Whole-Body Contact Sensing via Distributed Low-Cost Joint Torque Sensors for Legged Robots

Jared Grinberg, Yanran Ding

Keywords: Contact detection, joint torque sensing, legged robots, momentum observer, whole-body sensing, collision detection

TL;DR: We achieve sub-centimeter collision localization and <0.2N force estimation error on legged robots using distributed low-cost strain-gauge torque sensors with a hip-mounted FT sensor in a momentum-based observer, eliminating friction modeling.

Abstract: We present a method for detecting and localizing contact on legged robots using distributed low-cost strain-gauge joint torque sensors and a single hip-mounted force-torque (FT) sensor within a momentum-based observer framework. Our custom designed low-cost strain-gauge-based joint torque sensors provide direct measurements at the motor output shaft, bypassing drivetrain friction and eliminating the need for friction models and motor current estimation. Simulation and hardware experiments on a 2-DOF planar test leg demonstrate sub-centimeter contact localization accuracy and force errors below 0.2 N. Torque estimates from our sensors achieved an average 96.4% fidelity to ground truth measurements.

Submission Number: 8