Lower body exoskeleton for walking gait assistance and performance augmentation using compliance controlled actuators

Costa, NRS 2008, Lower body exoskeleton for walking gait assistance and performance augmentation using compliance controlled actuators , PhD thesis, University of Salford.

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Successful motor rehabilitation after stroke or traumatic brain/spinal cord injures requires a highly intensive and task-specific therapy-based approach. Currently many patients with these types of pathologies are confined to wheelchairs, which results in a sedentary lifestyle causing other critical secondary health conditions and increased dependence on a carer. Increasing evidence has shown that locomotor training can reduce the incidence of these secondary pathologies, but the physical effort required from patients and the cost, time and intensive load on the physiotherapists involved in these regular locomotor walking exercises is such that there is poor compliance. A new range of intelligent assistive machines may offer an alternative and more efficient solution to promote motor rehabilitation recovery and obtain a better understanding of human motor control required for these subjects. This thesis reports on the complete development from design, and construction to the testing and performance analyses of a new "human friendly" 10-degree of freedom lower body exoskeleton for walking gait assistance and also generic human force augmentation. The twin wearable legs are powered by 20 braided pneumatic Muscle Actuators (pMAs); a new, low mass, high power to weight and volume actuation system. In addition, the pMAs produce a muscle-like contact, taking advantage of their inherent nature which weakens linearly as it contracts and as such can be considered a soft and biomimetic actuation system. The combination of a highly compliant actuation system, with a lower level embedded control system which senses hip, knee, and ankle position, velocity, acceleration and force, produces powerful yet inherently safe operation for patients. This capacity to "replicate" the function of natural muscle and inherent safety is extremely important when working in close proximity to humans particularly those suffering a disability. These actuators are driven from a developed novel power energy source that has excellent autonomy potential. An integrated system comprising all the components in a pMA controller network architecture of interconnected microcontrollers (uCs) and a highly advanced wireless interface has been developed to control the actuators and provide sensing, communication and monitoring. Using this topology, it has been demonstrated how the structure, low level control system and actuators can be combined to generate a variety of walking gaits or strategies needed for a highly flexible/low weight clinically viable rehabilitation exoskeleton. Further more, the application of this technology in an advanced rehabilitation centre with active partial body weight support over a treadmill with automatic position and velocity control demonstrated that is has the potential to greatly improve the therapeutic approach and rehabilitative protocols for paraplegic patients and neurologic injured users. This novel powered locomotor trainer aims to promote motor recovery, reducing this effort to a tolerable level encouraging higher levels of exercise, improved secondary health care and to obtain a better understanding of human motor walking gait.

Item Type: Thesis (PhD)
Contributors: Nefti-Meziani, S (Supervisor)
Schools: Schools > School of Computing, Science and Engineering
Funders: Escola Superior de Tecnologia e Gestao of the Institute Politecnico de Leiria, Fundasao para a Ciencia e a Tecnologia (FCT)
Depositing User: Institutional Repository
Date Deposited: 17 Aug 2021 07:26
Last Modified: 04 Aug 2022 11:22
URI: https://usir.salford.ac.uk/id/eprint/61582

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