Research On Trajectory Tracking Control Of Nonholonomic Wheeled Mobile Robots

With the advancement of technology and the improvement of social needs,mobile robots have played an important role in many fields of human society,which have great research value broad application prospects.As a typical nonholonomic control system,the researches of mobile robot have been popular with the majority of scholars,and trajectory tracking control is the most significant one.In this thesis,a wheeled mobile robot(WMR)is investigated,which includes its control system design and trajectory tracking control.The main contributions of the thesis are as follows:1.The nonholonomics of wheeled mobile robot is analyzed based on theories of nonholonomic restriction and nonholonomic control system.The kinematics model of WMR is established by nonholonomic restriction analysis,and then the leader-follower error model is presented of multiple WMR(multi-WMR)system,which lays a foundation for the following experiments.2.A WMR platform is constructed using Arduino Mega 2560 controller as the core,and the communication between modules is implemented under the environment of Arduino IDE.Moreover,a closed loop speed control system is constructed,as well as its software structure,which implements the primary function of modules.The motor speed control experiments are developed,which demonstrate the effectiveness of closed loop speed controller and the feasibility of WMR control system.3.Consider the multi-WMR trajectory tracking control problem,a multivariable decoupling control method is presented based on the leader-follower error model.In order to ensure the stability,a trajectory tracking controller is presented through classical PID control method.Given the limitations of classical PID controller,a nonlinear PID trajectory tracking control algorithm with multivariable decoupling strategy is proposed,including the enhancement of classical PID controller by nonlinear tracking differentiator.4.A multi-WMR trajectory tracking control experiment platform is constructed by two WMR systems,and the software system is developed under the environment of robot operating system(ROS).Then relevant experiments are developed to show the performance of the proposed algorithm,including the comparison with PID controller.The experimental results demonstrate the effectiveness and robustness of the algorithm.5.The summary and prospect of this paper are provided.