Trajectory Tracking Control Of Nonholonomic Mobile Robot Based On Decoupling And H_∞ Robust Strategy

Nonholonomic constraint means that the constraint equation contains the time derivative of the systematic generalized coordinates, which are not integrable. As a typical model of the nonholonomic system, the nonholonomic characteristic of wheeled mobile robot arises from the wheel which is rolling without slipping.A new model of the wheeled mobile robot called difference driven model is proposed in this thesis. The wheels of the single side are same velocity through the synchronized dentiform belt. This kind of structure is simple and advanced. Its motion is steady and reliable. The energy is utilized in the way of high efficiency. The design of its controller is relatively simple. The kinematic and dynamic models are constructed by nonholonomic mechanics. After that, its nonholonomic speciality is deeply analyzed. The controllability of the trajectory tracking has been proved.Aimed at trajectory tracking of the mobile robot, the decoupling strategy is proposed according to the kinematic equation. The effectiveness of the controller is shown through the simulation. This algorithm is lack of anti-disturbance. With the practical consideration, a hybrid strategy of decoupling and H∞robust is proposed. The robotic dynamic model including both uncertainty itself and outside disturbance is firstly constructed. Then the state equation of generalized error is transformed by input/output decoupling. According to the H∞performance, the hybrid algorithm is established. And it is proved to be asymptotical stability. The effectiveness is demonstrated through the simulation of tracking the desired elliptical trajectory.Finally, the mechanical body of the mobile robot is designed specifically. The whole hardware framework is constructed. A reference platform is established for a further experimental verification of the algorithm.