JP3663923B2 - Vehicle distance notification device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for measuring and notifying an inter-vehicle distance, and particularly to detecting and notifying dirt adhering to an inter-vehicle distance measuring unit.
[0002]
[Prior art and its problems]
As a detector for detecting the distance to the object, a very thin laser beam of about 0.1 to 0.2 degrees is scanned in the horizontal direction to measure a wide range of about 12 to 15 degrees, and the distance to the object is measured. Scanning laser radars that measure the direction are known. In this scanning laser radar, the beam emitted from the laser diode is reflected by a mirror, and scanning is performed by rotating the mirror with a motor.
This scanning laser radar can be used to measure the inter-vehicle distance to the front vehicle and notify the passengers of the approach according to the degree of approach to the front vehicle.
[0003]
By the way, if dirt adheres to the laser light transmission window or light receiving window of the laser radar, the distance measurement performance may deteriorate depending on the degree of adhesion, or the adhering dirt may be mistaken as an obstacle near the vehicle and an approach notification is made. There are things to do.
[0004]
An object of the present invention is to detect and notify dirt adhering to the inter-vehicle distance measuring unit.
[0005]
[Means for Solving the Problems]
The present invention will be described with reference to FIG. 1 showing the configuration of an embodiment.
(1) The invention of claim 1 is provided with measuring means 1 for measuring the distance to the front vehicle by changing the measurement direction while scanning the front of the host vehicle in the horizontal direction, and the inter-vehicle distance for notifying the inter-vehicle distance to the front vehicle. It is a notification device, and when a distance measurement value equal to or less than a predetermined value is detected continuously for a preset time in substantially the same measurement direction, a contamination adhesion notification that notifies the measurement means 1 that contamination has adhered Means 3 and 6 are provided to achieve the above object.
(2) The inter-vehicle distance notification device according to claim 2 sets different times as the preset time in the measurement direction of the central portion of the scanning range of the measuring means 1 and the measurement direction of the end portion, thereby measuring the end portion. The set time for the direction is longer than the set time for the measurement direction at the center .
[0006]
In the section of the means for solving the above-described problem, a diagram of an embodiment is used for easy understanding of the description. However, the present invention is not limited to the embodiment.
[0007]
【The invention's effect】
(1) According to the first aspect of the present invention, when a distance measurement value equal to or less than a predetermined value is continuously detected for a preset time in substantially the same measurement direction, dirt is attached to the measurement means. Since the notification is made, it is possible to detect dirt that cannot be detected by the dedicated dirt detection light receiving element, and it is possible to prompt the occupant to perform cleaning work and prevent the distance measurement performance from being deteriorated.
(2) According to the invention of claim 2 , different times are set as the set time for determining dirt adhesion in the measurement direction at the center of the scanning range of the measuring means and the measurement direction at the end, Since the set time for the measurement direction is longer than the set time for the center measurement direction, the dirt detection operation at the end of the scanning range is suppressed, and distance measurement is performed for guardrails and parallel running vehicles that run close to each other. The probability of misidentifying a value as dirty can be reduced.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram illustrating a configuration of an inter-vehicle distance notification device according to an embodiment.
The scanning laser radar 1 measures a wide range by scanning a thin laser beam in the horizontal direction, and measures the distance and direction to an object in front of the vehicle. The vehicle speed sensor 2 detects the traveling speed of the vehicle. The inter-vehicle distance notification device 3 is composed of a microcomputer and its peripheral parts, calculates the inter-vehicle distance to the preceding vehicle based on the measurement result by the laser radar 1, and displays the approach indicator 4 according to the inter-vehicle distance and the traveling speed of the own vehicle. The buzzer 5 notifies the approach. The inter-vehicle distance notification device 3 also executes a stain detection program to be described later to detect stains adhering to the laser radar 1 and displays them on the stain notification display 6 to prompt a cleaning operation.
[0009]
FIG. 2 is a diagram showing details of the scanning laser radar 1.
The laser light emitted from the light emitting element 11 passes through the light transmission lens 12 and is reflected by the mirrors 13 and 14 and is emitted from the light transmission window 15 to the front of the vehicle. The mirror 14 is provided with a scanning mechanism for changing the tilt, and as shown in FIG. 3, a thin laser beam of 0.15 degrees is scanned 80 steps in the horizontal direction in front of the vehicle, and a wide range of ± 6 degrees is obtained. Measure distance. Laser light reflected by an obstacle such as a front wheel enters from the light receiving window 16, is collected by the light receiving lens 17, and is received by the light receiving element 18.
[0010]
In this embodiment, the beam numbers for each step in the 80-step scanning are 1 to 80 in order from the right end as shown in FIG. Each of the 80 beam numbers corresponds to 80 directions at intervals of 0.15 degrees in front of the vehicle. The distance measurement results in the 80 directions are stored for each step number in the memory of the inter-vehicle distance notification device 3 as shown in FIG. Further, the 80-direction beam from the right end to the left end is divided into three regions, 35 to 44 are set as the central beam, and 1 to 34 and 45 to 45
80 is an end beam.
[0011]
The dirt detection light receiving element 19 receives the laser beam reflected by the dirt attached to the light transmission window 15 and sends a dirt detection signal to the dirt notification display 6 when the amount of received light exceeds a predetermined level to notify the dirt adhesion. To do.
[0012]
Incidentally, the dirt adhering to the laser radar 1 adheres not only to the light transmission window 15 but also to the light receiving window 16. Since the dirt adhering to the light receiving window 16 cannot be detected by the dirt detecting light receiving element 19, it is not notified and is left as it is. As a result, the ranging performance of the laser radar 1 is degraded. Also, dirt on the light transmission window 15 may not be detected by the dirt detection light receiving element 19 depending on the degree of adhesion, and is left as it is as described above, resulting in a decrease in distance measurement performance. Furthermore, the dirt adhering to the light transmission window 15 or the light receiving window 16 may be mistaken as a nearby obstacle, and an approach notification may be performed.
[0013]
Therefore, in this embodiment, even when the dirt detection light-receiving element 19 has not detected the adhesion of dirt, the light transmission window 15 or the like, based on the 80-direction distance measurement data measured by the scanning laser radar 1. Dirt adhering to the light receiving window 16 is detected. That is, if the 80-direction distance measurement data includes data that is less than or equal to a predetermined value, the data is invalidated for the time being. Then, when the distance measurement data in substantially the same direction continues to be a predetermined value or less continuously for a preset time, it is determined that dirt is attached to a portion corresponding to the direction of the light transmission window 15 or the light reception window 16. Then, it notifies the adhesion of dirt and prompts the cleaning work.
[0014]
5 and 6 are flowcharts showing the dirt detection process. The operation of the embodiment will be described with reference to these flowcharts.
The microcomputer of the inter-vehicle distance notification device 3 executes this dirt detection program at predetermined time intervals. In step 1, the vehicle speed detection value by the vehicle speed sensor 2 is compared with a predetermined value to confirm whether or not the host vehicle is traveling. When the vehicle is not running, the process proceeds to step 3 to stop the distance measuring operation by the scanning laser radar 1 and end the dirt detection process.
[0015]
When the vehicle is traveling, the process proceeds to step 2 and the scanning laser radar 1 performs a distance measuring operation. In the following step 4, it is confirmed whether or not the light transmission window 15 is detected by the dirt detection light receiving element 19, and if the dirt is detected, the process proceeds to step 5. In step 5, the dirt notification display 6 notifies the dirt attachment of the light transmission window 15 and prompts the occupant to clean the dirt.
[0016]
If the contamination detection light receiving element 19 does not detect the contamination of the light transmission window 15, the process proceeds to step 6 where the distance measurement result by the scanning laser radar 1 is confirmed, and the distance data of the beams 1 to 80 in the 80 directions are It is confirmed whether or not the data contains a predetermined value or less. If there is no distance data equal to or smaller than the predetermined value, the distance measurement data invalidation counters C1 and C2, which will be described later, are cleared in step 8, and the stain notification operation is stopped in the subsequent step 9 to end the processing.
[0017]
If the 80-direction distance measurement data includes data less than or equal to the predetermined value, the process proceeds to step 7 to invalidate the distance measurement data less than or equal to the predetermined value. For example, all distance measurement data below a predetermined value is set to zero. In the next step 10, it is checked whether or not the invalid ranging data is the data of the central beam of 35 to 44. If it is the data of the central beam, the process proceeds to step 11 and if it is the data of the end beam, the process proceeds to step 14. move on.
[0018]
If the center beam distance measurement data is invalidated, the counter C1 that counts the number of times the center beam distance measurement data is invalidated is incremented in step 11. In the next step 12, it is confirmed whether or not the counter C1 is equal to or greater than the predetermined value K1, that is, whether or not the distance measurement data has been invalidated continuously for a preset time (dirt detection program execution time interval × K1). If the distance measurement data of the central beam is invalidated for the set time, it is confirmed in step 13 that dirt is attached to the dirt notification display 6 at the center of the light transmission window 15 or the light receiving window 16. Display and prompt the passenger to clean the dirt.
[0019]
On the other hand, if the distance measurement data of the end beam is invalidated, in step 14, the counter C2 that counts the number of times the distance measurement data of the end beam is invalidated is incremented. In the following step 15, it is confirmed whether the counter C2 is equal to or larger than the predetermined value K2, that is, whether the distance measurement data has been invalidated continuously for a preset time (execution time interval of the dirt detection program × K2).
[0020]
Here, K2 is set to a value larger than K1. As a result, it is possible to suppress the dirt detection operation at the beam end, and to reduce the probability of misidentifying the distance measurement data for the guardrail and the parallel running vehicle running in the vicinity as dirt.
[0021]
If the distance measurement data of the end beam has been invalidated for a set time, in step 16, the dirt notification indicator 6 is contaminated with the light transmitting window 15 or the edge of the light receiving window 16. Is displayed and prompts the passenger to clean the dirt.
[0022]
In this way, if the distance measurement data obtained by scanning the laser beam in the horizontal direction contains data that is less than a predetermined value, which is not normal, the distance measurement data is invalidated. Therefore, it is possible to prevent erroneous inter-vehicle distance notification and approach notification from being performed using such distance measurement data.
[0023]
In addition, when the distance measurement data in substantially the same distance measurement direction has been invalidated for a preset time, the dirt measurement is reported to the occupant because the distance measurement unit is contaminated. Also, dirt that cannot be detected by the dirt detection light-receiving element can be detected, and the occupant can be encouraged to perform cleaning work to prevent the distance measurement performance from being deteriorated.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an embodiment.
FIG. 2 is a diagram showing details of a scanning laser radar according to an embodiment.
FIG. 3 is a diagram showing beam numbers for step scanning of a laser beam.
FIG. 4 is a diagram showing classification of ranging data in 80 directions.
[Figure 5]
FIG. 6 is a flowchart illustrating a stain detection program according to an embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Scanning type laser radar 2 Vehicle speed sensor 3 Inter-vehicle distance notification device 4 Approach indicator 5 Buzzer 6 Dirt notification indicator 11 Light emitting element 12 Light transmitting lens 13, 14 Mirror 15 Light transmitting window 16 Light receiving window 17 Light receiving lens 18 Light receiving element 19 Dirt detection light receiving element

Claims (2)

A vehicle distance notifying device comprising a measuring means for measuring the distance to the front vehicle by changing the measurement direction while scanning the front of the host vehicle in the horizontal direction, and reporting the inter-vehicle distance to the front vehicle,
When a distance measurement value equal to or less than a predetermined value is continuously detected for a preset time in substantially the same measurement direction, it is provided with a dirt adhesion notifying means for notifying that the dirt is attached to the measurement means. Inter-vehicle distance notification device. In the inter-vehicle distance notification device according to claim 1,
As the preset time, different times are set for the central measurement direction and the end measurement direction of the scanning range of the measuring means, and the set time for the end measurement direction is set for the central measurement direction. An inter-vehicle distance notification device characterized by being longer than time .

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