Multi-Contact Motion Retargeting using Whole-body Optimization of Full Kinematics and Sequential Force Equilibrium

TL;DR

This paper introduces a real-time multi-contact motion retargeting framework for high-DoF robots, enabling stable teleoperation of complex loco-manipulation tasks through whole-body optimization and sequential quadratic programming.

Contribution

It presents a novel optimization-based approach for multi-contact motion retargeting that is robust, stable, and suitable for real-time teleoperation of legged robots.

Findings

Effective in simulation for various legged robots

Enables real-time, stable multi-contact motions

Reduces operator cognitive load

Abstract

This paper presents a multi-contact motion adaptation framework that enables teleoperation of high degree-of-freedom (DoF) robots, such as quadrupeds and humanoids, for loco-manipulation tasks in multi-contact settings. Our proposed algorithms optimize whole-body configurations and formulate the retargeting of multi-contact motions as sequential quadratic programming, which is robust and stable near the edges of feasibility constraints. Our framework allows real-time operation of the robot and reduces cognitive load for the operator because infeasible commands are automatically adapted into physically stable and viable motions on the robot. The results in simulations with full dynamics demonstrated the effectiveness of teleoperating different legged robots interactively and generating rich multi-contact movements. We evaluated the computational efficiency of the proposed algorithms, and further validated and analyzed multi-contact loco-manipulation tasks on humanoid and quadruped robots by reaching, active pushing and various traversal on uneven terrains.