Two Degree of Freedom Adaptive Control for Hysteresis Compensation of Pneumatic Continuum Bending Actuator

TL;DR

This paper presents a novel two-degree-of-freedom adaptive control method for pneumatic continuum actuators, significantly improving bending tracking accuracy by effectively compensating for hysteresis nonlinearities.

Contribution

The paper introduces a new adaptive control strategy that integrates adaptability into both feedback and feedforward components for better hysteresis compensation in soft pneumatic actuators.

Findings

Enhanced trajectory tracking accuracy compared to existing methods

Effective hysteresis compensation in pneumatic bending actuators

Adaptive control improves robustness to nonlinear effects

Abstract

Soft robotics, with their inherent flexibility and infinite degrees of freedom (DoF), offer promising advancements in human-machine interfaces. Particularly, pneumatic artificial muscles (PAMs) and pneumatic bending actuators have been fundamental in driving this evolution, capitalizing on their mimetic nature to natural muscle movements. However, with the versatility of these actuators comes the intricate challenge of hysteresis - a nonlinear phenomenon that hampers precise positioning, especially pronounced in pneumatic actuators due to gas compressibility. In this study, we introduce a novel 2-DoF adaptive control for precise bending tracking using a pneumatic continuum actuator. Notably, our control method integrates adaptability into both the feedback and the feedforward element, enhancing trajectory tracking in the presence of profound nonlinear effects. Comparative analysis with existing approaches underscores the superior tracking accuracy of our proposed strategy. This work discusses a new way of simple yet effective control designs for soft actuators with hysteresis properties.