Development of a Walking Assistive Service Robot for Rehabilitation of Elderly People

Abstract

In order to realize a welfare community, where elderly and disabled people can comfortably live a normal life, it is essential to develop various devices and systems, using cutting-edge science and technology. In particular, there is an urgent need for the development of a human-friendly robotic system that is flexible and adaptable enough to meet the needs of our aging population, and the needs of disabled people living within the community. For walking exercises several items of auxiliary equipment are required to help the roles of the lower limbs. For traditional walking auxiliary equipment, these can be divided into the parallel bar (with the bottom part adjusted), which supports the walker at four points, crutches, which supports the walker at two points, and the cane which supports the walker at only one point. The parallel bar consists of two bars secured at an appropriate height in parallel: it is the most stable form of walking auxiliary equipment. The walker uses them to help him or her to stand straight, and balance the body while walking exercises are undertaken. With support at four points, parallel bars generally give stability, but since they are not externally secured, falls are possible. Its shortcomings include that the user cannot walk fast, and may have difficulty in walking up a slope. Crutches and canes are more commonly used. These buttress the weight of the user, thereby assisting weakened legs and lessening the weight carried, (which may also reduce pain) to enable more natural walking. However, these traditional rehabilitation devices depend upon use by and adjustment with the upper limbs and upper body, so that the degree of weight support is inconsistent and immeasurable. Furthermore, the energy consumption required in using these devices is considerable. Equipment such as the orthopedic scooter, the bath bike, etc., reduces the energy consumption and provides a larger degree of freedom of movement. However, they do not satisfy the basic needs in terms of adjustment of supporting strength. BWS is an item of treatment equipment for rehabilitation exercises for patients with neurological damage. It was proposed in 1985 to assist the easy attainment of the natural walking pattern In 1987, a cat that had its spine completely split was treated in a walking exercise program by using the weight support system repeatedly on a treadmill and it was then discovered that several aspects of walking in humans is similar to walking www.intechopen.com Service Robot Applications 140 in cats. However, before this method was used with human patients, a study was conducted with 10 ordinary people who had no mobility problems, walking on a treadmill with 70% or more of their weight supported. In this experiment there was no abnormal walking and up to 70% of BWS was found to be helpful. In rehabilitation BWS is now considered the most convenient method to overcome the difficulties in walking exercises (T. Patients with neurological problems have found exercises with BWS significantly better than exercising with no weight support. Walking in water would have a similar effect, but that, of course, would be very inconvenient. Barbeau(1987) designed and manufactured a broad range of rehabilitation devices. One involves the patient walk on the treadmill with an upper frame (that is adjusted by hand), supporting the weight of the patient. A robot assistant, AID-1 (T. I. REHABOT, a device that lessens the patient's weight by the same method as AID-1, enables the patient to walk on a circular route. In the beginning, a parallel bar is used with this equipment, to allow patients who have orthopedic or central nervous system problems (which make the exercise more difficult) to use the equipment. The walking capability of healthy individuals is tested with 60% or more BWS. Norman (1995) redesigned the equipment, such that the treadmill and the BWS device used hydraulic power. When holding on the parallel bars to walk, the degree of