| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power steering device capable of improving a steering feeling by determining accurately whether operation is in a steering wheel turning condition. SOLUTION: The electric power steering device has an assist characteristic memory 22 in which a fundamental assist characteristic is stored and a shift amount computation part 24 which varies and sets a shift amount when the fundamental assist characteristic is shifted for acquiring a virtual corrective assist characteristic on the basis of a steering angular velocity, a vehicle speed, and steering torque and its differential value. An assist torque target value setting part 21 sets a target value for assist torque complying with a corrective assist characteristic by searching it in the assist characteristic memory 22 on the basis of the steering torque and the shift amount. An electric motor M is put under drive control in conformity to an assist torque target value. The shift amount is made zero at the time of cut-in steering and decided so that a greater steering assist force than in the case of the fundamental assist characteristic is obtained at the time of keeping steering and returning it. Whether the operation is in the cut-in steering condition or not is determined on the basis of the steering torque T and steering torque differential value T'. COPYRIGHT: (C)2005,JPO&NCIPI |
