Abstract
A pneumatic actuator makes it possible to construct light and small motion control system, because it has the characteristics of high power/weight ratio and so on. The flexibility due to air compressibility is fairly effective for contact tasks with soft and fragile objects, for example, as a human. On the contrary, the low stiffness due to air compressibility makes the control performance easily influenced by a friction force at sliding part.
In this study, a 3 D.O.F. flexible actuator without sliding part comprising elastic rubber balls is developed as an end effector of robot manipulator. The modelled static characteristics are compared with some experiments. It is shown that in the low pressure range, the characteristics of actuator can be approximated by the linear model derived based on the concept of spherical shell. The position control system is constructed according to the linear actuator model and the fundamental position control performances are investigated. In some experimental results obtained from PI controller, the satisfactory position control performances are obtained.
