JP2594487B2 - Reflector detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring the distance between a host vehicle and a preceding object and issuing an alarm when the distance becomes smaller than a safe inter-vehicle distance. The present invention relates to a reflector detecting device that does not issue an alarm when an arrayed reflector is detected as a forward object.

[0002]

2. Description of the Related Art Conventionally, a device for confirming a safe inter-vehicle distance is widely known. This device emits ultrasonic waves and laser light from the front of the car and reflects it on the object in front,
The distance between the host vehicle and the object in front is measured from the time from when the reflected light is received and emitted to when it is received, and an alarm is issued when the measured distance becomes smaller than a predetermined safe inter-vehicle distance. It is configured as follows. When a vehicle equipped with such a device approaches a curve while traveling, a warning is issued by a roadside reflector. The roadside reflectors are arranged at predetermined intervals on a roadside outside a sharply curved road, and reflect light from a headlight to notify a driver that the road is sharply curved.

[0003] When a vehicle equipped with the safety inter-vehicle distance checking device as described above is approaching a sharp curve, even if the driver operates the steering wheel along the curve and travels normally, the distance between the vehicle and the roadside reflector is reduced. Is less than the safe inter-vehicle distance, an alarm is issued. This warning can be very annoying because it will be issued all the time while you are on the curve. In order to solve such a problem, for example, Japanese Unexamined Patent Publication No.
-130500 discloses a collision warning device and the like. However, such a collision warning device also has various problems.

FIG. 6 is a diagram showing a state of detecting a roadside reflector while the vehicle is traveling on a curve, and FIG. 7 shows a waveform of the detection signal. 1 is an automobile, 2 is a sharply curved road, 3 is a plurality of shoulder reflectors arranged at predetermined intervals along the outer shoulder of the road 2, and 4 is a transmitter (not shown) installed in front of the automobile. ) Is a beam of laser light or the like emitted from.

The light reflected by the roadside reflector 3 after receiving the beam 4 is received, and the distance between the vehicle 1 and the nearest roadside reflector 3 in front is detected from the time from transmission to reception. You. As shown by the dotted line in FIG. 6, when the roadside reflector 3a detected by running the automobile 1 goes out of the range of the beam 4, the distance to the next roadside reflector 3b is detected. This detection operation is continuously performed as the vehicle 1 travels, and a detection distance of a waveform that changes in a sawtooth shape as the vehicle travels as shown in FIG. 7 is obtained. This detection distance starts decreasing from the detection distance s where the sudden change occurred,
When the distance is reduced to the closest detection distance t, the roadside reflector 3
a goes out of the beam 4, the next roadside reflector 3b is detected, and the detection distance increases rapidly. Detection distance is safe inter-vehicle distance Dr
An alarm will be triggered when: An alarm sounds periodically each time the vehicle passes through the roadside reflector 3, which is very troublesome.

The above-mentioned collision warning device stores the detected distance s when it is detected, and detects the detected distance s by subtracting the distance i from the automobile 1 to the roadside reflector 3 which is sequentially detected from the detected distance s. The difference (s−i) is monitored, and if the value of the difference is smaller than a predetermined value corresponding to the distance between the road shoulder reflectors corresponding to (s−t), it is determined that the detected object is a stationary body. After that, the warning of the collision warning device is prohibited. That is, even if the detection distances st become equal to or less than the safe inter-vehicle distance, no alarm is issued immediately, and if the detection distance difference (si) is smaller than the set value, the detected object ahead is a stationary object and a road shoulder. Since it is determined that the object is the reflector 3 and the collision is not expected, it is not necessary to issue a warning, and the generation of the warning is prohibited. If the detected distance difference (s−i) is larger than the set value, an alarm is issued because the currently detected object is not a roadside reflector, and if the detected distance difference (s−i) is too small, It is dangerous because it is very close to the car 1, and the prohibition is released and an alarm is issued.

[0007]

However, in such a conventional apparatus, it is determined whether or not the detected object is a stationary object based on the relative speed as described above. Performs operations such as prohibition of alarms. When this operation is performed, more than a dozen distance data are required to obtain the relative speed, and it takes time to detect the relative speed. Therefore, there is a problem that the detection of the traveling distance and the prohibition of the warning are delayed.

[0008]

SUMMARY OF THE INVENTION The present invention detects a sudden increase in the detection distance after the detection distance can be measured by a signal from a means for measuring the traveling distance of the vehicle and a distance measurement means for measuring a distance to a forward object. Means for outputting a sudden increase signal when the vehicle travels, means for measuring the traveling distance of the vehicle from the point of sudden increase detection based on the sudden increase signal, and determining whether or not the traveling distance measured after the sudden increase has reached a predetermined set value. A means for outputting a set value excess signal when the set value is reached, and an alert action signal when the distance to the object is less than the safe inter-vehicle distance, and an alert action when the rapid increase signal is generated twice in succession. If a signal is generated, prohibit its generation, release the prohibition when a set value excess signal is generated, and a predetermined distance from the detection distance immediately before the sudden increase in the distance to the object when the detection distance suddenly increases. Reduced In which also provided an alarm control means for canceling the prohibition when it is away below.

[0009]

When a sudden increase in the detection distance is detected twice in succession, it is immediately determined that the vehicle is a roadside reflector, and the generation of an alarm signal is prohibited, so that the alarm does not continue to sound while traveling on a curve. If the object ahead is not a roadside reflector,
Even if the vehicle travels to the set value, the sudden increase in the next detection distance is not detected, and the prohibition of the alarm is released. The prohibition is also released when the distance becomes less than a distance obtained by subtracting a predetermined distance from the detection distance immediately before the sudden increase, because the forward object approaches and is dangerous.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to embodiments. FIG. 1 is a block circuit configuration diagram showing one embodiment of the present invention. In the figure, reference numeral 10 denotes a well-known distance measuring unit installed in front of a car, which measures a distance from a time until a laser beam is emitted and a reflected light is received to a forward object, and is approximately 100 m. The object ahead can be measured. If the object in front is farther away, or if it moves off to the left or right, measurement becomes impossible. 4 is a launch beam, 11 is a control means composed of a microcomputer, 12 is an alarm based on alarm information output from the control means 11 when the distance between the car and the distance measuring object becomes less than a predetermined safe inter-vehicle distance. The warning means 13 is a running detecting means for measuring the running distance of the automobile. The travel detecting means 13 outputs one pulse each time the vehicle travels a unit distance, and can measure the travel distance of the automobile by counting the number of pulses.

The control means 11 inputs a distance signal from the distance measuring means 10 and detects a sudden increase in the detected distance. The control means 11 outputs a sudden increase signal, and a sudden increase signal output from the sudden increase detection means 11a. And traveling detection means 13
And a mileage measured by the mileage measuring means 11b, which comprises a counter for measuring the mileage of the vehicle from the point of sudden increase detection, and a mileage measured by the mileage measuring means 11b after the sudden increase is set to a predetermined value. And the distance to the object measured by the distance measuring means 10 is equal to or less than the safe inter-vehicle distance. When an alarm operation signal for driving the alarm means 12 is generated,
If the alarm operation signal is generated when the sudden increase detection means 11a generates the rapid increase signal twice, the sudden increase signal becomes an alarm prohibition signal to inhibit the generation of the alarm operation signal, and the traveling distance determination means 11c And alarm control means 11d for performing control such as releasing the prohibition when a set value excess signal is generated.

FIG. 2 is a diagram showing the relationship between the traveling distance of the automobile and the detected distance measured by the distance measuring means 10. This figure is basically the same as FIG. When the vehicle approaches a curve, the detection distance can be measured from point p, and when the roadside reflector is detected, the detection distance decreases as the vehicle travels. When the detection distance becomes less than the safe inter-vehicle distance Dr, alarm control is performed. An alarm operation signal is output by the operation of the means 11d, and an alarm signal is generated from the alarm means 12. The B counter provided in the control means 11 starts counting from the measurable p point, and measures the traveling distance. After the car approaches the first shoulder reflector and the detection distance is further reduced,
At the point a, the next roadside reflector is detected and the sudden increase detecting means 11a
As a result, a sudden increase in the detection distance is detected.

When the detection distance suddenly increases at the point a, it is predicted that the detection will be performed by the roadside reflector, and the mileage measuring means 11b (A counter) after the rapid increase operates from this point a to measure the mileage of the automobile. I do. Then, before the traveling distance reaches the set value R which is set to be slightly larger than the arrangement distance in advance based on the arrangement distance of the roadside reflector, the sudden increase in the next detection distance is detected by the sudden increase detection means 11a at the point b. Then, the running distance measuring means 11b after the sudden increase operates again to newly measure the running distance of the vehicle from this point b. That is, after the A-counter indicating the running distance is reset once, the operation is restarted, and the running distance from the sharp increase point is counted. Due to the second increase in the detection distance, the alarm operation signal that has been generated until then is stopped by the operation of the alarm control unit 11d.

Thereafter, the same detection state continues while the vehicle is traveling on a curve, and a sudden increase in the detection distance is detected one after another before reaching the set value R at the point c or the like. The distance judging means 11c does not generate the set value excess signal, and therefore the prohibition of the alarm operation signal is not released by the operation of the alarm control means 11d. If the next detection distance does not suddenly increase even after traveling the set value R, it is assumed that the vehicle has passed the area of the roadside reflector, and the operation of the alarm control means 11d does not inhibit the generation of the alarm operation signal. An alarm signal is generated from the means 12. If the detected distance measured by the distance measuring means 10 at this time is equal to or longer than the safe inter-vehicle distance Dr, no alarm operation signal is generated.

Further, even when the detected distance does not travel the set value R, the prohibition of the alarm operation signal is released and the alarm operation signal is generated when the object ahead approaches too much. In FIG. 2, when a sudden increase occurs at the point c, the detected distance X immediately before the sudden increase is stored.
The distance obtained by subtracting m is calculated and stored. And d
If the detected distance at this point is less than or equal to this distance “X−20” m, the alarm control signal of the alarm control means 11d is actuated by the action of the alarm control means 11d in the same manner as when the vehicle travels at the set value R even if the vehicle does not travel to the set value R. The prohibition is not performed, the prohibition is released and the alarm means 1
2 generates an alarm signal. According to this embodiment, the structure is simplified because there is no conventional stationary object discriminating means, and the alarm is prohibited immediately when a sudden increase in the detection distance is detected. There is no need to do so, and the alarm prohibition operation becomes faster. Next, FIGS. 3 and 4
The operation of the control means 11 will be described in detail with reference to the flowchart of FIG.

In step 20, initialization is performed, and the A counter and the B counter for counting the traveling distance are set to 5 respectively.
1 m, the data α and β representing the detection distances are respectively set to 99 m corresponding to the maximum detection distance, the A flag is set to “0”, and the alarm prohibition flag is set to “0”. . Next, in step 21, is to measure the detection distance D _n is the distance between the automobile and the front distance measuring object, in step 22, the detection distance Dn
Is determined whether measurement is impossible. If it is measurable, in step 23, as to set a detection distance D _n is the current measurement values to alpha, it sets the previous alpha to beta. Initially, β is set to 99 m because there is no previous α.

Next, at step 24, it is determined whether or not the detection of the detected distance has started, that is, whether or not the distance measurement was previously impossible and the distance measurement is now possible. At first, since the distance measurement can be performed for the first time this time, the process proceeds to step 25, where 5
The B counter set at 1 m is reset to 0 m. Then, the process proceeds to the next step 26. If it is determined in step 24 that the distance measurement has been continued twice, the process directly proceeds to step 26 without passing through step 25. In this step 26, it is determined whether or not the difference between α, which is the current detection distance Dn, and β, which is the previous detection distance D _n-1 , is equal to or greater than a predetermined value (for example, 5 m). That is, it is determined whether or not the detection distance has suddenly increased.

The distance measurement of the forward object by the distance measuring means 10 is performed by periodically sampling data.
The sampling period is, for example, 36 milliseconds. Distance detection is performed every 0.1 millisecond, and the detection values of 10 times are averaged in hardware and taken in every 1 millisecond.
An average of six times is used as a sampling value of the detection distance. The above detection distances D _n-1 and Dn are respective sampling values.
At step 26, as shown at point a in FIG. 2, when it is determined that the initial detection distance has increased rapidly, at the same time, at step 27, the distance immediately before the increase is stored, and the previous detection distance D _n-1 is obtained. β is set as data X (the distance immediately before the rapid increase), and in the next step 28, “X−20” m is calculated, and this data is stored in the memory. The distance of 20 m is a distance arbitrarily set according to safety.

Next, at step 29, it is determined whether or not the second detection distance has increased rapidly. Since only one rapid increase has yet been detected at point a, it is determined to be "NO" and the A flag is set to "1" in step 30. Further, in step 32, the A counter is reset to 0m. Here, as shown at point b in FIG. 2, if it is determined that the detection distance has increased rapidly for the second time, “YES” is determined in step 29 and the process proceeds to step 31, where an alarm prohibition signal is generated. The alarm prohibition flag is set to "1". next,
At step 33, it is determined whether or not the alarm prohibition signal has been generated (whether or not the alarm prohibition flag is "1"). Since the alarm prohibition signal has already been generated at step 31, the process proceeds to step. .

In step 34, it is determined whether or not the running distance after the rapid increase in the distance, that is, the count value of the A counter generated after the rapid increase in the distance exceeds 50 m. Note that the distance of 50 m is a predetermined distance set to a value larger than the normal distance between the roadside reflectors. In step 34, while the running distance after resetting the counter does not reach 50 m, the flow proceeds to step 35, where it is determined whether or not the current detection distance α is greater than a predetermined distance 11m (point e in FIG. 2). If it is determined to be larger, the process proceeds to step 36.
In step 36, the current detection distance α is stored in the data “X-20” m (step d in FIG. 2) stored in step 28.
It is determined whether or not it is greater than (point). If it is, the process proceeds to the next step 37.

When it is determined in step 34 that the count value of the A counter has exceeded 50 m, it is determined that the vehicle has passed the area of the roadside reflector, and the flow proceeds to step 44 to release the alarm prohibition signal and to output the alarm. The prohibition flag is set to “0”. Next, at step 45, the A flag is set to "0" to reset the second rapid increase detection. When the detected distance α is smaller than 11 m in step 35, and when the detected distance α is smaller than “X−20” m in step 36, the distance to the object to be detected in front is too short. In either case, the flow proceeds to step 44, and the alarm prohibition signal is released. Here, the reason why the step 35 is provided is that the determination in the step 36 includes the detection distance X immediately before the rapid increase, and since this value fluctuates, “X−20” m is an absolute approach safe distance. Therefore, a fixed approach safe distance step 35 is additionally provided.

If it is determined in step 33 that the alarm prohibition signal has not been generated, step 37
Proceed to. In step 37, it is determined whether or not the detected distance Dn is smaller than the safe inter-vehicle distance Dr. _If the detected distance Dn is smaller, the process proceeds to step 38, where it is determined whether or not an alarm prohibition signal has been generated. If the alarm signal has already been generated in step 38 and the alarm prohibition flag is “1”, step 39
The generation of the alarm operation signal is stopped here. Thereafter, the flow returns to step 21, and the above operation is repeated. If it is determined in step 38 that the alarm prohibition flag is "0", an alarm operation signal is generated in step 40. In the case where the detection distance D _n is determined to be greater than the safe inter-vehicle distance Dr step 37, since there is no longer an alarm should the flow proceeds directly to step 39.

Further, when it is judged impossible to measure the detection distance D _n in step 22, in step 41, the distance measurement is possible is a predetermined distance traveling from only whether or not. That is, the count value of the B counter reset when the distance measurement becomes possible in step 25 is 50 m.
Is determined. If the measurement cannot be performed from the beginning, the B counter is initially set to 51 m, so that it is larger than 50 m and the process proceeds to step 42. If the B counter has been reset to 0 m in step 25, the determination is “NO” from this point until the vehicle runs 50 m, and the process proceeds to step 33. After traveling 50 m, the process proceeds to step 42, where it is determined whether the distance has not increased rapidly, that is, whether the A flag is "0". If there is no rapid increase, the process proceeds to 43, and if there is a rapid increase, the process proceeds to Step 33. In step 43, α and β are each set to 99 m. If measurement cannot be performed from the beginning, α and β are initially set to 99 m and remain unchanged.

Here, α and β are set to 99 m in step 43 for the following reasons. (A) of FIG.
As shown in the figure, the detection distance decreases from the detectable point p,
Once the distance decreases at the point p ″ and the distance decreases and the measurement becomes impossible at the point p ′, then when the distance is detected at the point q, the sudden increase is due to the difference from the point p ′. It is detected, but this is not a problem because it may be a roadside reflector,
As shown in (b), when the detection distance decreases from the detectable p point, and the measurement becomes impossible at the p ′ point without a sudden increase, next, when the distance detection of the q point is performed after a predetermined time, A sudden increase in the distance may be detected due to the difference from p 'even though the roadside reflector is not detected. Therefore, if the detection distances α and β are set to 99 m when the B counter has traveled 50 m, the difference between this point r (99 m) and the q point does not become a sudden increase in the distance. It will not be detected as a sudden increase in distance. After step 43, the flow proceeds to step 33.

[0025]

As described above, according to the present invention, the structure is simplified because the conventional stationary object discriminating means is not provided, and an alarm is issued immediately when a sudden increase in the detection distance is detected twice. Since the prohibition is performed, it is not necessary to count the traveling distance for a long time, and the alarm prohibition operation is quickened. In addition, the alarm prohibition is automatically released if the vehicle travels a predetermined distance without detecting the next rapid increase, and the alarm prohibition is automatically released when the vehicle approaches a predetermined distance even before traveling a predetermined distance. We can secure enough. Therefore, there is an excellent effect that the trouble of continuously detecting the roadside reflector and sounding the alarm signal when traveling on a curve is eliminated while securing the safety by the alarm signal.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing an embodiment of the present invention.

FIG. 2 is a waveform diagram showing a relationship between a traveling distance of an automobile and a detection distance measured by a distance measuring means in one embodiment of the present invention.

FIG. 3 is a flowchart illustrating a process of a control unit in FIG. 1;

FIG. 4 is a flowchart showing the processing of the control means of FIG. 1;

FIG. 5 shows steps 41 and 42 of the flowchart of FIG.
FIG. 43 is a waveform diagram for describing 43.

FIG. 6 is a plan view showing a manner in which a vehicle detects a roadside reflector while traveling on a curve.

FIG. 7 is a waveform diagram showing a waveform of a detection signal of a roadside reflector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automobile 2 Road 3 Roadside reflector 4 Beam 10 Distance measuring means 11 Control means 11a Rapid increase detecting means 11b Traveling distance measuring means after sudden increase 11c Traveling distance judging means 11d Warning control means 12 Warning means 13 Travel detecting means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Yamanoi 500 Kitawaki, Shimizu City, Shizuoka Prefecture Inside the Koito Manufacturing Shizuoka Plant (72) Inventor Michio Arai 500 Kitawaki Shimizu City, Shizuoka Prefecture Koito Manufacturing Shizuoka Plant (72) Inventor Yasufumi Kubota 500 Kitawaki, Shimizu City, Shizuoka Prefecture Koito Manufacturing Shizuoka Plant (72) Inventor Toshi Yanagisawa 500 Kitawaki Shimizu City, Shizuoka Prefecture Koito Manufacturing Shizuoka Plant (56) References JP-A-4-305184 (JP, A) JP-A-3-57984 (JP, A) JP-A-62-130500 (JP, A)

Claims (1)

(57) [Claims] 1. A distance measuring means for measuring a distance from a vehicle to a forward object, and an alarm means for issuing an alarm when the distance to the object measured by the distance measuring means is less than a predetermined safe inter-vehicle distance. In the reflector detecting device, a travel distance measuring means for measuring a travel distance of the vehicle, a sudden increase detection means for outputting a rapid increase signal when a sudden increase in the detection distance is detected by a signal from the distance measurement means, A sudden increase signal to measure the traveling distance of the vehicle from the point of sudden increase detection, and a sudden increase in traveling distance measuring means, and determine whether or not the traveling distance measured by the sudden increase in traveling distance measuring means has reached a predetermined set value. And a driving distance determining means for outputting a set value excess signal when the set value is reached, and an alarm means when the distance to the object measured by the distance measuring means becomes less than the safe inter-vehicle distance. If an alarm operation signal is generated and the alarm operation signal is generated when the sudden increase detection means generates the next sudden increase signal before the mileage of the vehicle reaches the set value in the mileage determination means, the generation is performed. Prohibition, the prohibition is released when the traveling distance determination means generates a set value excess signal, and a distance obtained by subtracting a predetermined distance from the detection distance immediately before the sudden increase in the distance to the object when the sudden increase in the detection distance is detected. A reflector detection device comprising: an alarm control unit that also releases the prohibition when the following conditions occur.