JP3642227B2 - Laser radar equipment for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser radar device for a vehicle that uses a laser radar to execute a predetermined process, for example, notification to a driver of the vehicle when detecting that a preceding vehicle has started while the vehicle is stopped.
[0002]
[Prior art]
As a conventional vehicle laser radar device, for example, as disclosed in Japanese Patent Application Laid-Open No. 8-276806, the distance between the vehicle ahead and the vehicle is detected while the vehicle is stopped, and the vehicle is stopped. There is known a technique for determining that the preceding vehicle has started and notifying the driver of the vehicle by sound or the like when the sequentially input inter-vehicle distance is increased by a predetermined value or more than the inter-vehicle distance when the vehicle is detected. ing.
[0003]
[Problems to be solved by the invention]
However, when a laser radar is used as a sensor for detecting the distance to the vehicle ahead, the beam width of the laser light of the laser radar is limited, and the horizontal direction covers a wide range of about 12 degrees by scanning, but the vertical In general, the direction beam width is as narrow as about 4 degrees from the viewpoint of preventing erroneous detection of signs on the road surface or above the road. For this reason, when the vehicle stops very close to the front vehicle to be detected, the reflector at the rear of the front vehicle is not irradiated even at the upper end of the vertical field of view of the laser beam, and the laser beam is below the reflector. It gets into the state where the vehicle ahead cannot be detected.
[0004]
In spite of the state in which distance measurement cannot be performed due to such a laser beam submergence phenomenon, laser emission is always continued even when the vehicle is stopped in order to quickly perform functions based on the start of the preceding vehicle, such as notification. When the distance measurement is performed, there are problems that the life of the laser diode is shortened and unnecessary power is consumed.
[0005]
The present invention has been made paying attention to such conventional problems, and aims to quickly perform a function based on the start of the forward vehicle, extend the life of the laser diode, and reduce wasteful power consumption. To do.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a vehicle laser radar device according to a first aspect of the present invention, which has a laser light emitting portion and a light receiving portion, and is mounted on the front portion of the vehicle. Laser radar ranging means for measuring the distance to the vehicle, stop detection means for detecting that the host vehicle is stopped, deceleration detection means for detecting that the host vehicle is decelerating, An approach detection means for detecting that the host vehicle is approaching the preceding vehicle based on the distance, a forward vehicle start detection means for detecting that the preceding vehicle has started based on the distance to the preceding vehicle, and the laser radar ranging Detection state detecting means for detecting whether or not the preceding vehicle is detected by the means, and a state in which the preceding vehicle is not detected after it is detected that the host vehicle is decelerating and approaching the preceding vehicle Has been detected And a light emission stop means for stopping the light emission of the laser by the laser radar distance measuring means when the vehicle is not in a state until the vehicle stops.
[0007]
According to a second aspect of the present invention, in the vehicular laser radar device according to the first aspect of the present invention, the vehicle start detection means for detecting the start of the own vehicle, and after the laser emission is stopped by the light emission stop means. And a light emission restarting means for restarting the laser emission by the laser radar distance measuring means when the start of the host vehicle is detected.
[0008]
According to a third aspect of the present invention, in the vehicular laser radar device according to the first or second aspect, the host vehicle is stopped and the front vehicle is being detected, and the front The vehicle is characterized by comprising means for notifying the driver that the preceding vehicle has started when the vehicle has started.
[0009]
According to a fourth aspect of the present invention, in the vehicular laser radar device according to the first or second aspect, the host vehicle is stopped, the front vehicle is being detected, and the front The vehicle is characterized by comprising means for controlling the distance to the preceding vehicle to be constant when the vehicle starts .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a vehicle laser radar apparatus according to the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of an embodiment of a vehicular laser radar apparatus according to the present invention.
[0011]
First, the configuration will be described. 10 is a laser radar distance measuring device that, when a laser beam emission start command is input, irradiates a pulsed laser beam every predetermined time and measures the distance between the vehicle and the vehicle ahead by the time it takes to receive the reflected laser beam. 30 is a notification device that notifies the driver of the host vehicle that a preceding vehicle has started by a buzzer or the like, and 40 detects the vehicle speed of the host vehicle and outputs a pulse signal corresponding to the vehicle speed. This is a vehicle speed detection device. Reference numeral 20 denotes a processing unit that executes the processing contents shown in FIG. 2 described later, such as whether or not the preceding vehicle has started while the host vehicle is stopped, and controls the notification device 30.
[0012]
Reference numeral 22 in the processing unit 20 is a distance change monitoring unit that receives an inter-vehicle distance signal from the laser radar distance measuring device 10 and monitors the inter-vehicle distance change. Reference numeral 23 denotes an own vehicle speed detection device 40. The vehicle speed monitoring unit inputs the vehicle speed pulse signal from the vehicle and calculates the vehicle speed data and monitors the change state of the vehicle speed. Further, 21 outputs a laser emission start command to the laser radar distance measuring device 10 every predetermined time or based on a vehicle speed signal from the own vehicle speed monitoring unit 23, and also outputs an output signal from the distance change monitoring unit 22 and the own vehicle speed monitoring. An output signal from the unit 23 is input, a laser emission stop command is output to the laser radar distance measuring device 10, and the light emission control of the laser radar distance measuring device 10 is performed. When it is determined from the output signal from the change monitoring unit 22 and the output signal from the own vehicle speed monitoring unit 23 whether to notify the driver that the preceding vehicle has started, It is a preceding vehicle start notification determination unit that performs notification by the notification device 30. The processing unit 20 is configured by a microcomputer.
[0013]
The processing contents of the control unit 2 will be described based on the flowcharts of FIGS.
When the system is activated, the stop behavior flag is set to OFF as an initial setting (step S100). The laser radar distance measuring device 10 is instructed to start laser emission (step S101), and the laser radar distance measuring device 10 starts distance measurement to the vehicle ahead. The inter-vehicle distance data measured by the laser radar distance measuring device 10 is input to the distance change monitoring unit 22 (step S102). The distance change monitoring unit 22 calculates the change in the inter-vehicle distance from the preceding vehicle from the input distance data (step S103).
[0014]
In addition, a pulse signal corresponding to the vehicle speed output from the host vehicle speed detection device 40 is input (step S104), the current vehicle speed of the host vehicle is calculated by counting the number of pulses (step S105), and the host vehicle speed is also determined. A change is detected (step S106).
[0015]
Next, the setting state of the stop behavior flag is determined (step S107). If the stop behavior flag is not set to ON, whether or not the host vehicle is decelerating from the change in the host vehicle speed detected in step S106. Determination is made (step S108). When the host vehicle is decelerating, it is next determined from the inter-vehicle distance change detected in step S103 whether the host vehicle is approaching the preceding vehicle (step S109). If YES in step S108 and YES in step S109, the vehicle is in a state of approaching the preceding vehicle while decelerating, so it is determined that the vehicle has entered a driving state for stopping and a stop behavior flag Is turned on (step S110), and the process returns to the distance measurement data input (step S102). If the host vehicle is not decelerating in step S108 or if the host vehicle is not approaching the preceding vehicle in step S109, it is determined that the vehicle is not in a driving state for stopping, and distance measurement data is input. The process returns to (Step S102).
[0016]
If the stop behavior flag is set to ON in step S107, that is, if the vehicle enters a driving state for stopping, is a forward vehicle detected based on the inter-vehicle distance measurement data detected in step S102? It is determined whether or not (step S111). Specifically, when the vehicle ahead is within the detectable distance (for example, 100 m) of the laser radar ranging device 10, the inter-vehicle distance data is within the detectable distance (for example, 100 m). Since the inter-vehicle distance data takes a value exceeding the detectable distance, the determination is made by comparing the inter-vehicle distance measuring data with the detectable distance.
[0017]
When the vehicle ahead is not detected, it is determined whether the vehicle is stopped or traveling by determining whether the vehicle speed calculated in step S105 is, for example, 5 km / h or more. (Step S112).
[0018]
If YES in step S107, YES in step S111, and YES in step S112, that is, the vehicle is decelerating while approaching the preceding vehicle while the preceding vehicle is being detected, Since the vehicle is not detected and the vehicle is stopped as it is, it is determined that there is a high possibility that the laser beam has entered below the reflector at the rear of the front vehicle, and the stop behavior flag is turned off (step S113). The distance measuring device 10 is instructed to stop the light emission (step S114). As a result, the laser diode of the laser radar ranging device 10 stops emitting light, thereby preventing unnecessary power consumption and extending the life of the laser diode.
[0019]
In this distance measurement interrupted state, a vehicle speed signal is input (step S115), and by calculating the host vehicle speed (step S116), it is determined whether or not the host vehicle is still stopped (step S117). When the own vehicle continues to stop, the vehicle speed signal input (step S115) and the own vehicle speed calculation (step S116) are repeated. If it is determined in step S117 that the vehicle has started, the process returns to step S101, a command is output to the laser radar ranging device 10 to start light emission, and ranging is resumed.
[0020]
On the other hand, if the preceding vehicle can be detected in steps S111 and S112, or if the vehicle has changed from the detected state of the preceding vehicle to the non-detected state but the vehicle has not stopped, the process proceeds to step S118 and the vehicle is still decelerating It is determined whether or not.
[0021]
If it is determined that the host vehicle is not decelerating, that is, if the vehicle changes from deceleration to a constant speed state or acceleration state, it is assumed that the state has changed from the behavior toward stopping and the stop behavior flag is turned off (step S119), returning to step S102.
[0022]
If it is determined in step S118 that the host vehicle is decelerating, it is determined whether the host vehicle has stopped (step S201). If the vehicle has stopped, the stop behavior flag is turned off (step S202). Then, it is determined whether or not the distance to the preceding vehicle is separated by a predetermined value (for example, 10 m) or more (step S203). NO), when the host vehicle is stopped (YES in step S201) and the vehicle ahead has started (YES in step S203), it is determined whether the host vehicle has stopped for a predetermined time (for example, 3 seconds) or more. (Steps S204 and S205) When the predetermined time has elapsed, the notification buzzer is turned on by the notification device 30 (step S206).
[0023]
【The invention's effect】
As described above, the present invention changes from a state in which the preceding vehicle is detected to a state in which it is not detected when the vehicle approaches and stops in front of the preceding vehicle. Since the light emission was stopped, the vehicle was stopped too close and the laser beam diverged under the vehicle in front, so that the vehicle ahead could not be detected. Power consumption and a decrease in the life of the laser diode can be avoided, and when the vehicle ahead is detected even when the vehicle is stopped, the laser emission is not stopped and the predetermined processing is performed. Predetermined processing such as notification for starting and inter-vehicle distance control can be quickly executed.
In addition, when the vehicle starts, the distance measurement and predetermined processing can be performed by automatically restarting the laser emission.
[Brief description of the drawings]
FIG. 1 is a configuration block diagram showing an embodiment of a vehicle laser radar device according to the present invention.
FIG. 2 is a flowchart for explaining processing contents of a control unit;
FIG. 3 is a flowchart for explaining processing contents of a control unit;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Laser radar ranging device 20 Processing part 21 Laser light emission control part 22 Distance change monitoring part 23 Own vehicle speed monitoring part 24 Front vehicle start notification determination part 30 Notification apparatus 40 Own vehicle speed detection apparatus

Claims (4)

Laser radar ranging means that has a laser light emitting part and a light receiving part, is mounted on the front part of the vehicle and measures the distance to the preceding vehicle, and a stop detection means that detects that the host vehicle is stopped,
Deceleration detection means for detecting that the host vehicle is decelerating;
An approach detecting means for detecting that the host vehicle is approaching the preceding vehicle based on the distance to the preceding vehicle;
Forward vehicle start detection means for detecting that the forward vehicle has started based on the distance to the forward vehicle;
Detection state detection means for detecting whether or not a forward vehicle is detected by the laser radar distance measurement means ;
When it is detected that the host vehicle is decelerating and approaching the preceding vehicle, the leading vehicle is not detected, and when the undetected state continues until the host vehicle stops, Light emission stopping means for stopping laser light emission by the laser radar ranging means;
A vehicle laser radar device comprising: The vehicle laser radar device according to claim 1,
Own vehicle start detection means for detecting the start of the own vehicle;
When the start of the host vehicle is detected after the laser emission is stopped by the light emission stopping means, the light emission restarting means for restarting the laser emission by the laser radar ranging means;
A vehicle laser radar device comprising: In the vehicle laser radar device according to claim 1 or 2,
For vehicles, comprising means for notifying the driver that the preceding vehicle has started when the host vehicle is stopped, the preceding vehicle is being detected, and the preceding vehicle has started Laser radar device. In the vehicle laser radar device according to claim 1 or 2,
For vehicles, comprising means for controlling the distance to the preceding vehicle to be constant when the host vehicle is stopped, the preceding vehicle is being detected, and the preceding vehicle has started Laser radar device.

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