A robust adaptive tracking control method for a rehabilitative walker using random parameters

ABSTRACT

The present paper investigates stochastic modelling and a new nonlinear reliable tracking control method for a rehabilitative training walker. The stochastic model is constructed by considering random parameters. A new nonlinear tracking method against actuator fault is proposed based on redundant degree of freedom and a state feedback controller is designed by exploiting an adaptive control technique. It is proved that the mean square of the trajectory tracking error can be made arbitrarily small by choosing appropriate design parameters. As an application, simulation results confirm the effectiveness of the proposed method and verify that the walker with random parameters can provide safe sequential motion when one wheel actuator is at fault.

KEYWORDS:

• Random parameters
• reliable tracking control
• rehabilitative training walker
• adaptive control

Acknowledgements

The authors would like to thank the Associate Editor and the reviewers for their constructive comments and suggestions, who have helped to improve the quality and clarity of the present paper.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The present study was supported by the Japan Society for the Program of Science KAKENHI [grant number 24300203], [grant number 23240088], [grant number 22300197]; the Canon Foundation, the Program for Liaoning Excellent Talents in University of China [grant number LJQ2014013]; the Liaoning Natural Science Foundation of China [grant number 2015020066].