Torso and swing-leg control for a planar biped walker with hip series elastic actuators

Passive walkers which can walk stably down a shallow slope without actuators show that exploiting the passive dynamics leads to efficient walking. In this paper, a simple planar biped robot with a torso are considered. We investigated level-ground walking based on the passive dynamics by using a torso and swing-leg control with hip series elastic actuators. The series elastic actuator comprised springs in series with a motor. Numerical simulations showed that the walking speed increases with the desired torso angle and the walking stability are mainly determined by the motor control gain. The simulations demonstrated that the biped robot with the series elastic actuator can walk stably at various speeds via torso and swing-leg control.