A Generalized Modeling Approach to Liquid-driven Ballooning Membranes

TL;DR

This paper introduces a novel ellipsoid-based modeling approach for liquid-driven ballooning membranes in soft robotics, enabling accurate shape and force estimation using only pressure and volume data, validated through experiments.

Contribution

The paper presents a new modeling method for ballooning membranes that simplifies shape estimation and control using intrinsic pressure feedback, improving accuracy over previous models.

Findings

RMSE for indentation depth is 0.80 mm, 23% of the range.

Force estimation RMSE is 0.15 N, 10% of the force range.

Model validated with experimental data showing high accuracy.

Abstract

Soft robotics is advancing the use of flexible materials for adaptable robotic systems. Membrane-actuated soft robots address the limitations of traditional soft robots by using pressurized, extensible membranes to achieve stable, large deformations, yet control and state estimation remain challenging due to their complex deformation dynamics. This paper presents a novel modeling approach for liquid-driven ballooning membranes, employing an ellipsoid approximation to model shape and stretch under planar deformation. Relying solely on intrinsic feedback from pressure data and controlled liquid volume, this approach enables accurate membrane state estimation. We demonstrate the effectiveness of the proposed model for ballooning membrane-based actuators by experimental validation, obtaining the indentation depth error of $RMSE_{h_2}=0.80\;$mm, which is $23\%$ of the indentation range and $6.67\%$ of the unindented actuator height range. For the force estimation, the error range is obtained to be $RMSE_{F}=0.15\;$N which is $10\%$ of the measured force range.