Finite-time Trajectory Tracking Control Of Pneumatic Muscle Actuator

Rehabilitation robots can perform tedious work in rehabilitation processes for physical therapists,which can reduce labor costs.Pneumatic artificial muscle is widely used in rehabilitation robots,due to its similar properties to human muscle.Specific rehabilitation training needs to be provided to the patients in the rehabilitation processes based on their physical condition,which can be reduced to a trajectory tracking control problem.Therefore,it can be accomplished by the trajectory tracking of the pneumatic artificial muscle-driven rehabilitation robots.The strong uncertainties and the complex nonlinear characteristics of pneumatic artificial muscle make it difficult to achieve high-precision control of pneumatic artificial muscles.This thesis aims to studying finite-time control algorithms of the pneumatic artificial muscle.In this thesis,the pneumatic artificial muscle modeling is accomplished by existing research results.To solve the problem of strong uncertainties of pneumatic artificial muscle,firstly,a finite-time uniformly ultimately bounded trajectory tracking control algorithm with the disturbance observer has been proposed.The disturbance observer,as a feedforward control,can overcome the uncertainties and the external disturbances of the pneumatic artificial muscle in the proposed strategy.Secondly,this paper proposed a trajectory tracking control algorithm with the finite-time disturbance observer.When the system states reach the sliding mode surface,the convergence of the finite-time disturbance observer is guaranteed,and the global convergence time is estimated.Lastly,we proposed a high-gain finite-time control algorithm,which can improve the convergence performance of the system by appropriately adjusting the high-gain parameters.This paper finally achieves these algorithms in Matlab with different models.The results indicates that the proposed algorithms perform successfully in disturbance-rejection performance,tracking preciseness and robustness,which can make a theoretical contribution to applications of the pneumatic artificial muscle.