Research On The Tracking Of Mobile Robots Based On Sliding Mode Control

In recent years,the control problem of non-holonomic systems has been a hot topic of research.As a typical non-holonomic system,mobile robots are widely used for industrial,military,scientific and commercial purposes.The control problem has attracted wide attention in the academic community.Due to the uncalibrated parameters,the existence of external disturbances,and the uncertainties of measurement and unmodelled dynamics,it is difficult to obtain an accurate kinematic model of a robot system in practice,which brings great difficulties to research.Some scholars at home and abroad have put forward a variety of methods to solve this problem,which has brought great convenience to our research.This thesis mainly studies the tracking control problem of mobile robot system and the coupling trailer system.Firstly,this thesis introduces the background,significance,present situation and prospect of mobile robot,introduces the concept of non-holonomic systems and control principle of non-holonomic systems,and gives the kinematics and dynamics model of mobile robot.In addition,the basic theory of sliding mode control is introduced in detail.A hybrid algorithm based on back-stepping control and non-singular terminal sliding mode control is presented for tracking control problem of mobile robot with one centrifugal wheel and two fixed wheels.This algorithm can realize the finite-time tracking of the optimal speed and eliminate the jitter problem in sliding mode control.In addition,two controllers,the adaptive equivalent sliding mode controller and the adaptive exponential reaching law sliding mode controller,are designed for the tracking control problem of the coupling trailer mobile robot under the video camera.It can be obtained by comparison that the exponential reaching law sliding mode control can reduce the jitter and converge to the sliding mode surface faster than the equivalent sliding mode control.The simulation results show that the controllers are effective.There are two innovations in this thesis.First,a hybrid algorithm is proposed to solve the tracking control problem of mobile robots.This algorithm can realize the finite-time tracking of the optimal speed,and the jitter in sliding mode control can be eliminated.Second,the sliding mode control is used to solve the tracking control problem of the coupling trailer system when the camera parameters α1 and α2 are unequal,unknown and θ0 is unknown.