RHex is essentially an autonomous hexapod robot with flexible legs, and only one actuator per leg. It’s actually the first ever documented autonomous legged machine to show general mobility (speeds at body-lengths per second) over general terrain (variations in level at body-height scale). Continue reading for more.
RHex is presently capable of speeds exceeding five body lengths per second (2.7 m/s), negotiates a wide variety of rugged terrains over thousands of bodylengths (3700 m distance on one set of batteries), manages slopes exceeding 45 degrees, swims, and climbs stairs.
4. The Bug
RHex arises from a multidisciplinary and multi-university DARPA funded effort in Computational Neuromechanics that applies mathematical techniques from dynamical systems theory to problems of animal locomotion, and, in turn, seeks inspiration from biology in advancing the state of the art of robotic systems.
The RHex project received $5 million over 5 years from the DARPA CBS/CBBS program in 1998, and an approximate additional $3 million from other grants, such as National Science Foundation grants. The following Universities participated on the initial RHex project.
Throughout its development, RHex acquired a large number of capabilities in its behavioral repertoire. In fact, it is the only robot that is capable of performing such a wide variety of behaviors as a single, autonomous robot. This performance is due to the significant amount of inspiration from the study of biological systems, leading to a number of principles underlying RHex’s design.
At the end of the project’s five years, RHex was capable of performing the following, mostly open-loop behaviors: Running on reasonably flat, natural terrain at speeds up to 6 body lengths per second (just over 2.7 m/s); Climbing a wide range of stairs; Climbing slopes up to 45 degrees; Travers obstacles as high as 20 cm (about twice RHex’s leg clearance).