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US 7,444,217 B2Granted
Electric power steering system
AssigneeJtekt Corporation
InventorYuuki Matsuoka
Life of this patent
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Abstract
A configuration is provided in which detected torque values detected by a main torque sensor and a sub-torque sensor in such a state that a predetermined torque including zero is applied are captured, a calculation of a torque difference is repeated a plurality of number of times, an average value of an absolute value of a torque difference which is calculated each time is obtained, this average value is written to be stored in an EEPROM, and a threshold value used for the failure determination is corrected based on the stored value.
Claims3
An electric power steering system comprising:
- primary and secondary torque sensors for detecting a steering torque applied to a steering member;
- a difference calculator that calculates a difference between detected torque values detected by the primary and secondary torque sensors a predetermined number of times in such a state that a predetermined steering toque is applied;
- an average value calculator that calculates an average value of results of calculations made by the difference calculator;
- a threshold value corrector that corrects a threshold value based on the average value calculated by the average value calculator;
- and
- a failure determining unit that performs a failure determining operation for determining whether or not the primary torque sensor fails based on a result of a comparison between a difference between detected torque values detected by the primary and secondary torque sensors and the corrected threshold value is performed during an assist control operation in which a steering assist motor is controlled to be driven based on a detected torque value detected by the primary torque sensor.
3 more elements
Dependencies are inferred from the claim text.