APPLICATION OF PID METHOD TO CONTROL TRACTION ON THE VEHICLES THROUGH CONTROLLING THE BRAKE MOMENT AT THE TWO DRIVING WHEELS

Abstract

A vehicle differential is a device that divides engine power between the two driving wheels and allows the wheels to rotate at different speeds when the vehicle moves on the road. The speed difference depends mainly on the grip between the wheels and the road surface. When the traction acting on both driving wheels is equal,the differential will distribute traction equally, helping the vehicle move stably on a straight road. However, if one of the two driving wheels rolls on a slippery road, the differential will distribute more engine power to this wheel. As a result, the vehicle’s motion is unstable, engine power is lost, the vehicle cannot move. To solvethe problem, using a limited-slip differential, an active differential or a traction control system is considered an optimal solution. This study uses the brake moment acting on the skidding wheel to redistribute the engine power at the two driving wheels and uses the PID method for traction control at the drive wheels. Survey results show the effectiveness of the designed controller.