MOTOR-DRIVEN POWER STEERING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a motor-driven power steering device provided with an excellent steering wheel return property even at a low and high friction factor road and improved in an steering wheel return property in particular on a low friction factor road. SOLUTION: A steering control device 19 is provided with a central processing device (CPU) 20, An ECU 18 for an ABS(Antilock Brake System) calculates a road friction factorμand inputs it to a CPU 18. The CPU 20 computes a steering wheel rotation angular speedωbased on a motor current Im and a voltage Vm between motor terminals. A current output value to a motor 7 is increased so that during low speed running, on the lowμroad side where the road friction factorμis low, a steering wheel return force is increased to a value higher than that on the highμroad side wherein the road friction factorμis high.