Feedback Stabilization And Trajectory Tracking Control For Wheeled Mobile Robot With Nonholonomic Constraints

With the social development and progress of science and technology, the technology andsystem research of mobile robot attract more and more attention, and have been applied tomany fields, such as industry, agriculture, national defense, service and so on. The mobilerobots are capable of performing some disgusting, heavy or harsh tasks historically assignedto human beings. As for mobile robot, the autonomous navigation and motion controltechnology is the key of achieving the intelligence of mobile robot which have significanttheoretical value and engineering application value. In this dissertation, we mainlyconcentrate on feedback stabilization and trajectory tracking for wheeled mobile robots. Byemploying sliding mode variable structure and terminal sliding mode variable structurecontrol method, the novel feedback stabilization and trajectory tracking laws based onkinematic and dynamic model respectively are proposed to improve the accuracy of trajectorytracking for the wheeled mobile robot. The main research work and contributions of thedissertation are summarized as follows:1. By analyzing the nonholonomic constraint and nonholonomic properties of wheeledmobile robot, the kinematic model and dynamic model are established for mobile robot withtwo independent driven wheel angular velocities and ideal constraint. This model can beapplied for the research purposes and foundation of feedback stabilization and trajectorytracking control.2. In order to realize the requirement of feedback stabilization for mobile robot, thekinematic model is converted into the drift-free chain system for mobile robot. Then, thediscontinuous feedback and limited time feedback stabilization control laws are designed toby using potential linear structure, subsystem decoupling and subsection control strategy ofchain system.3. For kinematic model of nonholonomic mobile robot, the sliding mode and terminalsliding mode variable structure control laws are present to realize the trajectory tracking byemploying backstepping method and sliding-mode control technology. When the expectedlinear velocity is not equal to zero, the requirements of trajectory tracking in finite time canbe realized. The simulation results show the effectiveness and correctiveness of the proposed control law.4. By employing the sliding mode and non-singular terminal sliding mode controlapproach and introducing speed control vector into torque control of dynamic model, theglobally trajectory tracking law in finite time is designed for dynamic model ofnonholonomic mobile robot. Simulation results verify the correctness and effectiveness of theproposed method.