Research On Advanced Sliding Mode Trajectory Tracking Control For A Wheeled Mobile Robot

In recent years, with the development of science and technology, intelligence robot technology has been deeply applied in all fields. In a sense, the application of intelligent robot technology represents the development of a country advanced productivity. Wheeled mobile robot has many advantages such as light weight, strong load capacity and quickly movement, which has showed great superiority in all aspects of human production and life. The problem of wheeled mobile robot tracking control has become a research hotspot. However, at present, wheeled mobile robot trajectory tracking control has been mostly applied in the two-dimensional plane. In other words, this constraint make it difficult to achieve three-dimensional inclined planes tracking control for the mobile robot. Therefore, research on three-dimensional trajectory tracking has great significance for the wheeled mobile robot. This thesis focuses on the problem of the wheeled mobile robot modeling and three-dimensional inclined planes tracking control based on advanced sliding mode method. Finally, the effectiveness of sliding mode control method is verified by the designed hardware platform.Firstly, based on the reconstruction model, nonholonomic wheeled mobile robot kinematics model and position equation are established in the two-dimensional plane and three-dimensional inclined planes.The backstepping method is used to design the switch function. Combining the advantages of backstepping control method with sliding mode variable structure control method, adaptive backstepping sliding mode control method is presented for the nonholonomic wheeled mobile robot on three-dimensional inclined planes. Compared with traditional PID control technology, the simulation results show that the backstepping sliding mode control method has better control precision and convergence speed. Further, a nonlinear disturbance observer is designed in order to estimate unknown external disturbance. Comparing with traditional backstepping sliding mode control technique, the numerical simulation results show that backstepping sliding mode control method based on disturbance observer weaken or eliminate the interference and guarantee accuracy of tracking control system to a certain extent.Secondly, a kind of fuzzy sliding mode three-dimensional trajectory tracking control method is presented for the nonholonomic wheeled mobile robot kinematics model. The presented method can eliminate or weaken the chattering in traditional sliding mode control. Compared with traditional PID control technology, the simulation results show that the fuzzy sliding mode control method has better control precision and convergence speed. Further, aiming at the fuzzy sliding mode control for nonholonomic wheeled mobile robot system disturbance problems, fuzzy sliding mode controller is designed based on disturbance observer. Numerical simulations have demonstrated the effectiveness of the proposed approach.Finally, wheeled mobile robot motion control system is developed based on sliding mode control method. Sliding mode control is used to realize DC motor speed control and simulation results show that it has better control performance than traditional PI control method. Indoor environment mobile robot experiment is realized by tracking S-shaped, U-shaped, O-shaped path previously marked out. Trajectory tracking results illustrate the good performance of sliding mode control method for mobile robot motion control system.