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ABSTRACT: In this paper, two controllers are developed for nonlinear haptic and teleoperator systems for coordination of the master and slave systems. The first controller is proven to yield a semi-global asymptotic result in the presence of parametric uncertainty in the master and the slave dynamic models provided the user and the environmental input forces are measurable. The second controller yields a global asymptotic result despite unmeasurable user and environmental input forces provided the dynamic models of the master and slave are known. These controllers rely on a transformation and a flexible target system to allow the master system's impedance to be easily adjusted so that it matches a desired target system. This work also offers a structure to encode a velocity field assist mechanism to provide the user help in controlling the slave system in completing a pre-defined contour following task. For each controller, Lyapunov-based techniques are used to prove that both controllers provide passive coordination of the haptic/teleoperator system when the velocity field assist mechanism is disabled. When the velocity field assist mechanism is enabled, the analysis proves the coordination of the haptic/teleoperator system
Decision and Control, 2006 45th IEEE Conference on; 01/2007
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ABSTRACT: Significant research has been aimed at the development and control of teleoperator systems. Two controllers are developed in this paper for a nonlinear teleoperator system that targets coordination of the master and slave manipulators and passivity of the overall system. The first controller is proven to yield a semi-global asymptotic result in the presence of parametric uncertainty in the master and slave manipulator dynamic models. The second controller yields a global asymptotic result despite unmeasurable user and environmental input forces. To develop each controller a transformation encodes the coordination and passivity requirements within the closed loop system. The coordinated system is forced to track a dynamic system to assist in meeting all control objectives. Finally, continuous nonlinear integral feedback terms are used to accommodate for incomplete system knowledge for both of the controllers. Lyapunov-based techniques are used to prove that all control objectives are met and that all signals are bounded
Advanced Intelligent Mechatronics. Proceedings, 2005 IEEE/ASME International Conference on; 08/2005
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ABSTRACT: In this paper, we consider the problem of task-space tracking control of robot manipulators. Based on a quaternion representation of the end-effector orientation, we design a class of task-space controllers that ensure asymptotic end-effector position and orientation tracking. To facilitate the control design, we first develop model-based and adaptive full-state feedback controllers. We then present a model-based output feedback controller that eliminates link velocity measurements via a model-based observer. The application of the proposed control strategy to redundant robots is also discussed. Simulation results based on a six-link manipulator system are presented for the output feedback controller.
IEEE Transactions on Robotics and Automation 03/2004;
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ABSTRACT: A high precision, cost effective, experimental hardware-in-the-loop steer-by-wire test environment is presented and discussed to support engineering and psychology studies. In this project, a suite of chassis models and nonlinear control algorithms are developed and validated, as well as various human-machine interface design issues investigated. This paper provides an overview of the real time steering simulator which has been created to facilitate the comparison and evaluation of vehicle and steering system control strategies in a repeatable manner. The insertion of novel driver input devices, with adjustable force feedback, permits the study of the human-vehicle interface. The remote operation and/or supervision of semi-autonomous or autonomous vehicles can be studied using a human-in-the-loop system to provide insight into the relative importance to the driver of various vehicle parameters.
American Control Conference, 2003. Proceedings of the 2003; 07/2003
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ABSTRACT: In this paper, we investigate the translational and rotational motion of the end-effector of a robot under visual feedback from a fixed camera. We achieve an exponential stability result for the regulation of the end-effector to a desired location and orientation. Specifically, by utilizing visual information from one fixed camera, we capture the motion of 4 points located in a fictitious plane attached to the end-effector in Cartesian space. By assuming knowledge of the camera intrinsic parameters, we obtain the rotational motion of the end-effector through a homography decomposition while utilizing the pixel motion of one of the four points to obtain the translation information. The stability of the controller is proven through a Lyapunov-based stability analysis.
American Control Conference, 2003. Proceedings of the 2003; 07/2003
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ABSTRACT: The functionality of gasoline and diesel engine thermal management systems can be enhanced through the introduction of a smart thermostat valve and variable speed water pump. A nonlinear tracking controller is presented in this paper for advanced thermal management systems applicable to ground vehicles. Specifically, the controller is designed to ensure that the engine temperature follows a desired temperature trajectory which may be prescribed based on operating conditions. Further, the heat rejected from the system at the radiator is controlled by adjusting the radiator fan's speed. The controller ensures that the engine temperature tracking error is asymptotically forced to zero while compensating for the unmeasurable heat input from the engine's combustion process.
American Control Conference, 2003. Proceedings of the 2003; 07/2003
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ABSTRACT: In this paper, the standard indirect field-oriented controller (IFOC) commonly used in current-fed induction motor drives is modified to achieve global exponential rotor velocity/rotor flux tracking. The modifications to the IFOC scheme, which involve the injection of nonlinear terms into the current control input and the so-called desired rotor flux angle dynamics, facilitate the construction of a standard Lyapunov stability argument. The construction of a standard Lyapunov exponential stability argument allows one to easily design adaptive controllers to compensate for parametric uncertainty associated with the mechanical load. Simulation results are included to illustrate the improvement in performance over the standard IFOC scheme.
IEEE Transactions on Control Systems Technology 04/2003; · 1.77 Impact Factor
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ABSTRACT: In an effort to improve sub-molecular imaging precision, a general distributed-based modeling approach for the atomic force microscope system is proposed which allows for the design of a stabilizing controller/estimation scheme that stabilizes the micro-cantilever based system while asymptotically identifying the atomic interaction force, that is, the estimated interaction force asymptotically approaches the actual interaction force; hence the estimated interaction force can be utilized to generate high precision atomic-resolution images. Differing from current practices of simple lumped model sets of ordinary differential equations, the proposed approach attacks the more difficult distributed parameter model.
Decision and Control, 2002, Proceedings of the 41st IEEE Conference on; 01/2003
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ABSTRACT: In this paper, a continuous time-varying tracking controller is designed for a steer-by-wire system in a automotive vehicle to ensure that the vehicles position/orientation follow that of a reference generator. The tracking error is globally and exponentially forced to a neighborhood about zero that can be made arbitrarily small (i.e., globally, uniformly and ultimately boundedness). The result is facilitated by transforming the system into a flat input-state system and then fusing a filtered tracking error transformation with the dynamic oscillator design. We also illustrate that the proposed tracking controller yields a globally, uniformly and ultimately bounded result for the regulation problem.
American Control Conference, 2002. Proceedings of the 2002; 02/2002
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ABSTRACT: In this paper, we design a nonlinear controller for the kinematic model of an underactuated rigid spacecraft that ensures uniform, ultimately bounded (UUB) tracking provided the initial errors are selected sufficiently small. The result is achieved via a judicious formulation, of the spacecraft kinematics and the novel design of a Lyapunov-based controller. We also discuss how standard backstepping control techniques can be fused with the kinematic controller to solve the full-order regulation problem for an axisymmetric spacecraft.
American Control Conference, 2002. Proceedings of the 2002; 02/2002
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ABSTRACT: In this paper, we consider the problem of task-space tracking control of redundant robot manipulators. Based on a quaternion representation of the end-effector orientation, we design a class of task-space controllers that ensure asymptotic end-effector position and orientation tracking. To facilitate the control design, we first develop model-based and. adaptive full-state feedback controllers. We then present a model-based output feedback controller that eliminates link velocity measurements via a model-based observer
Control Applications, 2001. (CCA '01). Proceedings of the 2001 IEEE International Conference on; 02/2001
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ABSTRACT: In this paper, we present a nonlinear tracking controller for the
nonminimum-phase, underactuated model of a vertical take off and landing
(VTOL) aircraft. Specifically, the controller is designed to ensure that
the VTOL aircraft position/orientation tracks a reference signal
generator. The controller ensures that the position/orientation tracking
error can be exponentially forced into an arbitrarily small neighborhood
around zero (i.e., globally uniformly ultimately bounded (GUUB)
tracking)
Decision and Control, 2001. Proceedings of the 40th IEEE Conference on; 02/2001
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ABSTRACT: Robotic systems are well suited for decontamination and
decommissioning (D&D) tasks in hazardous environments. Advanced
semi-autonomous telerobotic solutions for D&D tasks go beyond simple
video-based interaction and include virtual reality (VR) interfaces and
flexible sensor integration. The capability of those systems range from
real-time control tasks to graphical user interface components utilizing
video and VR. This paper describes QRobot, a PC-based system for
telerobotic D&D operations. The system integrates hardware
interfacing, real-time joint level control, sensors, tool control,
networking and task level programming as well as video and VR based
operator interfaces. The system demonstrates that the personal computer
(PC), a cost effective and widely used computing platform, is well
suited to the integration of real-time control tasks and advanced user
interfaces
Computer-Aided Control System Design, 2000. CACSD 2000. IEEE International Symposium on; 02/2000
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ABSTRACT: We present a sensorless rotor velocity tracking controller for the
full order, nonlinear dynamic model of the permanent magnet stepper
motor actuating a mechanical subsystem. Specifically, the structure of
the electrical subsystem dynamics is exploited to reconstruct the rotor
position and velocity signals from measurements of stator current and
stator voltage. This surrogate rotor position signal is then used to
design a control strategy that achieves exponential rotor velocity
tracking. Experimental results are included to demonstrate the efficacy
of the proposed algorithm
Control Applications, 2000. Proceedings of the 2000 IEEE International Conference on; 02/2000
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ABSTRACT: This paper describes QMotor 2.0, a QNX based single-processor
software environment that allows the implementation of real-time control
programs on standard Intel processor based personal computers (PCs). The
control program, as well as the development tools and graphical user
interface, can all execute simultaneously on the PC due to the
deterministic response of the operating system. This architecture
replaces the traditional multiprocessor Host/DSP board architecture used
in control applications. Advantages of a single-processor system include
reduced cost and complexity, as well as increased flexibility and
upgradability. Since its development, QMotor 2.0 has been used
successfully in all of the control experiments, including motor and
robot control, active magnetic bearing experiments, web handling, and
vibration control in flexible structures
IEEE control systems 07/1999; · 2.49 Impact Factor
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ABSTRACT: This paper provides a solution to the composite adaptive output
feedback tracking control problem for robotic manipulators. The proposed
controller utilizes an update law that is a composite of a gradient
update law driven by the link position tracking error and a least
squares update law driven by the prediction error. In order to remove
the controller's dependence on link velocity measurements, a linear
filter and a new prediction error formulation are designed. The
controller provides semi-global asymptotic link position tracking
performance
American Control Conference, 1999. Proceedings of the 1999; 02/1999
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[show abstract]
[hide abstract]
ABSTRACT: We illustrate how the standard indirect field oriented controller
(IFOC) commonly used in current-fed induction motor drives can be
modified to achieve global exponential rotor velocity/rotor flux
tracking. The modifications to the IFOC scheme, which involve the
injection of nonlinear terms into the current control input and the
so-called desired rotor flux angle dynamics, facilitate the construction
of a standard Lyapunov stability argument. The construction of a
standard Lyapunov exponential stability argument allows one to easily
design adaptive controllers to compensate for parametric uncertainty
associated with the mechanical load
Control Applications, 1999. Proceedings of the 1999 IEEE International Conference on; 02/1999
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International Journal of Systems Science. 01/1999; 30(5):515-525.
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ABSTRACT: We describe QRobot, a low level real-time PC-based system for
controlling PUMA robot manipulators. Specifically, we illustrate how a
standard PUMA controller can be retrofitted with interface boards that
allow it to be connected to a standard PC. All computational units are
removed from the existing PUMA controller, and the PC assumes the role
of computing the control strategy. A low level control is implemented
for a PUMA 560 manipulator. The low level control software is then
connected to two high level software environment for purposes of high
level trajectory generation, kinematics, inverse kinematics, etc.
Excellent tracking results are obtained with both systems. Some
limitations of the two high level software environments were discovered
during the development of QRobot. These limitations provide the
motivation for the future development of a new object oriented robot
control system
Control Applications, 1998. Proceedings of the 1998 IEEE International Conference on; 10/1998
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ABSTRACT: This paper addresses the problem of global output feedback, link
position tracking control of robot manipulators in the presence of
parametric uncertainty and additive bounded disturbances. Specifically,
a Lyapunov-based robust controller is designed to ensure that the link
position tracking error is globally, uniformly and ultimately bounded
even if only link position measurements are available for measurement.
Experimental results are provided to illustrate the controller
performance
Control Applications, 1998. Proceedings of the 1998 IEEE International Conference on; 10/1998
