JP3236486B2 - 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 Laid-Open Publication No. Sho 61-28811 discloses a steering angle detecting means for detecting a steering angle and outputting a steering angle signal, and setting a predetermined steering range around a steering position corresponding to an actual steering angle zero point. There is described a steering position detecting device including a neutral zone detecting means for detecting, and a neutral position calculating means for obtaining an average value of the steering angle signals at the time of detecting the neutral zone and outputting it as a neutral position signal.

[0004]

In the conventional apparatus, a slit provided on a rotating disk for obtaining a steering angle signal is clogged with grease or the like. If an abnormality such as skipping occurs in the angle signal, or if an abnormality occurs in the steering angle signal due to mixing of electrical noise, the accuracy of the detected steering angle decreases.

However, the conventional apparatus cannot detect an abnormality of the steering angle sensor, and has a problem that it is impossible to know a decrease in the accuracy of the steering angle due to the abnormality of the steering angle detection signal. The present invention has been made in view of the above points, and stores the steering angle at the time of the origin position signal generation, and calculates a deviation from the steering angle at the subsequent origin position signal generation of 360 degrees.
It is an object of the present invention to provide an abnormality detection device for a steering angle sensor that can detect an abnormality of a steering angle sensor by performing abnormality determination when the value is away from a value obtained by multiplying the degree by an integer, and that can detect a decrease in accuracy of the detected steering angle. Aim.

[0006]

According to a first aspect of the present invention, there is provided a steering apparatus for detecting a steering angle based on a pulse signal generated by a predetermined number per rotation of a steering member rotated by a steering operation, as shown in FIG. An abnormality detection device for a steering angle sensor, comprising an angle detection means M1 and an origin position signal generation means M2 for generating an origin position signal when the rotational position of the steering member is near the origin position. at the time
A steering angle storing means M3 for storing the steering angle detected by the Oite the steering angle detecting means, detected by the steering angle detecting means at the time point of generation of back of the origin position signal
The abnormality determining means M4 which determines that the steering angle sensor is abnormal when the deviation between the steering angle thus set and the steering angle stored in the steering angle storage means is a predetermined angle or more from a value obtained by multiplying 360 degrees by an integer. Have.

Here, if there is no abnormality in the steering angle sensor, the deviation of the steering angle from the steering angle stored in the steering angle storage means when the origin position signal is generated again is ± 360 ° × n.
(N is an integer), the steering angle at the time of the origin position signal generation is stored, and when the deviation from the steering angle at the time of the subsequent origin position signal generation is away from a value obtained by multiplying 360 degrees by an integer, an abnormality is detected. By performing the determination, an abnormality of the steering angle sensor can be detected, and it is possible to know a decrease in the accuracy of the detected steering angle.

[0008]

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 and 21 correspond to the steering angle detecting means M1.
0 and the optical sensor 22 correspond to the origin position signal generating means M2. The steering angle sensor is a disk 10 and an optical sensor 2.
0 to 22. FIG. 4 shows a schematic configuration diagram of an embodiment of the apparatus of the present invention. The steering angle detection signal output from each of the optical sensors 20 and 21 and the center detection signal output from each of the optical sensors 22 are supplied to the electronic control circuit 30.

The ECU 30 includes a central processing unit (CPU) 32
A read-only memory (ROM) 34 storing a processing program and the like, 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, It has an EEPROM 42 which is a non-volatile memory, and these are connected to each other by a bidirectional bus 44. The input port circuit 38 is supplied with detection signals of the respective optical sensors 20 to 22. An alarm 46 is connected to the output port circuit 40.

FIG. 5 shows a flowchart of an initialization routine executed by the CPU 32 as the steering angle storage means M3. This routine is interrupted at predetermined time intervals.
At the time of starting, the initial setting flag F is reset to 0. In the figure, in step S10, an initialization flag F
Is determined to be 0 or not. If F = 0 and the initialization has not been performed, the process proceeds to step S12, and if F = 1 and the initialization has been completed, this processing routine ends.

In step S12, the center detection signal SSC
Is determined to be a rise from 0 to 1, and if so, the process proceeds to step S14. In step S14, it is determined whether the rotation is right. If the rotation is right, the process proceeds to step S16. If the rotation is left, the process proceeds to step S18. The determination of the rotation direction is performed based on a change pattern of the steering angle detection signals SS1 and SS2, which will be described later with reference to FIG.

In step S16, the current steering angle θ is set to the initial right edge steering angle θ _R0 corresponding to the end 14a of the notch 14 in FIG. 2, and the initial left edge rudder corresponding to the end 14b of the notch 14 is set. The angle θ _L0 is obtained and set by equation (1). θ _L0 = θ _R0 −K (1) where K is the angle from the end 14a to the end 14b of the notch 14.

In step S18, the initial left edge steering angle θ _L0
Is set as the current steering angle θ, and the initial right edge steering angle θ _RO is obtained by equation (2) and set. θ _R0 = θ _L0 + K (2) After the above step S16 or S18, step S20
Then, 1 is set to the initial setting flag F to indicate that the initial setting is completed, and the processing routine ends.

On the other hand, in step S12, the center detection signal S
If the SC is not rising, the process proceeds to step S22, in which it is determined whether the center detection signal is falling from 1 to 0. If not, the processing cycle is terminated. If it is, the process proceeds to step S24. In step S24, it is determined whether or not the rotation is right. If it is clockwise, the process proceeds to step S18 to set the initial left and right edge steering angles θ _L0 , θ _R0 , and step S2
If 0, the flag F is set to 1. If the counterclockwise rotation is performed, the process proceeds to step S16, where the initial edge steering angles θ _R0 and θ _L0 are set, and the flag F is set to 1 in step S20, and the processing cycle ends.

Here, if the values of the steering angle detection signals SS1 and SS2 shown in FIGS. 3A and 3B are expressed as SS1 / SS2, as shown in FIG. 6, 0/0 → 0/1 → 1 / 1 → 1/0
When the state changes in the order of 0/0, the clockwise rotation is performed. In this case, the counter C is decremented by 1 every time the state changes. Also, 0/0 → 1/0 → 1/1 → 0/1 →
When the state changes in the order of 0/0, the counterclockwise rotation is performed. In this case, the counter C is incremented by 1 each time the state changes. However, in the case of 0/0 → 1/1, 0/1 → 1
In the case of / 0, 1/1 → 0/0, and 1/0 → 0/1, the value of the counter C is not changed because the rotation direction is unknown.

The value of the above-mentioned counter C is determined by the angle of the slit 12.
Multiplied by an angle interval (for example, 2.25 °) to obtain the steering angle θ.
Confuse. At this time, the counter when the vehicle is traveling straight
Value C ₀With the steering angle θ as the zero point₀And the counsel at that time
The steering angle θ shown in FIG. What
In addition, the fact that the vehicle is in a straight running state means that, for example, the steering angular velocity is
If the yaw rate change rate is less than the predetermined value B and less than the predetermined value A,
When the vehicle is full and the vehicle speed is within the specified range (medium to low speed).
It is determined that the vehicle is traveling. The above processing is performed for the steering angle sensor disk 1
0 and the sensors 20 and 21 together with the steering angle detecting means M1.
Make up.

FIG. 8 shows a flowchart of an abnormality detection routine executed by the CPU 32 as the abnormality determining means M4. This routine is interrupted at predetermined time intervals.
In the figure, in a step S30, it is determined whether or not the initial setting flag F is 1, and when F = 0, the processing routine is ended as it is. If the initial setting has been completed with F = 1, step S
Go to 32.

In step S32, the center detection signal SSC
Is determined to be a rise from 0 to 1, and if it is a rise, the process proceeds to step S34. In step S34, it is determined whether the rotation is right. If the rotation is right, the process proceeds to step S36. If the rotation is left, the process proceeds to step S38.

In step S36, the current steering angle θ is set to the right edge steering angle θ _R. Then, the process proceeds to a step S40, wherein it is determined whether or not the following three conditions are satisfied. θ _R0 ≠ θ _R and α <| θ _R −θ _R0 | <360−α (3) θ _R0 ≠ θ _R and 360 + α <| θ _R −θ _R0 | <720-α (4) θ _R0 ≠ θ _R and 720 + α | θ _R −θ _R0 | <1080-α (5) where α is a predetermined angle (for example, 4.5 degrees).

Here, the initial setting routine shown in FIG.
Edge steering angle θ_R0, Θ_L0Turn right after each is initialized
Right edge steering at the time when the center detection signal SSC is obtained at
Angle θ _RAnd the initial edge steering angle θ_R0Deviation from the specified range
Has been determined.

FIG. 9 shows the center detection signal SSC and the steering angle θ when the steering wheel is rotated at a constant speed by solid lines I and II, respectively. In FIG. 9, the expression (3) indicates that the region N
G1 is shown, the equation (4) is the area NG2, and the equation (5) is the area N
G3 is shown. That is, despite the detection of the center detection signal SSC, if the edge steering angle θ _R is in the region NG1, NG2, or NG3, the steering angle signals SS1, SS2
Can be regarded as an abnormal occurrence due to missing pulses or noise contamination.

Therefore, if the equation (3), (4) or (5) is satisfied, the process proceeds from step S40 to step S44, where abnormality of the steering angle sensor is determined, an alarm is issued by an alarm 46, and a processing cycle is performed. To end. Also,
If all of the expressions (3), (4), and (5) are not satisfied, the process proceeds to step S42 to determine whether the steering angle sensor is normal, and ends the processing cycle.

On the other hand, in step S38, the left edge steering angle θ
_LIs set to the current steering angle θ. Next, step S46
To determine whether or not the following three conditions are satisfied. θ_L0≠ θ_L And α <| θ_L−θ_L0| <360−α (6) θ_L0≠ θ_L And 360 + α <| θ_L−θ_L0| <720−α (7) θ_L0≠ θ_L And 720 + α | θ_L−θ_L0| <1080-α (8) Here, the initial edge steering angle θ in the initial setting routine of FIG.
_R0, Θ_L0After each is initialized, turn left to detect center
Left edge steering angle θ at the time when signal SSC is obtained _LAnd early
Edge steering angle θ_L0Whether the deviation from
Has been determined.

If the above expression (6), (7) or (8) is satisfied, the process proceeds from step S46 to step S44, where abnormality of the steering angle sensor is determined, an alarm is issued by the alarm 46, and processing is performed. End the cycle. Also,
If all of the expressions (3), (4), and (5) are not satisfied, the process proceeds to step S42 to determine whether the steering angle sensor is normal, and ends the processing cycle.

On the other hand, in step S32, the center detection signal S
If SC is not rising, the process proceeds to step S48, and it is determined whether or not the center detection signal is falling from 1 to 0. If it is not falling, the processing cycle is ended. If falling, the process proceeds to step S50. In step S50, it is determined whether or not the rotation is right. Step S is set to θ the current steering angle to the edge steering angle θ _L advances to step S38 if the right rotation
A determination at 46 is made. If it is counterclockwise rotation, step S3
The program proceeds to 6, where the current steering angle θ is set to the edge steering angle θ _R, and the determination in step S40 is performed. Step S40, S4
6 and thereafter are as described above.

In the present invention, if there is no abnormality in the steering angle sensor, the deviation of the left and right edge steering angles θ _L , θ _{R from} the left and right initial edge steering angles θ _L0 , θ _R0 is ± 360 ° × n (n is an integer).
When the deviation exceeds ± 360 ° × n ± α, it is determined that an abnormality has occurred. As a result, an abnormality of the steering angle sensor can be detected, and a decrease in the accuracy of the detected steering angle due to the abnormality can be known.

[0029]

As described above, the first aspect of the present invention provides
If there is no abnormality in the steering angle sensor, it is stored in the steering angle storage means.
When the origin position signal is generated again for the
The deviation of the steering angle is ± 360 ° × n (n is an integer)
To store the steering angle at the time of origin position signal generation.
After that, the deviation from the steering angle at the time of the origin position signal generation is 360
Perform an abnormality judgment when the value is away from the value obtained by multiplying the degree by an integer.
With this, the abnormality of the steering angle sensor can be detected, and the detected steering angle can be detected.
Can be known that the accuracy has decreased.

[0030]

[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 initialization routine.

FIG. 6 is a diagram showing a change pattern of a steering angle detection signal.

FIG. 7 is a diagram showing a relationship between a counter value and a steering angle.

FIG. 8 is a flowchart of an abnormality detection routine.

FIG. 9 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 30 ECU 32 CPU 34 ROM 36 RAM 38 input port circuit 40 output port circuit 42 EEPROM 44 bus 46 alarm device M1 steering angle detecting means M2 origin Position signal generating means M3 Steering angle storage means M4 Abnormality determining means

Continuation of the front page (72) Inventor Toyoharu Katsukura 1-1-1 Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. Int.Cl. ⁷ , DB name) G01B 21/00-21/32 B62D 15/00-15/02

Claims (1)

(57) [Claims] 1. A steering member which is rotated by a steering operation.
A steering angle detecting means for detecting a steering angle based on a pulse signal generated by a predetermined number of rotations; and an origin position signal generating means for generating an origin position signal when the rotational position of the steering member is near the origin position. An abnormality detection device for a sensor, wherein the steering angle detection means is provided at a time point when the origin position signal is generated.
A steering angle storing means for storing the steering angle detected by the stage, the steering angle at the time point of generation of back of the origin position signal
When the deviation between the steering angle detected by the detection means and the steering angle stored in the steering angle storage means is apart from a value obtained by multiplying 360 degrees by an integer or more than a predetermined angle, abnormality determination to determine that the steering angle sensor is abnormal. Means for detecting an abnormality of a steering angle sensor.