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ABSTRACT: A nonlinear observer based method is proposed to solve the forward kinematics problem of the 6-DOF parallel manipulator (Stewart platform). In this paper, the forward kinematics solution is achieved by using a nonlinear observer designed to estimate the system states including 3-axis translations and rotations. The forward kinematics problem of the Stewart platform is often solved using Newton-Raphson method which is an iterative process to approach the true solution. Another approach is to solve a high-order polynomial via the elimination-based method. Each method is difficult to practice because of the complexity of formulation and computational burden. The nonlinear observer based method avoids the complicated polynomial and iteration such that the calculation time can be greatly saved and the forward kinematics solution can work in real time.
Control Applications, 2008. CCA 2008. IEEE International Conference on; 10/2008
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ABSTRACT: In this paper, we will propose a nonlinear adaptive controller for a linear induction motor to achieve speed tracking. A nonlinear transformation is proposed to facilitate controller design. In this controller, only the primary currents are assumed to be measured. The secondary flux and speed observers are designed to relax the need offlux and speed measurement. Besides, the very unique end effect of the linear induction motor is also considered and is well taken care of in our controller design. Stability analysis based on Lyapunov theory is also performed to guarantee that the controller design here is stable. Also, the computer simulations and experiments are done to demonstrate the performance of Nomenclature.
Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
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ABSTRACT: In this paper, a differential game based guidance law for intercepting missiles is proposed. This guidance law, named the zero-sliding guidance law, is combined with the differential game theory. Players in this differential game are the missile and the target, respectively. The cost function is the component of the relative velocity which is based on the zero-sliding guidance law. An optimal strategy pair of the missile and the target can be obtained from the differential game theory based guidance law. The interception can handle both the non-maneuvering target and the maneuvering target with the perfect information. The various simulation results can guarantee the performance and stability of our designed system.
Industrial Electronics Society, 2007. IECON 2007. 33rd Annual Conference of the IEEE; 12/2007
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ABSTRACT: In this paper, we propose a nonlinear adaptive controller and an adaptive backstepping controller for linear induction motors to achieve position tracking. A nonlinear transformation is proposed to facilitate controller design. In addition, the very unique end effect of the linear induction motor is also considered and is well taken care of in our controller design. We also consider the effect of friction dynamics and employ observer-based compensation to cope with the friction force. A stability analysis based on Lyapunov theory is also performed to guarantee that the controller design here can stabilize the system. Also, the computer simulations and experiments are conducted to demonstrate the performance of our various controller design.
IEEE/ASME Transactions on Mechatronics 09/2007; · 2.87 Impact Factor
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ABSTRACT: In this paper, we propose a highly maneuverable autopilot system based on multiple Thrust Vector Control (TVC) mechanisms and Divert Control System (DCS). The strategy of the cooperation of multiple TVC mechanisms and DCS is discussed. Moreover, the decision and control part in missiles: guidance law (GL) and autopilot is presented. The GL is designed with dynamic sliding mode control (DSMC) to eliminate the chattering phenomenon caused by sliding mode control (SMC) and to minimize the distance between the missile and the target without the estimation of interception time. The autopilot controller based on quaternion representation is designed using backstepping control technique to execute the attitude command. The stability of the integrated guidance/autopilot (G/A) system is analyzed by Lyapunov stability theory. In addition, we advocate a wingless missile to reduce the nonlinear effect from the aerodynamics as much as possible. Extensive simulations including aerodynamic model are finally demonstrated to verify the validity of the proposed integrated G/A systems of missiles incorporating the highly maneuverable inputs.
American Control Conference, 2007. ACC '07; 08/2007
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ABSTRACT: In this paper, we propose a new approach "HVB senseless maneuver optimal washout filter" which is based on human vestibular system, senseless maneuver and motion platform limitation for designing washout filter such that a cost function constraining the pilot sensation error (between simulator and vehicle) is minimized. This approach can curtail over strong feelings of pilot reception and increase efficiency of platform workspace for task running. Finally, the experimental results confirm the effectiveness of our algorithm hereby proposed. Moreover, the results show that a better performance can be attained
Systems, Man and Cybernetics, 2006. SMC '06. IEEE International Conference on; 11/2006
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ABSTRACT: This paper presents a smooth sliding mode control approach for the motion control of a Stewart platform. The control scheme is proposed given that the overall system parameters are subject to uncertainties while only the positions and velocities of links are measurable. To achieve high performance tracking control of a 6 DOF Stewart platform normally requires the full knowledge of the system dynamics. In this paper, some important properties of the dynamics of the Stewart platform have been derived and exploited to develop a sliding mode controller which can drive the motion tracking error to zero asymptotically. Stability analysis based on Lyapunov theory is performed to guarantee that the controller design is stable. Finally, the experimental results confirm the effectiveness of our control design
Control Applications, 2005. CCA 2005. Proceedings of 2005 IEEE Conference on; 09/2005
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ABSTRACT: This paper presents an adaptive backstepping control approach for the motion control of a Stewart platform. The control scheme is proposed given that the overall system parameters are subject to uncertainties while only the positions and velocities of links are measurable. To achieve high performance tracking control of a 6 DOF Stewart platform normally requires the full knowledge of the system dynamics. In this paper, some important properties of the dynamics of the Stewart platform have been derived and exploited to develop an adaptive backstepping controller which can drive the motion tracking error to zero asymptotically. Stability analysis based on Lyapunov theory is performed to guarantee that the controller design is stable. Finally, the experimental results confirm the effectiveness of our control design.
Decision and Control, 2004. CDC. 43rd IEEE Conference on; 01/2005
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ABSTRACT: This paper proposed a novel way to design and analysis nonlinear controllers to deal with the tracking problem of a wheeled mobile robots (WMR) with nonholonomic constraints. One of the nonlinear controllers is adopted to control the system with position and torque tracking requirements simultaneously. Another one is chosen to follow the path considering with position, torque and actuator dynamics by backstepping control. Both of feedback systems are shown to be exponentially stable via Laypunov stability analysis. In order to guarantee the high performance operation of brushless DC motors (BLDCM) in such applications, the nonlinear model are accounted for increasing the precision actions through accuracy sketching nonlinear behaviours. The performances of controllers are verified through simulations.
Systems, Man and Cybernetics, 2004 IEEE International Conference on; 11/2004
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ABSTRACT: In this note, we have proposed a systematic approach for the hybrid system controller designs. We integrate discrete event system (DES) and continuous variable dynamic system (CVDS) theories, while taking both sizes of operation logics as well as the system performance into account, to propose a novel approach for the hybrid system controller design. In order to verify the performance of the proposed controllers, we perform a number of computer simulations of a real-world HVAC hybrid system.
Control Applications, 2004. Proceedings of the 2004 IEEE International Conference on; 10/2004
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ABSTRACT: This work presents a new multi-plane air combat simulator based on the visual servo system. The scenario is an air combat of two fighters in virtual reality. The escaping one is simulated by a Stewart platform with a force-feedback joystick, overall controlled by a human operator. The chaser is realized as a visual servo system, as if the simulated air fighter was equipped with a military light-of-sight (LOS) to lock on to the mentioned escaping air fighter. Specifically, any arbitrary-shaped object that appears on a screen reflecting the virtual space of the escaping fighter can be automatically detected and located by the visual system in real-time so that the 2-DOF camera simulating LOS can be controlled due to visual servo to keep the target object centered in the camera image. By sensing the motion of the camera platform, the autopilot of the chasing fighter tries to follow the escaping one as closely as possible with an aim of shooting it down. The overall system is experimented in a virtual reality environment to validate the underlying research work. A promising application of this setup is to evolve into an entertainment facility or a military training platform.
Control Applications, 2004. Proceedings of the 2004 IEEE International Conference on; 10/2004
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ABSTRACT: This paper presents a sliding mode control approach for the motion control of a Stewart platform. The control scheme is proposed given that the overall system parameters are subject to uncertainties while only the positions and velocities of links are measurable. To achieve high performance tracking control of a 6 DOF Stewart platform normally requires the full knowledge of the system dynamics. In this paper, some important properties of the dynamics of the Stewart platform have been derived and exploited to develop a sliding-mode controller which can drive the motion tracking error to zero asymptotically. Stability analysis based on Lyapunov theory is performed to guarantee that the controller design is stable. Finally, the experimental results confirm the effectiveness of our control design.
Control Conference, 2004. 5th Asian; 08/2004
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ABSTRACT: In this paper, we propose a nonlinear passivity based controller for a double inverted pendulum system, consisting of a two-link pendulum mounted on a pad which is moved by a linear induction motor so that the double pendulum points straight-up. The proposed controller not only can drive the double pendulum from its "natural stable hanging position" to its "unstable upright inverted position" while linear the induction motor's displacement is brought to zero but also can guarantee that the motor with very unique end-effect can achieve servo motion tracking with high performance. Also, computer simulations are provided to demonstrate the effectiveness of the hereby presented controller design.
Control Applications, 2003. CCA 2003. Proceedings of 2003 IEEE Conference on; 07/2003
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ABSTRACT: We propose a nonlinear adaptive controller and an adaptive backstepping controller for a linear induction motor to achieve speed/position tracking. A nonlinear transformation is proposed to facilitate controller design. Besides, the very unique end effect of the linear induction motor is also considered and is well taken care of in our controller design. We also consider the friction dynamics effect and employ observer-based compensation which cope with friction force. Stability analysis based on Lyapunov theory is also performed to guarantee that the controller design is stable. Also, the computer simulations and experiments are done to demonstrate the performance of our various controller designs.
Decision and Control, 2002, Proceedings of the 41st IEEE Conference on; 01/2003
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ABSTRACT: In this paper, we propose a nonlinear adaptive controller and an adaptive backstepping controller for linear induction motors (LIMs) to achieve speed/position tracking. A nonlinear transformation is proposed to facilitate controller design. Besides, the unique end effect of the LIM is also considered and is well taken care of in our controller design. Stability analysis based on Lyapunov theory is also performed to guarantee that the controller design is stable. Also, computer simulations and experiments are undertaken to demonstrate the performance of our controller designs.
American Control Conference, 2002. Proceedings of the 2002; 02/2002
