A Simulation-Driven Graph Grammar Method for the Automated Synthesis of Passive Dynamic Brachiating Robots

Abstract

Topologic configurations of passive dynamic locomotion robots are usually designed manually by human designers and often bio-inspired. However, it is possible that, among the large number of possible configurations, some valid solutions to the problem exist that are potentially superior to existing solutions and, at the same time, different from bio-inspired or otherwise intuition-inspired configurations, and thus not likely discovered without an automated design method. This paper addresses the problem of the automated design of passive dynamic systems in general by introducing a graph grammar based method that integrates dynamic simulation to evaluate and evolve configurations. In particular, the method is shown to find different, new solutions to the problem of the design of two-dimensional passive dynamic continuous contact brachiating robots. Brachiating is the swinging locomotion of primates moving from one tree branch to the next. The presented graph grammar rules preserve system properties among robot topologies, which makes it possible to maintain the necessary symmetry of the brachiating configurations. A separation of parametric optimization and topologic synthesis actions is proposed for the synthesis of passive dynamic systems. Compared to research on automated synthesis of robot topologies that use dynamic simulation to evaluate actuated and controlled robotic systems, this paper contributes a method to automatically generate alternative topologies for passive dynamic systems, which do not draw energy from a power source.