Active disturbance rejection control of a strongly nonlinear and disturbed piezoelectric actuator devoted to robotic hand

The target of this paper is to model and to design a controller for a piezoelectric actuator that is devoted to robotic hand. The actuator is characterized by the following properties simultaneously: strong asymmetrical hysteresis nonlinearity, creep nonlinearity, and oscillations in its dynamics. Moreover, the actuator is also exhibited to external disturbance which is the manipulation force. To account for these specificities, we propose to use the generalized Bouc-Wen model for the hysteresis, along with a lumped disturbance term that encompasses the creep and the external force. We also propose to use a high order model for the dynamics. Then, an active disturbance rejection in combination with an extended state observer is suggested and designed as control law. Experiments are carried out and demonstrate the efficiency of the proposed approach.