Electric power steering control device
AssigneeMazda Motor Corporation
InventorMasaki CHIBA
Life of this patent
Estimating the term…
Abstract
Filters output a vibration-suppression gain for suppressing resonance of a sub frame or shimmy by performing a filter processing on a rotational angle of a motor. The filters have respective frequency characteristics that a gain becomes a maximum magnitude and a phase advances by 90° at a cut-off angle frequency. The cut-off angle frequency of the filter is fixedly set at a resonance frequency of the sub frame. The cut-off angle frequency of the filter is variably set in accordance with a tire rotation frequency. A gain adder adds the respective gains of the filters and outputs an added magnitude to a correcting mechanism as a vibration-suppression gain. The correcting mechanism corrects a motor torque set by an assist map by using the vibration-suppression gain outputted by the gain adder.
Claims2
An electric power steering control device, comprising:
- a motor to apply an assist torque to a steering device;
- a torque detector to detect a steering torque applied by a driver;
- a setting mechanism to set a motor torque to be outputted to the motor based on the steering torque detected by the torque detector;
- a rotational angle detector to detect a rotational angle of the motor;
- a filter processor to output a vibration-suppression gain for suppressing resonance of a vehicle-body member and a vibration due to a tire rotation by performing a filter processing on the rotational angle of the motor detected by the rotational angle detector;
- and
- a correcting mechanism to correct the motor torque set by the setting mechanism by using the vibration-suppression gain outputted by the filter processor so as to suppress resonance of the vehicle-body member and the vibration due to the tire rotation,
- wherein said filter processor comprises a first filter which has a frequency characteristic that a gain becomes a specified magnitude and a phase advances by 90° at a cut-off angle frequency which is fixedly set at a resonance frequency of a specified vehicle-body member,
- a second filter which has another frequency characteristic that a gain becomes a specified magnitude and a phase advances by 90° at a cut-off angle frequency which is variably set in accordance with a tire rotation frequency which is changeable according to a vehicle speed, and
- a gain adder which adds the gain of said first filter and the gain of said second filter and outputs an added magnitude to said correcting mechanism as said vibration-suppression gain outputted by the filter processor.
Dependencies are inferred from the claim text.