Kinematic design of a footplate drive mechanism using a 3-DOF parallel mechanism for walking rehabilitation device

Abstract

Recently, facilities with the special intention to help people who lack walking ability or even sit in the wheel chair could be seen everywhere. However, in the hospitals, rehabilitation devices, which are used for people to regain their body functions right after some health problems, are very limited, and even the existing robots have not shown sufficient evidence to prove they are useful, low cost, or easy to handle to be used as a regular rehabilitation method. In this research, a 3-DOF parallel mechanism training device as a compact foot drive mechanism for the gait rehabilitation of walking-disabled patients was developed for solving these sorts of problems. The requirements and constraints were obtained through interviews with medical doctor, physical therapists and related researchers. The composition of this proposed training device is: patients can be supported by a harness system with their feet fastened onto two separated programmable footplates. Based on the preprocessed walking data captured from healthy individuals, reference motion for the footplate can be determined and used to calculate the specifications of the footplate drive mechanism. As the foot drive mechanism, a planar parallel mechanism with 3-DOF was selected. Its dimensional synthesis was carried out taking into consideration the workspace and motion transmissibility, and a prototype of the machine was designed and built in the end. Comparison between the walking data and mechanism s analysis indicated that it is possible for the machine to generate natural walking patterns, which will be further proved with a prototype in the future.Ke words : Gait ehabilitation, Parallel echanism, Workspace, Motion ransmissibility, User entered esign IntroductionWith the increasing average lifespan, facilities of special intention to help the elders who lack walking ability could be seen everywhere. The rehabilitation devices, in the hospitals, for them to regain their body functions right after some health problems are still far from enough, even the existing robots have not shown very sufficient evidence to prove they are useful, easy to handle, and good enough to be used as a regular rehabilitation method. Currently, physical therapists provide the main recovering treatment, which are very labor intensive especially for gait rehabilitation. Normally, it takes a number of forms, but repetition of the actual walking motions is the most important one. The need for high quality therapists brings heavy economic burden to hospitals especially in a country short of human resources.When we imagine rehabilitation for patients who tore Achilles' tendon or broken lower limb bones, and had taken surgical operation, its current protocol is separated in-between early phase in which range of the damaged joint is recovered, and mid-term phase in which whole lower limb is moved so that coordinated motion among several joints without giving significant load for each joint, and later gait training phase in which patients walk on flat ground (at first, then ...

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