Control of the Lateral Motion in Biped Walking Based on the Assumption of Point-contact

This paper proposes the novel control method named Passive Dynamic Autonomous Control (PDAC) PDAC is based on the following concept which Grizzle et al. employed previously : 1) point-contact 2) Virtual constraint. Point-contact means that the contact state between a robot and the ground is point. This makes it possible to generate the robot motion based on the robot inherent dynamics although it becomes difficult to control. Virtual constraint means that all robot joints are connected and interlocked. We present the new approach by means of these concepts to express the whole robot dynamics an an 1-dimensional autonomous system. Due to autonomy, this approach has two following notable points : 1) period from foot-contact to next foot-contact can be obtained 2) there is a conservative quantity to make it possible to stabilize the motion. As the first step of realization of 3 D dynamic walking, this paper applies PDAC to the lateral motion and builds the controller. In addition, the stabilization and motion period control are reported. The validity of these control is confirmed by experiment and desired lateral motion is realized.