Study On The Adaptive Sliding Mode Trajectory Tracking Control Of Nonholonomic Mobile Robot

In recent years, the trajectory tracking problem of the nonholonomic mobile robot has been widely studied. Based on the kinematics and dynamics model of the mobile robot, this thesis researches on the application of the sliding mode control, the adaptive control and the backstepping method in the trajectory tracking controller design. The main work and accomplishment of the thesis includes:(1) The nonholonomic characteristic of the wheeled mobile robot is analyzed, the kinematics model and dynamics model is established by using the coordinate transformation method and the Lagrange method. At last the feasibility of the trajectory tracking is proved.(2) Based on the kinematics model of the nonholonomic mobile robot, the method of non-dither sliding mode trajectory tracking controller is designed by taking the linear speed and the angular speed of the mobile robot as the control inputs. When the kinematics model exists the unknown parameters, the adaptive sliding mode trajectory tracking controller method is presented by taking the angular speed of two driven wheels as the directly control inputs. The simulation result proves the correctness of the design method.(3) Based on the dynamics model of the nonholonomic mobile robot, a global asymptotically stable tracking controller is designed using backstepping technique and adaptive sliding mode control method even in the presence of unknown parameters and bounded uncertainties. This method breaks down nonlinear systems into low dimensional systems and simplifies the controller design using virtual control inputs and partial Lyapunov functions. The control law has the strong robustness and is proved the correctness with the simulation result.(4) The terminal sliding mold trajectory tracking controller based on the kinematics model of nonholonomic mobile robot is designed. If the reference trajectory has a non-zero angular speed, then this method can completely track the trajectory in the finite time. Based on the dynamic model of nonholonomic mobile robot, a fast terminal sliding mode tracking controller which combines the backstepping method and the thought of the fast terminal sliding mode control is presented to track the desired trajectory in finite time.