Interpreting hand tremor with an expert system to assist with steering a powered wheelchair

Simple expert systems are presented that will allow more people to use powered wheelchairs. The systems interpret hand tremor and provide joystick position signals. Signals are mixed with ultrasonic sensor data to identify potentially hazardous situations and assist users to find a safe course. Results are discussed from a series of timed tasks completed by users using a joystick. They suggest that the amount of sensor support should be varied depending on circumstances and skill. Drivers completed progressively more complicated courses both with and with-out sensors and the most recently published systems are used to compare results. The new expert systems consistently out-performed the most recently published systems.