Stabilization of Gaits for the SemiQuad Robot

Abstract

It was desired to make an orbitally stabilizing controller for a series of designed gaits for the SemiQuad robot. The designed gaits had virtual constraints of the second and third order. It was found that the gaits that had virtual constraints of third order broke a design restriction, which made the stance foot lift off the ground. The second order gaits did not break this restriction. A constant gain feedback controller was found to not be able to orbitally stabilize the gait. A linearization was made using the method of transverse linearization for one of the gaits with second degree constraints, and a controller was designed for this linearization. This controller stabilized the linearized system. The controller was not found to be able to stabilize the original nonlinear system. It was concluded that the gaits were of a too complicated nature to stabilize with this controller. A new gait was therefore created, which was of a simpler nature with a prolonged double support phase. This new gait was stabilized with a constant gain controller.