基于参考轨迹实时修正的机器人轨迹跟踪控制方法

针对动力学不确定性的机器人轨迹跟踪问题,本文提出一种基于参考轨迹实时修正的机器人轨迹跟踪控制方法。将轨迹跟踪中已产生的误差进行累加,实时前馈补偿到参考轨迹上即将被跟踪的点上。给出了该方法的控制框图,由控制框图导出跟踪误差与命令误差之间的关系式。关系式表明只需控制器中的控制算法保证速度误差稳定,即可保证跟踪误差收敛。此外,提高补偿增益的值可以提高误差的收敛速度。分析PD控制律能满足所提方法的收敛条件。给出了所提方法中参数的调节方案。通过仿真和实验验证了该方法的有效性。实验结果表明,各个关节跟踪轨迹1得到的误差绝对值均不大于0.008 7 rad;跟踪轨迹2得到的误差绝对值均不大于0.005 9 rad。

Robot Trajectory Tracking Control Based on Reference Trajectory Real-time Modification

A simple and effective control method for robot trajectory tracking with uncertain dynamics was presented. The core idea of the proposed method was to modify the reference trajectory in real-time. The main operation of this method was to accumulate the generated tracking errors and compensate them feedforward in real-time to the points to be tracked on the reference trajectory. Firstly, the control block diagram for the proposed method was showed. Then, the equation for the relationship between the tracking error and the command error was derived from the control block diagram. The equation showed that the control algorithm in the controller only needed to ensure that the velocity error was stable and the tracking error would converge. The increase in compensation gain can also accelerate the convergence of the error. Subsequently, the convergence condition that PD control law can satisfy the proposed method was analyzed. At the same time, the adjustment scheme of parameters in the proposed method was given. Finally, the effectiveness of the proposed method was verified by simulation and physical experiment. In the physical experiment, the absolute value of error obtained from tracking trajectory 1 of each joint was no more than 0.0087rad; the absolute value of error obtained from tracking trajectory 2 of each joint was no more than 0.0059rad.