Enabling Tactile Feedback for Robotic Strawberry Handling using AST Skin

TL;DR

This paper demonstrates the use of Acoustic Soft Tactile (AST) skin on a robotic finger to enable real-time tactile feedback for precise strawberry handling, highlighting its calibration, design, and successful force-controlled gripping performance.

Contribution

It introduces a novel application of AST skin on a robotic end effector for agricultural tasks, showcasing calibration, design, and real-time tactile feedback capabilities.

Findings

Successful gripping of strawberries with 2 N force

Maximum MAE of 0.31 N in force measurement

AST skin enables real-time tactile feedback for manipulation

Abstract

Acoustic Soft Tactile (AST) skin is a novel sensing technology which derives tactile information from the modulation of acoustic waves travelling through the skin's embedded acoustic channels. A generalisable data-driven calibration model maps the acoustic modulations to the corresponding tactile information in the form of contact forces with their contact locations and contact geometries. AST skin technology has been highlighted for its easy customisation. As a case study, this paper discusses the possibility of using AST skin on a custom-built robotic end effector finger for strawberry handling. The paper delves into the design, prototyping, and calibration method to sensorise the end effector finger with AST skin. A real-time force-controlled gripping experiment is conducted with the sensorised finger to handle strawberries by their peduncle. The finger could successfully grip the strawberry peduncle by maintaining a preset force of 2 N with a maximum Mean Absolute Error (MAE) of 0.31 N over multiple peduncle diameters and strawberry weight classes. Moreover, this study sets confidence in the usability of AST skin in generating real-time tactile feedback for robot manipulation tasks.