JPH0577962B2 - - 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, the straight steering position (N in Fig. 2a)
When the steering wheel is rotated clockwise from point ), the steering rotation angle increases from 0° in the positive direction as shown in the figure, and as the rotation angle increases, the sensor output gradually increases. 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 sensor outputs that raise and lower the comparison reference voltages V1 and V2. That is, the sensor output gradually increases beyond the comparison reference voltage V1, the sensor output suddenly falls from the maximum voltage value _Vnax to the minimum voltage value _Vnio , and the sensor output gradually increases beyond the comparison reference voltage V2. , the clockwise rotation and position of the handle can be detected, 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. Also, the comparison reference voltage V2
The sensor output gradually decreases when the voltage drops below V1, the sensor output suddenly rises from the minimum voltage value V _nio to the maximum voltage V _nax , and the sensor output gradually decreases after falling below the comparison reference voltage V1. You can know the rotation and position in the direction,
At the time of transition to each mode, a down signal is sent out to decrease the count value in the up/down counter.

[Problem that the invention seeks to solve]

However, according to such a conventional method of detecting the rotational direction and position of the handle, when the up-down counter miscounts, there is no means to correct the error in the count value, and the error accumulates. 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, and the present invention has been made in such a manner that a predetermined rotational angular position of a rotating body that rotates clockwise and counterclockwise in conjunction with steering wheel steering in a vehicle is a position rotationally opposite to a reference angular position. The origin position is set as the origin position, and an analog signal that rises and falls around a predetermined reference value is sent out in conjunction with clockwise and counterclockwise rotational movements about the origin position, which is located every rotation of the rotating body. From this analog signal value, the origin position located every rotation of the rotary body is detected, and after the origin position is detected, a predetermined position is detected from among the origin positions positioned every one rotation of the rotary body. The origin position where no other origin position can be detected until the time elapses is
This is determined as the straight steering position of the steering wheel.

[Effect]

Therefore, according to the present invention, among the origin positions located every rotation of the rotating body, the origin position where no other origin position can be detected within a predetermined period of time after detection of the origin position is detected by the vehicle. It can be defined as the straight-ahead steering position of the steering wheel.

〔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-ahead steering position determination method according to the present invention, and is an example applied 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 22 in processing circuit 2
2,223 inverting input terminal and comparator 2
The comparison reference voltage V2 determined by resistors R1 and R2 and the comparison reference voltage determined by resistors R3 and R4 are input to the non-inverting input terminals of comparators 221, 222, and 223. A comparison reference voltage V3 determined by V1 and resistors R5 and R6 is set. Also,
A resistor R is connected to the inverting input terminal of the comparator 224.
7, a comparison reference voltage V4 determined by R8 is set. In this embodiment, the comparison reference voltage V
1 is set higher than the voltage value V0 of the analog voltage signal generated in the straight-ahead steering position by +60 degrees in terms of steering rotation angle, and the comparison reference voltage V2 is set lower than V0 by -60 degrees in terms of steering rotation angle. The comparison reference voltage V3 is set higher than V0 by +15 degrees in terms of steering rotation angle, and the comparison reference voltage V4 is set higher than V0 by -15 degrees in terms of steering rotation angle. Then, the outputs of comparators 221 and 222 are
3, and the decoder 23 receives the input from the input terminals 23A and 23B.
When "0" level signals are input to both A and 23B, the level of the output terminal 23a is set to "1" level, and when "0" and "1" level signals are input to both, the output terminal 23b is set to the "1" level. The level of the output terminal 23c is set to the "1" level, and when both signals of the "1" level are input, the level of the output terminal 23c is set to the "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 fixed period of time, and the AND gates 263 and 266
A one-shot signal of level "1" is sent to one end of the terminal. Furthermore, the output terminal 23c of the decoder 23 is connected to the R/S flip-flop circuit 2.
When the output terminal 23c reaches the "1" level, the one-shot multivibrator 251 continues for a predetermined period of time, and one end of the AND gates 261 and 264 is connected. A one-shot signal of level "1" is sent to the terminal.

On the other hand, the Q output and output of flip-flop circuit 241 are input to the other ends of AND gates 26 and 264, and the Q output and output of flip-flop circuit 242 are input to the other ends of AND gates 262 and 265. The Q output and output of circuit 243 are input to the other ends of AND gates 263 and 266. And gate 261-2
63 and the outputs of AND gates 264 to 266 are input to each input terminal of three-input OR gates 271 and 272. The outputs of the OR gates 271 and 272 are then applied to the up input terminal 27u of the first up/down counter 27.
and down input terminal 27d, up input terminal 30u and down input terminal 30d of the second up/down counter 30, and up/down counters 27 and 30 have input terminals 27u and 30u or 27d.
Each time a "1" level signal is input to 30d, the count value is increased or decreased. The first up/down counter 27 sends a digital signal corresponding to the count value to the decoder 28, and the decoder 28 receives this digital signal and outputs one of its output terminals 28a to 28i. A predetermined output terminal is selected and its level is set to "0" level. That is, the count value in the up/down counter 27 is set to zero at point N in FIG. It is set to the "0" level. And atup/
Each time the count value of the down counter 27 increases by one, the output terminal to be set to the "0" level is incremented sequentially from 28e to 28d, 28c, . . . 28a. Further, each time the count value in the up/down counter 27 decreases by one from zero, the output terminal to be set to the "0" level is incremented sequentially from 28e to 28f, 28g, . . . 28i. It should be noted that even when the up/down counter 27 counts down after a count-up or counts up after a count-down, the output terminals that reach the "0" level are successively incremented or incremented to the adjacent output terminals. No need to say. The output terminals 28a to 28d of the decoder 28 are connected to the output terminal 2a of the main processing circuit 2 via an inverter 291, and the output terminals 28f to 28i are connected to the output terminal 2b via an inverter 292. When the output terminals 2a and 2b reach the "1" level, the headlight (not shown) installed on the right side of the front of the vehicle (hereinafter referred to as the right lamp) and the front headlight (not shown) installed on the left side of the front of the vehicle are activated. The irradiation direction of the illumination light (hereinafter referred to as the left lamp) is configured to rotate to the right and left.

The reset terminal of the second up/down counter 30 has a “1” passed through the AND gate 266.
A level origin position detection signal is inputted, and the up/down counter 30 returns its count value to zero when this origin position detection signal is inputted. That is, the voltage value of the analog voltage signal sent by the steering sensor 1 is V at the rotation angle position (origin position) for each rotation of the steering wheel starting from the straight steering position.
0, and within the comparison reference voltage value range of V4 to V3 including this V0 (within the rotation angle range of ±15 degrees), the output levels of the comparators 223 and 224 both become the "1" level. In other words, when the outputs of comparators 223 and 224 both reach the "1" level, the AND gate 266
The "1" level signal input to is used as the origin position detection signal. The output of the R.S. flip-flop circuit 244 is input to the other end of the AND gate 266, and the output of the AND gate 266 is input to the set terminal of the flip-flop circuit 244.
The Q output of 4 is input to one end of an AND gate 267 and an AND gate 268. The clock signal sent from the reference clock generator 32 is input to the other end of the AND gate 268, and the origin position detection signal input to the AND gate 266 is branched to the other end of the AND gate 267. It is now possible to input The output of the AND gate 267 is input to the enable terminal of the comparator 31, and when a signal of level "1" is input to the enable terminal, the comparator 31 changes the current value of the up/down counter 30. The count value is taken in, and the comparison reference value setting terminals 31a to 3 are
Reference comparison count value N0 set via 1d
= 0, and when the captured count value does not match the reference comparison count value N0, a reset signal of level "1" is sent to the frequency divider 33. A clock signal passing through an AND gate 268 is input to the frequency divider 33, and every time this clock signal is input for 30 seconds or more, it overflows and the up/down counter 27 is 1" level load signal is sent out. When this load signal is input, the up/down counter 27 takes in the count value of the up/down counter 30 at that time and rewrites the count value. That is, the count value in the up/down counter 30 is transferred to the up/down counter 27, and the count value in the up/down counter 30 is transferred to the up/down counter 27.
The count value in the down counter 27 is rewritten with this transferred count. The reset signal sent by the comparator 31 and the load signal sent by the frequency divider 33 are branched and input to an OR gate 273, and the output of the OR gate 273 is input to the reset terminal of the flip-flop circuit 244. It's becoming like that.

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 "1" 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 output and Q output are at "1" level, and AND gates 264 and 262 are in the "1" level state.
has been 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 is inverted from the "1" level to the "0" level (point a in Figure 2 c). ). That is, the outputs of the comparators 221 and 222 both become "0" level, and the output terminal position of the decoder 23 that sends out the "1" level is shifted from 23b to 23a.
It goes up to . 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 of the two inputs of the AND gate 262 become "1" level, so the ungate 262 starts sending out an output of "1" level. Therefore,
The output of the OR gate 271 goes to the "1" level, and the count value in the up/down counter 27 goes up by one. As a result, the "0" level signal that the decoder 28 had been sending out until then is incremented and sent from the output terminal 28e to the output terminal 28d, and this "0" level signal is inverted by the inverter 291 and processed. circuit 2
The output terminal 2a of is at the "1" level (Fig. 2d)
point a), 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 a one-shot signal of "1" level to the AND gates 261 and 2.
Start sending to 64. 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 267 output is “1”
level, and the count value in the up/down counter 27 further increases by one. 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 Fig. 2a), the outputs of comparators 221 and 222 become "0" and "1" levels (points c in Fig. 2b and c), and the decoder The output/output terminal 23b of 23 begins to send out a signal at the "1" level again, the output of the AND gate 263 becomes "1" level, and the count value in the 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, 263
The outputs of the decoder 28 sequentially become "1" level, the count value in the up/down counter 27 goes up by 1, and the output terminal position of the decoder 28 that sends out the "0" level is incremented sequentially to 28d, 28c, . . . 28a. become. Here, the output terminal 28c
28a is connected to the output terminal 2a via the inverter 291 like the output terminal 28d, so after the Stelling rotation angle exceeds +60° and the output terminal 28d of the decoder 28 becomes the "1" level, The level of the output terminal 2a is maintained at the "1" level, and the irradiation direction of the right lamp remains fixed at one point in the steering direction. On the other hand, during right steering starting from the above-mentioned straight steering position, Output terminal 28f of 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 in front 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 to 23b or 23c, the output of the AND gate 264 becomes the "1" level, and the count value in the up/down counter 27 becomes 1.
It goes down only once. 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 the “1” level (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 23a or 23.
b, 23b to 23c, the outputs of AND gates 266, 264 become "1" level, and the count value in 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. Even if the output terminal position of the decoder 28 becomes "0" level is 28a to 28d, 28f to 2
While at 8i, the irradiation directions of the right lamp and the left lamp do not change and continue to maintain fixed irradiation in the right and left directions. Then, when the count value in the up/down counter 27 goes down and the output terminal 28e of the decoder 28 starts to send out a "0" level signal, or when the count value in the up/down counter 27 goes up and the decoder At the point when the output terminal 28e of 28 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 stopped.

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 deviated 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 count value in the up/down counter 27 should actually be zero. be. However, this count value may deviate from zero due to the reasons described above. If such a deviated count value is input to the decoder 28, a problem arises in that the irradiation direction variable operation of the right and left lamps, which is controlled using the decoder 28, is deviated 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, it is no exaggeration to say that most of the roads that cars travel on are straight roads, and cars do not drive for long periods of time with the steering wheel turned once. In other words, the voltage value of the analog voltage signal sent by the steering sensor 1 is the comparison reference voltage V4 to V3 at the rotation angle position (origin position) of each clockwise and counterclockwise rotation of the steering wheel starting from the straight steering position. Even if the vehicle stays within the range of V4 to V3, the staying time is short, and after traveling for a short time, it comes to stay within the range of V4 to V3 at the straight steering position (origin position). In the inventor's research based on an actual vehicle, although the steering wheel may be rotated once while driving on a U-turn road, etc., it took less than 30 seconds to return the steering wheel to the straight-ahead steering position. In other words, a rotation angle range of ±15° (right and left direction After the origin position detection signal is input to AND gates 266 and 267, it is assumed that entering this rotation angle range has detected the origin position. In the rotation angle range of ±15° (near the straight steering position), the origin position detection signal is input to AND gates 266 and 267, assuming that the origin position has been detected when the rotation angle range is within this rotation angle range. Therefore, if no origin position detection signal is generated in the vicinity of another origin position before 30 seconds have elapsed, there is no problem in determining that the current origin position is the straight-ahead steering position.

It is now assumed that the flip-flop circuit 244 and the frequency divider 33 are in the initial reset state, and the outputs of the comparators 223 and 224 are both at the "1" level in the straight-ahead steering position. At this time, the origin position detection signal at the "1" level is input to the AND gates 266 and 267.
Since the "1" level output of the flip-flop circuit 244 is input to the other end of the AND gate 266, the origin position detection signal input to one end thereof passes through the AND gate 266 and resets the up/down counter 30. At the same time, the flip-flop circuit 244 is set. As a result, the count value in the up/down counter 30 becomes zero, and the flip-flop circuit 244
sets its Q output and output levels to "1" and "0" levels. Flip-flop circuit 2
When the output of 44 is inverted to the "0" level, the gate of AND gate 266 is closed, but when the Q output thereof is inverted to the "1" level, the gates of AND gates 267 and 268 are opened. Therefore, the clock signal sent from the reference clock generator 32 passes through the AND gate 268 and begins to be input to the frequency divider 33.
The origin position detection signal passes through 67. The comparator 31 is activated by the origin position detection signal passing through the AND gate 267, takes in the current count value of the up/down counter 30, and compares it with the reference comparison count value N0. At this time,
Since the count value of the up/down counter 30 has already become zero due to the origin position detection signal inputted through the AND gate 266, it matches the reference comparison count value N0=0. Therefore,
The comparator 31 does not send a "1" level reset signal to the frequency divider 33, and the frequency divider 33 continues to divide the frequency of the input clock signal. This frequency dividing operation in the frequency divider 33 continues not only during the period when the origin position detection signal is generated near the straight-ahead steering position, but also during the period when the origin position detection signal is no longer generated. In other words, in general, even when a car is traveling straight ahead, it actually performs fine steering, and therefore, steering wheel steering that exceeds ±15 degrees around the straight ahead steering position may generate an origin position detection signal. It doesn't occur and it gets wet. If the origin position detection signal is generated,
As a result of the comparison operation performed in the comparator 31 as described above, the frequency division operation in the frequency divider 33 is not reset. When the origin position detection signal is no longer generated, the comparison operation itself in the comparator 31 is not performed, so no reset signal is sent to the frequency divider 33.
In other words, once the origin position detection signal is generated near the straight steering position, the frequency dividing operation in the frequency divider 33 continues even if the origin position detection signal is no longer generated. in
After 30 seconds have elapsed, an overflow of the clock signal input to the frequency divider 33 occurs, and a load signal is sent to the up/down counter 27. The up/down counter 27 receives this load signal, takes in the current count value of the up/down counter 30, and rewrites the count value. That is, if the steering wheel is in the straight steering position at this point, the count value in the up/down counter 30 is zero, and this count value is transferred, and the count value in the up/down counter 27 becomes zero. Also, at this time, if the steering wheel is not in the straight steering position and is rotating (within ±345°), the up/down counter 30 is performing an accurate count starting from the straight steering position. Value goes up/down counter 2
It will be forwarded to 7. In other words, even if the up/down counter 27 makes a miscount, the accurate count value of the up/down counter 30 is taken into the up/down counter 27, and appropriate correction is performed. In addition, frequency divider 3
The load signal sent out by the flip-flop circuit 244 is also input to the reset terminal of the flip-flop circuit 244 via the OR gate 273.
4 to the reset state, and prepare for the input of the next origin position detection signal.

By the way, the above operation has been explained with respect to the operation after the origin position detection signal is generated near the straight-ahead steering position, but while the car is running, the origin position detection signal is also generated at the steering position at every rotation as described above. . Now flip-flop circuit 2
44 and frequency divider 33 are in the initial reset state, and the origin position detection signal is generated at one rotation steering position. The origin position detection signal at the "1" level is input to the AND gates 266 and 267 in the same manner as described above, and the count value in the up/down counter 30 becomes zero, and
The clock signal sent from the reference clock generator 32 begins to be input to the frequency divider 33. At this time, the comparator 31 takes in the count value of the up/down counter 30 and compares it with the reference comparison count value N0, but since the count value of the up/down counter 30 has already reached zero at this point, the reference comparison count value Since N0=0, the frequency divider 33 continues to perform its frequency dividing operation without being reset. However, as described above, the time required to return the steering wheel from the one-turn steering position to near the straight-ahead steering position is less than 30 seconds. Therefore, the origin position detection signal generated at the straight-ahead steering position will be input to the AND gate 267 within 30 seconds, and the comparator 31 will again detect the origin position by inputting this origin position detection signal to the enable terminal. A comparison operation will now be performed. At this time, comparator 3
The count value of the up/down counter 30 taken into 1 is 1 with the 1 rotation steering position as the zero reference.
This is a count value for rotations, and does not match the reference comparison count value N0. Therefore, the comparator 31 sends out a reset signal of "1" level at this point, and the frequency divider 33 is reset. here,
The timing of the reset signal input to the frequency divider 33 is within 30 seconds after the clock signal starts being input to the frequency divider 33. Therefore, the frequency divider 33
is reset without waiting for the overflow of the clock signal, and no load signal is sent to the up/down counter 27. In other words, the count value in the up/down counter 30 at this time is the count value when the position of one rotation of the steering wheel in the right or left direction is determined as the temporary straight steering position, and using this count value, the up/down counter 27 No correction is made to the count value in . Then, the reset signal sent from the comparator 31 is inputted to the reset terminal of the flip-flop circuit 244 via the OR gate 273, and this flip-flop circuit 244 is set in a reset state in preparation for inputting the next origin position detection signal.

As explained above, according to the cornering lamp system according to the present embodiment, the up/down counter 30 performs counting with each origin position set as a temporary straight-ahead steering position, but the count is transferred to the up/down counter 27. The count value only corresponds to the true straight-ahead steering position, and accurate and appropriate corrections are made using this count value, making it possible to change the illumination direction of the right and left lamps without any problems in conjunction with steering wheel steering. can. In addition, once the origin position detection signal is generated near the straight-ahead steering position, even if the steering wheel is subsequently steered (within ±345°), the up/down counter 2
The correction in step 7 is performed accurately, and even when the vehicle is traveling on a curve, the correction of the variable irradiation direction operation of the right and left lamps is reliably performed.

In this embodiment, the frequency division ratio of the frequency divider 33 is set to 30 seconds in terms of time, but it is not necessarily limited to 30 seconds, and the time is not limited to 30 seconds. It goes without saying that any value may be set as long as it is longer than the time required to reliably return to . Furthermore, in this example,
Although the origin position detection signal is generated within a rotation angle range of ±15° with the origin position as the center, it goes without saying that this is not necessarily limited to ±15°.

Furthermore, although this embodiment has described the correction operation of the counter in a cornering lamp system, it goes without saying that the correction operation is not limited to such a cornering lamp system.
A counter in another system whose movement is controlled in conjunction with steering wheel steering may be corrected. Further, the present invention is not limited to such counter correction, 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 description, according to the present invention, among the origin positions that are located for each revolution of the rotating body, other origin positions can be detected until a predetermined time elapses after the origin position is detected. The origin position is determined as the straight steering position of the steering wheel in the vehicle,
At the time of determining this straight-ahead steering position, it becomes possible to correct the miss count in the up-down counter.

[Brief explanation of drawings]

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,
221-224... comparator, 27... first
up/down counter, 28...decoder, 241-244...R/S flip-flop circuit, 30...second up/down counter,
31... Comparator, 32... Reference clock generator, 33... Frequency divider.

Claims (1)

[Scope of Claims] 1. A rotating body that rotates clockwise and counterclockwise in conjunction with steering wheel steering in a vehicle, and a position where a predetermined rotational angular position of this rotating body rotationally opposes a reference angular position is defined as an origin position, In conjunction with the rotational movement in the clockwise and counterclockwise directions around the origin position located every rotation of this rotating body,
an analog signal sending means for sending out an analog signal that rises and falls around a predetermined reference value; and an origin position for detecting an origin position for each rotation of the rotating body from the analog signal value sent by the analog signal sending means. of the origin positions that are located every rotation of the rotating body, the origin position where no other origin position can be detected within a predetermined period of time after the detection of the origin position is detected by detecting the origin position of the handle. A method for determining a straight-ahead steering position in a vehicle, characterized in that the determination is made as a straight-ahead steering position.