JP2519426Y2 - Vehicle steering angle detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a steering angle detection device for a vehicle, and more particularly to a steering angle detection device for improving reliability of steering angle detection.

(Problems to be Solved by Conventional Techniques and Inventions) In recent years, some vehicles such as four-wheeled vehicles are equipped with a system for performing required control according to a steering angle.
In such a system, a sensor for detecting a steering angle, which is generally called a steering angle sensor, is used.

A steering angle sensor of this type usually has a configuration in which a steering angle signal is extracted by using a pulse signal, and for example, an optical pulse generator is used to respond to rotation during steering wheel operation. In general, a pulse signal is obtained, and a steering angle information is obtained by a counter based on the pulse signal. With such a configuration, since the pulse is used as the processing signal of the detection system, it is possible to obtain the required angle resolution accuracy, which has the advantage that the detection accuracy can be improved.

However, when an abnormality occurs in the pulse generation system or the pulse signal processing system, proper control according to the steering angle cannot be performed,
Therefore, it is necessary to detect the presence or absence of an abnormality in order to prevent the malfunction of the system due to the abnormality of the detection system. In particular, when the number of pulses indicates the steering angle amount, if noise superimposition occurs, the counter output will show something different from the actual steering angle amount. If there is a problem, it is extremely important to be able to detect it properly. Among them, an abnormality that causes a sudden change in the steering angle signal, such as a failure in the counter system, causes a sudden change in the control state of the system, and in such a case, rapid detection is highly necessary. .

The present invention has been made in view of the above points,
An object of the present invention is to provide a rudder angle detecting device capable of detecting an abnormality that causes a sudden change in the detection output in the rudder angle detection system, and thereby improving the reliability of rudder angle detection. .

(Means for Achieving the Object) In order to achieve the above object, the present invention provides an angle pulse generating means for generating an angle pulse corresponding to a turning angle in accordance with the rotation of a steering wheel, and a turning means based on the angle pulse. A rudder angle detecting device for a vehicle, comprising: a counter for obtaining rudder angle data; and rudder angle changing speed detecting means for detecting a rudder angle changing speed based on a difference between a current value and a previous value of the counter while the vehicle is traveling. And the output of the steering angle change speed detection means is the first
If the steering angle detection system is abnormal, the output of the steering angle change speed detection means continues for a predetermined time, and the second predetermined determination value (< First
Second abnormality determining means for determining that the steering angle detection system is abnormal when the steering angle detecting system becomes smaller than the predetermined determination value.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

 FIG. 1 shows an overall configuration diagram of an apparatus according to an embodiment of the present invention.

In this embodiment, an optical transmissive sensor is used as the steering angle sensor of the steering wheel, and as a sensor assembly, as shown in FIG. 1, a movable body that moves in accordance with the rotation of the steering wheel is shown. In the case of, a rotating disk (sensor disk) 1, a photosensor unit 2 for angle pulse,
The photo sensor unit 3 for the reference pulse is provided.

The rotating disk 1 is attached to the shaft 4 so that the rotating disk 1 can rotate integrally with the steering shaft 4 as the steering shaft 4 rotates. In the vicinity of the outer peripheral edge of the disk 1, a plurality of through holes (slits) 11 are provided over the entire circumference in the circumferential direction. These through holes 11 on the disk surface are the duty ratio of the pulse signal obtained from the photosensor unit 2 (ON, ON, when the disk is rotated, the light is transmitted by each through hole 11 and the light is blocked by the through hole disk surface portion. Off ratio) is just 50%
(See FIG. 4), the width of the through hole 11 in the circumferential direction and the interval between the adjacent through holes 11, 11 are set.

As shown in FIGS. 1 and 2, the photosensor section 2 arranged so as to face the passing locus of the 11 rows of through holes is composed of two sets of photosensors 21 and 22, One set of photosensors 21 has one light emitting portion 21a and one light receiving portion 21b which are arranged to face each other with the disc 1 interposed therebetween. The other set of photosensors 22 also includes a pair of light emitting units 22 having the same configuration as described above.
a and a light receiving section 22b are provided, but these two sets of photosensors
21 and 22 are installed by shifting the positions in the circumferential direction of the disk 1 so that a 90 ° phase difference (see FIG. 4) is provided between the pulse signals obtained from each of them and having a duty ratio of 50%. .

When the steering wheel is turned to the right or left from its operation reference position (neutral position) to turn the vehicle to the right or left, the disk 1 rotates to the right as the steering shaft 4 rotates (clock in FIG. 1). A pulse is generated every time the through hole 11 passes through the photo sensor unit 2 when rotating in the directional direction or rotating in the left direction (rotating in the counterclockwise direction).
Therefore, the number of pulses obtained from the photo sensor unit 2 depends on the turning amount of the wheel, and the photo sensor unit 2
Angle information is included in the output signal of. Further, not only the rotation angle of the steering wheel but also the steering angular velocity information is included in the output signal. That is, the number of generated pulses per unit time indicates the angular velocity (rotation speed). Further, since the two sets of photosensors 21 and 22 are used as described above, it is possible to check the clockwise and counterclockwise directionality by utilizing the phase difference between the outputs, and therefore the rotation direction information is also included. ing. Details of the detection of the directivity will be described later.

In this embodiment, the rotary disk 1 having the 11 rows of through holes is formed.
The photo sensor unit 2 constitutes a means for generating an angle pulse corresponding to the turning angle according to the rotation of the steering wheel.

On the disk surface of the rotary disk 1, a single (one) through hole 12 is further provided at an inner peripheral position of the through hole 11 row. The above-mentioned photosensor portion 3 for the reference pulse is arranged at a predetermined position facing the rotation trajectory of the through hole 12, in the illustrated case, below the photosensor portion 2 alongside the photosensor portion 2. Photo sensor part 3
Similarly to each of the sensors 21 and 22 of the photo sensor unit 2, as shown in FIG. 2, the photo sensor unit 2 includes a pair of a light emitting unit 3a and a light receiving unit 3b which are opposed to each other with the rotating disk 1 interposed therebetween.

The light emitting portions 21a, 22a, 3a and the light receiving portions 21b, 22b, 3b in each photo sensor portion 2, 3 may be, for example, a light emitting diode (LED) or a phototransistor, respectively. The specific arrangement and fixation of each light emitting diode and phototransistor is
For example, it can be carried out by using an appropriate housing 5 having a substantially U-shaped cross section for covering a part of the disk 1 as shown by a chain double-dashed line in FIG.

When the photosensor unit 3 for the reference pulse is installed side by side with the photosensor unit 2 in the vertical direction as described above, the setting of the disc 1 on the steering shaft 4 is as shown in FIG. Attach the disk 1 to the shaft 4 as described above. That is, the rotation position of the steering shaft 4 when the steering wheel is in the operation reference position (the state where the vehicle moves straight) is set to the reference position (0 °), and in such a state, a single through hole is provided for the photo sensor unit 3. Make settings so that 12 are exactly opposite. With this setting, the photo sensor unit 3 is provided when the steering wheel comes to the center of the steering wheel.
The light from the light emitting portion 3a enters the light receiving portion 3b through the through hole 12 and the output of the light receiving portion 3b becomes a high level. When the light is rotated clockwise or counterclockwise from the reference position 0 °, the output of the light receiving portion 3b is output. Switches to low level. Therefore, when the steering wheel is operated, a pulse signal is obtained from the photo sensor unit 3 every time the reference position of 0 ° is passed.

Also, when the lock-to-lock of the steering wheel exceeds one rotation as in a four-wheeled vehicle, for example, 2.5 rotations, the steering wheel operation angle (lock angle) is 450 ° on each side, so 360 ° clockwise ( The single through-hole 1 is used even when operated one rotation) and 360 ° counterclockwise (one rotation).
2 is opposed to the photo sensor unit 3 as in the state shown in FIG. Therefore, even at these times, the high level signal is output from the photo sensor unit 3.

The light receiving section 3b of the photo sensor section 3 is connected to an electronic control unit (hereinafter referred to as ECU) 6, and the output signal from the photo sensor section 3 is a reset (RST) signal.
It is supplied to CU6.

In the present embodiment, the photo sensor unit 3 constitutes a means for generating a reference pulse at a predetermined steering angle.

The rudder angle sensor system that detects the rudder angle is further equipped with a counter IC7.
Is provided. The photosensor unit 2 for the angle pulse is connected to the counter IC7. The counter IC7 is composed of a counter that receives angle pulses and converts angle data. For example, the photosensor unit 2 includes two sets of photosensor units 21 and 2.
If 2 is used, as shown in FIG.
It is composed of a D-type flip-flop 71 and an up / down (U / D) counter 72.

In the figure, the D-type flip-flop 71 has a data input terminal D and a clock input terminal CK. The up / down switching terminal U / D of the up / down counter 72 is connected to, for example, the Q output terminal of the D-type flip-flop 71.

The D-type flip-flop 71 is a flip-flop whose output state maintains the state of the data one bit time before, and reads the information given to the data input terminal D when a clock pulse is given, and the next clock pulse It has the function of accumulating until given. Therefore, when a clock pulse is input to the clock input terminal CK and the data input of the data input terminal D is at high level, the Q output is at high level until the next clock pulse is input.
Thereafter, similarly, if the data input is in the high level state at the time of reading by each clock pulse, the high level signal continues to be transmitted from the Q output terminal. On the contrary, if the data input is at the low level when the clock pulse is input, the Q output is at the low level until the next clock pulse is input, and the data is read when the data is read by each clock pulse. If the input is in the low level state, the low level signal is continuously transmitted.

Of the outputs of the two sets of photosensors 21 and 22 of the photosensor section 2, one of them is supplied to the data input terminal D, and the other is supplied as a clock pulse to the clock input terminal CK. In this embodiment, for example, a photo sensor
The output of 21 is input to the data input terminal D, and the output of the photosensor 22 is input to the clock input terminal CK.

As described above, the output pulses of the photosensors 21 and 22 are pulse signals each having a duty ratio of 50% as shown in FIG. 4, and both have a phase difference of 90 °. When the handle is turned to the right ((a) in the figure,
The phase relationship is reversed between (b)) and the case of turning to the left ((c) and (d) in the figure). That is, in the case of clockwise rotation,
The pulse from the photo sensor 22 has a 90 ° phase lag with respect to the pulse from the photo sensor 21. Therefore, in this state, the state of the D input at the time of rising of the clock, that is, the high level state is output to the Q output terminal.
When turning clockwise, the high level signal is continuously output as the Q output.

On the other hand, in the case of counterclockwise rotation, the phase relationship is opposite to that described above because the pulse on the photosensor 22 side has a 90 ° advancing phase, and the state of the D input at the rise of each clock is low level. In the case of, the Q output is always a low level signal. Thus, the directionality of clockwise or counterclockwise rotation can be detected depending on whether the Q output is high level or low level, and the Q output is input to the up / down counter 72 as a control signal for up-counting or down-counting switching. .

One of the outputs of the photosensors 21 and 22 is applied to the count terminal C _NT of the up / down counter 72. The application to the count terminal C _NT is performed immediately after the pulse train shown in FIG. 4 or by multiplying the pulse train (for example, 2 by a multiplying means constituted by an appropriate logic circuit).
Double) and supply. The up / down counter 72 counts up or down the number of pulses of the pulse train supplied to the count terminal C _NT according to the Q output, and outputs the count value. The count output represents angle information when the steering wheel is operated to steer the wheels, and also indicates the angle with directionality.

That is, for example, if the Q output is up-counted when it is at the high level and is switched to the down-count when it is at the low level, the count value is increased when it is clockwise, and the count value is rotated when it is counterclockwise. Goes down. Therefore, if the contents of the up / down counter 72 are set to 0 when the reference position is 0 ° described above, for example, in the case of clockwise rotation, when the steering wheel is turned by a predetermined amount, the corresponding count is made. The value up is taken out as an output, and if it is further turned to the right from there, the count value increases by that amount. Further, by switching back from the reference position 0 ° to the right, the input to the D-type flip-flop 71 is switched to the state shown in FIGS. 4 (c) and 4 (d) from the switching back point, and the Q output is output. Changes to a low level, the up-down counter 72 starts down-counting from the count value at the time of switching back, and when the steering wheel is turned to the left by the same amount, that is, when it returns to the reference position 0 °, the count value Returns to zero.

 The operation in the counterclockwise direction is similar to the above.

Therefore, the change in the count output represents the change in the steering angle, and the up count and the down count are switched depending on the direction around 0.

In this way, the counter IC7 obtains the steering angle data based on the input angle pulse and supplies it to the ECU6.

Further, a vehicle speed sensor 8 for detecting the speed of the vehicle is connected to the ECU 6, and the vehicle speed sensor 8 supplies a vehicle speed signal according to the vehicle speed to the ECU 6.

The ECU 6 shapes the various input signal waveforms supplied and corrects the voltage level to a predetermined level, etc. The input circuit 6a, the central processing unit (CPU) 6b, and the steering angle detection described later executed by the CPU 6b. It is composed of a storage means 6c for storing various calculation programs including a system abnormality determination program, calculation results, etc., and an output circuit 6d. The ECU 6 is connected to the controlled unit 9 that uses the output of the present steering angle detection device. The present apparatus can be applied to general vehicle control systems that require a steering angle sensor, and thus the above-mentioned controlled object may be arbitrary. For example, the controlled part 9 may be an actuator for changing the hardness of the suspension according to the steering angle, or may be one used for controlling four-wheel steering.

A control signal is sent to the controlled portion 9 which is to be controlled according to the steering angle via the output circuit 6d.

Further, the ECU 6 includes, as a part of the abnormality processing unit when the steering angle detection system is abnormal, an alarm means 10 for displaying an LED, for example.
Is connected, and when an abnormality is discriminated according to the abnormality discrimination program, a control signal can be output from the output circuit 6d to the alarm means 10 in order to inform the abnormality. In addition, the ECU6 uses the counter IC7 to reset the counter.
A counter reset signal is output to the reset terminal R of the up / down counter 72 through the output circuit 6d.

FIG. 5 shows a flow chart of the abnormality determination program for the steering angle sensor system executed in the CPU. This subroutine is executed each time a TDC signal pulse (a pulse obtained at a predetermined crank angle position for every 180 ° rotation of the crankshaft of the engine) is generated or at regular time intervals.

First, in step 501, every time the program is executed, the RST ₃ signal that is the output of the photosensor unit 3 for the reference pulse and the output count value CNT of the up / down counter 72 that indicates the steering angle are read, and the RST ₃ It is determined whether or not the signal is at high level (step 502). When the answer to step 502 is affirmative (Yes), that is, when the RST ₃ signal is at high level, the process proceeds to step 503 and subsequent steps from the following viewpoints.

The operating angle is 0 ° when the RST ₃ signal goes high.
In the state of 360 °, that is, when the single through hole 12 faces the photosensor portion 3 at the reference position 0 ° as shown in FIG. Since 12 appears when facing the photo sensor unit 3, such a state may be a straight traveling state or a state in which the steering wheel is just turned 360 °. Therefore, if a positive determination result is obtained in step 502, it is first determined whether the vehicle speed V is higher than a predetermined value V _MIN (for example, 5 km / h) (step 503), and the answer is negative. (No), that is, when the vehicle speed V is below the predetermined value V _MIN ,
The processing after step 514 described below is executed.

When the answer to step 503 is affirmative (Yes), that is, when V> V _MIN is satisfied and the vehicle is traveling at a speed exceeding the predetermined value V _MIN , the following determination is performed. That is, when the running state of the vehicle is detected in step 503, it is determined in subsequent step 504 whether the running state (yaw rate) of the vehicle is substantially straight (3 degrees / second or less). Here, the determination can be made by comparing the detected value Y representing the yaw rate with a predetermined value Y _G. For the yaw rate, for example, a gyroscope may be used, and the left and right wheel speeds of the driven wheels of the vehicle may be used. It may be estimated by the difference.

If the answer to step 504 is negative (No), the process proceeds to step 514 and subsequent steps, and if the answer is affirmative (Yes), the loop is executed for a predetermined time t ₁ (for example, 120 seconds, that is,
2 minutes) It is determined whether or not the vehicle has continuously passed, and the step 50
If the answer to step 5 is negative (No), the process proceeds to step 506 and thereafter.

That is, when the vehicle speed exceeds the predetermined value V _MIN and the predetermined time t _{1 has not} passed from the time when the RST ₃ signal was switched to the high level, the following processing is executed.

First, when proceeding to step 506, the absolute value | CNT | of the value of the up / down counter 72 is a predetermined value α (for example, 2 °).
Is smaller than.

When the RST ₃ signal is high level,
When the answer to 506 is affirmative (Yes), that is, when | CNT | <α is satisfied and the CNT value is within ± α °, the through hole 12 faces the photosensor portion 3 at the reference position 0 °. This is the case. Therefore, in this case, the counter reset signal is transmitted, the up / down counter 72 is reset (step 507), and the processes of step 514 and the later described are executed. Thus, the contents of the counter 72 are forcibly cleared at the reference position of 0 °, so that the counter output can be set to 0 when the reference position of 0 ° is taken. The predetermined value α applied in step 506 is for setting a certain allowable width in the case of making the above determination, and an error of this extent is unavoidable.

If the answer to step 506 is negative (No), that is, if the absolute value of the count value | CNT | exceeds the predetermined value α, whether the CNT value is within the range of 360 ° ± α ° or not. (Step 508) and if the answer is affirmative (Yes), that is, if the value of the up / down counter 72 is within 360 ° ± α °, this is clockwise or left from the reference position 0 °. This means that the RST ₃ signal becomes high level because the through hole 12 faces the photo sensor portion 3 in the state of making one rotation around. That is, if the steering angle detection system is normal, turning the steering wheel one turn to the right or left causes up-counting or down-counting,
The count value should represent 360 °, so
When a pulse is obtained from the photo sensor unit 3 in a state other than CNT | <α, it can be considered that the normal counting operation is performed. Therefore, at this time, the count value CNT at that time is reset without resetting the counter 72.
While holding, proceed to step 514 and thereafter.

On the other hand, it is not | CNT | <α, and | CNT | = 360
When the high-level signal appears as the RST ₃ signal even though the condition is not ° ± α °, that is, when the answer to step 508 is negative (No), the count value CNT is affected by noise or other effects. It is determined that an abnormality has occurred for some reason (step 509), a reset signal is output to the up / down counter 72 (step 510), and this program ends. As a result, when the count value of the counter 72 that represents the steering angle when the reference pulse is generated shows a value other than 0 ° and 360 ° (specifically, a value within a range including the constant allowable width α), It is possible to determine that the angle sensor system is abnormal,
Anomalies due to counting errors, noise superposition, etc. are detected.

The processing for the abnormality in steps 509 and 510 can include processing such as lighting of the LED by the alarm means 10 so that the driver can know the occurrence of the abnormality. Further, the above-mentioned forced counter reset at the time of abnormality is to prevent the steering angle signal from being output at the time of abnormality. That is, the function of the up / down counter 72 (the function of obtaining the angle information based on the input angle pulse) is stopped, and its output is fixed to a constant value (0). Therefore, it is possible to avoid the control based on the incorrect steering angle signal.

On the other hand, when the answer to step 505 is affirmative (Yes), that is, when the vehicle speed is being output, when the high level signal is continuously output as the RST ₃ signal for a predetermined time t ₁ or more, in other words, the predetermined time t _{When the} RST ₃ signal has never changed to the low level within ₁ , the above steps 509 and 510 are executed to end the program. If the steering angle detection system is normal, the above state means that the steering wheel angle has not changed from the 0 ° or 360 ° position for a long period of time t ₁ while the vehicle is running, When the vehicle is being driven at a certain vehicle speed, the state where the steering wheel angle is not changed does not continue. Therefore, such a case, it is possible to see that some abnormality has occurred reference pulse generation system of the steering angle detection system indicates that it is a state that can not function normally, the predetermined time t ₁ has elapsed The condition is judged to be abnormal.

Returning to step 502, if the answer is no (No), that is, if the RST ₃ signal is at low level, the following step
At 511, it is determined whether or not the loop has continuously passed for a predetermined time t ₂ (for example, 360 seconds, that is, 3 minutes), and at step 512, the absolute value | CNT | of the count value CNT is the predetermined value C.
_It is determined whether or not it is larger than _MAX . The predetermined value G _MAX is
It is set according to the lock angle of the steering wheel of the vehicle to be applied. For example, if the lock-to-lock is 2.5 rotations, it is set to 450 °.

If all the determination results of the above steps 511 and 512 are negative (No), the process proceeds to step 514. However, if any of the determination results is affirmative (Yes), it is determined to be abnormal (step 513), and the program To finish.

The step 511 is based on the viewpoint that a high-level reset signal should normally come in as an output signal of the photo sensor unit 3 within a predetermined time t ₂ while the vehicle is traveling at a certain vehicle speed or higher. It was provided by
When the low level state of the RST ₃ signal continues for a predetermined time t ₂ or more, it is considered that there is an abnormality in the steering angle detection system from the above point.

Further, if the answer in step 512 is affirmative (Yes), it means that the output of the up / down counter 72 represents a value equal to or larger than the actually operable steering wheel angle. Therefore, also in this case, it is decided that the count value CNT is abnormal due to the fact that the rudder angle detection system is in a state where normal detection corresponding to the rudder angle cannot be performed for some reason such as noise or other influences. .

In step 514, calculates the amount of change in the count value CNT ΔCNT (difference between the CNT _n during CNT _n-1 and the current loop of the previous loop), then the absolute value of the ΔCNT | ΔCNT | is a steering angle change determination The first predetermined discriminant value ΔG ₁ ^{+ of} (for example, 500 ° / sec × 1.
5, preferably 700 ° / sec.) (Step 515). When the answer to step 515 is affirmative (Yes), that is, when | ΔCNT |> ΔG ₁ ⁺ is satisfied and the steering angle change speed is significantly higher than that during normal operation, it is determined to be abnormal (step 513). That is, in this case, | ΔCNT | is ΔG
^Exceeding ₁ ⁺ means that the steering wheel angular position at the time of reading the CNT value in the previous loop changed almost instantaneously from the previous angular position to a considerably different angular position. However, such a change cannot be caused by a normal operation of the steering wheel by the driver, and therefore, there is a high possibility that some abnormality occurs in the steering angle detection system, particularly an abnormality such as a failure of the processing system including the counter IC7. Therefore, in the above case, it is considered that there is an abnormality.

The processing in step 513 is similar to the above-described abnormality determination when the counter value is not at the predetermined value when the reference pulse is generated,
Anomaly display and other processing can be included.

When the answer to step 515 is negative (No), that is, | ΔC
When NT | does not exceed ΔG ₁ ⁺ , it is considered that there is no abnormality in the above meaning, and the process proceeds to step 516 and thereafter. Step 5
At 16, whether or not the vehicle speed V is higher than a predetermined value V _MIN ,
In step 517, the amount of change ΔCNT obtained in step 514 is calculated.
Absolute value | ΔCNT | of the second predetermined discriminant value ΔG ₂ ⁺ (for example, 3
Angle / second).

The answer to step 516 is negative (No), that is, the vehicle speed V is the predetermined value V.
_{When MIN} or less, or when the answer to step 517 is negative (No),
That is, in any case when the change in the count value exceeds ΔG ₂ ⁺ , this program is terminated as it is. On the other hand, as a result of the determination in each of the steps 516 and 517, when the answer is affirmative (Yes), that is, when V> V _MIN is satisfied and | ΔCNT | <ΔG ₂ ⁺ is satisfied, the following step 5
At 18, it is determined whether or not the loop has been continuously passed for a predetermined time t ₁ . The monitoring of the elapsed time from the time when the above two conditions are satisfied in step 518 is performed using, for example, an internal timer of the CPU 6b.

Result of discrimination at step 518, if the answer is negative (No) before starting measurement after a predetermined time t ₁ has elapsed, although ends the abnormality without the considered by the program, the answer to obtain affirmative (Yes) In other words, the state that the speed of change of the steering angle is less than ± ΔG ₂ ⁺ value continuously occurs, and this is the predetermined value.
When the vehicle speed exceeds V _MIN and the vehicle continues for a predetermined time t ₁ or more, it is determined to be abnormal at that time (step 513).

In the processing of step 515, when the degree of change in the steering angle is extremely large, it is immediately judged to be abnormal because it does not appear in the actual steering operation. On the other hand, in the processing in steps 516 to 518, the degree of change in the steering angle is also used as a judgment element for determining whether or not there is an abnormality, but here, the case where the degree is extremely small is handled. That is, | ΔCNT | is ΔG ₂
The state of less than ⁺ means that the handle angle position at the time of each reading at the time of the previous loop and the current loop has hardly changed. This situation is
It does not happen at all within a certain time. For example, in a straight traveling state of the vehicle, the driver will operate so as to keep the steering wheel in the neutral position without keeping the straight traveling.
It is possible for CNTs to assume less than ± ΔG ₂ ⁺ .

However, normally, the condition of | ΔCNT | <ΔG ₂ ⁺ does not continuously appear for a long time. For example, if the vehicle turns a little to the right even when going straight, the steering wheel will turn to the left to return it. Since this operation is repeated after turning off, in normal operation, | ΔCNT | is ΔG ₂ ⁺
In case of above (that is, the answer in step 517 is negative (No))
If it becomes), this is the case. Therefore, if
When the condition of ΔCNT | <ΔG ₂ ⁺ continues, the steering angle detection system,
In particular, there is a high possibility that an abnormality such as a failure of the processing system including the counter IC7 has occurred.

Therefore, as described above, V> V _MIN and | ΔCNT | <ΔG ₂
^{When the +} condition is satisfied, it is determined whether or not there is an abnormality depending on whether or not the condition continues for a predetermined time t ₁ .
If it continues, it will be considered abnormal.

The abnormality determination in these steps 516 to 518 is basically the same as that in the above-mentioned steps 502 to 505, but in the former case, since the change amount of the count value based on the angle pulse is checked, It is especially effective for detecting abnormalities in the counter system.

In the present embodiment, the structure of the rudder angle sensor is an optical and transmissive type, but it may be a reflective type, and the sensor itself is not limited to the optical type.

Further, as the moving body in the sensor, a disk-circular movement type is used, but this is not limited to this structure, and may be a linear moving type, for example.

Further, as shown in FIG. 5, in the example shown in the figure, other abnormality determinations are explained in addition to the abnormality determination according to the present invention, but it goes without saying that only the abnormality determination according to the present invention may be performed. In addition to this, it is not hindered to use any one or more other types of abnormality determination in combination.

(Effect of the Invention) According to the present invention, it is provided with an angle pulse generating means for generating an angle pulse corresponding to the turning angle according to the rotation of the steering wheel, and a counter for obtaining the turning angle data based on the angle pulse. In a steering angle detecting device for a vehicle, a steering angle changing speed detecting means for detecting a steering angle changing speed based on a difference between a current value and a previous value of the counter while the vehicle is traveling, and the steering angle changing speed detecting means. Of the steering angle detection system is abnormal when the output of the steering angle detection system is equal to or greater than the first predetermined determination value, and the output of the steering angle change speed detection means continues for a predetermined time, Since the second abnormality determining means for determining that the steering angle detection system is abnormal when it becomes smaller than the predetermined determination value (<first predetermined determination value) is provided, the abnormality of the steering angle detection system is detected. Can be, especially of the count value of the constant counter Since the degree of change is monitored to determine whether or not there is an abnormality, it is possible to quickly detect an abnormality that causes a sudden change in the steering angle signal, and improve the reliability of steering angle detection. Can be planned.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle steering angle detecting device according to an embodiment of the present invention, and FIG. 2 is a diagram showing the generation of each photosensor unit in FIG.
FIG. 4 is an explanatory view showing an example of the arrangement of the light receiving section, FIG. 3 is a block diagram showing an example of the internal configuration of the counter IC of FIG. 1, and FIG.
FIG. 5 is a timing chart used for the explanation, and FIG. 5 is a flowchart showing an example of an abnormality determination program for the steering angle detection system. 1 ... Rotating disk, 2, 3 ... Photo sensor part, 4 ... Steering shaft, 6 ... ECU, 7 ... Counter IC, 11, 12 ... Through hole.

Continuation of the front page (56) Reference JP 61-81278 (JP, A) JP 61-202114 (JP, A) JP 61-201109 (JP, A) JP 61-200422 (JP , A)

Claims (1)

(57) [Scope of utility model registration request] 1. A steering angle detection device for a vehicle, comprising: an angle pulse generating means for generating an angle pulse corresponding to a turning angle according to a rotation of a steering wheel; and a counter for obtaining turning angle data based on the angle pulse. In the device, a steering angle change speed detection unit that detects a steering angle change speed based on a difference between a current value and a previous value of the counter while the vehicle is traveling, and an output of the steering angle change speed detection unit are the first output. A first abnormality determination means for determining that the steering angle detection system is abnormal when the steering angle detection system is greater than or equal to a predetermined determination value, and a second predetermined determination value (<second And a second abnormality determining means for determining that the steering angle detection system is abnormal when the steering angle detection system becomes smaller than a predetermined determination value of 1.).