带有未知参数和有界干扰的移动机器人轨迹跟踪控制

Trajectory tracking control for nonholonomic mobile robots with unknown parameters and bounded disturbance

针对模型参数未知和存在有界干扰的非完整移动机器人的轨迹跟踪控制问题,本文提出了一种鲁棒自适应轨迹跟踪控制器方法.非完整移动机器人的控制难点在于它的运动学系统是欠驱动的.针对这一难点,本文利用横截函数的思想,引入新的辅助控制器,使得非完整移动机器人系统不再是一个欠驱动系统,缩减了控制器设计的难度,进而利用非线性自适应算法和参数映射方法构造李雅谱诺夫函数.通过李雅普诺夫方法设计控制器和参数自适应器,从而使得非完整移动机器人的跟随误差任意小,即可以任意小的误差来跟随任意给定的参考轨迹.仿真结果证明了方法的有效性.

The trajectory tracking control problem for a nonholonomic mobile robot with unknown system parameters and bounded external disturbances is investigated and a robust adaptive tracking control scheme is proposed in this paper. The main difficulty of tracking control of a nonholonomic mobile robot is that the kinematics is underactuated. To deal with this difficulty, an additional controller variable is created through variable transformation by using the traverse function method. With the additional control variable, the kinematic model of the nonholonomic mobile robot is no longer underactuated, thus, facilitating the control design for the nonholonomic mobile robot extensively. Finally, nonlinear adaptive control and parameter projection techniques are adopted to derive the tracking controller and parameter estimator through the Lyapunov function approach. It is shown with rigorous proof that with our proposed control scheme, the reference trajectory can be followed globally with an arbitrarily small tracking error. Simulation results also demonstrate the effectiveness of our proposed controller.