The Decoupling Control for Pma-driven Serial Mechanism

The serial mechanism is driven by pneumatic muscle actuators (PMA) and used the tendon transmission structure. Between the various joints, the torque coupling and the location coupling seriously affect the control performance. By analyzing the location equation of tendons, a matrix which can describe the coupling is obtained. Combined with the model of PMA, the dynamic equation of the coupled system is derived. For features of the tendon drive coupling and PMA, the computed torque algorithm is improved. In order to overcome the hysteresis of PMA, the control signal is compensated ahead. Finally the decoupling control algorithm which adapted to the PMA drive and the tendon drive is proposed. Experiment proved that, compared to the PID control, improved computed-torque control can decreases the coupling, accelerates the response speed and decreases the steady-state error.