Impact effects of biped contact with the environment

A biped system is subjected to an instant velocity change at the moment of impact with the environment. This instant velocity change is derived as a function of the biped state and the contact speed. The effects of the impact on the state, as well as on the constraints, are studied in biped landing on heels and toes simultaneously or on toes first. The control strategy that is called for in this case is zero final velocities and a somewhat arbitrary final position. Rate feedback and nonlinear position feedback are used for stability. The action of plantar fascia during toe landing is represented by a spring and dashpot pair. The arch of the foot is prevented by this action from collapsing. Digital computer simulations of toe landing are presented.