Motion Control Of The Self-Balancing Two-Wheeled Vehicle

In recent years, with the rapid development of the city construction, the problems of traffic congestion and automobile exhaust pollution become increasingly serious. In this context, the self-balancing two-wheeled vehicle gains more popularity as an electricity-driven transport. This novel vehicle owns broad application prospects in the fields of civilian and military because of its small size, simple structure, self-balance property and flexible operation within confined space. Scholars from home and abroad start to do research on the mathematical modeling, control algorithm as well as mechanical structure design of the self-balancing two-wheeled vehicles. PID control, fuzzy control, sliding mode control and neural network control methods are employed on the self-balancing two-wheeled vehicles and the effectiveness of these control algorithms are validated. However, existing literature seldom takes straight-driving and turning compound control into consideration.In this paper, the mathematical model of the self-balance two-wheeled vehicle is established in terms of the Lagrange equation. The feasibility of the model is validated by MATLAB/Simulink. The straight-driving and turning dynamic structures of the self-balancing two-wheeled vehicle are deduced. The straight-driving dynamic structure of the vehicle is similar with the linear inverted pendulum. As a result, the straight-driving control method of the vehicle can be designed according to the double-loop control method. The observability and controllability of the self-balancing two-wheeled vehicle is analyzed. The double loop PID controller of the self-balancing two-wheeled vehicle is derived as well. The inner tilt angle loop utilizes PD controller, while the outer velocity loop uses PI controller. The effectiveness and robustness of the controllers are verified by MATLAB/Simulink.The straight-driving and turning controllers are designed respectively to avoid complicated decoupling problems. The symmetric coupling property of the system is analyzed. The PI controller is employed on the turning loop based on the dynamic structure. In order to realize motion in two dimensional plane, the straight-driving and turning compound control system is designed on the basis of the symmetric coupling property. The effectiveness of the compound controller is validated by MATLAB/Simulink.