Compliant Biped Walking on Uneven Terrain with Point Feet

Abstract

In this paper, we aim to realize compliant biped walking on uneven terrain with point feet. A control system is designed for a 5-link planar biped walker. According to the role that each leg plays, the control system is decomposed into two parts: the swing leg control and the support leg control. The trajectory of the swing foot is generated in realtime to regulate the walking speed. By considering the reaction torque of the swing leg's hip joint as disturbance, a sliding model controller is implemented at the support leg's hip joint to control the torso's posture angle. In order to make sure the landing foot does not rebound after impact, the vertical contact force control is set as the internal loop of the hip's height control. In simulation, the control system is tested on a virtual 5-link planar biped walker in Matlab. Finally, stable biped walking is realized on uneven terrain with roughness up to 2cm.

A Stabilization Method Based on an Adaptive Feedforward Controller for the Underactuated Bipedal Walking with Variable Step-Length on Compliant Discontinuous Ground

“…As a result, the rigid ground assumption is no longer valid, and the robot-ground impact model is no longer independent of the ground compliance as well [14][15][16][17][18]. In documents, the effect of ground compliance on the bipedal locomotion and the control strategies to cope with it have been studied [19][20][21][22][23][24][25][26].…”

Feedforward control for underactuated bipedal walking on compliant continuous steps with varying height

“…A linear robust controller is constructed by using binary search and iterative optimization to improve the adaptability of the robot to uneven ground. Underactuated biped walking control is decomposed into two parts: the swing leg control and the support leg control, and stable biped walking is realized on uneven terrain with roughness up to 2cm (Hou et al, 2016). Nguyen utilizes a two-step periodic gait optimization technique to build a library of gaits, and the method is successfully validated on an underactuated bipedal robot ATRIAS (Nguyen et al, 2018).…”