Coupling of Body Mechanics and Control for Robust and Efficient Quadrupedal Gait Generation

Legged locomotion is realized by the inextricably linked interplay of mechanics and control. While conventional engineering frameworks tended to focus merely on the control aspect, today robotics take the view that exploitation of morphology can very much embody the desired locomotor behavior within itself and thus facilitate control. In this regard, this work is centered around the design of a quadruped robot to investigate the question of to what extent morphological computation can help achieve efficient legged locomotion. For that, the architecture of the robot legs is developed with only one actuated unidirectional degree of freedom which embeds some control functionalities while being inherently energy efficient. With resourcing the control to the body, a simple speed regulator is shown to be sufficient for stable and robust locomotion. Thanks to the morphology, it is shown that by optimizing just a few design parameters, various gait patterns (i.e., walking, trotting, and bounding) emerge with a low transportation cost (as low as 0.54), comparable to animals. Moreover, gait transition in the face of speed change is another outcome observed in this design. The results support the fact that the distribution and transference of computations to the body can significantly simplify the control task and yield efficient, robust, and fast locomotion. It also suggests that this approach has the potential to be utilized for the realization of highly energy efficient legged robots.