Motion Control of Wearable Walking Support System with Accelerometer Based on Human Model

Many countries of the world including Japan will become a full-fledged aged society. According to report in Japan, the elderly population aged 65 years or over in Japan will number 33 million and will account for more than 25 percent of the population. We have to support the elderly for independence in old age so that a variety of lifestyles is possible. With the development of the robot technologies, robotics researchers have developed various kinds of human assist robot such as walking aid system and manipulation aid system for supporting the elderly. Especially, the ability to walk is one of the most important and fundamental functions for humans, and enables them to realize high-quality lives. Many researchers focused on a walker-type support system, which works on the basis of the physical interaction between the system with wheels and the user. Walkers are widely used by the handicapped because they are simple and easy to use. Fujie et al. (1998) developed a power-assisted walker for physical support during walking. Hirata et al. (2003) developed a motion control algorithm for an intelligent walker with an omni-directional mobile base, in which the system is moved based on the user’s intentional force/moment. Wandosell et al. (2002) proposed a non-holonomic navigation system for a walking-aid robot named Care-O-bot II. Sabatini et al. (2002) developed a motorized rollator. Yu et al. (2003) proposed the PAMM system to provide mobility assistance and user health status monitoring. Wasson et al. (2003) and Rentschler et al. (2003) proposed passive intelligent walkers, in which a servo motor is attached to the steering wheel and the steering angle is controlled depending on environmental information. Hirata et al. (2007) developed The RT Walker which has passive dynamics with respect to the force/moment applied. It differs from other passive walkers in that it controls servo brakes appropriately without using any servo motors. Many researchers have considered improving their functionality by adding wheels with actuators and controlling them based on robot technology (RT), such as motion control technology, sensing technology, vision technology, and computational intelligence. But, the size of the walker-type system is large and the user has to use the both hands for moving it. On the other hand, recently, many robotics researchers focused on wearable walking