Development and Control of the Personal Cart for an Elderly Person

Abstract

This paper describes a personal cart for an elderly person and its control. The cart actively supports walking of an elderly person by himself/herself so that he/she can go out freely. The control system is synthesized to make the cart drive in accordance with gaits of an operator. The developed computer-controlled personal cart has four wheels and its controlling devices. The interval of its two front wheels is narrow, and the interval of the rear wheels is wide. Its structure looks like a three-wheeler. The two front wheels are driven by a DC-motor. An infrared radiation sensor measures the distance between the cart and the operator. The proposed system makes the cart maintain the distance between the personal cart and an operator at a certain level so that it can reduce the workload of the operator, who is walking on a slope with some baggage. It is not easy to describe the dynamic characteristics of the cart by a mathematical model, including its changing characteristics due to the driving environments such as the condition of roads and/or baggage. Furthermore, the cart system should be a human friendly system, because it is used by an elderly person. Therefore, the controller is synthesized based on a fuzzy theory. The proposed controller consists of two fuzzy controllers for driving and stopping the cart. The controller for stopping can stop the cart certainly as the cart does not access to the operator too much. The performances of the proposed system were tested in various conditions. Good performances of the control were also obtained independently of the condition of the road. Therefore, the proposed system is conceivable to be useful for the assisting of the walking.