针对轮式移动机器人在车轮打滑情况下的轨迹跟踪控制问题,提出了一种利用线性扩张状态观测器(Linear Extended State Observer,LESO)和积分滑模面的控制方案.首先,根据车轮打滑情况下的非完整约束条件建立轮式移动机器人的运动学模型.根据动能函数和拉格朗日方程建立其动力学模型.将这两种模型相结合得到力矩与速度相关的数学模型.其次,利用LESO对该数学模型进行扩张,并对总扰动进行估计.基于实际速度与虚拟速度之差设计带有积分项的滑模面,将扰动估计值前馈结合滑模面设计动力学控制器,并给出速度跟踪误差在有限时间内收敛的证明.最后,与基于超螺旋干扰观测器设计的控制方案仿真相比,所提出方案角速度跟踪误差在1 s左右时已趋于零,车轮力矩值稳定在3 N·m左右,且无锯齿抖动,扰动误差在1～5 s时波动更小,5～20 s时未出现明显锯齿抖动,仿真结果表明所提方案跟踪效果更好,抗干扰能力更强,观测精度更高.
Sliding Mode Trajectory Tracking Control of Wheeled Mobile Robot Based on LESO
Aiming at the trajectory tracking control problem of wheeled mobile robots under the condition of wheel slipping,a control scheme consisting of linear extended state observer(LESO)and integral sliding mode surface has been proposed.First of all,the kinematics model of the wheeled mobile robot is established according to the nonholonomic constraints under the condition of wheel slipping.And the dynamic model of the wheeled mobile robot is established according to the kinetic energy function and Lagrange equation.A mathematical model for wheel torque and speed can be derived by combining these two models.Secondly,the mathematical model is expanded by using LESO,and the total disturbance is estimated.The sliding mode surface with an integral term is designed from the difference between the actual speed and the virtual speed.The dynamic controller is designed by combining the disturbance estimation feedforward with the sliding mode surface and the convergence of velocity tracking error in finite time is proved.Finally,the proposed scheme is compared with the simulation of the control scheme based on the super-twisting disturbance observer.The simulation results show that the angular velocity tracking error of the proposed scheme tends to zero curve when it is about 1 s.The wheel torques are stable at about 3 N·m,and the waveforms have no sawtooth jitter.The disturbance error fluctuates less within 1～5 s,and there is no jitter in the waveform within 5～20 s.The simulation results show that the proposed scheme has better tracking effect,stronger anti-interference ability and higher observation accuracy.
wheeled mobile robottrajectory trackingwheel slippinglinear extended state observersliding mode control
国家科技期刊平台
NSTL
万方数据
维普
