JPH0577961B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for determining the straight-line steering position of a steering wheel in a vehicle.

[Conventional technology]

Conventionally, in vehicles, etc., a steering sensor is constructed by coaxially attaching a sliding contact type variable resistor to the steering shaft, and a divided voltage ( An analog voltage signal) is obtained as a sensor output, and various controls are performed based on this sensor output.

In such a steering sensor, since the steering wheel rotates 3 to 4 times in a lock-to-lock motion, the sensor output is not a continuous quantity, and is shown in Fig. 2a.
A sawtooth voltage waveform like the one shown in Fig. 3 occurs repeatedly. That is, when the steering wheel is rotated clockwise from the straight-ahead steering position (point N in Figure 2 a), the steering rotation angle increases from 0° in the positive direction, and as the rotation angle increases, the sensor output increases. gradually rises. Then, when the steering rotation angle reaches +180°, the sensor output reaches the maximum voltage value.
The level decreases from V _nax to the minimum voltage value V _nio , and after that, the minimum voltage value is lowered every time the handle is rotated clockwise.
Gradually increases from V _nio to the maximum voltage V _nax and the maximum voltage value
A sawtooth sensor output whose level drops to the minimum voltage value V _nio at V _nax occurs repeatedly. Further, when the steering wheel is rotated counterclockwise from the straight steering position as a starting point, the steering rotation angle increases from 0° in the negative direction, and the sensor output gradually decreases as the rotation angle increases. Then, when the steering rotation angle reaches -180°, the sensor output level increases from the minimum voltage value V _nio to the maximum voltage value V _nax , and from then on, the maximum voltage value increases with every counterclockwise rotation of the steering wheel. A sawtooth sensor output is repeatedly generated in which the level gradually decreases from V _nax to the minimum voltage value V _nio and increases to the maximum voltage value V _nax at the minimum voltage value V _nio .

When performing various controls in a vehicle based on such sensor outputs, a comparison reference voltage V that is smaller than the maximum voltage value V _nax and larger than the minimum voltage value V _nio is used.
A method has been proposed in which the comparison reference voltages V1 and V2 are set (V1>V2), and the rotational direction and position of the handle are determined based on outputs that increase and decrease the comparison reference voltages V1 and V2. That is, the comparison reference voltage V
The sensor output gradually increases beyond 1, the sensor output rapidly falls from the maximum voltage value V _nax to the minimum voltage value V _nio , and the sensor output gradually increases beyond the comparison reference voltage V2. The rotation and position of the up/down counter can be known, and an up signal is sent out at the time of transition to each mode to increment the count value in the up/down counter. In addition, the sensor output that gradually decreases below the comparison reference voltage V2, the minimum voltage value
The counterclockwise rotation and position of the handle can be determined by the sensor output that suddenly rises from V _nio to the maximum voltage value V _nax and the sensor output that gradually decreases below the comparison reference voltage V1. A down signal is sent out at the time of transition to the up/down counter, thereby decreasing the count value in the up/down counter.

[Problem that the invention seeks to solve]

However, according to such conventional methods of detecting the rotational direction and position of the handle, when the up-down counter makes a miscount, there is no means to correct the error in the count value, and the accumulation of the error causes problems. As a result, there was a problem that the system malfunctioned.

Furthermore, the sensor output at the straight-ahead steering position is equal to the sensor output generated for each rotation of the steering wheel in the clockwise and counterclockwise directions starting from the straight-ahead steering position, and there is a deviation of one rotation from the true straight-ahead steering position. Therefore, there is a risk that a steering position shifted by one rotation may be determined to be a straight steering position and various controls may be performed.

[Means for solving problems]

The present invention has been made in view of the above-mentioned problems.The present invention has been made in view of the above-mentioned problems. As the rotation angle of the rotating body increases in the clockwise and counterclockwise directions, the count value in the counter means increases and decreases, and the origin position located at each rotation of the rotating body is detected. After detecting all of the odd number of different origin positions located in the rotatable range of the body, the origin position where the comparison order of the count values in the counter means becomes the center order is determined by straight steering of the steering wheel. It is determined that the location is the location.

[Effect]

Therefore, according to the present invention, when all of the odd number of different origin positions located in the rotatable range are detected, the origin position in the center order is determined as the straight steering position of the steering wheel in the vehicle. .

〔Example〕

Hereinafter, the straight-ahead steering position determining method according to the present invention will be explained in detail. FIG. 1 is a circuit configuration diagram showing an embodiment of the straight steering position determination method according to the present invention,
This is an example of application to a cornering lamp system in a vehicle. In the figure, reference numeral 1 outputs an analog voltage signal as shown in Figure 2a in conjunction with steering wheel steering clockwise (hereinafter referred to as rightward direction) and counterclockwise (hereinafter referred to as leftward direction). A steering sensor is sent out, 2 is a processing circuit that processes an analog voltage signal sent out from the steering sensor 1, and 3 is a power source.

The steering sensor 1 is composed of a sliding contact type variable resistor 11.
The connection position of the output terminal 1a with respect to the output terminal 1a can be changed in conjunction with the steering wheel. That is, when the steering wheel is in the straight steering position, the divided voltage (analog voltage signal) generated at the output terminal 1a
The connection position of the output terminal 1a to the variable resistor 11 is set so that the voltage applied to both ends of the variable resistor 11 via the constant voltage power supply 21 is approximately 1/2. The analog voltage signal generated at the output terminal 1a of the steering sensor 1 is
Comparators 221 and 2 in processing circuit 2
The comparison reference voltage V2 determined by resistors R1 and R2 and the comparison reference voltage V1 determined by resistors R3 and R4 are set to the non-inverting input terminals of comparators 221 and 222. ing. In this embodiment, the comparison reference voltage V1 is higher than the voltage value V0 of the analog voltage signal generated at the straight-ahead steering position by -60 degrees in terms of steering rotation angle, and the comparison reference voltage V2 is higher than V0 in terms of the steering rotation angle. It is set lower by -60°. and,
The outputs of the comparators 221 and 222 are input to the input terminals 23A and 23B of the decoder 23, and when the decoder 23 receives a "0" level signal to both its input terminals 23A and 23B, its output is When the level of the terminal 23a is set to the "1" level and signals of the "0" and "1" levels are input, the level of the output terminal 23b is set to the "1" level, and both signals of the "1" level are input. When this occurs, the level of the output terminal 23c is set to "1" level.

Then, the output terminal 23a of the decoder 23 is R.
It is connected to the set terminal and the reset terminal of the S flip-flop circuits 241 and 243, and when the output terminal 23a reaches the "1" level, the one-shot multivibrator 253 continues for a predetermined period of time and sends a signal to one end of the AND gates 262 and 265. It is designed to send out a one-shot signal of level 1. In addition, the output terminal 2 of the decoder 23
3b is connected to the reset terminal and set terminal of the R.S flip-flop circuits 241 and 242, and when the output terminal 23b reaches the "1" level, the one-shot multivibrator 252 continues for a predetermined period of time, and the AND gate 263 and 26
A one shot signal of "1" level is sent to one end of the 6. Furthermore, the decoder 23
The output terminal 23c is connected to the reset terminal and set terminal of the R.S flip-flop circuits 242 and 243, and the output terminal 23c is set to "1".
When the level is reached, the one-shot multivibrator 251 continues for a predetermined time and the AND gate 2
A one-shot signal of "1" level is sent to one end of the terminals 61 and 264.

On the other hand, the Q output and output of the flip-flop circuit 241 are connected to the AND gates 261 and 264.
The Q output and output of flip-flop circuit 242 are input to the other ends of AND gates 262 and 265, and the Q output and output of flip-flop circuit 243 are input to the other ends of AND gates 263 and 266. It is now being entered. And gate 261
-263 and the outputs of AND gates 264-266 are input to each input terminal of three-input OR gates 271 and 272. Then, the output power of the OR gates 271 and 272 is applied to the up input terminal 27u of the up/down counter 27.
and down input terminal 27d, and the up/down counter 27 increments or decrements its count value every time a "1" level signal is input to its input terminal 27u or 27d. A digital signal corresponding to the count value is sent to decoders 28 and 29. and decoders 28 and 29
receives this digital signal and sends it to its output terminal 28.
Predetermined output terminals from a to 28i and 29a to 29o are selected and their levels are set to "0" and "1" levels. That is,
At point N in FIG. 2a, the count value in the up/down counter 27 is set to zero, and at this time
9 selects its output terminals 28e and 29h,
Only the levels of the output terminals 28e and 29h are set to the "0" level and the "1" level. And up/down counter 27
Each time the count value increases by 1, the decoder 28 sets the output terminal to the "0" level to 28.
The output terminals of the decoder 29 are incremented sequentially from e to 28d, 28c, .
...29a and so on. Also, each time the count value in the up/down counter 27 goes down by one from zero, the decoder 2
8 connects the output terminal to "0" level from 28e to 2.
8f, 28g...28i and so on, and the decoder 29 sets the output terminal at "1" level from 29h to 29i, 29j...29o.
It is gradually being postponed. Note that the decoder 2 also performs countdown after countup or countup after countdown.
It goes without saying that the output terminals at the "0" and "1" levels in the decoder 8 and the decoder 29 are successively carried down or carried up to the adjacent output terminals. The output terminals 28a to 28d of the decoder 28 are connected to the inverter 2.
91 to the output terminal 2a of the processing circuit 2;
8f to 28i are connected to the output terminal 2b via an inverter 292. And this output terminal 2
When a and 2b reach the "1" level, the unillustrated headlight installed on the right side of the front of the vehicle (hereinafter referred to as the right lamp) and the unillustrated headlight installed on the left side of the front of the vehicle (hereinafter referred to as the right lamp) are activated. , the left lamp) rotates in the rightward and leftward directions.

On the other hand, the output terminals 29a to 29g of the decoder 29
And the output of 29i to 29o is an AND gate 30
It is designed to be input to one end of a to 30g and 30i to 30o, and the AND gates 30a to 3
0d, 30f, 30g, 30i, 30j, 30l
The output terminal 23 of the decoder 23 is at the other end of ~30o.
The output of b is input. Also,
Output terminals 29d, 29f, 29 of decoder 29
The outputs of g, 29i, 29j, 29l are branched to AND gates 30p, 30q, 30r, 30
It is designed to be input to one end of s, 30t, and 30u. In addition, the AND gates 30a to 30d,
30f, 30g, 30i, 30j, 30l~30
The output of o is from the R/S flip-flop circuit 31a~
31d, 31e, 31f, 31g, 31h, 31
It is input to the set terminals of flip-flop circuits 31a, 31b and 31c, and the other terminals of the Q output AND gates 30p, 30e and 30q, and the Q output of flip-flop circuits 31j, 31k and 31l. The outputs are input to the other ends of AND gates 30t, 30k and 30u. and gate 3
The outputs of 3-input AND gates 321 and 322 are input to the other ends of 0r and 30s, and flip-flop circuits 31d and 31 are connected to the input ends of AND gates 321 and 322, respectively.
The outputs of f, 31h, 31e, 31g, and 31i are input. And gates 30p, 30e, 30q, 30r, 30
The outputs of s, 30t, 30k, and 30u are input to an 8-input OR gate 33, and when the output of the OR gate 33 reaches the "1" level, the one-shot multivibrator 254 continues for a predetermined period of time. A one-shot signal of level "1" is sent out, and in response to this one-shot signal, the count value in the up/down counter 27 is reset and returned to zero. Furthermore, the one shot signal sent out by the multivibrator 254 is
55, and the multivibrator 255 is activated at the rising edge of this input one shot signal to send a one shot signal of level "1" to the reset terminals of the flip-flop circuits 31a to 31l. It's getting old.

Next, the operation of the vehicle cornering lamp system configured as described above will be explained. That is,
It is now assumed that the automobile is traveling straight ahead and the steering wheel is at the straight ahead steering position (point N in Figure 2a). At this time, the up/down counter 27
The count value at is zero, and only the output terminal 28e of the decoder 28 is at the "0" level. That is, output terminals 28a to 28d and 2
8f to 28i are in the "1" level state, and therefore the output levels of the output terminals 2a and 2b are inverted by the inverters 291 and 292 to become the "0" level. That is, at this time, the irradiation directions of the right lamp and the left lamp do not change and remain facing the front. Also, at this time, since the voltage value of the analog voltage signal sent out by the steering sensor 1 is V0, the output of the comparator 221 becomes the "0" level, and the comparator 222
The output is at the "0" level. That is,
Of the output terminals 23a to 23c of the decoder 23, 2
Only flip-flop circuit 3b is in the "1" level state, flip-flop circuits 241 and 242 are reset and set, their Q output and Q output are at "1" level, and AND gates 264 and 26
2 is entered.

When the steering wheel is rotated clockwise to start right steering from such a state, the steering rotation angle increases in the positive direction, and the analog voltage signal sent from the steering sensor 1 starts to gradually rise. Then, when the steering rotation angle exceeds +60°, the voltage value of the analog voltage signal exceeds V1, and the output of the comparator 222 changes from the "1" level to "0".
level (point a in Figure 2c).
That is, the outputs of comparators 221 and 222 both become "0" level, and the output of decoder 23 becomes "1".
The output terminal position that sends out the level is 23b from 23b.
Move up to a. As a result, the flip-flop circuit 241 enters the set state, and a signal of the "1" level is input to the multivibrator 253, and the multivibrator 253 transmits the one-shot signal of the "1" level to the AND gate 262 and the two.
65. On the other hand, flip-flop circuit 2
42 maintains the Q output at the "1" level even after the "1" level signal to the set terminal disappears,
As a result, both inputs of the AND gate 262 become "1" level, so the AND gate 262 begins to send out an output of "1" level. Therefore,
The output of the OR gate 271 becomes "1" level,
The count value in the up/down counter 27 increases by one. As a result, the decoder 28
The "0" level signal that was being sent out up to that point is increased and sent from the output terminal 28e to the output terminal 28d, and this "0" level signal is inverted by the inverter 291 and sent to the processing circuit 2 output terminal 2a. becomes level “1” (a in Figure 2 d)
point), the irradiation direction of the right lamp moves to the right.

If the right steering is continued even after reaching this state, the analog voltage signal sent by the steering sensor 1 will further increase, and at point b in Fig. 2a, where the steering rotation angle becomes +180 degrees,
The voltage value is leveled down from the maximum voltage value to the minimum voltage value. As a result, the comparator 221
The output of the comparator 222 is inverted from the "0" level to the "1" level (point b in FIG. 2b), and the output of the comparator 222 is also inverted from the "0" level to the "1" level (point b in FIG. 2c). point b). Therefore, the output terminal position of the decoder 23 that sends out the "1" level moves down from 23a to 23c, the flip-flop circuit 243 is set, and the multivibrator 251 sends the "1" level one shot signal to the AND gate 261. and start sending to 264. On the other hand, the flip-flop circuit 241 maintains the Q output of the "1" level even after the "1" level signal to its set terminal disappears, so the AND gate 261 sends out the "1" level output and the OR gate The output of 267 goes to the "1" level, and the count value in up/down counter 27 further increases by 1. As a result, the decoder 28 moves up the "0" level signal that had been sent out from the output terminal 28d to the output terminal 28c and sends it out. Then, when the steering rotation angle reaches +300° (point c in Figure 2 a), the outputs of comparators 221 and 222 become "0" and "1".
level (point c in Figure 2 b and c),
The output terminal 23b of the decoder 23 begins to send out a "1" level signal again, and the AND gate 2
The output of 63 becomes "1" level, and the count value in up/down counter 27 further increases. In other words, if you continue steering to the right starting from the straight steering position, the AND gates 262, 261,
The outputs of 263 become "1" level one by one, and the count value of up/down counter 27 becomes 1.
The output terminal positions for outputting the "0" level of the decoder 28 are 28d, 28c...28.
It will be carried forward sequentially with a. Here, like the output terminal 28d, the output terminals 28c to 28a are connected to the output terminal 2a via the inverter 291, so when the steering rotation angle exceeds +60°, the output terminal 28d of the decoder 28 is at the "1" level. After that, the level of the output terminal 2a remains at the "1" level, and the irradiation direction of the right lamp remains fixed at one point in the steering direction of the steering wheel.

On the other hand, when steering to the right starting from the above-mentioned straight steering position, the output terminal 28f of the decoder 28
~28i is at the "1" level, so the processing circuit 2
The level of the output terminal 2b (Fig. 2e) continues to maintain the "0" level, and the direction of irradiation of the left lamp does not change and continues to face forward. In other words, when steering to the right from the straight-ahead steering position, only the irradiation direction of the right lamp moves in conjunction with steering wheel steering to a predetermined deflection angle position on the steering direction side and is fixed, and this irradiation direction cannot be changed. This action ensures visibility when cornering by steering to the right. At this time, the left lamp illuminates the front direction in a fixed manner, ensuring visibility ahead of the vehicle and allowing safer cornering to the right.

When steering to the left starting from the straight-ahead steering position, the outputs of comparators 221 and 222 are both at the "1" level at point e in FIG. 2a (points e in FIGS. 2b and c), The output terminal position of the decoder 23 that sends out the "1" level moves down from 23b to 23c, the output of the AND gate 264 becomes the "1" level, and the count value in the up/down counter 27 becomes 1.
Just go down. As a result, the output terminal position of the decoder 28 that sends out the "0" level moves down from 28e to 28f, and the output terminal 2 of the processing circuit 2
b becomes level “1” (e in Figure 2 e)
point), the irradiation direction of the left lamp moves to the left.

If the left steering is continued even after reaching this state, the analog voltage signal sent by the steering sensor 1 will further decrease, and at point f in Fig. 2a, where the steering rotation angle becomes -180 degrees,
The voltage value increases from the minimum voltage value to the maximum voltage value. At this time, the outputs of comparators 221 and 222 both become "0" level (second
point f in Figures b and c), the output terminal position for sending out the "1" level of the decoder 23 is from 23c to 23a.
, the output of the AND gate 265 becomes "1" level, the count value in the up/down counter 27 decreases, and the output of the decoder 2
The output terminal position that sends out the “0” level of 8 is 28.
Move down from f to 28g. However, Fig. 2a
At point g in FIG. 2, the outputs of comparators 221 and 222 become "0" and "1" levels (points g in FIG. Therefore, the output terminal position for sending out the "1" level of the decoder 23 is from 23a to 23.
b, 23b to 23c, the outputs of the AND gates 266, 264 become "1" level, and the count value in the up/down counter 27 is further decreased. As a result, the output terminal position for sending out the "0" level of the decoder 28 is set to 2.
It is carried down sequentially from 8g to 28h and from 28h to 28i. Here, like the output terminal 28f, the output terminals 28g to 28i are connected to the output terminal 2b via the inverter 292, so when the steering rotation angle exceeds -60°, the output terminal 28f of the decoder 28 becomes "1". After reaching the level, the level of the output terminal 2b maintains the "1" level, and the irradiation direction of the left lamp remains fixed at one point in the steering direction of the steering wheel.

On the other hand, when steering to the left starting from the straight-ahead steering position described above, the output terminal 28a of the decoder 28
~28d is at the "1" level, so the processing circuit 2
The output terminal 2a continues to maintain the "0" level, and the irradiation direction of the right lamp does not change and continues to face forward. In other words, when steering to the left starting from the straight-ahead steering position, only the irradiation direction of the left lamp moves in conjunction with the steering wheel steering to a predetermined deflection angle position on the steering direction side and is fixed, and this irradiation direction cannot be changed. This action ensures visibility when cornering by steering to the left. At this time, the right lamp illuminates the front direction in a fixed manner, ensuring visibility to the front of the vehicle and allowing safer cornering to the left.

In this embodiment, the operation was explained when the steering wheel was rotated clockwise and counterclockwise from the straight-ahead steering position. However, while the output terminal positions of the decoder 28 at the "0" level are at 28a to 28d and 28f to 28i, the irradiation directions of the right lamp and left lamp do not change, and the irradiation is fixed in the right and left directions. Continue to maintain. And up/down counter 27
When the count value in the decoder 28 decreases, the count value in the decoder 28
When the output terminal 28e of the UP/DOWN counter 2 starts sending out a "0" level signal,
The count value at 7 goes up and decoder 2
At the point when the output terminal 28e of No. 8 begins to send out a signal of the "0" level, the irradiation direction of the right lamp or the left lamp is returned to the state facing the front and the lamp stops.

By the way, in a cornering lamp system that performs such basic operations, let us consider a case where the count value of the up/down counter 27 is in a state of deviation from the true count value. In other words, if the steering wheel is now in the straight steering position (rotation center position) and the car is traveling straight, the up/down counter 2
The count value at 7 should actually be zero. However, this count value may deviate from zero due to the reasons described above. This deviated count value is detected by the decoder 2.
8, a problem arises in that the possible irradiation direction operations of the right and left lamps controlled using this decoder 28 are shifted in accordance with the count value. However, in this embodiment, since the correction operation as described below is quickly performed, the irradiation directions of the right and left lamps can be varied in conjunction with the steering wheel steering without any problem.

In other words, as mentioned above, the rotation of the steering wheel in an automobile is usually 3 to 4 rotations in the lock-to-lock, and there are three origin positions within the rotatable range of the lock-to-lock (the predetermined rotational angular position of the steering wheel is rotationally opposite to the reference angular position). The output terminal 23b of the decoder 23 sends out a signal at the "1" level in a predetermined rotational angle range centered on the "position". In other words, the rotation angle range of ±60° of the steering wheel starting from the straight steering position (origin position) and the rotation angle position of each rotation of the steering wheel to the right and left from the straight steering position (origin position) The output terminal 23b of the decoder 23 sends out a "1" level signal in a rotational angle range of ±60° centered at . The count value in the up/down counter 27 is set to be zero at the straight-ahead steering position, and as the steering wheel rotates to the right, the count value increases in the positive direction, and as the steering wheel rotates to the left, the count value increases in the positive direction. Accordingly, the count value increases in the negative direction. In other words, the count value at the origin position when the steering wheel is rotated one turn to the right is larger than the count value at the straight steering position.
The count value at the origin position when the steering wheel is rotated one turn to the left is smaller than the count value at the straight steering position. Now, assuming that the count value at the straight-ahead steering position is NO, the count value at the rightward origin position is NR, and the count value at the leftward origin position is NL, the relationship NL<N0<NR is established. This relationship does not change even if there is a deviation in the count value of the up/down counter 27. That is, the order of the count values at the straight-ahead steering position is always located at the center of the count values at the rightward and leftward origin positions. Therefore, among the three origin positions of the steering wheel including the straight steering position, the origin position where the order of the count value in the up/down counter 27 is in the middle is determined to be the straight steering position (rotation center position) of the steering wheel. be able to.

Now, the car is running straight, and the steering sensor 1 detects V0 at point N in Figure 2 a.
Assume that an analog voltage signal with a voltage value of At this time, up/down counter 2
If there is no deviation in the operation at step 7, the count value will be zero. Therefore, decoder 2
9 sets its output terminal 29h to "1" level, and sets its output terminals 29e and 29k to "1" level at the right and left direction origin positions of the steering wheel.
shall be. However, if there is a deviation in the count value of the up/down counter 27,
Output terminal 2 of decoder 29 in the straight-ahead steering position
9h does not become the "1" level. It is now assumed that there is a deviation in the operation of the up/down counter 27 and that the output terminal 29g of the decoder 29 is at the "1" level at the straight steering position. At this time, the level of the output terminal 29d is "1" at the rightward origin position of the handle, and the level of the output terminal 29j is "1" at the leftward origin position.
becomes. When the output terminal 29g reaches the "1" level in the straight steering position, the other end of the AND gate 30g receives a "1" level signal (hereinafter, this "1" level signal) via the output terminal 23b of the decoder 23. Since the output of the AND gate 30g goes to the "1" level, the flip-flop circuit 31f is set and its Q output goes to the "1" level, which is input to the AND gate 321. The "1" level Q output sent by the flip-flop circuit 31f continues to be output even if the "1" level input to its set terminal disappears. Then, at the origin position in the right direction of the steering wheel, the output terminal 2 of the decoder 29
When 9d becomes "1" level, AND gate 30
The output of the flip-flop circuit 31d becomes "1" level, and the Q output of the flip-flop circuit 31d becomes "1" level.
It is input to AND gate 321. Therefore, at the leftward origin position, the output terminal 2 of the decoder 29
When 9j reaches the "1" level, the Q output of the flip-flop circuit 31h becomes "1" level,
All the inputs of the AND gate 321 become "1" level, and the gate of the AND gate 30r is opened. Therefore, after the output of the AND gate 321 becomes "1" level, at the straight steering position where the level of the output terminal 29g of the decoder 29 becomes "1" level, the two inputs of the AND gate 30r both become "1". The OR gate 33 sends out a signal at the "1" level, and a one shot signal at the "1" level is input to the reset terminal of the up/down counter 27 via the multivibrator 254. As a result, the count value in the up/down counter 27 is forcibly returned to zero, and the decoders 28 and 29
Let the levels of e and 29h be "0" and "1" levels.

That is, the origin position signal is sent out when the origin position is detected to be within the rotation angle range of ±60° centered on the origin position, and from among the three origin positions to which this origin position signal is sent, The origin position where the comparison order of the count values in the up/down counter 27 is in the center is selected, and the count value in the up/down counter 27 is corrected using this origin position as the true straight steering position. The lamp now performs normal irradiation direction variable operation in conjunction with the steering wheel. Then, at the falling edge of the one shot signal sent out by the multivibrator 254, the multivibrator 255 sends out a one shot signal of "1" level, and the flip-flop circuit 31d,
31f and 31h are returned to the reset state.

Also, at the rightward origin position of the handle, the output terminals 29a, 29b or 2 of the decoder 29
When 9c reaches the "1" level, the output terminals 29d,
29e or 29f is always at the "1" level at the straight-ahead steering position, and the up/down counter 27 makes corrections without checking the output state of the decoder 29 at the leftward origin position. That is, when the output level of the output terminal 29a of the decoder 29 becomes "1" at the rightward origin position of the steering wheel, the Q output of the flip-flop circuit 31a becomes "1" level and is inputted to one end of the AND gate 30p. When the output terminal 29a is at the "1" level at the rightward origin position, the output terminal 29a is always at the "1" level at the straight steering position.
When the level of d becomes "1" and the output terminal 29d becomes "1" level, the AND gate 30p
Both of the two inputs become the "1" level, the output of the OR gate 33 becomes the "1" level, and the count value in the up/down counter 27 is corrected. Similarly, when the output terminals 29b and 29c are at the "1" level at the rightward origin position, the output terminals 29e and 29f are at the "1" level at the straight-ahead steering position, and the AND gate 30e is at this straight-ahead steering position. and 3
The output of 0q becomes the "1" level, and the count value in the up/down counter 27 is corrected.

In addition, at the leftward origin position of the steering wheel, the output terminals 29o, 29n or 29 of the decoder 29
When m reaches the "1" level, the output terminals 291, 2
9k or 29j is always at the "1" level at its straight steering position, and there is no need to ensure the output state of the decoder 29 at the rightward origin position.
7 is performed. Also, the output terminals 291, 29i, 29f are set to "1" at each origin position.
level, the output of the AND gate 322 becomes the "1" level, and at the point when the output terminal 29i starts sending out a signal of the "1" level, the output of the AND gate 30s becomes the "1" level, and the output of the AND gate 30s becomes the "1" level, and the /The count value in the down counter 27 is corrected.

As explained above, according to the cornering lamp system according to the present embodiment, it is possible to reliably detect the straight steering position in a short period of time, and to
It is possible to accurately correct the irradiation direction variable operation in a transient driving mode in which the steering wheel is rotated widely at low speeds such as when changing direction or moving to the side, or in special driving modes such as on a mountain road with a series of tight corners.

In this example, the rotation of the steering wheel in the automobile is 3 to 4 rotations by lock-to-lock.
In this case, the steering wheel is located at three origin positions including the straight steering position within the rotatable range of the steering wheel lock, but it can also be applied to steering wheel steering with a wider rotatable range, in which case the steering wheel is in the straight steering position. It goes without saying that the minimum requirement is to locate the site at an odd number of different origin positions. Further, in this example, the steering sensor 1 is configured to send an analog voltage signal in conjunction with steering wheel steering, but the sensor output is not limited to an analog voltage signal, and the processing is based on the digital sensor output. It goes without saying that it is also possible to do this.

Furthermore, although this embodiment has described a cornering lamp system for a vehicle, it is not limited to such a cornering lamp system, and various controls can be performed based on the determined straight steering position, and its utility value is Extremely high.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, when all of the odd number of different origin positions located in the rotatable range are detected, the origin position of the center order is used for straight-line steering of the vehicle. The position can be accurately determined in a short time, and the count value in the up-down counter can be corrected at the time of determining the straight steering position.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram in which an embodiment of the straight-ahead steering position determination method according to the present invention is applied to a cornering lamp system in a vehicle, and FIG. 2 is a time chart illustrating the operation of this cornering lamp system. 1...Steering sensor, 2...Processing circuit,
27... Up/down counter, 23, 28,
29...Decoder, 30a-30u...AND gate, 31a-311...R.S flip-flop circuit, 321, 322...3-input AND gate.

Claims (1)

[Scope of Claims] 1. Rotates clockwise and counterclockwise in conjunction with steering wheel steering in a vehicle, and has a predetermined rotational angular position rotationally opposite to a reference angular position as the origin position, and within its rotatable range. A rotating body located at an odd number of different origin positions, an origin position detection means for detecting the origin position located every rotation of the rotating body, and an increase in the rotation angle of the rotating body in the clockwise and counterclockwise directions. counter means that increases and decreases the count value in accordance with the rotation of the rotating body, and after detecting all the origin positions in the rotatable range of the rotary body, the comparison order of the count values in the counter means is the origin point where the comparison order of the count value becomes the center order. A method for determining a straight steering position in a vehicle, characterized in that the position is determined as a straight steering position of the steering wheel.