Development of Navigation Support System for the Powered Wheelchair

本研究提出了一种提高户外电动轮椅安全性的方法，并研制了一种智能电动轮椅样机。基于传感器融合技术设计开发了原型系统。该系统采用GPS、16个超声波传感器、摄像机和操作感应开关。16种超声波传感器分为两组，苏联（超声波传感器半环形）和美国（超声波传感器阵列）。每组由8个超声波传感器组成。设S_j表示第j个超声波传感器，S_0, S_1，…， S_7在苏联实现，S_8, S_9，…在美国，S_<15>。整个系统工作在手动模式（m模式）和自主模式（a模式）下。用户只要握住手柄，系统就会进入手动模式。在这种模式下，用户通过控制手柄和电源开关直接操作轮椅。系统观察用户的操作是否正确，并通过扬声器发出的语音信息提供帮助信息。当系统检测到用户的操作有危险时，会提醒用户注意并紧急停机。例如，当红灯亮时，用户试图继续移动，或者当用户的操作与障碍物发生碰撞时，系统会紧急停车，并通过扬声器发出语音信息通知用户。当用户释放句柄时，系统进入自治模式。在这种模式下，由GPS生成粗略的路由图，并提供给系统。系统计算移动方向，确定转弯点，并根据这些信息和更新的路线图进行自定位。电动轮椅会自动向目的地移动。这主要包括：根据GPS，苏联，美国，摄像机的信息，检测障碍物并进行避障，检测十字路口的人行横道，捕捉红绿灯的变化并确定正确的操作。少

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