Abstract
In this paper, an impedance control system which uses together the inner torque control system with the disturbance observer is proposed for the pneumatic robot manipulator. It is assumed that the generated torque by a pneumatic actuator can be estimated from the pressure signals and the discharge volume. And we define that the disturbance torque includes the friction torque, load change and modeling error. At first in order to improve the control characteristics of pneumatic actuator driven by meter out method, we construct the inner torque control system by feeding back the generated torque. Secondly, to reduce the influence of the defined disturbance torque, we compose the impedance control systems with the disturbance observer which can estimate the defined disturbance torque based on the generated torque, the angular velocity and the reaction torque. In order to realize the robust impedance to the defined disturbance torque, we construct the torque based impedance control system which uses together the inner torque control system with the disturbance observer. The real command to the torque control system is generated from the impedance model and the positioning error. From some experiments, it is verified that the proposed impedance control system is effective to adjust the impedance of pneumatic robot manipulator.
