轮式移动机器人预定时间轨迹跟踪控制

Predefined time trajectory tracking control of wheeled-mobile robot

在现有的轨迹跟踪控制中,跟踪误差的收敛时间通常与误差初始值有关,且关于非完整系统预定时间轨迹跟踪的控制方法很少.针对上述问题提出了一种使非完整轮式移动机器人系统可在预定时间跟踪上参考轨迹的控制方法.首先,通过坐标变换,将跟踪误差系统转变为一个由角度误差构成的一阶子系统和一个由位置误差构成的二阶子系统;然后,分别针对角度误差系统和位置误差系统设计机器人的角速度输入和速度输入,使得角度误差和位置误差在预定时间内收敛到零;最后,利用Lyapunov方法证明了所设计控制律的有效性.试验结果表明,提出的控制方法可使机器人在预定时间跟踪上参考信号,且实际收敛时间与理论计算时间相同,比现有的控制方法更加精确.

In the existing trajectory tracking control,the convergence time of the tracking error is usually related to the initial value of the error,and there are few results on the predetermined time trajectory tracking of nonholonomic system.To solve the above problems,a control method that ensures the nonholonomic wheeled mobile robot system to track a reference trajectory at a predetermined time is proposed.First,through coordinate transformation,the tracking error system is transformed into a first-order subsystem composed of angular errors and a second-order subsystem composed of position errors.Then the angular velocity and the speed of the robot are designed for the angle error system and the position error system respectively,which can force the angle error and position error converge to zero within a predetermined time.Finally,the Lyapunov method is used to prove the effectiveness of the designed control law.Numerical simulation shows that the proposed control method can make the robot track the reference trajectory at a predefined time,the real time for the robot to track the reference and the calculated convergence time is equal,and the convergence time is more accurate than that in existing control method.