Research Of Optimization Design And Dynamic Control Of A 2-DOF Planar Parallel Mechanism

The lower mobility parallel mechanism which has advantages on simple structure and easy to control and economy is more and more widely applied in engineering application.When the configuration of the parallel mechanism is determined,the choice of design parameters and control strategy has a significant impact on its performance.A two degree of freedom(2wDOF)planar parallel mechanism which is employed in the hybrid machine tool was studied.The performance evaluation and optimization design and dynamic Control of the parallel mechanism were discussed in-depth.Details are as follows:The kinematical model of the parallel mechanism was established with analytical method.The inverse and forward kinematics and Jacobin matrix were carried out.The singularity and velocity and acceleration were analyzed and the workspace was discussed.Based on the stiffness matrix method and kane method the stiffness and dynamic mode was derived.The dynamics analytic calculation was acquired by MATLAB programming.The correctness of the dynamic mode and analytic calculation were verified by the ADAMS virtual simulationThe global performance evaluation indexes of the kinematic and dynamic and stiffness performances of the 2-DOF planar parallel mechanism were established.The multi-parameter optimization design of the parallel m,echanism was accomplished by using the Muti-objective optimization algorithm which called Non-dominated sorting genetic algorithm(NSGA-?)to improve the kinematic and dynamic and stiffness performances.For the dynamic control of the 2-DOF planar parallel mechanism,the typical controllers which were so-called Augmented PD control and computed torque control were designed.The trajectory.racking ability was compared the Augmented PD contol with the computed torque control.To the problem of inaccuracy dynamic model in practical engineering,the corresponding parts were compensated by the RBF neural network and the adaptive control which had a good control effect of the parallel mechanism was achieved.