This paper describes new results with a Reactive Shared-Control system that enables a semi-autonomous navigation of a wheelchair in unknown and dynamic environments. The purpose of the reactive shared controller is to assist wheelchair users providing an easier and safer navigation. It is designed as a fuzzy-logic controller and follows a behaviour-based architecture. The implemented behaviours are three: intelligent obstacle avoidance, collision detection and contour following. Intelligent obstacle avoidance blends user commands, from voice or joystick, with an obstacle avoidance behaviour. Therefore, the user and the vehicle share the control of the wheelchair. The reactive shared control was tested on the RobChair powered wheelchair prototype  equipped with a set of ranging sensors. Experimental results are presented demonstrating the effectiveness of the controller.
Pires, Gabriel, and Urbano Nunes. “A Wheelchair Steered through Voice Commands and Assisted by a Reactive Fuzzy-Logic Controller.” Journal of Intelligent and Robotic Systems 34, no. 3 (July 1, 2002): 301-314.