Developing a control framework for self-adjusting prosthetic sockets incorporating tissue injury risk estimation and generalized predictive control
Developing a control framework for self-adjusting prosthetic sockets incorporating tissue injury risk estimation and generalized predictive control
To perform activities of daily living (ADL), people with lower limb amputation depend on the prosthetic socket for stability and proprioceptive feedback. Poorly fitting sockets can cause discomfort, pain, limb tissue injuries, limited device usage, and potential rejection. Semi-passively controlled adjustable socket technologies exist, but these depend upon the user’s perception to determine safe interfacial pressure levels. This paper presents a framework for automatic control of an adjustable transtibial prosthetic socket that enables active adaptation of residuum-socket interfacial loading through localized actuators, based on soft tissue injury risk estimation. Using finite element analysis, local interfacial pressure vs. compressive tissue strain relationships were estimated for three discrete anatomical actuator locations, for tissue injury risk assessment within a control structure. Generalized Predictive Control of multiple actuators was implemented to maintain interfacial pressure within estimated safe and functional limits. Controller simulation predicted satisfactory dynamic performance in several scenarios. Actuation rates of 0.06–1.51 kPa/s with 0.67% maximum overshoot, and 0.75–1.58 kPa/s were estimated for continuous walking, and for a demonstrative loading sequence of ADL, respectively. The developed platform could be useful for extending recent efforts in adjustable lower limb prosthetic socket design, particularly for individuals with residuum sensory impairment.
Adjustable prosthetic socket, Finite element analysis, Generalized predictive control, Interface pressure control, Transtibial
Mbithi, Florence M.
68aa5a1e-9252-4264-8057-9bc3a7174939
Chipperfield, Andrew
524269cd-5f30-4356-92d4-891c14c09340
Steer, Joshua
19fab79c-1991-4762-85da-abda7ce82ab1
Dickinson, Alexander
10151972-c1b5-4f7d-bc12-6482b5870cad
2 December 2021
Mbithi, Florence M.
68aa5a1e-9252-4264-8057-9bc3a7174939
Chipperfield, Andrew
524269cd-5f30-4356-92d4-891c14c09340
Steer, Joshua
19fab79c-1991-4762-85da-abda7ce82ab1
Dickinson, Alexander
10151972-c1b5-4f7d-bc12-6482b5870cad
Mbithi, Florence M., Chipperfield, Andrew, Steer, Joshua and Dickinson, Alexander
(2021)
Developing a control framework for self-adjusting prosthetic sockets incorporating tissue injury risk estimation and generalized predictive control.
Biomedical Engineering Letters.
(doi:10.31224/osf.io/cd6pg).
Abstract
To perform activities of daily living (ADL), people with lower limb amputation depend on the prosthetic socket for stability and proprioceptive feedback. Poorly fitting sockets can cause discomfort, pain, limb tissue injuries, limited device usage, and potential rejection. Semi-passively controlled adjustable socket technologies exist, but these depend upon the user’s perception to determine safe interfacial pressure levels. This paper presents a framework for automatic control of an adjustable transtibial prosthetic socket that enables active adaptation of residuum-socket interfacial loading through localized actuators, based on soft tissue injury risk estimation. Using finite element analysis, local interfacial pressure vs. compressive tissue strain relationships were estimated for three discrete anatomical actuator locations, for tissue injury risk assessment within a control structure. Generalized Predictive Control of multiple actuators was implemented to maintain interfacial pressure within estimated safe and functional limits. Controller simulation predicted satisfactory dynamic performance in several scenarios. Actuation rates of 0.06–1.51 kPa/s with 0.67% maximum overshoot, and 0.75–1.58 kPa/s were estimated for continuous walking, and for a demonstrative loading sequence of ADL, respectively. The developed platform could be useful for extending recent efforts in adjustable lower limb prosthetic socket design, particularly for individuals with residuum sensory impairment.
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Accepted/In Press date: 8 November 2021
Published date: 2 December 2021
Additional Information:
Funding Information:
This work was supported by: FMM: the Commonwealth Scholarship Commission UK under Ref. No. CA-16–28. JWS: the University of Southampton’s EPSRC Doctoral Training Program under Ref. No. EP/M508147/1. ASD: the Royal Academy of Engineering UK under Ref. No. RF/130.
Publisher Copyright:
© 2021, Korean Society of Medical and Biological Engineering.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
Keywords:
Adjustable prosthetic socket, Finite element analysis, Generalized predictive control, Interface pressure control, Transtibial
Identifiers
Local EPrints ID: 452264
URI: http://eprints.soton.ac.uk/id/eprint/452264
ISSN: 2093-9868
PURE UUID: 53f390eb-1d84-4bde-997a-0f67ade96065
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Date deposited: 02 Dec 2021 17:34
Last modified: 24 Apr 2024 01:41
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Contributors
Author:
Florence M. Mbithi
Author:
Joshua Steer
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