Lift-off dynamics in a simple jumping robot

Abstract

We study vertical jumping in a simple robot comprising an actuated mass-spring arrangement. The actuator frequency and phase are systematically varied to find optimal performance. Optimal jumps occur above and below (but not at) the robot's resonant frequency \(f_0\). Two distinct jumping modes emerge: a simple jump which is optimal above \(f_0\) is achievable with a squat maneuver, and a peculiar stutter jump which is optimal below \(f_0\) is generated with a counter-movement. A simple dynamical model reveals how optimal lift-off results from non-resonant transient dynamics.