Development of a wireless sensor node based pushrim activated wheelchair controller

In this paper, the wireless sensor node technology is used to design a pushrim activated wheelchair (PAW) controller. The proposed wireless sensor node is capable of collecting user´s toques which are applied on two pushrims to generate wheelchair speed commands. In order to control a PAW smoothly, parametric sigmoid functions are developed to accelerate or decelerate wheel motors based on users´ setups. In addition, the state transitions among forward, backward, and stop of wheel motors are also well arranged. Three wireless motes are used in this system, where two of them are desired for wheel motor controllers, and the remaining one serves as a network coordinator. A supervisory control is further developed to adjust the resistance, operation time factor and left-and-right bias to meet different wheelchair manipulation purposes. Finally, a wheelchair prototype is developed based on the proposed architecture to verify our approaches.