions for specific subpopulations of cells.

  12. Digitalni servo sistem za upravljanje infracrvenim lokatorom

    OpenAIRE

    Aleksandar Viličić; Mirko Jezdimirović

    2009-01-01

    U radu je predstavljen digitalni servo sistem sa pogonskim elektromotorom koji zamenjuje postojeći elektrohidraulički servo pogon na uređaju za upravljanje IC lokatorom, koji obezbeđuje zahtevanu tačnost pozicioniranja i praćenja sa minimalnim brzinama.

  13. John Stachel

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. John Stachel. Articles written in Resonance – Journal of Science Education. Volume 3 Issue 8 August 1998 pp 76-92 Reflections. Albert Einstein-The Man Behind the Myths · John Stachel · More Details Fulltext PDF ...

  14. Experimental research of flow servo-valve

    Directory of Open Access Journals (Sweden)

    Takosoglu Jakub

    2017-01-01

    Full Text Available Positional control of pneumatic drives is particularly important in pneumatic systems. Some methods of positioning pneumatic cylinders for changeover and tracking control are known. Choking method is the most development-oriented and has the greatest potential. An optimal and effective method, particularly when applied to pneumatic drives, has been searched for a long time. Sophisticated control systems with algorithms utilizing artificial intelligence methods are designed therefor. In order to design the control algorithm, knowledge about real parameters of servo-valves used in control systems of electro-pneumatic servo-drives is required. The paper presents the experimental research of flow servo-valve.

  15. Experimental research of flow servo-valve

    Science.gov (United States)

    Takosoglu, Jakub

    Positional control of pneumatic drives is particularly important in pneumatic systems. Some methods of positioning pneumatic cylinders for changeover and tracking control are known. Choking method is the most development-oriented and has the greatest potential. An optimal and effective method, particularly when applied to pneumatic drives, has been searched for a long time. Sophisticated control systems with algorithms utilizing artificial intelligence methods are designed therefor. In order to design the control algorithm, knowledge about real parameters of servo-valves used in control systems of electro-pneumatic servo-drives is required. The paper presents the experimental research of flow servo-valve.

  16. Recent results in visual servoing

    Science.gov (United States)

    Chaumette, François

    2008-06-01

    Visual servoing techniques consist in using the data provided by a vision sensor in order to control the motions of a dynamic system. Such systems are usually robot arms, mobile robots, aerial robots,… but can also be virtual robots for applications in computer animation, or even a virtual camera for applications in computer vision and augmented reality. A large variety of positioning tasks, or mobile target tracking, can be implemented by controlling from one to all the degrees of freedom of the system. Whatever the sensor configuration, which can vary from one on-board camera on the robot end-effector to several free-standing cameras, a set of visual features has to be selected at best from the image measurements available, allowing to control the degrees of freedom desired. A control law has also to be designed so that these visual features reach a desired value, defining a correct realization of the task. With a vision sensor providing 2D measurements, potential visual features are numerous, since as well 2D data (coordinates of feature points in the image, moments, …) as 3D data provided by a localization algorithm exploiting the extracted 2D measurements can be considered. It is also possible to combine 2D and 3D visual features to take the advantages of each approach while avoiding their respective drawbacks. From the selected visual features, the behavior of the system will have particular properties as for stability, robustness with respect to noise or to calibration errors, robot 3D trajectory, etc. The talk will present the main basic aspects of visual servoing, as well as technical advances obtained recently in the field inside the Lagadic group at INRIA/INRISA Rennes. Several application results will be also described.

  17. Study of Servo Press with a Flywheel

    Science.gov (United States)

    Tso, Pei-Lum; Li, Cheng-Ho

    The servo press with a flywheel is able to provide flexible motions with energy-saving merit, but its true potential has not been thoroughly studied and verified. In this paper, such the “hybrid-driven” servo press is focused on, and the stamping capacity and the energy distribution between the flywheel and the servomotor are investigated. The capacity is derived based on the principle of energy conservation, and a method of using a capacity percentage plane for evaluation is proposed. A case study is included to illustrate and interpret that the stamping capacity is highly dependent on the programmed punch motions, thus the capacity prediction is always necessary while applying this kind of servo press. The energy distribution is validated by blanking experiments, and the results indicate that the servomotor needs only to provide 15% to the flywheel torque, 12% of the total stamping energy. This validates that the servomotor power is significantly saved in comparison with conventional servo presses.

  18. Aerial Object Following Using Visual Fuzzy Servoing

    OpenAIRE

    Olivares Méndez, Miguel Ángel; Mondragon Bernal, Ivan Fernando; Campoy Cervera, Pascual; Mejias Alvarez, Luis; Martínez Luna, Carol Viviana

    2011-01-01

    This article presents a visual servoing system to follow a 3D moving object by a Micro Unmanned Aerial Vehicle (MUAV). The presented control strategy is based only on the visual information given by an adaptive tracking method based on the color information. A visual fuzzy system has been developed for servoing the camera situated on a rotary wing MAUV, that also considers its own dynamics. This system is focused on continuously following of an aerial moving target object, maintai...

  19. IUSThrust Vector Control (TVC) servo system

    Science.gov (United States)

    Conner, G. E.

    1979-01-01

    The IUS TVC SERVO SYSTEM which consists of four electrically redundant electromechanical actuators, four potentiometer assemblies, and two controllers to provide movable nozzle control on both IUS solid rocket motors is developed. An overview of the more severe IUS TVC servo system design requirements, the system and component designs, and test data acquired on a preliminary development unit is presented. Attention is focused on the unique methods of sensing movable nozzle position and providing for redundant position locks.

  20. Vision servo of industrial robot: A review

    Science.gov (United States)

    Zhang, Yujin

    2018-04-01

    Robot technology has been implemented to various areas of production and life. With the continuous development of robot applications, requirements of the robot are also getting higher and higher. In order to get better perception of the robots, vision sensors have been widely used in industrial robots. In this paper, application directions of industrial robots are reviewed. The development, classification and application of robot vision servo technology are discussed, and the development prospect of industrial robot vision servo technology is proposed.

  1. John Lindsay

    CERN Multimedia

    2005-01-01

    A few weeks ago John Lindsay passed away unexpectedly at his home in St. Genis. With his death we have lost a pioneer in detector electronics and one of the founding fathers of the CERN Electronics Group. John came to CERN in 1956 to join the Electronics Group, which was being formed in the SC Division. He thus participated from the beginning in the design, development, production, commissioning and support of electronics for the experiments at the CERN accelerators, initially at the SC and finally at the SPS. From the University of Glasgow he brought his expertise on pulse height analyzers, which were called kick sorters in those days, and did pioneering work with it in the early CERN experiments. He designed read-out systems for successive generations of detectors, such as wire spark chambers, multiwire proportional chambers, calorimeters, etc., often coming up with innovative solutions. Surely one of his finest moments must have been when he worked on complex detector systems, such as liquid argon calo...

  2. A low order adaptive control scheme for hydraulic servo systems

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Pedersen, Henrik Clemmensen; Bech, Michael Møller

    2015-01-01

    This paper deals with high-performance position control of hydraulics servo systems in general. The hydraulic servo system used is a two link robotic manipulator actuated by two hydraulic servo cylinders. A non-linear model of the hydraulic system and a Newton-Euler based model of the mechanical...

  3. Nonlinear friction model for servo press simulation

    Science.gov (United States)

    Ma, Ninshu; Sugitomo, Nobuhiko; Kyuno, Takunori; Tamura, Shintaro; Naka, Tetsuo

    2013-12-01

    The friction coefficient was measured under an idealized condition for a pulse servo motion. The measured friction coefficient and its changing with both sliding distance and a pulse motion showed that the friction resistance can be reduced due to the re-lubrication during unloading process of the pulse servo motion. Based on the measured friction coefficient and its changes with sliding distance and re-lubrication of oil, a nonlinear friction model was developed. Using the newly developed the nonlinear friction model, a deep draw simulation was performed and the formability was evaluated. The results were compared with experimental ones and the effectiveness was verified.

  4. Son, Sent, and Servant

    Directory of Open Access Journals (Sweden)

    Truls Åkerlund

    2015-11-01

    Full Text Available This study challenges the claim that Jesus is the archetypical servant leader as described in contempo-rary leadership literature. Based on a theological reading of the Fourth Gospel, the paper suggests that, as a servant, Jesus cannot be understood apart from his mission and obedience to God. Consequently, Jesus was not primarily a servant leader but rather the Son who was sent to the world to enact the Fa-ther’s will. In this regard, the Fourth Gospel provides a unique perspective that is barely noted in the current discourse on servant leadership modelled on the example of Christ. Although certain aspects of servant leadership theory correspond to John’s portrayal of Jesus, the study concludes that other de-scriptions of him as a servant leader suffer from a one-sided and reductionist Christology. Implications of this view for Christian ministry are briefly sketched out.

  5. Compact, Lightweight Servo-Controllable Brakes

    Science.gov (United States)

    Lovchik, Christopher S.; Townsend, William; Guertin, Jeffrey; Matsuoka, Yoky

    2010-01-01

    Compact, lightweight servo-controllable brakes capable of high torques are being developed for incorporation into robot joints. A brake of this type is based partly on the capstan effect of tension elements. In a brake of the type under development, a controllable intermediate state of torque is reached through on/off switching at a high frequency.

  6. Magnetic particle clutch controls servo system

    Science.gov (United States)

    Fow, P. B.

    1973-01-01

    Magnetic clutches provide alternative means of driving low-power rate or positioning servo systems. They may be used over wide variety of input speed ranges and weigh comparatively little. Power drain is good with overall motor/clutch efficiency greater than 50 percent, and gain of clutch is close to linear, following hysteresis curve of core and rotor material.

  7. Synthesis of Servo Pneumatic/Hydraulic Drive

    Directory of Open Access Journals (Sweden)

    K D. Efremova

    2017-01-01

    Full Text Available Servo pneumatic and / or hydraulic drives are widely used in modern engineering and process control. The efficiency of using pneumatic / hydraulic drives depends on their parameters and characteristics. To select the optimal drive parameters, various methods are used, based on finding the minimum of the target (target or criteria function.The objective of this paper was to apply one crucial criterion (target function that provides determination of optimal parameters of the pneumatic / hydraulic drive with the translational motion of the end-effector as well as its use in the synthesis of the servo pneumatic cylinder. The article shows the form of the target function representing a set of drive parameters that do not have direct relationships with each other in a dimensionless form for the pneumatic / hydraulic drive with the translational motion of the end-effector. To calculate the parameters of the servo drive close to the optimal ones, a two-criteria LPτ search was used. As criteria, were used the decisive criterion - the proposed target function, and the power developed by the actuator of the pneumatic / hydraulic drive, which were presented in a dimensionless form. It is shown that the criterion for solution optimality is the minimum distance of the selected point in the space of the normalized criteria from the origin. This point was determined. In addition to the proposed criteria, non-formalised requirements were taken into account: actual and mass-produced components of drive, in terms of which its parameters close to the optimal ones were determined, and the maximum relative error of the obtained useful power value of the servo pneumatic drive was estimated. The paper presents design features of two types of the servo pneumatic drive created, taking into account the proposed target function, implemented according to the schemes "hidden" and "spaced apart". The experimental static characteristic of the servo pneumatic drive is

  8. À chacun son puzzle

    Directory of Open Access Journals (Sweden)

    Jean-Noël Ferrié

    2012-05-01

    Full Text Available Le texte soutient que le « tournant naturaliste » que l’on nous invite à négocier ne donne aucun moyen supplémentaire pour parvenir à une description perspicace de ce que les gens font dans des circonstances précises, l’existence humaine pouvant être considérée comme une collection de circonstances précises. Sans doute le naturalisme nous permet-il de comprendre comment certaines actions humaines sont possibles, mais cela ne nous dit pas pourquoi et comment elles font sens pour tout un chacun. La méthodologie nécessaire pour éclaircir le premier point obscurcit généralement le second. Le mieux est donc de considérer que les deux approches ne vont pas de pair. Ce point de vue est soutenu à partir d’exemple tirés de l’anthropologie de la religion.To each one his puzzle. For a serene methodological pluralismThe text argues that the « naturalistic turn » that we are invited to negotiate does not give any additional means to achieve an insightful description of what people do in specific circumstances, and human existence can be considered as a collection of specific circumstances. Probably naturalism allows us to understand how some human actions are possible, but that does not tell us why and how they make sense for everyone. The methodology needed to clarify the first point usually obscures the second one. The best way is to consider that the two approaches do not go together. The text supports this view from an example drawn from the anthropology of religion.A cada uno su rompecabezas. En favor de un pluralismo metodológico serenoEl texto argumenta que la inflexión naturalista a la que se nos invita a participar no proporciona ningún medio suplementario que desemboque en una descripción perspicaz de lo que la gente hace en circunstancias concretas ya que la existencia humana puede ser considerada como una concatenación de circunstancias concretas. Sin duda el naturalismo nos permite comprender como son

  9. Cloud-based Networked Visual Servo Control

    OpenAIRE

    Wu, Haiyan; Lu, Lei; Chen, Chih-Chung; Hirche, Sandra; Kühnlenz, Kolja

    2013-01-01

    The performance of vision-based control systems, in particular of highly dynamic vision-based motion control systems, is often limited by the low sampling rate of the visual feedback caused by the long image processing time. In order to overcome this problem, the networked visual servo control, which integrates networked computational resources for cloud image processing, is considered in this article. The main contributions of this article are i) a real-time transport protocol for transmitti...

  10. Peter St. John | NREL

    Science.gov (United States)

    St. John Photo of Peter St. John Peter St. John Researcher III-Chemical Engineering Peter.StJohn @nrel.gov | 303-384-7969 Orcid ID http://orcid.org/0000-0002-7928-3722 Education Peter St. John received his engineering from the University of California at Santa Barbara in 2015. During his Ph.D., St. John applied

  11. Dual arm master controller for a bilateral servo-manipulator

    Science.gov (United States)

    Kuban, Daniel P.; Perkins, Gerald S.

    1989-01-01

    A master controller for a mechanically dissimilar bilateral slave servo-manipulator is disclosed. The master controller includes a plurality of drive trains comprising a plurality of sheave arrangements and cables for controlling upper and lower degrees of master movement. The cables and sheaves of the master controller are arranged to effect kinematic duplication of the slave servo-manipulator, despite mechanical differences therebetween. A method for kinematically matching a master controller to a slave servo-manipulator is also disclosed.

  12. Control system for the Fermilab Master-Slave servo manipulator

    International Nuclear Information System (INIS)

    Ducar, R.J.

    1977-01-01

    A control system for the Fermilab Master-Slave servo manipulator was developed. This new system offers a significant improvement in operational performance over the extant servo design with additional emphasis on simplicity of operation and maintainability. The servo manipulator is force-reflecting in each of the seven independent bilateral motions. Master force multiplication is automatically increased as the slave force is increased to its fifty pound capacity. The design incorporates triac control of the low inertia two-phase servomotors and makes extensive use of digital circuits in the servo loops. The manipulator is utilized in servicing radioactive beam-line targeting equipment

  13. Servo Reduces Friction In Flexure Bearing

    Science.gov (United States)

    Clingman, W. Dean

    1991-01-01

    Proposed servocontrol device reduces such resistive torques as stiction, friction, ripple, and cogging in flexure bearing described in LAR-14348, "Flexure Bearing Reduces Startup Friction". Reduces frictional "bump" torque encountered when bearing ball runs into buildup of grease on bearing race. Also used as cable follower to reduce torque caused by cable and hoses when they bend because of motion of bearing. New device includes torquer across ball race. Torquer controlled by servo striving to keep flexure at null, removing torque to outer ring. In effect, device is inner control loop reducing friction, but does not control platforms or any outer-control-loop functions.

  14. Stepping Motor - Hydraulic Motor Servo Drives for an NC Milling ...

    African Journals Online (AJOL)

    In this paper the retrofit design of the control system of an NC milling machine with a stepping motor and stepping motor - actuated hydraulic motor servo mechanism on the machines X-axis is described. The servo designed in the course of this study was tested practically and shown to be linear - the velocity following errors ...

  15. Experimental evaluation of control strategies for hydraulic servo robot

    DEFF Research Database (Denmark)

    Bech, Michael Møller; Andersen, Torben Ole; Pedersen, Henrik C.

    2013-01-01

    In this paper different linear and non-linear controllers applied to a hydraulically driven servo robot are evaluated and validated. The task is to make the actuators of the manipulator track a position reference with minimum error. Hydraulic systems are intrinsically non-linear and using linear...... in industrial servo drives. The different controllers are compared and evaluated from simulation and experimental results....

  16. Review on Sons and Lovers

    Institute of Scientific and Technical Information of China (English)

    顾燕君

    2013-01-01

    This essay centralizes on the analysis of the writing skills, the theme and my personal insights of Sons and Lovers, as well as my interpretation of the mother-son relationship in terms of feminism. Overall, hope it will provide a specific perspective of this renowned novel and arouse the readers’attention to interpret the novel themselves.

  17. Forming of AHSS using Servo-Presses

    Science.gov (United States)

    Groseclose, Adam Richard

    Stamping of Advanced High Strength Steel (AHSS) alloys poses several challenges due to the material's higher strength and low formability compared to conventional steels and other problems such as (a) inconsistency of incoming material properties, (b) ductile fracture during forming, (c) higher contact pressure and temperature rise during forming, (d) higher die wear leading to reduced tool life, (e) higher forming load/press capacity, and (f) large springback leading to dimensional inaccuracy in the formed part. [Palaniswamy et. al., 2007]. The use of AHSS has been increasing steadily in automotive stamping. New AHSS alloys (TRIP, TWIP) may replace some of the Hot Stamping applications. Stamping of AHSS alloys, especially higher strength materials, 780 MPa and higher, present new challenges in obtaining good part definition (corner and fillet radii), formability (fracture and resulting scrap) and in reducing springback. Servo-drive presses, having the capability to have infinitely variable and adjustable ram speed and dwell at BDC, offer a potential improvement in quality, part definition, and springback reduction especially when the infinitely adjustable slide motion is used in combination with a CNC hydraulic cushion. Thus, it is desirable to establish a scientific/engineering basis for improving the stamping conditions in forming AHSS using a servo-drive press.

  18. Fuzzy control of small servo motors

    Science.gov (United States)

    Maor, Ron; Jani, Yashvant

    1993-01-01

    To explore the benefits of fuzzy logic and understand the differences between the classical control methods and fuzzy control methods, the Togai InfraLogic applications engineering staff developed and implemented a motor control system for small servo motors. The motor assembly for testing the fuzzy and conventional controllers consist of servo motor RA13M and an encoder with a range of 4096 counts. An interface card was designed and fabricated to interface the motor assembly and encoder to an IBM PC. The fuzzy logic based motor controller was developed using the TILShell and Fuzzy C Development System on an IBM PC. A Proportional-Derivative (PD) type conventional controller was also developed and implemented in the IBM PC to compare the performance with the fuzzy controller. Test cases were defined to include step inputs of 90 and 180 degrees rotation, sine and square wave profiles in 5 to 20 hertz frequency range, as well as ramp inputs. In this paper we describe our approach to develop a fuzzy as well as PH controller, provide details of hardware set-up and test cases, and discuss the performance results. In comparison, the fuzzy logic based controller handles the non-linearities of the motor assembly very well and provides excellent control over a broad range of parameters. Fuzzy technology, as indicated by our results, possesses inherent adaptive features.

  19. a speech act analysis of John 9: 35

    African Journals Online (AJOL)

    The significance of Jesus' utterance in relation to the Johannine son of man: a speech act analysis of John 9: 35: research. ... In order to accomplish that, this article will examine the significance of Jesus' utterance in John 9: 35, which contains some difficulty in interpreting the meaning of the title Son of Man.

  20. Dual arm master controller for a bilateral servo-manipulator

    International Nuclear Information System (INIS)

    Kuban, D.P.; Perkins, G.S.

    1989-01-01

    A master controller for a mechanically dissimilar bilateral slave servo-manipulator is disclosed. The master controller includes a plurality of drive trains comprising a plurality of sheave arrangements and cables for controlling upper and lower degrees of master movement. The cables and sheaves of the master controller are arranged to effect kinematic duplication of the slave servo-manipulator, despite mechanical differences there between. A method for kinematically matching a master controller to a slave servo-manipulator is also disclosed. 13 figs

  1. Designing compensator of dual servo system for high precision positioning

    International Nuclear Information System (INIS)

    Choi, Hyeun Seok; Song, Chi Woo; Han, Chang Soo; Choi, Tae Hoon; Lee, Nak Kyu; Na, Kyung Hwan

    2003-01-01

    The high precision positioning mechanism is used in various industrial fields. It is used in semiconductor manufacturing line, test instrument, bioengineering, and MEMS and so on. This paper presents a positioning mechanism with dual servo system. Dual servo system consists of a coarse stage and a fine motion stage. The course stage is driven by VCM and the actuator of fine stage is the PZT. The purposes of dual servo system are stability, higher bandwidth, and robustness. Lead compensator is applied to this control system, and is designed by PQ method. Designed compensator can improve property of positioning mechanism

  2. Motion control of servo cylinder using neural network

    International Nuclear Information System (INIS)

    Hwang, Un Kyoo; Cho, Seung Ho

    2004-01-01

    In this paper, a neural network controller that can be implemented in parallel with a PD controller is suggested for motion control of a hydraulic servo cylinder. By applying a self-excited oscillation method, the system design parameters of open loop transfer function of servo cylinder system are identified. Based on system design parameters, the PD gains are determined for the desired closed loop characteristics. The neural network is incorporated with PD control in order to compensate the inherent nonlinearities of hydraulic servo system. As an application example, a motion control using PD-NN has been performed and proved its superior performance by comparing with that of a PD control

  3. St. John's Wort (image)

    Science.gov (United States)

    The herb St. John's Wort is believed to be helpful in relieving mild to moderate depression, but should only be taken under a physician's supervision. St. John's Wort may clash with other medications or ...

  4. Direct drive digital servo press with high parallel control

    Science.gov (United States)

    Murata, Chikara; Yabe, Jun; Endou, Junichi; Hasegawa, Kiyoshi

    2013-12-01

    Direct drive digital servo press has been developed as the university-industry joint research and development since 1998. On the basis of this result, 4-axes direct drive digital servo press has been developed and in the market on April of 2002. This servo press is composed of 1 slide supported by 4 ball screws and each axis has linearscale measuring the position of each axis with high accuracy less than μm order level. Each axis is controlled independently by servo motor and feedback system. This system can keep high level parallelism and high accuracy even with high eccentric load. Furthermore the 'full stroke full power' is obtained by using ball screws. Using these features, new various types of press forming and stamping have been obtained by development and production. The new stamping and forming methods are introduced and 'manufacturing' need strategy of press forming with high added value and also the future direction of press forming are also introduced.

  5. The design of a servo system for a Moessbauer spectrometer

    International Nuclear Information System (INIS)

    Cranshaw, T.E.

    1981-06-01

    This report describes the design of a transducer system and servo drive amplifier suitable for Moessbauer spectrometers. Particular attention is paid to low and zero frequency drift. Measurements of the loop gain of a practical system are presented. (author)

  6. Servo Platform Circuit Design of Pendulous Gyroscope Based on DSP

    Science.gov (United States)

    Tan, Lilong; Wang, Pengcheng; Zhong, Qiyuan; Zhang, Cui; Liu, Yunfei

    2018-03-01

    In order to solve the problem when a certain type of pendulous gyroscope in the initial installation deviation more than 40 degrees, that the servo platform can not be up to the speed of the gyroscope in the rough north seeking phase. This paper takes the digital signal processor TMS320F28027 as the core, uses incremental digital PID algorithm, carries out the circuit design of the servo platform. Firstly, the hardware circuit is divided into three parts: DSP minimum system, motor driving circuit and signal processing circuit, then the mathematical model of incremental digital PID algorithm is established, based on the model, writes the PID control program in CCS3.3, finally, the servo motor tracking control experiment is carried out, it shows that the design can significantly improve the tracking ability of the servo platform, and the design has good engineering practice.

  7. Characteristic analysis and experiment of pneumatic servo valve

    International Nuclear Information System (INIS)

    Kim, Dong Soo; Lee, Won Hee; Choi, Byung Oh

    2004-01-01

    Electro-pneumatic servo valve is an electro-mechanical device which converts electric signals into a proper pneumatic flow rate or pressure. In order to improve the overall performance of pneumatic servo systems, electro-pneumatic servo valves are required, which have fast dynamic characteristics, no air leakage at a null point, and can be fabricated at a low-cost. The first objective of this research is to design and to fabricate a new electro-pneumatic servo valve which satisfies the above-mentioned requirements. In order to design the mechanism of the servo valve optimally, the flow inside the valve depending upon the position of spool was analyzed variously, and on the basis of such analysis results, the valve mechanism, which was formed by combination of the spool and the sleeve, was designed and manufactured. And a tester for conducting an overall performance test was designed and manufactured, and as a result of conducting the flow rate test, the pressure test and the frequency test on the developed pneumatic servo valve

  8. Development of friction welding method by electric servo motors; Dendo servo shiki masatsu assetsuho no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, H; Onuma, M; Hasegawa, T; Sakamoto, T [Toyota Motor Corp., Aichi (Japan)

    1997-10-01

    The standard friction welding has two methods; the brake method and the inertia method. We have developed a new friction welding method with the electric servo motor system. The forming of plastic fluidity layers of interface is evaluated quantitatively with the feedback control characteristics. The new method has enabled to reduce the heat effect and the burr of friction welding. In the method, we could reduce the getting heat energy, from one-third to half less than the previous methods. 6 refs., 16 figs.

  9. SAMSIN: the next-generation servo-manipulator

    International Nuclear Information System (INIS)

    Adams, R.H.; Jennrich, C.E.; Korpi, K.W.

    1985-01-01

    The Central Research Laboratories (CRL) Division of Sargent Industries is now developing SAMSIN, a next-generation servo-manipulator. SAMSIN is an acronym for Servo-Actuated Manipulator Systems with Intelligent Networks. This paper discusses the objectives of this development and describes the key features of the servo-manipulator system. There are three main objectives in the SAMSIN development: adaptability, reliability, and maintainability. SAMSIN utilizes standard Sargent/CRL sealed master and slave manipulator arms as well as newly developed compact versions. The mechanical arms have more than 20 yr of successful performance in industrial applications such as hot cells, high vacuums, fuel pools, and explosives handling. The servo-actuator package is in a protective enclosure, which may be sealed in various ways from the remote environment. The force limiting characteristics of the servo-actuators extend motion tendon life. Protective bootings increase the reliability of the arms in an environment that is high in airborne contamination. These bootings also simplify the decontamination of the system. The modularity in construction permits quick removal and replacement of slave arms, wrist joints, tong fingers, and actuator packages for maintenance. SAMSIN utilizes readily available off-the-shelf actuator and control system components. Each manipulator motion uses the same actuator and control system components

  10. John Dewey, an Appreciation

    Science.gov (United States)

    Clopton, Robert W.

    2015-01-01

    The subject of the annual Presidential address of Phi Kappa Phi, presented on May 8, 1962, was John Dewey. Dewey is identified in the public mind chiefly as an educational philosopher. In this address, the author describes the life and work of John Dewey as an indefatigable student of life whose interests ranged, like those of Aristotle, over the…

  11. John P Craig

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. John P Craig. Articles written in Resonance – Journal of Science Education. Volume 17 Issue 10 October 2012 pp 924-925 Article-in-a-Box. S N De - An Appreciation · John P Craig · More Details Fulltext PDF ...

  12. A John Wilson

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. A John Wilson. Articles written in Resonance – Journal of Science Education. Volume 11 Issue 7 July 2006 pp 70-76 Classroom. Inverting Matrices Constructed from Roots of Unity · A John Wilson · More Details Fulltext PDF ...

  13. Electromagnetic servoing-a new tracking paradigm.

    Science.gov (United States)

    Reichl, Tobias; Gardiazabal, José; Navab, Nassir

    2013-08-01

    Electromagnetic (EM) tracking is highly relevant for many computer assisted interventions. This is in particular due to the fact that the scientific community has not yet developed a general solution for tracking of flexible instruments within the human body. Electromagnetic tracking solutions are highly attractive for minimally invasive procedures, since they do not require line of sight. However, a major problem with EM tracking solutions is that they do not provide uniform accuracy throughout the tracking volume and the desired, highest accuracy is often only achieved close to the center of tracking volume. In this paper, we present a solution to the tracking problem, by mounting an EM field generator onto a robot arm. Proposing a new tracking paradigm, we take advantage of the electromagnetic tracking to detect the sensor within a specific sub-volume, with known and optimal accuracy. We then use the more accurate and robust robot positioning for obtaining uniform accuracy throughout the tracking volume. Such an EM servoing methodology guarantees optimal and uniform accuracy, by allowing us to always keep the tracked sensor close to the center of the tracking volume. In this paper, both dynamic accuracy and accuracy distribution within the tracking volume are evaluated using optical tracking as ground truth. In repeated evaluations, the proposed method was able to reduce the overall error from 6.64±7.86 mm to a significantly improved accuracy of 3.83±6.43 mm. In addition, the combined system provides a larger tracking volume, which is only limited by the reach of the robot and not the much smaller tracking volume defined by the magnetic field generator.

  14. Imaged-Based Visual Servo Control for a VTOL Aircraft

    Directory of Open Access Journals (Sweden)

    Liying Zou

    2017-01-01

    Full Text Available This paper presents a novel control strategy to force a vertical take-off and landing (VTOL aircraft to accomplish the pinpoint landing task. The control development is based on the image-based visual servoing method and the back-stepping technique; its design differs from the existing methods because the controller maps the image errors onto the actuator space via a visual model which does not contain the depth information of the feature point. The novelty of the proposed method is to extend the image-based visual servoing technique to the VTOL aircraft control. In addition, the Lyapunov theory is used to prove the asymptotic stability of the VTOL aircraft visual servoing system, while the image error can converge to zero. Furthermore, simulations have been also conducted to demonstrate the performances of the proposed method.

  15. Travailler loin de son domicile

    OpenAIRE

    Bonnet, Estelle; Verley, Elise; Ries, Tammy

    2017-01-01

    Résumé : La mobilité géographique liée à un lieu de travail éloigné du domicile – supposant soit de longs trajets quotidiens, soit de dormir en dehors du domicile – s’inscrit à l’articulation de la sphère professionnelle et de la sphère privée. Elle met à l’épreuve le couple et la distribution des rôles sexués en son sein. Cet article interroge les divisions sexuées inhérentes à cette articulation selon que l’on se place du point de vue d’une mobilité féminine ou masculine. Il examine en quoi...

  16. Optimum back-pressure forging using servo die cushion

    OpenAIRE

    Kawamoto, Kiichiro; Yoneyama, Takeshi; Okada, Masato; Kitayama, Satoshi; Chikahisa, Junpei

    2014-01-01

    This study focused on utilizing a servo die cushion (in conjunction with a servo press) as a "back-pressure load generator," to determine its effect on shape accuracy of the formed part and total forming load in forward extrusion during cold forging. The effect of back-pressure load application was confirmed in experiments, and the optimum setting pattern of back-pressure load was considered to minimize both shape accuracy of the formed part and back-pressure energy, which was representative ...

  17. Demythologizing John Dewey

    Science.gov (United States)

    Bhattacharya, N. C.

    1974-01-01

    This article takes a brief but critical look at John Dewey's version of pragmatism, his contribution to philosophical scholarship generally as well as his theory and practice of liberalism. (Author/RK)

  18. Sassis tuumamajandus / John Carey

    Index Scriptorium Estoniae

    Carey, John

    2008-01-01

    USA presidendikandidaadi John McCaini energeetikakava kohaselt tuleks USA-sse ehitada 100 uut tuumaelektrijaama, neist esimesed 45 peaksid valmima aastaks 2030. Tuumaelektrijaamad aitaksid rahuldada USA energiavajadust ning võitleksid ka kliimasoojenemise vastu. Eksperdid on arengukava suhtes kriitilised

  19. Interview with John Milnor

    DEFF Research Database (Denmark)

    Raussen, Martin; Skau, Christian

    2012-01-01

    This interview was given by Professor John Milnor in connection to the Abel Prize 2011 ceremony. Originally the interview appeared in the September issue of the Newsletter of the European Mathematical Society......This interview was given by Professor John Milnor in connection to the Abel Prize 2011 ceremony. Originally the interview appeared in the September issue of the Newsletter of the European Mathematical Society...

  20. Son huasteco e identidad regional

    Directory of Open Access Journals (Sweden)

    Rosa María Bonilla Burgos

    2013-04-01

    Full Text Available La población de la región Huasteca es partícipe de manifestaciones musicales en diferentes ámbitos, lo cual permite reconocer que entre todos los géneros utilizados destaca el son huasteco y su correspondiente bailable llamado huapango. Dichas expresiones musicales se impregnan de los ambientes tanto físico como social que viven constantemente. Es a través de las letras de los sones huastecos que se desarrolla el mecanismo para reflejar el mundo natural que perciben, y los acontecimientos que les suceden, cobrando una importancia que deriva en una identificación que trasciende. Conciben su entorno y lo refieren con sentido de pertenencia-apropiación, que les permite recrear su vida y fundirse en una identificación cultural a la que se le llamará “identidad regional”. La relevancia de considerar una expresión musical de estas características radica en que se preserva y enriquece constantemente unificando un área de México que no necesariamente corresponde a límites políticos establecidos en las diferentes etapas históricas.

  1. ...And Kronos Ate His Sons

    Science.gov (United States)

    Vitiello, Giuseppe

    In closed systems, energy is conserved. The origin of the time axis is completely arbitrary due to the invariance under continuous time-translations. The flowing of time swallows those fictitious origins one might assign on its axis, as Kronos ate his sons. Dissipation breaks such a scenario. It implies a non-forgettable origin of time. Open systems need their complement (their "double") in order to become, together, a closed system. Time emerges as an observable measured by the evolution of the open system complement, which acts as a clock. The conservation of the energy-momentum tensor in electrodynamics is considered and its relation with dissipative systems and self-similar fractal structures is discussed. The isomorphism with coherent states in quantum field theory (QFT) is established and the generator of transitions among unitarily inequivalent representations of the canonical commutation relations (CCR) is shown to provide sequences in time of phases, which defines the arrow of time. Merging properties of electrodynamics, fractal self-similarity, dissipation and coherent states point to an integrated vision of Nature.

  2. Stability and servo-control of the crystal pulling process

    International Nuclear Information System (INIS)

    Johansen, T.H.

    1990-11-01

    The paper analyzes why the crystal pulling process needs servo-control, and how it can be implemented. Special emphasis is put on the fundamental question of inherent stability, and how to interpret the signal from a balance when the weighing method is used for cystal diameter detection. 15 refs., 13 figs

  3. Actuation and Control of a Micro Electrohydraulic Digital Servo Valve

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Z Q; Hu, M J; Pei, X; Ruan, J [MOE Key Laboratory of Mechanical Manufacture and Automation Zhejiang University of Technology, 310014 (China)

    2006-10-15

    Structure of the micro digital servo valve is given. A micro stepper motor is used as electrical-to-mechanical interface of the valve. A special mechanical device is designed to convert the rotation of the stepper motor into the linear motion of the spool. This moving conversion device functions through an eccentric ball head rigidly connected to the axis of the stepper motor and plugged into a slot at the central spool land. While the stepper motor rotates, the eccentric ball head will actuate the spool to make a linear motion. Unlike conventional servo or proportional valves, in which the spool is forced to central position by a spring force, when the current supply is switched off, the digital valve has a program to control the spool to its central position each time the electrical power supply is switched on or off. The two end screws are used to adjust the position of the sleeve to sustain a mechanical central position coincided with electrical central position given by the stepper motor after initialization. The adjustment has to be carried once before the first time the servo valve is put into service. This paper presents theoretical analysis and experimental study of dynamic characteristics of the proposed micro digital servo valve. Experimental results demonstrated that the valve takes the advantage of high accuracy and fast response.

  4. Visual servo control for a human-following robot

    CSIR Research Space (South Africa)

    Burke, Michael G

    2011-03-01

    Full Text Available This thesis presents work completed on the design of control and vision components for use in a monocular vision-based human-following robot. The use of vision in a controller feedback loop is referred to as vision-based or visual servo control...

  5. Actuation and Control of a Micro Electrohydraulic Digital Servo Valve

    International Nuclear Information System (INIS)

    Yu, Z Q; Hu, M J; Pei, X; Ruan, J

    2006-01-01

    Structure of the micro digital servo valve is given. A micro stepper motor is used as electrical-to-mechanical interface of the valve. A special mechanical device is designed to convert the rotation of the stepper motor into the linear motion of the spool. This moving conversion device functions through an eccentric ball head rigidly connected to the axis of the stepper motor and plugged into a slot at the central spool land. While the stepper motor rotates, the eccentric ball head will actuate the spool to make a linear motion. Unlike conventional servo or proportional valves, in which the spool is forced to central position by a spring force, when the current supply is switched off, the digital valve has a program to control the spool to its central position each time the electrical power supply is switched on or off. The two end screws are used to adjust the position of the sleeve to sustain a mechanical central position coincided with electrical central position given by the stepper motor after initialization. The adjustment has to be carried once before the first time the servo valve is put into service. This paper presents theoretical analysis and experimental study of dynamic characteristics of the proposed micro digital servo valve. Experimental results demonstrated that the valve takes the advantage of high accuracy and fast response

  6. Electrical servo actuator bracket. [fuel control valves on jet engines

    Science.gov (United States)

    Sawyer, R. V. (Inventor)

    1981-01-01

    An electrical servo actuator is mounted on a support arm which is allowed to pivot on a bolt through a fixed mounting bracket. The actuator is pivotally connected to the end of the support arm by a bolt which has an extension allowed to pass through a slot in the fixed mounting bracket. An actuator rod extends from the servo actuator to a crank arm which turns a control shaft. A short linear thrust of the rod pivots the crank arm through about 90 for full-on control with the rod contracted into the servo actuator, and full-off control when the rod is extended from the actuator. A spring moves the servo actuator and actuator rod toward the control crank arm once the actuator rod is fully extended in the full-off position. This assures the turning of the control shaft to a full-off position. A stop bolt and slot are provided to limit pivot motion. Once fully extended, the spring pivots the motion.

  7. MA-23-6000: underwater bilateral servo master slave manipulator

    International Nuclear Information System (INIS)

    Vertut, Jean

    The different types of manipulators, recent data on their dexterity and the underwater work possible with servo master slave manipulators are reviewed. The general specifications of the manipulator MA 23-6000 designed for the machine ERIC II are given [fr

  8. Photoelectric radar servo control system based on ARM+FPGA

    Science.gov (United States)

    Wu, Kaixuan; Zhang, Yue; Li, Yeqiu; Dai, Qin; Yao, Jun

    2016-01-01

    In order to get smaller, faster, and more responsive requirements of the photoelectric radar servo control system. We propose a set of core ARM + FPGA architecture servo controller. Parallel processing capability of FPGA to be used for the encoder feedback data, PWM carrier modulation, A, B code decoding processing and so on; Utilizing the advantage of imaging design in ARM Embedded systems achieves high-speed implementation of the PID algorithm. After the actual experiment, the closed-loop speed of response of the system cycles up to 2000 times/s, in the case of excellent precision turntable shaft, using a PID algorithm to achieve the servo position control with the accuracy of + -1 encoder input code. Firstly, This article carry on in-depth study of the embedded servo control system hardware to determine the ARM and FPGA chip as the main chip with systems based on a pre-measured target required to achieve performance requirements, this article based on ARM chip used Samsung S3C2440 chip of ARM7 architecture , the FPGA chip is chosen xilinx's XC3S400 . ARM and FPGA communicate by using SPI bus, the advantage of using SPI bus is saving a lot of pins for easy system upgrades required thereafter. The system gets the speed datas through the photoelectric-encoder that transports the datas to the FPGA, Then the system transmits the datas through the FPGA to ARM, transforms speed datas into the corresponding position and velocity data in a timely manner, prepares the corresponding PWM wave to control motor rotation by making comparison between the position data and the velocity data setted in advance . According to the system requirements to draw the schematics of the photoelectric radar servo control system and PCB board to produce specially. Secondly, using PID algorithm to control the servo system, the datas of speed obtained from photoelectric-encoder is calculated position data and speed data via high-speed digital PID algorithm and coordinate models. Finally, a

  9. Commemorating John Dyson

    Science.gov (United States)

    Pittard, Julian M.

    2015-03-01

    John Dyson was born on the 7th January 1941 in Meltham Mills, West Yorkshire, England, and later grew up in Harrogate and Leeds. The proudest moment of John's early life was meeting Freddie Trueman, who became one of the greatest fast bowlers of English cricket. John used a state scholarship to study at Kings College London, after hearing a radio lecture by D. M. McKay. He received a first class BSc Special Honours Degree in Physics in 1962, and began a Ph.D. at the University of Manchester Department of Astronomy after being attracted to astronomy by an article of Zdenek Kopal in the semi-popular journal New Scientist. John soon started work with Franz Kahn, and studied the possibility that the broad emission lines seen from the Orion Nebula were due to flows driven by the photoevaporation of neutral globules embedded in a HII region. John's thesis was entitled ``The Age and Dynamics of the Orion Nebula`` and he passed his oral examination on 28th February 1966.

  10. A parameter estimation for DC servo motor by using optimization process

    International Nuclear Information System (INIS)

    Arjoni Amir

    2010-01-01

    Modeling and simulation parameters of DC servo motor using Matlab Simulink software have been done. The objective to define the DC servo motor parameter estimation is to get DC servo motor parameter values (B, La, Ra, Km, J) which are significant value that can be used for actuation process of control systems. In the analysis of control systems DC the servo motor expressed by transfer function equation to make faster to be analyzed as a component of the actuator. To obtain the data model parameters and initial conditions of the DC servo motors is then carried out the processor modeling and simulation in which the DC servo motor combined with other components. To obtain preliminary data of the DC servo motor parameters as estimated venue, it is obtained from the data factory of the DC servo motor. The initial data parameters of the DC servo motor are applied for the optimization process by using nonlinear least square algorithm and minimize the cost function value so that the DC servo motors parameter values are obtained significantly. The result of the optimization process of the DC servo motor parameter values are B = 0.039881, J= 1.2608e-007, Km = 0.069648, La = 2.3242e-006 and Ra = 1.8837. (author)

  11. Precision position control of servo systems using adaptive back-stepping and recurrent fuzzy neural networks

    International Nuclear Information System (INIS)

    Kim, Han Me; Kim, Jong Shik; Han, Seong Ik

    2009-01-01

    To improve position tracking performance of servo systems, a position tracking control using adaptive back-stepping control(ABSC) scheme and recurrent fuzzy neural networks(RFNN) is proposed. An adaptive rule of the ABSC based on system dynamics and dynamic friction model is also suggested to compensate nonlinear dynamic friction characteristics. However, it is difficult to reduce the position tracking error of servo systems by using only the ABSC scheme because of the system uncertainties which cannot be exactly identified during the modeling of servo systems. Therefore, in order to overcome system uncertainties and then to improve position tracking performance of servo systems, the RFNN technique is additionally applied to the servo system. The feasibility of the proposed control scheme for a servo system is validated through experiments. Experimental results show that the servo system with ABS controller based on the dual friction observer and RFNN including the reconstruction error estimator can achieve desired tracking performance and robustness

  12. John Deakin: Double Exposures

    Directory of Open Access Journals (Sweden)

    Paul Rousseau

    2015-11-01

    Full Text Available In this series of short films made by Jonathan Law, the art historian James Boaden, and the curator of The John Deakin Archive, Paul Rousseau, discuss the double-exposure images made by the photographer John Deakin (1912-1972 in the 1950s and 1960s. The films ask you, firstly, to look closely at the images being discussed. Each one begins with a sustained and intense shot of a single image before opening up to a wide-ranging discussion about Deakin, double exposures, and photography.

  13. John Donne no Brasil

    Directory of Open Access Journals (Sweden)

    Jose Garcez Ghirardi

    2008-04-01

    Full Text Available O leitor fica sem saber a troco do que John Donne lhe surge de repente, num virar de página, e através de períodos que parecem responder a uma pergunta que não foi formulada.(... Ninguém, nem o Sr. Afrânio Coutinho falara, até então, de John Donne,(.... Simplesmente, esse trecho, como inúmeros outros (quase todos do livro, revela que leituras apaixonantes obrigaram o professor Afrânio Coutinho a tomar em seu caderno alguns apontamentos eruditos. (MARTINS 1983 vol.I:621

  14. Meharry-Johns Hopkins Center for Prostate Cancer Research

    Science.gov (United States)

    2015-11-01

    formerly at the Institute for Health, Social, and Community Research (IHSCR) Center for Survey Research ( CSR ) at Shaw University in Raleigh, NC...survey will be conducted at CSR which is now located at Johns Hopkins Bloomberg School of Public Health (JHBSPH) located in Raleigh, NC. The Sons...the strategy to contact sons for whom she had no address or phone number. It was hoped that the father will notify the son to contact the study

  15. John Cale avaldas memuaarid

    Index Scriptorium Estoniae

    1999-01-01

    Rockbändi "The Velvet Underground" asutajaliige John Cale avaldas oma autobiograafia "What's Welsh for Zen?". Koos biograafiakirjanik Victor Bockrisiga kirjutatud teos räägib 60ndate lõpu kultuurielust New Yorgis, koostööst Andy Warholiga jm.

  16. John Hennessey, Barrier Breaker

    Science.gov (United States)

    Nelson, Stephen J.

    2018-01-01

    John Hennessey lived a remarkable, full life as a professor, as a leader in his field of management and business, and moral, ethical leadership, and as dean at Dartmouth College's Tuck School of Business and provost at the University of Vermont. He was extraordinary on many fronts, a great man who lived in tumultuous times marked by world war as a…

  17. John Archibald Wheeler

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 1. John Archibald Wheeler - Man with Picturesque Imagination. Jayant V Narlikar. General Article Volume 18 Issue 1 January 2013 pp 22-28. Fulltext. Click here to view fulltext PDF. Permanent link:

  18. John Maynard Smith

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 11. John Maynard Smith (1920-2004). Featured Scientist Volume 10 Issue 11 November 2005 pp 110-110. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/010/11/0110-0110. Resonance ...

  19. John Donne no Brasil

    Directory of Open Access Journals (Sweden)

    Jose Garcez Ghirardi

    2003-04-01

    Full Text Available http://dx.doi.org/10.5007/2175-8026.2003n45p77 O leitor fica sem saber a troco do que John Donne lhe surge de repente, num virar de página, e através de períodos que parecem responder a uma pergunta que não foi formulada.(... Ninguém, nem o Sr. Afrânio Coutinho falara, até então, de John Donne,(.... Simplesmente, esse trecho, como inúmeros outros (quase todos do livro, revela que leituras apaixonantes obrigaram o professor Afrânio Coutinho a tomar em seu caderno alguns apontamentos eruditos. (MARTINS 1983 vol.I:621

  20. Oliver St John Gogarty.

    Science.gov (United States)

    Clarke, R W

    1997-01-01

    Oliver St John Gogarty--Otolaryngologist to fashionable Edwardian Dublin--was a distinguished poet and a Senator in the fledgling Irish Free State after its establishment in 1922. He numbered amongst his acquaintances the poet William Butler Yeats, the novelist James Joyce and a host of political and literary persona who helped to shape modern Ireland. He was satirised as 'stately plump Buck Mulligan' in Joyce's novel Ulysses.

  1. John Kenneth Hulm

    International Nuclear Information System (INIS)

    Hulm, J.

    1988-01-01

    John Hulm has made profound contributions to the field of superconductivity as a research scientist and as an engineer. He and his colleagues discovered the superconducting materials in commercial use today, and he played a key role in the development of commercial superconducting magnets. Dr. Hulm now serves as Chief Scientist at Westinghouse Electric Corporation. This story describes many milestones in the history of superconductivity and offers personal insight into this distinguished scientist

  2. Sir John Meurig Thomas.

    Science.gov (United States)

    Thomas, John Meurig

    2013-10-11

    "My greatest achievement has been to combine being a teacher, a researcher, and a popularizer of science for over 50 years. My worst nightmare is to find myself dumbstruck when I am about to give a lecture …︁" This and more about Sir John Meurig Thomas can be found on page 10938. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  4. Book in three volumes of dr. John Puricha: Theology and pedagogy of St. John Chrysostom

    Directory of Open Access Journals (Sweden)

    Parlić-Božović Jasna Lj.

    2011-01-01

    Full Text Available Before the is latest work of Bishop Dr John Puric, by its importance, analytically decorated works, an impressive and voluminous number of facts happy including pedagogical Serbian public. Specifically, our pedagogical public is missing in this way displayed the Orthodox point of view of observation pedagogical crown and top categories. Episkom John was the there / volume work attempted to provide the interested reader the personality profile of any precise data from the conception of St. John Crisostom by looking at the same time as its pedagogy, and theology. Moreover these two concepts and bringing them to their assence, John episcope them actually connects into one inseparable unity. Therefore, this work has a multiple value and importance esportance especially for educators, who have not tried or had the oppotunality to see and understand the pedagogy of Orthodox theology in general, decorated with the ideas of Saint John Chrysostom special. Mindfullpeace as heir and successor creative Cappadocia 'novonikejske' trijadologije, St. John Chrystom recognizes the statut of Divine pedagogy educational philanthropy and philanthropic saving of pedagogy in each of the three Divine Persons. God the Father is this part, written by Bishop John, and from the perspective of John Chrysostom, is uncreated and unborn educationak philanthropy source of grace of the Holy Trinity. God the Son, and of the Father, uncreated etrinilly born, only begotten Son of God, newborn Logos, Jesus Christ the God/ man, BewAdam is alive and saving, hypostatic Ikonomija God, great mystery of the faith- God is reported in the body, the Divine Krishna- resurrect pedagogy, in which the comic-eschatologiocal Body, Church of Heaven and Earth, The Secret New Substances contain - the salvation of all creation, all creatures animate and inanimate. The salvation of man and the world, in the Divine dispensation and the pedagogy of salvation invation involve all there persons of the Holy

  5. Visual Servoing of Mobile Microrobot with Centralized Camera

    Directory of Open Access Journals (Sweden)

    Kiswanto Gandjar

    2018-01-01

    Full Text Available In this paper, a mechanism of visual servoing for mobile microrobot with a centralized camera is developed. Especially for the development of swarm AI applications. In the fields of microrobots the size of robots is minimal and the amount of movement is also small. By replacing various sensors that is needed with a single centralized vision sensor we can eliminate a lot of components and the need for calibration on every robot. A study and design for a visual servoing mobile microrobot has been developed. This system can use multi object tracking and hough transform to identify the positions of the robots. And can control multiple robots at once with an accuracy of 5-6 pixel from the desired target.

  6. Active Vibration Isolation Devices with Inertial Servo Actuators

    Science.gov (United States)

    Melik-Shakhnazarov, V. A.; Strelov, V. I.; Sofiyanchuk, D. V.; Tregubenko, A. A.

    2018-03-01

    The use of active vibration isolation devices (AVIDs) in aerospace engineering is subject to the following restrictions. First, the volume for installing additional devices is always limited in instrument racks and compartments. Secondly, in many cases, it is impossible to add supports for servo actuators for fundamental or design considerations. In the paper, it has been shown that this problem can be solved if the inertial servo actuators are used in AVIDs instead of reference actuators. A transfer function has been theoretically calculated for an AVID controlled by inertial actuators. It has been shown that the volume of a six-mode single-housing AVID with inertial actuators can be 2-2.5 times smaller than that of devices with support actuators.

  7. The research on algorithms for optoelectronic tracking servo control systems

    Science.gov (United States)

    Zhu, Qi-Hai; Zhao, Chang-Ming; Zhu, Zheng; Li, Kun

    2016-10-01

    The photoelectric servo control system based on PC controllers is mainly used to control the speed and position of the load. This paper analyzed the mathematical modeling and the system identification of the servo system. In the aspect of the control algorithm, the IP regulator, the fuzzy PID, the Active Disturbance Rejection Control (ADRC) and the adaptive algorithms were compared and analyzed. The PI-P control algorithm was proposed in this paper, which not only has the advantages of the PI regulator that can be quickly saturated, but also overcomes the shortcomings of the IP regulator. The control system has a good starting performance and the anti-load ability in a wide range. Experimental results show that the system has good performance under the guarantee of the PI-P control algorithm.

  8. Inherent limitations of fixed time servo-controlled radiometric calorimetry

    International Nuclear Information System (INIS)

    Wetzel, J.R.; Duff, M.F.; Lemming, J.F.

    1987-01-01

    There has been some interest in low precision, short run time calorimetry measurements. This type of calorimetry measurement has been proposed for use when high precision measurements are not required, for example, to screen scrap containers to determine if there is enough material to be measured more accurately of for confirmatory measurements that only require low precision results. The equipment needed to make these measurements is a servo-controlled calorimeter with a sample preequilibration bath. The preequilibration bath temperature is set to the internal temperature of the calorimeter running at a fixed servo-controlled wattage level. The sample power value is determined at a fixed time form the sample loading into the calorimeter. There are some limitations and areas of uncertainties in the use of data obtained by this method. Data collected under controlled conditions demonstrate the limitations. Sample packaging, preequilibration time, and item wattage were chosen as the variables most likely to be encountered in a plant environment

  9. Research on intelligent algorithm of electro - hydraulic servo control system

    Science.gov (United States)

    Wang, Yannian; Zhao, Yuhui; Liu, Chengtao

    2017-09-01

    In order to adapt the nonlinear characteristics of the electro-hydraulic servo control system and the influence of complex interference in the industrial field, using a fuzzy PID switching learning algorithm is proposed and a fuzzy PID switching learning controller is designed and applied in the electro-hydraulic servo controller. The designed controller not only combines the advantages of the fuzzy control and PID control, but also introduces the learning algorithm into the switching function, which makes the learning of the three parameters in the switching function can avoid the instability of the system during the switching between the fuzzy control and PID control algorithms. It also makes the switch between these two control algorithm more smoother than that of the conventional fuzzy PID.

  10. Application of IFT and SPSA to servo system control.

    Science.gov (United States)

    Rădac, Mircea-Bogdan; Precup, Radu-Emil; Petriu, Emil M; Preitl, Stefan

    2011-12-01

    This paper treats the application of two data-based model-free gradient-based stochastic optimization techniques, i.e., iterative feedback tuning (IFT) and simultaneous perturbation stochastic approximation (SPSA), to servo system control. The representative case of controlled processes modeled by second-order systems with an integral component is discussed. New IFT and SPSA algorithms are suggested to tune the parameters of the state feedback controllers with an integrator in the linear-quadratic-Gaussian (LQG) problem formulation. An implementation case study concerning the LQG-based design of an angular position controller for a direct current servo system laboratory equipment is included to highlight the pros and cons of IFT and SPSA from an application's point of view. The comparison of IFT and SPSA algorithms is focused on an insight into their implementation.

  11. Pressure control of hydraulic servo system using proportional control valve

    International Nuclear Information System (INIS)

    Yang, Kyong Uk; Oh, In Ho; Lee, Ill Yeong

    1999-01-01

    The purpose of this study is to develop a control scheme for the hydraulic servo system which can rapidly control the pressure in a hydraulic cylinder with very short stroke. Compared with the negligible stroke of the cylinder in the system, the flow gain of the proportional pressure control valve constituting the hydraulic servo system is relatively large and the time delay on the response of the valve is quite long. Therefore, the pressure control system, in this study tends to get unstable during operations. Considering the above mentioned characteristics of the system, a two-degree-of-freedom control scheme, composed of the I-PDD 2 ... feedback compensator and the feedforward controller, is proposed. The reference model scheme is used in deciding the parameters of the controllers. The validity of the proposed control scheme is confirmed through the experiments

  12. Robust Control for High-Speed Visual Servoing Applications

    DEFF Research Database (Denmark)

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

    2007-01-01

    This paper presents a new control scheme for visual servoing applications. The approach employs quadratic optimization, and explicitly handles both joint position, velocity and acceleration limits. Contrary to existing techniques, our method does not rely on large safety margins and slow task...... execution to avoid joint limits, and is hence able to exploit the full potential of the robot. Furthermore, our control scheme guarantees a well-defined behavior of the robot even when it is in a singular configuration, and thus handles both internal and external singularities robustly. We demonstrate...... the correctness and efficiency of our approach in a number of visual servoing applications, and compare it to a range of previously proposed techniques....

  13. Experimental consideration for realizing image based visual servo control system

    International Nuclear Information System (INIS)

    Ishikawa, N.; Suzuki, K.; Fujii, Y.; Usui, H.

    1995-01-01

    In this study, we consider the experimental aspect of image based visual servo control system. The items considered are the following; 1) Inertial parameter estimation, 2) Focal point estimation, 3) Controller performance for the system with delay. From the experimental result of visual control, it is found that the system is very sensitive to the controller gain because of the computational delay of vision. In order to establish a satisfactory delay compensation, more investigations on controller design are required. (author)

  14. Frequency doubled dye laser with a servo-tuned crystal

    Energy Technology Data Exchange (ETDEWEB)

    Kuhl, J; Spitschan, H

    1975-01-01

    Spectral tuning of the uv output of a frequency doubled dye laser was successfully controlled by a servo motor system which tilts the nonlinear crystal appropriate for phase-matched second harmonic generation while the dye laser emission wavelength is tuned. The spatial direction of the generated uv beam was used as the regulating signal. The feasibility of this technique for spectroscopic applications was successfully tested.

  15. Bookshelf. John Adams biography

    International Nuclear Information System (INIS)

    Billinge, Roy

    1993-01-01

    Full text: When John Bertram Adams died on 3 March 1984, CERN lost one of its principal architects. The late Sir John Adams was a very private person who rarely confided in his colleagues. This made the job of his biographer particularly difficult. Michael Crowley- Milling has succeeded admirably, and has performed a very important service. Is it a potted history of CERN, or the story of the building of the PS, or of the SPS? Yes, all of these, but most of all it is a thoughtful and discerning biography and a fitting tribute to a veritable giant of European science and technology. The sub-title,' Engineer Extraordinary' refers not only to John's outstanding ability as a builder of accelerators, but perhaps even more importantly, as a builder of teams and an 'engineer of opinions'. The book describes how John's attention to detail and intuitive engineering skills developed during the early part of his career, when working in radar research, and how he emerged as a natural leader in the building of the CERN PS. Then later, how his statesmanship enabled him to ''...rescue it (the 300 GeV Programme) from seeming political disaster and nurse it through technical problems to a successful conclusion.'' One crucial part of this process described is the visit to CERN in 1970 by Margaret Thatcher, at that time UK Secretary of State for Education and Science, and her subsequent letters of thanks, not only to Bernard Gregory as Director General, but also to John. It is interesting to speculate to what extent the good impression made on that occasion helped many years later, when as Prime Minister Mrs Thatcher decided that Britain should stay in CERN! After the successful commissioning of the SPS, the book goes on to describe the period when the two CERN Laboratories were merged under two Directors General. Unfortunately I found this part a little too low key, given that John and Leon van Hove presided over what was undoubtedly

  16. Servo control booster system for minimizing following error

    Science.gov (United States)

    Wise, W.L.

    1979-07-26

    A closed-loop feedback-controlled servo system is disclosed which reduces command-to-response error to the system's position feedback resolution least increment, ..delta..S/sub R/, on a continuous real-time basis, for all operational times of consequence and for all operating speeds. The servo system employs a second position feedback control loop on a by exception basis, when the command-to-response error greater than or equal to ..delta..S/sub R/, to produce precise position correction signals. When the command-to-response error is less than ..delta..S/sub R/, control automatically reverts to conventional control means as the second position feedback control loop is disconnected, becoming transparent to conventional servo control means. By operating the second unique position feedback control loop used herein at the appropriate clocking rate, command-to-response error may be reduced to the position feedback resolution least increment. The present system may be utilized in combination with a tachometer loop for increased stability.

  17. Provision of servo-controlled cooling during neonatal transport.

    Science.gov (United States)

    Johnston, Ewen D; Becher, Julie-Clare; Mitchell, Anne P; Stenson, Benjamin J

    2012-09-01

    Therapeutic hypothermia is a time critical intervention for infants who have experienced a hypoxic-ischaemic event. Previously reported methods of cooling during transport do not demonstrate the same stability achieved in the neonatal unit. The authors developed a system which allowed provision of servo-controlled cooling throughout transport, and present their first year's experience. Retrospective review of routinely collected patient data. 14 out-born infants were referred for cooling during a 12-month period. Nine infants were managed with the servo-controlled system during transport. Cooling was commenced in all infants before 6 h of life. Median time from team arrival to the infant having a temperature in the target range (33-34°C) was 45 min. Median temperature during transfer was 33.5°C (range 33-34°C). Temperature on arrival at the cooling centre ranged from 33.4°C to 33.8°C. Servo-controlled cooling during transport is feasible and provides an optimal level of thermal control.

  18. Modeling of R/C Servo Motor and Application to Underactuated Mechanical Systems

    Science.gov (United States)

    Ishikawa, Masato; Kitayoshi, Ryohei; Wada, Takashi; Maruta, Ichiro; Sugie, Toshiharu

    An R/C servo motor is a compact package of a DC geard-motor associated with a position servo controller. They are widely used in small-sized robotics and mechatronics by virtue of their compactness, easiness-to-use and high/weight ratio. However, it is crucial to clarify their internal model (including the embedded position servo) in order to improve control performance of mechatronic systems using R/C servo motors, such as biped robots or underactuted sysyems. In this paper, we propose a simple and realistic internal model of the R/C servo motors including the embedded servo controller, and estimate their physical parameters using continuous-time system identification method. We also provide a model of reference-to-torque transfer function so that we can estimate the internal torque acting on the load.

  19. Application of AC servo motor on the in-core neutron flux instrumentation system

    International Nuclear Information System (INIS)

    Du Xiaoguang; Wang Mingtao

    2010-01-01

    The application of ac servo motor in the In-Core Neutron Flux Instrumentation System is described. The hardware component of ac servo motor control system is different from the dc motor control system. The effect of two control system on the instrumentation system is compared. The ac servo motor control system can improve the accuracy of the motion control, optimize the speed control and increase the reliability. (authors)

  20. A Design Method of Robust Servo Internal Model Control with Control Input Saturation

    OpenAIRE

    山田, 功; 舩見, 洋祐

    2001-01-01

    In the present paper, we examine a design method of robust servo Internal Model Control with control input saturation. First of all, we clarify the condition that Internal Model Control has robust servo characteristics for the system with control input saturation. From this consideration, we propose new design method of Internal Model Control with robust servo characteristics. A numerical example to illustrate the effectiveness of the proposed method is shown.

  1. Modeling and stability of electro-hydraulic servo of hydraulic excavator

    Science.gov (United States)

    Jia, Wenhua; Yin, Chenbo; Li, Guo; Sun, Menghui

    2017-11-01

    The condition of the hydraulic excavator is complicated and the working environment is bad. The safety and stability of the control system is influenced by the external factors. This paper selects hydraulic excavator electro-hydraulic servo system as the research object. A mathematical model and simulation model using AMESIM of servo system is established. Then the pressure and flow characteristics are analyzed. The design and optimization of electro-hydraulic servo system and its application in engineering machinery is provided.

  2. Dreams of pneumatic servo and rail way cars in 2010; 2010 nen noyume kukiatsu servo to tetsudo sharyo

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, K. [Tokyo Precision Instruments Co. Ltd., Kanagawa (Japan)

    2000-01-15

    This paper describes pneumatic servo and railway cars. The comfort of railway cars is improved by reducing excess transverse centrifugal force, and longitudinal, transverse and vertical vibration. Pneumatic system plays a large role in the comfort. Pneumatic system is used for doors because of certain open/shut operation and protecting a hand caught in a door from excess tightening pressure. Pneumatic system is also used for mechanical brakes. Pneumatic spring for car suspensions improves the comfort considerably. The orifice and auxiliary tank of a pneumatic spring reduce a spring constant, and give damping to the vibration system of car bodies and springs. To reduce an outward excess centrifugal force by tilting a car body inward at curve, a body tilting equipment is used which is adopted for a pendulum car with pneumatic servo control, and a tilting car with height control of both side pneumatic springs. For transverse damping, semi-active equipment using oil damper is in wide use, while that using pneumatic servo is also in rial use. (NEDO)

  3. Position Control of Servo Systems Using Feed-Forward Friction Compensation

    International Nuclear Information System (INIS)

    Park, Min Gyu; Kim, Han Me; Shin, Jong Min; Kim, Jong Shik

    2009-01-01

    Friction is an important factor for precise position tracking control of servo systems. Servo systems with highly nonlinear friction are sensitive to the variation of operating condition. To overcome this problem, we use the LuGre friction model which can consider dynamic characteristics of friction. The LuGre friction model is used as a feed-forward compensator to improve tracking performance of servo systems. The parameters of the LuGre friction model are identified through experiments. The experimental result shows that the tracking performance of servo systems with higherly nonlinear friction can be improved by using feed-forward friction compensation

  4. John Bertram Adams

    International Nuclear Information System (INIS)

    Stafford, G.H.

    1986-01-01

    This is the biography of a man obviously much liked and respected. It gives some personal details but is mainly concerned with his scientific work and achievements on major projects. Thus, some background information on those projects is also given as a context to the work of John Adams. The biography is written in sections; early years, the creation of CERN, Adams at CERN 1953-61, Adams and thermonuclear research 1958-69, (which includes his Directorship of the Culham Laboratory), Adams and the Ministry of Technology 1965-66, member for research of the UK Atomic Energy Authority 1966-69, Adams at CERN 1969-84 (as Director General of the SPS, as Executive Director-General of CERN 1979-81 and work at CERN up to 1984). (UK)

  5. Filsafat Multikulturalisme John Rawls

    Directory of Open Access Journals (Sweden)

    Rina Rehayati

    2012-12-01

    Full Text Available Terjadinya konflik horizontal yang mengatasnamakan identitas kelompok (etnis, suku, keyakinan dan seterusnya dikarenakan adanya phobia terhadap perbedaan. Padahal perbedaan suatu keniscayaan, karena manusia tidak akan mampu menyeragamkan atau menuntut orang lain untuk sama dengan dirinya, baik pada aspek pemikiran, keyakinan, etnis, suku, budaya, dan sebagainya. Filsafat multikulturalisme John Rawls merupakan alternatif tawaran politik kebudayaan untuk mengatasi konflik horizontal. Menurut Rawls, suatu masyarakat yang adil bukanlah hanya menjamin “the greatest happiness for the greatest number” yang selama ini terkenal dalam prinsip demokrasi. Tetapi, masyarakat yang adil menurutnya adalah adanya pengakuan dan penerimaan terhadap perbedaan dan keberagaman. Pendapatnya ini dia rangkai dalam pokok-pokok pemikirannya tentang keadilan, seperti: Justice as Fairness, Veil of Ignorance, Principle of Equal Liberty, Maximin Rule, Lexical Order dan Reflective Equilibrium.

  6. All Digital IQ Servo-System for CERN Linacs

    CERN Document Server

    Broere, J; Garoby, R; Rohlev, A; Serrano, J

    2004-01-01

    A VME based control system has been developed and built at CERN for the servo loops regulating the field in linac accelerating structures. It is an all-digital system built on a single VME card, providing digital detection, processing, and modulation. It is foreseen to be used, in different versions, for the needs of both present and future CERN hadron linacs. The first application will be in the energy ramping RF chain of the CERN Heavy Ion Linac (linac 3). Design principle and the experimental results are described.

  7. Rancang Bangun Graphical User Interface Untuk Pergerakan Motor Servo menggunakan Microsoft Visual Basic 2010 Express

    Directory of Open Access Journals (Sweden)

    Anggoro S Pramudyo

    2016-03-01

    Full Text Available Zaman sekarang ini teknologi sedang berkembang pesat dan robot-robot dirancang untuk dapat membantu pekerjaan dan tugas-tugas manusia. Motor servo merupakan salah satu jenis dari motor DC dan banyak diaplikasikan pada dunia robotik maupun peralatan lain, contohnya motor servo yang digunakan untuk robot berkaki. Dalam penggunaannya motor servo dapat bergerak karena ada sinyal yang dibangkitkan melalui sinyal PWM. Sinyal yang dihasilkan akan membentuk sudut sesuai nilai yang diberikan. Penelitian ini bertujuan untuk membuat perangkat lunak GUI untuk membuat pergerakan motor servo menggunakan Microsoft Visual Basic dengan bantuan database menggunakan Microsoft Access. Pergerakan motor servo dapat bergerak secara sekuen dan real time menggunakan GUI yang dihubungkan dengan Arduino mega 2560. Parameter yang terdapat di dalam database juga bisa langsung di-export menjadi file Arduino. Hasil penelitian ini GUI yang telah dibuat dapat menggerakkan motor servo secara lancar melalui komunikasi serial ketika baudrate diatur pada kecepatan 9600 bps. GUI yang dibuat juga menghasilkan sudut untuk motor servo yaitu dari 00 sampai 1800 secara tepat dan akurat, sehingga mempercepat waktu dalam  menentukan sudut untuk pergerakan motor servo yang akan digunakan.

  8. Analysis and Design of Double-sided Air core Linear Servo Motor with Trapezoidal Permanent Magnets

    DEFF Research Database (Denmark)

    Zhang, Yuqiu; Yang, Zilong; Yu, Minghu

    2011-01-01

    In order to reduce the thrust ripple of linear servo system, a double-sided air core permanent magnet linear servo motor with trapezoidal shape permanent magnets (TDAPMLSM) is proposed in this paper. An analytical model of the motor for predicting the magnetic field in the air-gap at no...

  9. Analysis of a biphase-based servo format for hard-disk drives

    NARCIS (Netherlands)

    Makinwa, K.A.A.; Bergmans, J.W.M.; Voorman, J.O.

    2000-01-01

    Biphase modulation in an embedded-servo format for hard-disk drives is investigated. It is shown that for biphase, at the low linear densities typical of servo information, near-maximum-likelihood performance can be attained by a simple bit detector consisting of a full-response linear equalizer and

  10. Modelling and LPV control of an electro-hydraulic servo system

    NARCIS (Netherlands)

    Naus, G.J.L.; Wijnheijmer, F.P.; Post, W.J.A.E.M.; Steinbuch, M.; Teerhuis, A.P.

    2006-01-01

    This paper aims to show the modelling and control of an hydraulic servo system, targeting at frequency domain based controller design and the implementation of a LPV controller. The actual set-up consists of a mass, moved by a hydraulic cylinder and an electro-hydraulic servo valve. A nonlinear

  11. Analysis of the servo-spill control for slow beam extraction

    International Nuclear Information System (INIS)

    Sato, Hikaru; Toyama, Takeshi; Marutsuka, Katsumi; Shirakata, Masashi.

    1994-01-01

    This report describes an analysis of servo-spill control system for the slow beam extraction from the KEK PS. Transfer function of extraction process is derived from measurement of the closed-loop characteristic using measured frequency response of each equipment. Result indicates the restriction of the present servo-spill control and give a guide line for the improvement. (author)

  12. Suppression of mechanical resonance in digital servo system considering oscillation frequency deviation

    DEFF Research Database (Denmark)

    Chen, Yangyang; Yang, Ming; Hu, Kun

    2017-01-01

    High-stiffness servo system is easy to cause mechanical resonance in elastic coupling servo system. Although on-line adaptive notch filter is effective in most cases, it will lead to a severer resonance when resonance frequency deviated from the natural torsional frequency. To explain...

  13. John Adams Lecture

    CERN Multimedia

    PH Department

    2010-01-01

    13 December 2010 14:30 - Council Chamber, Bldg.503-1-001 Accelerator Breakthroughs, Achievements and Lessons from the Tevatron Collider V. Shiltsev / Fermilab’s Accelerator Physics Centre This year we celebrate the 25th anniversary of the first proton-antiproton collisions in the Tevatron. For two and a half decades the Tevatron at Fermilab (Batavia, IL, USA) was a centerpiece of the US and world’s High Energy Physics as the world’s highest energy particle collider at 1.8 TeV center of mass energy. While funding agencies are deciding on a 3-year extension of the Collider Run II operation through 2014, we – in this 2010 John Adams Lecture - will take a look in exciting story of the Tevatron: the story of long preparations, great expectations, numerous difficulties, years of “blood and sweat”, continuous upgrades, exceeding original goals (by a factor of 400) and high emotions. An accelerator scientist prospective will be given on a wide spectrum o...

  14. Strong stabilization servo controller with optimization of performance criteria.

    Science.gov (United States)

    Sarjaš, Andrej; Svečko, Rajko; Chowdhury, Amor

    2011-07-01

    Synthesis of a simple robust controller with a pole placement technique and a H(∞) metrics is the method used for control of a servo mechanism with BLDC and BDC electric motors. The method includes solving a polynomial equation on the basis of the chosen characteristic polynomial using the Manabe standard polynomial form and parametric solutions. Parametric solutions are introduced directly into the structure of the servo controller. On the basis of the chosen parametric solutions the robustness of a closed-loop system is assessed through uncertainty models and assessment of the norm ‖•‖(∞). The design procedure and the optimization are performed with a genetic algorithm differential evolution - DE. The DE optimization method determines a suboptimal solution throughout the optimization on the basis of a spectrally square polynomial and Šiljak's absolute stability test. The stability of the designed controller during the optimization is being checked with Lipatov's stability condition. Both utilized approaches: Šiljak's test and Lipatov's condition, check the robustness and stability characteristics on the basis of the polynomial's coefficients, and are very convenient for automated design of closed-loop control and for application in optimization algorithms such as DE. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Modeling, simulation, and identification of the servo pumps

    Energy Technology Data Exchange (ETDEWEB)

    Negoita, C G; Vasiliu, D; Vasiliu, Ne; Calinoiu, C, E-mail: claudia.negoita@gmail.co [Faculty of Power Engineering, University POLITEHNICA of Bucharest 313, Splaiul Independentei, Bucharest, 060042 (Romania)

    2010-08-15

    This paper contains the results of a systematic research on the steady-state behavior, and the transients occurring in a basic hydrostatic system containing a servo pump. The optimum structure of such a device working in given condition is found step by step, the synthesis stages are alternating with the analysis ones, in order to establish some general synthesis criteria, as well as for creating some images of the design parameters influence on the real system dynamic behavior. The dynamic computation of the servo pumps is based on the experimental researches carried out by the authors on the control force of the variable displacement axial piston pumps. The analysis takes into account the pressure feedback, the rigid or spring mechanical feedback or the electrical position feedback. The theoretical models are developed by AMESim (Advanced Modeling and Simulation Environment for Systems Engineering). The experimental tests were performed by the aid of LabVIEW software from National Instruments Corporation in the frame of a national certified laboratory set up by the aid of Parker Hannifin Corporation.

  16. Control-structure interaction in precision pointing servo loops

    Science.gov (United States)

    Spanos, John T.

    1989-01-01

    The control-structure interaction problem is addressed via stability analysis of a generic linear servo loop model. With the plant described by the rigid body mode and a single elastic mode, structural flexibility is categorized into one of three types: (1) appendage, (2) in-the-loop minimum phase, and (3) in-the-loop nonminimum phase. Closing the loop with proportional-derivative (PD) control action and introducing sensor roll-off dynamics in the feedback path, stability conditions are obtained. Trade studies are conducted with modal frequency, modal participation, modal damping, loop bandwidth, and sensor bandwidth treated as free parameters. Results indicate that appendage modes are most likely to produce instability if they are near the sensor rolloff, whereas in-the-loop modes are most dangerous near the loop bandwidth. The main goal of this paper is to provide a fundamental understanding of the control-structure interaction problem so that it may benefit the design of complex spacecraft and pointing system servo loops. In this framework, the JPL Pathfinder gimbal pointer is considered as an example.

  17. HISTORICAL NOTE JOHN HUNTER (SURGEON) John Hunter FRS ...

    African Journals Online (AJOL)

    JOHN HUNTER (SURGEON). John Hunter FRS (13 February 1728-16 October 1793) was a Scottish surgeon, one of the most distinguished scientists and surgeons of his day. He was an early advocate of careful observation and scientific method in medicine. He was the husband of Anne Hunter, a teacher, friend and ...

  18. Inducement of Design Parameters for Reliability Improvement of Servo Actuator for Hydraulic Valve Operation

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Baek Ju; Kim, Do Sik [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2014-05-15

    The precision hydraulic valve is widely used in various industrial field like aircraft, automobile, and general machinery. Servo actuator is the most important device for driving the precise hydraulic valve. The reliable operation of servo actuator effects on the overall hydraulic system. The performance of servo actuator relies on frequency response and step response according to arbitrary input signal. In this paper, we performed the analysis for the components of servo actuator to satisfy the reliable operation and response characteristics through the reliability analysis, and also induced the design parameters to realize the reliable operation and fast response characteristics of servo actuator for hydraulic valve operation through the empirical knowledge of experts and electromagnetic theories. We suggested the design equations to determine the values of design parameters of servo actuator as like bobbin size, length of yoke and plunger and turn number of coil, and verified the achieved design values through FEM analysis and performance tests using some prototypes of servo actuators adapted in hydraulic valve.

  19. Phase-Division-Based Dynamic Optimization of Linkages for Drawing Servo Presses

    Science.gov (United States)

    Zhang, Zhi-Gang; Wang, Li-Ping; Cao, Yan-Ke

    2017-11-01

    Existing linkage-optimization methods are designed for mechanical presses; few can be directly used for servo presses, so development of the servo press is limited. Based on the complementarity of linkage optimization and motion planning, a phase-division-based linkage-optimization model for a drawing servo press is established. Considering the motion-planning principles of a drawing servo press, and taking account of work rating and efficiency, the constraints of the optimization model are constructed. Linkage is optimized in two modes: use of either constant eccentric speed or constant slide speed in the work segments. The performances of optimized linkages are compared with those of a mature linkage SL4-2000A, which is optimized by a traditional method. The results show that the work rating of a drawing servo press equipped with linkages optimized by this new method improved and the root-mean-square torque of the servo motors is reduced by more than 10%. This research provides a promising method for designing energy-saving drawing servo presses with high work ratings.

  20. Study of Pneumatic Servo Loading System in Double-Sided Polishing

    International Nuclear Information System (INIS)

    Qian, N; Ruan, J; Li, W

    2006-01-01

    The precise double-sided polishing process is one of the main methods to get the ultra-smooth surface of workpiece. In double-sided polishing machine, a loading system is required to be able to precisely control the load superimposed on the workpiece, while the polishing is being carried out. A pneumatic servo loading system is proposed for this purpose. In the pneumatic servo system, the servo valve, which acts both the electrical to mechanical converter and the power amplifier, has a substantial influence on the performance of the loading system. Therefore a specially designed pneumatic digital servo valve is applied in the control system. In this paper, the construction of the pneumatic servo loading system in double-sided polishing machine and control strategy associated with the digital servo valve are first addressed. The mathematical model of the system established and the hardware of the pneumatic servo system is designed. Finally, the experiments are carried out by measuring the practical load on the workpiece and the quality of the surface finish. It is demonstrated that the error rate of load is less than 5% and a super-smooth surface of silicon wafer with roughness Ra 0.401 nm can be obtained

  1. Servo Driven Corotation: Development of AN Inertial Clock.

    Science.gov (United States)

    Cheung, Wah-Kwan Stephen

    An inertial clock to test non-metricity of gravity is proposed here. A first, room-temperature, servo corotation -protected, double magnetically suspended precision rotor system is developed for this purpose. The specific goal was to exhibit the properties of such a clock in its entirety at whatever level of precision was achievable. A monolithic system has been completed for these preliminary studies. It includes particular development of individual experimental sub-systems (a hybrid double magnetic suspension; a diffusion pumping system; a microcomputer -controlled eddy-current drive system; and the angular period measuring schemes for the doubly suspended rotors). Double magnetic suspension had been investigated by Beams for other purposes. The upper transducer is optical but parametrized and the lower transducer employs the frequency modulation characteristic of a LC tank circuit. The doubly suspended rotors corotate so that the upper rotor is servoed to rotate at the same angular velocity as that of the lower rotor. This creates a "drag free" environment for the lower rotor and effectively eliminates the gas drag on the lower rotor. Consequently, the decay time constant of the lower rotor increases. With other means of protection, the lower rotor will then, with perfect system operation, suffer no drag and therefore become the inertial time keeper. A commercial microcomputer is introduced to execute the servo-corotation. The tests thus far are, with one exception, run at atmospheric pressure. An idealized analysis for open and closed loop corotation is shown. Such analysis includes only the viscous drag acting on the corotating rotors. The analysis suggests that angular position control be added to the present feedback drive which is of derivative nature only. Open and closed corotation runs show that a strong torsional coupling besides that of the gas drag exists between the rotors. When misalignment of the support pole pieces is deliberately made significant

  2. Conceptual design of stepper motor replacing servo motor for control rod controller

    International Nuclear Information System (INIS)

    Mohd Dzul Aiman Aslan; Mohd Idris Taib; Izhar Abu Hussin; Mohd Khairulezwan Abdul Manan; Mohd Sabri Minhat

    2010-01-01

    In PUSPATI TRIGA Reactor, current control rod controller are using servo motor to control the movement. Control rod is a very important safety element and measure in every nuclear reactor. So, precision is very important in measurement of security in the nuclear reactor. In this case, there are a few disadvantages when using the servo motor is measurement of the motor is not precise. One solution to overcome this is by shifting servo motor with stepper motor. A stepper motor (or step motor) is a brush less, synchronous electric motor that can divide a full rotation into a large number of steps. (author)

  3. Fuzzy model-based servo and model following control for nonlinear systems.

    Science.gov (United States)

    Ohtake, Hiroshi; Tanaka, Kazuo; Wang, Hua O

    2009-12-01

    This correspondence presents servo and nonlinear model following controls for a class of nonlinear systems using the Takagi-Sugeno fuzzy model-based control approach. First, the construction method of the augmented fuzzy system for continuous-time nonlinear systems is proposed by differentiating the original nonlinear system. Second, the dynamic fuzzy servo controller and the dynamic fuzzy model following controller, which can make outputs of the nonlinear system converge to target points and to outputs of the reference system, respectively, are introduced. Finally, the servo and model following controller design conditions are given in terms of linear matrix inequalities. Design examples illustrate the utility of this approach.

  4. Decommissioning of hot cells using a hydraulically powered servo manipulator

    International Nuclear Information System (INIS)

    Asquith, J.D.; Loughborough, D.

    1993-01-01

    This paper describes the preparations and initial trials involved in remotely dismantling the containment boxes within two concrete shielded hot cells at Harwell Laboratory using a hydraulically powered servo manipulator, ARTISAN. The manipulator deploys a variety of tools for cutting operations. The modular design has enabled it to be specifically configured for this application by adjusting the link lengths using spacers between the joints. In addition to the remote handling requirements, a new posting and ventilation system for the facility is outlined. Trials with ARTISAN in an in-active mock-up have now been successfully completed, and the manipulator is installed in the active facility. The considerations and approach adopted in this project are typical of many situations where remote techniques are required for decommissioning activities. (author)

  5. All Digital IQ Servo-System for CERN Linacs

    CERN Document Server

    Rohlev, A; Garoby, R

    2003-01-01

    A new VME based system has been developed and built at CERN for the servo loops regulating the field in the linac accelerating structure. It makes use of high speed digital In-phase/Quadrature (IQ) detection, digital processing, and digital IQ modulation. The digital processing and IQ modulation is done in a single PLD. The system incorporates continually variable set points, iterative learning, feed forward as well as extensive diagnostics and other features well suited for digital implementations. Built on a single VME card, it will be first used in the energy ramping RF chain of the CERN Heavy Ion Linac (linac 3) and later for upgrading the present proton linac (linac 2). This system serves also as a prototype for the future Superconducting Proton Linac (SPL). The design principle and the experimental results are described.

  6. Visual servo simulation of EAST articulated maintenance arm robot

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang, E-mail: yangyang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, 350 Shushanhu Rd, Hefei, Anhui (China); Song, Yuntao; Pan, Hongtao; Cheng, Yong; Feng, Hansheng [Institute of Plasma Physics, Chinese Academy of Sciences, 350 Shushanhu Rd, Hefei, Anhui (China); Wu, Huapeng [Lappeenranta University of Technology, Skinnarilankatu 34, Lappeenranta (Finland)

    2016-03-15

    For the inspection and light-duty maintenance of the vacuum vessel in the EAST tokamak, a serial robot arm, called EAST articulated maintenance arm, is developed. Due to the 9-m-long cantilever arm, the large flexibility of the EAMA robot introduces a problem in the accurate positioning. This article presents an autonomous robot control to cope with the robot positioning problem, which is a visual servo approach in context of tile grasping for the EAMA robot. In the experiments, the proposed method was implemented in a simulation environment to position and track a target graphite tile with the EAMA robot. As a result, the proposed visual control scheme can successfully drive the EAMA robot to approach and track the target tile until the robot reaches the desired position. Furthermore, the functionality of the simulation software presented in this paper is proved to be suitable for the development of the robotic and computer vision application.

  7. Visual servo simulation of EAST articulated maintenance arm robot

    International Nuclear Information System (INIS)

    Yang, Yang; Song, Yuntao; Pan, Hongtao; Cheng, Yong; Feng, Hansheng; Wu, Huapeng

    2016-01-01

    For the inspection and light-duty maintenance of the vacuum vessel in the EAST tokamak, a serial robot arm, called EAST articulated maintenance arm, is developed. Due to the 9-m-long cantilever arm, the large flexibility of the EAMA robot introduces a problem in the accurate positioning. This article presents an autonomous robot control to cope with the robot positioning problem, which is a visual servo approach in context of tile grasping for the EAMA robot. In the experiments, the proposed method was implemented in a simulation environment to position and track a target graphite tile with the EAMA robot. As a result, the proposed visual control scheme can successfully drive the EAMA robot to approach and track the target tile until the robot reaches the desired position. Furthermore, the functionality of the simulation software presented in this paper is proved to be suitable for the development of the robotic and computer vision application.

  8. Velocity control of servo systems using an integral retarded algorithm.

    Science.gov (United States)

    Ramírez, Adrián; Garrido, Rubén; Mondié, Sabine

    2015-09-01

    This paper presents a design technique for the delay-based controller called Integral Retarded (IR), and its applications to velocity control of servo systems. Using spectral analysis, the technique yields a tuning strategy for the IR by assigning a triple real dominant root for the closed-loop system. This result ultimately guarantees a desired exponential decay rate σ(d) while achieving the IR tuning as explicit function of σ(d) and system parameters. The intentional introduction of delay allows using noisy velocity measurements without additional filtering. The structure of the controller is also able to avoid velocity measurements by using instead position information. The IR is compared to a classical PI, both tested in a laboratory prototype. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Myoelectric hand prosthesis force control through servo motor current feedback.

    Science.gov (United States)

    Sono, Tálita Saemi Payossim; Menegaldo, Luciano Luporini

    2009-10-01

    This paper presents the prehension force closed-loop control design of a mechanical finger commanded by electromyographic signal (EMG) from a patient's arm. The control scheme was implemented and tested in a mechanical finger prototype with three degrees of freedom and one actuator, driven by arm muscles EMG of normal volunteers. Real-time indirect estimation of prehension force was assessed by measuring the DC servo motor actuator current. A model of the plant comprising finger, motor, and grasped object was proposed. Model parameters were identified experimentally and a classical feedback phase-lead compensator was designed. The controlled mechanical finger was able to provide a more accurate prehension force modulation of a compliant object when compared to open-loop control.

  10. Adaptive integral robust control and application to electromechanical servo systems.

    Science.gov (United States)

    Deng, Wenxiang; Yao, Jianyong

    2017-03-01

    This paper proposes a continuous adaptive integral robust control with robust integral of the sign of the error (RISE) feedback for a class of uncertain nonlinear systems, in which the RISE feedback gain is adapted online to ensure the robustness against disturbances without the prior bound knowledge of the additive disturbances. In addition, an adaptive compensation integrated with the proposed adaptive RISE feedback term is also constructed to further reduce design conservatism when the system also exists parametric uncertainties. Lyapunov analysis reveals the proposed controllers could guarantee the tracking errors are asymptotically converging to zero with continuous control efforts. To illustrate the high performance nature of the developed controllers, numerical simulations are provided. At the end, an application case of an actual electromechanical servo system driven by motor is also studied, with some specific design consideration, and comparative experimental results are obtained to verify the effectiveness of the proposed controllers. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Nonlinear control for a class of hydraulic servo system.

    Science.gov (United States)

    Yu, Hong; Feng, Zheng-jin; Wang, Xu-yong

    2004-11-01

    The dynamics of hydraulic systems are highly nonlinear and the system may be subjected to non-smooth and discontinuous nonlinearities due to directional change of valve opening, friction, etc. Aside from the nonlinear nature of hydraulic dynamics, hydraulic servo systems also have large extent of model uncertainties. To address these challenging issues, a robust state-feedback controller is designed by employing backstepping design technique such that the system output tracks a given signal arbitrarily well, and all signals in the closed-loop system remain bounded. Moreover, a relevant disturbance attenuation inequality is satisfied by the closed-loop signals. Compared with previously proposed robust controllers, this paper's robust controller based on backstepping recursive design method is easier to design, and is more suitable for implementation.

  12. Fuzzy self-learning control for magnetic servo system

    Science.gov (United States)

    Tarn, J. H.; Kuo, L. T.; Juang, K. Y.; Lin, C. E.

    1994-01-01

    It is known that an effective control system is the key condition for successful implementation of high-performance magnetic servo systems. Major issues to design such control systems are nonlinearity; unmodeled dynamics, such as secondary effects for copper resistance, stray fields, and saturation; and that disturbance rejection for the load effect reacts directly on the servo system without transmission elements. One typical approach to design control systems under these conditions is a special type of nonlinear feedback called gain scheduling. It accommodates linear regulators whose parameters are changed as a function of operating conditions in a preprogrammed way. In this paper, an on-line learning fuzzy control strategy is proposed. To inherit the wealth of linear control design, the relations between linear feedback and fuzzy logic controllers have been established. The exercise of engineering axioms of linear control design is thus transformed into tuning of appropriate fuzzy parameters. Furthermore, fuzzy logic control brings the domain of candidate control laws from linear into nonlinear, and brings new prospects into design of the local controllers. On the other hand, a self-learning scheme is utilized to automatically tune the fuzzy rule base. It is based on network learning infrastructure; statistical approximation to assign credit; animal learning method to update the reinforcement map with a fast learning rate; and temporal difference predictive scheme to optimize the control laws. Different from supervised and statistical unsupervised learning schemes, the proposed method learns on-line from past experience and information from the process and forms a rule base of an FLC system from randomly assigned initial control rules.

  13. A New Reading of Shakespeare's King John.

    Science.gov (United States)

    Usher, Peter D.

    1995-12-01

    Shakespeare wrote King John c.1594, six years after the defeat of the Spanish Armada, and ~ 50 years after publication of the Copernican heliocentric hypothesis. It is said to be the most unhistorical of the History Plays, ``anomalous'', ``puzzling'', and ``odd'', and as such it has engendered far more than the customary range of interpretive opinion. I suggest that the play alerts Elizabethans not just to military and political threats, but to a changing cosmic world view, all especially threatening as they arise in Catholic countries. (a) Personification characterizes the play. John personifies the old order, while Arthur and the Dauphin's armies personify the new. I suggest that Shakespeare decenters King John just as Copernicus decentered the world. (b) Hubert menaces Arthur's eyes for a whole scene (4.1), but the need for such cruelty is not explained and is especially odd as Arthur is already under sentence of death (3.3.65-66). This hitherto unexplained anomaly suggests that the old order fears what the new might see. (c) Eleanor's confession is made only to Heaven and to her son the King (1.1.42-43), yet by echoing and word play the Messenger from France later reveals to John that he is privy to it (4.2.119-124). This circumstance has not been questioned heretofore. I suggest that the Messenger is like the wily Hermes (Mercury), chief communicator of the gods and patron of the sciences; by revealing that he moves in the highest circles, he tells John that he speaks with an authority that transcends even that of a king. The message from on high presages more than political change; it warns of a new cosmic and religious world order (d) Most agree that John is a weak king, so Shakespeare must have suspected flaws in the old ways. He would have known that Tycho Brahe's new star of 1572, the comet of 1577, and the 1576 model of his compatriot Thomas Digges, were shattering old ideas. (e) The tensions of the play are not resolved because in 1594 the new order was

  14. Genealogy of John and Charles Bell: their relationship with the children of Charles Shaw of Ayr.

    Science.gov (United States)

    Kaufman, M

    2005-11-01

    The Reverend William Bell had six children who survived infancy. Two of his sons entered the legal profession and two other sons became distinguished anatomists and surgeons--John Bell, said for 20 years to have been the leading operating surgeon in Britain and throughout the world--and Sir Charles Bell, possibly the most distinguished anatomist and physiologist of his day. Information is not known about the fifth son or their sister. Charles Shaw, a lawyer of Ayr, had four sons and two daughters who survived infancy. Two of his sons, John and Alexander, became anatomists and later surgeons at the Middlesex Hospital, and both worked closely with Charles Bell at the Great Windmill Street School of Anatomy. His third son entered the law and his fourth son became a distinguished soldier. The two daughters of Charles Shaw married into the Bell family: Barbara married George Joseph Bell and Marion married Mr (later Sir) Charles Bell.

  15. Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

    International Nuclear Information System (INIS)

    Kim, Hyo-gon; Han, Changsoo; Lee, Jong-won; Park, Sangdeok

    2015-01-01

    Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program

  16. Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo-gon; Han, Changsoo [Hanyang University, Seoul (Korea, Republic of); Lee, Jong-won [Korea University of Science and Technology, Seoul (Korea, Republic of); Park, Sangdeok [Korea Institute of Industrial Technology, Seoul (Korea, Republic of)

    2015-02-15

    Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program.

  17. Autonomous docking control of visual-servo type underwater vehicle system aiming at underwater automatic charging

    International Nuclear Information System (INIS)

    Yanou, Akira; Ohnishi, Shota; Ishiyama, Shintaro; Minami, Mamoru

    2015-01-01

    A visual-servo type remotely operated vehicle (ROV) system with binocular wide-angle lens was developed to survey submarine resources, decontaminate radiation from mud in dam lake and so on. This paper explores the experiments on regulator performance and underwater docking of the robot system utilizing Genetic Algorithm (GA) for real-time recognition of the robot's relative position and posture through 3D marker. The visual servoing performances have been verified as follows; (1) The stability performances of the proposed regulator system have been evaluated by exerting abrupt distrubane force while the ROV is controlled by visual servoing. (2) The proposed system can track time-variant desired target position in x-axis (front-back direction of the robot). (3) The underwater docking can be completed by switching visual servoing and docking modes based on the error threshold, and by giving time-varying desired target position and orientation to the controller as a desired pose. (author)

  18. An open source digital servo for atomic, molecular, and optical physics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Leibrandt, D. R., E-mail: david.leibrandt@nist.gov; Heidecker, J. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2015-12-15

    We describe a general purpose digital servo optimized for feedback control of lasers in atomic, molecular, and optical physics experiments. The servo is capable of feedback bandwidths up to roughly 1 MHz (limited by the 320 ns total latency); loop filter shapes up to fifth order; multiple-input, multiple-output control; and automatic lock acquisition. The configuration of the servo is controlled via a graphical user interface, which also provides a rudimentary software oscilloscope and tools for measurement of system transfer functions. We illustrate the functionality of the digital servo by describing its use in two example scenarios: frequency control of the laser used to probe the narrow clock transition of {sup 27}Al{sup +} in an optical atomic clock, and length control of a cavity used for resonant frequency doubling of a laser.

  19. Permanent magnet synchronous motor servo system control based on μC/OS

    Science.gov (United States)

    Shi, Chongyang; Chen, Kele; Chen, Xinglong

    2015-10-01

    When Opto-Electronic Tracking system operates in complex environments, every subsystem must operate efficiently and stably. As a important part of Opto-Electronic Tracking system, the performance of PMSM(Permanent Magnet Synchronous Motor) servo system affects the Opto-Electronic Tracking system's accuracy and speed greatly[1][2]. This paper applied embedded real-time operating system μC/OS to the control of PMSM servo system, implemented SVPWM(Space Vector Pulse Width Modulation) algorithm in PMSM servo system, optimized the stability of PMSM servo system. Pointing on the characteristics of the Opto-Electronic Tracking system, this paper expanded μC/OS with software redundancy processes, remote debugging and upgrading. As a result, the Opto- Electronic Tracking system performs efficiently and stably.

  20. Mathematical-model study of servo system with pulse-duration control of micromovements

    International Nuclear Information System (INIS)

    Dement'eva, M.A.; Leonov, A.P.; Popov, V.V.; Skugarevskii, A.I.; Ustinov, E.A.; Chernyavskii, N.N.

    1988-01-01

    A number of digital servo systems with pulse-duration control have been developed at the Institute of High Energy Physics for the instruments of the scanning and measurement system and various experimental setups. They are based on stock transistor bridge stages, whose loads are high-speed servomotors with printed-circuit armature windings. Study of these servo systems by traditional methods, which are based on Laplace transforms, or by mean values with expansion of the current pulse into a Fourier transform yields approximate results and does not reflect the actual processes that take place in a pulse servo system. They attempt to develop a method and extend it to the study of high-speed servo systems in the area of micromovements and quasistationary velocity without position or velocity feedback

  1. Servo-Drive Amplifier for Micro-Satellite Superconductor-Levitated Flywheels, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A new servo-drive technology is available to support energy storage and navigation for micro-satellites. Exploiting the ?pinning? effect of high-temperature...

  2. An open source digital servo for atomic, molecular, and optical physics experiments

    Science.gov (United States)

    Leibrandt, D. R.; Heidecker, J.

    2015-12-01

    We describe a general purpose digital servo optimized for feedback control of lasers in atomic, molecular, and optical physics experiments. The servo is capable of feedback bandwidths up to roughly 1 MHz (limited by the 320 ns total latency); loop filter shapes up to fifth order; multiple-input, multiple-output control; and automatic lock acquisition. The configuration of the servo is controlled via a graphical user interface, which also provides a rudimentary software oscilloscope and tools for measurement of system transfer functions. We illustrate the functionality of the digital servo by describing its use in two example scenarios: frequency control of the laser used to probe the narrow clock transition of 27Al+ in an optical atomic clock, and length control of a cavity used for resonant frequency doubling of a laser.

  3. Piloted Simulator Investigation of Techniques to Achieve Attitude Command Response with Limited Authority Servos

    National Research Council Canada - National Science Library

    Key, David

    2002-01-01

    The purpose of the study was to develop generic design principles for obtaining attitude command response in moderate to aggressive maneuvers without increasing SCAS series servo authority from the existing +/- 10...

  4. Visual Servo Tracking Control of a Wheeled Mobile Robot with a Monocular Fixed Camera

    National Research Council Canada - National Science Library

    Chen, J; Dixon, W. E; Dawson, D. M; Chitrakaran, V. K

    2004-01-01

    In this paper, a visual servo tracking controller for a wheeled mobile robot (WMR) is developed that utilizes feedback from a monocular camera system that is mounted with a fixed position and orientation...

  5. Preterm infant thermal care: differing thermal environments produced by air versus skin servo-control incubators.

    Science.gov (United States)

    Thomas, K A; Burr, R

    1999-06-01

    Incubator thermal environments produced by skin versus air servo-control were compared. Infant abdominal skin and incubator air temperatures were recorded from 18 infants in skin servo-control and 14 infants in air servo-control (26- to 29-week gestational age, 14 +/- 2 days postnatal age) for 24 hours. Differences in incubator and infant temperature, neutral thermal environment (NTE) maintenance, and infant and incubator circadian rhythm were examined using analysis of variance and scatterplots. Skin servo-control resulted in more variable air temperature, yet more stable infant temperature, and more time within the NTE. Circadian rhythm of both infant and incubator temperature differed by control mode and the relationship between incubator and infant temperature rhythms was a function of control mode. The differences between incubator control modes extend beyond temperature stability and maintenance of NTE. Circadian rhythm of incubator and infant temperatures is influenced by incubator control.

  6. An open source digital servo for atomic, molecular, and optical physics experiments

    International Nuclear Information System (INIS)

    Leibrandt, D. R.; Heidecker, J.

    2015-01-01

    We describe a general purpose digital servo optimized for feedback control of lasers in atomic, molecular, and optical physics experiments. The servo is capable of feedback bandwidths up to roughly 1 MHz (limited by the 320 ns total latency); loop filter shapes up to fifth order; multiple-input, multiple-output control; and automatic lock acquisition. The configuration of the servo is controlled via a graphical user interface, which also provides a rudimentary software oscilloscope and tools for measurement of system transfer functions. We illustrate the functionality of the digital servo by describing its use in two example scenarios: frequency control of the laser used to probe the narrow clock transition of 27 Al + in an optical atomic clock, and length control of a cavity used for resonant frequency doubling of a laser

  7. Investigation of the low flux servo-controlled limit of a co-phased interferometer

    Science.gov (United States)

    Damé, Luc; Derrien, Marc; Kozlowski, Mathias; Merdjane, Mohamed

    2018-04-01

    This paper, "Investigation of the low flux servo-controlled limit of a co-phased interferometer," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France.

  8. Cuidados invisibles: ¿son suficientemente reconocidos?

    Directory of Open Access Journals (Sweden)

    Rosanna de la Rosa Eduardo

    Full Text Available Los cuidados invisibles son un elemento central y fundamental de la práctica de la Enfermería y son la base de su identidad profesional. La Enfermería ha sufrido un importante y positivo proceso de profesionalización en los últimos 150 años, sin embargo, los cuidados invisibles siguen siendo poco reconocidos, a pesar de su importancia en la recuperación y en la calidad de vida de los usuarios. En este trabajo se analizan brevemente las grandes transformaciones sociales actuales que obligan a replantearse la necesidad de visibilizar los cuidados invisibles, se plantean interrogantes clave para abordar esta discusión y se proponen una serie de acciones concretas para avanzar en este reconocimiento.

  9. A deterministic - approach controller design for electrohydraulic position servo control system

    International Nuclear Information System (INIS)

    Johari Osman

    2000-01-01

    This paper is concerned with the design of a tracking controller for controlling electrohydraulic position servo system based on a deterministic approach. The system is treated as an uncertain system with bounded uncertainties where the bounds are assumed known. It will be shown that the electrohydraulic position servo systems with the proposed controller is practically stable and tracks the desired position in spite of the uncertainties and nonlinearities present in the system (author)

  10. Adaptive fuzzy PID control of hydraulic servo control system for large axial flow compressor

    Science.gov (United States)

    Wang, Yannian; Wu, Peizhi; Liu, Chengtao

    2017-09-01

    To improve the stability of the large axial compressor, an efficient and special intelligent hydraulic servo control system is designed and implemented. The adaptive fuzzy PID control algorithm is used to control the position of the hydraulic servo cylinder steadily, which overcomes the drawback that the PID parameters should be adjusted based on the different applications. The simulation and the test results show that the system has a better dynamic property and a stable state performance.

  11. Magic moments with John Bell

    Energy Technology Data Exchange (ETDEWEB)

    Bertlmann, Reinhold A.

    2015-07-15

    John Bell, with whom I had a fruitful collaboration and warm friendship, is best known for his seminal work on the foundations of quantum physics, but he also made outstanding contributions to particle physics and accelerator physics.

  12. Magic moments with John Bell

    International Nuclear Information System (INIS)

    Bertlmann, Reinhold A.

    2015-01-01

    John Bell, with whom I had a fruitful collaboration and warm friendship, is best known for his seminal work on the foundations of quantum physics, but he also made outstanding contributions to particle physics and accelerator physics

  13. Active-passive hybrid piezoelectric actuators for high-precision hard disk drive servo systems

    Science.gov (United States)

    Chan, Kwong Wah; Liao, Wei-Hsin

    2006-03-01

    Positioning precision is crucial to today's increasingly high-speed, high-capacity, high data density, and miniaturized hard disk drives (HDDs). The demand for higher bandwidth servo systems that can quickly and precisely position the read/write head on a high track density becomes more pressing. Recently, the idea of applying dual-stage actuators to track servo systems has been studied. The push-pull piezoelectric actuated devices have been developed as micro actuators for fine and fast positioning, while the voice coil motor functions as a large but coarse seeking. However, the current dual-stage actuator design uses piezoelectric patches only without passive damping. In this paper, we propose a dual-stage servo system using enhanced active-passive hybrid piezoelectric actuators. The proposed actuators will improve the existing dual-stage actuators for higher precision and shock resistance, due to the incorporation of passive damping in the design. We aim to develop this hybrid servo system not only to increase speed of track seeking but also to improve precision of track following servos in HDDs. New piezoelectrically actuated suspensions with passive damping have been designed and fabricated. In order to evaluate positioning and track following performances for the dual-stage track servo systems, experimental efforts are carried out to implement the synthesized active-passive suspension structure with enhanced piezoelectric actuators using a composite nonlinear feedback controller.

  14. CLFs-based optimization control for a class of constrained visual servoing systems.

    Science.gov (United States)

    Song, Xiulan; Miaomiao, Fu

    2017-03-01

    In this paper, we use the control Lyapunov function (CLF) technique to present an optimized visual servo control method for constrained eye-in-hand robot visual servoing systems. With the knowledge of camera intrinsic parameters and depth of target changes, visual servo control laws (i.e. translation speed) with adjustable parameters are derived by image point features and some known CLF of the visual servoing system. The Fibonacci method is employed to online compute the optimal value of those adjustable parameters, which yields an optimized control law to satisfy constraints of the visual servoing system. The Lyapunov's theorem and the properties of CLF are used to establish stability of the constrained visual servoing system in the closed-loop with the optimized control law. One merit of the presented method is that there is no requirement of online calculating the pseudo-inverse of the image Jacobian's matrix and the homography matrix. Simulation and experimental results illustrated the effectiveness of the method proposed here. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  15. John locke on personal identity.

    Science.gov (United States)

    Nimbalkar, Namita

    2011-01-01

    John Locke speaks of personal identity and survival of consciousness after death. A criterion of personal identity through time is given. Such a criterion specifies, insofar as that is possible, the necessary and sufficient conditions for the survival of persons. John Locke holds that personal identity is a matter of psychological continuity. He considered personal identity (or the self) to be founded on consciousness (viz. memory), and not on the substance of either the soul or the body.

  16. John Locke on Personal Identity**

    OpenAIRE

    Nimbalkar, Namita

    2011-01-01

    John Locke speaks of personal identity and survival of consciousness after death. A criterion of personal identity through time is given. Such a criterion specifies, insofar as that is possible, the necessary and sufficient conditions for the survival of persons. John Locke holds that personal identity is a matter of psychological continuity. He considered personal identity (or the self) to be founded on consciousness (viz. memory), and not on the substance of either the soul or the body.

  17. SON68 glass alteration enhanced by magnetite

    Energy Technology Data Exchange (ETDEWEB)

    Godon, Nicole; Gin, Stephane; Rebiscoul, Diane; Frugier, Pierre [CEA, DEN-Marcoule, F30207, Bagnols-sur-Ceze (France)

    2013-07-01

    This paper reports experimental and modeling results of SON68 glass / magnetite interactions while in contact with synthetic groundwater from a clay environment. It is shown that magnetite enhances glass alteration, first by the sorption of Si released from the glass onto magnetite surfaces, then by a second process that could be the precipitation of an iron silicate mineral or the transformation of magnetite into a more reactive phase like hematite or goethite. This study globally suggests a detrimental effect of magnetite on the long-term durability of nuclear glass in geological disposal conditions. (authors)

  18. ?Cuales son las amenazas o peligros volcanicos?

    Science.gov (United States)

    Myers, Bobbie; Brantley, Steven R.; Stauffer, Peter; Hendley, James W.

    2000-01-01

    Los volcanes son capaces de producir numerosos peligros geologicos e hidrologicos. Los cientificos del Servicio Geologico de los EE. UU. (USGS, por sus siglas en ingles) y de otras instituciones alrededor del mundo estan estudiando los peligros de muchos de los centenares de volcanes activos y potencialmente activos del mundo. Estos cientificos vigilan muy de cerca la actividad de algunos de los volcanes mas peligrosos, por lo que estan preparados para alertar a las autoridades y/o a la poblacion en caso de que aumente sustancialmente la probabilidad de que ocurra una erupcion u otro evento peligroso.

  19. John Napier life, logarithms, and legacy

    CERN Document Server

    Havil, Julian

    2014-01-01

    John Napier (1550–1617) is celebrated today as the man who invented logarithms—an enormous intellectual achievement that would soon lead to the development of their mechanical equivalent in the slide rule: the two would serve humanity as the principal means of calculation until the mid-1970s. Yet, despite Napier’s pioneering efforts, his life and work have not attracted detailed modern scrutiny. John Napier is the first contemporary biography to take an in-depth look at the multiple facets of Napier’s story: his privileged position as the eighth Laird of Merchiston and the son of influential Scottish landowners; his reputation as a magician who dabbled in alchemy; his interest in agriculture; his involvement with a notorious outlaw; his staunch anti-Catholic beliefs; his interactions with such peers as Henry Briggs, Johannes Kepler, and Tycho Brahe; and, most notably, his estimable mathematical legacy. Julian Havil explores Napier’s original development of logarithms, the motivations for his approa...

  20. My Son 22.10.11

    Directory of Open Access Journals (Sweden)

    Rebecca Baillie

    2013-01-01

    Full Text Available 'My Son 22.10.11' was made immediately following a miscarriage 8 weeks into pregnancy. After bleeding lightly for a couple of hours, I went to the toilet and a large bloody mass fell from within me. I knew that I could not flush this away, and that to retrieve the mass was my only chance to connect with the unborn foetus. I fished the contents from the bottom of the toilet bowl using my hands and carried them into my small studio. I found some paper and began to dissect the mass. At the centre, I found the tiny, cold, hard foetus. I kissed it and then began to use it as a kind of painting tool, drawing the outline of the lost child using its very own flesh and blood. I knew that to create a lasting and tangible portrait of 'my son' was the best way to understand the somewhat unreal and fleeting experience of miscarriage. I thought of Frida Kahlo while making the work, thinking 'thank God' that I had a reference to miscarriage before it happened to me. I also thought of my childhood days spent on our family pig farm, and of all the dead pig foetuses that I had seen at various stages of development. Before the miscarriage, I thought little about the subject; afterwards, I recognise the profundity of the creation of a life that is never born. The experience is so common, yet so very rarely discussed or depicted.

  1. Panoramic optical-servoing for industrial inspection and repair

    Science.gov (United States)

    Sallinger, Christian; O'Leary, Paul; Retschnig, Alexander; Kammerhofer, Martin

    2004-05-01

    Recently specialized robots were introduced to perform the task of inspection and repair in large cylindrical structures such as ladles, melting furnaces and converters. This paper reports on the image processing system and optical servoing for one such a robot. A panoramic image of the vessels inner surface is produced by performing a coordinated robot motion and image acquisition. The level of projective distortion is minimized by acquiring a high density of images. Normalized phase correlation calculated via the 2D Fourier transform is used to calculate the shift between the single images. The narrow strips from the dense image map are then stitched together to build the panorama. The mapping between the panoramic image and the positioning of the robot is established during the stitching of the images. This enables optical feedback. The robots operator can locate a defect on the surface by selecting the area of the image. Calculation of the forward and inverse kinematics enable the robot to automatically move to the location on the surface requiring repair. Experimental results using a standard 6R industrial robot have shown the full functionality of the system concept. Finally, were test measurements carried out successfully, in a ladle at a temperature of 1100° C.

  2. Cylinder Position Servo Control Based on Fuzzy PID

    Directory of Open Access Journals (Sweden)

    Shibo Cai

    2013-01-01

    Full Text Available The arbitrary position control of cylinder has always been the hard challenge in pneumatic system. We try to develop a cylinder position servo control method by combining fuzzy PID with the theoretical model of the proportional valve-controlled cylinder system. The pressure differential equation of cylinder, pressure-flow equation of proportional valve, and moment equilibrium equation of cylinder are established. And the mathematical models of the cylinder driving system are linearized. Then fuzzy PID control algorithm is designed for the cylinder position control, including the detail analysis of fuzzy variables and domain, fuzzy logic rules, and defuzzification. The stability of the proposed fuzzy PID controller is theoretically proved according to the small gain theorem. Experiments for targets position of 250 mm, 300 mm, and 350 mm were done and the results showed that the absolute error of the position control is less than 0.25 mm. And comparative experiment between fuzzy PID and classical PID verified the advantage of the proposed algorithm.

  3. Sinusoidal visuomotor tracking: intermittent servo-control or coupled oscillations?

    Science.gov (United States)

    Russell, D M; Sternad, D

    2001-12-01

    In visuomotor tasks that involve accuracy demands, small directional changes in the trajectories have been taken as evidence of feedback-based error corrections. In the present study variability, or intermittency, in visuomanual tracking of sinusoidal targets was investigated. Two lines of analyses were pursued: First, the hypothesis that humans fundamentally act as intermittent servo-controllers was re-examined, probing the question of whether discontinuities in the movement trajectory directly imply intermittent control. Second, an alternative hypothesis was evaluated: that rhythmic tracking movements are generated by entrainment between the oscillations of the target and the actor, such that intermittency expresses the degree of stability. In 2 experiments, participants (N = 6 in each experiment) swung 1 of 2 different hand-held pendulums, tracking a rhythmic target that oscillated at different frequencies with a constant amplitude. In 1 line of analyses, the authors tested the intermittency hypothesis by using the typical kinematic error measures and spectral analysis. In a 2nd line, they examined relative phase and its variability, following analyses of rhythmic interlimb coordination. The results showed that visually guided corrective processes play a role, especially for slow movements. Intermittency, assessed as frequency and power components of the movement trajectory, was found to change as a function of both target frequency and the manipulandum's inertia. Support for entrainment was found in conditions in which task frequency was identical to or higher than the effector's eigenfrequency. The results suggest that it is the symmetry between task and effector that determines which behavioral regime is dominant.

  4. Use of servo controlled weld head for end closure welding

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, S.K.; Setty, D.S.; Rameswara Rao, A.; Hemantha Rao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderabad (India)

    2010-07-01

    In the PHWR fuel fabrication line resistance welding processes are used for joining various zirconium based alloy components to fuel tube of similar material. The quality requirement of these welding processes is very stringent and has to meet all the product requirements. At present these welding processes are being carried out by using standard resistance welding machines. In the resistance welding process in addition to current and time, force is one of the critical and important parameter, which influences the weld quality. At present advanced feed back type fast response medium frequency weld controllers are being used. This has upslope/down slope, constant and repetitive weld pattern selection features makes this critical welding process more reliable. Compared to weld controllers, squeeze force application devices are limited and normally standard high response pneumatic cylinders are used in the welding process. With this type of devices the force is constant during welding process and cannot be varied during welding process as per the material deformation characteristics. Similarly due to non-availability of feed back systems in the squeeze force application systems restricts the accuracy and quality of the welding process. In the present paper the influence of squeeze force pattern on the weld quality using advanced feed back type servo based force control system was studied. Different squeeze forces were used during pre and post weld heat periods along with constant force and compared with the weld quality. (author)

  5. John Leask Lumley: Whither Turbulence?

    Science.gov (United States)

    Leibovich, Sidney; Warhaft, Zellman

    2018-01-01

    John Lumley's contributions to the theory, modeling, and experiments on turbulent flows played a seminal role in the advancement of our understanding of this subject in the second half of the twentieth century. We discuss John's career and his personal style, including his love and deep knowledge of vintage wine and vintage cars. His intellectual contributions range from abstract theory to applied engineering. Here we discuss some of his major advances, focusing on second-order modeling, proper orthogonal decomposition, path-breaking experiments, research on geophysical turbulence, and important contributions to the understanding of drag reduction. John Lumley was also an influential teacher whose books and films have molded generations of students. These and other aspects of his professional career are described.

  6. Titular Tilting in John Ashbery

    DEFF Research Database (Denmark)

    Balle, Søren Hattesen

    2008-01-01

    Among the numerous poems published by the American poet John Ashbery since his debut in 1956 one finds a few that specifically deal with the issue of entitlement. These poems do not appear in one single of his volumes, but are disseminated throughout Ashbery’s career and production. Their occurre......Among the numerous poems published by the American poet John Ashbery since his debut in 1956 one finds a few that specifically deal with the issue of entitlement. These poems do not appear in one single of his volumes, but are disseminated throughout Ashbery’s career and production....... Their occurrence neither follows any particular plan, nor do they form part of a larger poetic or thematic whole in the volumes where they have been published. Rather, they are perhaps better characterized as “typically atypical of Ashbery’s poetry” – to put it in paradoxical terms used by John Shoptaw in his 1994...

  7. John Stuart Mill, John Rawls y Amartya Sen, los tres nombres de la equidad

    Directory of Open Access Journals (Sweden)

    María Teresa Lopera

    1997-07-01

    Full Text Available Tres autores como John Stuart Mill, John Rawls y Amartia Sen son objeto de análisis en este artículo que estudia el tema de la equidad en un contexto que se caracteriza por el abandono casi generalizado del estudio de los valores en relación a los grandes problemas económicos; el artículo defiende como necesaria la recuperación de las preocupaciones éticas en la ciencia económica. La segunda parte, presenta una bibliografía reciente presentada como respuesta a la obra de John Rawls a partir de 1985, cuando este autor da el llamado giro desde su teoría de la justicia como equidad hacia un reciente liberalismo político, período de gran interés para comprender las discusiones actuales de la filosofía política y el futuro de la discusión interdisciplinaria con la economía.

  8. Selecting sex: the effect of preferring sons.

    Science.gov (United States)

    Hesketh, Therese

    2011-11-01

    Son preference remains common in countries from East Asia through South Asia to the Middle East and North Africa. Where sex selective technology and abortion are readily available, such as in China, South Korea and India, this has led to a marked excess in male births. Worst excesses are seen in parts of rural China where there are 140 male births for every 100 female. This leads to large numbers of unmarriageable men. Concerns about the consequences centre around the propensity to aggression and violence of these men with increased levels of crime and antisocial behaviour, threatening societal stability and security. But recent studies do not support these assumptions, but rather suggest that these men are marginalised, lonely, withdrawn and prone to psychological problems. Measures to reduce sex selection should include enforcement of existing legislation on sex-selection, and public awareness campaigns about the dangers of late abortion and gender imbalance. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  9. L'astronomie et son histoire

    CERN Document Server

    Roy, Jean-René

    1982-01-01

    Le livre de Jean-René Roy nous présente une vaste synthèse des connaissances présentes en astronomie. Le grand mérite du livre est de dérouler son sujet en parallèle avec une histoire de l'astronomie. Le côté historique est ici beaucoup plus qu'un luxe. Il redonne leurs dimensions vraies aux réponses qu'apporte l'astronomie. Pour bien sentir la nature d'une étape franchie, il faut aussi avoir vécu la situation telle qu'elle se présentait avant. Et les fiches personnelles incluses dans le livre ont l'intérêt de nous rapprocher encore plus du "" feu de l'action "". Écrit dans un style direct et

  10. Lo que son mujeres en los escenarios

    Directory of Open Access Journals (Sweden)

    González Cañal, Rafael

    2007-06-01

    Full Text Available In this article I review the publishing and stage trajectory of one of Rojas Zorrilla’s most significant plays: Lo que son mujeres. As well as collecting a list of the different editions, I emphasize the 1822 version by the Mexican Manuel Eduardo de Gorostiza, which started a new renaissance period for this play on stage. I also analyze the 1899 one-act version by Emilio Bobadilla. Finally, I include all the different productions between the 17th and the 19th centuries, and address the little interest aroused in the 20th century–suffice to say that it has not been staged even during these early years of the 21st century when the centenary of Rojas Zorrilla is being celebrated.En este artículo se hace un repaso detallado de la fortuna editorial y escénica de una de las obras más significativas de Rojas Zorrilla: Lo que son mujeres. Aparte de recoger las diferentes ediciones de la misma, se hace hincapié en la refundición del mexicano Manuel Eduardo de Gorostiza, estrenada en 1822, que abrió un período de cierta recuperación de este texto dramático en los escenarios. Se analiza también la refundición que llevó a cabo en un solo acto Emilio Bobadilla en 1899. Finalmente, se registran todas las representaciones conocidas de la obra desde el siglo XVII hasta el siglo XIX y se constata el poco interés que ha despertado en los escenarios del siglo XX. Incluso en los últimos años, en los que los montajes de obras de Rojas comienzan a ser más frecuentes, esta obra no ha sido todavía llevada a escena.

  11. The Poetry of John Dewey

    Science.gov (United States)

    Williams, Jerry L.

    2016-01-01

    This essay examines the poetry of John Dewey, 101 poems in total. Characteristic of the rhymed and metered poetry of the period, they show a very human side of Dewey. This analysis argues that many of his poems deal with existential themes--love, finitude, and God, for example. On a deeper level these poems are also show connections to Dewey's…

  12. An Interview with John Liontas

    Science.gov (United States)

    Sadeghi, Karim

    2017-01-01

    John I. Liontas, Ph.D. is an associate professor of foreign languages, English for speakers of other languages (ESOL), and technology in education and second language acquisition (TESLA), and director and faculty of the TESLA doctoral program at the University of South Florida. Dr. Liontas is a distinguished thought leader, author, and…

  13. John Dewey, Gothic and Modern

    Science.gov (United States)

    Kaminsky, James S.

    2010-01-01

    It is argued here that understanding John Dewey's thought as that of a prodigal liberal or a fellow traveller does not capture the complexity of his work. It is also important to recognise the portion of his work that is "historie morale." In the very best sense it is epic, encapsulating the hopes and dreams of a history of the American people in…

  14. Rees, Prof. Lord Martin (John)

    Indian Academy of Sciences (India)

    Home; Fellowship. Fellow Profile. Elected: 1991 Honorary. Rees, Prof. Lord Martin (John) FRS. Date of birth: 23 June 1942. Address: Emeritus professor of Cosmology & Astrophysics, Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, U.K.. Contact: Office: (+44-1223) 33 7548

  15. The Art of John Biggers

    Science.gov (United States)

    Coy, Mary

    2010-01-01

    In their 2005 exhibit of John Biggers' work, the New Orleans Museum of Art described it as being inspired by "African art and culture, the injustices of a segregated United States, the stoic women in his own family, and the heroes of everyday survival." In this article, the author describes how her students reinterpreted Biggers' work.…

  16. Dr. John Marburger visits DESY

    CERN Multimedia

    2003-01-01

    Dr. John Marburger, Director of the United States Office of Science and Technology Policy, visited the research center DESY in Hamburg. The American physicist wanted to inform himself about the status of the TESLA X-ray laser and the TESLA linear collider as well as the international collaboration at DESY (1/2 page).

  17. Thomas, Prof. Sir John Meurig

    Indian Academy of Sciences (India)

    Thomas, Prof. Sir John Meurig FRS. Date of birth: 15 December 1932. Address: Department of Materials Science and, Metallurgy, New Museums Site, 27, Babbage ... Theory Of Evolution. Posted on 23 January 2018. Joint Statement by the Three Science Academies of India on the teaching of the theory of evolution more.

  18. John Dalton (1766–1844)

    Indian Academy of Sciences (India)

    IAS Admin

    of matter and the development of science in the world, especially in. Europe. During ... He belonged to a family of Quakers. (Society of ... During this period, Dalton came under the influence of John Gough, who suggested that he maintain a ...

  19. Model-based nonlinear control of hydraulic servo systems: Challenges, developments and perspectives

    Science.gov (United States)

    Yao, Jianyong

    2018-06-01

    Hydraulic servo system plays a significant role in industries, and usually acts as a core point in control and power transmission. Although linear theory-based control methods have been well established, advanced controller design methods for hydraulic servo system to achieve high performance is still an unending pursuit along with the development of modern industry. Essential nonlinearity is a unique feature and makes model-based nonlinear control more attractive, due to benefit from prior knowledge of the servo valve controlled hydraulic system. In this paper, a discussion for challenges in model-based nonlinear control, latest developments and brief perspectives of hydraulic servo systems are presented: Modelling uncertainty in hydraulic system is a major challenge, which includes parametric uncertainty and time-varying disturbance; some specific requirements also arise ad hoc difficulties such as nonlinear friction during low velocity tracking, severe disturbance, periodic disturbance, etc.; to handle various challenges, nonlinear solutions including parameter adaptation, nonlinear robust control, state and disturbance observation, backstepping design and so on, are proposed and integrated, theoretical analysis and lots of applications reveal their powerful capability to solve pertinent problems; and at the end, some perspectives and associated research topics (measurement noise, constraints, inner valve dynamics, input nonlinearity, etc.) in nonlinear hydraulic servo control are briefly explored and discussed.

  20. A New Servo Control Drive for Electro Discharge Texturing System Industrial Applications Using Ultrasonic Technology

    Directory of Open Access Journals (Sweden)

    M. Shafik

    2013-07-01

    Full Text Available This paper presents a new ultrasonic servo control drive for electro discharge texturing system industrial applications. The new drive is aiming to overcome the current teething issues of the existing electro discharge texturing system, servo control drive level of precision, processing stability, dynamic response and surface profile of the machined products. The new ultrasonic servo control drive consists of three main apparatuses, an ultrasonic motor, electronic driver and control unit. The ultrasonic motor consists of three main parts, the stator, rotor and sliding element. The motor design process, basic configuration, principles of motion, finite element analysis and experimental examination of the main characteristics is discussed in this paper. The electronic driver of the motor consists of two main stages which are the booster and piezoelectric amplifier. The experimental test and validation of the developed servo control drive in electro discharge texturing platform is also discussed and presented in this paper. The initial results showed that the ultrasonic servo control drive is able to provide: a bidirectional of motion, a resolution of <50μm and a dynamic response of <10msec. The electron microscopic micro examination into the textured samples showed that: a clear improvement in machining stability, products surface profile, a notable reduction in the processing time, arcing and short-circuiting teething phenomena.

  1. Researching on YH100 Numerical Control Servo Press Hydraulic Control System and Control Algorithm

    Directory of Open Access Journals (Sweden)

    Kai LI

    2014-09-01

    Full Text Available In order to study the numerical control (NC servo press hydraulic control system and its control algorithm. The numerical control servo press performance and control principle of hydraulic control system are analyzed. According to the flow equation of the hydraulic control valve, hydraulic cylinder flow continuity equation and the force balance equation of the hydraulic cylinder with load press, the mathematical model of hydraulic control system is established. And the servo press hydraulic system transfer function is deduced. Introducing the suitable immune particle swarm control algorithm for servo press hydraulic system, and the control system block diagram is established. Immune algorithm is used to optimize new control parameters of the system and adopt the new optimization results to optimize the system simulation. The simulation result shows that the hydraulic system’s transition time controlled by the immune particle swarm algorithm is shorter than traditional ones, and the control performance is obviously improved. Finally it can be concluded that immune particle swarm PID control have these characteristics such as quickness, stability and accuracy. Applying this principle into application, the obtained YH100 numerical control servo press hydraulic control system meets the requirement.

  2. Sons fricativos surdos Voiceless fricatives sounds

    Directory of Open Access Journals (Sweden)

    Carla Aparecida Cielo

    2008-01-01

    Full Text Available TEMA: características dos sons fricativos surdos. OBJETIVO: propor uma revisão da literatura pertinente às características acústicas, fonéticas e fonológicas dos fonemas fricativos surdos que integram o sistema fonológico do Português. Além disso, são descritas suas aplicações na terapia vocal. CONCLUSÕES: os fricativos são fonemas agudos, abrangendo de 2500 a 8000Hz; são plenamente adquiridos até os 3:7 anos de idade; o /s/ que também é o mais afetado em casos de frênulo lingual curto; a omissão do /s/ é uma das ocorrências mais freqüentes na alfabetização; sendo que, no desvio fonológico e na fissura lábio-palatina, freqüentemente ocorre comprometimento de toda a classe de fricativos. Na avaliação de voz, os fricativos são mencionados com as medidas de TMF e relação s/z, bem como seu uso como sons de apoio na fonoterapia.BACKGROUND: characteristics of voiceless fricative sounds PURPOSE: to review the literature related to acoustic, phonetics and phonological characteristics of voiceless fricative sounds that are part of the phonological system of the Portuguese Language. Furthermore, it describes the use of these sounds in voice therapy. CONCLUSIONS: fricatives are acute phonemes comprised between 2500 and 8000 Hz; they are fully acquired up to the age of 3:7 years; the /s/, which is the most affected in cases of short lingual frenum; omission of the /s/ is one of the most frequent occurrences during literacy education; and in the phonological deviation and labial-palatine fissure the entire class of fricatives is frequently affected. In voice assessment, fricative sounds are mentioned as TMF measurements and s/z relationship, and their use as support sounds in speech therapy.

  3. Foreword: Sir John Pendry FRS Sir John Pendry FRS

    Science.gov (United States)

    Inglesfield, John; Echenique, Pedro

    2008-07-01

    John Pendry John Inglesfield and Pedro Echenique write: John Pendry's 65th birthday is on 4 July 2008, and this issue of the Journal of Physics: Condensed Matter is dedicated to him, with articles by friends, colleagues, and former students. By any standards, John Pendry is a great scientist, who has made—and continues to make—an enormous contribution to physics; the wide range of his interests is reflected in the scope of these articles. Not many scientists can establish a completely new and unexpected area of research, but this has been John's achievement in the last few years in the field of metamaterials, materials whose electromagnetic properties depend on their structure rather than the materials of which the structure is built. In this way, structures with effectively negative electrical permittivity and negative magnetic permeability can be constructed, demonstrating negative refraction; through metamaterials scientists now have access to properties not found in nature, and never previously explored experimentally. Never a week goes by without a potential new application of metamaterials, whether it is perfect lensing, or the cloak of invisibility. This has certainly led to tremendous visibility for John himself, with guest lectures all over the world, and radio and television appearances. John Pendry's first paper was published exactly 40 years ago, 'Analytic properties of pseudopotentials' [1], and since then he has published 310 articles at the latest count. But this first paper already reflected something of the way John works. His PhD project, with Volker Heine at the Cavendish Laboratory, was to interpret the scattering of low energy electrons from surfaces, the technique of LEED which was to become the method of choice for determining surface structure. Although the energy of the electrons in LEED is relatively low—say 50 eV—it is much higher than the energy of the conduction electrons, for which pseudopotentials had been devised, and John

  4. Dombey and Son: An Inverted Maid's Tragedy

    Directory of Open Access Journals (Sweden)

    Taher Badinjki

    2015-06-01

    Full Text Available Ross Dabney, J. Butt & K. Tillotson, and others think that Dickens revised the role of Edith in the original plan of Dombey and Son upon the advice of a friend. I tend to believe that Dickens's swerve from his course was prompted by two motives, his relish for grand scenes, and his endeavour to engage the reader's sympathies for a character who was a victim of a social practice which he was trying to condemn. Dickens's humanitarian attitude sought to redeem the sinner and condemn the sin. In engaging the reader's sympathies,  Dickens  had entrapped his own.  Both Edith and Alice are shown as victims of rapacious mothers who sell anything, or anybody for money. While Good Mrs Brown sells Alice's virtue and innocence for cash, Mrs Skewton trades on Edith's beauty in the marriage market to secure fortune and a good establishment. Edith and Alice's maturity and moral growth and their scorn and anger at their mothers' false teaching come in line with public prudery. Moreover, their educators in the principles of Mammonism have not succeeded altogether in stifling their innate feminine tenderness and capacity for affection, the thing that draws them near their reader's heart and wins them love and sympathy. Keywords: Money,  transaction,  victims,  saleable,  Mormonism,  greedy, rapacious

  5. Mate-sampling costs and sexy sons.

    Science.gov (United States)

    Kokko, H; Booksmythe, I; Jennions, M D

    2015-01-01

    Costly female mating preferences for purely Fisherian male traits (i.e. sexual ornaments that are genetically uncorrelated with inherent viability) are not expected to persist at equilibrium. The indirect benefit of producing 'sexy sons' (Fisher process) disappears: in some models, the male trait becomes fixed; in others, a range of male trait values persist, but a larger trait confers no net fitness advantage because it lowers survival. Insufficient indirect selection to counter the direct cost of producing fewer offspring means that preferences are lost. The only well-cited exception assumes biased mutation on male traits. The above findings generally assume constant direct selection against female preferences (i.e. fixed costs). We show that if mate-sampling costs are instead derived based on an explicit account of how females acquire mates, an initially costly mating preference can coevolve with a male trait so that both persist in the presence or absence of biased mutation. Our models predict that empirically detecting selection at equilibrium will be difficult, even if selection was responsible for the location of the current equilibrium. In general, it appears useful to integrate mate sampling theory with models of genetic consequences of mating preferences: being explicit about the process by which individuals select mates can alter equilibria. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  6. Robustness-tracking control based on sliding mode and H∞ theory for linear servo system

    Institute of Scientific and Technical Information of China (English)

    TIAN Yan-feng; GUO Qing-ding

    2005-01-01

    A robustness-tracking control scheme based on combining H∞ robust control and sliding mode control is proposed for a direct drive AC permanent-magnet linear motor servo system to solve the conflict between tracking and robustness of the linear servo system. The sliding mode tracking controller is designed to ensure the system has a fast tracking characteristic to the command, and the H∞ robustness controller suppresses the disturbances well within the close loop( including the load and the end effect force of linear motor etc. ) and effectively minimizes the chattering of sliding mode control which influences the steady state performance of the system. Simulation results show that this control scheme enhances the track-command-ability and the robustness of the linear servo system, and in addition, it has a strong robustness to parameter variations and resistance disturbances.

  7. Analysis of the jet pipe electro-hydraulic servo valve with finite element methods

    Directory of Open Access Journals (Sweden)

    Kaiyu Zhao

    2018-01-01

    Full Text Available The dynamic characteristics analysis about the jet pipe electro-hydraulic servo valve based on experience and mathematical derivation was difficult and not so precise. So we have analysed the armature feedback components, torque motor and jet pipe receiver in electrohydraulic servo valve by sophisticated finite element analysis tools respectively and have got physical meaning data on these parts. Then the data were fitted by Matlab and the mathematical relationships among them were calculated. We have done the dynamic multi-physical fields’ Simulink co-simulation using above mathematical relationship, and have got the input-output relationship of the overall valve, the frequency response and step response. This work can show the actual working condition accurately. At the same time, we have considered the materials and the impact of the critical design dimensions in the finite element analysis process. It provides some new ideas to the overall design of jet pipe electro-hydraulic servo valve.

  8. Fault Diagnosis of Hydraulic Servo Valve Based on Genetic Optimization RBF-BP Neural Network

    Directory of Open Access Journals (Sweden)

    Li-Ping FAN

    2014-04-01

    Full Text Available Electro-hydraulic servo valves are core components of the hydraulic servo system of rolling mills. It is necessary to adopt an effective fault diagnosis method to keep the hydraulic servo valve in a good work state. In this paper, RBF and BP neural network are integrated effectively to build a double hidden layers RBF-BP neural network for fault diagnosis. In the process of training the neural network, genetic algorithm (GA is used to initialize and optimize the connection weights and thresholds of the network. Several typical fault states are detected by the constructed GA-optimized fault diagnosis scheme. Simulation results shown that the proposed fault diagnosis scheme can give satisfactory effect.

  9. Robust Hinfinity position control synthesis of an electro-hydraulic servo system.

    Science.gov (United States)

    Milić, Vladimir; Situm, Zeljko; Essert, Mario

    2010-10-01

    This paper focuses on the use of the techniques based on linear matrix inequalities for robust H(infinity) position control synthesis of an electro-hydraulic servo system. A nonlinear dynamic model of the hydraulic cylindrical actuator with a proportional valve has been developed. For the purpose of the feedback control an uncertain linearized mathematical model of the system has been derived. The structured (parametric) perturbations in the electro-hydraulic coefficients are taken into account. H(infinity) controller extended with an integral action is proposed. To estimate internal states of the electro-hydraulic servo system an observer is designed. Developed control algorithms have been tested experimentally in the laboratory model of an electro-hydraulic servo system. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

  10. An electro-hydraulic servo control system research for CFETR blanket RH

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Changqi [Hefei University of Technology, Hefei 230009, Anhui (China); Tang, Hongjun, E-mail: taurustang@126.com [Hefei University of Technology, Hefei 230009, Anhui (China); Qi, Songsong [Hefei University of Technology, Hefei 230009, Anhui (China); Cheng, Yong; Feng, Hansheng; Peng, Xuebing; Song, Yuntao [Institute of Plasma Physics Chinese Academy of Sciences, Hefei 230031, Anhui (China)

    2014-11-15

    Highlights: • We discussed the conceptual design of CFETR blanket RH maintenance system. • The mathematical model of electro-hydraulic servo system was calculated. • A fuzzy adaptive PD controller was designed based on control theory and experience. • The co-simulation models of the system were established with AMESim/Simulink. • The fuzzy adaptive PD algorithm was designed as the core strategy of the system. - Abstract: Based on the technical design requirements of China Fusion Engineering Test Reactor (CFETR) blanket remote handling (RH) maintenance, this paper focus on the control method of achieving high synchronization accuracy of electro-hydraulic servo system. Based on fuzzy control theory and practical experience, a fuzzy adaptive proportional-derivative (PD) controller was designed. Then a more precise co-simulation model was established with AMESim/Simulink. Through the analysis of simulation results, a fuzzy adaptive PD control algorithm was designed as the core strategy of electro-hydraulic servo control system.

  11. Research Based on AMESim of Electro-hydraulic Servo Loading System

    Science.gov (United States)

    Li, Jinlong; Hu, Zhiyong

    2017-09-01

    Electro-hydraulic servo loading system is a subject studied by many scholars in the field of simulation and control at home and abroad. The electro-hydraulic servo loading system is a loading device simulation of stress objects by aerodynamic moment and other force in the process of movement, its function is all kinds of gas in the lab condition to analyze stress under dynamic load of objects. The purpose of this paper is the design of AMESim electro-hydraulic servo system, PID control technology is used to configure the parameters of the control system, complete the loading process under different conditions, the optimal design parameters, optimization of dynamic performance of the loading system.

  12. An electro-hydraulic servo control system research for CFETR blanket RH

    International Nuclear Information System (INIS)

    Chen, Changqi; Tang, Hongjun; Qi, Songsong; Cheng, Yong; Feng, Hansheng; Peng, Xuebing; Song, Yuntao

    2014-01-01

    Highlights: • We discussed the conceptual design of CFETR blanket RH maintenance system. • The mathematical model of electro-hydraulic servo system was calculated. • A fuzzy adaptive PD controller was designed based on control theory and experience. • The co-simulation models of the system were established with AMESim/Simulink. • The fuzzy adaptive PD algorithm was designed as the core strategy of the system. - Abstract: Based on the technical design requirements of China Fusion Engineering Test Reactor (CFETR) blanket remote handling (RH) maintenance, this paper focus on the control method of achieving high synchronization accuracy of electro-hydraulic servo system. Based on fuzzy control theory and practical experience, a fuzzy adaptive proportional-derivative (PD) controller was designed. Then a more precise co-simulation model was established with AMESim/Simulink. Through the analysis of simulation results, a fuzzy adaptive PD control algorithm was designed as the core strategy of electro-hydraulic servo control system

  13. Servo-control of water and sodium homeostasis during renal clearance measurements in conscious rats

    DEFF Research Database (Denmark)

    Thomsen, Klaus; Shirley, David G

    2007-01-01

    Servo-controlled fluid and sodium replacement during clearance studies is used in order to prevent loss of body fluid and sodium following diuretic/natriuretic procedures. However, even under control conditions, the use of this technique is sometimes associated with increases in proximal tubular...... fluid output (assessed by lithium clearance) and excretion rates. The present study examined the reason for these increases. The first series of experiments showed that one cause is volume overloading. This can occur if the servo system is activated from the start, i.e., during the establishment...... not seen when blood samples are replaced with the animal's own red blood cells resuspended in isotonic saline. When these pitfalls are avoided, servo-controlled sodium and fluid replacement is a reliable technique that makes it possible to study the effects of natriuretic and/or diuretic stimuli without...

  14. Research on Visual Servo Grasping of Household Objects for Nonholonomic Mobile Manipulator

    Directory of Open Access Journals (Sweden)

    Huangsheng Xie

    2014-01-01

    Full Text Available This paper focuses on the problem of visual servo grasping of household objects for nonholonomic mobile manipulator. Firstly, a new kind of artificial object mark based on QR (Quick Response Code is designed, which can be affixed to the surface of household objects. Secondly, after summarizing the vision-based autonomous mobile manipulation system as a generalized manipulator, the generalized manipulator’s kinematic model is established, the analytical inverse kinematic solutions of the generalized manipulator are acquired, and a novel active vision based camera calibration method is proposed to determine the hand-eye relationship. Finally, a visual servo switching control law is designed to control the service robot to finish object grasping operation. Experimental results show that QR Code-based artificial object mark can overcome the difficulties brought by household objects’ variety and operation complexity, and the proposed visual servo scheme makes it possible for service robot to grasp and deliver objects efficiently.

  15. Analogical study of the servo-control of a reactivity modulator

    International Nuclear Information System (INIS)

    Le Bot, Michel

    1969-03-01

    In the context of the study of the transfer functions related to the Cabri reactor, this paper presents: the objective of the servo-control (reactivity modulator, reasons for the analogical study), the principles of the servo-control (description of the servo-controlled system, elaboration of the error signal, principles of the phase meter, critical analysis of different types of phase meters), the analogical formulation (transfer diagram of the process, analogical simulation of the process, analogical realization of the phase meter, simulation of the Low Frequency generator), study of the controlled system and results (system responses to echelon and ramp signals, responses of the controlled system with the phase meter in feedback)

  16. The performance and limitations of FPGA-based digital servos for atomic, molecular, and optical physics experiments.

    Science.gov (United States)

    Yu, Shi Jing; Fajeau, Emma; Liu, Lin Qiao; Jones, David J; Madison, Kirk W

    2018-02-01

    In this work, we address the advantages, limitations, and technical subtleties of employing field programmable gate array (FPGA)-based digital servos for high-bandwidth feedback control of lasers in atomic, molecular, and optical physics experiments. Specifically, we provide the results of benchmark performance tests in experimental setups including noise, bandwidth, and dynamic range for two digital servos built with low and mid-range priced FPGA development platforms. The digital servo results are compared to results obtained from a commercially available state-of-the-art analog servo using the same plant for control (intensity stabilization). The digital servos have feedback bandwidths of 2.5 MHz, limited by the total signal latency, and we demonstrate improvements beyond the transfer function offered by the analog servo including a three-pole filter and a two-pole filter with phase compensation to suppress resonances. We also discuss limitations of our FPGA-servo implementation and general considerations when designing and using digital servos.

  17. Disturbance observer that uses radial basis function networks for the low speed control of a servo motor

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Bae, C.H.; Blaabjerg, Frede

    2005-01-01

    A scheme to estimate the moment of inertia in a servo motor drive system at very low speed is proposed. The typical speed estimation scheme used in most servo systems operated at low speed is highly sensitive to variations in the moment of inertia. An observer that uses a radial basis function...

  18. The performance and limitations of FPGA-based digital servos for atomic, molecular, and optical physics experiments

    Science.gov (United States)

    Yu, Shi Jing; Fajeau, Emma; Liu, Lin Qiao; Jones, David J.; Madison, Kirk W.

    2018-02-01

    In this work, we address the advantages, limitations, and technical subtleties of employing field programmable gate array (FPGA)-based digital servos for high-bandwidth feedback control of lasers in atomic, molecular, and optical physics experiments. Specifically, we provide the results of benchmark performance tests in experimental setups including noise, bandwidth, and dynamic range for two digital servos built with low and mid-range priced FPGA development platforms. The digital servo results are compared to results obtained from a commercially available state-of-the-art analog servo using the same plant for control (intensity stabilization). The digital servos have feedback bandwidths of 2.5 MHz, limited by the total signal latency, and we demonstrate improvements beyond the transfer function offered by the analog servo including a three-pole filter and a two-pole filter with phase compensation to suppress resonances. We also discuss limitations of our FPGA-servo implementation and general considerations when designing and using digital servos.

  19. John Adams and his times

    International Nuclear Information System (INIS)

    Amaldi, E.

    1986-01-01

    In this first John Adams' Memorial Lecture, an outline is given of his work, especially from the beginning of CERN in 1952 until his death in 1984. The historical survey covers John Adams' technical and managerial contributions to the development of CERN and its accelerators, as well as to fusion research in Britain and Europe. Exemplified by his role as member and president of the International Committee for Future Accelerators (ICFA), Adams' interest in international co-operation is also stressed. In the spirit of this great European, arguments are given for CERN to continue to be the first-rate high-energy physics laboratory which it has been in the past. (orig.)

  20. John von Neumann selected letters

    CERN Document Server

    2005-01-01

    John von Neuman was perhaps the most influential mathematician of the twentieth century, especially if his broad influence outside mathematics is included. Not only did he contribute to almost all branches of mathematics and created new fields, but he also changed post-World War II history with his work on the design of computers and with being a sought-after technical advisor to many figures in the U.S. military-political establishment in the 1940s and 1950s. The present volume is the first substantial collection of (previously mainly unpublished) letters written by von Neumann to colleagues, friends, government officials, and others. The letters give us a glimpse of the thinking of John von Neumann about mathematics, physics, computer science, science management, education, consulting, politics, and war. Readers of quite diverse backgrounds will find much of interest in this fascinating first-hand look at one of the towering figures of twentieth century science.

  1. Son Preference and Its Consequences (A Review) | Shah | Gender ...

    African Journals Online (AJOL)

    Cultural preference for sons was evident from that fact that in Hindu\\'s traditions, ... A common perception of son\\'s preference on daughter was the ascribed ability of ... against females in the allocation of food and health care within the household. ... their-self in most of the south Asian countries preferred sons to daughters.

  2. Is John Locke a democrat?

    DEFF Research Database (Denmark)

    Svensson, Palle

      Over recent years there has been a tendency to present John Locke as an equalitarian democrat (Ashcraft) and being close to the political views of the levellers (Waldron). This is not a completely new interpretation (Kendall, 1941), but contrasts with the prevalent view presented in textbooks (......, criteria for a democratic process, and the institutions of polyarchy. The conclusion has implications for the relationship between political liberalism and constitutionalism on the one hand and democracy on the other....

  3. Charles Darwin and John Herschel

    Science.gov (United States)

    Warner, B.

    2009-11-01

    The influence of John Herschel on the philosophical thoughts of Charles Darwin, both through the former's book, Natural Philosophy, and through their meeting in 1836 at the Cape of Good Hope, is discussed. With Herschel having himself speculated on evolution just a few months before he met Darwin, it is probable that he stimulated at least the beginnings of the latter's lifelong work on the subject.

  4. A Conversation with John Nelder

    OpenAIRE

    Senn, Stephen

    2003-01-01

    John Ashworth Nelder was born in 1924 in Dulverton, Somerset, England. He received his secondary education in nearby Tiverton at Blundell's, a "public" [that is to say, privately funded] school that he attended as a day pupil. In 1942, he entered Sidney Sussex College, Cambridge University, to read mathematics. His studies were interrupted after one year by war service and he trained as an RAF navigator in South Africa. He returned to Cambridge in 1946 and complete his studies, graduating a "...

  5. John Glenn Biomedical Engineering Consortium

    Science.gov (United States)

    Nall, Marsha

    2004-01-01

    The John Glenn Biomedical Engineering Consortium is an inter-institutional research and technology development, beginning with ten projects in FY02 that are aimed at applying GRC expertise in fluid physics and sensor development with local biomedical expertise to mitigate the risks of space flight on the health, safety, and performance of astronauts. It is anticipated that several new technologies will be developed that are applicable to both medical needs in space and on earth.

  6. Caruso St John y Robert Smithson: Interferencias

    Directory of Open Access Journals (Sweden)

    Emilia Hernández Pezzi

    2016-05-01

    Full Text Available Resumen Los discursos cruzados son el soporte común del presente número de Cuadernos. El cruce que planteamos tiene como protagonistas al artista Robert Smithson y a los arquitectos Adam Caruso y Peter St John. Estos últimos hacen mención del trabajo del artista norteamericano para explicar su proyecto de remodelación de Stortorget, la plaza de la catedral en el centro de Kalmar, Suecia. A partir de aquí, comenzamos una exploración del trabajo y las preocupaciones de ambos que nos permite dibujar convergencias y sintonías procesuales por encima de las diferencias temáticas, ideológicas y estilísticas. Al disponer en paralelo la obra de Smithson y Caruso St John descubrimos vibraciones y resonancias que muestran una interacción productiva de sus preocupaciones. La materia se convierte en sus propuestas en un objeto activo y sensible, un depósito energético con el que operar. El traslado de piedras en Stortorget convoca la memoria de la ciudad del mismo modo que el basalto y la sal del Spiral Jetty, erosionados por el tiempo, nos hablan de procesos abiertos. El tiempo y la memoria pasan a ser soportes estratégicos con los que construyen sus miradas. Los objetos se disuelven en las relaciones que establecen con su entorno produciendo equilibrios frágiles e instantáneos. De esta manera el artículo pretende generar un vórtice de reflexión, una espiral en cuyo recorrido se manifiesten las tensiones parciales del cruce propuesto, sus fijezas momentáneas.

  7. John Strong - 1941-2006

    CERN Multimedia

    2006-01-01

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on 31 July, a few days before his 65th birthday. John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers. He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such h...

  8. Obituary: John Daniel Kraus, 1910-2004

    Science.gov (United States)

    Kraus, John D., Jr.; Marhefka, Ronald J.

    2005-12-01

    , 1992, 1999) and "Radio Astronomy" (McGraw-Hill: 1966; Cygnus-Quasar: 1986). They have appeared in Chinese, Japanese, Korean, Spanish, Russian, and Portuguese. He also wrote popular books, including the autobiographical "Big Ear" and "Big Ear Two" (Cygnus-Quasar: 1976, 1995), and the instructional "Our Cosmic Universe" (Cygnus-Quasar: 1980). His professional memberships included the American Astronomical Society, election to the National Academy of Engineering (1972), and Fellow of the Institute of Electrical and Electronic Engineers. He received the Centennial Medal (1984), the Edison Medal (1985), and the Heinrich Hertz Medal (1990) from the IEEE. The Antenna and Propagation Society of IEEE twice awarded him its Distinguished Achievement Award, the last in 2003. He was awarded the Sullivant Medal (1970) from the Ohio State University and the Outstanding Achievement Award (1981) from the University of Michigan. John and his wife, Alice Nelson Kraus, whom he married in 1941, were committed environmentalists. Alice and he donated the 80-acre Kraus Wilderness Preserve to the Ohio Wesleyan University in 1976. They also endowed scholarships to enhance environmental learning for students at Ohio Wesleyan and OSU. In addition, John was a passionate advocate of metrification in the USA. Predeceased in 2002 by his beloved wife, he is survived by two sons, John D. Kraus, Jr., and Nelson H. Kraus, and five grandchildren. His professional and personal papers are housed at the National Radio Astronomy Observatory archives in Charlottesville, Virginia. John was viewed by many as a last living link to many of the astonishing scientific discoveries of the 20th century. He valued an open mind and direct physical insights and was of a by-gone era of hands-on invention, empirical testing, and observational research. Yet, he commanded an insightful grasp of the theory, which he could translate into thought provoking learning experiences for students and working engineers alike. In his

  9. DC motors and servo-motors controlled by Raspberry Pi 2B

    Directory of Open Access Journals (Sweden)

    Šustek Michal

    2017-01-01

    Full Text Available The expanding capabilities of today’s microcontrollers and other devices lead to an increased utilization of these technologies in diverse fields. The automation and issue of remote control of moving objects belong to these fields. In this project, a microcontroller Raspberry Pi 2B was chosen for controlling DC motors and servo-motors. This paper provides basic insight into issue of controlling DC motors and servo-motors, connection between Raspberry and other components on breadboard and programming syntaxes for controlling motors in Python programming language.

  10. Active stabilization of a rapidly chirped laser by an optoelectronic digital servo-loop control.

    Science.gov (United States)

    Gorju, G; Jucha, A; Jain, A; Crozatier, V; Lorgeré, I; Le Gouët, J-L; Bretenaker, F; Colice, M

    2007-03-01

    We propose and demonstrate a novel active stabilization scheme for wide and fast frequency chirps. The system measures the laser instantaneous frequency deviation from a perfectly linear chirp, thanks to a digital phase detection process, and provides an error signal that is used to servo-loop control the chirped laser. This way, the frequency errors affecting a laser scan over 10 GHz on the millisecond timescale are drastically reduced below 100 kHz. This active optoelectronic digital servo-loop control opens new and interesting perspectives in fields where rapidly chirped lasers are crucial.

  11. Application of prediction of equilibrium to servo-controlled calorimetry measurements

    International Nuclear Information System (INIS)

    Mayer, R.L. II

    1987-01-01

    Research was performed to develop an endpoint prediction algorithm for use with calorimeters operating in the digital servo-controlled mode. The purpose of this work was to reduce calorimetry measurement times while maintaining the high degree of precision and low bias expected from calorimetry measurements. Data from routine operation of two calorimeters were used to test predictive models at each stage of development against time savings, precision, and robustness criteria. The results of the study indicated that calorimetry measurement times can be significantly reduced using this technique. The time savings is, however, dependent on parameters in the digital servo-control algorithm and on packaging characteristics of measured items

  12. Robust and Stable Disturbance Observer of Servo System for Low-Speed Operation

    DEFF Research Database (Denmark)

    Lee, Kyo Beum; Blaabjerg, Frede

    2007-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low-speed operation is sensitive to the variation of machine parameter, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable...

  13. Performance Improvement of Servo Machine Low Speed Operation Using RBFN Disturbance Observer

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2004-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The typical speed estimation scheme in most servo system for low speed operation is sensitive to the variation of machine parameters, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Networks (RBFN) is applied. The effectiveness of the proposed inertia estimation method is verified by experiments. It is concluded that the speed control performance in the low speed region is improved with the proposed...

  14. Concurrent image-based visual servoing with adaptive zooming for non-cooperative rendezvous maneuvers

    Science.gov (United States)

    Pomares, Jorge; Felicetti, Leonard; Pérez, Javier; Emami, M. Reza

    2018-02-01

    An image-based servo controller for the guidance of a spacecraft during non-cooperative rendezvous is presented in this paper. The controller directly utilizes the visual features from image frames of a target spacecraft for computing both attitude and orbital maneuvers concurrently. The utilization of adaptive optics, such as zooming cameras, is also addressed through developing an invariant-image servo controller. The controller allows for performing rendezvous maneuvers independently from the adjustments of the camera focal length, improving the performance and versatility of maneuvers. The stability of the proposed control scheme is proven analytically in the invariant space, and its viability is explored through numerical simulations.

  15. Parametric model of servo-hydraulic actuator coupled with a nonlinear system: Experimental validation

    Science.gov (United States)

    Maghareh, Amin; Silva, Christian E.; Dyke, Shirley J.

    2018-05-01

    Hydraulic actuators play a key role in experimental structural dynamics. In a previous study, a physics-based model for a servo-hydraulic actuator coupled with a nonlinear physical system was developed. Later, this dynamical model was transformed into controllable canonical form for position tracking control purposes. For this study, a nonlinear device is designed and fabricated to exhibit various nonlinear force-displacement profiles depending on the initial condition and the type of materials used as replaceable coupons. Using this nonlinear system, the controllable canonical dynamical model is experimentally validated for a servo-hydraulic actuator coupled with a nonlinear physical system.

  16. Aditivos alimentarios: ¿qué son, cómo actúan, por qué son tan necesarios?

    OpenAIRE

    Blanco de Alvarado-Ortiz, Teresa

    2014-01-01

    Para John M. deMan, en su obra PrincipIes of Food Chemistry a los aditivos alimentarios con frecuencia se les asocia a algo químico, otorgándose erradamente a lo quimico características de artificial, no siempre bueno para la salud.Dicen bien erradamente, porque hombres, animales, plantas, microorganismos, alimentos, aire, cerros, minas y todo lo que nos rodea en la maravillosa naturaleza, es químico. Los aditivos alimentarios,todos químicos, naturales o artificiales son extraordinarias susta...

  17. Having a Son Promotes Clean Cooking Fuel Use in Urban India: Women's Status and Son Preference

    OpenAIRE

    Avinash Kishore; Dean Spears

    2014-01-01

    Urban Indian households with a male first child are approximately 2 percentage points more likely to use clean cooking fuel than comparable households with a female first child. Given Indian son preference, there are at least two mechanisms by which child sex could affect fuel choice: by improving the intrahousehold status of women, who bear more of the costs of traditional fuels, or by presenting an opportunity to invest in children's health, in the context of a preference for healthier boys...

  18. John W. Daly - An Appreciation

    Science.gov (United States)

    Kirk, Kenneth L.

    2015-01-01

    John W. Daly was engaged in groundbreaking basic research for nearly 50 years at NIH in Bethesda, Maryland. A primary focus of his research included the discovery, structure elucidation, synthesis and pharmacology of alkaloids and other biologically active natural products. However, he earned further acclaim in other areas that included the investigation of the structure-activity relationships for agonists/antagonists at adenosine, adrenergic, histamine, serotonin, and acetylcholine receptors. In addition he was a pioneer in studies of the modulation and functional relationships for systems involving calcium, cyclic nucleotides, ion channels and phospholipids and in the mechanism of actions of caffeine and other xanthines. PMID:26160996

  19. A tribute to John Gibbon.

    Science.gov (United States)

    Church, Russell M.

    2002-04-28

    This article provides an overview of the published research of John Gibbon. It describes his experimental research on scalar timing and his development of scalar timing theory. It also describes his methods of research which included mathematical analysis, conditioning methods, psychophysical methods and secondary data analysis. Finally, it describes his application of scalar timing theory to avoidance and punishment, autoshaping, temporal perception and timed behavior, foraging, circadian rhythms, human timing, and the effect of drugs on timed perception and timed performance of Parkinson's patients. The research of Gibbon has shown the essential role of timing in perception, classical conditioning, instrumental learning, behavior in natural environments and in neuropsychology.

  20. John Donne no Brasil John Donne no Brasil

    Directory of Open Access Journals (Sweden)

    Jose Garcez Ghirardi

    2008-04-01

    Full Text Available O leitor fica sem saber a troco do que John Donne lhe surge de repente, num virar de página, e através de períodos que parecem responder a uma pergunta que não foi formulada.(... Ninguém, nem o Sr. Afrânio Coutinho falara, até então, de John Donne,(.... Simplesmente, esse trecho, como inúmeros outros (quase todos do livro, revela que leituras apaixonantes obrigaram o professor Afrânio Coutinho a tomar em seu caderno alguns apontamentos eruditos. (MARTINS 1983 vol.I: 621 A citação acima, extraída de um artigo de Wilson Martins (in O Estado de São Paulo, 25/02/54, ilustra bem a posição reservada a John Donne, até então, por aqueles que, no Brasil, se dedicavam aos estudos de literatura. “A troco do que” - perguntava o autor - deveria ser o leitor de Correntes Cruzadas confrontado com o nome de Donne? Quem, até aquele momento, dele se ocupara? Ninguém, respondia o erudito articulista (nem mesmo o Sr. Afrânio Coutinho, embora reconhecendo que o nome do poeta pudesse ter sido fonte de algumas “leituras apaixonantes” . Interessava-lhe apontar enfaticamente, porém, que a lembrança de Donne surgia de maneira gratuita, desligada de qualquer argumentação ou contexto que a preparas se ou justificasse. Não apenas Afrânio Coutinho silenciara sobre a obra de Donne em seu livro; ninguém, de fato, havia, até aquele momento, dedicado, ao poeta, qualquer atenção mais demorada. Curiosamente, o próprio artigo, assim como o livro nele discutido, atestava, no entanto, que o esquecimento do nome de Donne estava por findar.

  1. John Strong 1941-2006

    CERN Multimedia

    2006-01-01

    John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon Cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers.  He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such has been the lasting impact of these measurements that the paper on the pion form-factor had been cited 323 times up to the time of J...

  2. John Greenleaf's life of science.

    Science.gov (United States)

    Watenpaugh, Donald E

    2012-12-01

    This article summarizes the life and career of John E. Greenleaf, PhD. It complements an interview of Dr. Greenleaf sponsored by the American Physiological Society Living History Project found on the American Physiological Society website. Dr. Greenleaf is a "thought leader" and internationally renowned physiologist, with extensive contributions in human systems-level environmental physiology. He avoided self-aggrandizement and believed that deeds rather than words define one's legacy. Viewed another way, however, Greenleaf's words define his deeds: 48% of his 185 articles are first author works, which is an unusually high proportion for a scientist of his stature. He found that writing a thorough and thoughtful discussion section often led to novel ideas that drove future research. Beyond Greenleaf's words are the many students, postdocs, and collaborators lucky enough to have worked with him and thus learn and carry on his ways of science. His core principles included the following: avoid research "fads," embrace diversity, be the first subject in your own research, adhere to rules of fiscal responsibility, and respect administrative forces-but never back down from them when you know you are right. Greenleaf's integrity ensured he was usually right. He thrived on the axiom of many successful scientists: avoid falling in love with hypotheses, so that when unexpected findings appear, they arouse curiosity instead of fear. Dr. Greenleaf's legacy will include the John and Carol Greenleaf Award for prolific environmental and exercise-related publication in the Journal of Applied Physiology.

  3. A computer-based servo system for controlling isotonic contractions of muscle.

    Science.gov (United States)

    Smith, J P; Barsotti, R J

    1993-11-01

    We have developed a computer-based servo system for controlling isotonic releases in muscle. This system is a composite of commercially available devices: an IBM personal computer, an analog-to-digital (A/D) board, an Akers AE801 force transducer, and a Cambridge Technology motor. The servo loop controlling the force clamp is generated by computer via the A/D board, using a program written in QuickBASIC 4.5. Results are shown that illustrate the ability of the system to clamp the force generated by either skinned cardiac trabeculae or single rabbit psoas fibers down to the resolution of the force transducer within 4 ms. This rate is independent of the level of activation of the tissue and the size of the load imposed during the release. The key to the effectiveness of the system consists of two algorithms that are described in detail. The first is used to calculate the error signal to hold force to the desired level. The second algorithm is used to calculate the appropriate gain of the servo for a particular fiber and the size of the desired load to be imposed. The results show that the described computer-based method for controlling isotonic releases in muscle represents a good compromise between simplicity and performance and is an alternative to the custom-built digital/analog servo devices currently being used in studies of muscle mechanics.

  4. Efficient control of servo pneumatic actuator system utilizing by-pass ...

    Indian Academy of Sciences (India)

    The issue of energy saving nowadays is very crucial. Pneumatic systems, constituting an important segment of almost every industry, represent large energy consumers. Also, a significant problem with servo pneumatic actuators is achieving accuracy in positioning. The higher the positioning accuracy, the higher the ...

  5. Feature tracking for visual servo based range regulation on a mobile robot

    CSIR Research Space (South Africa)

    Burke, Michael G

    2009-11-01

    Full Text Available This poster presents a visual servo approach to straight line range and velocity regulation. The difference in velocity between a lead mobile robot and a follower is regulated through velocity control of the follower, in order to maintain a constant...

  6. Lung function studied by servo-controlled ventilator and respiratory mass spectrometer

    International Nuclear Information System (INIS)

    Piiper, J.

    1987-01-01

    The gas exchange function of lungs is studied. The gas concentration, measured by mass spectrometry and the lung volume and rate of change of lung volume are discussed. A servo-controlled ventilator is presented. Several experimental projects performed on anesthetized paralyzed dogs are reported. (M.A.C.) [pt

  7. The computer-aided design of a servo system as a multiple-criteria decision problem

    NARCIS (Netherlands)

    Udink ten Cate, A.J.

    1986-01-01

    This paper treats the selection of controller gains of a servo system as a multiple-criteria decision problem. In contrast to the usual optimization-based approaches to computer-aided design, inequality constraints are included in the problem as unconstrained objectives. This considerably simplifies

  8. A Matlab/Simulink-Based Interactive Module for Servo Systems Learning

    Science.gov (United States)

    Aliane, N.

    2010-01-01

    This paper presents an interactive module for learning both the fundamental and practical issues of servo systems. This module, developed using Simulink in conjunction with the Matlab graphical user interface (Matlab-GUI) tool, is used to supplement conventional lectures in control engineering and robotics subjects. First, the paper introduces the…

  9. Adaptive control of the radial servo system of a compact disc player

    NARCIS (Netherlands)

    Draijer, W.; Steinbuch, M.; Bosgra, O.H.

    1992-01-01

    The radial servo system of a compact disc player has to cope with large gain variations which are due to disc dependent optical characteristics, tolerances in mechanical and electrical components and nonlinearity in the generation of the position index. In current players this problem has been

  10. Image-based visual servo control using the port-Hamiltonian Approach

    NARCIS (Netherlands)

    Muñoz Arias, Mauricio; El Hawwary, Mohamed; Scherpen, Jacquelien M.A.

    2015-01-01

    This work is devoted to an image-based visual servo control strategy for standard mechanical systems in the port-Hamiltonian framework. We utilize a change of variables that transforms the port-Hamiltonian system into one with constant mass-inertia matrix, and we use an interaction matrix that

  11. A port-Hamiltonian approach to visual servo control of a pick and place system

    NARCIS (Netherlands)

    Dirksz, Daniel A.; Scherpen, Jacquelien M.A.

    2012-01-01

    In this paper we take a port-Hamiltonian approach to address the problem of image-based visual servo control of a pick and place system. We realize a closed-loop system, including the nonlinear camera dynamics, which is port-Hamiltonian. Although the closed-loop system is nonlinear, the resulting

  12. Performance verification and system parameter identification of spacecraft tape recorder control servo

    Science.gov (United States)

    Mukhopadhyay, A. K.

    1979-01-01

    Design adequacy of the lead-lag compensator of the frequency loop, accuracy checking of the analytical expression for the electrical motor transfer function, and performance evaluation of the speed control servo of the digital tape recorder used on-board the 1976 Viking Mars Orbiters and Voyager 1977 Jupiter-Saturn flyby spacecraft are analyzed. The transfer functions of the most important parts of a simplified frequency loop used for test simulation are described and ten simulation cases are reported. The first four of these cases illustrate the method of selecting the most suitable transfer function for the hysteresis synchronous motor, while the rest verify and determine the servo performance parameters and alternative servo compensation schemes. It is concluded that the linear methods provide a starting point for the final verification/refinement of servo design by nonlinear time response simulation and that the variation of the parameters of the static/dynamic Coulomb friction is as expected in a long-life space mission environment.

  13. A port-Hamiltonian approach to image-based visual servo control for dynamic systems

    NARCIS (Netherlands)

    Mahony, R.; Stramigioli, Stefano

    2012-01-01

    This paper introduces a port-Hamiltonian framework for the design of image-based visual servo control for dynamic mechanical systems. The approach taken introduces the concept of an image effort and provides an interpretation of energy exchange between the dynamics of the physical system and virtual

  14. A Port-Hamiltonian Approach to Visual Servo Control of a Pick and Place System

    NARCIS (Netherlands)

    Dirksz, Daniel A.; Scherpen, Jacquelien M. A.; Steinbuch, Maarten

    In this paper, we take a port-Hamiltonian approach to address the problem of image-based visual servo control of a pick and place system. Through a coordinate transformation and a passive interconnection between mechanical system and camera dynamics we realize a closed-loop system that is

  15. Model-based specification, analysis and synthesis of servo controllers for lithoscanners

    NARCIS (Netherlands)

    Schiffelers, R.; Alberts, W.; Voeten, J.P.M.

    2012-01-01

    ASML is the world's leading provider of complex lithography systems for the semiconductor industry. Such systems consist of numerous servo control systems. To design such control systems, a multi-disciplinary model-based development environment has been developed. It is based on a set of domain

  16. Exploiting H infinity sampled-data control theory for high-precision electromechanical servo control design

    NARCIS (Netherlands)

    Oomen, T.A.E.; Wal, van de M.M.J.; Bosgra, O.H.

    2006-01-01

    Optimal design of digital controllers for industrial electromechanical servo systems using an Hinf-criterion is considered. Present industrial practice is to perform the control design in the continuous time domain and to discretize the controller a posteriori. This procedure involves unnecessary

  17. Antenna servo control system characterization: Rate loop analysis for 34-m antenna at DSS 15

    Science.gov (United States)

    Nickerson, J. A.; Cox, D. G.; Smith, H. K.; Engel, J. H.; Ahlstrom, H. G.

    1986-01-01

    The elevation and azimuth servo rate loops at the 34-m High Efficiency Deep Space Station 15 (DSS 15) are described. Time and frequency response performance criteria were measured. The results are compared to theoretically deduced performance criteria. Unexpected anomalies in the frequency response are observed and identified.

  18. Adaptive Neural Network Control for Nonlinear Hydraulic Servo-System with Time-Varying State Constraints

    Directory of Open Access Journals (Sweden)

    Shu-Min Lu

    2017-01-01

    Full Text Available An adaptive neural network control problem is addressed for a class of nonlinear hydraulic servo-systems with time-varying state constraints. In view of the low precision problem of the traditional hydraulic servo-system which is caused by the tracking errors surpassing appropriate bound, the previous works have shown that the constraint for the system is a good way to solve the low precision problem. Meanwhile, compared with constant constraints, the time-varying state constraints are more general in the actual systems. Therefore, when the states of the system are forced to obey bounded time-varying constraint conditions, the high precision tracking performance of the system can be easily realized. In order to achieve this goal, the time-varying barrier Lyapunov function (TVBLF is used to prevent the states from violating time-varying constraints. By the backstepping design, the adaptive controller will be obtained. A radial basis function neural network (RBFNN is used to estimate the uncertainties. Based on analyzing the stability of the hydraulic servo-system, we show that the error signals are bounded in the compacts sets; the time-varying state constrains are never violated and all singles of the hydraulic servo-system are bounded. The simulation and experimental results show that the tracking accuracy of system is improved and the controller has fast tracking ability and strong robustness.

  19. Analysis of and H∞ Controller Design For An Electro-Hydraulic Servo Pressure Regulator

    DEFF Research Database (Denmark)

    Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole

    2011-01-01

    -circuit pumps are still hydraulically controlled, there is however still a need for being able to generate a hydraulic pilot pressure. The focus of the current paper is on the analysis and controller design of an electrohydraulic servo pressure regulator, which generates a hydraulic LS-pressure for a variable...

  20. Evaluation of Linear and Non-Linear Control Schemes Applied to a Hydraulic Servo System

    DEFF Research Database (Denmark)

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

    2005-01-01

    Due to the innovation of low-cost electronics such as sensors, microcontrollers etc., the focus on highperformance motion control is increasing. This work focuses on position control of single-input single-output hydraulic servo-systems in general. A hydraulically actuated robotic manipulator...

  1. Adaptive servo ventilation for central sleep apnoea in heart failure: SERVE-HF on-treatment analysis.

    Science.gov (United States)

    Woehrle, Holger; Cowie, Martin R; Eulenburg, Christine; Suling, Anna; Angermann, Christiane; d'Ortho, Marie-Pia; Erdmann, Erland; Levy, Patrick; Simonds, Anita K; Somers, Virend K; Zannad, Faiez; Teschler, Helmut; Wegscheider, Karl

    2017-08-01

    This on-treatment analysis was conducted to facilitate understanding of mechanisms underlying the increased risk of all-cause and cardiovascular mortality in heart failure patients with reduced ejection fraction and predominant central sleep apnoea randomised to adaptive servo ventilation versus the control group in the SERVE-HF trial.Time-dependent on-treatment analyses were conducted (unadjusted and adjusted for predictive covariates). A comprehensive, time-dependent model was developed to correct for asymmetric selection effects (to minimise bias).The comprehensive model showed increased cardiovascular death hazard ratios during adaptive servo ventilation usage periods, slightly lower than those in the SERVE-HF intention-to-treat analysis. Self-selection bias was evident. Patients randomised to adaptive servo ventilation who crossed over to the control group were at higher risk of cardiovascular death than controls, while control patients with crossover to adaptive servo ventilation showed a trend towards lower risk of cardiovascular death than patients randomised to adaptive servo ventilation. Cardiovascular risk did not increase as nightly adaptive servo ventilation usage increased.On-treatment analysis showed similar results to the SERVE-HF intention-to-treat analysis, with an increased risk of cardiovascular death in heart failure with reduced ejection fraction patients with predominant central sleep apnoea treated with adaptive servo ventilation. Bias is inevitable and needs to be taken into account in any kind of on-treatment analysis in positive airway pressure studies. Copyright ©ERS 2017.

  2. New method to improve dynamic stiffness of electro-hydraulic servo systems

    Science.gov (United States)

    Bai, Yanhong; Quan, Long

    2013-09-01

    Most current researches working on improving stiffness focus on the application of control theories. But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated, so the control action is lagged. Thus dynamic performance against force disturbance and dynamic load stiffness can’t be improved evidently by advanced control algorithms. In this paper, the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is analyzed. On this basis, the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put forward. And a scheme using double servo valves to realize flow feedforward compensation is presented, in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in time. The two valves are arranged in parallel to control the cylinder jointly. Furthermore, the model of flow compensation is derived, by which the product of the amplitude and width of the valve’s pulse command signal can be calculated. And determination rules of the amplitude and width of pulse signal are concluded by analysis and simulations. Using the proposed scheme, simulations and experiments at different positions with different force changes are conducted. The simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling time. That is, system dynamic load stiffness is evidently raised. This paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems.

  3. Sexual Orientation of Adult Sons of Gay Fathers.

    Science.gov (United States)

    Bailey, J. Michael; And Others

    1995-01-01

    Examined the sexual orientation of 82 adult sons of 55 gay men. Found that more than 90% of the sons whose sexual orientation could be rated were heterosexual. Gay and heterosexual sons did not differ on potentially relevant variables such as length of time they had lived with their fathers. (MDM)

  4. John Tyndall's religion: a fragment

    Science.gov (United States)

    Cantor, Geoffrey

    2015-01-01

    Both contemporaries and historians have focused on the high-profile 1874 Belfast Address in which John Tyndall was widely perceived as promulgating atheism. Although some historians have instead interpreted him as a pantheist or an agnostic, it is clear that any such labels do not accurately capture Tyndall's religious position throughout his life. By contrast, this paper seeks to chart Tyndall's religious journey from 1840 (when he was in his late teens) to the autumn of 1848 when he commenced his scientific studies at Marburg. Although he had been imbued with his father's stern conservative Irish Protestantism and opposition to Catholicism, as a youth he seems for a time to have been attracted to Methodism. Later, however, he questioned and rejected his father's religious views and was increasingly drawn to the more spiritual outlook of Ralph Waldo Emerson and Thomas Carlyle, along with a more radical attitude to politics.

  5. Robust control system for belt continuously variable transmission; Robust seigyo wo tekiyoshita mudan hensokuki no hensokuhi servo kei no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, K; Wakahara, T; Shimanaka, S; Yamamoto, M; Oshidari, T [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    The continuously variable transmission control system consists of generation of a desired gear ratio and a servo gear ratio system. The servo gear ratio system must provide the desired response at all times without being influenced by external disturbances. These include oil pressure as well as variation in performance due to operating conditions or changes occurring with us. We have developed the servo gear ratio system incorporating a robust model matching method, which enables the belt continuously variable transmission to satisfy this performance requirement. 2 refs., 9 figs.

  6. Memories of John N. Brady: scientist, mentor and friend

    Directory of Open Access Journals (Sweden)

    Marriott Susan J

    2009-05-01

    Full Text Available Abstract Friends and colleagues remember John N. Brady, Ph.D., Chief of the Virus Tumor Biology Section of the Laboratory of Cellular Oncology, who died much too young at the age of 57 on April 27, 2009 of colon cancer. John grew up in Illinois and received his Ph.D. with Dr. Richard Consigli at Kansas State University studying the molecular structure of polyomavirus. In 1984 John came to the National Institutes of Health as a Staff Fellow in the laboratory of Dr. Norman Salzman, Laboratory of Biology of Viruses NIAID, where he was among the first to analyze SV40 transcription using in vitro transcription systems and to analyze regulatory sequences for SV40 late transcription. He then trained with Dr. George Khoury in the Laboratory of Molecular Virology NCI, where he identified SV40 T-antigen as a transcriptional activator protein. His research interests grew to focus on the human retroviruses: human T-cell lymphotropic virus type I (HTLV-I and human immunodeficiency virus (HIV, analyzing how interactions between these viruses and the host cell influence viral gene regulation, viral pathogenesis and viral transformation. His research also impacted the fields of eukaryotic gene regulation and tumor suppressor proteins. John is survived by his wife, Laraine, and two sons, Matt and Kevin.

  7. Fusing Simulation Results From Multifidelity Aero-servo-elastic Simulators - Application To Extreme Loads On Wind Turbine

    DEFF Research Database (Denmark)

    Abdallah, Imad; Sudret, Bruno; Lataniotis, Christos

    2015-01-01

    Fusing predictions from multiple simulators in the early stages of the conceptual design of a wind turbine results in reduction in model uncertainty and risk mitigation. Aero-servo-elastic is a term that refers to the coupling of wind inflow, aerodynamics, structural dynamics and controls. Fusing...... the response data from multiple aero-servo-elastic simulators could provide better predictive ability than using any single simulator. The co-Kriging approach to fuse information from multifidelity aero-servo-elastic simulators is presented. We illustrate the co-Kriging approach to fuse the extreme flapwise...... bending moment at the blade root of a large wind turbine as a function of wind speed, turbulence and shear exponent in the presence of model uncertainty and non-stationary noise in the output. The extreme responses are obtained by two widely accepted numerical aero-servo-elastic simulators, FAST...

  8. Analysis of Dead Time and Implementation of Smith Predictor Compensation in Tracking Servo Systems for Small Unmanned Aerial Vehicles

    National Research Council Canada - National Science Library

    Brashear , Jr, Thomas J

    2005-01-01

    .... Gimbaled video camera systems, designed at NPS, use two servo actuators to command line of sight orientation via serial controller while tracking a target and is termed Visual Based Target Tracking (VBTT...

  9. Active control of residual tool marks for freeform optics functionalization by novel biaxial servo assisted fly cutting.

    Science.gov (United States)

    Zhu, Zhiwei; To, Suet; Zhang, Shaojian

    2015-09-01

    The inherent residual tool marks (RTM) with particular patterns highly affect optical functions of the generated freeform optics in fast tool servo or slow tool servo (FTS/STS) diamond turning. In the present study, a novel biaxial servo assisted fly cutting (BSFC) method is developed for flexible control of the RTM to be a functional micro/nanotexture in freeform optics generation, which is generally hard to achieve in FTS/STS diamond turning. In the BSFC system, biaxial servo motions along the z-axis and side-feeding directions are mainly adopted for primary surface generation and RTM control, respectively. Active control of the RTM from the two aspects, namely, undesired effect elimination or effective functionalization, are experimentally demonstrated by fabricating a typical F-theta freeform surface with scattering homogenization and two functional microstructures with imposition of secondary phase gratings integrating both reflective and diffractive functions.

  10. Obituary: John Louis Africano III, 1951-2006

    Science.gov (United States)

    Barker, Edwin, S.

    2007-12-01

    Technical Conference whose attendance expanded dramatically during his tenure. John moved to the NASA Johnson Space Center, Houston, Texas, in 1998 to work full time on orbital debris projects including the 3.0 meter Liquid Mirror Telescope and the CCD Debris Telescope in Cloudcroft, New Mexico. In 2000 he moved back to Colorado Springs, Colorado, to be closer to his family. From there he continued to support both the NASA Orbital Debris Program Office (ODPO) and AMOS. John was very instrumental in establishing cooperative programs between the ODPO and AMOS, which will benefit both organizations for many years to come. John left an indelible mark on his programs and all those who knew and loved him. The impact of his untimely departure will reverberate for many years. As John's wife Linda put it, "John is now visiting the stars and galaxies he adored from afar." John is survived by his wife, Linda Ann Africano; two sons, James Keith and Brian Michael; a daughter, Monica Lynn Africano; a sister, Diana Smith; and four grandchildren. The author acknowledges valuable input from Brian Africano (University of Colorado at Colorado Springs), Eugene Stansbery (NASA), Mark Mulrooney (NASA contractor), Tom Kelecy (Boeing LTS, Inc.), Paul Sydney (Boeing LTS, Inc.), Kira Abercromby (NASA contractor), and Patrick Seitzer (University of Michigan).

  11. Son Preference in Pakistan; A Myth or Reality.

    Science.gov (United States)

    Atif, Khaula; Ullah, Muhammad Zia; Afsheen, Afeera; Naqvi, Syed Abid Hassan; Raja, Zulqarnain Ashraf; Niazi, Saleem Asif

    2016-01-01

    To analyze desire for sons/daughters among ladies of Peshawar, Pakistan, with a view to rule out son preference and to study impact of various demographic characteristics on the subject. Cross-sectional descriptive study conducted at Combined Military Hospital, Peshawar, from August 2015 - January 2016; sampling technique was random/probability/non-purposive. Self-designed questionnaire was utilized; carrying questions pertinent to desire for sons/daughters during marital life, and demographic details. Data analyzed via descriptive analysis (SPSS-21), expressed as frequencies/percentages and mean ± standard deviation(minimum/maximum). Sons and daughters desired (dependent variables) were cross-tabulated with independent variables. Response rate was 63.25% (n-506). Data revealed following: Sons desired 3.05±2.061(1/12); Daughters desired 1.15±0.767(0/4); 6.1%(n-31) and 0.6%(n-3) desired infinite number of sons and daughters respectively, 18.2%(n-92) did not desire to have even one daughter, while 2.2%(n-11) considered it immaterial to have daughters or sons. There was a significant relation between sons desired and client's education (pGender discrimination can be attenuated by adequately addressing son preference at all tiers.

  12. Analysis of an controller design for an electro-hydraulic servo pressure regulator

    DEFF Research Database (Denmark)

    Pedersen, Henrik C.; Andersen, Torben Ole; Madsen, A. M.

    2009-01-01

    Mobile hydraulics is in a transition phase, where electronic sensors and digital signal processors are starting to become standard on a high number of machines, hereby replacing hydraulic pilot lines and oering new possibilities with regard to both control and feasibility. For controlling some...... of the existing hydraulic components there are, however, still a need for being able to generate a hydraulic pilot pressure, as e.g. almost all open-circuit pumps are hydraulically controlled. The focus of the current paper is therefore on the analysis and controller design an electro-hydraulic servo pressure...... regulator, which generates a hydraulic LS-pressure based on an electrical reference, hereby synergistically integrating knowledge from all parts of the mechatronics area. The servo pressure regulator is used to generate the LS-signal for a variable displacement pump, and the paper rst presents...

  13. Design of a Novel Servo-motorized Laser Device for Visual Pathways Diseases Therapy

    Directory of Open Access Journals (Sweden)

    Carlos Ignacio Sarmiento

    2015-12-01

    Full Text Available We discuss a novel servo-motorized laser device and a research protocol for visual pathways diseases therapies. The proposed servo-mechanized laser device can be used for potential rehabilitation of patients with hemianopia, quadrantanopia, scotoma, and some types of cortical damages. The device uses a semi spherical structure where the visual stimulus will be shown inside, according to a previous stimuli therapy designed by an ophthalmologist or neurologist. The device uses a pair of servomotors (with torque=1.5kg, which controls the laser stimuli position for the internal therapy and another pair for external therapy. Using electronic tools such as microcontrollers along with miscellaneous electronic materials, combined with LabVIEW based interface, a control mechanism is developed for the new device. The proposed device is well suited to run various visual stimuli therapies. We outline the major design principles including the physical dimensions, laser device’s kinematical analysis and the corresponding software development.

  14. Chiari malformation and central sleep apnea syndrome: efficacy of treatment with adaptive servo-ventilation

    Directory of Open Access Journals (Sweden)

    Jorge Marques do Vale

    2014-10-01

    Full Text Available The Chiari malformation type I (CM-I has been associated with sleep-disordered breathing, especially central sleep apnea syndrome. We report the case of a 44-year-old female with CM-I who was referred to our sleep laboratory for suspected sleep apnea. The patient had undergone decompressive surgery 3 years prior. An arterial blood gas analysis showed hypercapnia. Polysomnography showed a respiratory disturbance index of 108 events/h, and all were central apnea events. Treatment with adaptive servo-ventilation was initiated, and central apnea was resolved. This report demonstrates the efficacy of servo-ventilation in the treatment of central sleep apnea syndrome associated with alveolar hypoventilation in a CM-I patient with a history of decompressive surgery.

  15. Data-Driven Based Asynchronous Motor Control for Printing Servo Systems

    Science.gov (United States)

    Bian, Min; Guo, Qingyun

    Modern digital printing equipment aims to the environmental-friendly industry with high dynamic performances and control precision and low vibration and abrasion. High performance motion control system of printing servo systems was required. Control system of asynchronous motor based on data acquisition was proposed. Iterative learning control (ILC) algorithm was studied. PID control was widely used in the motion control. However, it was sensitive to the disturbances and model parameters variation. The ILC applied the history error data and present control signals to approximate the control signal directly in order to fully track the expect trajectory without the system models and structures. The motor control algorithm based on the ILC and PID was constructed and simulation results were given. The results show that data-driven control method is effective dealing with bounded disturbances for the motion control of printing servo systems.

  16. Image-Based Visual Servoing for Manipulation Via Predictive Control – A Survey of Some Results

    Directory of Open Access Journals (Sweden)

    Corneliu Lazăr

    2016-09-01

    Full Text Available In this paper, a review of predictive control algorithms developed by the authors for visual servoing of robots in manipulation applications is presented. Using these algorithms, a control predictive framework was created for image-based visual servoing (IBVS systems. Firstly, considering the point features, in the year 2008 we introduced an internal model predictor based on the interaction matrix. Secondly, distinctly from the set-point trajectory, we introduced in 2011 the reference trajectory using the concept from predictive control. Finally, minimizing a sum of squares of predicted errors, the optimal input trajectory was obtained. The new concept of predictive control for IBVS systems was employed to develop a cascade structure for motion control of robot arms. Simulation results obtained with a simulator for predictive IBVS systems are also presented.

  17. Investigation on Superior Performance by Fractional Controller for Cart-Servo Laboratory Set-Up

    Directory of Open Access Journals (Sweden)

    Ameya Anil Kesarkar

    2014-01-01

    Full Text Available In this paper, an investigation is made on the superiority of fractional PID controller (PI^alpha D^beta over conventional PID for the cart-servo laboratory set-up. The designed controllers are optimum in the sense of Integral Absolute Error (IAE and Integral Square Error (ISE. The paper contributes in three aspects: 1 Acquiring nonlinear mathematical model for the cart-servo laboratory set-up, 2 Designing fractional and integer order PID for minimizing IAE, ISE, 3 Analyzing the performance of designed controllers for simulated plant model as well as real plant. The results show a significantly superior performance by PI^alpha D^beta as compared to the conventional PID controller.

  18. Discrete Second-Order Sliding Mode Adaptive Controller Based on Characteristic Model for Servo Systems

    Directory of Open Access Journals (Sweden)

    Zhihong Wang

    2015-01-01

    Full Text Available Considering the varying inertia and load torque in high speed and high accuracy servo systems, a novel discrete second-order sliding mode adaptive controller (DSSMAC based on characteristic model is proposed, and a command observer is also designed. Firstly, the discrete characteristic model of servo systems is established. Secondly, the recursive least square algorithm is adopted to identify time-varying parameters in characteristic model, and the observer is applied to predict the command value of next sample time. Furthermore, the stability of the closed-loop system and the convergence of the observer are analyzed. The experimental results show that the proposed method not only can adapt to varying inertia and load torque, but also has good disturbance rejection ability and robustness to uncertainties.

  19. Detection of Surface Defects and Servo Signal Restoration for a Compact Disc Player

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2006-01-01

    Compact disc (CD) players have been on the market for more than two decades, and the involved technologies, including control are very mature. Some problems, however, still remain with respect to playing CDs having to surface defects like scratches and fingerprints. Two servo control loops are used...... to keep the optical pick-up unit (OPU) focused and radially locked to the information track of the CD. The problem is to design servo controllers which are well suited for both handling surface defects and disturbances like mechanical shocks. The handling of surface defects requires a low-controller...... bandwidth which is in conflict with the requirement for the handling of disturbances. This control problem can be solved by the use of a fault tolerant control strategy, where the fault detection is very important. The OPU feeds the controllers with detector signals. Based on these, focus and radial...

  20. Servo-controlling structure of five-axis CNC system for real-time NURBS interpolating

    Science.gov (United States)

    Chen, Liangji; Guo, Guangsong; Li, Huiying

    2017-07-01

    NURBS (Non-Uniform Rational B-Spline) is widely used in CAD/CAM (Computer-Aided Design / Computer-Aided Manufacturing) to represent sculptured curves or surfaces. In this paper, we develop a 5-axis NURBS real-time interpolator and realize it in our developing CNC(Computer Numerical Control) system. At first, we use two NURBS curves to represent tool-tip and tool-axis path respectively. According to feedrate and Taylor series extension, servo-controlling signals of 5 axes are obtained for each interpolating cycle. Then, generation procedure of NC(Numerical Control) code with the presented method is introduced and the method how to integrate the interpolator into our developing CNC system is given. And also, the servo-controlling structure of the CNC system is introduced. Through the illustration, it has been indicated that the proposed method can enhance the machining accuracy and the spline interpolator is feasible for 5-axis CNC system.

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

    Directory of Open Access Journals (Sweden)

    Yan Ren

    2013-01-01

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

  2. Characteristic Modeling and Control of Servo Systems with Backlash and Friction

    Directory of Open Access Journals (Sweden)

    Yifei Wu

    2014-01-01

    Full Text Available A novel approach for modeling and control of servo systems with backlash and friction is proposed based on the characteristic model. Firstly, to deal with friction-induced nonlinearities, a smooth Stribeck friction model is introduced. The backlash is modeled by a continuous and derivable mathematical function. Secondly, a characteristic model in the form of a second-order slowly time-varying difference equation is established and verified by simulations. Thirdly, a composite controller including the golden-section adaptive control law and the integral control law is designed and the stability of the closed-loop system is analyzed. The simulation and experimental results show that the proposed control scheme is effective and can improve the steady-state precision and the dynamic performance of the servo system with backlash and friction.

  3. Design and performance characteristic analysis of servo valve-type water hydraulic poppet valve

    International Nuclear Information System (INIS)

    Park, Sung Hwan

    2009-01-01

    For water hydraulic system control, the flow or pressure control using high-speed solenoid valve controlled by PWM control method could be a good solution for prevention of internal leakage. However, since the PWM control of on-off valves cause extensive flow and pressure fluctuation, it is difficult to control the water hydraulic actuators precisely. In this study, the servo valve-type water hydraulic valve using proportional poppet as the main valve is designed and the performance characteristics of the servo valve-type water hydraulic valve are analyzed. Furthermore, it is demonstrated through experiments that a decline in control chamber pressure that follows the change of pilot flow is caused by the occurrence of cavitation around the proportional poppet, and that fundamental characteristics of the developed valve remain unaffected by the occurrence of cavitation

  4. Enhancement of tracking performance in electro-optical system based on servo control algorithm

    Science.gov (United States)

    Choi, WooJin; Kim, SungSu; Jung, DaeYoon; Seo, HyoungKyu

    2017-10-01

    Modern electro-optical surveillance and reconnaissance systems require tracking capability to get exact images of target or to accurately direct the line of sight to target which is moving or still. This leads to the tracking system composed of image based tracking algorithm and servo control algorithm. In this study, we focus on the servo control function to minimize the overshoot in the tracking motion and do not miss the target. The scheme is to limit acceleration and velocity parameters in the tracking controller, depending on the target state information in the image. We implement the proposed techniques by creating a system model of DIRCM and simulate the same environment, validate the performance on the actual equipment.

  5. Numerical calculation for flow field of servo-tube guided hydraulic control rod driving system

    International Nuclear Information System (INIS)

    He Keyu; Han Weishi

    2010-01-01

    A new-style hydraulic control rod driving mechanism was put forward by using servo-tube control elements for the design of control rod driving mechanism. The results of numerical simulation by CFD program Fluent for flow field of hydraulic driving cylinder indicate that the bigger the outer diameter of servo-tube, the smaller the resistance coefficient of variable throttle orifice. The zero position gap of variable throttle orifice could be determined on 0.2 mm in the design. The pressure difference between the upper and nether surfaces of piston was mainly created by the throttle function of fixed throttle orifice. It can be effectively controlled by changing the gap of variable throttle orifice. And the lift force of driving cylinder is able to meet the requirement on the design load. (authors)

  6. High precision tracking control of a servo gantry with dynamic friction compensation.

    Science.gov (United States)

    Zhang, Yangming; Yan, Peng; Zhang, Zhen

    2016-05-01

    This paper is concerned with the tracking control problem of a voice coil motor (VCM) actuated servo gantry system. By utilizing an adaptive control technique combined with a sliding mode approach, an adaptive sliding mode control (ASMC) law with friction compensation scheme is proposed in presence of both frictions and external disturbances. Based on the LuGre dynamic friction model, a dual-observer structure is used to estimate the unmeasurable friction state, and an adaptive control law is synthesized to effectively handle the unknown friction model parameters as well as the bound of the disturbances. Moreover, the proposed control law is also implemented on a VCM servo gantry system for motion tracking. Simulations and experimental results demonstrate good tracking performance, which outperform traditional control approaches. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Inherent limitations of fixed-time, servo-controlled radiometric calorimetry

    International Nuclear Information System (INIS)

    Wetzel, J.R.; Lemming, J.F.; Duff, M.F.

    1987-01-01

    Interest has been shown in using fixed-time, servo-controlled calorimetry to shorten the measurement times for certain samples that require low precision values (3 to 5%). This type of calorimeter measurement could be particularly useful for screening scrap samples to determine whether there is a need for a more accurate measurement or for certain confirmatory measurements for which low precision numbers are sufficient. The equipment required for this type of measurement is a servo-controlled calorimeter and a preconditioning unit. Samples to be measured are placed in the preconditioning unit, which is maintained at the internal temperature of the calorimeter. The power value for the sample is determined at a fixed time after loading into the calorimeter, for example, 30 min. When a calorimeter is operated using a fixed cutoff time, there are additional sources of uncertainty that need to be considered. The major factors affecting the uncertainty of the calorimetry power values are discussed. 2 refs., 4 figs

  8. Servo-hydraulic actuator in controllable canonical form: Identification and experimental validation

    Science.gov (United States)

    Maghareh, Amin; Silva, Christian E.; Dyke, Shirley J.

    2018-02-01

    Hydraulic actuators have been widely used to experimentally examine structural behavior at multiple scales. Real-time hybrid simulation (RTHS) is one innovative testing method that largely relies on such servo-hydraulic actuators. In RTHS, interface conditions must be enforced in real time, and controllers are often used to achieve tracking of the desired displacements. Thus, neglecting the dynamics of hydraulic transfer system may result either in system instability or sub-optimal performance. Herein, we propose a nonlinear dynamical model for a servo-hydraulic actuator (a.k.a. hydraulic transfer system) coupled with a nonlinear physical specimen. The nonlinear dynamical model is transformed into controllable canonical form for further tracking control design purposes. Through a number of experiments, the controllable canonical model is validated.

  9. Control Servo-Visual de un Robot Manipulador Planar Basado en Pasividad

    Directory of Open Access Journals (Sweden)

    Carlos Soria

    2008-10-01

    Full Text Available Resumen: En este trabajo se diseña un controlador servo visual basado en la propiedad de pasividad del sistema visual. Se propone un regulador con ganancias de control variables, de tal manera que se evita la saturación de los actuadores y al mismo tiempo presenta la capacidad de corregir errores de pequeña magnitud. Asimismo el diseno se hace tenieñdo en cuenta el desempeño L2, a fin de darle capacidad de seguimiento de objetos en movimiento, con un error de control pequeño. Se muestran resultados experimentales realizados en un robot manipulador industrial tipo planar para verificar el cumplimiento de los objetivos del controlador propuesto. Palabras Clave: robot manipulador industrial, control servo visual, control no lineal, pasividad

  10. Optimality based repetitive controller design for track-following servo system of optical disk drives.

    Science.gov (United States)

    Chen, Wentao; Zhang, Weidong

    2009-10-01

    In an optical disk drive servo system, to attenuate the external periodic disturbances induced by inevitable disk eccentricity, repetitive control has been used successfully. The performance of a repetitive controller greatly depends on the bandwidth of the low-pass filter included in the repetitive controller. However, owing to the plant uncertainty and system stability, it is difficult to maximize the bandwidth of the low-pass filter. In this paper, we propose an optimality based repetitive controller design method for the track-following servo system with norm-bounded uncertainties. By embedding a lead compensator in the repetitive controller, both the system gain at periodic signal's harmonics and the bandwidth of the low-pass filter are greatly increased. The optimal values of the repetitive controller's parameters are obtained by solving two optimization problems. Simulation and experimental results are provided to illustrate the effectiveness of the proposed method.

  11. Application of prediction of equilibrium to servo-controlled calorimetry measurements

    International Nuclear Information System (INIS)

    Mayer, R.L. II.

    1987-01-01

    Research was performed to develop an endpoint prediction algorithm for use with calorimeters operating in the digital servo-controlled mode. The purpose of this work was to reduce calorimetry measurement times while maintaining the high degree of precision and low bias expected from calorimetry measurements. Data from routine operation of two calorimeters were used to test predictive models at each stage of development against time savings, precision, and robustness criteria. The results of the study indicated that calorimetry measurement times can be significantly reduced using this technique. The time savings is, however, dependent on parameters in the digital servo-control algorithm and on packaging characteristics of measured items. 7 refs., 4 figs., 1 tab

  12. Fault detection for discrete-time switched systems with sensor stuck faults and servo inputs.

    Science.gov (United States)

    Zhong, Guang-Xin; Yang, Guang-Hong

    2015-09-01

    This paper addresses the fault detection problem of switched systems with servo inputs and sensor stuck faults. The attention is focused on designing a switching law and its associated fault detection filters (FDFs). The proposed switching law uses only the current states of FDFs, which guarantees the residuals are sensitive to the servo inputs with known frequency ranges in faulty cases and robust against them in fault-free case. Thus, the arbitrarily small sensor stuck faults, including outage faults can be detected in finite-frequency domain. The levels of sensitivity and robustness are measured in terms of the finite-frequency H- index and l2-gain. Finally, the switching law and FDFs are obtained by the solution of a convex optimization problem. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Image-Based Visual Servoing for Robotic Systems: A Nonlinear Lyapunov-Based Control Approach

    International Nuclear Information System (INIS)

    Dixon, Warren

    2003-01-01

    The objective of this project is to enable current and future EM robots with an increased ability to perceive and interact with unstructured and unknown environments through the use of camera-based visual servo controllers. The scientific goals of this research are to develop a new visual servo control methodology that: (1) adapts for the unknown camera calibration parameters (e.g., focal length, scaling factors, camera position, and orientation) and the physical parameters of the robotic system (e.g., mass, inertia, friction), (2) compensates for unknown depth information (extract 3D information from the 2D image), and (3) enables multi-uncalibrated cameras to be used as a means to provide a larger field-of-view. Nonlinear Lyapunov-based techniques in conjunction with results from projective geometry are being used to overcome the complex control issues and alleviate many of the restrictive assumptions that impact current visual servo controlled robotic systems. The potential relevance of this control methodology will be a plug-and-play visual servoing control module that can be utilized in conjunction with current technology such as feature extraction and recognition, to enable current EM robotic systems with the capabilities of increased accuracy, autonomy, and robustness, with a larger field of view (and hence a larger workspace). These capabilities will enable EM robots to significantly accelerate D and D operations by providing for improved robot autonomy and increased worker productivity, while also reducing the associated costs, removing the human operator from the hazardous environments, and reducing the burden and skill of the human operators

  14. Image-Based Visual Servoing for Robotic Systems: A Nonlinear Lyapunov-Based Control Approach

    International Nuclear Information System (INIS)

    Dixon, Warren

    2002-01-01

    The objective of this project is to enable current and future EM robots with an increased ability to perceive and interact with unstructured and unknown environments through the use of camera-based visual servo controlled robots. The scientific goals of this research are to develop a new visual servo control methodology that: (1) adapts for the unknown camera calibration parameters (e.g., focal length, scaling factors, camera position and orientation) and the physical parameters of the robotic system (e.g., mass, inertia, friction), (2) compensates for unknown depth information (extract 3D information from the 2D image), and (3) enables multi-uncalibrated cameras to be used as a means to provide a larger field-of-view. Nonlinear Lyapunov-based techniques are being used to overcome the complex control issues and alleviate many of the restrictive assumptions that impact current visual servo controlled robotic systems. The potential relevance of this control methodology will be a plug-and-play visual servoing control module that can be utilized in conjunction with current technology such as feature extraction and recognition, to enable current EM robotic systems with the capabilities of increased accuracy, autonomy, and robustness, with a larger field of view (and hence a larger workspace). These capabilities will enable EM robots to significantly accelerate D and D operations by providing for improved robot autonomy and increased worker productivity, while also reducing the associated costs, removing the human operator from the hazardous environments, and reducing the burden and skill of the human operators

  15. Image-Based Visual Servoing for Robotic Systems: A Nonlinear Lyapunov-Based Control Approach

    International Nuclear Information System (INIS)

    Dixon, Warren

    2004-01-01

    There is significant motivation to provide robotic systems with improved autonomy as a means to significantly accelerate deactivation and decommissioning (DandD) operations while also reducing the associated costs, removing human operators from hazardous environments, and reducing the required burden and skill of human operators. To achieve improved autonomy, this project focused on the basic science challenges leading to the development of visual servo controllers. The challenge in developing these controllers is that a camera provides 2-dimensional image information about the 3-dimensional Euclidean-space through a perspective (range dependent) projection that can be corrupted by uncertainty in the camera calibration matrix and by disturbances such as nonlinear radial distortion. Disturbances in this relationship (i.e., corruption in the sensor information) propagate erroneous information to the feedback controller of the robot, leading to potentially unpredictable task execution. This research project focused on the development of a visual servo control methodology that targets compensating for disturbances in the camera model (i.e., camera calibration and the recovery of range information) as a means to achieve predictable response by the robotic system operating in unstructured environments. The fundamental idea is to use nonlinear Lyapunov-based techniques along with photogrammetry methods to overcome the complex control issues and alleviate many of the restrictive assumptions that impact current robotic applications. The outcome of this control methodology is a plug-and-play visual servoing control module that can be utilized in conjunction with current technology such as feature recognition and extraction to enable robotic systems with the capabilities of increased accuracy, autonomy, and robustness, with a larger field of view (and hence a larger workspace). The developed methodology has been reported in numerous peer-reviewed publications and the

  16. Servo-driven piezo common rail diesel injection system; Servogetriebene Piezo-Common-Rail-Dieseleinspritzung

    Energy Technology Data Exchange (ETDEWEB)

    Schoeppe, Detlev; Stahl, Christian; Krueger, Grit; Dian, Vincent [Continental Automotive GmbH, Regensburg (Germany). Geschaeftsbereich Engine Systems

    2012-03-15

    The requirements to be met by future diesel engines represent major challenges for fuel injection technology: Fuel consumption, emissions and noise development are to be further reduced without impairing driving enjoyment. To address these challenges, Continental has developed a new fuel injection system that features a high level of precision and accuracy. The key component is a servo-driven injector that is operated in a closed control circuit. (orig.)

  17. A servo controlled gradient loading triaxial model test system for deep-buried cavern

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xu-guang [College of Engineering, Ocean University of China, Qingdao 266100 (China); Shandong Provincial Key Laboratory of Ocean Engineering, Qingdao 266100 (China); Research Center of Geotechnical and Structural Engineering, Shandong University, Jinan 250061 (China); Zhang, Qiang-yong; Li, Shu-cai [Research Center of Geotechnical and Structural Engineering, Shandong University, Jinan 250061 (China)

    2015-10-15

    A servo controlled gradient loading model test system is developed to simulate the gradient geostress in deep-buried cavern. This system consists of the gradient loading apparatus, the digital servo control device, and the measurement system. Among them, the gradient loading apparatus is the main component which is used for exerting load onto the model. This loading apparatus is placed inside the counterforce wall/beam and is divided to several different loading zones, with each loading zone independently controlled. This design enables the gradient loading. Hence, the “real” geostress field surrounding the deep-buried cavern can be simulated. The loading or unloading process can be controlled by the human-computer interaction machines, i.e., the digital servo control system. It realizes the automation and visualization of model loading/unloading. In addition, this digital servo could control and regulate hydraulic loading instantaneously, which stabilizes the geostress onto the model over a long term. During the loading procedure, the collision between two adjacent loading platens is also eliminated by developing a guide frame. This collision phenomenon is induced by the volume shrinkage of the model when compressed in true 3D state. In addition, several accurate measurements, including the optical and grating-based method, are adopted to monitor the small deformation of the model. Hence, the distortion of the model could be accurately measured. In order to validate the performance of this innovative model test system, a 3D geomechanical test was conducted on a simulated deep-buried underground reservoir. The result shows that the radial convergence increases rapidly with the release of the stress in the reservoir. Moreover, the deformation increases with the increase of the gas production rate. This observation is consistence with field observation in petroleum engineering. The system is therefore capable of testing deep-buried engineering structures.

  18. Dynamic modeling and experiment of a new type of parallel servo press considering gravity counterbalance

    Science.gov (United States)

    He, Jun; Gao, Feng; Bai, Yongjun; Wu, Shengfu

    2013-11-01

    The large capacity servo press is traditionally realized by means of redundant actuation, however there exist the over-constraint problem and interference among actuators, which increases the control difficulty and the product cost. A new type of press mechanism with parallel topology is presented to develop the mechanical servo press with high stamping capacity. The dynamic model considering gravity counterbalance is proposed based on the virtual work principle, and then the effect of counterbalance cylinder on the dynamic performance of the servo press is studied. It is found that the motor torque required to operate the press is a lot less than the others when the ratio of the counterbalance force to the gravity of ram is in the vicinity of 1.0. The stamping force of the real press prototype can reach up to 25 MN on the position of 13 mm away from the bottom dead center. The typical deep-drawing process with 1 200 mm stroke at 8 strokes per minute is proposed by means of five order polynomial. On this process condition, the driving torques are calculated based on the above dynamic model and the torque measuring test is also carried out on the prototype. It is shown that the curve trend of calculation torque is consistent to the measured result and that the average error is less than 15%. The parallel mechanism is introduced into the development of large capacity servo press to avoid the over-constraint and interference of traditional redundant actuation, and its dynamic characteristics with gravity counterbalance are presented.

  19. Fault Detection and Severity Analysis of Servo Valves Using Recurrence Quantification Analysis

    Science.gov (United States)

    2014-10-02

    method of false nearest neighbors, we found that the minimum embedding dimension for the system is d=2. Figure 3 shows the recurrence plots of the...manufacturing process planning method for the components of a complex mechatronic system . Applied Mathematical Modelling, 37(24), 9829–9845. Samadani, M...diagnostics of nonlinear systems . A detailed nonlinear math- ematical model of a servo electro-hydraulic system has been used to demonstrate the procedure

  20. New mode switching algorithm for the JPL 70-meter antenna servo controller

    Science.gov (United States)

    Nickerson, J. A.

    1988-01-01

    The design of control mode switching algorithms and logic for JPL's 70 m antenna servo controller are described. The old control mode switching logic was reviewed and perturbation problems were identified. Design approaches for mode switching are presented and the final design is described. Simulations used to compare old and new mode switching algorithms and logic show that the new mode switching techniques will significantly reduce perturbation problems.

  1. Evaluating transient performance of servo mechanisms by analysing stator current of PMSM

    Science.gov (United States)

    Zhang, Qing; Tan, Luyao; Xu, Guanghua

    2018-02-01

    Smooth running and rapid response are the desired performance goals for the transient motions of servo mechanisms. Because of the uncertain and unobservable transient behaviour of servo mechanisms, it is difficult to evaluate their transient performance. Under the effects of electromechanical coupling, the stator current signals of a permanent-magnet synchronous motor (PMSM) potentially contain the performance information regarding servo mechanisms in use. In this paper, a novel method based on analysing the stator current of the PMSM is proposed for quantifying the transient performance. First, a vector control model is constructed to simulate the stator current behaviour in the transient processes of consecutive speed changes, consecutive load changes, and intermittent start-stops. It is discovered that the amplitude and frequency of the stator current are modulated by the transient load torque and motor speed, respectively. The stator currents under different performance conditions are also simulated and compared. Then, the stator current is processed using a local means decomposition (LMD) algorithm to extract the instantaneous amplitude and instantaneous frequency. The sample entropy of the instantaneous amplitude, which reflects the complexity of the load torque variation, is calculated as a performance indicator of smooth running. The peak-to-peak value of the instantaneous frequency, which defines the range of the motor speed variation, is set as a performance indicator of rapid response. The proposed method is applied to both simulated data in an intermittent start-stops process and experimental data measured for a batch of servo turrets for turning lathes. The results show that the performance evaluations agree with the actual performance.

  2. A new state space model for the NASA/JPL 70-meter antenna servo controls

    Science.gov (United States)

    Hill, R. E.

    1987-01-01

    A control axis referenced model of the NASA/JPL 70-m antenna structure is combined with the dynamic equations of servo components to produce a comprehansive state variable (matrix) model of the coupled system. An interactive Fortran program for generating the linear system model and computing its salient parameters is described. Results are produced in a state variable, block diagram, and in factored transfer function forms to facilitate design and analysis by classical as well as modern control methods.

  3. A servo controlled gradient loading triaxial model test system for deep-buried cavern.

    Science.gov (United States)

    Chen, Xu-guang; Zhang, Qiang-yong; Li, Shu-cai

    2015-10-01

    A servo controlled gradient loading model test system is developed to simulate the gradient geostress in deep-buried cavern. This system consists of the gradient loading apparatus, the digital servo control device, and the measurement system. Among them, the gradient loading apparatus is the main component which is used for exerting load onto the model. This loading apparatus is placed inside the counterforce wall/beam and is divided to several different loading zones, with each loading zone independently controlled. This design enables the gradient loading. Hence, the "real" geostress field surrounding the deep-buried cavern can be simulated. The loading or unloading process can be controlled by the human-computer interaction machines, i.e., the digital servo control system. It realizes the automation and visualization of model loading/unloading. In addition, this digital servo could control and regulate hydraulic loading instantaneously, which stabilizes the geostress onto the model over a long term. During the loading procedure, the collision between two adjacent loading platens is also eliminated by developing a guide frame. This collision phenomenon is induced by the volume shrinkage of the model when compressed in true 3D state. In addition, several accurate measurements, including the optical and grating-based method, are adopted to monitor the small deformation of the model. Hence, the distortion of the model could be accurately measured. In order to validate the performance of this innovative model test system, a 3D geomechanical test was conducted on a simulated deep-buried underground reservoir. The result shows that the radial convergence increases rapidly with the release of the stress in the reservoir. Moreover, the deformation increases with the increase of the gas production rate. This observation is consistence with field observation in petroleum engineering. The system is therefore capable of testing deep-buried engineering structures.

  4. Reconfigurable Flight Control Design using a Robust Servo LQR and Radial Basis Function Neural Networks

    Science.gov (United States)

    Burken, John J.

    2005-01-01

    This viewgraph presentation reviews the use of a Robust Servo Linear Quadratic Regulator (LQR) and a Radial Basis Function (RBF) Neural Network in reconfigurable flight control designs in adaptation to a aircraft part failure. The method uses a robust LQR servomechanism design with model Reference adaptive control, and RBF neural networks. During the failure the LQR servomechanism behaved well, and using the neural networks improved the tracking.

  5. A servo controlled gradient loading triaxial model test system for deep-buried cavern

    International Nuclear Information System (INIS)

    Chen, Xu-guang; Zhang, Qiang-yong; Li, Shu-cai

    2015-01-01

    A servo controlled gradient loading model test system is developed to simulate the gradient geostress in deep-buried cavern. This system consists of the gradient loading apparatus, the digital servo control device, and the measurement system. Among them, the gradient loading apparatus is the main component which is used for exerting load onto the model. This loading apparatus is placed inside the counterforce wall/beam and is divided to several different loading zones, with each loading zone independently controlled. This design enables the gradient loading. Hence, the “real” geostress field surrounding the deep-buried cavern can be simulated. The loading or unloading process can be controlled by the human-computer interaction machines, i.e., the digital servo control system. It realizes the automation and visualization of model loading/unloading. In addition, this digital servo could control and regulate hydraulic loading instantaneously, which stabilizes the geostress onto the model over a long term. During the loading procedure, the collision between two adjacent loading platens is also eliminated by developing a guide frame. This collision phenomenon is induced by the volume shrinkage of the model when compressed in true 3D state. In addition, several accurate measurements, including the optical and grating-based method, are adopted to monitor the small deformation of the model. Hence, the distortion of the model could be accurately measured. In order to validate the performance of this innovative model test system, a 3D geomechanical test was conducted on a simulated deep-buried underground reservoir. The result shows that the radial convergence increases rapidly with the release of the stress in the reservoir. Moreover, the deformation increases with the increase of the gas production rate. This observation is consistence with field observation in petroleum engineering. The system is therefore capable of testing deep-buried engineering structures

  6. A test of the "sexy son" hypothesis: sons of polygynous collared flycatchers do not inherit their fathers' mating status.

    Science.gov (United States)

    Gustafsson, Lars; Qvarnström, Anna

    2006-02-01

    According to the original "sexy son" hypothesis, a female may benefit from pairing with an already-mated male despite a reduction in fecundity because her sons inherit their father's attractiveness. We used data from a long-term study of collared flycatchers (Ficedula albicollis) collected during 24 years to test this prediction. Our results show that the sons of polygynously mated females fledged in poor condition and therefore did not inherit their father's large forehead patch (a condition-dependent display trait) or mating status. From the female's perspective, polygynous pairing resulted in fewer recruited grandchildren than did a monogamous pairing. The reproductive value of sons did not outweigh the fecundity costs of polygyny because the low paternal care reduced the attractiveness of sons. When there are long-lasting parental effects on offspring attractiveness, costs of polygyny may include the production of nonsexy sons.

  7. Analysis of High Speed Jets Produced by a Servo Tube Driven Liquid Jet Injector

    Science.gov (United States)

    Portaro, Rocco; Ng, Hoi Dick

    2017-11-01

    In today's healthcare environment many types of medication must be administered through the use of hypodermic needles. Although this practice has been in use for many years, drawbacks such as accidental needle stick injuries, transmission of deadly viruses and bio-hazardous waste are still present. This study focuses on improving a needle free technology known as liquid jet injection, through the implementation of a linear servo tube actuator for the construction of a fully closed loop liquid jet injection system. This device has the ability to deliver both micro- and macro- molecules, high viscosity fluids whilst providing real time control of the jet pressure profile for accurate depth and dispersion control. The experiments are conducted using a prototype that consists of a 3 kW servo tube actuator, coupled to a specially designed injection head allowing nozzle size and injection volume to be varied. The device is controlled via a high speed servo amplifier and FPGA. The high speed jets emanating from the injector are assessed via high speed photography and through the use of a force transducer. Preliminary results indicate that the system allows for accurate shaping of the jet pressure profile, making it possible to target different tissue depths/types accurately.

  8. A low-cost, FPGA-based servo controller with lock-in amplifier

    International Nuclear Information System (INIS)

    Yang, G; Barry, J F; Shuman, E S; Steinecker, M H; DeMille, D

    2012-01-01

    We describe the design and implementation of a low-cost, FPGA-based servo controller with an integrated waveform synthesizer and lock-in amplifier. This system has been designed with the specific application of laser frequency locking in mind but should be adaptable to a variety of other purposes as well. The system incorporates an onboard waveform synthesizer, a lock-in amplifier, two channels of proportional-integral (PI) servo control, and a ramp generator on a single FPGA chip. The system is based on an inexpensive, off-the-shelf FPGA evaluation board with a wide variety of available accessories, allowing the system to interface with standard laser controllers and detectors while minimizing the use of custom hardware and electronics. Gains, filter constants, and other relevant parameters are adjustable via onboard knobs and switches. These parameters and other information are displayed to the user via an integrated LCD, allowing full operation of the device without an accompanying computer. We demonstrate the performance of the system in a test setup, in which the frequency of a tunable external-cavity diode laser (ECDL) is locked to a resonant optical transmission peak of a Fabry-Perot cavity. In this setup, we achieve a total servo-loop bandwidth of ∼ 7 kHz and achieve locking of the ECDL to the cavity with a full-width-at-half-maximum (FWHM) linewidth of ∼ 200 kHz.

  9. Improving dynamic performances of PWM-driven servo-pneumatic systems via a novel pneumatic circuit.

    Science.gov (United States)

    Taghizadeh, Mostafa; Ghaffari, Ali; Najafi, Farid

    2009-10-01

    In this paper, the effect of pneumatic circuit design on the input-output behavior of PWM-driven servo-pneumatic systems is investigated and their control performances are improved using linear controllers instead of complex and costly nonlinear ones. Generally, servo-pneumatic systems are well known for their nonlinear behavior. However, PWM-driven servo-pneumatic systems have the advantage of flexibility in the design of pneumatic circuits which affects the input-output linearity of the whole system. A simple pneumatic circuit with only one fast switching valve is designed which leads to a quasi-linear input-output relation. The quasi-linear behavior of the proposed circuit is verified both experimentally and by simulations. Closed loop position control experiments are then carried out using linear P- and PD-controllers. Since the output position is noisy and cannot be directly differentiated, a Kalman filter is designed to estimate the velocity of the cylinder. Highly improved tracking performances are obtained using these linear controllers, compared to previous works with nonlinear controllers.

  10. Servo-control of water and sodium homeostasis during renal clearance measurements in conscious rats.

    Science.gov (United States)

    Thomsen, Klaus; Shirley, David G

    2007-01-01

    Servo-controlled fluid and sodium replacement during clearance studies is used in order to prevent loss of body fluid and sodium following diuretic/natriuretic procedures. However, even under control conditions, the use of this technique is sometimes associated with increases in proximal tubular fluid output (assessed by lithium clearance) and excretion rates. The present study examined the reason for these increases. The first series of experiments showed that one cause is volume overloading. This can occur if the servo system is activated from the start, i.e., during the establishment of a suitably high urine flow rate by constant infusion of hypotonic glucose solution. The second series of experiments showed that replacement of blood samples with donor blood can also lead to increases in fractional lithium excretion and accompanying increases in water and sodium excretion, a problem not seen when blood samples are replaced with the animal's own red blood cells resuspended in isotonic saline. When these pitfalls are avoided, servo-controlled sodium and fluid replacement is a reliable technique that makes it possible to study the effects of natriuretic and/or diuretic stimuli without interference from unwanted changes in extracellular volume. 2007 S. Karger AG, Basel

  11. Novel AC Servo Rotating and Linear Composite Driving Device for Plastic Forming Equipment

    Science.gov (United States)

    Liang, Jin-Tao; Zhao, Sheng-Dun; Li, Yong-Yi; Zhu, Mu-Zhi

    2017-07-01

    The existing plastic forming equipment are mostly driven by traditional AC motors with long transmission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In order to realize high performance forming processes, the driving device should be improved, especially for complicated processing motions. Based on electric servo direct drive technology, a novel AC servo rotating and linear composite driving device is proposed, which features implementing both spindle rotation and feed motion without transmission, so that compact structure and precise control can be achieved. Flux switching topology is employed in the rotating drive component for strong robustness, and fractional slot is employed in the linear direct drive component for large force capability. Then the mechanical structure for compositing rotation and linear motion is designed. A device prototype is manufactured, machining of each component and the whole assembly are presented respectively. Commercial servo amplifiers are utilized to construct the control system of the proposed device. To validate the effectiveness of the proposed composite driving device, experimental study on the dynamic test benches are conducted. The results indicate that the output torque can attain to 420 N·m and the dynamic tracking errors are less than about 0.3 rad in the rotating drive. the dynamic tracking errors are less than about 1.6 mm in the linear feed. The proposed research provides a method to construct high efficiency and accuracy direct driving device in plastic forming equipment.

  12. Fault Diagnosis for Hydraulic Servo System Using Compressed Random Subspace Based ReliefF

    Directory of Open Access Journals (Sweden)

    Yu Ding

    2018-01-01

    Full Text Available Playing an important role in electromechanical systems, hydraulic servo system is crucial to mechanical systems like engineering machinery, metallurgical machinery, ships, and other equipment. Fault diagnosis based on monitoring and sensory signals plays an important role in avoiding catastrophic accidents and enormous economic losses. This study presents a fault diagnosis scheme for hydraulic servo system using compressed random subspace based ReliefF (CRSR method. From the point of view of feature selection, the scheme utilizes CRSR method to determine the most stable feature combination that contains the most adequate information simultaneously. Based on the feature selection structure of ReliefF, CRSR employs feature integration rules in the compressed domain. Meanwhile, CRSR substitutes information entropy and fuzzy membership for traditional distance measurement index. The proposed CRSR method is able to enhance the robustness of the feature information against interference while selecting the feature combination with balanced information expressing ability. To demonstrate the effectiveness of the proposed CRSR method, a hydraulic servo system joint simulation model is constructed by HyPneu and Simulink, and three fault modes are injected to generate the validation data.

  13. WIT Diversity Talk with John Ellis

    CERN Multimedia

    CERN. Geneva; Ellis, Jonathan R.

    2017-01-01

    Sudeshna Datta Cockerill, CERN Ombudsperson, will interview John Ellis, a renown British theoretical physicist with a long career both at CERN and externally. John Ellis has also been awarded several prizes for his work in physics. Among many other outstanding roles and positions, he was Division Leader of the Theory Division at CERN from 1988-1994. John Ellis is currently Clerk Maxwell Professor of Theoretical Physics at King's College London.

  14. A Letter from a Black Mom to Her Son

    Science.gov (United States)

    Watson, Dyan

    2012-01-01

    An African American mother and teacher educator uses examples from her own childhood to describe how she hopes her child will be treated by teachers, and what she fears. In her letter to her son, the African American mom expresses how she want teachers to know her son's journey to school--metaphorically and physically. She wants them to know that…

  15. Son preference in rural China: patrilineal families and socioeconomic change.

    Science.gov (United States)

    Murphy, Rachel; Tao, Ran; Lu, Xi

    2011-01-01

    This article draws on a survey conducted in six provinces in summer 2008 to investigate the determinants of son preference in rural China. The analysis confirms the conventional wisdom that son preference is embedded within patrilineal family structures and practices. We extend our analysis by exploring specific aspects of variation within patrilineal family culture. We find that the patrilineal group (clan) composition of villages and family participation in practices such as building ancestral halls and updating genealogies significantly influence son preference. Yet even though son preference is embedded within patrilineal family culture, our analysis suggests that over time the attenuation of son preference is likely. This is because determinants associated with socioeconomic change—for instance, higher levels of education, direct exposure to official policy education materials, higher income (a proxy for rural industrialization), and agricultural mechanization—all attenuate son preference. Being younger and female are also associated with weaker son preference, and both characteristics are likely to interact with education and industrialization to further dilute son preference in the longer term. Nevertheless, our findings suggest that concerted efforts are needed to ameliorate institutional discrimination against rural people in welfare provisioning and in labor markets, and to promote multiple dimensions of gender equality, including in land rights, wage rates, and education.

  16. Son preference in a rural village in North Vietnam.

    Science.gov (United States)

    Bélanger, Danièle

    2002-12-01

    This article explores the continuing preference for sons in the context of low fertility in Vietnam. Although the total fertility rate for Vietnam declined from 6.0 children per woman of reproductive age in 1979 to 2.2 children in 1998, demographic evidence shows that son preference remains strong and influences contraceptive and fertility behavior. This study examines the underlying factors for son preference in a rural village in North Vietnam. The methodology includes focus-group discussions, an in-depth study of 25 families, and ethnographic observation. Results indicate that sons are highly desired for their social, symbolic, and economic value. In spite of four decades of socialist policies aimed at reducing gender-based inequalities and at weakening the patriarchal kinship system, the desire for sons continues to drive the family-building process. The article also indicates a gap between discourse and social practice with respect to roles assigned to children on the basis of their sex.

  17. PREFACE: John Desmond Bernal: Science and Society

    Science.gov (United States)

    Casey, Vincent

    2007-02-01

    you share my hope that in the not too distant future science may come to be used exclusively for the benefit of all mankind.'. On the occasion of the unveiling of a plaque by the 'National Committee for Science and Engineering Commemorative Plaques' in honour of J D Bernal in his hometown of Nenagh, Martin Bernal (JD's son) wrote 'Now, 35 years after his death, John Desmond Bernal has received this ultimate accolade'. It is to be hoped that this meeting and these proceedings will help further an awakening to Bernal's enduring bequest: 'his vision of science as inextricably tied to philosophy and to politics'—Helena Sheehan. Roy Johnston, an active 'bernalite' has been promoting the idea of a national Bernal Center or Institute in Ireland. Dare we hope for a more enlightened and scientifically informed social order? Acknowledgements I would like to acknowledge the help and support of my colleagues on the Munster Group of the IOPI, John Corr, Denise Gabuzda, Gabriel Gallagher, Niall Smith and particularly Leah Wallace who shared much of the responsibility for organising the meeting. Thanks are also due to Maria Hinfelaar, Director, Limerick Institute of Technology who gave the opening address and to Martin Bernal who closed the meeting with some personal reminiscences of times spent with his father. A big thank you to Sheila Gilheany and Alison Hackett, as always, for their support and encouragement and Peter van der Burgt for his help with the meeting website. The Munster Group of the Institute of Physics in Ireland would like to acknowledge with gratitude sponsorship of this event by Limerick Institute of Technology, University of Limerick (Research Office; J D Bernal Science and Society Centre; Physics Department), Institute of Physics History of Physics Group and the Institute of Chemistry of Ireland. Most memorable tours of areas of 'Bernal-interest' in Nenagh were organised for the speakers by Nancy Murphy of The Ormond Historical Society. Thanks also to North

  18. Project calculation of the steering mechanism hydraulic servo control in motor vehicles

    Directory of Open Access Journals (Sweden)

    Zoran Đukan Majkić

    2013-10-01

    Full Text Available Hydraulic servo controls are designed to facilitate rotation in place without providing increased ppower to steering wheels. In the initial design phase, the dimensions required for control systems are usually obtained through the calculation of their load when wheels rotate in place, where the torque is calculated empirically. The starting point in the project calculation is thus to determine the hydraulic power steering torque torsional resistance which is then used to determine the maximum value of force i.e. the torque on the stering wheel. The calculation of the control system servo control consists of determining the basic parameters, the required pump capacity, the main dimensions of the hub and the  pipeline and the conditions for the stability of the system control mechanism. Introduction The aim of the calculation of the steering control system is to determine the basic parameters of its components which ensure the fulfilment of requirements of the control system. Calculations are performed in several stages with a simultaneous  detailed constructive analysis of the control system leading to the best variant. At each stage, design and control calculations of the hydraulic servo of the steering mechanism are performed. The design allows the computation to complete the selection of basic dimensions of the amplifer elements, starting from the approved scheme and the basic building loads of approximate values. Calculations control is carried out to clarify the structural solution and to obtain the output characteristics of the control amplifier which are applied in the  estimation of  potential properties of the structure. Project calculation Baseline data must be sufficiently reliable, ie. must correspond to the construction characteristics of the vehicle design and the control system as well as to service conditions..A proper deterimination of the torque calculation of torsional resistance in wheels is of utmost importance. Moment of

  19. John Smithi kaks palet / Johannes Saar

    Index Scriptorium Estoniae

    Saar, Johannes, 1965-

    2003-01-01

    Näitus "John Smith. Marko ja Kaido" Tallinna Kunstihoones. Kaido Ole ja Marko Mäetamm esindavad rühmitusena "John Smith" Eestit 2003. a. Veneetsia biennaalil. Ilmunud ka kogumikus "Päevast päeva", lk. 90-96

  20. John of Salisbury on Aristotelian Science

    DEFF Research Database (Denmark)

    Bloch, David

    The First substantial treatment of John of Salisbury's views on Aristotelian science. Important for our understanding of the reception of Aristotle's works and for the history of theories of science.......The First substantial treatment of John of Salisbury's views on Aristotelian science. Important for our understanding of the reception of Aristotle's works and for the history of theories of science....

  1. John Kotter on Leadership, Management and Change.

    Science.gov (United States)

    Bencivenga, Jim

    2002-01-01

    Excerpts from interview with John Kotter, Konosuke Matsushita Professor of Leadership at the Harvard Business School, about his thoughts on the role of the superintendent as leader and manager. Describes his recent book "John P. Kotter on What Leaders Really Do," 1999. Lists eight-step change process from his book "Leading Change," 1996. (PKP)

  2. Obituary: John Norris Bahcall, 1934-2005

    Science.gov (United States)

    Striker, Jeremiah P.; Bahcall, Neta A.

    2007-12-01

    took. "I fell in love with Physics," he said, "and it changed my life." Bahcall graduated from Berkeley in 1956 with a degree in Physics. He received a master's degree from the University of Chicago, followed by a 1961 PhD in Physics from Harvard University. After a Research Fellowship at Indiana University working with Emil Konopinski on nuclear weak interactions, Bahcall received an invitation in 1962 to the California Institute of Technology (Caltech) to work with William A. Fowler, a Nobel Prize winner and expert in the field. Bahcall was working with Willy Fowler and others at the time and place that "nuclear astrophysics" was invented. There he became engaged with neutrino work and to Neta Assaf (then completing her PhD at Caltech) — the two constant loves of his life. John met Neta on a trip to Israel in 1965. She was a young physics graduate student "with a beautiful smile that stole my heart," he said. He spoke no Hebrew and she little English. After a dozen rejections, he got a date with her. They fell in love immediately and their love and friendship lasted a lifetime. "Marrying Neta was the best thing that ever happened to me," John frequently said. Safi Bahcall, their older son, recollects: "The persistence and never giving up was the theme for my dad; solar neutrinos, the Hubble Space Telescope, and the quest for scientific excellence are just a few other examples." Bahcall's first paper from Caltech, a one-page letter to the editor of the Astrophysical Journal, dated 1 December 1962 and entitled "The Solar Neutrino Flux" (written with Fowler, Icko Iben, and Richard Sears), proposed an experiment that might "provide a valuable experimental limit on the effective temperature for neutrino generation in the Sun". That paper set the course for a lifetime of research. The writing of scientific papers was, however, only one of Bahcall's many contributions to world science. He was an educator who changed the nature of postdoctoral training, and a scientific

  3. Obituary: Michael John Seaton, 1923-2007

    Science.gov (United States)

    Pradhan, Anil; Nahar, Sultana

    2007-12-01

    determine stellar opacities. The large-scale calculations revealed extensive features in photoionization such as resonances due to photoexcitation-of-core or PEC (as named by Seaton). The new opacities solved some outstanding problems and have been in use in some major astrophysical applications, recently by John Bahcall and others to explore discrepancies in solar elemental abundances from different models. A National Science Foundation reviewer once hailed the Opacity Project as the "crowning achievement of computational atomic physics." At an AAS meeting hosted by the Ohio State University in 1992, Seaton named a follow-up project "The Iron Project," focused particularly on the important Fe-peak elements, with many of the original members of the Opacity Project as participants. But Seaton himself remained preoccupied with improvements and applications of opacities. Seaton's most recent work was on radiative accelerations of elements in stars using the Opacity Project data and element diffusion in stellar interiors. Seaton continued to be highly active in research until his death at age 84, even writing large complex computer codes that now form the basis of an electronic database for opacities. There are precious few scientists who have his unique abilities that ranged from profound theoretical insights to mathematical formulations and highly technical computational developments. Mike Seaton was an immense source of inspiration to all who knew him. There is no doubt that his many students and collaborators, if ever paid a complement on their work, would surely reply: "I learnt the craft from a Master." Mike Seaton is survived by his wife Joy and their son Tony, and a son and daughter from his first marriage to Olive Singleton who passed away in 1958.

  4. Aero-servo-viscoelasticity theory: Lifting surfaces, plates, velocity transients, flutter, and instability

    Science.gov (United States)

    Merrett, Craig G.

    Modern flight vehicles are fabricated from composite materials resulting in flexible structures that behave differently from the more traditional elastic metal structures. Composite materials offer a number of advantages compared to metals, such as improved strength to mass ratio, and intentional material property anisotropy. Flexible aircraft structures date from the Wright brothers' first aircraft with fabric covered wooden frames. The flexibility of the structure was used to warp the lifting surface for flight control, a concept that has reappeared as aircraft morphing. These early structures occasionally exhibited undesirable characteristics during flight such as interactions between the empennage and the aft fuselage, or control problems with the elevators. The research to discover the cause and correction of these undesirable characteristics formed the first foray into the field of aeroelasticity. Aeroelasticity is the intersection and interaction between aerodynamics, elasticity, and inertia or dynamics. Aeroelasticity is well suited for metal aircraft, but requires expansion to improve its applicability to composite vehicles. The first is a change from elasticity to viscoelasticity to more accurately capture the solid mechanics of the composite material. The second change is to include control systems. While the inclusion of control systems in aeroelasticity lead to aero-servo-elasticity, more control possibilities exist for a viscoelastic composite material. As an example, during the lay-up of carbon-epoxy plies, piezoelectric control patches are inserted between different plies to give a variety of control options. The expanded field is called aero-servo-viscoelasticity. The phenomena of interest in aero-servo-viscoelasticity are best classified according to the type of structure considered, either a lifting surface or a panel, and the type of dynamic stability present. For both types of structures, the governing equations are integral

  5. The Telephone Connection: An Interview with Ernest Hemingway's Son.

    Science.gov (United States)

    Workman, Brooke

    1979-01-01

    Relates how a conference call to Ernest Hemingway's son, Gregory, resolved questions and brought understanding and excitement to a group of Iowa high school students enrolled in a 12-week Hemingway seminar. (FL)

  6. The discovery and exploration of Hang Son Doong

    Energy Technology Data Exchange (ETDEWEB)

    Limbert, H.; Limbert, D.; Hieu, N.; Phai, V. V.; Kinh Bac, D.; Phuong, T. H.; Granger, D.

    2016-08-01

    Hang Son Doong is located in the Phong Nha Ke Bang Limestone Massif in Quang Binh Province, Central Vietnam. Cave exploration by British cavers has been continuous in this area since 1990. Hang Son Doong is part of the Phong Nha Cave system which runs from the southern end of the National Park near the Lao border to the final resurgence at Phong Nha Cave. (Author)

  7. Cine-servo lens technology for 4K broadcast and cinematography

    Science.gov (United States)

    Nurishi, Ryuji; Wakazono, Tsuyoshi; Usui, Fumiaki

    2015-09-01

    Central to the rapid evolution of 4K image capture technology in the past few years, deployment of large-format cameras with Super35mm Single Sensors is increasing in TV production for diverse shows such as dramas, documentaries, wildlife, and sports. While large format image capture has been the standard in the cinema world for quite some time, the recent experiences within the broadcast industry have revealed a variety of requirement differences for large format lenses compared to those of the cinema industry. A typical requirement for a broadcast lens is a considerably higher zoom ratio in order to avoid changing lenses in the middle of a live event, which is mostly not the case for traditional cinema productions. Another example is the need for compact size, light weight, and servo operability for a single camera operator shooting in a shoulder-mount ENG style. On the other hand, there are new requirements that are common to both worlds, such as smooth and seamless change in angle of view throughout the long zoom range, which potentially offers new image expression that never existed in the past. This paper will discuss the requirements from the two industries of cinema and broadcast, while at the same time introducing the new technologies and new optical design concepts applied to our latest "CINE-SERVO" lens series which presently consists of two models, CN7x17KAS-S and CN20x50IAS-H. It will further explain how Canon has realized 4K optical performance and fast servo control while simultaneously achieving compact size, light weight and high zoom ratio, by referring to patent-pending technologies such as the optical power layout, lens construction, and glass material combinations.

  8. AeroPropulsoServoElasticity: Dynamic Modeling of the Variable Cycle Propulsion System

    Science.gov (United States)

    Kopasakis, George

    2012-01-01

    This presentation was made at the 2012 Fundamental Aeronautics Program Technical Conference and it covers research work for the Dynamic Modeling of the Variable cycle Propulsion System that was done under the Supersonics Project, in the area of AeroPropulsoServoElasticity. The presentation covers the objective for the propulsion system dynamic modeling work, followed by the work that has been done so far to model the variable Cycle Engine, modeling of the inlet, the nozzle, the modeling that has been done to model the affects of flow distortion, and finally presenting some concluding remarks and future plans.

  9. Servo-elastic dynamics of a hydraulic actuator pitching a blade with large deflections

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig; Kallesøe, Bjarne Skovmose

    2007-01-01

    This paper deals with the servo-elastic dynamics of a hydraulic pitch actuator acting on a largely bend wind turbine blade. The compressibility of the oil and flexibility of the hoses introduce a dynamic mode in the pitch bearing degree of freedom. This mode may obtain negative damping...... if the proportional gain on the actuator position error is defined too large relative to the viscous forces in the hydraulic system and the total rotational inertia of the pitch bearing degree of freedom. A simple expression for the stability limit of this proportional gain is derived for tuning the gain based...

  10. Using Feedback Error Learning for Control of Electro Hydraulic Servo System by Laguerre

    Directory of Open Access Journals (Sweden)

    Amir Reza Zare Bidaki

    2014-01-01

    Full Text Available In this paper, a new Laguerre controller is proposed to control the electro hydraulic servo system. The proposed controller uses feedback error learning method and leads to significantly improve performance in terms of settling time and amplitude of control signal rather than other controllers. All derived results are validated by simulation of nonlinear mathematical model of the system. The simulation results show the advantages of the proposed method for improved control in terms of both settling time and amplitude of control signal.

  11. A Simulation Model of Focus and Radial Servos in Compact Disc Players with Disc Surface Defects

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2004-01-01

    Compact Disc players have been on the market in more than two decades.As a consequence most of the control servo problems have been solved. A large remaining problem to solve is the handling of Compact Discs with severe surface defects like scratches and fingerprints. This paper introduces a method...... for making the design of controllers handling surface defects easier. A simulation model of Compact Disc players playing discs with surface defects is presented. The main novel element in the model is a model of the surface defects. That model is based on data from discs with surface defects. This model...

  12. L1 adaptive control of uncertain gear transmission servo systems with deadzone nonlinearity.

    Science.gov (United States)

    Zuo, Zongyu; Li, Xiao; Shi, Zhiguang

    2015-09-01

    This paper deals with the adaptive control problem of Gear Transmission Servo (GTS) systems in the presence of unknown deadzone nonlinearity and viscous friction. A global differential homeomorphism based on a novel differentiable deadzone model is proposed first. Since there exist both matched and unmatched state-dependent unknown nonlinearities, a full-state feedback L1 adaptive controller is constructed to achieve uniformly bounded transient response in addition to steady-state performance. Finally, simulation results are included to show the elimination of limit cycles, in addition to demonstrating the main results in this paper. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Servo-control for maintaining abdominal skin temperature at 36C in low birth weight infants.

    Science.gov (United States)

    Sinclair, J C

    2002-01-01

    Randomized trials have shown that the neonatal mortality rate of low birth-weight babies can be reduced by keeping them warm. For low birth-weight babies nursed in incubators, warm conditions may be achieved either by heating the air to a desired temperature, or by servo-controlling the baby's body temperature at a desired set-point. In low birth weight infants, to determine the effect on death and other important clinical outcomes of targeting body temperature rather than air temperature as the end-point of control of incubator heating. Standard search strategy of the Cochrane Neonatal Review Group. Searches were made of the Cochrane Controlled Trials Register (CCTR) (Cochrane Library, Issue 4, 2001) and MEDLINE, 1966 to November 2001. Randomized or quasi-randomized trials which test the effects of having the heat output of the incubator servo-controlled from body temperature compared with setting a constant incubator air temperature. Trial methodologic quality was systematically assessed. Outcome measures included death, timing of death, cause of death, and other clinical outcomes. Categorical outcomes were analyzed using relative risk and risk difference. Meta-analysis assumed a fixed effect model. Two eligible trials were found. In total, they included 283 babies and 112 deaths. Compared to setting a constant incubator air temperature of 31.8C, servo-control of abdominal skin temperature at 36C reduces the neonatal death rate among low birth weight infants: relative risk 0.72 (95% CI 0.54, 0.97); risk difference -12.7% (95% CI -1.6, -23.9). This effect is even greater among VLBW infants. During at least the first week after birth, low birth weight babies should be provided with a carefully regulated thermal environment that is near the thermoneutral point. For LBW babies in incubators, this can be achieved by adjusting incubator temperature to maintain an anterior abdominal skin temperature of at least 36C, using either servo-control or frequent manual

  14. An ultrasonic sensor controller for mapping and servo control in robotic systems

    International Nuclear Information System (INIS)

    Drotning, W.D.; Garcia, P. Jr.

    1993-03-01

    An ultrasonic sensor controller has been developed and applied in a variety of robotic systems for operation in hazardous environments. The controller consists of hardware and software that control multiple ultrasonic range sensors and provide workspace information to robot controllers for rapid, safe, and reliable operation in hazardous and remote environments. The hardware consists of a programmable multichannel controller that resides on a VMEbus for high speed communication to a multiprocessor architecture. The sensor controller has been used in a number of applications, which include providing high precision range information for proximity servo control of robots, and performing surface and obstacle mapping functions for safe path planning of robots in unstructured environments

  15. Smart Rotor Modeling: Aero-Servo-Elastic Modeling of a Smart Rotor with Adaptive Trailing Edge Flaps

    DEFF Research Database (Denmark)

    Bergami, Leonardo

    the trailing edge flap deflection to actively reduce the fatigue loads on the structure. The performance of the smart rotor configuration and its control algorithms are finally quantified by aero-servo-elastic simulations of the smart rotor turbine operating in a standard turbulent wind field.......This book presents the formulation of an aero-servo-elastic model for a wind turbine rotor equipped with Adaptive Trailing Edge Flaps (ATEF), a smart rotor configuration. As the name suggests, an aero-servo-elastic model consists of three main components: an aerodynamic model, a structural model......, and a control model. The book first presents an engineering type of aerodynamic model that accounts for the dynamic effects of flap deflection. The aerodynamic model is implemented in a Blade Element Momentum framework, and coupled with a multi-body structural model in the aero-servoelastic simulation code HAWC...

  16. Johns Hopkins Particulate Matter Research Center

    Data.gov (United States)

    Federal Laboratory Consortium — The Johns Hopkins Particulate Matter Research Center will map health risks of PM across the US based on analyses of national databases on air pollution, mortality,...

  17. 2008 St. Johns County, FL Countywide Lidar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Airborne terrestrial LiDAR was collected for St. Johns County, FL. System Parameters/Flight Plan. The LiDAR system acquisition parameters were developed based on a...

  18. John Dewey--Philosopher and Educational Reformer

    Science.gov (United States)

    Talebi, Kandan

    2015-01-01

    John Dewey was an American philosopher and educator, founder of the philosophical movement known as pragmatism, a pioneer in functional psychology, and a leader of the progressive movement in education in the United States.

  19. Vähesed head portfellihaldurid / John Mauldin

    Index Scriptorium Estoniae

    Mauldin, John

    2005-01-01

    USA investeerimisnõustaja olulisematest põhimõtetest ja -reeglitest portfellihaldurite valikul. Investeerimissüsteemi analüüsist, minevikutootluse väheolulisusest ja fondimaailmas ellujäämisvõimalustest. Vt. samas: John Maudlin

  20. John Bell and the Identical Twins

    CERN Multimedia

    1984-01-01

    A biographical profile of John S.Bell is presented based on extensive interviews the author had with Bell. Bell’s vierws on the quantum theory are presented along with a simple explanation of his idenity.

  1. THE MOTIF OF THE PRODIGAL SON IN IVAN TURGENEV'S NOVELS

    Directory of Open Access Journals (Sweden)

    Valentina Ivanovna Gabdullina

    2013-11-01

    Full Text Available The author questions the perception of Ivan Turgenev as a “non- Christian writer” and studies the problem of the prodigal son motif functioning in a series of his novels. In his novels, Turgenev pictured different phases of the archetypal story, originating from the Gospel parable of the prodigal son. In the novel Rudin he depicted the phase of spiritual wanderings of the hero who had lost touch with his native land — Russia. In his next novels (Home of the Gentry, Fathers and Sons and Smoke, after leading his hero in circles and sending him back to his paternal home, Turgenev reconstructs the model of human behavior, represented in the parable, thereby recognizing the immutability of the idea formalized in the Gospel. The motif of the return to Russian land gets its completion in Turgenev's last novel Virgin Soil, in which the author paradoxically connects the Westernist idea with the Gospel imperative. Solomin, the son of a deacon, sent by his wise father out to Europe “to get education”, studies in England, masters the European knowledge and returns back “to his native land” to establish his own business in inland Russia. Thus, a series of Turgenev's novels, in which he portrayed different phases of social life, are interlinked with the motif of the prodigal son, who is represented by novels' main characters.

  2. Translating The Infinities by John Banville

    OpenAIRE

    Irene Abigail Piccinini

    2015-01-01

    Abstract - John Banville’s talent as a prose stylist is widely recognized. The polished elegance of his phrases constitutes a continuing and fascinating challenge for his translator, due to the intricacies of the source text, its manifold registers and lexical choices. In his novel The Infinities, in Italian Teoria degli Infiniti, John Banville takes cue from Kleist’s Amphytrion to devise a novel where classicality interweaves with science and science fiction through the invention of a world ...

  3. Would John Stuart Mill have regulated pornography?

    OpenAIRE

    McGlynn, C.; Ward, I.

    2014-01-01

    John Stuart Mill dominates contemporary pornography debates where he is routinely invoked as an authoritative defence against regulation. This article, by contrast, argues that a broader understanding of Mill's ethical liberalism, his utilitarianism, and his feminism casts doubt over such an assumption. New insights into Mill's approach to sex, sexual activity, and the regulation of prostitution reveal an altogether more nuanced and activist approach. We conclude that John Stuart Mill would a...

  4. John Freind: physician, chemist, Jacobite, and friend of Voltaire's.

    Science.gov (United States)

    Rowlinson, J S

    2007-05-22

    John Freind (1675/76-1728) achieved distinction in several walks of life, first as a classical scholar, then as a physician and as a chemist who advocated Newtonian philosophy. His clinical practice was generally conservative and he was against the newly introduced practice of inoculating the smallpox. His principles were Tory and High Church; his loyalty to the house of Stuart involved him in the Jacobite plot of 1722, and a spell in the Tower of London. His money was part of the foundation of Dr Lee's benefaction to Christ Church, which still survives in name in scientific posts in Oxford. He was among the circle of friends that Voltaire formed during his two-year stay in England and, 50 years later, Voltaire took him and his son as the principal characters in a conte philosophique defending a deistic attitude against both atheism and revealed religion.

  5. A Novel Rotor and Stator Magnetic Fields Direct-Orthogonalized Vector Control Scheme for the PMSM Servo System

    Directory of Open Access Journals (Sweden)

    Shi-Xiong Zhang

    2014-02-01

    Full Text Available Permanent Magnet Synchronous motor (PMSM has received widespread acceptance in recent years. In this paper, a new rotor and stator Magnetic Fields Direct-Orthogonalized Vector Control (MFDOVC scheme is proposed for PMSM servo system. This method simplified the complex calculation of traditional vector control, a part of the system resource is economized. At the same time, through the simulation illustration validation, the performance of PMSM servo system with the proposed MFDOVC scheme can achieve the same with the complex traditional vector control method, but much simpler calculation is implemented using the proposed method.

  6. Use of a novel drainage flow servo-controlled CPB for mitral valve replacement in a Jehovah's Witness.

    Science.gov (United States)

    Niimi, Yoshinari; Murata, Seiichiro; Mitou, Yumi; Ohno, Yusuke

    2018-03-01

    We developed a novel open cardiopulmonary bypass (CPB) system, a drainage flow servo-controlled CPB system (DS-CPB), in which rotational speed of the main roller pump is servo-controlled to generate the same amount of flow as the systemic venous drainage. It was designed to safely decrease the priming volume while maintaining a constant reservoir level, even during fluctuations of the drainage flow. We report a successful use of a novel DS-CPB system in an elderly Jehovah's Witness patient with dehydration who underwent mitral valve replacement.

  7. The experience of sons caring for a parent with dementia.

    Science.gov (United States)

    McDonnell, Eilis; Ryan, Assumpta A

    2014-11-01

    This study explored the experiences of sons caring for a parent with dementia. Individual, semi-structured interviews were conducted with a purposeful sample of sons (n = 13) in a rural part of Ireland. Interviews were audiotaped, transcribed verbatim and analysed for common themes. The key themes that emerged were 'the parental bond', 'a binding role', 'coordinating care and support' and a 'getting on with it' approach to care. The study highlighted the commitment of sons to their caregiving role and the strong sense of duty that motivated them to provide care. The findings suggested that while many aspects of the caregiving experience such as lack of information and support are gender neutral, there are differences in the caregiving experiences of men and women in how they view their relationship with their parent and in the management of their caregiving role that merit further investigation. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  8. Obituary: Michael John Klein, 1940-2005

    Science.gov (United States)

    Gulkis, Samuel

    2006-12-01

    Michael John Klein died on 14 May 2005 at home in South Pasadena, California. The cause of death was tongue cancer that metastasized to the lungs. He was a non-smoker. Mike was a passionate radio astronomer, a trusted astronomical observer, an educator and a family man. Mike was born on 19 January 1940 in Ames, Iowa, the son of Florence Marie (Graf) and Fred Michael Klein. His mother was a homemaker, and his father was a banker. Mike had two older sisters, Lois Jean (Klein) Flauher and Marilyn June (Klein) Griffin. In 1962, Mike married his high school sweetheart Barbara Dahlberg, who survives him along with their three children, Kristin Marie (Klein) Shields, Michael John Klein Jr., Timothy Joel Klein, and six grandchildren. Mike developed a love for astronomy early in his life, and credited an early morning, newspaper-delivery route that he had at age twelve, which took him outside well before sunrise. He told family members that as he walked along his route, he stared into the sky and wondered what everything was. He studied sky charts, located stars, and began to understand how the planets shifted their positions relative to the stars each day. Another big influence in Mike's life was his brother in-law, Jim Griffin. Jim helped Mike understand that his passion for science did not have to remain a hobby, but could and should become a career. Jim's encouragement led Mike to attend Iowa State University in Ames, where he earned a BS in electrical engineering in 1962. Mike then started graduate school in electrical engineering at Michigan State, but after one semester transferred to the University of Michigan, Ann Arbor, where he earned an MS (1966) and PhD (1968) in astronomy. His doctoral dissertation, under the direction of Professor Fred Haddock, was based on extensive observations of the planets and examined the physical and thermal properties of planetary atmospheres and surfaces. Mike was awarded a Resident Research Associate position at JPL by the National

  9. Professor John Scott, folate and neural tube defects.

    Science.gov (United States)

    Hoffbrand, A Victor

    2014-02-01

    John Scott (1940-2013) was born in Dublin where he was to spend the rest of his career, both as an undergraduate and subsequently Professor of Biochemistry and Nutrition at Trinity College. His research with the talented group of scientists and clinicians that he led has had a substantial impact on our understanding of folate metabolism, mechanisms of its catabolism and deficiency. His research established the leading theory of folate involvement with vitamin B12 in the pathogenesis of vitamin B12 neuropathy. He helped to establish the normal daily intake of folate and the increased requirements needed either in food or as a supplement before and during pregnancy to prevent neural tube defects. He also suggested a dietary supplement of vitamin B12 before and during pregnancy to reduce the risk of neural tube defects. It would be an appropriate epitaph if fortification of food with folic acid became mandatory in the UK and Ireland, as it is in over 70 other countries. © 2013 John Wiley & Sons Ltd.

  10. Development of an EtherCAT enabled digital servo controller for the Green Bank Telescope

    Science.gov (United States)

    Whiteis, Peter G.; Mello, Melinda J.

    2012-09-01

    EtherCAT (Ethernet for Control Automation Technology) is gaining wide spread popularity in the automation industry as a real time field bus based on low cost, Ethernet hardware. EtherCAT maximizes use of 100Mbps Ethernet hardware by using a collision free ring topology, efficient Ethernet frame utilization (> 95%), and data exchange "on the fly". These characteristics enable EtherCAT to achieve Master to Slave node data exchange rates of > 1000 Hz. The Green Bank Telescope, commissioned in 2000, utilizes an analog control system for motion control of 8 elevation and 16 azimuth motors. This architecture, while sufficient for observations at frequencies up to 50GHz, has significant limitations for the current scientific goals of observing at 115GHz. Accordingly, the Green Bank staff has embarked on a servo upgrade project to develop a digital servo system which accommodates development and implementation of advanced control algorithms. This paper describes how the new control system requirements, use of existing infrastructure and budget constraints led us to define a distributed motion control architecture where EtherCAT real-time Ethernet was selected as the communication bus. Finally, design details are provided that describe how NRAO developed a custom EtherCAT-enabled motor controller interface for the GBT's legacy motor drives in order to provide technical benefits and flexibility not available in commercial products.

  11. Finite-time tracking control for multiple non-holonomic mobile robots based on visual servoing

    Science.gov (United States)

    Ou, Meiying; Li, Shihua; Wang, Chaoli

    2013-12-01

    This paper investigates finite-time tracking control problem of multiple non-holonomic mobile robots via visual servoing. It is assumed that the pinhole camera is fixed to the ceiling, and camera parameters are unknown. The desired reference trajectory is represented by a virtual leader whose states are available to only a subset of the followers, and the followers have only interaction. First, the camera-objective visual kinematic model is introduced by utilising the pinhole camera model for each mobile robot. Second, a unified tracking error system between camera-objective visual servoing model and desired reference trajectory is introduced. Third, based on the neighbour rule and by using finite-time control method, continuous distributed cooperative finite-time tracking control laws are designed for each mobile robot with unknown camera parameters, where the communication topology among the multiple mobile robots is assumed to be a directed graph. Rigorous proof shows that the group of mobile robots converges to the desired reference trajectory in finite time. Simulation example illustrates the effectiveness of our method.

  12. A Quasiphysics Intelligent Model for a Long Range Fast Tool Servo

    Science.gov (United States)

    Liu, Qiang; Zhou, Xiaoqin; Lin, Jieqiong; Xu, Pengzi; Zhu, Zhiwei

    2013-01-01

    Accurately modeling the dynamic behaviors of fast tool servo (FTS) is one of the key issues in the ultraprecision positioning of the cutting tool. Herein, a quasiphysics intelligent model (QPIM) integrating a linear physics model (LPM) and a radial basis function (RBF) based neural model (NM) is developed to accurately describe the dynamic behaviors of a voice coil motor (VCM) actuated long range fast tool servo (LFTS). To identify the parameters of the LPM, a novel Opposition-based Self-adaptive Replacement Differential Evolution (OSaRDE) algorithm is proposed which has been proved to have a faster convergence mechanism without compromising with the quality of solution and outperform than similar evolution algorithms taken for consideration. The modeling errors of the LPM and the QPIM are investigated by experiments. The modeling error of the LPM presents an obvious trend component which is about ±1.15% of the full span range verifying the efficiency of the proposed OSaRDE algorithm for system identification. As for the QPIM, the trend component in the residual error of LPM can be well suppressed, and the error of the QPIM maintains noise level. All the results verify the efficiency and superiority of the proposed modeling and identification approaches. PMID:24163627

  13. Dynamic parameter identification of robot arms with servo-controlled electrical motors

    Science.gov (United States)

    Jiang, Zhao-Hui; Senda, Hiroshi

    2005-12-01

    This paper addresses the issue of dynamic parameter identification of the robot manipulator with servo-controlled electrical motors. An assumption is made that all kinematical parameters, such as link lengths, are known, and only dynamic parameters containing mass, moment of inertia, and their functions need to be identified. First, we derive dynamics of the robot arm with a linear form of the unknown dynamic parameters by taking dynamic characteristics of the motor and servo unit into consideration. Then, we implement the parameter identification approach to identify the unknown parameters with respect to individual link separately. A pseudo-inverse matrix is used for formulation of the parameter identification. The optimal solution is guaranteed in a sense of least-squares of the mean errors. A Direct Drive (DD) SCARA type industrial robot arm AdeptOne is used as an application example of the parameter identification. Simulations and experiments for both open loop and close loop controls are carried out. Comparison of the results confirms the correctness and usefulness of the parameter identification and the derived dynamic model.

  14. Development of a Control System for PRIDE Remote Servo-manipulator

    International Nuclear Information System (INIS)

    Lee, Jong Kwang; Park, Byung Suk; Lee, Hyo Jik; Kim, Kyung Tae; Kim, Sung Hyun; Park, Hee Sung; Kim, Young Hwan; Jung, Jae Hoo; Kim, Ki Ho; Kim, Ho Dong

    2009-12-01

    KAERI is developing the PRIDE(PyRoprocess Integrated inactive DEmonstration) facility to verify the integrated performance of full Pyroprocess flow. A main process cell in the PRIDE facility will be filled with argon gas which prohibits direct access by human operators. Therefore, all the operation and maintenance of the process equipment is performed remotely through a master-slave manipulation. This research focuses on the design, fabrication, and interface of a control system which integrates several hardware systems such as a dual arm master-slave servo-manipulator, a horizontally moving transporter for a master manipulator, a bridge transporter for a slave manipulator, a chain hoist, camera systems and their display system, a manual console, and a pendant, etc. Also, a bilateral force-reflection controller considering an elasticity and vibration modes of wire cable has been developed for master-slave remote manipulation. The results obtained in this study will be applied for the force-reflection control of the bridge-transported master-slave servo-manipulator system for use in the PRIDE facility. Since this research is an essential work in robotics related fields, the results would be widely used for developing power manipulators and process automation equipment

  15. SYNTHESIS OF THE SERVO DRIVER WITH SPEED LOOP TUNED AT THE MODULAR OPTIMUM

    Directory of Open Access Journals (Sweden)

    Mr. Sergei V. Stelmashchuk

    2016-12-01

    Full Text Available The paper presents a method of synthesis of servo driver for controlling the speed of the object with the speed tuned at the modular optimum. An automatic electric motor drive is considered as the controlled element. This assumes the use of the speed sensor on the output shaft of the drive gear. This approach can be used for geared motors, which are more commonly used in a variety of compact drives. The technique is based on the method of synthesis by using logarithmic frequency response (LFR. The result is a synthesis of the two tracking angle controllers: proportional-integral and proportional-derivative (PIPD regulator. The criterion for the synthesis of tracking angle controller is the desired LFR, the characteristics of which are defined based on saturated capability transition function of controlled object with standard configuration for modular optimum. It is assumed that the maximum speed and acceleration of the transition functions are required for the synthesis of parameters of servo driver system by LFR. The article covers the accuracy and contains an example of a particular electric motor.

  16. Visual Servoing for an Autonomous Hexarotor Using a Neural Network Based PID Controller

    Science.gov (United States)

    Lopez-Franco, Carlos; Alanis, Alma Y.; Arana-Daniel, Nancy; Villaseñor, Carlos

    2017-01-01

    In recent years, unmanned aerial vehicles (UAVs) have gained significant attention. However, we face two major drawbacks when working with UAVs: high nonlinearities and unknown position in 3D space since it is not provided with on-board sensors that can measure its position with respect to a global coordinate system. In this paper, we present a real-time implementation of a servo control, integrating vision sensors, with a neural proportional integral derivative (PID), in order to develop an hexarotor image based visual servo control (IBVS) that knows the position of the robot by using a velocity vector as a reference to control the hexarotor position. This integration requires a tight coordination between control algorithms, models of the system to be controlled, sensors, hardware and software platforms and well-defined interfaces, to allow the real-time implementation, as well as the design of different processing stages with their respective communication architecture. All of these issues and others provoke the idea that real-time implementations can be considered as a difficult task. For the purpose of showing the effectiveness of the sensor integration and control algorithm to address these issues on a high nonlinear system with noisy sensors as cameras, experiments were performed on the Asctec Firefly on-board computer, including both simulation and experimenta results. PMID:28805689

  17. Visual Servoing for an Autonomous Hexarotor Using a Neural Network Based PID Controller.

    Science.gov (United States)

    Lopez-Franco, Carlos; Gomez-Avila, Javier; Alanis, Alma Y; Arana-Daniel, Nancy; Villaseñor, Carlos

    2017-08-12

    In recent years, unmanned aerial vehicles (UAVs) have gained significant attention. However, we face two major drawbacks when working with UAVs: high nonlinearities and unknown position in 3D space since it is not provided with on-board sensors that can measure its position with respect to a global coordinate system. In this paper, we present a real-time implementation of a servo control, integrating vision sensors, with a neural proportional integral derivative (PID), in order to develop an hexarotor image based visual servo control (IBVS) that knows the position of the robot by using a velocity vector as a reference to control the hexarotor position. This integration requires a tight coordination between control algorithms, models of the system to be controlled, sensors, hardware and software platforms and well-defined interfaces, to allow the real-time implementation, as well as the design of different processing stages with their respective communication architecture. All of these issues and others provoke the idea that real-time implementations can be considered as a difficult task. For the purpose of showing the effectiveness of the sensor integration and control algorithm to address these issues on a high nonlinear system with noisy sensors as cameras, experiments were performed on the Asctec Firefly on-board computer, including both simulation and experimenta results.

  18. Design of an Image-Servo Mask Alignment System Using Dual CCDs with an XXY Stage

    Directory of Open Access Journals (Sweden)

    Chih-Jer Lin

    2016-02-01

    Full Text Available Mask alignment of photolithography technology is used in many applications, such as micro electro mechanical systems’ semiconductor process, printed circuits board, and flat panel display. As the dimensions of the product are getting smaller and smaller, the automatic mask alignment of photolithography is becoming more and more important. The traditional stacked XY-Θz stage is heavy and it has cumulative flatness errors due to its stacked assembly mechanism. The XXY stage has smaller cumulative error due to its coplanar design and it can move faster than the traditional XY-Θz stage. However, the relationship between the XXY stage’s movement and the commands of the three motors is difficult to compute, because the movements of the three motors on the same plane are coupling. Therefore, an artificial neural network is studied to establish a nonlinear mapping from the desired position and orientation of the stage to three motors’ commands. Further, this paper proposes an image-servo automatic mask alignment system, which consists of a coplanar XXY stage, dual GIGA-E CCDs with lens and a programmable automatic controller (PAC. Before preforming the compensation, a self-developed visual-servo provides the positioning information which is obtained from the image processing and pattern recognition according to the specified fiducial marks. To obtain better precision, two methods including the center of gravity method and the generalize Hough Transformation are studied to correct the shift positioning error.

  19. Influence of Forming Conditions on Springback in V-bending Process Using Servo Press

    Science.gov (United States)

    Abe, Shinya; Takahashi, Susumu

    To improve fuel efficiency, aluminum alloys and high tensile steel sheets are increasingly being applied to automotive body parts. However, it is difficult to obtain accurate dimensions of formed parts. Therefore, technologies for reducing springback for the part formed by press are strongly demanded. It is said that the die holding time at the bottom dead center of a servo press slide can affect springback. To clarify the forming mechanisms of this phenomenon, a V bending test with a servo press was performed. Aluminum alloys sheets are applied as specimens. The location of press slide was measured by linear scales. It was found that the movement of the slide in a slide motion program differs from the actual movement of the slide. It is important to confirm if the slide is located in the position specified in the program. In addition, a springback angle measurement system is proposed that uses laser displacement measurement apparatus. Because it avoids human error, the proposed measurement system is more accurate than the image processing method.

  20. Development of a Control System for PRIDE Remote Servo-manipulator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Kwang; Park, Byung Suk; Lee, Hyo Jik; Kim, Kyung Tae; Kim, Sung Hyun; Park, Hee Sung; Kim, Young Hwan; Jung, Jae Hoo; Kim, Ki Ho; Kim, Ho Dong

    2009-12-15

    KAERI is developing the PRIDE(PyRoprocess Integrated inactive DEmonstration) facility to verify the integrated performance of full Pyroprocess flow. A main process cell in the PRIDE facility will be filled with argon gas which prohibits direct access by human operators. Therefore, all the operation and maintenance of the process equipment is performed remotely through a master-slave manipulation. This research focuses on the design, fabrication, and interface of a control system which integrates several hardware systems such as a dual arm master-slave servo-manipulator, a horizontally moving transporter for a master manipulator, a bridge transporter for a slave manipulator, a chain hoist, camera systems and their display system, a manual console, and a pendant, etc. Also, a bilateral force-reflection controller considering an elasticity and vibration modes of wire cable has been developed for master-slave remote manipulation. The results obtained in this study will be applied for the force-reflection control of the bridge-transported master-slave servo-manipulator system for use in the PRIDE facility. Since this research is an essential work in robotics related fields, the results would be widely used for developing power manipulators and process automation equipment.

  1. Control of xenon spatial oscillations during load follow of nuclear reactor via robust servo systems

    International Nuclear Information System (INIS)

    Ukai, Hiroyuki; Yada, Yukihiro; Iwazumi, Tetsuo; Morita, Yoshifumi.

    1990-01-01

    This paper investigates the control problem of xenon spatial oscillations in the axial direction during load following operations of a nuclear reactor. The system model is described by a one-group diffusion equation with xenon and power feedbacks and iodine-xenon dynamic equations and controlled by full-length and part-length control rods. In order to achieve the control purpose we formulate the control model as the design problem of robust servo systems for distributed parameter reactor systems. Hence the total thermal power and the axial offset are chosen as outputs to be controlled. The control law is designed based upon finite-dimensional systems which are constructed by linearizing around steady states, approximating by the Galerkin approximate method and reducing dimensions via the singular perturbation method. From a computational point of view a simple computational algorithm to obtain an approximate solution of the steady state neutron balance is developed via the perturbation method. Some results of numerical simulations are represented to show effectiveness of the theory developed in this paper. Particularly it is shown that the designed servo systems are robust against model errors with the linearization and the model truncation. (author)

  2. Optimization and performance characteristics of servo-piston hydraulic control rod drive mechanism

    International Nuclear Information System (INIS)

    Yu Mingrui; Han Weishi; Wang Ge

    2014-01-01

    This paper introduces the structure and working principles of the servo-piston hydraulic control rod drive mechanism (SHCM), which can be moved continuously and has self-lock capacity. The steady state characteristics of SHCM are simulated using FLUENT codes. Based on comparison with the experimental results, the simulation is proven to be credible as a tool to describe the steady state characteristics. Finally, the influence of structural parameters is analyzed to obtain an optimal design. The experimental results indicate that the traction of the servo-tube is larger in the starting and braking stages. The resistance coefficient of SHCM increases gradually in the starting and lifting stage, and then tends to be stable. This coefficient has a maximum value while the inlet pressure is low. Performance norms of SHCM, such as the anti-disturbance ability and positioning accuracy, are tested, the anti-disturbance ability of the actuator is strong while the inlet pressure is fluctuating. The positioning accuracy is high regardless of the action process (lifting or not). (author)

  3. Robust control for a biaxial servo with time delay system based on adaptive tuning technique.

    Science.gov (United States)

    Chen, Tien-Chi; Yu, Chih-Hsien

    2009-07-01

    A robust control method for synchronizing a biaxial servo system motion is proposed in this paper. A new network based cross-coupled control and adaptive tuning techniques are used together to cancel out the skew error. The conventional fixed gain PID cross-coupled controller (CCC) is replaced with the adaptive cross-coupled controller (ACCC) in the proposed control scheme to maintain biaxial servo system synchronization motion. Adaptive-tuning PID (APID) position and velocity controllers provide the necessary control actions to maintain synchronization while following a variable command trajectory. A delay-time compensator (DTC) with an adaptive controller was augmented to set the time delay element, effectively moving it outside the closed loop, enhancing the stability of the robust controlled system. This scheme provides strong robustness with respect to uncertain dynamics and disturbances. The simulation and experimental results reveal that the proposed control structure adapts to a wide range of operating conditions and provides promising results under parameter variations and load changes.

  4. Enhanced control of a flexure-jointed micromanipulation system using a vision-based servoing approach

    Science.gov (United States)

    Chuthai, T.; Cole, M. O. T.; Wongratanaphisan, T.; Puangmali, P.

    2018-01-01

    This paper describes a high-precision motion control implementation for a flexure-jointed micromanipulator. A desktop experimental motion platform has been created based on a 3RUU parallel kinematic mechanism, driven by rotary voice coil actuators. The three arms supporting the platform have rigid links with compact flexure joints as integrated parts and are made by single-process 3D printing. The mechanism overall size is approximately 250x250x100 mm. The workspace is relatively large for a flexure-jointed mechanism, being approximately 20x20x6 mm. A servo-control implementation based on pseudo-rigid-body models (PRBM) of kinematic behavior combined with nonlinear-PID control has been developed. This is shown to achieve fast response with good noise-rejection and platform stability. However, large errors in absolute positioning occur due to deficiencies in the PRBM kinematics, which cannot accurately capture flexure compliance behavior. To overcome this problem, visual servoing is employed, where a digital microscopy system is used to directly measure the platform position by image processing. By adopting nonlinear PID feedback of measured angles for the actuated joints as inner control loops, combined with auxiliary feedback of vision-based measurements, the absolute positioning error can be eliminated. With controller gain tuning, fast dynamic response and low residual vibration of the end platform can be achieved with absolute positioning accuracy within ±1 micron.

  5. Asymmetric Fuzzy Control of a Positive and Negative Pneumatic Pressure Servo System

    Science.gov (United States)

    Yang, Gang; Du, Jing-Min; Fu, Xiao-Yun; Li, Bao-Ren

    2017-11-01

    The pneumatic pressure control systems have been used in some fields. However, the researches on pneumatic pressure control mainly focus on constant pressure regulation. Poor dynamic characteristics and strong nonlinearity of such systems limit its application in the field of pressure tracking control. In order to meet the demand of generating dynamic pressure signal in the application of the hardware-in-the-loop simulation of aerospace engineering, a positive and negative pneumatic pressure servo system is provided to implement dynamic adjustment of sealed chamber pressure. A mathematical model is established with simulation and experiment being implemented afterwards to discuss the characteristics of the system, which shows serious asymmetry in the process of charging and discharging. Based on the analysis of the system dynamics, a fuzzy proportional integral derivative (PID) controller with asymmetric fuzzy compensator is proposed. Different from conventional adjusting mechanisms employing the error and change in error of the controlled variable as input parameters, the current chamber pressure and charging or discharging state are chosen as inputs of the compensator, which improves adaptability. To verify the effectiveness and performance of the proposed controller, the comparison experiments tracking sinusoidal and square wave commands are conducted. Experimental results show that the proposed controller can obtain better dynamic performance and relatively consistent control performance across the scope of work (2-140 kPa). The research proposes a fuzzy control method to overcome asymmetry and enhance adaptability for the positive and negative pneumatic pressure servo system.

  6. Experimental study on performance characteristics of servo-piston hydraulic control rod driving mechanism

    International Nuclear Information System (INIS)

    Yu Mingrui; Han Weishi; Zhou Jie; Liu Chunyu; Yang Zhida; Wang Ge

    2014-01-01

    An experimental study on the performance characteristics of the servo-piston hydraulic control rod driving mechanism is carried out, the dynamic processes of the driving mechanism are obtained through the experiments in different working conditions. Combined with the structure characteristics of the driving mechanism, the change rule between the characteristics parameters and the working condition is analyzed. The results indicate that the traction of the servo-tube decreases quickly at first, then slowly and finally trends to be a constant with the working pressure increasing, the tractions are the largest in the startup and deboost phases. The under pressure of the drive cylinder rises slowly and the upper pressure decreases rapidly at the beginning of the rise, the variation trend is opposite in the falling stage. There exists quick and clear flow change processes in the startup and deboost phases, the flow mutation value reduces and the mutation time changes a little with the working pressure increasing. The driving mechanism runs stable and has high sensitivity precision, the load does not vibrate at all when working conditions has small disturbance, a steady transform can be realized among every condition. (authors)

  7. Servo-controlled pneumatic pressure oscillator for respiratory impedance measurements and high-frequency ventilation.

    Science.gov (United States)

    Kaczka, David W; Lutchen, Kenneth R

    2004-04-01

    The ability to provide forced oscillatory excitation of the respiratory system can be useful in mechanical impedance measurements as well as high frequency ventilation (HFV). Experimental systems currently used for generating forced oscillations are limited in their ability to provide high amplitude flows or maintain the respiratory system at a constant mean pressure during excitation. This paper presents the design and implementation of a pneumatic pressure oscillator based on a proportional solenoid valve. The device is capable of providing forced oscillatory excitations to the respiratory system over a bandwidth suitable for mechanical impedance measurements and HVF. It delivers high amplitude flows (> 1.4 l/s) and utilizes a servo-control mechanism to maintain a load at a fixed mean pressure during simultaneous oscillation. Under open-loop conditions, the device exhibited a static hysteresis of approximately 7%, while its dynamic magnitude and phase responses were flat out to 10 Hz. Broad-band measurement of total harmonic distortion was approximately 19%. Under closed-loop conditions, the oscillator was able to maintain a mechanical test load at both positive and negative mean pressures during oscillatory excitations from 0.1 to 10.0 Hz. Impedance of the test load agreed closely with theoretical predictions. We conclude that this servo-controlled oscillator can be a useful tool for respiratory impedance measurements as well as HFV.

  8. Vision Servo Motion Control and Error Analysis of a Coplanar XXY Stage for Image Alignment Motion

    Directory of Open Access Journals (Sweden)

    Hau-Wei Lee

    2013-01-01

    Full Text Available In recent years, as there is demand for smart mobile phones with touch panels, the alignment/compensation system of alignment stage with vision servo control has also increased. Due to the fact that the traditional stacked-type XYθ stage has cumulative errors of assembly and it is heavy, it has been gradually replaced by the coplanar stage characterized by three actuators on the same plane with three degrees of freedom. The simplest image alignment mode uses two cameras as the equipments for feedback control, and the work piece is placed on the working stage. The work piece is usually engraved/marked. After the cameras capture images and when the position of the mark in the camera is obtained by image processing, the mark can be moved to the designated position in the camera by moving the stage and using alignment algorithm. This study used a coplanar XXY stage with 1 μm positioning resolution. Due to the fact that the resolution of the camera is about 3.75 μm per pixel, thus a subpixel technology is used, and the linear and angular alignment repeatability of the alignment system can achieve 1 μm and 5 arcsec, respectively. The visual servo motion control for alignment motion is completed within 1 second using the coplanar XXY stage.

  9. High mechanical advantage design of six-bar Stephenson mechanism for servo mechanical presses

    Directory of Open Access Journals (Sweden)

    Jianguo Hu

    2016-06-01

    Full Text Available This article proposed a two-phase design scheme of Stephenson six-bar working mechanisms for servo mechanical presses with high mechanical advantage. In the qualitative design phase, first, a Stephenson six-bar mechanism with a slide was derived from Stephenson six-bar kinematic chains. Second, based on the instant center analysis method, the relationship between mechanical advantage and some special instant centers was founded, and accordingly a primary mechanism configuration with high mechanical advantage was designed qualitatively. Then, a parameterized prototype model was established, and the influences of design parameters toward slide kinematical characteristics were analyzed. In the quantitative design phase, a multi-objective optimization model, aiming at high mechanical advantage and dwelling characteristics, was built, and a case design was done to find optimal dimensions. Finally, simulations based on the software ADAMS were conducted to compare the transmission characteristics of the optimized working mechanism with that of slide-crank mechanism and symmetrical toggle mechanism, and an experimental press was made to validate the design scheme. The simulation and experiment results show that, compared with general working mechanisms, the Stephenson six-bar working mechanism has higher mechanical advantage and better dwelling characteristics, reducing capacities and costs of servo motors effectively.

  10. Development of BLDC Electric Motor Control System In Hydraulic Servo Drive Based on Variable Hydrostatic Transmission

    Directory of Open Access Journals (Sweden)

    O. I. Tarasov

    2014-01-01

    Full Text Available Modern robotic systems require the use of servo drives. Owing to encoder and negative feedback these drives ensure highly accurate motion parameters. In case of autonomous systems drives must also have high power characteristics. Moreover, in most cases, it was impossible to select the motor so that the speed and torque on its shaft were in compliance with those of required by the actuator. To match these parameters different types of reducers are used. The article justifies and considers a selection criterion of the gear ratios for such transmission. For clarity, there is an example of selecting a motor and a gear for above transmission, taking into account the proposed criterion. In addition, the article discusses the advantages of using hydrostatic transmission in the drive, which monitors the angular position of the output level, in comparison with a mechanical gearbox. Due to the fact that, at the moment, BLDC motors have the best power characteristics, such a servo drive requires a special control system that will take into account the features of variable hydrostatic transmission and electric BLDC motor. Therefore, the paper proposes a structure of such a system and set out the principles of its construction. Various embodiments of sensor types that may be used in this system and their installation scheme explained.

  11. Digital simulation of FM-ZCS-quasi resonant converter fed DD servo drive using Matlab Simulink

    Directory of Open Access Journals (Sweden)

    Kattamuri Narasimha Rao

    2009-01-01

    Full Text Available This paper deals with digital simulation of FM-ZCS-quasi resonant converter fed DC servo drive using Matlab Simulink. Quasi Resonant Converter (QRC is fast replacing conventional PWM converters in high frequency operation. The salient feature of QRC is that the switching devices can be either switched on at zero voltage or switched off at zero current, so that switching losses are zero ideally. Switching stresses are low, volumes are low and power density is high. This property imparts high efficiency and high power density to the converters. The output of QRC is regulated by varying the switching frequency of the converter. Hence it is called Frequency modulated Zero current/zero voltage switching quasi resonant converter. The present work deals with simulation of DC Servo motor fed from ZCS-QRC using Matlab. Simulation results show that the ZCS-QRC's have low total harmonic distortion. The ZCS-QRC operating in half wave and full wave modes are simulated successfully. .

  12. Micro-vision servo control of a multi-axis alignment system for optical fiber assembly

    International Nuclear Information System (INIS)

    Chen, Weihai; Yu, Fei; Qu, Jianliang; Chen, Wenjie; Zhang, Jianbin

    2017-01-01

    This paper describes a novel optical fiber assembly system featuring a multi-axis alignment function based on micro-vision feedback control. It consists of an active parallel alignment mechanism, a passive compensation mechanism, a micro-gripper and a micro-vision servo control system. The active parallel alignment part is a parallelogram-based design with remote-center-of-motion (RCM) function to achieve precise rotation without fatal lateral motion. The passive mechanism, with five degrees of freedom (5-DOF), is used to implement passive compensation for multi-axis errors. A specially designed 1-DOF micro-gripper mounted onto the active parallel alignment platform is adopted to grasp and rotate the optical fiber. A micro-vision system equipped with two charge-coupled device (CCD) cameras is introduced to observe the small field of view and obtain multi-axis errors for servo feedback control. The two CCD cameras are installed in an orthogonal arrangement—thus the errors can be easily measured via the captured images. Meanwhile, a series of tracking and measurement algorithms based on specific features of the target objects are developed. Details of the force and displacement sensor information acquisition in the assembly experiment are also provided. An experiment demonstrates the validity of the proposed visual algorithm by achieving the task of eliminating errors and inserting an optical fiber to the U-groove accurately. (paper)

  13. Obituary: John W. Firor (1927-2007)

    Science.gov (United States)

    Gilman, Peter A.

    2009-12-01

    John W. Firor, a former Director of the High Altitude Observatory and the National Center for Atmospheric Research, and a founder of the Solar Physics Division of the American Astronomical Society, died of Alzheimer's disease in Pullman, Washington on November 5, 2007, he was 80. He was born in Athens Georgia on October 18, 1927, where his father was a professor of agricultural economics. John had an unusually diverse scientific career. His interest in physics and astrophysics began while serving in the army, during which time he was assigned to the Los Alamos National Laboratory, where he guarded highly radioactive materials (many have heard him describe how informal the protections were compared to later times). After his service he returned to college and graduated in physics from Georgia Tech in 1949. He received his Ph.D. from the University of Chicago in 1954, writing his thesis on cosmic rays under John Simpson. John Firor would later remark that: "If you needed cosmic rays to actually do anything, you are sunk." That thought, partly in jest, may help explain his motivation for moving to so many new scientific and management pursuits. John moved from cosmic ray physics to radio astronomy (particularly of the Sun) when he began work at the Carnegie Institution of Washington's Department of Terrestrial Magnetism, where he remained until 1961. During this time, he met Walter Orr Roberts, then the Director of the High Altitude Observatory (HAO) in Boulder, Colorado. HAO was then affiliated with the University of Colorado. In 1959, a movement began to upgrade the atmospheric sciences in the United States by establishing a National Center, where the largest, most important atmospheric research problems could be addressed. Roberts became the first Director of NCAR, as well as the first president of the University Corporation for Atmospheric Research (UCAR), the consortium of universities that was commissioned to manage and staff the new Center. HAO became a

  14. Types of sons/siblings, fraternal function and peers

    Directory of Open Access Journals (Sweden)

    Luisa Brunori

    2013-12-01

    Full Text Available In this article, the author starts by exploring family dynamics using the psychodynamic-groupanalytic paradigm to explore the intertwined relationships amongst the family figures like son, daughter, parents and sibling. The work focuses on the analysis of the psychological aspects related to siblings in the family, birth order and their consequences.

  15. Understanding Motherhood as Maturation: Maternity Scripts in Lois Lowry's "Son"

    Science.gov (United States)

    Deszcz-Tryhubczak, Justyna; Marecki, Mateusz

    2015-01-01

    When put together with the other parts of The Giver Quartet, "Son" (2012), Lowry's recently published concluding book, emerges as an odd exception to the focus on young adult protagonists since it foregrounds the mother's perspective and addresses the issue of motherhood. It presents the reader with at least three conceptual models of…

  16. Supersymmetric vector multiplets in nonadjoint representations of SO(N)

    International Nuclear Information System (INIS)

    Nishino, Hitoshi; Rajpoot, Subhash

    2007-01-01

    In the conventional formulation of N=1 supersymmetry, a vector multiplet is supposed to be in the adjoint representation of a given gauge group. We present a new formulation with a vector multiplet in the nonadjoint representation of SO(N) gauge group. Our basic algebra is [T I ,T J ]=f IJK T K , [T I ,U i ]=-(T I ) ij U j , [U i ,U j ]=-(T I ) ij T I , where T I are the generators of SO(N), while U i are the new ''generators'' in certain nonadjoint real representation R of SO(N). We use here the word generator in the broader sense of the word. Such a representation can be any real representation of SO(N) with the positive definite metric, satisfying (T I ) ij =-(T I ) ji and (T I ) [ij| (T I ) |k]l ≡0. The first nontrivial examples are the spinorial 8 S and conjugate spinorial 8 C representations of SO(8) consistent with supersymmetry. We further couple the system to chiral multiplets and show that a Higgs mechanism can give positive definite (mass) 2 to the new gauge fields for U i . We show an analogous system working with N=1 supersymmetry in 10D, and thereby N=4 system in 4D interacting with extra multiplets in the representation R. We also perform superspace reformulation as an independent confirmation

  17. A case of aneurysmal bone cyst in father and son

    International Nuclear Information System (INIS)

    Leithner, A.; Windhager, R.; Kainberger, F.; Lang, S.

    1998-01-01

    The authors report a familial case of primary aneurysmal bone cyst in father and son, affecting both at the same location at nearly the same age. This fact again raises the speculation of a genetic link as another factor in the pathogenesis of aneurysmal bone cyst

  18. La croissance demographique et son impact sur le developpement ...

    African Journals Online (AJOL)

    La croissance demographique et son impact sur le developpement des grandes villes au ... La ville de Porto-Novo au Bénin n'est pas en marge de cette réalité que ... and the need for improving its framework of life through its development.

  19. ¿Son los obreros idiotas e irracionales?

    Directory of Open Access Journals (Sweden)

    Francisco José León

    2010-01-01

    Full Text Available En este artículo presentamos un análisis crítico de la aproximación posmoderna y posestructuralista a la cuestión de la subjetividad obrera. El examen evidencia que: a algunas de sus proposiciones explicativas son internamente contradictorias o lógicamente inconsistentes; b en otras ocasiones la contradicción se produce entre las distintas proposiciones que la teoría ofrece para explicar un mismo fenómeno; c son frecuentes las contradicciones entre las proposiciones explicativas y los principios teóricos de los que se derivan; d es común la falta de inteligibilidad de las proposiciones; e abundan los "agujeros negros" en las cadenas de acontecimientos que se presentan como previos a la producción del efecto que pretenden explicar, y f muchas de sus proposiciones o bien no son plausibles empíricamente o simplemente no son empíricamente testables. Atribuimos a estas deficiencias la responsabilidad del fracaso de los autores posmodernos en su intento por recuperar la agencia obrera en los estudios del proceso de trabajo.

  20. SO(N) reformulated link invariants from topological strings

    International Nuclear Information System (INIS)

    Borhade, Pravina; Ramadevi, P.

    2005-01-01

    Large N duality conjecture between U(N) Chern-Simons gauge theory on S 3 and A-model topological string theory on the resolved conifold was verified at the level of partition function and Wilson loop observables. As a consequence, the conjectured form for the expectation value of the topological operators in A-model string theory led to a reformulation of link invariants in U(N) Chern-Simons theory giving new polynomial invariants whose integer coefficients could be given a topological meaning. We show that the A-model topological operator involving SO(N) holonomy leads to a reformulation of link invariants in SO(N) Chern-Simons theory. Surprisingly, the SO(N) reformulated invariants also has a similar form with integer coefficients. The topological meaning of the integer coefficients needs to be explored from the duality conjecture relating SO(N) Chern-Simons theory to A-model closed string theory on orientifold of the resolved conifold background

  1. The Transmission of Parenting from Fathers to Sons

    Science.gov (United States)

    Hofferth, Sandra L.; Pleck, Joseph H.; Vesely, Colleen K.

    2012-01-01

    SYNOPSIS Objective We address the extent to which parenting practices of fathers and mothers are associated with their sons’ parenting behaviors as young adults and whether adolescent behavior explains this association. Design Data come from 409 young men interviewed in the 2006 Young Adult study of the 1979 National Longitudinal Survey of Youth. Results Men whose fathers were positively involved with them when growing up report more positive parenting of their own children, a direct effect. Less harsh mothering and more positive fathering are associated with reduced adolescent behavior problems, and positive mothering is associated with positive adjustment of these young men as adolescents. However, neither adolescent problem behavior nor positive adjustment is associated with young men’s fathering of their own children, and thus does not explain the association between the fathering young men received and their own fathering behavior. Conclusions Men’s parenting of their sons can have a long-term direct effect on how their sons parent their own children. Although parenting is associated with both positive and negative behaviors of sons during adolescence, these adolescent behaviors are not directly linked to later parenting behavior when sons have their own children. More research is needed to examine mediation mechanisms for the intergenerational transmission of parenting. PMID:23284271

  2. Major ion chemistry of the Son River, India: Weathering processes ...

    Indian Academy of Sciences (India)

    solute flux and CDR values. The water chemistry indicates that the Son River water is good to excellent .... to separate suspended sediments and preserved at. 4◦C for further ...... and waste water, 20th edn; American Public Health. Association ...

  3. Major ion chemistry of the Son River, India: Weathering processes ...

    Indian Academy of Sciences (India)

    Major ion chemistry of the Son River, India: Weathering processes, dissolved fluxes and water quality assessment. Chinmaya Maharana, Sandeep Kumar Gautam,. Abhay Kumar Singh and Jayant K Tripathi. J. Earth Syst. Sci. 124(6) cO Indian Academy of Sciences. Supplementary data ...

  4. Major ion chemistry of the Son River, India

    Indian Academy of Sciences (India)

    The chemistry of major ions in the surface water of the Son River was studied in detail to determine various source(s) and processes controlling its water chemistry, seasonal and spatial variations in water chemistry, dissolved fluxes and chemical denudation rate (CDR). The study shows that Ca2+, Mg2+ and HCO 3 − are ...

  5. Reproductive Rights and Son Preference in India : Mobilizing ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This project is concerned with two overlapping manifestations of gender inequality in India : limited access to reproductive rights on the one hand, and practices associated with son preference on the other. Work that brings together these two issues is urgently needed, particularly in the context of declining funding for ...

  6. Benefits of Self-Organizing Networks (SON for Mobile Operators

    Directory of Open Access Journals (Sweden)

    Olav Østerbø

    2012-01-01

    Full Text Available Self-Organizing Networks (SON is a collection of functions for automatic configuration, optimization, diagnostisation and healing of cellular networks. It is considered to be a necessity in future mobile networks and operations due to the increased cost pressure. The main drivers are essentially to reduce CAPEX and OPEX, which would otherwise increase dramatically due to increased number of network parameters that has to be monitored and set, the rapidly increasing numbers of base stations in the network and parallel operation of 2G, 3G and Evolved Packet Core (EPC infrastructures. This paper presents evaluations on the use of some of the most important SON components. Mobile networks are getting more complex to configure, optimize and maintain. Many SON functions will give cost savings and performance benefits from the very beginning of a network deployment and these should be prioritized now. But even if many functions are already available and can give large benefits, the field is still in its infancy and more advanced functions are either not yet implemented or have immature implementations. It is therefore necessary to have a strategy for how and when different SON functions should be introduced in mobile networks.

  7. Adaptive servo ventilation for central sleep apnoea in heart failure : SERVE-HF on-treatment analysis

    NARCIS (Netherlands)

    Woehrle, Holger; Cowie, Martin R.; Eulenburg, Christine; Suling, Anna; Angermann, Christiane; d'Ortho, Marie-Pia; Erdmann, Erland; Levy, Patrick; Simonds, Anita K.; Somers, Virend K.; Zannad, Faiez; Teschler, Helmut; Wegscheider, Karl

    2017-01-01

    This on-treatment analysis was conducted to facilitate understanding of mechanisms underlying the increased risk of all-cause and cardiovascular mortality in heart failure patients with reduced ejection fraction and predominant central sleep apnoea randomised to adaptive servo ventilation versus the

  8. Obituary: John Louis Perdrix, 1926-2005

    Science.gov (United States)

    Orchiston, D. Wayne

    2006-12-01

    John Perdrix, astronomical historian and co-founder of the Journal of Astronomical History and Heritage, died on 27 June 2005. John Louis Perdrix was born in Adelaide, Australia, on 30 June 1926. After studying chemistry at Melbourne Technical College and working in industry, he joined the Commonwealth Scientific and Industrial Research Organisation's Division of Minerals and Geochemistry. In 1974 the Division relocated to the Western Australian capital, Perth, and John spent the rest of his working life there involved in geochemical research. From his teenage years John had a passion for astronomy, which he fine-tuned through the Astronomical Society of Victoria and the Victorian Branch of the British Astronomical Association. He was very active in both groups, serving as President of the former and Secretary/Treasurer of the latter. He was also an FRAS, and a member of the AAS, the BAA parent body, and the IAU (Commission 41)?no mean feat for an Australian amateur astronomer. Throughout his life, he was a strong advocate of close amateur-professional relations. John's main research interest was history of astronomy, and over the years he wrote a succession of research papers, mainly about aspects of Australian astronomy. His well-researched and neatly-illustrated papers on the Melbourne Observatory and the Great Melbourne Telescope are classics, and when the Observatory's future was in the balance they played a key role in the State Government's decision to convert this unique facility into a museum precinct. To support his research activities, John built up an amazing library that developed its own distinctive personality and quickly took over his house and garage before invading commercial storage facilities! Apart from writing papers, John had an even greater passion for editing and publishing. From 1985 to 1997 he produced the Australian Journal of Astronomy, and in 1998 this was replaced by the Journal of Astronomical History and Heritage (JAH2). Both

  9. 'SON-GO-KU' : a dream of automated library

    Science.gov (United States)

    Sato, Mamoru; Kishimoto, Juji

    In the process of automating libraries, the retrieval of books through the browsing of shelves is being overlooked. The telematic library is a document based DBMS which can deliver the content of books by simulating the browsing process. The retrieval actually simulates the process a person would use in selecting a book in a real library, where a visual presentation using a graphic display is substituted. The characteristics of prototype system "Son-Go-Ku" for such retrieval implemented in 1988 are mentioned.

  10. Integrating Equality - Globalization, Women's Rights, Son Preference and Human Trafficking

    OpenAIRE

    Cho, Seo-Young

    2011-01-01

    Employing economic and social globalization indicators, we empirically analyze whether globalization affects women’s rights in the economic and social dimensions. Using panel data from 150 countries over the 1981-2008 period, we find that social globalization positively affects both women’s economic and social rights, while the impact of economic globalization disappears when controlling for social globalization. Furthermore, we find that social globalization also reduces ‘son preference’ pro...

  11. Induced hypothermia for infants with hypoxic- ischemic encephalopathy using a servo-controlled fan: an exploratory pilot study.

    Science.gov (United States)

    Horn, Alan; Thompson, Clare; Woods, David; Nel, Alida; Bekker, Adrie; Rhoda, Natasha; Pieper, Clarissa

    2009-06-01

    Several trials suggest that hypothermia is beneficial in selected infants with hypoxic-ischemic encephalopathy. However, the cooling methods used required repeated interventions and were either expensive or reported significant temperature variation. The objective of this pilot study was to describe the use, efficacy, and physiologic impact of an inexpensive servo-controlled cooling fan blowing room-temperature air. A servo-controlled fan was manufactured and used to cool 10 infants with hypoxic-ischemic encephalopathy to a rectal temperature of 33 degrees C to 34 degrees C. The infants were sedated with phenobarbital, but clonidine was administered to some infants if shivering or discomfort occurred. A servo-controlled radiant warmer was used simultaneously with the fan to prevent overcooling. The settings used on the fan and radiant warmer differed slightly between some infants as the technique evolved. A rectal temperature of 34 degrees C was achieved in a median time of 58 minutes. Overcooling did not occur, and the mean temperature during cooling was 33.6 degrees C +/- 0.2 degrees C. Inspired oxygen requirements increased in 6 infants, and 5 infants required inotropic support during cooling, but this was progressively reduced after 1 to 2 days. Dehydration did not occur. Five infants shivered when faster fan speeds were used, but 4 of the 5 infants had hypomagnesemia. Shivering was controlled with clonidine in 4 infants, but 1 infant required morphine. Servo-controlled fan cooling with room-temperature air, combined with servo-controlled radiant warming, was an effective, simple, and safe method of inducing and maintaining rectal temperatures of 33 degrees C to 34 degrees C in sedated infants with hypoxic-ischemic encephalopathy. After induction of hypothermia, a low fan speed facilitated accurate temperature control, and warmer-controlled rewarming at 0.2 degrees C increments every 30 minutes resulted in more appropriate rewarming than when 0.5 degrees C

  12. Bathymetry (2011) for Fish Bay, St. John

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a LiDAR (Light Detection & Ranging) 0.3x0.3 meter resolution depth surface for Fish Bay, St. John in the U.S. Virgin Islands (USVI). The...

  13. The Bildungsroman in Cameroon Anglophone Literature: John ...

    African Journals Online (AJOL)

    This paper investigates the bildungsroman genre in postcolonial Cameroon Anglophone fiction through a textual analysis of John Nkemngong Nkengasong's Across the Mongolo and Margaret Afuh's Born before Her Time. It seeks to show that these two writers have borrowed a foreign genre and successfully manipulated ...

  14. Capitalism in Six Westerns by John Ford

    Science.gov (United States)

    Braun, Carlos Rodriguez

    2011-01-01

    The economic and institutional analysis of capitalism can be illustrated through John Ford's Westerns. This article focuses on six classics by Ford that show the move toward modern order, the creation of a new society, and the rule of law. Economic features are pervading, from property rights and contracts to markets, money, and trade. Ford has…

  15. John Dewey in the 21st Century

    Science.gov (United States)

    Williams, Morgan K.

    2017-01-01

    John Dewey was a pragmatist, progressivist, educator, philosopher, and social reformer (Gutek, 2014). Dewey's various roles greatly impacted education, and he was perhaps one of the most influential educational philosophers known to date (Theobald, 2009). Dewey's influence on education was evident in his theory about social learning; he believed…

  16. Preparing for Citizenship: Bring Back John Dewey

    Science.gov (United States)

    Pring, Richard

    2016-01-01

    The paper traces the development of citizenship in the curriculum in England since the 1960s, emerging particularly from the Crick report. It argues for lessons to be learnt from John Dewey's "Democracy and education", the centenary of which is being celebrated this year.

  17. We, John Dewey's Audience of Today

    Science.gov (United States)

    da Cunha, Marcus Vinicius

    2016-01-01

    This article suggests that John Dewey's "Democracy and Education" does not describe education in an existing society, but it conveys a utopia, in the sense coined by Mannheim: utopian thought aims at instigating actions towards the transformation of reality, intending to attain a better world in the future. Today's readers of Dewey (his…

  18. Jean Piaget's Debt to John Dewey

    Science.gov (United States)

    Tanner, Daniel

    2016-01-01

    Jean Piaget became a veritable institution unto himself in education and psychology, largely as the result of his developmental-stage theory advanced over the second quarter of the twentieth century. Not until Piaget was 73 did he make mention of John Dewey's work at Dewey's laboratory school, founded in 1894 at the University of Chicago. But here…

  19. John Deweys kritik af liberal education

    DEFF Research Database (Denmark)

    Huggler, Jørgen

    2017-01-01

    The paper deals with John Dewey's aversion against liberal education and his concern about a 'dual track' educational system separating liberal education and vocational education. It investigates the reason why Dewey maintains that the philosophical 'dualisms' culminate in the question on vocation....

  20. Astronaut John Glenn Enters Friendship 7

    Science.gov (United States)

    1962-01-01

    Astronaut John Glenn enters the Mercury spacecraft, Friendship 7, prior to the launch of MA-6 on February 20, 1961 and became the first American who orbited the Earth. The MA-6 mission was the first manned orbital flight boosted by the Mercury-Atlas vehicle, a modified Atlas ICBM (Intercontinental Ballistic Missile), lasted for five hours, and orbited the Earth three times.

  1. The Johns Hopkins Hospital: A Summer Internship

    OpenAIRE

    Smith, Adam

    2016-01-01

    Adam Smith, a native of Richmond, Indiana, is an advanced pharmacy practice student in the College of Pharmacy at Purdue University. In this article, he describes how career exploration through a summer internship with The Johns Hopkins Hospital in Baltimore, Maryland solidified his desire to pursue a career in pharmacy administration.

  2. John R. Commons: Pioneer in Labor Economics.

    Science.gov (United States)

    Barbash, Jack

    1989-01-01

    John R. Commons has contributed in one way or another to pratically every piece of social and labor legislation that has been enacted in the twentieth century. He has made his mark on such diverse aspects of American labor as apprenticeship, vocational education, workers' compensation, and the administration of labor law. (Author/JOW)

  3. John Maynard Smith (1920-2004)

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 11. John Maynard Smith (1920-2004) - “One of the last Grand Evolutionary Theorists of the 20th Century”. Vidyanand Nanjundiah. General Article Volume 10 Issue 11 November 2005 pp 70-78 ...

  4. In Memoriam: Dr. Frank John Fenner

    Centers for Disease Control (CDC) Podcasts

    This podcast reflects on one of the greatest pioneers in virology, Dr. Frank John Fenner. Dr. Frederick Murphy, a member of EID's editorial board and the Institute of Medicine, and professor of Pathology at the University of Texas Medical Branch in Galveston, shares professional and personal stories of Dr. Frank Fenner.

  5. Obituary: John Leroy Climenhaga, 1916-2008

    Science.gov (United States)

    Scarfe, Colin

    2009-01-01

    John Leroy Climenhaga was born on 7 November 1916 on a farm some 10 km from Delisle, a small town on the Canadian prairies, located about 50 km south-west of Saskatoon, Saskatchewan, and died at his home in Victoria, British Columbia, on 27 May 2008. His parents, Reuben and Elizabeth (nee Bert) Climenhaga, were farming folk, and he carried their honest and open attitude to the world throughout his life. John was the seventh born, and last to die, of their ten children. His father also served as an ordained minister of the Brethren in Christ. In early adulthood, John worked on his father's farm, but then attended the University of Saskatchewan, obtaining a B.A. with Honors in Mathematics and Physics and an M.A. in Physics, in 1945 and 1949 respectively. Between these events he worked as a Physics Instructor at Regina College from 1946 to 1948. In 1949 Climenhaga joined the faculty of Victoria College, as one of only two physicists in a small institution that was then part of the University of British Columbia. He remained in Victoria for the rest of his career, playing a major role in the College's growth into a full-fledged university, complete with thriving graduate programs in physics and astronomy as well as in many other fields. He served as Head of the Physics Department during the 1960s, a period which saw the College become the University of Victoria, with a full undergraduate program in Physics, and campaigned successfully for the establishment of a program in Astronomy, which began in 1965. From 1969 until 1972 he held the position of Dean of Arts and Science, and championed the university's participation in the Tri-University Meson Facility, whose high-current medium-energy beam was ideal for the production and study of mesons and their physics. That period was a turbulent one in the university's history, but John's integrity and his balanced and fair-minded approach to conflicts were of immeasurable importance in steering the young institution through it

  6. El último libro de John Strachey

    Directory of Open Access Journals (Sweden)

    Helcías Martán Góngora

    1965-08-01

    Full Text Available Fue muy largo el sendero ideológico que hubo de recorrer el inglés John Strachey en la busqueda íntima de una respuesta a su inquirir constante. En su viaje interior escuchó, a la siniestra, también la voz de las sirenas socialistas.

  7. John Smith - eesti kunstnik / Ants Juske

    Index Scriptorium Estoniae

    Juske, Ants, 1956-2016

    2006-01-01

    Marko Mäetamme ja Kaido Ole kollektiivsest loomingust, mida esitatakse John Smithi autorinime all, mõnda ka salapärase J. Smithi nn. biograafiast. Illustratsiooniks J. Smith'i "Jumalate maailm I (fragment). Õli, lõuend, 2002. Erakogu

  8. John Dewey on Philosophy and Childhood

    Science.gov (United States)

    Gregory, Maughn; Granger, David

    2012-01-01

    John Dewey was not a philosopher of education in the now-traditional sense of a doctor of philosophy who examines educational ends, means, and controversies through the disciplinary lenses of epistemology, ethics, and political theory, or of agenda-driven schools such as existentialism, feminism, and critical theory. Rather, Dewey was both an…

  9. Bathymetry (2011) for Coral Bay, St. John

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a LiDAR (Light Detection & Ranging) 0.3x0.3 meter resolution depth surface for Coral Bay, St. John in the U.S. Virgin Islands (USVI). The...

  10. Obituary: John J. Hillman, 1938-2006

    Science.gov (United States)

    Chanover, Nancy

    2007-12-01

    John J. Hillman, a dedicated NASA civil servant, spectroscopist, astrophysicist, planetary scientist, and mentor, died on February 12, 2006 of ocular melanoma at his home in Columbia, Maryland. His professional and personal interests were wide-reaching and varied, and he devoted his career to the advancement of our understanding of the beauty and wonder in the world around us. His love of nature, art, and science made him a true Renaissance man. John was born in Fort Jay, New York, on November 22, 1938, and was raised in Washington, D.C. He received his B.S., M.S., and Ph.D. degrees in Physics from American University in 1967, 1970, and 1975, respectively. He began working at NASA's Goddard Space Flight Center, then in its infancy, in 1969, juggling a full-time position as a Research Physicist, the completion of his M.S. and Ph.D. degrees, and a young family. His background in molecular spectroscopy enabled him to apply his skills to numerous disciplines within NASA: infrared and radio astronomy; electronic, vibrational, and rotational structure of interstellar molecules; solar and stellar atmospheres; and planetary atmospheres. He published more than 70 journal papers in these disciplines. He was a frequent contributor to the Ohio State University International Symposium on Molecular Spectroscopy, and possessed a rare ability to bridge the gap between laboratory and remote sensing spectroscopy, bringing scientists from different disciplines together to understand our Universe. The last fifteen years of John's career were devoted to the development of acousto-optic tunable filter (AOTF) cameras. He championed this technology as a low-cost, low-power alternative to traditional imaging cameras for in situ or remotely sensed planetary exploration. It was within this context that I got to know John, and eventually worked closely with him on the demonstration and application of this technology for planetary science using ground-based telescopes in New Mexico, California

  11. A Design Method for Fault Reconfiguration and Fault-Tolerant Control of a Servo Motor

    Directory of Open Access Journals (Sweden)

    Jing He

    2013-01-01

    Full Text Available A design scheme that integrates fault reconfiguration and fault-tolerant position control is proposed for a nonlinear servo system with friction. Analysis of the non-linear friction torque and fault in the system is used to guide design of a sliding mode position controller. A sliding mode observer is designed to achieve fault reconfiguration based on the equivalence principle. Thus, active fault-tolerant position control of the system can be realized. A real-time simulation experiment is performed on a hardware-in-loop simulation platform. The results show that the system reconfigures well for both incipient and abrupt faults. Under the fault-tolerant control mechanism, the output signal for the system position can rapidly track given values without being influenced by faults.

  12. Hankel Matrix Correlation Function-Based Subspace Identification Method for UAV Servo System

    Directory of Open Access Journals (Sweden)

    Minghong She

    2018-01-01

    Full Text Available For the identification problem of closed-loop subspace model, we propose a zero space projection method based on the estimation of correlation function to fill the block Hankel matrix of identification model by combining the linear algebra with geometry. By using the same projection of related data in time offset set and LQ decomposition, the multiplication operation of projection is achieved and dynamics estimation of the unknown equipment system model is obtained. Consequently, we have solved the problem of biased estimation caused when the open-loop subspace identification algorithm is applied to the closed-loop identification. A simulation example is given to show the effectiveness of the proposed approach. In final, the practicability of the identification algorithm is verified by hardware test of UAV servo system in real environment.

  13. Propulsion System Dynamic Modeling of the NASA Supersonic Concept Vehicle for AeroPropulsoServoElasticity

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph W.; Seiel, Jonathan

    2016-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report

  14. Pneumatic Rotary Actuator Position Servo System Based on ADE-PD Control

    Directory of Open Access Journals (Sweden)

    Yeming Zhang

    2018-03-01

    Full Text Available In order to accurately control the rotation position of a pneumatic rotary actuator, the flow state of the gas and the motion state of the pneumatic rotary actuator in the pneumatic rotary actuator position servo system are analyzed in this paper. The mathematical model of the system and the experiment platform are established after that. An Adaptive Differential Evolution (ADE algorithm which adaptively ameliorates the scaling factor and crossover probability in the process of individual evolution is proposed and applied to the parameter optimization of PD controller. The experimental platform is used to compare the controller with Differential Evolution (DE algorithm and NCD-PID controller. Finally, the characteristics of the system are tested by increasing the inertial load. The experimental results illustrate that system using ADE-PD control strategy has greater position precision and faster response than using DE-PD and NCD-PID strategies, and shows great robustness.

  15. Optimization of Smart Structure for Improving Servo Performance of Hard Disk Drive

    Science.gov (United States)

    Kajiwara, Itsuro; Takahashi, Masafumi; Arisaka, Toshihiro

    Head positioning accuracy of the hard disk drive should be improved to meet today's increasing performance demands. Vibration suppression of the arm in the hard disk drive is very important to enhance the servo bandwidth of the head positioning system. In this study, smart structure technology is introduced into the hard disk drive to suppress the vibration of the head actuator. It has been expected that the smart structure technology will contribute to the development of small and light-weight mechatronics devices with the required performance. First, modeling of the system is conducted with finite element method and modal analysis. Next, the actuator location and the control system are simultaneously optimized using genetic algorithm. Vibration control effect with the proposed vibration control mechanisms has been evaluated by some simulations.

  16. Compensating Unknown Time-Varying Delay in Opto-Electronic Platform Tracking Servo System

    Directory of Open Access Journals (Sweden)

    Ruihong Xie

    2017-05-01

    Full Text Available This paper investigates the problem of compensating miss-distance delay in opto-electronic platform tracking servo system. According to the characteristic of LOS (light-of-sight motion, we setup the Markovian process model and compensate this unknown time-varying delay by feed-forward forecasting controller based on robust H∞ control. Finally, simulation based on double closed-loop PI (Proportion Integration control system indicates that the proposed method is effective for compensating unknown time-varying delay. Tracking experiments on the opto-electronic platform indicate that RMS (root-mean-square error is 1.253 mrad when tracking 10° 0.2 Hz signal.

  17. Autonomous Cargo Transport System for an Unmanned Aerial Vehicle, using Visual Servoing

    Directory of Open Access Journals (Sweden)

    Noah Kuntz

    2009-12-01

    Full Text Available This paper presents the design and testing of a system for autonomous tracking, pickup, and delivery of cargo via an unmanned helicopter. The tracking system uses a visual servoing algorithm and is tested using open loop velocity control of a six degree of freedom gantry system with a camera mounted via a pan-tilt unit on the end effecter. The pickup system uses vision to direct the camera pan tilt unit to track the target, and uses a hook attached to a second pan tilt unit to pick up the cargo. The ability of the pickup system to hook a target is tested by mounting it on the Systems Integrated Sensor Test Rig gantry system while recorded helicopter velocities are played back by the test rig.

  18. The Improved SVM Multi Objects' Identification For the Uncalibrated Visual Servoing

    Directory of Open Access Journals (Sweden)

    Min Wang

    2009-03-01

    Full Text Available For the assembly of multi micro objects in micromanipulation, the first task is to identify multi micro parts. We present an improved support vector machine algorithm, which employs invariant moments based edge extraction to obtain feature attribute and then presents a heuristic attribute reduction algorithm based on rough set's discernibility matrix to obtain attribute reduction, with using support vector machine to identify and classify the targets. The visual servoing is the second task. For avoiding the complicated calibration of intrinsic parameter of camera, We apply an improved broyden's method to estimate the image jacobian matrix online, which employs chebyshev polynomial to construct a cost function to approximate the optimization value, obtaining a fast convergence for online estimation. Last, a two DOF visual controller based fuzzy adaptive PD control law for micro-manipulation is presented. The experiments of micro-assembly of micro parts in microscopes confirm that the proposed methods are effective and feasible.

  19. The Improved SVM Multi Objects's Identification for the Uncalibrated Visual Servoing

    Directory of Open Access Journals (Sweden)

    Xiangjin Zeng

    2009-03-01

    Full Text Available For the assembly of multi micro objects in micromanipulation, the first task is to identify multi micro parts. We present an improved support vector machine algorithm, which employs invariant moments based edge extraction to obtain feature attribute and then presents a heuristic attribute reduction algorithm based on rough set's discernibility matrix to obtain attribute reduction, with using support vector machine to identify and classify the targets. The visual servoing is the second task. For avoiding the complicated calibration of intrinsic parameter of camera, We apply an improved broyden's method to estimate the image jacobian matrix online, which employs chebyshev polynomial to construct a cost function to approximate the optimization value, obtaining a fast convergence for online estimation. Last, a two DOF visual controller based fuzzy adaptive PD control law for micro-manipulation is presented. The experiments of micro-assembly of micro parts in microscopes confirm that the proposed methods are effective and feasible.

  20. Improved servo-controlled inertial clock for laboratory tests of general relativity

    International Nuclear Information System (INIS)

    Leyh, C.H.

    1984-01-01

    An inertial clock, consisting of a protected macroscopic rotor as the time base, was developed and tested preliminarily and partially by Cheung. This research offers considerable refinement of the equipment and the operating software, and includes serious testing of the experimental behavior. The inertial clock uses magnetic suspension to levitate a capped hollow cylindrical rotor (called the shroud rotor) within a vacuum chamber. A second rotor (called the proof rotor) is magnetically suspended within the shroud rotor. The shroud rotor is caused to corotate precisely with the rotating proof rotor by a microcomputer-controlled eddy current drive feedback servo loop. This produces a drag-free environment for the proof rotor which becomes the inertial timekeeper. In this way corotation effectively eliminates the residual gas drag on the proof rotor and the magnetic suspension bearing reduces bearing drag

  1. State feedback integral control for a rotary direct drive servo valve using a Lyapunov function approach.

    Science.gov (United States)

    Yu, Jue; Zhuang, Jian; Yu, Dehong

    2015-01-01

    This paper concerns a state feedback integral control using a Lyapunov function approach for a rotary direct drive servo valve (RDDV) while considering parameter uncertainties. Modeling of this RDDV servovalve reveals that its mechanical performance is deeply influenced by friction torques and flow torques; however, these torques are uncertain and mutable due to the nature of fluid flow. To eliminate load resistance and to achieve satisfactory position responses, this paper develops a state feedback control that integrates an integral action and a Lyapunov function. The integral action is introduced to address the nonzero steady-state error; in particular, the Lyapunov function is employed to improve control robustness by adjusting the varying parameters within their value ranges. This new controller also has the advantages of simple structure and ease of implementation. Simulation and experimental results demonstrate that the proposed controller can achieve higher control accuracy and stronger robustness. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  2. Predictive IP controller for robust position control of linear servo system.

    Science.gov (United States)

    Lu, Shaowu; Zhou, Fengxing; Ma, Yajie; Tang, Xiaoqi

    2016-07-01

    Position control is a typical application of linear servo system. In this paper, to reduce the system overshoot, an integral plus proportional (IP) controller is used in the position control implementation. To further improve the control performance, a gain-tuning IP controller based on a generalized predictive control (GPC) law is proposed. Firstly, to represent the dynamics of the position loop, a second-order linear model is used and its model parameters are estimated on-line by using a recursive least squares method. Secondly, based on the GPC law, an optimal control sequence is obtained by using receding horizon, then directly supplies the IP controller with the corresponding control parameters in the real operations. Finally, simulation and experimental results are presented to show the efficiency of proposed scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  3. A new linearized equation for servo valve in hydraulic control systems

    International Nuclear Information System (INIS)

    Kim, Tae Hyung; Lee, Ill Yeong

    2002-01-01

    In the procedure of the hydraulic control system analysis, a linearized approximate equation described by the first order term of Taylor's series has been widely used. Such a linearized equation is effective just near the operating point. And, as of now, there are no general standards on how to determine the operating point of a servo valve in the process of applying the linearized equation. So, in this study, a new linearized equation for valve characteristics is proposed as a modified form of the existing linearized equation. And, a method for selecting an optimal operating point is proposed for the new linearized equation. The effectiveness of the new linearized equation is confirmed through numerical simulations and experiments for a model hydraulic control system

  4. What is the Optimal Strategy for Adaptive Servo-Ventilation Therapy?

    Science.gov (United States)

    Imamura, Teruhiko; Kinugawa, Koichiro

    2018-05-23

    Clinical advantages in the adaptive servo-ventilation (ASV) therapy have been reported in selected heart failure patients with/without sleep-disorder breathing, whereas multicenter randomized control trials could not demonstrate such advantages. Considering this discrepancy, optimal patient selection and device setting may be a key for the successful ASV therapy. Hemodynamic and echocardiographic parameters indicating pulmonary congestion such as elevated pulmonary capillary wedge pressure were reported as predictors of good response to ASV therapy. Recently, parameters indicating right ventricular dysfunction also have been reported as good predictors. Optimal device setting with appropriate pressure setting during appropriate time may also be a key. Large-scale prospective trial with optimal patient selection and optimal device setting is warranted.

  5. A switched energy saving position controller for variable-pressure electro-hydraulic servo systems.

    Science.gov (United States)

    Tivay, Ali; Zareinejad, Mohammad; Rezaei, S Mehdi; Baghestan, Keivan

    2014-07-01

    The electro-hydraulic servo system (EHSS) demonstrates a relatively low level of efficiency compared to other available actuation methods. The objective of this paper is to increase this efficiency by introducing a variable supply pressure into the system and controlling this pressure during the task of position tracking. For this purpose, an EHSS structure with controllable supply pressure is proposed and its dynamic model is derived from the basic laws of physics. A switching control structure is then proposed to control both the supply pressure and the cylinder position at the same time, in a way that reduces the overall energy consumption of the system. The stability of the proposed switching control system is guaranteed by proof, and its performance is verified by experimental testing. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  6. Visual Servoing Tracking Control of a Ball and Plate System: Design, Implementation and Experimental Validation

    Directory of Open Access Journals (Sweden)

    Ming-Tzu Ho

    2013-07-01

    Full Text Available This paper presents the design, implementation and validation of real-time visual servoing tracking control for a ball and plate system. The position of the ball is measured with a machine vision system. The image processing algorithms of the machine vision system are pipelined and implemented on a field programmable gate array (FPGA device to meet real-time constraints. A detailed dynamic model of the system is derived for the simulation study. By neglecting the high-order coupling terms, the ball and plate system model is simplified into two decoupled ball and beam systems, and an approximate input-output feedback linearization approach is then used to design the controller for trajectory tracking. The designed control law is implemented on a digital signal processor (DSP. The validity of the performance of the developed control system is investigated through simulation and experimental studies. Experimental results show that the designed system functions well with reasonable agreement with simulations.

  7. Incremental inverse kinematics based vision servo for autonomous robotic capture of non-cooperative space debris

    Science.gov (United States)

    Dong, Gangqi; Zhu, Z. H.

    2016-04-01

    This paper proposed a new incremental inverse kinematics based vision servo approach for robotic manipulators to capture a non-cooperative target autonomously. The target's pose and motion are estimated by a vision system using integrated photogrammetry and EKF algorithm. Based on the estimated pose and motion of the target, the instantaneous desired position of the end-effector is predicted by inverse kinematics and the robotic manipulator is moved incrementally from its current configuration subject to the joint speed limits. This approach effectively eliminates the multiple solutions in the inverse kinematics and increases the robustness of the control algorithm. The proposed approach is validated by a hardware-in-the-loop simulation, where the pose and motion of the non-cooperative target is estimated by a real vision system. The simulation results demonstrate the effectiveness and robustness of the proposed estimation approach for the target and the incremental control strategy for the robotic manipulator.

  8. Application of simple adaptive control to water hydraulic servo cylinder system

    Science.gov (United States)

    Ito, Kazuhisa; Yamada, Tsuyoshi; Ikeo, Shigeru; Takahashi, Koji

    2012-09-01

    Although conventional model reference adaptive control (MRAC) achieves good tracking performance for cylinder control, the controller structure is much more complicated and has less robustness to disturbance in real applications. This paper discusses the use of simple adaptive control (SAC) for positioning a water hydraulic servo cylinder system. Compared with MRAC, SAC has a simpler and lower order structure, i.e., higher feasibility. The control performance of SAC is examined and evaluated on a water hydraulic servo cylinder system. With the recent increased concerns over global environmental problems, the water hydraulic technique using pure tap water as a pressure medium has become a new drive source comparable to electric, oil hydraulic, and pneumatic drive systems. This technique is also preferred because of its high power density, high safety against fire hazards in production plants, and easy availability. However, the main problems for precise control in a water hydraulic system are steady state errors and overshoot due to its large friction torque and considerable leakage flow. MRAC has been already applied to compensate for these effects, and better control performances have been obtained. However, there have been no reports on the application of SAC for water hydraulics. To make clear the merits of SAC, the tracking control performance and robustness are discussed based on experimental results. SAC is confirmed to give better tracking performance compared with PI control, and a control precision comparable to MRAC (within 10 μm of the reference position) and higher robustness to parameter change, despite the simple controller. The research results ensure a wider application of simple adaptive control in real mechanical systems.

  9. the Cecil John Adams Travelling Fellowship

    African Journals Online (AJOL)

    1994-09-14

    Sep 14, 1994 ... 1886 it boasted a coffee-shop, two chemists and a branch of the Standard Bank. ... him a son in 1898 but the infant died at the age of 6 months. By 1900 Florence ... By this time, he had married Laura Green. She was carrying ...

  10. Por qué todas las cuentas son falsas

    OpenAIRE

    Aerde, Michel van

    1994-01-01

    Los principales criterios para evaluación y decisión, en la sociedad actual, son inspirados por cálculos económicos. Mucho nos preocupamos de cuentas pero muy poco nos preguntamos de lo que es el dinero. Muy poco reflexionamos filosóficamente, ontológicamente, sobre la naturaleza misma del dinero. ¿Qué es esto que pretende ser la base de nuestra sociedad? El dinero es mentiroso por naturaleza. Es una representación de mucha vida, que no puede ser representada. El dinero es peligroso, se convi...

  11. Cryptorchidism and hypospadias in sons of gardeners and farmers

    DEFF Research Database (Denmark)

    Weidner, I S; Møller, H; Jensen, Tina Kold

    1998-01-01

    Cryptorchidism and hypospadias have been related to prenatal estrogen exposure in animal models. Some chemicals used in farming and gardening have been shown to possess estrogenic and other hormone-disrupting effects. Earlier studies have indicated increased risks of urogenital malformations...... in the sons of pesticide appliers. In the present study, parental occupation in the farming and gardening industry among 6,177 cases of cryptorchidism, 1,345 cases of hypospadias, and 23,273 controls, born live from 1983 to 1992 in Denmark, was investigated in a register-based case-control study...... of female gardeners could suggest an association with prenatal exposure to occupationally related chemicals....

  12. John Holt Stanway: Gone to Texas

    Science.gov (United States)

    Bryan, J.

    2008-01-01

    John Holt Stanway (1799Ð1872) was an amateur astronomer who lived in Manchester, England until 1845. He was in contact with the English Ôgrand amateurÕ astronomer, William Henry Smyth, who supported him for Fellowship of the Royal Astronomical Society and evidently advised him on how to build and equip an observatory. Apparently, Stanway had an observatory at Chorlton-cum-Hardy in 1837. In 1845, Stanway left for the United States in response to serious business problems. En route, he met Ashbel Smith, a representative of the government of the Republic of Texas, who convinced Stanway to go to Texas. There he changed his name to John H. Smythe Stanley and settled in Houston, where he re-established his observatory. He became a commercial photographer and wrote about astronomy and other scientific subjects in Houston newspapers until his death in 1872.

  13. In Memoriam: Dr. Frank John Fenner

    Centers for Disease Control (CDC) Podcasts

    2011-04-22

    This podcast reflects on one of the greatest pioneers in virology, Dr. Frank John Fenner. Dr. Frederick Murphy, a member of EID's editorial board and the Institute of Medicine, and professor of Pathology at the University of Texas Medical Branch in Galveston, shares professional and personal stories of Dr. Frank Fenner.  Created: 4/22/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 4/26/2011.

  14. 65 Year Birthday Celebration's Prof. John Ellis.

    CERN Multimedia

    Benoit Jeannet

    2011-01-01

    On 13 September, physicists from around the world joined John Ellis at a colloquium to celebrate his 65th birthday, and as he ended his long career as a distinguished CERN staff member and joins King’s College London. Here he is in the audience with fellow theorists, Nobel laureate Gerard ’t Hooft and Chris Llewellyn Smith, former director-general of CERN.

  15. John Dewey's Visits to Hawai'i

    Science.gov (United States)

    McEwan, Hunter

    2015-01-01

    John Dewey visited Hawai'i on three separate occasions. Of all three trips, by far the most important, as far as Dewey's influence on education in Hawai'i is concerned, was in 1899 when he came with his wife, Alice Chipman Dewey, to help launch the University Extension program in Honolulu. The Deweys' second trip was a very brief one--twenty years…

  16. Historical Footage of John Glenn Friendship 7

    Science.gov (United States)

    1962-01-01

    The Friendship mission launch on the 20th day of February marked the first time that an American attempts to orbit the Earth. Historical footage of John Glenn's suit up, ride out to the launch pad, countdown, liftoff, booster engine cutoff, and separation of the booster engine escape tower is shown. Views of the Earth, Glenn's manual control of the electrical fly-by wire system, and the recovery of the landing vehicle from the ocean are presented.

  17. Like father, like son: the intergenerational cycle of adolescent fatherhood.

    Science.gov (United States)

    Sipsma, Heather; Biello, Katie Brooks; Cole-Lewis, Heather; Kershaw, Trace

    2010-03-01

    Strong evidence exists to support an intergenerational cycle of adolescent fatherhood, yet such a cycle has not been studied. We examined whether paternal adolescent fatherhood (i.e., father of study participant was age 19 years or younger when his first child was born) and other factors derived from the ecological systems theory predicted participant adolescent fatherhood. Data included 1496 young males who were interviewed annually from the National Longitudinal Survey of Youth 1997. Cox regression survival analysis was used to determine the effect of paternal adolescent fatherhood on participant adolescent fatherhood. Sons of adolescent fathers were 1.8 times more likely to become adolescent fathers than were sons of older fathers, after other risk factors were accounted for. Additionally, factors from each ecological domain-individual (delinquency), family (maternal education), peer (early adolescent dating), and environment (race/ethnicity, physical risk environment)-were independent predictors of adolescent fatherhood. These findings support the need for pregnancy prevention interventions specifically designed for young males who may be at high risk for continuing this cycle. Interventions that address multiple levels of risk will likely be most successful at reducing pregnancies among partners of young men.

  18. Sexy sons: a dead end for cytoplasmic genes.

    Science.gov (United States)

    Zeh, Jeanne A

    2004-08-07

    Critics of sexual conflict theory argue that females may gain a net reproductive benefit from mating with manipulative males because the direct costs that they suffer may be offset by the production of sexy, i.e. manipulative, sons. However, this exclusive focus on nuclear gene effects represents an incomplete view of female fitness. Females differ fundamentally from males in transmitting not only nuclear genes but also a wide range of cytoplasmic genetic elements (CGEs) that can have profound effects, from male killing to influencing development of the nervous system and cognitive ability. Maternal transmission of CGEs has two major implications for sexual selection. First, the evolution of male fitness traits, such as sperm competitive ability, may be constrained because response to selection on mitochondrial genomes can occur only through the female line. Second, CGEs bear the direct costs of male manipulation but gain no indirect benefits when females produce sexy sons. This should result in perpetual antagonistic coevolution between nuclear genes involved in male manipulation and CGEs that promote female resistance to male sexually selected traits. Explicit consideration of the consequences of selection acting on CGEs is therefore necessary for a better understanding of the relationship between sexual selection and sexual conflict.

  19. Obituary: John P. Oliver (1939-2011)

    Science.gov (United States)

    Cohen, Howard

    2011-12-01

    John P. Oliver, an emeritus professor of astronomy at the University of Florida in Gainesville, passed away Thursday, February 10, 2011, after a courageous and long battle with renal cancer. He left behind memories of a life and career to envy. During his forty years of service to his profession and department, this unique astronomer distinguished himself as a research scientist and instrumentalist, creative software designer, gifted teacher and speaker, a vocal advocate of public outreach, and friend to all who knew him. Oliver was born in New Rochelle, New York, during late fall 1939 on November 24. His father, James P. Oliver, was a naval officer and his mother was the former Dorothy Armstrong Cambell. Oliver's early days were spent in various cities due to his father's military life but he eventually received a high school diploma from Princess Ann High School in Virginia. Oliver subsequently graduated with a bachelor of science degree in physics in 1963 from the prestigious Rensselaer Polytechnic Institute in Troy. Lick Observatory awarded him a graduate assistantship so he moved west to California where he met and, on November 2, 1963, married Barbara Kay McKenna, who became his lifelong love and partner. In California Oliver had the good fortune to work with several eminent astronomers. This included Albert E. Whifford, director of Lick Observatory and known for his work on interstellar reddening, and Merle F. Walker, an expert in photometry, who also helped establish Pluto's rotation period. His close relation with Lawrence H. Aller, one of the 20th century's memorable astronomers, known for his ability to combine observation, theory and education, and for his care and kindness, helped bind Oliver and astronomy together for life. Oliver would also join the technical staff of the Aerospace Corporation, become an acting director of the Pine Mountain Observatory (University of Oregon), and a research assistant at the University of California in Los Angeles

  20. Obituary: John Beverley Oke, 1928-2004

    Science.gov (United States)

    Hesser, James Edward

    2004-12-01

    John Beverley (Bev) Oke passed away of heart failure early on 2 March 2004 at his Victoria, B.C. home. Bev's insatiable scientific curiosity led to fundamental contributions in many areas of stellar and extragalactic astronomy, including the development of advanced instrumentation for the largest optical telescopes and the mentoring of scores of grateful students and colleagues. Bev Oke was born in Sault Ste. Marie, ON, Canada on 23 March 1928, the son of Lyla Parteshuk and the Rev. C. Clare Oke. He entered the University of Toronto in 1945 to study physics with a steadily increasing fraction of astronomy, receiving his BA in 1949. Summer employment at the David Dunlap Observatory (DDO, 1948) and at the Dominion Observatory (Ottawa, 1949, 1950) sealed his interest in astronomy as a career. For his MA thesis (1950, Toronto), performed under theoretician Ralph Williamson, he made interior models of the Sun, and was proud to have proved that the proton-proton cycle was indeed the source of solar energy. Upon entering Princeton University he worked with Martin Schwarzschild on stellar interiors models and Lyman Spitzer on interstellar lines. A lifelong friendship with Alan Sandage began during Bev's second year while Alan was a post-doc at Princeton. During Bev's third year he spent three months in Pasadena with Lyman obtaining data for his thesis on Of stars. While in Pasadena he began a second life-long collaboration with Jesse Greenstein, an astronomer whose approach to science Bev deeply respected. In the small field of astronomy in that era, Bev wrote to DDO Director Jack Heard indicating the nearing completion of his PhD studies and his interest in a position. This led to a lectureship at the University of Toronto (1953-1956), followed by an Assistant Professorship (1956-1958). Bev's interest in instruments began at this time, when he built a device to convert photographic density to intensity, and worked with DDO engineer-machinist Jerry Longworth to implement

  1. Islamic Architecture as a Field of Historical Enquiry, AD Architectural Design, 74(6, 2004 Reproduced by courtesy of the publishers John Wiley & Sons Ltd.

    Directory of Open Access Journals (Sweden)

    Nasser Rabbat

    2012-12-01

    Full Text Available Islamic architecture, a young field with a conservative scholarly lineage, has only recently begun to find its own theoretical bearings. After briefly reviewing the origins and formative stages of the field in the West, this article identifies a turning point brought about by the publication of Edward Saïd's seminal book Orientalism in 1978. It then introduces three critical notions, dynamic periodization, multiculturalism, and dialogue, which offer a framework for the study of Islamic architecture as a tradition with a solid historical selfconsciousness.

  2. Meaning of becoming mother and son/daughter through massage

    Directory of Open Access Journals (Sweden)

    Francisca Márquez Doren

    2014-06-01

    Full Text Available Objective: Revealing the experience of mothers when massaging their children to know the phenomenon in the context of a mother-child healthy development. Method: This is a qualitative study with a phenomenological approach carried out with 11 women who massaged their children and answered the guiding question: What did the experience of massaging your child mean to you? Results: The experience of massaging their children meant the development of their being a mother and of being a son/daughter, in addition to developing the attachment relationship between them. The massage can operationalize this integrality, become a tool of communication, stimulation and promotion of secure attachment, by promoting the loving interaction between mother and child. Conclusion: This practice should be considered as an option in the programs that promote the comprehensive health of the mother and child.

  3. iSERVO: Implementing the International Solid Earth Research Virtual Observatory by Integrating Computational Grid and Geographical Information Web Services

    Science.gov (United States)

    Aktas, Mehmet; Aydin, Galip; Donnellan, Andrea; Fox, Geoffrey; Granat, Robert; Grant, Lisa; Lyzenga, Greg; McLeod, Dennis; Pallickara, Shrideep; Parker, Jay; Pierce, Marlon; Rundle, John; Sayar, Ahmet; Tullis, Terry

    2006-12-01

    We describe the goals and initial implementation of the International Solid Earth Virtual Observatory (iSERVO). This system is built using a Web Services approach to Grid computing infrastructure and is accessed via a component-based Web portal user interface. We describe our implementations of services used by this system, including Geographical Information System (GIS)-based data grid services for accessing remote data repositories and job management services for controlling multiple execution steps. iSERVO is an example of a larger trend to build globally scalable scientific computing infrastructures using the Service Oriented Architecture approach. Adoption of this approach raises a number of research challenges in millisecond-latency message systems suitable for internet-enabled scientific applications. We review our research in these areas.

  4. Numerical calculation of three-dimensional flow field of servo-piston hydraulic control rod driving mechanism

    International Nuclear Information System (INIS)

    Yu Mingrui; Han Weishi; Wang Ge

    2014-01-01

    Servo-piston hydraulic control rod driving mechanism is a new type built-in driving mechanism which is suitable for integrated reactor and it can be moved continuously. The numerical calculation and analysis of the internal three-dimensional flow field inside the driving mechanism were carried out by the computational fluid dynamics software FLUENT. The result shows that the unique pressure mutation area of flow field inside the driving mechanism is at the place of the servo variable throttle orifice. The differential pressure of the piston can be effectively controlled by changing the gap of variable throttle orifice. When the gap changes within 0.5 mm, the differential pressure can be greatly changed, and then the driving mechanism motion state would be changed too. When the working pressure is 0.1 MPa, the hoisting capacity of the driving mechanism can meet the design requirements, and the flow rate is small. (authors)

  5. Robust and Stable Disturbance Observer of Servo System for Low Speed Operation Using the Radial Basis Function Network

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2005-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low speed operation is sensitive to the variation of machine parameter, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable...... in the sense of Lyapunov. The effectiveness of the proposed inertia estimation is verified by simulations and experiments. It is concluded that the speed control performance in low speed region is improved with the proposed disturbance observer using RBFN....

  6. Measuring the photodetector frequency response for ultrasonic applications by a heterodyne system with difference- frequency servo control.

    Science.gov (United States)

    Koch, Christian

    2010-05-01

    A technique for the calibration of photodiodes in ultrasonic measurement systems using standard and cost-effective optical and electronic components is presented. A heterodyne system was realized using two commercially available distributed feedback lasers, and the required frequency stability and resolution were ensured by a difference-frequency servo control scheme. The frequency-sensitive element generating the error signal for the servo loop comprised a delay-line discriminator constructed from electronic elements. Measurements were carried out at up to 450 MHz, and the uncertainties of about 5% (k = 2) can be further reduced by improved radio frequency power measurement without losing the feature of using only simple elements. The technique initially dedicated to the determination of the frequency response of photodetectors applied in ultrasonic applications can be transferred to other application fields of optical measurements.

  7. Forward Models Applied in Visual Servoing for a Reaching Task in the iCub Humanoid Robot

    Directory of Open Access Journals (Sweden)

    Daniel Fernando Tello Gamarra

    2009-01-01

    Full Text Available This paper details the application of a forward model to improve a reaching task. The reaching task must be accomplished by a humanoid robot with 53 degrees of freedom (d.o.f. and a stereo-vision system. We have explored via simulations a new way of constructing and utilizing a forward model that encodes eye–hand relationships. We constructed a forward model using the data obtained from only a single reaching attempt. ANFIS neural networks are used to construct the forward model, but the forward model is updated online with new information that comes from each reaching attempt. Using the obtained forward model, an initial image Jacobian is estimated and is used with a visual servoing controller. Simulation results demonstrate that errors are lower when the initial image Jacobian is derived from the forward model. This paper is one of the few attempts at applying visual servoing in a complete humanoid robot.

  8. Transgenerational effects of nutrition are different for sons and daughters.

    Science.gov (United States)

    Zizzari, Z V; van Straalen, N M; Ellers, J

    2016-07-01

    Food shortage is an important selective factor shaping animal life-history trajectories. Yet, despite its role, many aspects of the interaction between parental and offspring food environments remain unclear. In this study, we measured developmental plasticity in response to food availability over two generations and tested the relative contribution of paternal and maternal food availability to the performance of offspring reared under matched and mismatched food environments. We applied a cross-generational split-brood design using the springtail Orchesella cincta, which is found in the litter layer of temperate forests. The results show adverse effects of food limitation on several life-history traits and reproductive performance of both parental sexes. Food conditions of both parents contributed to the offspring phenotypic variation, providing evidence for transgenerational effects of diet. Parental diet influenced sons' age at maturity and daughters' weight at maturity. Specifically, being born to food-restricted parents allowed offspring to alleviate the adverse effects of food limitation, without reducing their performance under well-fed conditions. Thus, parents raised on a poor diet primed their offspring for a more efficient resource use. However, a mismatch between maternal and offspring food environments generated sex-specific adverse effects: female offspring born to well-fed mothers showed a decreased flexibility to deal with low-food conditions. Notably, these maternal effects of food availability were not observed in the sons. Finally, we found that the relationship between age and size at maturity differed between males and females and showed that offspring life-history strategies in O. cincta are primed differently by the parents. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  9. Les Ilenti ou maudire son prochain en turc

    Directory of Open Access Journals (Sweden)

    Altan Gokalp

    2009-05-01

    Full Text Available La langue turque contemporaine dispopse d’un nombre important de formules d’invective et de malédiction qui relèvent d’un genre appelé ilenç ou ilenti, forme qui est connue depuis les premières inscriptions turques runiques de la Haute Asie. Bien que l’islam réprouve le fait de maudire son prochain, le genre issu d’une grande tradition turque ancienne est d’un usage commun chez les Turcs. Plus encore, la manière de maudire relève d’une tradition savante, d’un « Grand Parler » qui s’apparente aux genres littéraires les plus classiques comme l’épopée, le conte ou la poésie lyrique : la métrique, les rimes, l’usage des assonances obéissent aux mêmes règles que la grande tradition littéraire turque. En cela, le fait d’user de l’invective et de la malédiction est d’une certaine manière une prétention à la distinction et à la domination de l’autre. Les cibles de l’invective éclairent bien cette volonté de dominer et de détruire son ennemi (le corps, la famille, la maladie, une mort peu digne, etc..

  10. John Paul College: The Professional Renewal Journey

    Directory of Open Access Journals (Sweden)

    Pauline Mundie

    2014-09-01

    Full Text Available John Paul College, a K-12 School in Queensland, Australia, recognises the centrality of classroom teachers to the ongoing improvement of student outcomes. The college has implemented a multi-tiered professional renewal and assessment process. These changes of emphasis are the result of significant research and subsequent/associated professional discussion and were supported during the EBA decision-making in 2012. The professional renewal process at John Paul College guides teachers through a cycle of goal setting (related to any aspect of teacher practice which aims to improve student learning and achievement; ongoing discussion between the teacher and a mentor which determines actions; directed classroom observations (3 per term and associated pre and post reflection/discussion; leading to application of changed practice toward achieving the criteria of the goals. The principles of the professional renewal program are to:  enhance development along accepted school-wide, team and department goals;  encourage professional pedagogical reflections and conversations with a colleague/mentor;  motivate improved performance and highlight the next steps in a teacher’s development. Through the introduction of professional renewal, attestation and exemplary teacher processes, the leadership and teachers of John Paul College have achieved an appropriate and innovative balance between self-directed, peer supported/directed and college-wide, strategic initiatives. Each member of the teaching team, from graduate to senior leaders are actively engaged in personalised programs of professional growth which is specifically aimed at improved learning and outcomes of the college’s students.

  11. Adaptive-Repetitive Visual-Servo Control of Low-Flying Aerial Robots via Uncalibrated High-Flying Cameras

    Science.gov (United States)

    Guo, Dejun; Bourne, Joseph R.; Wang, Hesheng; Yim, Woosoon; Leang, Kam K.

    2017-08-01

    This paper presents the design and implementation of an adaptive-repetitive visual-servo control system for a moving high-flying vehicle (HFV) with an uncalibrated camera to monitor, track, and precisely control the movements of a low-flying vehicle (LFV) or mobile ground robot. Applications of this control strategy include the use of high-flying unmanned aerial vehicles (UAVs) with computer vision for monitoring, controlling, and coordinating the movements of lower altitude agents in areas, for example, where GPS signals may be unreliable or nonexistent. When deployed, a remote operator of the HFV defines the desired trajectory for the LFV in the HFV's camera frame. Due to the circular motion of the HFV, the resulting motion trajectory of the LFV in the image frame can be periodic in time, thus an adaptive-repetitive control system is exploited for regulation and/or trajectory tracking. The adaptive control law is able to handle uncertainties in the camera's intrinsic and extrinsic parameters. The design and stability analysis of the closed-loop control system is presented, where Lyapunov stability is shown. Simulation and experimental results are presented to demonstrate the effectiveness of the method for controlling the movement of a low-flying quadcopter, demonstrating the capabilities of the visual-servo control system for localization (i.e.,, motion capturing) and trajectory tracking control. In fact, results show that the LFV can be commanded to hover in place as well as track a user-defined flower-shaped closed trajectory, while the HFV and camera system circulates above with constant angular velocity. On average, the proposed adaptive-repetitive visual-servo control system reduces the average RMS tracking error by over 77% in the image plane and over 71% in the world frame compared to using just the adaptive visual-servo control law.

  12. The John Zink Hamworthy combustion handbook

    CERN Document Server

    Baukal, Charles E

    2013-01-01

    Despite the length of time it has been around, its importance, and vast amounts of research, combustion is still far from being completely understood. Issues regarding the environment, cost, and fuel consumption add further complexity, particularly in the process and power generation industries. Dedicated to advancing the art and science of industrial combustion, The John Zink Hamworthy Combustion Handbook, Second Edition: Volume 3 - Applications offers comprehensive, up-to-date coverage of equipment used in the process and power generation industries. Under the leadership of Charles E. Baukal

  13. Suehiro Jurisprudence and John R. Commons

    DEFF Research Database (Denmark)

    Tackney, Charles T.

    This is a comparative history study at the interface of industrial / employment relations and stakeholder theory. The focus concerns decades of post-World War II Japanese and U.S. path dependent national divergence from common labor legislation enactments separated by only 15 years: 1933...... or Suehiro hōgaku) document a dramatic, fascinating historical parting of two nations due to Japanese deep appreciation of the labor law and institutional economics research legacy of John R. Commons, the father of U.S. industrial relations. Understanding this common, shared source opens industrial relations...

  14. Part Twelve. The Voyages of John Matthias

    OpenAIRE

    Printz-Påhlson, Göran

    2013-01-01

    In August 1974, when the Watergate scandal was moving into its last phase, the American poet John Matthias returned to his home, in South Bend, Indiana, after a year’s stay in England, traveling on the Polish ocean-liner Stefan Bathory. In June of 1976 he set out to sea again, this time on a Russian ship, the Mikhail Lermontov, in order to spend another year in England, as a Visiting Fellow in Poetry in Clare Hall, Cambridge. The voyages took approximately nine days each, and on both ships he...

  15. John Locke on persons and personal identity

    OpenAIRE

    Boeker, Ruth

    2013-01-01

    John Locke claims both that ‘person’ is a forensic term and that personal identity consists in sameness of consciousness. The aim of my dissertation is to explain and critically assess how Locke links his moral and legal account of personhood to his account of personal identity in terms of sameness of consciousness. My interpretation of Locke’s account of persons and personal identity is embedded in Locke’s sortal-dependent account of identity. Locke’s sortal-dependent ac...

  16. Remembering John M. Olson (1929-2017).

    Science.gov (United States)

    Blankenship, Robert E; Brune, Daniel C; Olson, Jon C

    2018-02-19

    Here we provide reflections of and a tribute to John M. Olson, a pioneering researcher in photosynthesis. We trace his career, which began at Wesleyan University and the University of Pennsylvania, and continued at Utrech in The Netherlands, Brookhaven National Laboratory, and Odense University in Denmark. He was the world expert on pigment organization in the green photosynthetic bacteria, and discovered and characterized the first chlorophyll-containing protein, which has come to be known as the Fenna-Matthews-Olson (FMO) protein. He also thought and wrote extensively on the origin and early evolution of photosynthesis. We include personal comments from Brian Matthews, Raymond Cox, Paolo Gerola, Beverly Pierson and Jon Olson.

  17. A Study on the Air Vent Valve of the Hydraulic Servo Actuator for Steam Control of Power Plants

    International Nuclear Information System (INIS)

    Lee, Yong Bum; Lee, Jong Jik

    2016-01-01

    To produce adequate electricity in nuclear and thermal power plants, an optimal amount of steam should be supplied to a generator connected to high- and low-pressure steam turbines. A turbine output control device, which is a special steam valve employed to supply or interrupt the steam to the turbine, is operated using a hydraulic servo actuator. In power plants, the performance of servo actuators is degraded by the air generated from the hydraulic system, or causes frequent failures owing to an increase in the wear of the seal. This is due to the seal being burnt as generated heat using the produced compressed air. Some power plants have exhausted air using a fixed orifice, and thus they encounter power loss due to mass flow exhaust. Failures are generated in hydraulic pumps, electric motors, and valves, which are frequently operated. In this study, we perform modeling and analysis of the load-sensing air-exhaust valves, which can be passed through very fine flow under normal use conditions, and exhaust mass flow air at the beginning stage as with existing fixed orifices. Then, we propose a method to prevent failures due to the compressed air, and to ensure the control accuracy of hydraulic servo actuators.

  18. Turbofan Volume Dynamics Model for Investigations of Aero-Propulso-Servo-Elastic Effects in a Supersonic Commercial Transport

    Science.gov (United States)

    Connolly, Joseph W.; Kopasakis, George; Lemon, Kimberly A.

    2010-01-01

    A turbofan simulation has been developed for use in aero-propulso-servo-elastic coupling studies, on supersonic vehicles. A one-dimensional lumped volume approach is used whereby each component (fan, high-pressure compressor, combustor, etc.) is represented as a single volume using characteristic performance maps and conservation equations for continuity, momentum and energy. The simulation is developed in the MATLAB/SIMULINK (The MathWorks, Inc.) environment in order to facilitate controls development, and ease of integration with a future aero-servo-elastic vehicle model being developed at NASA Langley. The complete simulation demonstrated steady state results that closely match a proposed engine suitable for a supersonic business jet at the cruise condition. Preliminary investigation of the transient simulation revealed expected trends for fuel flow disturbances as well as upstream pressure disturbances. A framework for system identification enables development of linear models for controller design. Utilizing this framework, a transfer function modeling an upstream pressure disturbance s impacts on the engine speed is developed as an illustrative case of the system identification. This work will eventually enable an overall vehicle aero-propulso-servo-elastic model

  19. Bi-level positive pressure ventilation and adaptive servo ventilation in patients with heart failure and Cheyne-Stokes respiration.

    Science.gov (United States)

    Fietze, Ingo; Blau, Alexander; Glos, Martin; Theres, Heinz; Baumann, Gert; Penzel, Thomas

    2008-08-01

    Nocturnal positive pressure ventilation (PPV) has been shown to be effective in patients with impaired left ventricular ejection fraction (LVEF) and Cheyne-Stokes respiration (CSR). We investigated the effect of a bi-level PPV and adaptive servo ventilation on LVEF, CSR, and quantitative sleep quality. Thirty-seven patients (New York heart association [NYHA] II-III) with LVEFCSR were investigated by electrocardiography (ECG), echocardiography and polysomnography. The CSR index (CSRI) was 32.3+/-16.2/h. Patients were randomly treated with bi-level PPV using the standard spontaneous/timed (S/T) mode or with adaptive servo ventilation mode (AutoSetCS). After 6 weeks, 30 patients underwent control investigations with ECG, echocardiography, and polysomnography. The CSRI decreased significantly to 13.6+/-13.4/h. LVEF increased significantly after 6 weeks of ventilation (from 25.1+/-8.5 to 28.8+/-9.8%, plevel PPV and adaptive servo ventilation: the CSRI decreased more in the AutoSetCS group while the LVEF increased more in the bi-level PPV group. Administration of PPV can successfully attenuate CSA. Reduced CSA may be associated with improved LVEF; however, this may depend on the mode of PPV. Changed LVEF is evident even in the absence of significant changes in blood pressure.

  20. Real Time Implementation of PID and Fuzzy PD Controllers for DC-Servo Motor Based on Lab View Environment

    Directory of Open Access Journals (Sweden)

    Safaa M. Z. Al-Ubaidi

    2012-06-01

    Full Text Available This paper presents an implementation of conventional PID (CPID controller using Ziegler-Nichols rules and fuzzy PD (FPD controller for position servo motor control based on Lab View (Laboratory Virtual Instrument Engineering Workbench Environment through Data Acquisition (DAQ Device PCI- 6521 of National Instrument's and Data Acquisition Accessory Board Model (CB-68LP.CPID controller is perhaps the most well-known and most widely used in industrial applications. However, it has been known that CPID controller generally don’t work well for non-linear systems, higher order and time-delayed linear system and particularly complex and vague system. To overcome these difficulties, this paper proposes to use the FPD controller for a servo motor system instead of CPID. The parameters of servo motor used are completely unknown. The FPD structure has two-input single-output and fairly similar characteristic to its conventional counterpart and provides good performance. Simple rules base are used for FPD (nine rules only. Performance evaluation was carried out via a comparison study for the proposed control scheme and other existing control scheme, such as CPID controller. The critical point for this experiment on position system is a steady state error and settling time.  The performance showing that the FPD has less settling time and zero steady state error over its CPID. The algorithms of FPD and CPID controllers are implemented using PID, Fuzzy Logic and simulation toolkits of the Lab View environment.

  1. A new approach to control of xenon spatial oscillation during load follow operation via robust servo systems

    International Nuclear Information System (INIS)

    Ukai, Hiroyuki; Iwazumi, Tetsuo

    1994-01-01

    The control problem of xenon-induced spatial oscillations of PWR in the axial direction during a load following operation is investigated. The system models are described by a one-group diffusion equation with xenon and temperature feed-backs, iodine and xenon dynamic equations, and heat conductions processes. Control is implemented by the full-length and the part-length control rods and the boron concentration. In order to achieve the control purpose, control models are formulated as the design problem of robust servo systems for distributed parameter reactor systems. The total thermal power and the axial offset are chosen as outputs to be controlled. The control systems consist of servo compensators and stabilizing compensators. They are designed based on the finite-dimensional systems which are constructed by linearizing around steady states, approximately by the Galerkin method, and reducing dimensions via the singular perturbation method. A new and simple computational algorithm to obtain an approximate solution of a steady-state neutron balance is developed via the perturbation method. Some results of numerical simulations are shown in order to discuss the effectiveness of the theory developed in this paper. In particular, it is shown that the designed servo systems are robust against model errors with linearization and modal truncation

  2. A Study on the Air Vent Valve of the Hydraulic Servo Actuator for Steam Control of Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Bum; Lee, Jong Jik [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2016-06-15

    To produce adequate electricity in nuclear and thermal power plants, an optimal amount of steam should be supplied to a generator connected to high- and low-pressure steam turbines. A turbine output control device, which is a special steam valve employed to supply or interrupt the steam to the turbine, is operated using a hydraulic servo actuator. In power plants, the performance of servo actuators is degraded by the air generated from the hydraulic system, or causes frequent failures owing to an increase in the wear of the seal. This is due to the seal being burnt as generated heat using the produced compressed air. Some power plants have exhausted air using a fixed orifice, and thus they encounter power loss due to mass flow exhaust. Failures are generated in hydraulic pumps, electric motors, and valves, which are frequently operated. In this study, we perform modeling and analysis of the load-sensing air-exhaust valves, which can be passed through very fine flow under normal use conditions, and exhaust mass flow air at the beginning stage as with existing fixed orifices. Then, we propose a method to prevent failures due to the compressed air, and to ensure the control accuracy of hydraulic servo actuators.

  3. Steady flow torques in a servo motor operated rotary directional control valve

    International Nuclear Information System (INIS)

    Wang, He; Gong, Guofang; Zhou, Hongbin; Wang, Wei

    2016-01-01

    Highlights: • A novel servo motor operated rotary directional control valve is proposed. • Steady flow torque is a crucial issue that affects rotary valve performance. • Steady flow torque is analyzed on the aspects of theory, simulation and experiment. • Change law of the steady flow torque with spool rotation angle is explored. • Effect of pressure drop and flow rate on the steady flow torque is studied. - Abstract: In this paper, a servo motor operated rotary directional control valve is proposed, and a systematic analysis of steady flow torques in this valve is provided by theoretical calculation, CFD simulation and experimental test. In the analysis, spool rotation angle corresponding to the maximum orifice opening is tagged as 0°. Over a complete change cycle of the orifice, the range of spool rotation angle is symmetric about 0°. The results show that the direction of steady flow torques in this valve is always the direction of orifice closing. The steady flow torques serve as resistances to the spool rotation when the orifice opening increases, while impetuses to the spool rotation when the orifice opening decreases. At a certain pressure drop or flow rate, steady flow torques are approximately equal and opposite when at spool rotation angles which are symmetric about 0°. When the spool rotates from 0°, at a certain pressure drop, their values increase first then decrease with the spool rotation and reach their maximum values at an angle corresponding to about 1/2 of the maximum orifice opening, and at a certain flow rate, their values increase with the spool rotation. The steady flow torques in this valve are the sums of those in the meter-in and meter-out valve chambers. At a certain spool rotation angle, steady flow torques in the meter-in and meter-out valve chambers are approximately proportional to the pressure drop and the second power of the flow rate through the orifice. Theoretical calculation and CFD simulation can be validated by

  4. The Trieste Lecture of John Stewart Bell

    International Nuclear Information System (INIS)

    Bassi, Angelo; Ghirardi, GianCarlo

    2007-01-01

    Delivered at Trieste on the occasion of the 25th Anniversary of the International Centre for Theoretical Physics, 2 November 1989. The video of this lecture is available here. Please see the PDF for the transcript of the lecture. General remarks by Angelo Bassi and GianCarlo Ghirardi During the autumn of 1989 the International Centre for Theoretical Physics, Trieste, celebrated the 25th anniversary of its creation. Among the many prestigious speakers, who delivered extremely interesting lectures on that occasion, was the late John Stewart Bell. All lectures have been recorded on tape. We succeeded in getting a copy of John's lecture. In the lecture, many of the arguments that John had lucidly stressed in his writings appear once more, but there are also extremely interesting new remarks which, to our knowledge, have not been presented elsewhere. In particular he decided, as pointed out by the very choice of the title of his lecture, to call attention to the fact that the theory presents two types of difficulties, which Dirac classified as first and second class. The former are those connected with the so-called macro-objectification problem, the latter with the divergences characterizing relativistic quantum field theories. Bell describes the precise position of Dirac on these problems and he stresses appropriately how, contrary to Dirac's hopes, the steps which have led to a partial overcoming of the second class difficulties have not helped in any way whatsoever to overcome those of the first class. He then proceeds to analyse the origin and development of the Dynamical Reduction Program and draws attention to the problems that still affect it, in particular that of a consistent relativistic generalization. When the two meetings Are there quantum jumps? and On the present status of Quantum Mechanics were organized in Trieste and Losinj (Croatia), on 5-10 September 2005, it occurred to us that this lecture, which has never been published, might represent an

  5. MPI Enhancements in John the Ripper

    International Nuclear Information System (INIS)

    Sykes, Edward R; Lin, Michael; Skoczen, Wesley

    2010-01-01

    John the Ripper (JtR) is an open source software package commonly used by system administrators to enforce password policy. JtR is designed to attack (i.e., crack) passwords encrypted in a wide variety of commonly used formats. While parallel implementations of JtR exist, there are several limitations to them. This research reports on two distinct algorithms that enhance this password cracking tool using the Message Passing Interface. The first algorithm is a novel approach that uses numerous processors to crack one password by using an innovative approach to workload distribution. In this algorithm the candidate password is distributed to all participating processors and the word list is divided based on probability so that each processor has the same likelihood of cracking the password while eliminating overlapping operations. The second algorithm developed in this research involves dividing the passwords within a password file equally amongst available processors while ensuring load-balanced and fault-tolerant behavior. This paper describes John the Ripper, the design of these two algorithms and preliminary results. Given the same amount of time, the original JtR can crack 29 passwords, whereas our algorithms 1 and 2 can crack an additional 35 and 45 passwords respectively.

  6. MPI Enhancements in John the Ripper

    Science.gov (United States)

    Sykes, Edward R.; Lin, Michael; Skoczen, Wesley

    2010-11-01

    John the Ripper (JtR) is an open source software package commonly used by system administrators to enforce password policy. JtR is designed to attack (i.e., crack) passwords encrypted in a wide variety of commonly used formats. While parallel implementations of JtR exist, there are several limitations to them. This research reports on two distinct algorithms that enhance this password cracking tool using the Message Passing Interface. The first algorithm is a novel approach that uses numerous processors to crack one password by using an innovative approach to workload distribution. In this algorithm the candidate password is distributed to all participating processors and the word list is divided based on probability so that each processor has the same likelihood of cracking the password while eliminating overlapping operations. The second algorithm developed in this research involves dividing the passwords within a password file equally amongst available processors while ensuring load-balanced and fault-tolerant behavior. This paper describes John the Ripper, the design of these two algorithms and preliminary results. Given the same amount of time, the original JtR can crack 29 passwords, whereas our algorithms 1 and 2 can crack an additional 35 and 45 passwords respectively.

  7. The Trieste Lecture of John Stewart Bell

    Energy Technology Data Exchange (ETDEWEB)

    Bassi, Angelo; Ghirardi, GianCarlo

    2007-03-23

    Delivered at Trieste on the occasion of the 25th Anniversary of the International Centre for Theoretical Physics, 2 November 1989. The video of this lecture is available here. Please see the PDF for the transcript of the lecture. General remarks by Angelo Bassi and GianCarlo Ghirardi During the autumn of 1989 the International Centre for Theoretical Physics, Trieste, celebrated the 25th anniversary of its creation. Among the many prestigious speakers, who delivered extremely interesting lectures on that occasion, was the late John Stewart Bell. All lectures have been recorded on tape. We succeeded in getting a copy of John's lecture. In the lecture, many of the arguments that John had lucidly stressed in his writings appear once more, but there are also extremely interesting new remarks which, to our knowledge, have not been presented elsewhere. In particular he decided, as pointed out by the very choice of the title of his lecture, to call attention to the fact that the theory presents two types of difficulties, which Dirac classified as first and second class. The former are those connected with the so-called macro-objectification problem, the latter with the divergences characterizing relativistic quantum field theories. Bell describes the precise position of Dirac on these problems and he stresses appropriately how, contrary to Dirac's hopes, the steps which have led to a partial overcoming of the second class difficulties have not helped in any way whatsoever to overcome those of the first class. He then proceeds to analyse the origin and development of the Dynamical Reduction Program and draws attention to the problems that still affect it, in particular that of a consistent relativistic generalization. When the two meetings Are there quantum jumps? and On the present status of Quantum Mechanics were organized in Trieste and Losinj (Croatia), on 5-10 September 2005, it occurred to us that this lecture, which has never been published, might represent

  8. John Dewey’s Feminist Legacy

    Directory of Open Access Journals (Sweden)

    Marta Vaamonde Gamo

    2016-07-01

    Full Text Available This article demonstrates how feminism welcomed and was influenced by the pragmatism of John Dewey. While in real terms his impact on European feminism has been minimal, this was not the case in contemporary America. In this article we study both how Dewey’s ideas were received amongst American feminists, as well as certain aspects of his thinking that could be enormously useful in present-day debates between critical and postmodern feminists. We compare the Deweyan and feminist arguments against the traditional dualisms that acted as philosophical support for social inequality, paying particular attention to mind–body dualism, and the consequent undervaluation of physical and emotional wellbeing. We also show that John Dewey’s proposals were, in fact, more radical than those of the feminists of the day. Indeed, democracy has to be understood as a way of life that affects every dimension of experience, and is crucial to the personal and social growth that enables the unjust social inequalities between men and women to be overcome.

  9. BAKUNIN'S SON, A DIALOGIC NOVEL BY SERGIO ATZENI

    Directory of Open Access Journals (Sweden)

    Masina Depperu (Universidade de Lisboa

    2013-10-01

    Full Text Available Bakunin’s Son, a short novel by Sergio Atzeni, is the perfect embodiment of Bakhtin’s theory of the dialogic novel. The author sets his stories and characters - mostly humble outcast defeated people - in his own homeland, Sardinia. The accurately planned structure as an interview to thirty-two people reflects a multifarious reality with its complex rules and mentality expressed through different points of view, languages and ideologies. The protagonist’s story may result contradictory according to the different opinions of people who met him. Also the choice of a hybrid language contributes to create a highly connoted cultural context. In Bakunin’s Son, in fact, the Italian and the Sardinian overlap in a manner that cannot be distinguished or graphically marked, since form and meaning are fused together.Key words: dialogic novel, hybrid language.O filho de Bakunin, um romance polifónico de Sergio AtzeniO romance breve de Sergio Atzeni, O filho de Bakunin, è a perfeita exemplificação da teoria bachtininana do romance polifónico. O autor insere as histórias e as persona gens, geralmente abatidas, pessoas humildes e marginalizadas, na sua terra natal, a Sardenha. A história è estruturada na forma de entrevista a trinta e duas persona gens que com os seus pontos de vista criam una realidade multi-facetada e subjectiva. A vida de Tullio Saba, o protagonista, está narrada às vezes em modo contraditório e, por isso, os factos podem ser divergentes nas opiniões de quem esteve mais ou menos em contacto directo com ele. O uso característico de um instrumento linguístico híbrido, a meio caminho entre o italiano e o sardo, conota não somente o léxico mas também a estruturação inteira do discurso que atinge o efeito final pretendido pelo autor de descrever uma diversa ealidade antropológico-cultural.Palavras chave: romance polifónico, instrumento linguístico híbrido

  10. The global tantalum industry and Sons of Gwalia Ltd

    International Nuclear Information System (INIS)

    Paull, D.

    2002-01-01

    Sons of Gwalia Ltd., in Perth Australia is a long-term supplier of tantalum (Ta), a valuable rare metal with adequate supply. Tantalum is soft and ductile with high melting and boiling points and a low co-efficient of thermal expansion. It has excellent capacity to store and release electrical charge and offers exceptional resistance to corrosion. Its' main use is in consumer electronics such as mobile phones, laptop computers, DVD players, personal video recorders and MP-3 players. For automotive electronics, tantalum is used for air-bags, audio systems, navigation systems, anti-lock break systems and under the hood vehicle management systems. The super alloy is also in demand by the aerospace industry and for turbine blades for power stations. The total demand of Tantalum in 2000 was 5 million lbs. Demand growth has increased steadily since 1993 with perhaps a slight increase in the past 5 years. Resources are estimated at a 125 year supply based on year 2000 production rates. 41 per cent of the world supply of tantalum is obtained from Australia, 13 per cent from Africa, 16 per cent from America, 22 per cent from Asia. The Greenbushes mine in Australia is the world's largest tantalum mine with 80 million lbs Ta, followed by Australia's Wodgina Mine with 50 million lbs Ta. Both mines are expected to be operational for the next 25 years. 12 figs

  11. Jean Alesi and his son Giuliano visited CERN

    CERN Multimedia

    Emma Jones

    2010-01-01

    Jean Alesi, former F1 racing driver, and his kids visited CERN on Monday 1st February 2010. The Bulletin and the Video productions team had the opportunity to meet him. The video interview is transcribed for your convenience. What attracted you to CERN, what was it that made you want to come? We talked at home with the children about places to see close to us, like CERN, where they are seeking to reproduce the origins of the world. These things are so far removed from what we ordinarily think and talk about, that they captured our imagination and made us want to come see for ourselves. We know that your son (Giuliano, 9 years) is interested in what is happening at CERN, so we'd like to ask him: how did he find out about it? Giuliano: I am very interested in the technologies used in laboratories, and the exploration of the Universe. Plus, I wanted to see some of the incredible machines. I enjoyed my visit a lot. I found out about CERN from my mother. She showed me a video that I really liked, so I wanted to...

  12. ¿Son las mujeres una minoría?

    Directory of Open Access Journals (Sweden)

    Osborne, Raquel

    1996-10-01

    Full Text Available Not available.

    El clásico tratamiento de las mujeres como minoría desde la sociología se halla contemporáneamente interrelacionado con las políticas de igualdad tejidas en torno a las mujeres. Pasado y presente, teoría y práctica se unen para mostrar que las teorías no son accidentales ni fortuitas sino que acarrean importantes consecuencias en la acción, pudiendo dar lugar a intervenciones en la vida pública, que es lo que, a mi entender, confiere su sentido a la. sociología y, en particular, a la sociología del género. El título alude a la existencia de un importante desarrollo en sociología de la temática de las minorías, que traemos a colación por cuanto desde muy temprano dicha ciencia refirió este tema a las mujeres, desarrollo que seguiremos en este artículo. La conceptualización de las mujeres como minoría se traducirá, en términos de políticas públicas, en lo que se conoce como medidas de acción o discriminación positiva impulsadas, en lo que a las mujeres atañe, por el movimiento feminista.

  13. State supervision of SONS in the mammographic departments

    International Nuclear Information System (INIS)

    Jursikova, E.; Kodl, O.

    2008-01-01

    State Office for Nuclear Safety has been performed the state supervision over radiation protection at all mammographic centres in the Czech Republic. Inspections are carried out on the basis of requirements of: Act No. 18/1997 Coll., Atomic Act, subsequently amended; Act No. 552/1991 Coll., Supervision Act, subsequently amended; Decree No. 307 /2002 Coll., On radiation protection, as amended by Decree No. 499/2005 Coll. 137 mammography X-ray units have been used actively by 108 independent licensees since 1 September 2008. The mammography screening program started in September 2002. The screening program was carried out at 59 working places last year and already at 66 workplaces with accreditation from 1 up to 3 years this year. The activity of the centres is monitored and inspected continuously (not only by SONS). Inspections at 35 workplaces were carried out last year .The doses are significantly below guidance levels at major part of working places. Most of detected defects were eliminated after inspections. The quality of mammographic workplaces in the Czech Republic has been gradually increased and improved. (authors)

  14. Design and motion control of bioinspired humanoid robot head from servo motors toward artificial muscles

    Science.gov (United States)

    Almubarak, Yara; Tadesse, Yonas

    2017-04-01

    The potential applications of humanoid robots in social environments, motivates researchers to design, and control biomimetic humanoid robots. Generally, people are more interested to interact with robots that have similar attributes and movements to humans. The head is one of most important part of any social robot. Currently, most humanoid heads use electrical motors, pneumatic actuators, and shape memory alloy (SMA) actuators for actuation. Electrical and pneumatic actuators take most of the space and would cause unsmooth motions. SMAs are expensive to use in humanoids. Recently, in many robotic projects, Twisted and Coiled Polymer (TCP) artificial muscles are used as linear actuators which take up little space compared to the motors. In this paper, we will demonstrate the designing process and motion control of a robotic head with TCP muscles. Servo motors and artificial muscles are used for actuating the head motion, which have been controlled by a cost efficient ARM Cortex-M7 based development board. A complete comparison between the two actuators is presented.

  15. A TSR Visual Servoing System Based on a Novel Dynamic Template Matching Method

    Directory of Open Access Journals (Sweden)

    Jia Cai

    2015-12-01

    Full Text Available The so-called Tethered Space Robot (TSR is a novel active space debris removal system. To solve its problem of non-cooperative target recognition during short-distance rendezvous events, this paper presents a framework for a real-time visual servoing system using non-calibrated monocular-CMOS (Complementary Metal Oxide Semiconductor. When a small template is used for matching with a large scene, it always leads to mismatches, so a novel template matching algorithm to solve the problem is presented. Firstly, the novel matching algorithm uses a hollow annulus structure according to a FAST (Features from Accelerated Segment algorithm and makes the method be rotation-invariant. Furthermore, the accumulative deviation can be decreased by the hollow structure. The matching function is composed of grey and gradient differences between template and object image, which help it reduce the effects of illumination and noises. Then, a dynamic template update strategy is designed to avoid tracking failures brought about by wrong matching or occlusion. Finally, the system synthesizes the least square integrated predictor, realizing tracking online in complex circumstances. The results of ground experiments show that the proposed algorithm can decrease the need for sophisticated computation and improves matching accuracy.

  16. A Visual Servoing-Based Method for ProCam Systems Calibration

    Directory of Open Access Journals (Sweden)

    Jeremie Mosnier

    2013-10-01

    Full Text Available Projector-camera systems are currently used in a wide field of applications, such as 3D reconstruction and augmented reality, and can provide accurate measurements, depending on the configuration and calibration. Frequently, the calibration task is divided into two steps: camera calibration followed by projector calibration. The latter still poses certain problems that are not easy to solve, such as the difficulty in obtaining a set of 2D–3D points to compute the projection matrix between the projector and the world. Existing methods are either not sufficiently accurate or not flexible. We propose an easy and automatic method to calibrate such systems that consists in projecting a calibration pattern and superimposing it automatically on a known printed pattern. The projected pattern is provided by a virtual camera observing a virtual pattern in an OpenGL model. The projector displays what the virtual camera visualizes. Thus, the projected pattern can be controlled and superimposed on the printed one with the aid of visual servoing. Our experimental results compare favorably with those of other methods considering both usability and accuracy.

  17. Disturbance torque rejection properties of the NASA/JPL 70-meter antenna axis servos

    Science.gov (United States)

    Hill, R. E.

    1989-01-01

    Analytic methods for evaluating pointing errors caused by external disturbance torques are developed and applied to determine the effects of representative values of wind and friction torque. The expressions relating pointing errors to disturbance torques are shown to be strongly dependent upon the state estimator parameters, as well as upon the state feedback gain and the flow versus pressure characteristics of the hydraulic system. Under certain conditions, when control is derived from an uncorrected estimate of integral position error, the desired type 2 servo properties are not realized and finite steady-state position errors result. Methods for reducing these errors to negligible proportions through the proper selection of control gain and estimator correction parameters are demonstrated. The steady-state error produced by a disturbance torque is found to be directly proportional to the hydraulic internal leakage. This property can be exploited to provide a convenient method of determining system leakage from field measurements of estimator error, axis rate, and hydraulic differential pressure.

  18. Propulsion System Dynamic Modeling for the NASA Supersonic Concept Vehicle: AeroPropulsoServoElasticity

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph; Seidel, Jonathan

    2014-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural-aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report.propulsion system dynamics, the structural dynamics, and aerodynamics.

  19. Application of Automatic Zooming and Autofocusing in Microassembly using Visual Servoing

    International Nuclear Information System (INIS)

    Jang, Kyung-Nam; Kim, Jong-Seog

    2006-01-01

    In recent years, many industrial products and their components are evolving toward miniaturization. To have more functionalities within less dimensional volume, they are usually made of various materials with different characteristics, and they are manufactured using incompatible manufacturing processes with complex geometrical shapes. For these reasons, the assembly technique for mating micro-parts so called microassembly has become important for advanced manufacturing and drawn extensive research interest. Currently, due to various difficulties arising from handling of extremely small size parts, manual assembly method has been widely used. Since this manual method is somehow timeconsuming and not productive enough, automation of micro-assembly has become an essential part for micro parts manufacturing. As an alternative, the vision sensor is widely used in microassembly. The vision sensor has a wide field of view, and it can obtain the wide range data with high speed without contact. In the previous research works, the orientation of the mating parts has not been considered for corrective motion, and, furthermore, the developed vision systems are not adaptive to accommodate various sizes of the mated parts to avoid such criticism, we propose a visual feedback system that accommodates micro parts of various sizes and parts arbitrarily oriented. In this paper, the system that employs adaptive zooming and auto focusing techniques during visual servoing is described

  20. [Development of a gait trainer with regulated servo-drive for rehabilitation of locomotor disabled patients].

    Science.gov (United States)

    Uhlenbrock, D; Sarkodie-Gyan, T; Reiter, F; Konrad, M; Hesse, S

    1997-01-01

    The aim of the present study was to develop a new gait trainer for the rehabilitation of non-ambulatory patients. For the simulation of the gait phase, we used a commercially available fitness trainer (Fast Track) with two foot plates moving in an alternating fashion and connected to a servo-controlled propulsion system providing the necessary support for the movement depending on the patient's impairment level. To compensate deficient equilibrium reflexes, the patient was suspended in a harness capable of supporting some of his/her weight. Video analysis of gait and the kinesiological EMG were used to assess the pattern of movement and the corresponding muscle activity, which were then evaluated in healthy subjects, spinal cord injured and stroke patients and compared with walking on the flat or on a treadmill. Walking on the gait trainer was characterised by a symmetrical, sinusoidal movement of lower amplitude than in normal gait. The EMG showed a low activity of the tibialis anterior muscle, while the antigravity muscles were clearly activated by the gait trainer during the stance phase. In summary, the new gait trainer generates a symmetrical gait-like movement, promoting weight acceptance in the stance phase, which is important for the restoration of walking ability.

  1. Real-time markerless tracking for augmented reality: the virtual visual servoing framework.

    Science.gov (United States)

    Comport, Andrew I; Marchand, Eric; Pressigout, Muriel; Chaumette, François

    2006-01-01

    Tracking is a very important research subject in a real-time augmented reality context. The main requirements for trackers are high accuracy and little latency at a reasonable cost. In order to address these issues, a real-time, robust, and efficient 3D model-based tracking algorithm is proposed for a "video see through" monocular vision system. The tracking of objects in the scene amounts to calculating the pose between the camera and the objects. Virtual objects can then be projected into the scene using the pose. Here, nonlinear pose estimation is formulated by means of a virtual visual servoing approach. In this context, the derivation of point-to-curves interaction matrices are given for different 3D geometrical primitives including straight lines, circles, cylinders, and spheres. A local moving edges tracker is used in order to provide real-time tracking of points normal to the object contours. Robustness is obtained by integrating an M-estimator into the visual control law via an iteratively reweighted least squares implementation. This approach is then extended to address the 3D model-free augmented reality problem. The method presented in this paper has been validated on several complex image sequences including outdoor environments. Results show the method to be robust to occlusion, changes in illumination, and mistracking.

  2. Servo-Elastic Dynamics of a Hydraulic Actuator Pitching a Blade with Large Deflections

    International Nuclear Information System (INIS)

    Hansen, M H; Kallesoee, B S

    2007-01-01

    This paper deals with the servo-elastic dynamics of a hydraulic pitch actuator acting on a largely bend wind turbine blade. The compressibility of the oil and flexibility of the hoses introduce a dynamic mode in the pitch bearing degree of freedom. This mode may obtain negative damping if the proportional gain on the actuator position error is defined too large relative to the viscous forces in the hydraulic system and the total rotational inertia of the pitch bearing degree of freedom. A simple expression for the stability limit of this proportional gain is derived for tuning the gain based on the Ziegler-Nichols method. Computed transfer functions from reference to actual pitch angles indicate that the actuator can be approximated as a low-pass filter with some appropriate limitations on pitching speed and acceleration. The structural blade model includes the geometrical coupling of edgewise bending and torsion for large flapwise deflections. This coupling is shown to introduce edgewise bending response for pitch reference oscillations around the natural frequency of the edgewise bending mode, in which frequency range the transfer function from reference to actual pitch angle cannot be modeled as a simple low-pass filter. The pitch bearing is assumed to be frictionless as a first approximation

  3. A versatile hydraulically operated respiratory servo system for ventilation and lung function testing.

    Science.gov (United States)

    Meyer, M; Slama, H

    1983-09-01

    A description is given of the design and performance of a microcomputer-controlled respiratory servo system that incorporates the characteristics of a mechanical ventilator and also allows the performance of a multitude of test procedures required for assessment of pulmonary function in paralyzed animals. The device consists of a hydraulically operated cylinder-piston assembly and solenoid valves that direct inspiratory and expiratory gas flow and also enable switching to different test gas sources. The system operates as a volume-flow-preset ventilator but may be switched to other operational cycling modes. Gas flow rates may be constant or variable. The system operates as an assister-controller and, combined with a gas analyzer, can function as a "demand" ventilator allowing for set-point control of end-tidal PCO2 and PO2. Complex breathing maneuvers for a variety of single- and multiple-breath lung function tests are automatically performed. Because of the flexibility in selection and timing of respiratory parameters, the system is particularly suitable for respiratory gas studies.

  4. Practical Stabilization of Uncertain Nonholonomic Mobile Robots Based on Visual Servoing Model with Uncalibrated Camera Parameters

    Directory of Open Access Journals (Sweden)

    Hua Chen

    2013-01-01

    Full Text Available The practical stabilization problem is addressed for a class of uncertain nonholonomic mobile robots with uncalibrated visual parameters. Based on the visual servoing kinematic model, a new switching controller is presented in the presence of parametric uncertainties associated with the camera system. In comparison with existing methods, the new design method is directly used to control the original system without any state or input transformation, which is effective to avoid singularity. Under the proposed control law, it is rigorously proved that all the states of closed-loop system can be stabilized to a prescribed arbitrarily small neighborhood of the zero equilibrium point. Furthermore, this switching control technique can be applied to solve the practical stabilization problem of a kind of mobile robots with uncertain parameters (and angle measurement disturbance which appeared in some literatures such as Morin et al. (1998, Hespanha et al. (1999, Jiang (2000, and Hong et al. (2005. Finally, the simulation results show the effectiveness of the proposed controller design approach.

  5. Fabrication and correction of freeform surface based on Zernike polynomials by slow tool servo

    Science.gov (United States)

    Cheng, Yuan-Chieh; Hsu, Ming-Ying; Peng, Wei-Jei; Hsu, Wei-Yao

    2017-10-01

    Recently, freeform surface widely using to the optical system; because it is have advance of optical image and freedom available to improve the optical performance. For freeform optical fabrication by integrating freeform optical design, precision freeform manufacture, metrology freeform optics and freeform compensate method, to modify the form deviation of surface, due to production process of freeform lens ,compared and provides more flexibilities and better performance. This paper focuses on the fabrication and correction of the free-form surface. In this study, optical freeform surface using multi-axis ultra-precision manufacturing could be upgrading the quality of freeform. It is a machine equipped with a positioning C-axis and has the CXZ machining function which is also called slow tool servo (STS) function. The freeform compensate method of Zernike polynomials results successfully verified; it is correction the form deviation of freeform surface. Finally, the freeform surface are measured experimentally by Ultrahigh Accurate 3D Profilometer (UA3P), compensate the freeform form error with Zernike polynomial fitting to improve the form accuracy of freeform.

  6. PID-Controller Tuning Optimization with Genetic Algorithms in Servo Systems

    Directory of Open Access Journals (Sweden)

    Arturo Y. Jaen-Cuellar

    2013-09-01

    Full Text Available Performance improvement is the main goal of the study of PID control and much research has been conducted for this purpose. The PID filter is implemented in almost all industrial processes because of its well-known beneficial features. In general, the whole system's performance strongly depends on the controller's efficiency and hence the tuning process plays a key role in the system's behaviour. In this work, the servo systems will be analysed, specifically the positioning control systems. Among the existent tuning methods, the Gain-Phase Margin method based on Frequency Response analysis is the most adequate for controller tuning in positioning control systems. Nevertheless, this method can be improved by integrating an optimization technique. The novelty of this work is the development of a new methodology for PID control tuning by coupling the Gain-Phase Margin method with the Genetic Algorithms in which the micro-population concept and adaptive mutation probability are applied. Simulations using a positioning system model in MATLAB and experimental tests in two CNC machines and an industrial robot are carried out in order to show the effectiveness of the proposal. The obtained results are compared with both the classical Gain-Phase Margin tuning and with a recent PID controller optimization using Genetic Algorithms based on real codification. The three methodologies are implemented using software.

  7. Novel Round Energy Director for Use with Servo-driven Ultrasonic Welder

    Science.gov (United States)

    Savitski, Alex; Klinstein, Leo; Holt, Kenneth

    Increasingly stringent process repeatability and precision of assembly requirements are common for high-volume manufacturing for electronic, automotive and especially medical device industries, in which components for disposable medication delivery devices are produced in hundreds of millions annually. Ultrasonic welding, one of the most efficient of plastic welding processes often joins these small plastic parts together, and quite possibly, the one most broadly adopted for high volume assembly. The very fundamental factor in ultrasonic welding process performance is a proper joint design, the most common of which is a design utilizing an energy director. Keeping the energy director size and shape consistent on a part-to-part basis in high volume, multi-cavity operations presents a constant challenge to molded part vendors, as dimensional variations from cavity to cavity and variations in the molding process are always present. A newly developed concept of energy director design, when the tip of the energy director is round, addresses these problems, as the round energy director is significantly easier to mold and maintain its dimensional consistency. It also eliminates a major source of process variability for assembly operations. Materializing the benefits of new type of joint design became possible with the introduction of servo-driven ultrasonic welders, which allow an unprecedented control of material flow during the welding cycle and results in significantly improved process repeatability. This article summarizes results of recent studies focused on evaluating performance of round energy director and investigating the main factors responsible for the joint quality.

  8. Optimal design of a main driving mechanism for servo punch press based on performance atlases

    Science.gov (United States)

    Zhou, Yanhua; Xie, Fugui; Liu, Xinjun

    2013-09-01

    The servomotor drive turret punch press is attracting more attentions and being developed more intensively due to the advantages of high speed, high accuracy, high flexibility, high productivity, low noise, cleaning and energy saving. To effectively improve the performance and lower the cost, it is necessary to develop new mechanisms and establish corresponding optimal design method with uniform performance indices. A new patented main driving mechanism and a new optimal design method are proposed. In the optimal design, the performance indices, i.e., the local motion/force transmission indices ITI, OTI, good transmission workspace good transmission workspace(GTW) and the global transmission indices GTIs are defined. The non-dimensional normalization method is used to get all feasible solutions in dimensional synthesis. Thereafter, the performance atlases, which can present all possible design solutions, are depicted. As a result, the feasible solution of the mechanism with good motion/force transmission performance is obtained. And the solution can be flexibly adjusted by designer according to the practical design requirements. The proposed mechanism is original, and the presented design method provides a feasible solution to the optimal design of the main driving mechanism for servo punch press.

  9. Multi-objective optimum design of fast tool servo based on improved differential evolution algorithm

    International Nuclear Information System (INIS)

    Zhu, Zhiwei; Zhou, Xiaoqin; Liu, Qiang; Zhao, Shaoxin

    2011-01-01

    The flexure-based mechanism is a promising realization of fast tool servo (FTS), and the optimum determination of flexure hinge parameters is one of the most important elements in the FTS design. This paper presents a multi-objective optimization approach to optimizing the dimension and position parameters of the flexure-based mechanism, which is based on the improved differential evolution algorithm embedding chaos and nonlinear simulated anneal algorithm. The results of optimum design show that the proposed algorithm has excellent performance and a well-balanced compromise is made between two conflicting objectives, the stroke and natural frequency of the FTS mechanism. The validation tests based on finite element analysis (FEA) show good agreement with the results obtained by using the proposed theoretical algorithm of this paper. Finally, a series of experimental tests are conducted to validate the design process and assess the performance of the FTS mechanism. The designed FTS reaches up to a stroke of 10.25 μm with at least 2 kHz bandwidth. Both of the FEA and experimental results demonstrate that the parameters of the flexure-based mechanism determined by the proposed approaches can achieve the specified performance and the proposed approach is suitable for the optimum design of FTS mechanism and of excellent performances

  10. A comparative design view for accurate control of servos using a field programmable gate array

    International Nuclear Information System (INIS)

    Tickle, A J; Harvey, P K; Smith, J S; Wu, F; Buckle, J R

    2009-01-01

    An embedded system is a special-purpose computer system designed to perform one or a few dedicated functions. Altera DSP Builder presents designers and users with an alternate approach when creating their systems by employing a blockset similar to that already used in Simulink. The application considered in this paper is the design of a Pulse Width Modulation (PWM) system for use in stereo vision. PWM can replace a digital-to-analogue converter to control audio speakers, LED intensity, motor speed, and servo position. Rather than the conventional HDL coding approach this Simulink approach provides an easy understanding platform to the PWM design. This paper includes a comparison between two approaches regarding resource usage and flexibility etc. Included is how DSP Builder manipulates an onboard clock signal, in order to create the control pulses to the 'raw' coding of a PWM generator in VHDL. Both methods were shown to a selection of people and their views on which version they would subsequently use in their relative fields is discussed.

  11. Fracture tolerance analysis of the solid rocket booster servo-actuator for the space shuttle

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.H.; Ghadiali, N.D.; Zahoor, A.; Wilson, M.R.

    1982-01-01

    The results of an evaluation of the fracture tolerance of three components of the thrust vector control servo-actuator for the solid rocket booster of the space shuttle are described. These components were considered as being potentially fracture critical and therefore having the potential to fall short of a desired service life of 80 missions (that is, a service life factor of 4.0 on a basic service life of 20 missions). Detailed stress analysis of the rod end, cylinder, and feedback link components was accomplished by three-dimensional finite-element stress analysis methods. A dynamic structural model of the feedback system was used to determine the dynamic inertia loads and reactions to apply to the finite-element model of the feedback link. Twenty mission stress spectra consisting of lift-off, boost, re-entry, and water impact mission segments were developed for each component based on dynamic loadings. Most components were determined to have the potential of reaching a service life of 80 missions or service life factor of 4.0. 22 refs.

  12. Indirect adaptive fuzzy wavelet neural network with self- recurrent consequent part for AC servo system.

    Science.gov (United States)

    Hou, Runmin; Wang, Li; Gao, Qiang; Hou, Yuanglong; Wang, Chao

    2017-09-01

    This paper proposes a novel indirect adaptive fuzzy wavelet neural network (IAFWNN) to control the nonlinearity, wide variations in loads, time-variation and uncertain disturbance of the ac servo system. In the proposed approach, the self-recurrent wavelet neural network (SRWNN) is employed to construct an adaptive self-recurrent consequent part for each fuzzy rule of TSK fuzzy model. For the IAFWNN controller, the online learning algorithm is based on back propagation (BP) algorithm. Moreover, an improved particle swarm optimization (IPSO) is used to adapt the learning rate. The aid of an adaptive SRWNN identifier offers the real-time gradient information to the adaptive fuzzy wavelet neural controller to overcome the impact of parameter variations, load disturbances and other uncertainties effectively, and has a good dynamic. The asymptotical stability of the system is guaranteed by using the Lyapunov method. The result of the simulation and the prototype test prove that the proposed are effective and suitable. Copyright © 2017. Published by Elsevier Ltd.

  13. An energy-saving nonlinear position control strategy for electro-hydraulic servo systems.

    Science.gov (United States)

    Baghestan, Keivan; Rezaei, Seyed Mehdi; Talebi, Heidar Ali; Zareinejad, Mohammad

    2015-11-01

    The electro-hydraulic servo system (EHSS) demonstrates numerous advantages in size and performance compared to other actuation methods. Oftentimes, its utilization in industrial and machinery settings is limited by its inferior efficiency. In this paper, a nonlinear backstepping control algorithm with an energy-saving approach is proposed for position control in the EHSS. To achieve improved efficiency, two control valves including a proportional directional valve (PDV) and a proportional relief valve (PRV) are used to achieve the control objectives. To design the control algorithm, the state space model equations of the system are transformed to their normal form and the control law through the PDV is designed using a backstepping approach for position tracking. Then, another nonlinear set of laws is derived to achieve energy-saving through the PRV input. This control design method, based on the normal form representation, imposes internal dynamics on the closed-loop system. The stability of the internal dynamics is analyzed in special cases of operation. Experimental results verify that both tracking and energy-saving objectives are satisfied for the closed-loop system. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Servo-controlled hind-limb electrical stimulation for short-term arterial pressure control.

    Science.gov (United States)

    Kawada, Toru; Shimizu, Shuji; Yamamoto, Hiromi; Shishido, Toshiaki; Kamiya, Atsunori; Miyamoto, Tadayoshi; Sunagawa, Kenji; Sugimachi, Masaru

    2009-05-01

    Autonomic neural intervention is a promising tool for modulating the circulatory system thereby treating some cardiovascular diseases. In 8 pentobarbital-anesthetized cats, it was examined whether the arterial pressure (AP) could be controlled by acupuncture-like hind-limb electrical stimulation (HES). With a 0.5-ms pulse width, HES monotonically reduced AP as the stimulus current increased from 1 to 5 mA, suggesting that the stimulus current could be a primary control variable. In contrast, the depressor effect of HES showed a nadir approximately 10 Hz in the frequency range between 1 and 100 Hz. Dynamic characteristics of the AP response to HES approximated a second-order low-pass filter with dead time (gain: -10.2 +/- 1.6 mmHg/mA, natural frequency: 0.040 +/- 0.004 Hz, damping ratio 1.80 +/- 0.24, dead time: 1.38 +/- 0.13 s, mean +/- SE). Based on these dynamic characteristics, a servo-controlled HES system was developed. When a target AP value was set at 20 mmHg below the baseline AP, the time required for the AP response to reach 90% of the target level was 38 +/- 10 s. The steady-state error between the measured and target AP values was 1.3 +/- 0.1 mmHg. Autonomic neural intervention by acupuncture-like HES might provide an additional modality to quantitatively control the circulatory system.

  15. Adaptive Hybrid Visual Servo Regulation of Mobile Robots Based on Fast Homography Decomposition

    Directory of Open Access Journals (Sweden)

    Chunfu Wu

    2015-01-01

    Full Text Available For the monocular camera-based mobile robot system, an adaptive hybrid visual servo regulation algorithm which is based on a fast homography decomposition method is proposed to drive the mobile robot to its desired position and orientation, even when object’s imaging depth and camera’s position extrinsic parameters are unknown. Firstly, the homography’s particular properties caused by mobile robot’s 2-DOF motion are taken into account to induce a fast homography decomposition method. Secondly, the homography matrix and the extracted orientation error, incorporated with the desired view’s single feature point, are utilized to form an error vector and its open-loop error function. Finally, Lyapunov-based techniques are exploited to construct an adaptive regulation control law, followed by the experimental verification. The experimental results show that the proposed fast homography decomposition method is not only simple and efficient, but also highly precise. Meanwhile, the designed control law can well enable mobile robot position and orientation regulation despite the lack of depth information and camera’s position extrinsic parameters.

  16. Evaluation of the Argonne National Laboratory servo-controlled calorimeter system

    International Nuclear Information System (INIS)

    Foster, L.A.

    1997-01-01

    The control system of a replacement mode, twin-bridge, water-bath calorimeter originally built by Mound EG ampersand G Applied Technologies was modified by Argonne National Laboratory. The calorimeter was upgraded with a PC-based computer control and data acquisition system. The system was redesigned to operate in a servo-control mode, and a preheater was constructed to allow pre-equilibration of samples. The instrument was sent to the Plutonium Facility at Los Alamos National Laboratory for testing and evaluation of its performance in the field using heat source standards and plutonium process materials. The important parameters for calorimeter operation necessary to satisfy the nuclear materials control and accountability requirements of the Plutonium Facility were evaluated over a period of several months. These parameters include calorimeter stability, measurement precision and accuracy, and average measurement time. The observed measurement precision and accuracy were found to be acceptable for most accountability measurements, although they were slightly larger than the values for calorimeters in routine use at the Plutonium Facility. Average measurement times were significantly shorter than measurement times for identical items in the Plutonium Facility calorimeters. Unexplained shifts in the baseline measurements were observed on numerous occasions. These shifts could lead to substantial measurement errors if they are not very carefully monitored by the operating facility. Detailed results of the experimental evaluation are presented in this report

  17. Towards an Aero-Propulso-Servo-Elasticity Analysis of a Commercial Supersonic Transport

    Science.gov (United States)

    Connolly, Joseph W.; Kopasakis, George; Chwalowski, Pawel; Sanetrik, Mark D.; Carlson, Jan-Renee; Silva, Walt A.; McNamara, Jack

    2016-01-01

    This paper covers the development of an aero-propulso-servo-elastic (APSE) model using computational fluid dynamics (CFD) and linear structural deformations. The APSE model provides the integration of the following two previously developed nonlinear dynamic simulations: a variable cycle turbofan engine and an elastic supersonic commercial transport vehicle. The primary focus of this study is to provide a means to include relevant dynamics of a turbomachinery propulsion system into the aeroelastic studies conducted during a vehicle design, which have historically neglected propulsion effects. A high fidelity CFD tool is used here for the integration platform. The elastic vehicle neglecting the propulsion system serves as a comparison of traditional approaches to the APSE results. An overview of the methodology is presented for integrating the propulsion system and elastic vehicle. Static aeroelastic analysis comparisons between the traditional and developed APSE models for a wing tip detection indicate that the propulsion system impact on the vehicle elastic response could increase the detection by approximately ten percent.

  18. All-Coefficient Adaptive Control of Dual-Motor Driving Servo System

    Directory of Open Access Journals (Sweden)

    Zhao Haibo

    2017-01-01

    Full Text Available Backlash nonlinearity and friction nonlinearity exist in dual-motor driving servo system, which reducing system response speed, steady accuracy and anti-interference ability. In order to diminish the adverse effects of backlash and friction nonlinearity to system, we proposed a new all-coefficient adaptive control method. Firstly, we introduced the dynamic model of backlash and friction nonlinearity respectively. Then on this basis, we established the characteristic model when backlash and friction nonlinearity coexist. We used recursive least square method for parameter estimation. Finally we designed the all-coefficient adaptive controller. On the basis of simplex all-coefficient adaptive controller, we designed a feedforward all-coefficient adaptive controller. The simulations of feedforward all-coefficient adaptive control and simplex all-coefficient adaptive control were compared. The results show that the former has quicker response speed, higher steady accuracy, stronger anti-interference performance and better robustness, which validating the efficacy of the proposed control strategy.

  19. Translating The Infinities by John Banville

    Directory of Open Access Journals (Sweden)

    Irene Abigail Piccinini

    2015-12-01

    Full Text Available Abstract - John Banville’s talent as a prose stylist is widely recognized. The polished elegance of his phrases constitutes a continuing and fascinating challenge for his translator, due to the intricacies of the source text, its manifold registers and lexical choices. In his novel The Infinities, in Italian Teoria degli Infiniti, John Banville takes cue from Kleist’s Amphytrion to devise a novel where classicality interweaves with science and science fiction through the invention of a world where the ancient gods intermingle with the humans while waiting for the death of Adam Godley, a famous mathematician who explained how an infinity of worlds exist and interact with each other. To translate this book I had not only to work extensively on lexis and style, but also to do considerable research to render the many literary and non literary references. Some examples of these struggles with the source text during the translation process are given in the present paper. Riassunto - John Banville, autore irlandese noto per la sua prosa raffinata, scrive in una lingua che rappresenta una sfida continua e affascinante per chi lo traduce. La sua complessità stilistica, che sfrutta molteplici registri linguistici e si avvale di scelte lessicali cui spesso è arduo trovare un traducente italiano soddisfacente, costringe il traduttore a fare ricorso a tutte le sottigliezze del proprio mestiere per restituire quanto più possibile l’eleganza dell’originale nella propria lingua. Nel romanzo The Infinities, tradotto in italiano come Teoria degli infiniti (Guanda, Parma 2011, Banville prende spunto dall’Anfitrione di Kleist per costruire un romanzo che guarda alla classicità sconfinando in un misto di scienza e fantascienza con la concezione di un’infinità di mondi paralleli teorizzata dal matematico Adam Godley, il protagonista morente al cui capezzale si radunano uomini e antichi dei in attesa che il cerchio della vita e della morte si compia

  20. John Hejduk's Pursuit of an Architectural Ethos

    DEFF Research Database (Denmark)

    Søberg, Martin

    2012-01-01

    Reflected, artistic practices and design-based research are drastically expanding fields within architectural academia. However, the interest in uniting theory and practice is not entirely new. Just a few decades ago, before a ‘death of theory’ was proclaimed, questions of architectural epistemol......Reflected, artistic practices and design-based research are drastically expanding fields within architectural academia. However, the interest in uniting theory and practice is not entirely new. Just a few decades ago, before a ‘death of theory’ was proclaimed, questions of architectural...... epistemology, of the language(s) of architecture, were indeed of profound interest to the discipline. This essay returns to and examines the investigatory practices of John Hejduk in an attempt to identify a poetic method asserting difference through repetition and primarily grounded in the medium...

  1. John Lumley's Contributions to Turbulence Modeling

    Science.gov (United States)

    Pope, Stephen

    2015-11-01

    We recall the contributions that John Lumley made to turbulence modeling in the 1970s and 1980s. In these early days, computer power was feeble by today's standards, and eddy-viscosity models were prevalent in CFD. Lumley recognized, however, that second-moment closures represent the simplest level at which the physics of turbulent flows can reasonably be represented. This is especially true when the velocity field is coupled to scalar fields through buoyancy, as in the atmosphere and oceans. While Lumley was not the first to propose second-moment closures, he can be credited with establishing the rational approach to constructing such closures. This includes the application of various invariance principles and tensor representation theorems, imposing the constraints imposed by realizability, and of course appealing to experimental data in simple, canonical flows. These techniques are now well-accepted and have found application far beyond second-moment closures.

  2. John Stuart Mill's Philosophy of Persuasion

    Directory of Open Access Journals (Sweden)

    Helen Ruth McCabe

    2014-02-01

    Full Text Available In his youth, John Stuart Mill followed his father’s philosophy of persuasion but, in 1830, Mill adopted a new philosophy of persuasion, trying to lead people incrementally towards the truth from their original stand-points rather than engage them antagonistically. Understanding this change helps us understand apparent contradictions in Mill’s cannon, as he disguises some of his more radical ideas in order to bring his audience to re-assess and authentically change their opinions. It also suggests a way of re-assessing the relationship between Mill’s public and private works, to which we should look if we are attempting to understand his thought.

  3. El constitucionalismo según John Rawls

    Directory of Open Access Journals (Sweden)

    Roberto Gargarella

    2005-01-01

    Full Text Available El término “democracia” se encuentra completamente ausente del famoso libro de John Rawls, Teoría de la justicia. En Liberalismo político, en cambio, Rawls discute varios de los muchos temas sobre los que el concepto de democracia nos invita a reflexionar. En este escrito concentro mi atención en una de esas discusiones: la tensión entre constitucionalismo y democracia. Más específicamente, procuro examinar de qué modo Rawls trata de afirmar el doble compromiso que toda constitución quiere honrar, esto es, el compromiso con el ideal de la autonomía individual, y el compromiso con el ideal del auto-gobierno colectivo.

  4. What John Browne actually said at Stanford

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    In May 1997, the Chief Executive of BP, John Browne, delivered a speech on global climate change at Stanford University, California. A shortened version of the speech is presented. BP have accepted the possibility of a link between greenhouse gas emissions and climate change and are basing their policies on that acceptance. The company is committed to a step-by-step process, involving both action to develop solutions and continuing research to improve knowledge, that will balance the requirements of economic development and environmental protection. Five specific steps are outlined. These are: the monitoring and controlling of carbon dioxide emissions in all aspects of the company's operations increasing the level of support given to continuing scientific work on climate change; technology transfer and joint implementation with other parties to limit and reduce net emission levels; the development of alternative energy sources, in particular, solar power; contributing to the public policy debate in search of wider global answers to the problem. (Author)

  5. John Adams and CERN: Personal Recollections

    CERN Document Server

    Brianti, Giorgio

    2013-01-01

    By any standards, John Adams had a most remarkable career. He was involved in three important, emerging technologies, radar, particle accelerators and controlled fusion, and had an outstanding impact on the last two. Without a university education, he attained hierarchical positions of the highest level in prestigious national and international organizations. This article covers the CERN part of his career, by offering some personal insights into the different facets of his contributions to major accelerator projects, from the first strong-focusing synchrotron, the PS, to the SPS and its conversion to a proton–antiproton collider. In particular, it outlines his abilities as a leader of an international collaboration, which has served as an example for international initiatives in other disciplines.

  6. John B. Little Center Annual Symposium

    International Nuclear Information System (INIS)

    Demple, Bruce F.

    2007-01-01

    The Annual Symposium of the John B. Little Center for Radiation Sciences and Environmental Health at the Harvard School of Public Health seeks to educate radiobiologists and biomedical scientists in related areas on the leading research related to the effects of ionizing radiation and related environmental agents in biological systems. This effort seeks to further the training of individuals in this field, and to foment productive interactions and collaborations among scientists at Harvard and with other institutions. The Symposium attracts world-class scientists as speakers, and a broad cross-section of attendees from academic, government, and industrial research centers, as well as editorial staff from leading scientific publications. In order to maintain this quality, funding to support the travel and local expenses of invited speakers is sought, along with funds to allow use of appropriate conference facilities.

  7. General Relativity and John Archibald Wheeler

    CERN Document Server

    Ciufolini, Ignazio

    2010-01-01

    Observational and experimental data pertaining to gravity and cosmology are changing our view of the Universe. General relativity is a fundamental key for the understanding of these observations and its theory is undergoing a continuing enhancement of its intersection with observational and experimental data. These data include direct observations and experiments carried out in our solar system, among which there are direct gravitational wave astronomy, frame dragging and tests of gravitational theories from solar system and spacecraft observations. This book explores John Archibald Wheeler's seminal and enduring contributions in relativistic astrophysics and includes: the General Theory of Relativity and Wheeler's influence; recent developments in the confrontation of relativity with experiments; the theory describing gravitational radiation, and its detection in Earth-based and space-based interferometer detectors as well as in Earth-based bar detectors; the mathematical description of the initial value pro...

  8. John B. Little Center Annual Symposium

    Energy Technology Data Exchange (ETDEWEB)

    Demple, Bruce F.

    2007-11-02

    The Annual Symposium of the John B. Little Center for Radiation Sciences and Environmental Health at the Harvard School of Public Health seeks to educate radiobiologists and biomedical scientists in related areas on the leading research related to the effects of ionizing radiation and related environmental agents in biological systems. This effort seeks to further the training of individuals in this field, and to foment productive interactions and collaborations among scientists at Harvard and with other institutions. The Symposium attracts world-class scientists as speakers, and a broad cross-section of attendees from academic, government, and industrial research centers, as well as editorial staff from leading scientific publications. In order to maintain this quality, funding to support the travel and local expenses of invited speakers is sought, along with funds to allow use of appropriate conference facilities.

  9. John Dewey and early Chicago functionalism.

    Science.gov (United States)

    Backe, A

    2001-11-01

    John Dewey and James Angell are regarded respectively as the founder and systematizer of the Chicago school of functional psychology. The early Chicago school traditionally has been portrayed as a unified theoretical approach based primarily on William James's naturalist theory of mental processes. It is argued in this article that although the psychology systematized by Angell bore a close affinity to James's naturalism, Dewey's own psychology was based primarily on the neo-Hegelian philosophy of Thomas Hill Green. Through a review of a number of Dewey's major writings, Green's neo-Hegelian philosophy is shown to have influenced Dewey's views on psychological concepts such as reaction, emotion, and perception during the formative period of the Chicago school. The interpretation of Dewey's psychology developed in this article leads to the conclusion that early Chicago functionalism should not be regarded as a unified theoretical approach.

  10. John Locke and the right to resistance

    Directory of Open Access Journals (Sweden)

    Jovanov Ilija D.

    2015-01-01

    Full Text Available John Locke was a great thinker and many works have been devoted to clear up his theories. One of the most significant, stated in his principal work, Two Treatises of Government, is the theory of the right to resistance. It was a bit revolutionary then, and to a large extent it is today. Domination of legal positivism is negation of that, by Locke, natural right. However, the fact is that in recent times the resistance to the established power occurs in a number of countries and in different forms, so that the idea of the right to resistance becomes live question again. In this regard it is interesting to consider Locke's viewpoint on this important issue and to determine whether his theory on the resistance is applicable in modern societies.

  11. John Ruskin and the Savage Gothic

    Directory of Open Access Journals (Sweden)

    Frances S. Connelly

    2015-06-01

    Full Text Available John Ruskin’s provocative theories concerning Gothic art and architecture bear serious consideration in light of the formative debates concerning “primitive” art and its relation to modern European society. Like many primitivists, Ruskin’s advocacy for the medieval was motivated by a reformist zeal concerning the state of modern industrial Europe. He differs markedly in his ideas concerning the value and uses of the "savage” Gothic for modern audiences. Ruskin rejected the random borrowing of stylistic elements, stressing instead the artisanal process and the communal role of Gothic monuments. It is also significant that Ruskin problematises the relationship between “primitive” and modern by repeatedly acknowledging his position as a modern viewer and emphasising the process through which he makes (artisan-like his interpretive history of the Gothic. Rejecting the mastering gaze, Ruskin constantly reminds readers that their view of this pre-modern work is fragmentary and disjunctive.

  12. Views of Astronaut (Col.) Joe Engle and son Jon with L-5 Piper Cub

    Science.gov (United States)

    1981-01-01

    Views of Astronaut (Col.) Joe Engle and son Jon with L-5 Piper Cub at Clover Airport. Photos include Engle turning propeller while his son sits in the cockpit (34323); both Engle and son examine propeller (34324); Engle works on engine while his son sits in cockpit (34325).

  13. Male-mediated infertility in sons of building painters and gardeners

    DEFF Research Database (Denmark)

    Ramlau-Hansen, C H; Stoltenberg, C D G; Hougaard, K S

    2012-01-01

    To investigate whether sons of gardeners and building painters have increased risk of infertility in comparison with sons of bricklayers, carpenters and electricians.......To investigate whether sons of gardeners and building painters have increased risk of infertility in comparison with sons of bricklayers, carpenters and electricians....

  14. ¿Son los MOOC una alternativa de aprendizaje?

    Directory of Open Access Journals (Sweden)

    Antonio Ramón Bartolomé Pina

    2015-01-01

    Full Text Available Este trabajo reflexiona sobre los MOOC como entornos de aprendizaje. El número de cursos masivos abiertos y en línea (MOOC ha crecido exponencialmente en pocos años desde que fueron introducidos. Los MOOC son considerados una nueva forma de entornos virtuales de aprendizaje potenciados por la tecnología. Se consideran dos tipos de MOOC: unos los organizados por Siemens y Downes (cMOOC y otros los desarrollados en lugares como Stanford, con muchos estudiantes y loables objetivos (xMOOC; estos tienen también sus debilidades. Aunque han sido recibidos con altas expectativas, también han encontrado una fuerte oposición que está aumentando con el tiempo, lo que nos permite estudiar este fenómeno en profundidad. Aunque todavía hay pocas investigaciones empíricas sobre los efectos de los MOOC en el aprendizaje, este estudio trata de arrojar luz sobre el tema desde un punto de vista teórico. En primer lugar exploraremos las expectativas positivas y negativas generadas. Los MOOC pueden constituir una buena propuesta a gran escala, lo que solo es posible para unas pocas grandes instituciones. No hay estudio de mercado, ni modelo de negocio, ni investigaciones empíricas que permitan confirmar los anuncios de sus efectos positivos. Revisaremos las teorías del aprendizaje recientes y clásicas respecto a su capacidad para explicar el proceso de aprendizaje y compararemos los cursos en línea tradicionales, los xMOOC y los cMOOC en relación a su potencial para apoyar el aprendizaje y su auto-regulación.

  15. Paradise Lost Dressed in the Costume of History: John Martin’s Rendition of Paradise Lost

    Directory of Open Access Journals (Sweden)

    Laleh Atashi

    2011-01-01

    Full Text Available The story of the loss of paradise has been read and interpreted in different ages. Commentary on Milton's Paradise Lost is not limited to verbal texts; painters and illustrators have contributed greatly to the poem by presenting their own time-bound readings and interpretations of the poem through their illustrations that are far beyond mere decorations. John Martin, in the aftermath of the Industrial Revolution, deletes the Father and the Son from his illustrations. Only angels such as Raphael are the representations of deity and are as powerless and tiny as Adam and Eve. Adam and Eve, after the Fall seem as small, powerless and as subjugated to the natural surrounding as they were before the Fall. Satan is the only powerful figure in his elegant palace. Through a new historical outlook, the researchers aim at exposing the workings of ideology and dominant discourses that informed John Martin's pictorial reading of Milton's poem in the early 19th century

  16. Evaluation and compensation of steady gas flow force on the high-pressure electro-pneumatic servo valve direct-driven by voice coil motor

    International Nuclear Information System (INIS)

    Li, Baoren; Gao, Longlong; Yang, Gang

    2013-01-01

    Highlights: ► A novel energy saving high-pressure electro-pneumatic servo valve is presented. ► An evaluated method for steady gas flow forces on pneumatic valves is proposed. ► Gas jet angles at the orifices for the valve are larger than 69° commonly used. ► The steady gas flow force is strongly nonlinear with valve opening. ► The steady gas flow force is compensated and the aim at energy saving is realized. - Abstract: A novel voice coil motor (VCM) direct drive single stage high-pressure pneumatic servo valve is designed, and then the steady gas flow force acting on the spool of the servo valve is investigated by numerical simulation and experimental methods in this paper. At present, many studies about flow force are concentrated mainly on hydraulic valves, but rarely on pneumatic valves. However, the velocity of gas is up to sonic when high-pressure gas flows through the servo valve orifice. And therefore, the steady gas flow force, generated by high pressure and high speed gas flow, cannot be neglected and is an important disturbance for the VCM direct-drive single stage high-pressure pneumatic servo valve. Consequently, the numerical simulation with computational fluid dynamics (CFD) is adopted to analyze the flow filed, jet angles, and steady gas flow forces for the servo valve with different valve openings and inlet pressures. The experimental study is performed to evaluate and confirm the numerical analysis. Then the compensated approach is proposed to reduce the steady gas flow force for the servo valve, changing the angle of non-metering port designed in the valve sleeve to the spool axis. The results demonstrate that the presented numerical analysis method is validated, the gas jet angle for the servo valve orifice is more than 69° and varies with different spool openings, and the steady gas flow force is nonlinear with valve opening and linear with inlet pressure when the outlet boundary is atmospheric pressure. Moreover, the steady gas

  17. Breathing Silence. An interview with John Palmer

    Directory of Open Access Journals (Sweden)

    Cristina Scuderi

    2011-07-01

    Full Text Available The interview focuses on some aspects of the composer’s work with electronics. Palmer, described by the critics as «undoubtedly the most visionary composer of his generation» speaks about the composers and musical works that have had a major impact on him. He also mentions the friendship with John Cage, his numerous travels – with particular emphasis on Japan – and the influence of Eastern culture on his musical mind. The composer discusses the notion of causality explored in Renge-Kyo, the meditative nature of Transient and Inwards, and spirituality as the central theme of both acousmatic works In the Temple and I Am. The electronic medium is also por- trayed as a mirror of an intense and vivid preoccupation for intimacy and perpetual search for timbral qualities that by now characterize most of his music. Another important aspect of Palmer’s work mentioned in the interview is the collaboration with some established performers and its importance for the realization of a musical work.

  18. John Bardeen and the theory of superconductivity

    International Nuclear Information System (INIS)

    Schrieffer, J.R.

    1992-01-01

    Bardeen's knowledge of the experimental data had bounded the theory of superconductivity quite tightly before B, C and S developed their theory. When one speaks with John Bardeen's friends about him, one frequently hears words such as brilliant, quiet, persistent, generous, visionary, athletic, kind, thoughtful and remarkable. It is the author's good fortune to have the chance to recount some incidents from his life that are connected with the theory of superconductivity. This article draws on the author's personal memories; his many other friends and colleagues will set down their own recollections elsewhere. The evolution of the microscopic theory of superconductivity closely parallels the scientific life of Joh Bardeen. Starting with his PhD dissertation, done under the guidance of Eugene Wigner, he spent much of his life developing an understanding of electron interaction effects and transport properties of metals, semiconductors and superconductors. His fascination with the remarkable phenomenon of superconductivity goes back to his graduate student days at Princeton. Although interrupted during the war years and in the late 1940's at Bell Labs, he returned to this perplexing topic when he moved to the University of Illinois in 1951. 20 refs., 7 figs

  19. The life and works of John Napier

    CERN Document Server

    Rice, Brian; Corrigan, Alexander

    2017-01-01

    For the first time, all five of John Napier’s works have been brought together in English in a single volume, making them more accessible than ever before. His four mathematical works were originally published in Latin: two in his lifetime (1550–1617), one shortly after he died, and one over 200 years later. The authors have prepared three introductory chapters, one covering Napier himself, one his mathematical works, and one his religious work. The former has been prepared by one of Napier’s descendants and contains many new findings about Napier’s life to provide the most complete biography of this enigmatic character, whose reputation has previously been overshadowed by rumour and speculation. The latter has been written by an academic who was awarded a PhD for his thesis on Napier at the University of Edinburgh, and it provides the most lucid and coherent coverage available of this abstruse and little understood work. The chapter on Napier’s mathematical texts has been authored by an experienced...

  20. John Dique: dialysis pioneer and political advocate.

    Science.gov (United States)

    George, Charles R P

    2016-02-01

    John Dique (1915-1995) epitomized the internationalism of medicine, the intellectual and manual dexterity of many pioneers of dialysis, and the social concern evinced by many nephrologists. Born in Burma of French, German, British and Indian ancestry; educated in India; an Anglo-Indian who described himself as British without ever having visited Britain; he moved to Australia in 1948 to escape the murderous inter-ethnic conflict that befell multicultural India as it and Pakistan became independent. Settling in Brisbane, he pioneered several novel medical techniques. After inventing some simple equipment to facilitate intravenous therapy, he established a neonatal exchange blood transfusion programme. Then, between 1954 and 1963, he personally constructed and operated two haemodialysis machines with which to treat patients suffering from acute renal failure, the first such treatment performed in Australasia. His patients survival results were, for the era, remarkable. He subsequently helped found the Royal Australasian College of Pathologists and went on to establish a successful private pathology practice. The latter years of his life, however, saw him become a social and political advocate. He fiercely opposed the emerging ideologies of multiculturalism and social liberalism that, he predicted, would seriously damage the national fabric of Western society. Public vilification ensued, his medical achievements disregarded. It does seem likely, however, that in none of the areas that he touched - whether medical, social, or political - has the last word yet been said.