# Thermal Recovery of Multi-Limbed Robots with Electric Actuators

## TL;DR

This paper presents a data-driven thermal inverse-kinematics method for humanoid robots to find configurations that minimize actuator temperatures, validated on NASA Valkyrie hardware.

## Contribution

It introduces a novel effort-based thermal model and a contact-constrained thermal IK approach for thermal recovery in multi-limbed robots.

## Key findings

- Successfully predicts future thermal states of actuators.
- Optimizes robot configurations to reduce thermal risk.
- Validated on NASA Valkyrie robot hardware.

## Abstract

The problem of finding thermally minimizing configurations of a humanoid robot to recover its actuators from unsafe thermal states is addressed. A first-order, data-driven, effort-based, thermal model of the robot's actuators is devised, which is used to predict future thermal states. Given this predictive capability, a map between configurations and future temperatures is formulated to find what configurations, subject to valid contact constraints, can be taken now to minimize future thermal states. Effectively, this approach is a realization of a contact-constrained thermal inverse-kinematics (IK) process. Experimental validation of the proposed approach is performed on the NASA Valkyrie robot hardware.