2-TPR/2-TPS并联机构的精密运动控制

Precision motion control of 2-TPR/2-TPS parallel mechanism

在传统PID控制下,电机驱动的2-TPR/2-TPS并联机构因负载变化会引起末端轨迹跟踪精度较低。因此,文章提出了伺服电机速度环模糊PID控制和位置环P控制结合的双闭环控制方法。针对变负载系统的切换PID控制器和增量式自适应模糊PID控制器,搭建了基于SIMSCAPE的Electronics-Multibody联合仿真控制系统,并对3种控制策略下的动平台末端轨迹和驱动支链位移误差进行了对比分析。仿真结果表明,针对2-TPR/2-TPS并联机构的变负载特性,变PID控制策略下的动平台轨迹跟踪精度更高;相对于分段PID控制,自适应模糊PID控制具有更优的动态性能和更高的末端轨迹跟踪精度。

The end trajectory tracking accuracy of the motor-driven 2-TPR/2-TPS parallel mechanism under traditional PID control is low due to load changes.Therefore,a double closed-loop control combining servo motor speed loop fuzzy PID control and position loop P control is proposed.Based on the trajectory planning of the end of the moving platform and the analysis of the branch chain driving torque,the switching PID controller and the incremental adaptive fuzzy PID controller for the variable load system are designed,and the Electronics-Multibody joint simulation control system based on SIMSCAPE is built.A comparative analysis of the displacement error of the end trajectory of the moving platform and the driving branch chain under the three control strategies is carried out.The simulation results show that for the variable load characteristics of the 2-TPR/2-TPS parallel mechanism,the trajectory tracking accuracy of the moving platform under the variable PID control strategy is higher.Compared with the segmented PID control,the adaptive fuzzy PID control has better dynamic performance and higher end trajectory tracking accuracy.