Fast Whole-Body Motion Control of Humanoid Robots with Inertia Constraints

TL;DR

This paper presents an analytical method for humanoid robot motion control that efficiently approximates inertia properties, enabling rapid computation suitable for real-time applications and complex tasks.

Contribution

The authors introduce a novel five-mass model for humanoid inertia approximation, providing an analytical solution for whole-body motion generation with minimal computation.

Findings

Achieves computation times of tens of microseconds.

Successfully performs dynamic kicking motions.

Suitable for resource-limited real-time control.

Abstract

We introduce a new, analytical method for generating whole-body motions for humanoid robots, which approximate the desired Composite Rigid Body (CRB) inertia. Our approach uses a reduced five mass model, where four of the masses are attributed to the limbs and one is used for the trunk. This compact formulation allows for finding an analytical solution that combines the kinematics with mass distribution and inertial properties of a humanoid robot. The positioning of the masses in Cartesian space is then directly used to obtain joint angles with relations based on simple geometry. Motions are achieved through the time evolution of poses generated through the desired foot positioning and CRB inertia properties. As a result, we achieve short computation times in the order of tens of microseconds. This makes the method suited for applications with limited computation resources, or leaving them to be spent on higher-layer tasks such as model predictive control. The approach is evaluated by performing a dynamic kicking motion with an igus Humanoid Open Platform robot.