Position Control of Soft-Robots with Rotary-Type Pneumatic Actuators

The objective of this work is the development and evaluation of a non-linear control concept for pneumatic soft-robots based on direct acting actuators of rotary-type (REC-actuators). Providing lightweight and inherent compliance, pneumatic soft-actuators are very suitable to construct service and rehabilitation robots, intended to work in direct contact with humans. However, an accurate and robust control of such robots is a challenging task, due to their high non-linear dynamics, especially for robots with a number of rotary joints. In this paper the usability of a decentralized joint position control scheme is experimentally investigated for soft-robots with two different kinematics, containing 4 and 6 REC-actuators respectively. It is shown, that complemented with active gravity compensation, based on the quasi-static robot model as feed-forward signal, the decentralized control scheme can be successfully applied to achieve robust joint space position control of soft-robots.