The use of compliant joints and elastic energy storage in bio-inspired legged robots

From an engineering point of view, bio-inspiration can suggest mechanisms, design and functions successfully improving the state of the art in robotics. Engineers can study scaling effects in animal locomotion in order to determine the optimal gait for a given-size robot. In this paper the design of a miniature jumping robot is presented. Inspired by small jumping animals, the robot performs catapult jumps, using an elastic energy storage and a release mechanism. Compliant forelegs are completely passive, and cushion the landing re-using part of the impact energy. The influence of compliance and elastic energy storage on performances is discussed. Spring stiffness and elongation are dimensioned according to design limitations and energy constraints, avoiding early loss of ground contact, i.e. take-off before complete leg extension.