一种基于相邻耦合误差分析的非线性PD偏差耦合同步控制方法

摘要

为了提高六自由度轻量型机器人的轨迹跟踪精度同时减小其同步误差,提出一种基于相邻耦合误差分析的非线性PD偏差耦合同步控制方法.建立并验证了该机器人的数学模型,包括运动学模型、动力学模型以及样条轨迹规划.因为难以描述复杂轨迹下的机器人实时轮廓误差,因此本文引入相邻耦合误差来解决这一问题.结合机器人非线性控制以及耦合特性,设计了非线性PD偏差耦合同步控制器,并通过仿真分析进行验证.伺服控制试验系统由激光跟踪系统、机器人机械系统以及基于EtherCAT通讯的伺服控制系统构成,实验数据表明,该控制方法可使机器人同步误差大幅度减小,并且最大跟踪误差由0.33 mm缩减到0.1 mm.实验结果验证了控制算法的有效性,从而证明了该控制策略能够有效改善机器人的轨迹跟踪精度.%In order to improve the trajectory tracking precision and reduce the synchronization error of a 6-DOF lightweight robot, nonlinear proportion-deviation (N-PD) cross-coupling synchronization control strategy based on adjacent coupling error analysis is presented. The mathematical models of the robot, including kinematic model, dynamic model and spline trajectory planing, are established and verified. Since it is difficult to describe the real-time contour error of the robot for complex trajectory, the adjacent coupling error is analyzed to solve the problem. Combined with nonlinear control and coupling performance of the robot, N-PD cross-coupling synchronization controller is designed and validated by simulation analysis. A servo control experimental system which mainly consists of laser tracking system, the robot mechanical system and EtherCAT based servo control system is constructed. The synchronization error is significantly decreased and the maximum trajectory error is reduced from 0.33 mm to 0.1 mm. The effectiveness of the control algorithm is validated by the experimental results, thus the control strategy can improve the robot's trajectory tracking precision significantly.