Author:

Keywords:

haptic guidance, navigation assistance, force feedback, Science & Technology, Technology, Automation & Control Systems, Engineering, Electrical & Electronic, Robotics, Engineering

Abstract:

This article introduces a set of novel haptic guidance algorithms that provide intuitive and reliable assistance for electric wheelchair navigation through narrow or crowded spaces. The proposed schemes take hereto the nonholonomic nature and a detailed geometry of the wheelchair into consideration. The methods encode the environment as a set of collision-free circular paths and, making use of a model-free impedance controller, ‘haptically’ guide the user along collision-free paths or away from obstructed paths or paths that simply do not coincide with the motion intended by the user. The haptic feedback plays a central role as it establishes a fast bilateral communication channel between user and wheelchair controller and allows a direct negotiation about wheelchair motion. If found unsatisfactory, suggested trajectories can always be ‘overruled’ by the user. Relying on inputs from user modeling and intention recognition schemes, the system can reduce forces needed to move along intended directions. Thereby avoiding unnecessary fatigue of the user. A commercial powered wheelchair was upgraded and feasibility tests were conducted to validate the proposed methods. The potential of the proposed approaches was hereby demonstrated.