Monday, 8 October 2012

Motion control of walking assistant robot based on comfort

an article by Aolin Tang and Qixin Cao (Shanghai Jiao Tong University, China) published in Industrial Robot: An International Journal volume 39 Issue 6 (2012)


A walking assistant robot can help elderly people walk around independently, which could improve the life quality of the elderly and benefit our ageing society. Ensuring the elderly person’s walking comfort with such a robot is very important. At present, the majority of walking assistant robot research does not focus on this field. The purpose of this paper is to examine the requirements of comfortable walking and outline the design of a motion control algorithm for a walking assistant robot, Walkmate III, based on comfort.
During walking, the walking assistant robot should be able to capture the intent of user, guide the user and move at the same pace as the user. Usually, force or haptic interface is used to detect the user’s walking intention. The motion control system then transforms the forces applied by the user into the robot’s motion. By surveying the elderly people at a nursing home, the authors find that this transformation is important to the walking comfortableness and should be carefully designed. In this paper, the model of walking assisting process with such kind of walking assistant robot is derived at first. Based on this model, a new motion control algorithm is then designed.
The elderly hoped that, in all topographic conditions, only small forces were needed to drive the walker during walking. Also, good manoeuvrability was also very important for a walker, to offer the user comfort, which meant the walking assistant robot should be able to respond to the input forces quickly and precisely. Currently widely-used motion control algorithms cannot satisfy all those requirements. In this paper, a new motion control algorithm is proposed, which can get a fast and precise response to the input forces and the input forces needed to drive the robot are kept at a preferred small level, so that the user will not feel tired during walking. Furthermore, by modifying, force feedback can be realised to improve the comfortableness of walking.
Practical implications
The availability of walking assistant robot with improved walking comfortableness might encourage a wider adoption of robotics in our daily life. It could also benefit our ageing society by improving the life quality of the elderly and reducing the pressure deriving from nursing labour shortages.
This paper is of value to engineers and researchers developing walking assistant robots for the elderly people.
And possibly to advisers working with disabled people. It is not only the ageing population that has difficulty with walking!

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