ASSISTIVE DEVICE FOR LOWER EXTREMITY GAIT TRAINING AND ASSISTANCE

Ph.DDOCTOR OF PHILOSOPH

Joint Trajectory Generation and High-level Control for Patient-tailored Robotic Gait Rehabilitation

This dissertation presents a group of novel methods for robot-based gait rehabilitation which were developed aiming to offer more individualized therapies based on the specific condition of each patient, as well as to improve the overall rehabilitation experience for both patient and therapist. A novel methodology for gait pattern generation is proposed, which offers estimated hip and knee joint trajectories corresponding to healthy walking, and allows the therapist to graphically adapt the reference trajectories in order to fit better the patient's needs and disabilities. Additionally, the motion controllers for the hip and knee joints, mobile platform, and pelvic mechanism of an over-ground gait rehabilitation robotic system are also presented, as well as some proposed methods for assist as needed therapy. Two robot-patient synchronization approaches are also included in this work, together with a novel algorithm for online hip trajectory adaptation developed to reduce obstructive forces applied to the patient during therapy with compliant robotic systems. Finally, a prototype graphical user interface for the therapist is also presented

A Loosely-Coupled Passive Dynamics and Finite Element based Model for Minimising Biomechanically Driven Unhealthy Joint Loads during Walking in Transtibial Amputees

The primary objective of a prosthetic foot is to improve the quality of life for amputees by enabling them to walk in a similar way to healthy individuals. Amputees su˙er from health risks including joint pain, back pain and joint inflammation. The aim of this thesis is to develop a new computational approach to reduce the likelihood of biomechanically driven joint pain in transtibial amputees resulting from sustained exposure to Unhealthy Loads (ULs) during walking. This is achieved by developing a computational methodology to achieve a customisable sti˙ness design solution for prosthetic feet so that the occurrence of unhealthy joint loads during walking is minimised.It is assumed that the healthy population is able to spend energy most optimally during walking at all walking speeds. During walking, the force exerted by the body on the ground is measured by the ground reaction force (GRF). The GRF value is normalised with the body weight defining a dimensionless parameter . The values are similar for both legs in healthy populations but are di˙erent for the sound and a˙ected leg for amputees. A new hypothesis has been proposed in this thesis that walking is comfortable for an amputee when the di˙erence between values is minimal between the amputee and an equivalent healthy population. The values for healthy adults, as well as amputees, follow a finite number of patterns. The pattern of the values (or the GRF curve) depends on the walking speed of an individual, categorised as slow, fast or free walking. However, it is observed in the literature that free walking speed (FWS) varies over a wide range for healthy individuals (e.g. 1.1 m/s to 1.5 m/s). As a result, it was diÿcult to establish a relationship between walking speed and GRF pattern. A novel parametrised description of GRF curves for a healthy population and amputees is proposed so that a new dimensionless velocity ratio parameter and the corresponding value of the FWS can be predicted by observing the GRF pattern of a healthy adult or an amputee. A new classification approach based on the parametrised description of GRF curves, along with the dimensionless velocity ratio parameter, has been recommended for categorising very slow, slow, free, fast and very fast walking. The GRF result predictions are validated on healthy adults in an experiment conducted in a gait lab. A group of candidates who walk a lot in their daily life were specially selected for this experiment. This classification approach is used to develop a new measure of ULs based on the parametrised GRF description for healthy population and amputees. An innovative computational methodology is proposed to design an optimal sti˙ness response of a prosthetic foot that minimises the occurrence of ULs. This is achieved by transferring the roll-over shape (ROS) information of the prosthetic foot and the corresponding information for a given velocity ratio across a passive walking dynamic (PWD) and a finite element model via a newly defined form of loose coupling. A theoretical case study is presented in which an amputee walks in a gait lab with a representative C-shaped prosthetic foot. The thesis explains how the proposed novel computational methodology is able to redesign the prosthetic foot in a way that is better suited to minimising ULs. The redesign process of the prosthetic foot has led to the development of an innovative 3D printable double keel and double heel design. With the advancement of carbon reinforced polymers and additive manufacturing technology, the sti˙ness customisation methodology proposed in this thesis has the potential to create a new generation of energy-eÿcient prosthetic feet

Analysis of the backpack loading efects on the human gait

Gait is a simple activity of daily life and one of the main abilities of the human being. Often during leisure, labour and sports activities, loads are carried over (e.g. backpack) during gait. These circumstantial loads can generate instability and increase biomechanicalstress over the human tissues and systems, especially on the locomotor, balance and postural regulation systems. According to Wearing (2006), subjects that carry a transitory or intermittent load will be able to find relatively efficient solutions to compensate its effects.info:eu-repo/semantics/publishedVersio