Power-Assisted Wheelchair With Gravity and Friction Compensation

In this paper, a gravity compensated power-assisted wheelchair (GCPAW) is proposed, which will climb a hill, and stop, and make as a delicate movement in the middle of the hill as it can do on a flat surface. To climb the hill, the proposed GCPAW compensates for the parallel component of the force of gravity (the force that causes acceleration or deceleration) on a hill. A tilt sensor measures the angle of the inclined plane and electric clutches automatically connect and disconnect drive mechanisms with the wheels. The GCPAW also compensates for friction in the drive mechanism that would cause additional resistance. The rider propels the GCPAW in the same way that he/she would propel a manual wheelchair, but the mechanism compensates for both gravity and the friction. Additionally, overcompensation for the friction helps the rider's propulsion, so that with the same propulsion force the rider travels further than in a manual wheelchair, resulting in an easier movement for the rider.