3-RRRU并联机器人运动学建模与误差分析

Kinematics Modeling and Error Analysis of 3-RRRU Parallel Manipulator

针对3-RRRU并联机器人控制精度问题,基于空间矢量法建立运动学正解模型以及误差模型,详细分析了机器人各结构误差源对控制精度的影响。仿真结果表明:驱动角度误差分布在0.001°~0.01°时,第一支链的驱动角误差对被控终端的精度影响最大为84.2um;连杆加工误差在0.01mm^0.1mm变化时,靠近动平台的被动杆为0.1mm时对被控终端精度影响最大,其最大误差值为137.2um;静、动平台的外接圆半径加工误差为0.1mm时,机器人终端最大误差为568.4um。因此,对于线性连杆加工误差和角度误差源,连杆加工误差对多支链、多连杆机器人精度的影响高于角度误差,且静、动平台的加工误差对机器人的终端控制精度影响最大,为后续机器人结构的最优化设计提供了理论依据。

Focusing on the control precision problem of the high speed 3-RRRU parallel manipulator,the kinematic forward solution model and the error model are established based on the space vector PWM,and the influence of the structural error source of the robot on the control precision is analyzed in detail. The simulation results show that when the driving angle error is(0.001~0.01)°,the first branch of the driving angle error influences the accuracy of the controlled terminal most,which is84.2μm. When the processing error of the rod is(0.01~0.1)mm,the accuracy of the controlled terminal is greatly affected by the passive rod near the dynamic platform,and the maximum terminal e rror is 137.2μm. When the processing error of the circumscribed circle radius of the static and dynamic platform is 0.1 mm,the maximum error of the controlled terminal is 568.4μm.Therefore,comparing the processing error source of the liner rod and the error source of the driving angle,the processing error of the liner rod has more influence on the accuracy of the branched and multi-rod robot than the driving angle error.Besides,the terminal control precision of the robot is greatest influenced by the processing error of the circumscribed circle radius of the static and dynamic platform. This study provides the theoretical basis for the optimal design of the robot structure.