Design Modeling And Motion Control Of Tendon Based Parallel Manipulators PDF Download

This dissertation, "Kinematics, Dynamics and Control of High Precision Parallel Manipulators" by Wing-fung, Jacob, Cheung, 張穎鋒, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstracts of thesis entitled Kinematics, Dynamics and Control of High Precision Parallel Manipulators Submitted by Cheung Wing Fung Jacob for the degree of Doctor of Philosophy at The University of Hong Kong in March 2007 End-point positioning accuracy, fast point-to-point motion travel and stable operation are essential in high-precision motion mechanisms for industrial applications such as semiconductor packaging. In this thesis, a high-precision 2-DOF planar parallel manipulator and a 4-DOF spatial parallel manipulator are developed to advance the motion capabilities of traditional XY table and overcome difficulties in the kinematics design and end-point positioning accuracy of existing parallel manipulators. Novel methods of kinematics design and optimization, dynamic modelling and advanced control strategies are integrated in a complete design of the proposed manipulators to achieve high-speed positioning of the end-effector to an accuracy of micrometer unit. Modular design approaches are developed for designing the kinematics structure of the proposed parallel manipulators. In this design process, consideration is given to ensuring that the kinematics design can be realized to the required tolerance using existing mechanical construction technology. A Monte-Carlo simulation method is developed to determine the workspace of the parallel manipulator, and a Jacobian decoupling approach is developed to verify that the workspace of the manipulator is free of internal singularity. Kinematics optimization is performed to suppress the kinematics error magnification effect so that the end-effector positioning accuracy matches the manufacturing tolerance of the linkages. A dynamic model is essential for motion analysis, capability estimation and controller design of the parallel manipulator. The derivation of the dynamic model is simplified using a nested approach whereby the 4-DOF parallel manipulator is decomposed into triangular mechanisms at the actuator level and at the end-effector level, resulting in a high degree of decoupling in the modelling process. Recursive Newton-Euler method is employed to determine the dynamic model. The response of the dynamic model is simulated using sinusoidal force profiles to drive the linear actuators of the manipulator. The results obtained from the kinematics design, optimization and dynamic modelling are used to develop prototypes of the planar and 4-DOF parallel manipulators for the purpose of experimentation. A traditional PID computed-torque controller is first designed for the 2-DOF planar and the 4-DOF parallel manipulators using a model-based approach. In view of the limitations of the computed-torque control method, a robust learning control method is developed to enhance the motion performance by minimizing the settling time and steady-state error of the parallel manipulators. A frequency-domain system identification approach is used to identify the high frequency dynamics of the manipulator. A robust control design method is employed to design a stable, fast tracking-response feedback controller with less sensitivity to high frequency disturbance, with the control parameters determined using genetic algorithm. A Fourier-series based iterative learning controller is added to the feedforward path of the controller to improve the settling time by reducing the dynamic tracking