关键词: 4-RR(RR)R并联机构, 动力学性能指标, 模型仿真, 影响系数矩阵

Abstract: The spatial configuration of a novel 4-RR(RR)R parallel mechanism is analyzed by using the position inverse solution, and Jacobian matrix and Hessian matrix are established by adopting the methods of virtual mechanism and influence coefficient matrix. Then Hessian matrix is introduced into the global performance index, which is different from only adopting Jacobian matrix as the performance evaluation index in the past, thus the evaluation of dynamic characteristics of mechanism is more comprehensive. The velocity, acceleration and inertial force performances of the 4-RR(RR)R mechanism are analyzed, and three performance atlases are given. Furthermore, the mechanism dimensions are changed, and the work spaces of the mechanisms with different dimensions are searched. Then the influence of change of mechanism dimensions on the mechanism performance is discussed within the range of accessible work space. Emphatically, The extent of influence of Jacobian matrix and Hessiag matrix on the acceleration of mechanism is discussed. Through the comparison of the concrete numerical values of acceleration deviation, it is found that the Hessian matrix has more important influence on the acceleration performance of the mechanism. Finally, Matlab software is used to carry out model simulation for the mechanism.

Key words: 4-RR(RR)R parallel mechanism, Dynamics performance indices, Influence coefficient matrix, Modeling simulation