Skin Normal Force Calibration Using Vacuum Bags

TL;DR

This paper introduces a novel calibration method for iCub's skin using vacuum bags to accurately measure normal forces by correlating pressure and sensor capacitance, validated through experiments on the robot's forearm.

Contribution

The paper proposes a new vacuum bag-based calibration technique for robot skin sensors, enabling precise force measurement calibration.

Findings

Calibration achieves acceptable average force prediction errors.

Method effectively correlates pressure with sensor capacitance.

Experimental validation on iCub's forearm demonstrates viability.

Abstract

The paper presents a proof of concept to calibrate iCub's skin using vacuum bags. The method's main idea consists in inserting the skin in a vacuum bag, and then decreasing the pressure in the bag to create a uniform pressure distribution on the skin surface. Acquisition and data processing of the bag pressure and sensors' measured capacitance allow us to characterize the relationship between the pressure and the measured capacitance of each sensor. After calibration, integration of the pressure distribution over the skin geometry provides us with the net normal force applied to the skin. Experiments are conducted using the forearm skin of the iCub humanoid robot, and validation results indicate acceptable average errors in force prediction.