具有线性位置解的3-CRU并联机器人轨迹跟踪

Research on trajectory tracking of 3-CRU parallel robot based on feedforward torque and sliding mode control

针对现有单一的线性伺服控制时机器人运动平台的跟踪轨迹精度较差的问题,基于前馈力矩补偿和滑模变结构控制相结合的控制策略,对具有线性位置解的3-CRU并联机器人的轨迹跟踪进行了相关研究.采用拉格朗日方程建立了该机器人的包含建模误差和外部干扰的动力学模型并辨识了机器人的动力学参数,设计了在线性伺服控制基础上前馈力矩补偿与滑模变结构控制相结合的控制策略.通过实验对比,证明采用上述控制策略不仅提高了机器人动平台的轨迹跟踪精度,而且增强了机器人系统的鲁棒性.同时,线性的位置正解方程这一特性使得机器人驱动滑块的位置误差传递到运动平台上不会呈指数型累积增长,从结构上保证了机器人运动平台的轨迹精度.

In view of the poor tracking accuracy of the moving platform of the robot when the existing linear servo control in the motor is used,the trajectory tracking of the 3-CRU parallel robot with linear position solution was studied based on the control strategy of the combination of feedforward torque compensation and sliding mode variable structure control.Firstly,the dynamic model of the robot including modeling error and external interference was established by using Lagrange equation and the dynamic parameters of the robot were identified.A control strategy combining feedforward torque compensation and sliding mode variable structure control based on linear servo control was designed.Through experimental comparison,the above control strategy not only improves the trajectory tracking accuracy of the robot,but also enhances the robustness of the robot system.At the same time,the linear positive position equation makes the position deviation of the actuated sliders transfer to the moving platform without exponential cumulative growth,which structurally ensures the trajectory accuracy of the moving platform.