Acoustic Feedback for Closed-Loop Force Control in Robotic Grinding

TL;DR

This paper presents a low-cost acoustic feedback system for robotic grinding that estimates force from audio signals, enabling effective closed-loop control and outperforming traditional force sensors in consistency.

Contribution

Introduction of AFRG, a cost-effective acoustic feedback system that estimates grinding force from audio, reducing reliance on expensive force sensors.

Findings

AFRG achieves a 4-fold improvement in consistency across grinding conditions.

AFRG uses a microphone approximately 200 times cheaper than traditional force sensors.

The system enables real-time force estimation and closed-loop control in robotic grinding.

Abstract

Acoustic feedback is a critical indicator for assessing the contact condition between the tool and the workpiece when humans perform grinding tasks with rotary tools. In contrast, robotic grinding systems typically rely on force sensing, with acoustic information largely ignored. This reliance on force sensors is costly and difficult to adapt to different grinding tools, whereas audio sensors (microphones) are low-cost and can be mounted on any medium that conducts grinding sound. This paper introduces a low-cost Acoustic Feedback Robotic Grinding System (AFRG) that captures audio signals with a contact microphone, estimates grinding force from the audio in real time, and enables closed-loop force control of the grinding process. Compared with conventional force-sensing approaches, AFRG achieves a 4-fold improvement in consistency across different grinding disc conditions. AFRG relies solely on a low-cost microphone, which is approximately 200-fold cheaper than conventional force sensors, as the sensing modality, providing an easily deployable, cost-effective robotic grinding solution.