A Driving Assistance System for a Manual Wheelchair using Servo Brakes

Abstract

We propose a novel intelligent wheelchair based on the passive robotics. Our proposed assistive wheelchair consists of a frame, casters, wheels and servo brakes. Our wheelchair system estimates the trajectory its user wants using the characteristic of the row motion and realizes the estimated tracks by controlling a torque of its servo brake. Our system requires no actuators, and its mechanism is simple and low cost. There is no risk by malfunction of servomotors and patients can use it intuitively because they use our wheelchair passively with their own intentional force. Our key ideas are two topics. One is the development of a passive-type assistive wheelchair which is suitable for practical use. The other key topic is a novel driving assistance algorithm with estimation of its user's intention. For realizing this estimation, we use a minimum jerk trajectory model, which expresses a typical human movement. Our proposed system compares a beginning part of row motion by the user and this trajectory model, and estimates a whole row motion which will be operated. Using our proposed system, the user can drive our wheelchair with a natural feeling. We test our proposed assistance system by the experiments with our prototype and verify its effectiveness.