空间刚柔耦合并联机器人动力学求解策略  

Dynamic Solution for Spatial Rigid-flexible Parallel Robot

作　　者：刘凉[1] 赵新华[1] 周海波[1] 王嘉斌 

机构地区：[1]天津理工大学天津市先进机电系统设计与智能控制重点实验室,天津300384

出　　处：《农业机械学报》2018年第2期376-384,共9页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(51275353);天津市应用基础与前沿技术研究计划项目(17JCYBJC18300;14JCZDJC39100);天津市教委科研计划项目(2017KJ259)

摘　　要：针对空间刚柔耦合并联机器人在动力学方程求解过程中存在的违约问题,提出了一种基于瞬态刚体校正法的非线性动力学模型求解方法。利用自然坐标法和绝对节点坐标法构建该3-RRRU并联机器人的正动力学模型与逆动力学模型,考虑各支链柔性空间梁单元的剪切效应,并可描述其大范围非线性弹性变形。基于自然坐标法和刚性机构的运动学模型,分别提出2种动力学模型的瞬态刚体校正法,同时从系统能量等角度总结出获取该动力学系统稳定因果解的求解策略。仿真结果表明,动力学方程的求解精度为10-6,约束方程的相容误差为10-8,满足工程应用的要求,且有效地改善了动力学系统的综合收敛性能。通过圆形轨迹跟踪实验可知,与理想刚性模型的控制方法相比,基于逆动力学稳定因果解构建控制方法最大跟踪误差降低了0.372 mm,圆度误差降低了1.46 mm;各柔性杆上特征点处主应变测量值与理论计算值均处同一数量级,且具有相同的变化趋势,从而验证了该方法的有效性。In order to solve the compatibility problem occurred during the iteration for the dynamics of a spatial rigid-flexible parallel robot,a nonlinear solution approach was proposed based on a transient kinematic correction method. The nonlinear forward and inverse dynamics of a spatial 3-RRRU parallel robot with flexible links were constructed based on both natural coordinate formulation（ NCF） and absolute nodal coordinate formulation（ ANCF）. The derived models took into account the shear deformation and could describe large deformation for each beam. The transient kinematic correction methods were developed for the both dynamics based on NCF and kinematic model of the robot. The strategy for stable causal solution was also presented based on the aspects such as system energy of the dynamic system. The simulation results showed that the solution precision of inverse dynamics was 10-6 and the compatible error of constraints was 10-8,which met the requirements for engineering applications and could effectively improve the overall convergent performance for the dynamic system. A trajectory tracking experiment was carried out based on a prescribed circular trajectory. Compared with the control strategy on rigid dynamic model,the maximum tracking error and roundness error based on the provided control strategy were decreased by 0. 372 mm and 1. 46 mm,respectively. The calculated principal strains of the typical points on the flexible links were at the same levels and variation trends as the measured strains on them. The validity of the developed method was thus verified.

关 键 词：并联机器人 多体动力学 弹性变形 数值积分法 

分 类 号：TH113[机械工程—机械设计及理论]