As many systems depend on electronics, concern for fault tolerance is growing rapidly. For example, a car with its steering controlled by electronics and no mechanical linkage from steering wheel to front tires (steer...
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As many systems depend on electronics, concern for fault tolerance is growing rapidly. For example, a car with its steering controlled by electronics and no mechanical linkage from steering wheel to front tires (steer...
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As many systems depend on electronics, concern for fault tolerance is growing rapidly. For example, a car with its steering controlled by electronics and no mechanical linkage from steering wheel to front tires (steer-by-wire) should be fault tolerant because a failure can come without any warning and its effect is devastating. In order to make system fault tolerant, there has been a body of research mainly from aerospace field. This paper presents the structure of predictive hybrid redundancy that can filter out most erroneous values. In addition, several numerical simulation results are given where the predictive hybrid redundancy outperforms well-known average and median voters.
In semiconductor packaging applications, e.g., wire bonding, high speed and high precision are two core requirements. Five-bar linkages are good candidates for 2-DoF (degree of freedom) semiconductor manipulation beca...
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In semiconductor packaging applications, e.g., wire bonding, high speed and high precision are two core requirements. Five-bar linkages are good candidates for 2-DoF (degree of freedom) semiconductor manipulation because of its parallel topology and therefore its potential for high speed and high precision. In order to find the best five-bar structure, the workspace volume index (WVI), the ratio of workspace volume to machine envelop size, is proposed as a measure for kinematic performance. Optimal design problems are formulated by regarding WVI as the objective function and other requirements on dexterity and singularitylessness as the constraints. Based on the design formulation, two candidate manipulators, the 5-R and PRRRP manipulators are compared with respect to WVI, kinematic accuracy, stiffness and velocity transmission, etc.
作者：
M. FeemsterD.M. DawsonA. BehalW. DixonMatthew Feemster received the B.S degree in Electrical Engineering from Clemson University
Clemson South Carolina in December 1994. Upon graduation he remained at Clemson University and received the M.S. degree in Electrical Engineering in 1997. During this time he also served as a research/teaching assistant. His research work focused on the design and implementation of various nonlinear control algorithms with emphasis on the induction motor and mechanical systems with friction present. He is currently working toward his Ph.D. degree in Electrical Engineering at Clemson University. Darren M. Dawson was born in 1962
in Macon Georgia. He received an Associate Degree in Mathematics from Macon Junior College in 1982 and a B.S. Degree in Electrical Engineering from the Georgia Institute of Technology in 1984. He then worked for Westinghouse as a control engineer from 1985 to 1987. In 1987 he returned to the Georgia Institute of Technology where he received the Ph.D. Degree in Electrical Engineering in March 1990. During this time he also served as a research/teaching assistant. In July 1990 he joined the Electrical and Computer Engineering Department and the Center for Advanced Manufacturing (CAM) at Clemson University where he currently holds the position of Professor. Under the CAM director's supervision he currently leads the Robotics and Manufacturing Automation Laboratory which is jointly operated by the Electrical and Mechanical Engineering departments. His main research interests are in the fields of nonlinear based robust adaptive and learning control with application to electro-mechanical systems including robot manipulators motor drives magnetic bearings flexible cables flexible beams and high-speed transport systems. Aman Behal was born in India in 1973. He received his Masters Degree in Electrical Engineering from Indian Institute of Technology
Bombay in 1996. He is currently working towards a Ph.D in Controls and Robotics at Clemson University. His research focuses on the control of no
In this paper, we extend the observer/control strategies previously published in [25] to an n -link, serially connected, direct drive, rigid link, revolute robot operating in the presence of nonlinear friction effects...
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In this paper, we extend the observer/control strategies previously published in [25] to an n -link, serially connected, direct drive, rigid link, revolute robot operating in the presence of nonlinear friction effects modeled by the Lu-Gre model. In addition, we also present a new adaptive control technique for compensating for the nonlinear parameterizable Stribeck effects. Specifically, an adaptive observer/controller scheme is developed which contains a feedforward approximation of the Stribeck effects. This feedforward approximation is used in a composite controller/observer strategy which forces the average square integral of the position tracking error to an arbitrarily small value. Experimental results are included to illustrate the performance of the proposed controllers.
In conventional cross-coupled controller design,the method usually ignored the inherent characteristic of time-vary- ing parameters and model uncertainties in *** this paper,a cross-coupled controller(CCC)using an H~...
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In conventional cross-coupled controller design,the method usually ignored the inherent characteristic of time-vary- ing parameters and model uncertainties in *** this paper,a cross-coupled controller(CCC)using an H~∞control scheme has been proposed to reduce the contouring error for an X-Y ***,the proposed CCC design,which is a typical Multi- Input Multi-Output(MIMO)system with linear time varying(LTV)characteristics,has been verified as being internally stable. The simulations are carried on Matlab simulink to verify the proposed method,and the results showed that the proposed method can reduce the contouring error significantly compared with the conventional one.
A new method for arbitrary 3d-object reconstruction in unknown environment is proposed in this paper. The implicit surface is reconstructed based on radial basis functions network from range scattered data. For the pr...
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In conventional cross-coupled controller design, the method usually ignored the inherent characteristic of time-varying parameters and model uncertainties in system. In this paper, a cross-coupled controller (CCC) usi...
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In conventional cross-coupled controller design, the method usually ignored the inherent characteristic of time-varying parameters and model uncertainties in system. In this paper, a cross-coupled controller (CCC) using an H infinity control scheme has been proposed to reduce the contouring error for an X-Y table. Furthermore, the proposed CCC design, which is a typical Multi-Input Multi-Output (MIMO) system-with linear time varying (LTV) characteristics, has been verified as being internally stable. The simulations are carried on Matlab simulink to verify the proposed method, and the results showed that the proposed method can reduce the contouring error significantly compared with the conventional one.
In this paper, robust force/motion control strategies are presented for mobile manipulators under both holonomic and nonholonomic constraints in the presence of uncertainties and disturbances. Robust controls are prop...
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In this paper, robust force/motion control strategies are presented for mobile manipulators under both holonomic and nonholonomic constraints in the presence of uncertainties and disturbances. Robust controls are proposed based on a simplified dynamic model, the defined reference signals and the mixed tracking errors. The proposed control strategies guarantee that the system motion converges to the desired manifold with prescribed performance. Constraint force control is developed, which does not utilize force feedback control but is based on the passivity of hybrid joint. Experiment results validate not only the states of the system asymptotically converge to the desired trajectory but also the constraint force asymptotically converges to the desired force
Active vibration damping of flexible structures requires the positioning of actuators and sensors along the structure. When the actuators become particularly small in comparison to the structure a large number of mode...
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Active vibration damping of flexible structures requires the positioning of actuators and sensors along the structure. When the actuators become particularly small in comparison to the structure a large number of modes is necessary to accurately represent the response of the structure. Neglecting these higher modes may result in a spillover phenomenon which is capable of destabilizing the closed loop system. Therefore proper correction methods to account for the dynamics of higher modes in the structural model have to be found. One such possibility is the utilization of Frequency Response Modes (FRM), a special form of the particular solution of the equations of motion of a flexible structure. In this paper the FRM is defined and used for model correction of a simply supported beam. Finally correction terms are used to quantize local actuator action.
This paper is concerned with the application of a heuristic approach in the design of a fault-tolerant control system for ship steering. It proposes an advanced reconfigurable control system (RCS) for ship course chan...
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