Robot joint characterisation and control using a magneto-optical rotary encoder

TL;DR

This paper introduces a compact magneto-optical rotary encoder for robotic joints that offers high-resolution, reliable, and cost-effective rotation measurement suitable for various robotic applications.

Contribution

The paper presents a novel magneto-optical encoder design capable of continuous 360-degree rotation tracking with high resolution and speed, providing a robust alternative to traditional encoders.

Findings

Tracks continuous 360° rotation at 135-370°/s

Achieves angular resolution of 0.3°

Offers a low-cost, reliable solution

Abstract

A robust and compact magneto-optical rotary encoder for the characterisation of robotic rotary joints is demonstrated. The system employs magnetic field-induced optical attenuation in a double-pass configuration using rotating nonuniform magnets around an optical circulator operating in reflection. The encoder tracks continuous 360{\deg} rotation with rotation sweep rates from {\nu} = 135 {\deg}/s to {\nu} = 370 {\deg}/s, and an angular resolution of {\Delta}{\theta} = 0.3{\deg}. This offers a low-cost and reliable alternative to conventional robot rotation encoders while maintaining competitive performance.