Motion control for a multi-DOF pneumatic manipulator via angle deflection gravity compensation

In this paper, a finite time control strategy is investigated to realize motion control for a multi-DOF pneumatic manipulator (MDPM) with vertical downward equilibrium state. Angle deflection is existed for the MDPM at work when gravity compensation has to take into account. To estimate the disturbances on gravity from angle deflection, a nonlinear extended state observer (ESO) is designed for the MDPM. Backstepping super-twisting terminal integral sliding mode control (SMC) is proposed to improve control accuracy and convergence speed. Finite time convergence is shown for the nonlinear ESO and the backstepping super-twisting terminal integral SMC under angle deflection gravity compensation. Experiment results are given to show effectiveness of the finite time control strategy for the MDPM.