轮式多机协同搬运机器人轨迹跟踪控制器设计

Trajectory Tacking Controller Design for Wheeled Robots in Multi-robot Cooperative Transport

轮式移动机器人多机协同搬运负载过程中受到的地面非完整约束以及负载刚性约束,对其轨迹跟踪控制器的动态特性以及稳态误差均提出很高的要求。基于李雅普诺夫第二方法,设计轮式移动机器人渐进稳定轨迹跟踪控制器,实现输入饱和约束可沿广义速度空间边界滑动,在保证控制信号不超出机器人广义速度空间的前提下,提升轨迹跟踪控制器的响应速度。研究轨迹跟踪控制器对不同目标轨迹的跟踪误差规律,提出以门限角度为分界的状态机,控制机器人对目标参数的响应顺序,减小跟踪过程误差。基于模糊控制器,实现轨迹跟踪控制器增益系数的动态调节,有效降低对不同目标速度的跟踪稳态误差。通过多机协同搬运负载试验验证控制器的正确性和有效性。

The multi-robot cooperative transport is subject to non-holonomic constraints and load rigid constraints,which put forward high requirements on the dynamic characteristics and steady-state error of its trajectory tracking controller.Based on Lyapunov’s second method,an asymptotic stable trajectory tracking controller for a wheeled mobile robot is designed,which realizes that the control input saturation constraint can slide along the boundary of the generalized velocity space and improves the response speed of the trajectory tracking controller within the robot’s generalized velocity space.The tracking error law of different target trajectories is studied,and a state machine with a threshold angle as the boundary is proposed to control the response sequence of the robot to the target parameters and reduce the error of the tracking process.Based on the fuzzy controller,the dynamic adjustment of the coefficient items of the trajectory tracking controller is realized,which effectively reduces the tracking steady-state error for different target speeds.The correctness and effectiveness of the controller are verified by multi-robot cooperative transport experiments.