Control unit for electric power steering apparatus
First Claim
1. A control unit for an electric power steering apparatus including a steering angle sensor for detecting a steering angle of a steering shaft and being controlled to apply a steering assist force by a motor to a steering system of a vehicle, the control unit comprising:
- a plurality of position detection sensors for outputting binary values according to a rotation position of the motor;
a relative steering angle detecting means for detecting a relative steering angle of the steering shaft from binary outputs of the position detection sensors; and
an abnormality determining means for determining that the steering angle sensor or the relative steering angle detecting means is abnormal when a difference between a change amount of the steering angle and a change amount of the relative steering angle is greater than a predetermined value to output an abnormality signal.
1 Assignment
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Accused Products
Abstract
It is an object of the present invention to provide a control unit for an electric power steering apparatus for accurately detecting an abnormality of a steering angle sensor without forming the steering angle sensor as a double system or using an expensive position detection sensor. The object is achieved by calculating a relative steering angle by using inexpensive position detection sensors disposed at a motor of the electric power steering apparatus to output binary values and comparing a change amount of an absolute steering angle detected by the steering angle sensor and a change amount of the calculated relative steering angle with each other to thereby detect the abnormality of the steering angle sensor.
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Citations
4 Claims
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1. A control unit for an electric power steering apparatus including a steering angle sensor for detecting a steering angle of a steering shaft and being controlled to apply a steering assist force by a motor to a steering system of a vehicle, the control unit comprising:
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a plurality of position detection sensors for outputting binary values according to a rotation position of the motor; a relative steering angle detecting means for detecting a relative steering angle of the steering shaft from binary outputs of the position detection sensors; and an abnormality determining means for determining that the steering angle sensor or the relative steering angle detecting means is abnormal when a difference between a change amount of the steering angle and a change amount of the relative steering angle is greater than a predetermined value to output an abnormality signal. - View Dependent Claims (2, 3, 4)
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Specification