Electrically-latched compliant jumping mechanism based on a dielectric elastomer actuator

Abstract

Jumping mechanisms are useful in robotics for locomotion in unstructured environments, or for self-righting abilities. However, most rigid robots rely on impact with the ground to jump, thereby requiring a relatively rigid, and flat environment. Moreover, they need to be able to absorb high impact forces during landing in order to maintain structural integrity. In this paper we investigate soft systems, capable of jumping repeatedly in unstructured environments with no need for precise landings. Our impulsive approach is based on a soft electro-mechanical transducer, a dielectric elastomer actuator (DEA). The design is inspired by click-beetles and simple bio-mechanical models, which convert the flexing around a hinge into jumping. Our actuator is power amplified by the addition of a stiffer strip, allowing for rapid shape transitions (22 ms) between flat and curved states. The transition is controlled by an electric latch: the DEA is discharged faster than the actuator can deform. The mechanical energy stored in the composite beam is released rapidly, leading to impulsive motions (jumps of a full body length: i.e. 5 cm). This demonstration of an electrically-latched power amplification mechanism shows that relatively simple electro-mechanical systems can exhibit impulsive behavior which may enable new types of locomotion in compliant machines.