Design and control of a bio-inspired human-friendly robot

The increasing demand for physical interaction between humans and robots has led to an interest in robots that guarantee safe behavior when human contact occurs. However, attaining established levels of performance while ensuring safety creates formidable challenges in mechanical design, actuation, sensing and control. To promote safety without compromising performance, a human-friendly robotic arm has been developed using the concept of hybrid actuation. The new design employs high-power, low-impedance pneumatic artificial muscles augmented with small electrical actuators, distributed compact pressure regulators with proportional valves, and hollow plastic links. The experimental results show that significant performance improvement can be achieved with hybrid actuation over a system with pneumatic muscles alone. In this paper we evaluate the safety of the new robot arm through experiments and simulation, demonstrating that its inertia/power characteristics surpass those of previous human-friendly robots we have developed.