A concept for control of indoor-operated autonomous wheelchair

The present chapter introduces a navigation algorithm for a wheelchair in semistructured home environment. The user sets the end position and orientation of the wheelchair and the controller autonomously steers the wheelchair from the current position to the goal. The algorithm includes a procedure for automatic creation of an initial map of the wheelchair surroundings that is used afterwards for composition of collision-free path from the starting point to the target. Calculation of the present wheelchair position is based on the information of the TV images from ceiling mounted cameras that detect the wheelchair in all steps of its movement toward the goal. For prevention from navigation failures in situations when wheelchair markers cannot be clearly detected by the cameras, the information about the angular rotation of the driving wheels is used for calculation of the current position. In order to set the movement task, the user refers to a wheelchair-mounted monitor where the images from all rooms are represented. After selection of the TV image from the room where the target is located, one puts the end wheelchair position and orientation by pointing them directly on the image. The information, collected by onboard-mounted range sensors during the wheelchair operation, is used for obstacle avoidance and map update. The map can be additionally corrected and modified by the user. A special simulator ROSI (RObotic SImulator) is designed for computer testing of the proposed algorithm. Finally, some design principles of the simulator and results from the initial evaluation of the algorithm with the simulation are remarked.

Online ISBN: 9783540443964