Position and Compliance Control of a Manipulator with Pneumatic Muscles for Enhanced Safety

The safety of humans who work with robots is an important issue. Many studies have addressed related methods, but fundamental limits to meet safety requirements have been encountered owing to the absence of compliance in robot actuators. Pneumatic muscle is considered to be a basic actuator and offers the advantage of intrinsic elasticity to achieve joint compliance. In this study, joint compliance actuated by pneumatic muscle is actively utilized to enhance human safety during collisions. To this end, the authors present a novel approach to control compliance and associated positions independently with no cross-performance effects using pneumatic muscles. The proposed method is verified by simulation and experiments using a physical robot.