Multi-Point Contact Models for Dynamic Self-Righting of a Hexapod

Abstract

In this paper, we report on the design of a model-based controller that can achieve dynamical self-righting of a hexapod robot. Extending on our earlier work in this domain, we introduce a tractable multi-point contact model with Coulomb friction. We contrast the singularities inherent to the new model with other available methods and show that for our specific application, it yields dynamics which are well-defined. We then present a feedback controller that achieves “maximal” performance under morphological and actuation constraints, while ensuring the validity of the model by staying away from singularities. Finally, through systematic experiments, we demonstrate that our controller is capable of robust flipping behavior.

Keywords: legged robot, model based control, contact modeling, flipping, RHex

Portions of the material in this paper, in combination with material excerpted from [14] have been submitted for publication to the International Journal of Robotics Research.