Research On Trajectory Tracking Control Of Thrust Driven Mobile Robot

In a specific application environment,a thrust driven mobile robot with high mobility is needed to move autonomously along a given trajectory to complete some complex and dangerous tasks(such as reconnaissance,image return,etc.).Therefore,there are certain requirements for the trajectory tracking control accuracy of the robot.It is necessary to design a trajectory tracking control method to meet the task requirements,so as to achieve more accurate and effective control and further improve the ability of the robot to perform tasks.This paper focuses on the trajectory tracking control of the mobile robot.The main research contents are as follows:Firstly,based on the nonholonomic constraint theory,the nonholonomic constraint characteristics of the mobile robot are analyzed.The mathematical model of the mobile robot,including kinematic model and dynamic model,is established based on Euler Lagrange method and rouse equation,and its accuracy is verified by simulation analysis.Secondly,aiming at the trajectory tracking problem of the thrust driven mobile robot studied in this paper,without considering the internal and external disturbances of the system,a trajectory tracking controller based on the kinematic model is designed by using the inversion idea and the improved sliding mode variable structure method.In order to eliminate the chattering,the exponential approach rate is improved by using the hyperbolic tangent function.The stability of the system is analyzed by using Lyapunov stability theory,the stability of the closed-loop feedback system is proved,and the effectiveness of the designed kinematics controller is verified in the numerical simulation experiment.Thirdly,in the framework of double closed-loop feedback control,a trajectory tracking controller based on dynamic model is designed.The outer loop is the kinematics controller designed above,which outputs the virtual control speed;In the inner loop,the backstepping controller and sliding mode controller are designed respectively,and the output torque controls the virtual speed output by the kinematics controller.The stability of the control system is analyzed by using Lyapunov stability theory,the stability of the double closed-loop feedback control system is proved,and the effectiveness of the designed dynamic controller is verified in the numerical simulation experiment.Through analysis and comparison,it is concluded that the experimental tracking effect based on sliding mode controller is better.Finally,considering the influence of the total disturbance inside and outside the system on the trajectory tracking control effect,combined with the extended state observer technology of active disturbance rejection control technology,an adaptive sliding mode trajectory tracking control strategy based on robot dynamics model is proposed.An extended state observer is designed to estimate the total disturbance of the system in real time,and then the input of the dynamic controller is compensated to reduce the influence of the total disturbance of the system on the trajectory tracking effect of the robot.Simulation experiments are carried out for several typical trajectories to verify the feasibility and effectiveness of the control method designed in this chapter.