| 摘要 |
PURPOSE: A motor driven power steering device operating variable rack stroke and a method thereof are provided to varies rack stroke without additional hardware by adding a VRS(Variable Rack Stroke) control logic unit in an existing motor driven power steering device. CONSTITUTION: An electric steering device(100) operating variable rack stroke comprises a sensor signal input unit(6), a VRS operating button(12), a MDPS(Motor Driven Power Steering) logic unit, a VRS control logic unit(16), a switching unit(14), a subtractor(22), and a motor control unit(10). A sensor signal input unit inputs sensor signals like vehicle speed, slop, steering angle, and a torque into the device. The MDPS logic unit calculates steering torque value. The VRS control logic unit calculates a VRS control value. The switching unit switches the output signals of the sensor signal unit by the control signal from VRS control button manipulations to the VRS control logic unit. The subtractor calculates the difference of the output value from the MDPS logic unit and the output value of the VRS control logic unit. The motor control unit restricts the steering angle by receiving the torque output value from the subtractor.
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