Delta并联机械手刚体动力学模型简化方法

摘要

A complete rigid body dynamic models is established based on the virtual work principle,and the components of the dynamic models,i.e.the inertia moment term,the inertial force term and gravity term,are classified.After analyzing the slave arm movements on the contribution of the components of the manipulator torques,a simplified strategy for the rigid body dynamic models based on combinatorial mass distribution coefficients is presented;The degree of approximation between the simplified and complete models is introduced as an optimization objective,and an optimization index for minimizing the torque deviations between the two models during the motion of the manipulator is formulated in order to determine the combinatorial mass distribution coefficients;Based on the simplified method and considering the length and movement trajectory parameters of the manipulator,simulation of the parameters influence on the accuracy of the simplified models is implemented with the multi-factor analysis method,and the results show that the simplified models has higher computation speed and accuracy for different the length and movement trajectory parameters.%基于虚功原理建立了机械手的完备刚体动力学模型,并对机械手动力学模型的各组成部分(惯性力矩项、惯性力项和重力项)进行了分类;在分析从动臂的运动对机械手力矩各组成部分贡献的基础上,提出了一种基于组合分配系数的刚体动力学模型简化策略;以简化刚体动力学模型与完备刚体动力学模型逼近度为优化目标,提出一种基于运动过程力矩偏差最小的优化指标,从而确定组合分配系数;基于以上刚体动力学简化方法,从机械手尺度参数与运动轨迹参数两方面因素出发,结合机械手典型运动轨迹,采用多因素分析方法,通过仿真分析了各因素对简化刚体动力学模型准确性的影响,结果表明该刚体动力学模型简化方法针对不同机械手尺度参数与运动轨迹参数均具有较高的计算速度和精度.