Abstract
This paper describes a design method of a position control system using a disturbance observer for a pneumatic robot manipulator. First, to control the dynamic characteristics of a pneumatic actuator, a pressure control system was developed. The two-degrees-of-freedom control system is used to standardize a pressure response of a pneumatic actuator to the desirable reference characteristic model. Second, to improve the control performance, the position control system using a disturbance observer is designed based on the reference characteristic model. The transfer function of the position control system corresponds with the reference characteristic model when the position control system is at its height against the nonlinear forces such as frictional forces and gravity. The position control system can be designed easily based on the reference characteristic model. Finally, the position control system of a pneumatic robot is applied to impedance control to implement flexible contact motions such as when a robot makes contact with a part of the human body. The validity of the proposed design method is confirmed by the experiments and evaluation of the stability using the root locus method.
