Optimal Path Planning and Trajectory Tracking of Underactuated Robots

Optimal path planning and trajectory tracking of underactuated robots are investigated.The control target is to realize the arbitrary position control of joint angles.The controllability of underactuated robots is analyzed.The thought of partly stable controllers is introduced and the best switching sequence of partly stable controllers is obtained by using genetic algorithm.Sliding mode control method is utilized to realized accurate model tracking.The proposed method has following advantages:It does not make any hypothesis about the rigorous linearizations to the original nonlinear system.Also because of the global search ability of genetic algorithm,the optimal trajectory can be generated quickly and accurately.The accurate trajectory tracking can be guaranteed by the good adaptability to the disturbance and parameter changing of sliding mode control method.Therefore the proposed method can be used without modification for arms with a large number of degree of freedoms.At last numerical simulations are carried out on the planar 3R underactuated robot to verify the validity of the proposed method.