Title: Design and simulation of fuzzy-based nonlinear-PID and sliding mode controllers for ankle rehabilitation soft wearable robot

Authors: Beykaso Abayneh

Addresses: Department of Electromechanical Engineering, Addis Ababa Science and Technology University, Addis Ababa, Ethiopia; Metals Industry Development Institute, PO 1180, Addis Ababa, Ethiopia

Abstract: Soft robotics has become an active research area due to its compliance with the natural anatomy, volume to weight ratio, and overall compatibility. However, the difficulties in controlling soft robots have remained a challenge for employing soft wearable robots for clinical applications. In this paper, a fuzzy-based nonlinear PID controller and higher-order sliding mode controllers which can maintain robustness in the presence of a disturbance signal have been designed and analysed. A simple innovative way to include pain signals in control design has been developed; the patient is actively involved by feeding the pain signal to the controller. The pain signal will be characterised into predefined categories from the physiotherapist's knowledge; a fuzzy controller is developed to generate reference force output for the controller from pain feedback and rate of change of muscle elongation. The developed models were analysed and simulated in MATLAB Simulink and Simscape's physical modelling environment.

Keywords: ankle rehabilitation; soft wearable robot; fuzzy logic control; nonlinear PID; N-PID; sliding mode control; SMC.

DOI: 10.1504/IJBBR.2022.128671

International Journal of Biomechatronics and Biomedical Robotics, 2022 Vol.4 No.1, pp.1 - 12

Accepted: 16 Feb 2022
Published online: 01 Feb 2023 *

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