MOTOR CONTROL METHOD OF A MOTOR DRIVEN POWER STEERING SYSTEM CAPABLE OF IMPROVING THE OPERATING FEEL OF A STEERING HANDLE AND OPERATING STABILITY BY VARYING STEERING EFFECT COMPENSATING TORQUE ACCORDING TO A GRADIENT OF A ROAD SURFACE

摘要

PURPOSE: A motor control method of a motor driven power steering system is provided to improve operational convenience, steering feel, operating stability of a steering handle by varying an auxiliary torque of a motor when a vehicle travels on an inclined road and providing the optimum steering assistant force. ;CONSTITUTION: A motor control method of a motor driven power steering system comprises the steps of: sensing a tilt angle of a chassis using a tilt angle sensor while a vehicle is running(S10); operating a gradient of a road surface on the basis of the sensed tilt angle, judging whether or not the operated gradient is an upward gradient, and if the gradient of the road surface is an upward gradient, reducing a motor torque inversely proportional to the size of the gradient(S20~S50); and if the gradient of the road surface is a downward gradient, increasing the motor torque proportional to the size of the gradient(S60).;COPYRIGHT KIPO 2011