Selecting a best compromise direction for a powered wheelchair using PROMETHEE

Research is described that determines the direction that a powered wheelchair will take, using the Preference Ranking Organization METHod for Enrichment of Evaluations II (PROMETHEE II). This is the first time that this sort of decision making has been used in this type of application. A user suggests a desired direction and speed, and the decision-making system suggests a safe direction for a wheelchair. The two are mixed and the wheelchair then tends to avoid obstacles. The inputs are from ultrasonic sensors and a joystick and the final direction is a mix of the desired direction and a direction that moves the wheelchair away from obstacles. The whole system helps disabled wheelchair users to drive their powered wheelchairs. It uses a systematic decision-making process and this paper presents the process and a new way of selecting a best compromise direction. Sensitivity analysis is employed to explore potentially suitable directions as uncertainty and risk may be present. A suitable direction is selected that provides a robust solution. The user is able to over-ride the suggestions by the PROMETHEE II system by holding the joystick in a position.