Research On The Uncertantity Control Of Wheel Mobile Robot In Complex Environment

The wheeled mobile robot have been widely used in our daily life,and due to the uncertain factors in practical environment,the control system of the wheeled mobile robot may be affected,and then even cause the control system to be unstable,then will reducing the system control accuracy.The non-holonomic wheeled mobile robots control system is typical multi-input and multi-output coupled under-actuated nonlinear systems,so general smooth state feedback can't be applied to such nonlinear systems.Therefore,the research on the motion control of non-holonomic wheeled mobile robots with uncertainties is of great significance.Firstly,the research background and significance of the topic are elaborated,and the research status of the motion control strategy of uncertain wheeled mobile robot in complex environment is analyzed.The non-holonomic constraints of wheeled mobile robots are introduced,and the kinematics and dynamics models of the robot are modeled and analyzed.Secondly,the disturbance observer is used to deal with the uncertainty occurring in the system,regardless of the slippage of the wheel and considering that the robot is interfered by uncertain factors.Based on the disturbance observer,the kinematics and dynamics controllers are designed separately.The disturbance observer and the kinematics virtual controller are independent of each other.When the control system encounters interference,the control input is compensated by the output feedback of the disturbance observer.Finally,the simulation results show that the disturbance observer based torque control algorithm improves the trajectory tracking error by 11.428% compared with the kinematics based algorithm.Then,an adaptive control strategy is proposed again for the case where only longitudinal sliding occurs during the motion of the robot.Based on the kinematics model,the virtual speed controller is designed,then the sliding parameters are introduced,combined with the auxiliary control input,the sliding parameter adaptive updating law is designed,the sliding parameters of the left and right wheels are updated online,and the Lyapunov stability theorem is utilized.Prove the stability of the method.The simulation results show that the proposed adaptive sliding mode control method reduces the tracking error by 1.000% compared with the dynamic model based control algorithm.At last,the auxiliary controller is designed based on the kinematics and dynamics model.The disturbance observer can estimate and compensate the sliding or skidding parameters of the wheeled mobile robot during the motion in real time,so that the actual running speed of the robot gradually converges.The simulation results show that the tracking effect of the sliding mode control algorithm based on the disturbance observer is improved compared with the sliding mode control algorithm.The accuracy of the left and right trajectory tracking is improved by 2.981% and 4.315% respectively.