JP3161303B2 - Abnormality detection device for steering angle sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting an abnormality of a steering angle sensor and, more particularly, to a device for determining whether or not the steering angle sensor is abnormal.

[0002]

2. Description of the Related Art Heretofore, it has been conventionally possible to provide slits at equal angular intervals in a rotating disk that rotates in conjunction with steering of a steering wheel of a vehicle, and detect the steering angle by detecting the passage of the slits with a photocoupler. Is being done.

For example, Japanese Patent Application Laid-Open No. 2-40504 discloses that a steering angle detected by a steering angle sensor is compared with a steering angle estimated by using a yaw rate detected by a yaw rate sensor, and a difference between the two steering angles is determined. A steering angle detection device that corrects a neutral point deviation by using the steering angle sensor to obtain an accurate steering angle is described.

[0004]

In the conventional apparatus, even if the wiring of the steering angle sensor is disconnected or short-circuited and the steering angle detection signal does not change, is the abnormality caused by the disconnection or short-circuit occurring? It is impossible to distinguish whether the steering is not actually performed. Therefore, when such an abnormality occurs, it is impossible to detect an accurate steering angle even if the neutral point is corrected, and it is not possible to know that there is an error in the detected steering angle. there were.

[0005] The present invention has been made in view of the above points,
When the amount of change in the steering angle continues to be less than the predetermined value, it is determined that the vehicle is in an abnormal state when the turning direction of the vehicle has been reversed a predetermined number of times or more. It is an object of the present invention to provide a steering angle sensor abnormality detection device capable of performing the above-described operation.

[0006]

According to the first aspect of the present invention, as shown in FIG. 1, an abnormality detecting device for a steering angle sensor M1 for detecting a steering angle of a vehicle, which detects a turning state of the vehicle. The turning direction of the vehicle detected by the turning state detecting means when the state in which the change amount of the steering angle detected by the turning angle sensor is less than a predetermined value continues for a predetermined time or more. Abnormality determination means M3 for determining that the steering angle sensor is abnormal when the number of reversals has occurred a predetermined number of times or more.

[0007] If the detected turning angle is not changed continuously for a predetermined time or more and the turning direction is reversed a plurality of times, the steering angle sensor can be regarded as abnormal. Thus, the abnormality of the steering angle sensor can be accurately detected. According to a second aspect of the present invention, in the abnormality detection device for a steering angle sensor according to the first aspect, the turning state detecting unit detects a yaw rate, and the abnormality determining unit determines that the yaw rate is equal to a predetermined value for left turning. It is determined that the turning direction has been reversed when any one of the right turn predetermined values continuously exceeds the predetermined time or more, and then the yaw rate continuously exceeds the other for the predetermined time or more.

If the yaw rate alternately exceeds the predetermined value for left turning and the predetermined value for right turning for a predetermined time or more, it is determined that the turning direction has been reversed.
It is possible to prevent erroneous determination of turning direction reversal caused by detected yaw rate noise, vibration of the yaw rate sensor due to impact, and the like.

[0009]

FIG. 2 is a plan view of a steering angle sensor disk used in the present invention. The steering angle sensor disk 10 shows only a half thereof. The steering angle sensor disk 10 is fixed with its center aligned with the rotation axis of the steering wheel, and rotates with the rotation of the steering wheel. Equiangular theta ₁ interval to a predetermined radial position near the outer periphery of the steering angle sensor disc 10 (theta _1, for example 2.25 °)
A plurality of slits 12 for detecting a steering angle are opened. Further, a predetermined angle θ ₂ (θ ₂ is, for example, 1
(3.5 °), a notch 14 for center detection is provided.

The slit 12 is detected by optical sensors (photocouplers) 20 and 21, and the cutout 14 is detected by an optical sensor (photocoupler) 22. Optical sensor 20, 2
Each of the disks 1 is only half of the interval between adjacent slits.
0, the slits 12 are detected by the rotation of the steering angle sensor disk 10, and are separated from each other in the circumferential direction of FIG.
(A), (B) The steering angle detection signals SS1 and SS shown respectively.
2 (the slit 12 corresponds to the low level). The optical sensor 22 detects the notch 14 by the rotation of the steering angle sensor disk 10 and outputs a center detection signal SSC (the notch 14 corresponds to a low level) as an origin position signal shown in FIG. I do.

The steering angle sensor disk 10 and the optical sensors 20 to 22 correspond to the steering angle sensor M1. FIG. 4 shows a schematic configuration diagram of an embodiment of the apparatus of the present invention. Optical sensor 20,
A steering angle detection signal output by each of the
Each of the center detection signals output by the electronic control circuit (EC
U) 30.

A yaw rate sensor 23 as a turning state detecting means M2 detects a yaw rate due to the rotational movement of the vehicle and supplies the yaw rate to the ECU 30. Wheel speed sensor 24-2
Each of the wheels 7 detects the wheel speed of each of the four wheels and supplies it to the ECU 30. The ECU 30 includes a central processing unit (CPU) 32,
Read-only memory (RO) storing processing programs
M) 34, a random access memory (RAM) 36 used as a work area, an input port circuit 38 including an A / D converter, an output port circuit 40, and an EEPROM 42 as a nonvolatile memory. Are connected to each other by a bidirectional bus 44. The input port circuit 38 is supplied with detection signals from the optical sensors 20 to 22, the yaw rate sensor 23, and the wheel speed sensors 24 to 27. The output port circuit 40 has an alarm 4
6 are connected.

FIGS. 5 and 6 show a flowchart of an abnormality detection routine executed by the CPU 32 as the abnormality determining means M3. This routine is interrupted at predetermined time intervals. 5, first, in step S10, the steering angle θ, the yaw rate γ, the wheel speeds V _FL , V _FR , V _RL ,
Parameters of V _RR is read.

Next, the process proceeds to step S12, where the lowest wheel speed among the four wheel speeds is equal to or higher than the predetermined speed V ₁ (for example, 10 km / h), and the steering angle θ obtained this time and the previous steering angle It is determined whether the absolute value | θ-θ _n-1 | of the deviation from the angle θ _n-1 is less than a predetermined value A (for example, 4.5 degrees). If the minimum wheel speed <V ₁ or | θ−θ _n-1 | ≧ A, the abnormality determination of the steering angle sensor cannot be performed, and the process proceeds to step S14, where the counters C ₁ , C ₂ , C ₃ , Cα and the polarity flag F _{1 are set.} , F ₂
Reset each to zero.

On the other hand, minimum wheel speed ≧ V ₁ and | θ−θ _n-1
If | <A, the process proceeds to step S16, and step S12
Counter C that measures the duration of the state that satisfies the condition
Increments ₁ by 1. Next, step S18
And the yaw rate γ becomes a predetermined value K ₁ for left turning (for example, +20 de)
g / sec). For gamma ≦ K ₁ proceeds to step S20, resets the counter C ₂ to 0, in the case of gamma> K ₁ increments the counter C ₂ for measuring the duration of the state that is gamma> K ₁ by one.

In step S24 following step S22.
Counter C_TwoIs a predetermined time t_Two(For example, 200 msec)
It is determined whether it has been obtained. C_Two> T_TwoIf step S
26 is the polarity flag F_TwoIs 1 and the positive polarity yaw rate detector
It is determined whether or not it is an_Two= 1
In step S28, the counter Cα for measuring the number of repetitions is set to 1
And the polarity flag F is incremented in step S30.
_TwoReset to zero to detect positive polarity yaw rate
This indicates that the charging has been completed.
To indicate the yaw rate detection timing
The polarity flag F ₁Is set to 1 and step S3 in FIG.
Proceed to 4.

[0017] In the case where the polarity flag F ₂ is already finished the positive polarity of the yaw rate detection timing at 0 in step S26 advances to step S32. Step S2
If C ₂ ≦ t ₂ in step 4, and if step S20 is executed, the process directly proceeds to step S34.

In step S34, it is determined whether or not the yaw rate γ is smaller than a right turn predetermined value K ₂ (for example, -20 deg / sec). For gamma ≧ K ₂ proceeds to step S36, resets the counter C ₃ to 0, gamma in the case of <K ₂ γ <K ₂
Increments the counter C ₃ for measuring the duration of the state is only one.

In step S40 following step S38
Counter C_ThreeIs a predetermined time t_Three(For example, 200 msec)
It is determined whether it has been obtained. C_Three> T_ThreeIf step S
Polarity flag F at 42₁Is 1 and the negative polarity yaw rate detector
It is determined whether or not it is an₁= 1
In step S44, the counter Cα for measuring the number of repetitions is set to 1
And the polarity flag F is incremented in step S46.
₁Reset to zero to detect negative polarity yaw rate
Indicates that the power supply has been completed.
To indicate the yaw rate detection timing
The polarity flag F _TwoTo 1 and proceed to step S50.
No.

[0020] In the case where the polarity flag F ₁ has already finished the negative polarity of the yaw rate detection timing at 0 in step S42 advances to step S48. Step S4
For 0 C ₃ ≦ t _3, and the process proceeds directly to step S50 if executing the step S36.

The count value of the step S50 the counter C _1, i.e. the lowest wheel speed ≧ 1 and _{| θ-θ n-1 |} < time of the A to determine whether more than a predetermined time t ₁ (e.g. a time of 2 sec), If C ₁ ≦ t ₁ , the processing cycle ends, and C
In the case of _1> t _1, the process proceeds to step S52. Step S5
In step 2, it is determined whether or not the number of repetitions counted by the counter Cα is equal to or greater than a specified number CONS (for example, three times). Here, if Cα <CONS, the processing cycle ends, and if Cα ≧ CONS, the process proceeds to step S54.
In step S54, the abnormality of the steering angle sensor is determined, and
Thereafter, the processing cycle ends.

Here, as shown in FIG. 7A, the steering angle change amount (Δθ = θ−θ _n-1 ) is maintained to be less than the predetermined value A for a predetermined time t ₁ or more. When the yaw rate γ shown in FIG. 7B changes, the yaw rate γ becomes a predetermined value K.
_When the period T ₁ exceeding ₁ exceeds the predetermined time t ₂ , the number of repetitions Cα is incremented as shown in FIG. Thereafter, even yaw rate γ exceeds a predetermined value K ₂ or less than a predetermined value K _1, number of repetitions Cα is not incremented if the period T _2, T ₃ does not exceed a predetermined time t _2.

Then, the yaw rate γ is equal to the predetermined value K of the positive polarity.
The next period T ₁ to more than _1, yaw rate γ period T _4, which becomes a predetermined value K less than ₂ negative polarity is incremented number of repetitions Cα is when exceeding a predetermined time t _2. Then repeat count Cα is being incremented prescribed count CONS or when the period T ₅ that the yaw rate γ exceeds a predetermined value K ₁ of the positive polarity exceeds a predetermined time t _2. Thus, the determination of the steering angle sensor abnormality is performed as shown in FIG.

If the turning direction is reversed a plurality of times, despite the fact that the detected steering angle hardly changes for a predetermined time or more, the steering angle sensor can be regarded as abnormal. Thus, the abnormality of the steering angle sensor can be accurately detected. The reason why the number of repetitions is incremented when the period in which the yaw rate γ exceeds K ₁ or the period in which the yaw rate γ is less than K ₂ exceeds the predetermined time t ₂ is to remove the influence of noise or vibration caused by an object hitting the yaw rate sensor 23. That's why. After the yaw rate γ exceeds K ₁ and the number of repetitions is incremented, the yaw rate γ
So it increments the number of iterations by less than K _2, for performing the increment of the number of repetitions only when the polarity of the positive and negative yaw rate γ is reversed,
When the vehicle is turning in a state where the steering angle is fixed, when the driver has changed the speed fueling accelerator, yaw rate or exceeds the K ₁ multiple times in the same polarity, and again becomes less than K _2, This is to prevent the increment of the repetition number from being performed each time and to reliably capture the operation state in which left and right steering is repeated.

The predetermined values K ₁ and K ₂ , the predetermined time t ₂ ,
Each of the predetermined speed V ₁ and the predetermined value A is a level that can be reliably detected in an actual vehicle, and is a value that does not cause erroneous determination. In the above embodiment, the turning state of the vehicle is detected by the yaw rate sensor 23. Alternatively, for example, the yaw rate can be obtained from the difference between the left and right wheel speeds and the vehicle speed. , The turning state of the vehicle can be detected, and the present invention is not limited to the above embodiment.

[0026]

As described above, the first aspect of the present invention provides
An abnormality detection device for a steering angle sensor that detects a steering angle of a vehicle, wherein a turning state detection unit that detects a turning state of the vehicle, and a state in which a change amount of the steering angle detected by the steering angle sensor is less than a predetermined value. Abnormality determination means for determining that the steering angle sensor is abnormal when the reversal of the turning direction of the vehicle detected by the turning state detection means has occurred a specified number of times or more when the rotation time has continued for a predetermined time or more. Have.

In the case where the detected turning angle is not changed continuously for a predetermined time or more and the turning direction is reversed a plurality of times, the steering angle sensor can be regarded as abnormal. Thus, the abnormality of the steering angle sensor can be accurately detected. The invention according to claim 2 is
The abnormality detection device for a steering angle sensor according to claim 1,
The turning state detecting means detects a yaw rate, and the abnormality determining means determines that the yaw rate continuously exceeds one of a left turning predetermined value and a right turning predetermined value for a predetermined time or more, and then the yaw rate is increased. It is determined that the turning direction has been reversed when the other has been continuously exceeded for a predetermined time or more.

If the yaw rate alternately exceeds the predetermined value for left turning and the predetermined value for right turning for a predetermined time or more, it is determined that the turning direction has been reversed.
It is possible to prevent erroneous determination of turning direction reversal caused by detected yaw rate noise, vibration of the yaw rate sensor due to impact, and the like.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a plan view of a steering angle sensor disk.

FIG. 3 is a waveform diagram of a detection signal of an optical sensor.

FIG. 4 is a schematic configuration diagram of the device of the present invention.

FIG. 5 is a flowchart of an abnormality detection routine.

FIG. 6 is a flowchart of an abnormality detection routine.

FIG. 7 is a diagram for explaining the present invention.

[Explanation of symbols]

 Reference Signs List 10 steering angle sensor disk 12 slit 14 notch 14a, 14b end 20-22 optical sensor 23 yaw rate sensor 24-27 wheel speed sensor 30 ECU 32 CPU 34 ROM 36 RAM 38 input port circuit 40 output port circuit 42 EEPROM 44 bus 46 Alarm M1 Steering angle sensor M2 Turning state detecting means M3 Abnormality determining means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01B 21/00-21/32 B62D 9/00-15/02

Claims (2)

(57) [Claims] 1. An abnormality detection device for a steering angle sensor for detecting a steering angle of a vehicle, comprising: a turning state detecting means for detecting a turning state of the vehicle; and a change amount of the steering angle detected by the steering angle sensor. When the state less than the predetermined value has continued for the predetermined time or more, it is determined that the steering angle sensor is abnormal when the turning direction of the vehicle detected by the turning state detecting means has been inverted more than a specified number of times. An abnormality detection device for a steering angle sensor, comprising: abnormality determination means. 2. The steering angle sensor abnormality detecting device according to claim 1, wherein the turning state detecting means detects a yaw rate, and the abnormality determining means determines whether the yaw rate is a predetermined value for left turning and a value for right turning. Abnormality detection of the steering angle sensor, wherein it is determined that the turning direction has been reversed when one of the predetermined values continuously exceeds the predetermined time for a predetermined time or more and then the yaw rate continuously exceeds the other for a predetermined time or more. apparatus.