Control of Manipulator Using Pneumatic Muscles for Enhanced Safety

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 (PM) is considered to be a basic actuator and offers the advantage of intrinsic elasticity to achieve joint compliance. In this paper, joint compliance actuated by PM 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 PMs. The proposed method is verified by experiments using a physical robot. In addition, methods to decrease damage from collisions between robots and humans due to operational faults are evaluated through experiments. The effectiveness of the proposed method is verified by measuring the impact impulse in collisions.