Development of Navigation Support System for the Powered Wheelchair

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This research proposed a method to improve the safety of the outdoor powered wheelchair, and developed a prototype intelligent powered wheelchair. The prototype system is designed and developed based on the sensor fusion technology. The system employs GPS, 16 ultrasonic sensors, video camera and operation sensing switches. 16 ultrasonic sensors are divided into two groups, USSR (ultrasonic sensor semi-ring) and USA (ultrasonic sensor array). Each group consists of 8 ultrasonic sensors. Let S_j represent the j-th ultrasonic sensor, S_0, S_1, ..., S_7 are implemented on USSR, and S_8, S_9, ..., S_<15> on USA.The whole system works on manual mode (M-mode) and autonomous mode (A-mode).As soon as the user holds the handle, the system turns into the manual mode. In this mode, the user operates the wheelchair directly by controlling the handle and power switch. The system watches whether the user's operation is appropriate or not, and provide the helpful information by the voice message from … More the speaker. If the system detects that the user's operation is dangerous, it will call the user's attention and make an emergency stop. For example, if the traffic light is red and the user tries to move continuously, or if the user's operation will cause collision with an obstacle, the system will bring to an emergency stop and inform the user by the voice message from speaker.When the user releases the handle, the system turns into autonomous mode. In this mode, the rough route map is created by GPS and is provided to the system. The system calculates the moving direction, determines the turn points, and performs the self-localization according to this information and the up-dated route map. And the powered wheelchair moves toward the destination autonomously. This mainly includes : detecting the obstacles and performing the obstacle avoidance, detecting the pedestrian crossing at the intersection and catching the change of the traffic light and determining the correct operation, according to the information from GPS, USSR, USA, and video camera. Less