Approximate Simulation for Template-Based Whole-Body Control

TL;DR

This paper introduces a novel template-based whole-body control method for legged robots, leveraging approximate simulation and Hamiltonian structure to enhance robustness and enable high center of mass walking.

Contribution

It presents a formal framework for template-based control using approximate simulation, exploiting Hamiltonian dynamics for improved robustness in high-dimensional systems.

Findings

Controller is passive and more robust to disturbances.

Supports high center of mass walking.

Validated on a 30-DOF humanoid model in simulations.

Abstract

Reduced-order template models are widely used to control high degree-of-freedom legged robots, but existing methods for template-based whole-body control rely heavily on heuristics and often suffer from robustness issues. In this letter, we propose a template-based whole-body control method grounded in the formal framework of approximate simulation. Our central contribution is to demonstrate how the Hamiltonian structure of rigid-body dynamics can be exploited to establish approximate simulation for a high-dimensional nonlinear system. The resulting controller is passive, more robust to push disturbances, uneven terrain, and modeling errors than standard QP-based methods, and naturally enables high center of mass walking. Our theoretical results are supported by simulation experiments with a 30 degree-of-freedom Valkyrie humanoid model.