工业机器人轨迹精度力-位置复合补偿方法

Force-Position Composite Control Method for Trajectory Accuracy Compensation of Industrial Robots

工业机器人关节刚度较低,在外负载干扰下加工精度较低,阻碍机器人在加工系统中的进一步推广和应用。为解决该问题,提出一种力前馈控制-位置反馈控制复合补偿方法,其中力前馈控制可超前补偿由外部负载力引起的位置偏差,位置反馈部分用于补偿机器人内部因素导致的位置偏差。利用六维力传感器和激光跟踪仪构建了轨迹误差在线补偿闭环控制系统,进行轨迹精度在线补偿试验,验证该方法的轨迹误差补偿效果。综合考虑机器人因内部参数和外部环境因素引起的误差,提高机器人的轨迹精度,能够实现机器人的精准控制。试验结果表明,该方法具有较强的鲁棒性,在外负载下依然可保持较高的轨迹跟踪精度,200 N冲击载荷下路径轨迹误差峰值为0.082 mm,稳态误差为0.047 mm,为复杂工况下高精度机器人加工奠定了基础。

The low joint stiffness of industrial robots and the low machining accuracy under the interference of external load have become the main obstacles to further promotion and application of robots in machining systems.A compound compensation method of force feedforward control and position feedback control is proposed to solve this problem.The force feedforward control part can compensate for the position deviation caused by external load force in advance,and the position feedback part is used to compensate for the position deviation caused by internal factors.A closed-loop control system for online compensation of trajectory error is constructed using a six-dimensional force sensor and a laser tracker.An online compensation experiment is carried out to verify the compensation effect of the proposed method.The errors caused by internal parameters and external environmental factors are considered comprehensively in the method,which improves the tracking accuracy of the robot and can realize the precise control of the robot.The experimental results show that the proposed method is robust and can maintain high trajectory tracking accuracy under large external loads.Under 200 N impact load,the peak error of path trajectory is 0.082 mm,and the stability error is 0.047 mm,which lays a foundation for high precision robot machining under complex working conditions.