Development and Analysis of Linkage-based Overground Gait Rehabilitation Robots

Abstract

Stroke is one of the leading causes of physical disability around the world, resulting in significant motor deficits and ultimately reduced gait performance. In order to regain or improve motor function, stroke patients will undergo rehabilitation. Current rehabilitation techniques are labour-intensive and time-consuming for both the therapist and the patient. Therefore, not all patients receive the recommended quantity and quality of rehabilitation. To improve the gait rehabilitation process, robot-assisted gait rehabilitation has been receiving increased interest over the past few years. The research in this thesis aims to demonstrate feasibility of robotic gait rehabilitation devices which are designed to be easy to use, simple and compact. The Linkage-based Gait Trainer (LGT) was the first device developed and is an overground gait rehabilitation device consisting of a four-bar linkage end-effector mechanism. The literature review suggested the design could be an effective gait rehabilitation device while minimising the components required. The design of the LGT was validated with a healthy human participant, and kinematic data showed that the device successfully constrained the user’s foot motion to a pre-defined gait trajectory. The imposed trajectory of the LGT is set by the linkage design and cannot be changed. To allow for modification to the trajectory a subsequent device (robotic Re-Link Trainer [rRLT]) was developed. The rRLT also uses a four-bar linkage, however the spatiotemporal parameters of gait, such as walking speed, stride length and cadence, can be varied to accommodate a wider range of users with different limb lengths and desired walking speeds. A trial with healthy participants was carried out to validate the rRLT’s design and its function. The results confirmed the device’s ability to vary the spatiotemporal parameter of the gait pattern the device imposes on the user. One of the limitations of both the LGT and rRLT is that the constrained gait path is not variable. To make the device available for more users with different gait trajectories, a new gait rehabilitation device with a five-bar linkage called PRO-GaiT was developed. A trial with healthy participants confirmed the ability to change and constrain different gait trajectories during walking exercises. The research in this thesis confirmed the ability of a linkage-based overground gait rehabilitation device to constrain a user’s footpath to a desired trajectory. Such devices can vary the footpath and spatiotemporal parameters of gait to accommodate many different users. The devices developed in this research could improve the effectiveness of the gait rehabilitation by potentially increasing the time and intensity of each session while reducing the number of staff required. A rehabilitation device based on this research could be compact, easy to use and low cost thus can be widely adopted by many hospitals and clinics.