Hybrid Force-Motion Control for One-Legged Robot in Operational Space

Abstract

This paper presents a dynamic locomotion generation for a one-legged floating-base robot. Reference synthesis is performed by planning both swing motion of the foot and contact forces acting from the ground. A fifth-order polynomial is employed as the position reference to reduce the impact forces and ensure a steady transition between the swing and stance phases. Contact force references are designed utilizing the laws of linear and angular momentum conservation. A hybrid forcemotion control framework is created in operational space for tracking generated references. Gait phase transition is proposed to assist the transition between the force and motion controller. A full-dynamics simulation environment is utilized to test the proposed control framework. Results supported the competence of the proposed control framework for the floating-base onelegged robot.

Whole-Body Pace Gait Control Based on Centroidal Dynamics of a Quadruped Robot

“…The shared result belongs to the left front foot of the robot. Since our constraintbased contact model does not require ground penetration, it performed better than our previous spring-damper-based contact model [25]. Due to scaling in Figure 3, the force reference trajectory appears to be constant, however, it actually follows an elliptical orbit.…”

“…Therefore, the swing phase reference trajectory of the foot is constructed by a polynomial that have zero arriving velocity and acceleration to the floor. Additional information is supplied in [25].…”