| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power steering device capable of producing suitable steering wheel reversing torque at any time after the driver's action to start the vehicle. SOLUTION: At least until the time when a steering wheel neutral positionθ<SB>O</SB>as a result of learning by a neutral position learning unit 241 is outputted for the first time, steering wheel reversing torque T<SB>R</SB>is determined in accordance with steering wheel speedω<SB>H</SB>. This speed valueω<SB>H</SB>is calculated through a steering wheel speed estimation unit 242, based on steering wheel torqueτand motor revolution angleθ<SB>M</SB>. If the steering wheel reversing torque T<SB>R</SB>is determined in accordance with the steering wheel speed valueω<SB>H</SB>in this way, the desired steering wheel reversing torque can be outputted even in a control blind zone. After at least the first learning is completed, more preferably after the accuracy of the learned steering wheel neutral positionθ<SB>O</SB>is sufficiently raised, in the subsequent control, the steering wheel reversing control demonstrating sufficient steering wheel reversing performance even on a low friction road surface such as a frozen road surface is executed on the basis of the steering wheel angleθ<SB>H</SB>. COPYRIGHT: (C)2005,JPO&NCIPI |
