Optimization Design And Dynamic Control Of A2-DoF Planar Parallel Manipulator

This paper focuses on dynamic performance evaluation, optimization design anddynamic control of planar parallel mechanisms which can be used in high-speed hybridequipments. The purpose of this study is to improve the dynamic response ofhigh-speed parallel mechanisms. Details are as follows:Based on the characteristic of the kinematic and stiffness performances of parallelmechanisms, the method of evaluating those performances is investigated. The indiceswhich can evaluate kinematic and dynamic performances and have been used inoptimization design of parallel mechanisms are selected. For the purpose of morecomprehensive description of the performances, the corresponding variance indices areintroduced as supplements to describe the trend of the performances.Based on the factors in the acceleration performance function, the effect on theacceleration performance of parallel mechanisms is investigated. Then a new methodfor dynamic performance evaluation of parallel mechanisms is introduced. The effect ofthe speed factor, gravity factor and external force factor on the acceleration performanceis considered in the new method. So it can evaluate the dynamic performance ofhigh-speed parallel mechanisms more exactly. Based on this method, the evaluationindices used in dynamic optimization are introduced. These indices overcome thelimitation of commonly used indices, and lay the foundation for dynamic optimizationof parallel mechanisms.A multi-objective optimization method is introduced to the multi-performanceoptimization of parallel mechanisms and successfully applied in the design of the planarparallel mechanism. In the optimization method, the kinematics, stiffness and dynamicperformances of the parallel mechanism are improved by optimizing the key geometricand structural parameters of the parallel mechanism. The design results indicate that theoptimization method is of practical value to improve the development of the dynamicoptimization of parallel mechanisms.For the purpose of improving the dynamic response of the high-speed parallelmechanisms, a dynamic feedforward control method which can inhibit the disturbancefrom external force is introduced. The simulation results indicate that not only the blightto the dynamic response of dynamic performance of high-speed parallel mechanisms is decreased but also the effect on the precision of the disturbance of external force in themaking process is impaired. Finally, the relevant experiments on the dynamic control ofthe prototype of2-PRR parallel mechanism are given. The experiment results indicatethat the control method is effective.