Design of a novel low-speed gait rehabilitation device incorporating a synthesized geared five-bar mechanism

Abstract

People with difficulty walking due to a stroke or neurophysiological gait deficit require gait rehabilitation. Recent research indicates that the optimal speed range for gait rehabilitation of such patients is less than 0.4 m/s. The design of a novel low-speed gait rehabilitation device based on a single degree of freedom (DOF) geared five-bar mechanism is presented in this paper. For this purpose, a natural gait meta-trajectory is generated using the recently acquired low-speed gait data suitable for human walking. A less-bulky single-DOF geared five-bar mechanism is synthesized and adjusted by applying the accurate and robust shadow robot control (SRC) synthesis method. Therefore, a practical and easily controlled gait rehabilitation device is designed, which can be mounted on any commercial treadmill and enables the patient to walk as close as possible to a normal gait. This device applies to a wide variety of individuals with different physiologies due to the mechanism’s adjustability, provided by the profile blending algorithm method. This method generates a set of continuous and speed-dependent gait trajectories for various individuals. The proposed device is inherently safe and easy to control due to the limited motion range of the single-DOF mechanisms and the use of a single actuator. Furthermore, because it only has two points of contact with the body (at the hip and the ankle), it takes less time for the user to don and doff.