3-PRS并联机构的动力学惯量耦合特性分析

Dynamic inertia coupling characteristics analysis of 3-PRS parallel mechanism

针对3-PRS并联机构动力学惯量耦合特性的问题,在关节空间中建立了机构的动力学模型,对机构主动支链之间存在的惯量耦合进行了研究。首先,给出了机构的运动学模型,针对动平台广义位姿、速度、加速度存在耦合的问题,分别通过约束方程、一阶影响系数矩阵、二阶影响系数矩阵,对其进行了解耦,并建立了各支链与动平台末端速度、加速度的映射关系,对机构运动学进行了仿真验证;其次,采用虚功原理建立了机构的动力学模型,并进行了仿真验证;然后,建立了机构在关节空间的动力学模型;最后,在机构的工作空间内,研究了惯量耦合特性评价指标随机构运动的分布规律。研究结果表明:在机构的工作空间内,在一定程度上,通过合理规划机构的运动范围,可以减小并联机构主动支链间的动力学惯量耦合强度。

Aiming at the problem of inertia coupling characteristics of 3-PRS parallel mechanism,the dynamic model of 3-PRS parallel mechanism was established in joint space,and the inertia coupling between active branches was studied.Firstly,the kinematics model of mechanism was given.Aiming at the coupling problem of generalized pose,velocity and acceleration of moving platform,it was decoupled by constraint equation,first-order influence coefficient matrix and second-order influence coefficient matrix respectively.The relationship was established of velocity and acceleration between branches and moving platform.The kinematics model was verified by simulation.The dynamics model of mechanism was established by virtual principle and verified by simulation.Then,in the joint space,the dynamics model of mechanism was established.Finally,the change of the evaluation index of inertia coupling characteristics with the motion of the mechanism was studied in the workspace of the mechanism.The results show that the inertia coupling strength of dynamics between the branches can be reduced,and the influence on the dynamic performance of the mechanism can be reduced by properly planning the kinematic space of the mechanism.