Biped control to follow arbitrary referential longitudinal velocity based on dynamics morphing

Abstract

A novel biped control is proposed. Since it doesn't require referential motion trajectories defined by time, it can achieve longitudinal walking which is flexible enough to follow an arbitrary referential velocity given at random timing and to cope with unexpected external forces. The controller is developed based on the dynamics morphing, which is a framework to enable seamless transitions between various motions by continuously morphing the dynamical structure of the feedback system. Thus, it is compatible with the standing, the stepping-out for emergency, and so forth. Three key techniques are (i) morphing from the standing stabilizer with a stable equilibrium point to the velocity-follower which lacks any equilibrium points, (ii) a foot control maneuver which is automatically activated together with the morphing into the velocity following control, and (iii) automatic update of the referential position of COM for safety when going back to the standing stabilization. Although it is based on the same principle with the simulated regulator proposed by the author, the proposed controller is advantageous to it as it doesn't require an additional automaton to update the referential position of COM. The idea was examined through interactive computer simulations.