Development of the safe powered wheelchair controller

The purpose of the study is to develop a power wheelchair controller with safe security. This system is constructed with 2 modules: a main system and a sensors module. The micro-controller, ATMEL 89C51, is severed as a kernel of this controller. The analog signal generated from the joy stick is converted to digital signal by an ADC. This digital signal is processed by the micro-controller and output the digital values to control the right and left motors. The digital values arc converted to input voltage levels of motor drivers by DACs. The input voltage levels control the direction and speed of the powered wheelchair, Ultrasound and IR sensors are employed to be the distance detector to aid users to control the wheelchair smoothly. In forward direction, the ultrasound sensors in front of the wheelchair will detect the distance from wheelchair to obstacle to automatically control the direction and speed of the powered wheelchair. The IR sensors under the safe bars are employed to detect the vertical distance. While the IR sensor detects gaps or stairs, the IR sensors will start to cut off the power supply of the wheelchair to improve safety of users. Generally speaking, this controller is practical, low cost, safe, and stable.