A bioinspired concept for high efficiency locomotion in micro robots: the jumping Robot Grillo

Abstract

This paper presents a bioinspired concept of locomotion for small autonomous robots. Scale effects in locomotion highly influence gait efficiency and in lightweight micro-robots jumping can be more energetically efficient than just walking or climbing. In addition, a jump can make the robot overcome obstacles and uneven terrains. Inspired by nature, the actuation of the proposed robot is entrusted to loaded springs. During the flight phase, energy from an electric micro-motor is collected in springs, while it is released by a click mechanism during take-off. In this way instant power delivered by rear legs (about 5 W) is much higher than the one provided by the motor (0.3 W). Passive compliant legs and low-power actuation result in light, efficient micro-robot, designed to have long autonomy for environment exploration and monitoring. In order to verify these assumptions, a quadruped prototype was developed, with two active rear limbs and passive elastic forelegs. Robot Grillo is 50 mm long and weighs about 10 grams. In conservative simulations the microrobot reaches a forward speed of 1.5 m/s, which corresponds to about 30 body length s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup>