Kinematic Modeling of Handed Shearing Auxetics via Piecewise Constant Curvature

TL;DR

This paper develops a novel kinematic model for Handed Shearing Auxetics (HSA) continuum robots using Piecewise Constant Curvature, enabling accurate prediction of their position and orientation for practical applications.

Contribution

It introduces a modified PCC model with a coupling matrix to accurately model HSA structures, filling a gap in existing continuum robot modeling.

Findings

Achieves mean positional error of 5.5mm (4.5%)

Achieves mean angular error of -2.8°

Model effectively predicts bending, extension, and compression behaviors

Abstract

Handed Shearing Auxetics (HSA) are a promising technique for making motor-driven, soft, continuum robots. Many potential applications from inspection tasks to solar tracking require accurate kinematic models to predict the position and orientation of these structures. Currently there are no models for HSA based continuum platforms. To address this gap we propose to adapt Piecewise Constant Curvature (PCC) Models using a length change coupling matrix. This models the interaction of HSA structures in a 2x2 array. The coupling matrix maps the change in motor angles to length changes and defines the configuration space in our modified PCC Model. We evaluate our model on a composite movement encompassing bending, extension and compression behavior. Our model achieves a positional accuracy with mean error of 5.5mm or 4.5% body length and standard deviation of 1.72mm. Further, we achieve an angular accuracy with mean error of -2.8$^\circ$ and standard deviation of 1.9$^\circ$.