JP2548082Y2 - Light emission notification device for inter-vehicle distance detection / warning device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emission notification device for an inter-vehicle distance detection / warning device, which is devised so that a person outside the vehicle can be informed that laser light is being emitted during optical axis adjustment work. Things.

[0002]

2. Description of the Related Art The causes of rear-end collisions mainly due to trucks are:
Drivers who fall asleep or drunk driving account for the majority.
Under such circumstances, an inter-vehicle distance detection / warning device has been developed which detects the inter-vehicle distance between the own vehicle and the preceding vehicle and issues a warning to the driver when the distance becomes less than a certain distance. ing.

[0003] The outline of the current state of this device is that a laser beam emitted from a light emitting section of a laser radar unit is emitted forward from the own vehicle, and a laser beam reflected by a reflector on the rear surface of a front vehicle is received. The light is received by the part, the distance between the vehicles is calculated by the control unit from that time,
When the inter-vehicle distance becomes smaller than the braking distance or the idling distance of the own vehicle, the buzzer in the vehicle compartment sounds.

The laser radar unit of the inter-vehicle distance detecting / warning device emits laser light after the vehicle speed detected by the vehicle speed sensor becomes equal to or higher than a predetermined speed (for example, 35 km / h).

On the other hand, when a vehicle having the above-described inter-vehicle distance detection / warning device is shipped, the optical axis of the laser beam emitted from the laser radar unit must be adjusted. That is, it is necessary to adjust the installation position of the laser light emitting unit so that the laser light is emitted from the laser radar unit in a predetermined direction parallel to the longitudinal center line of the vehicle and horizontally forward. When performing this adjustment, for example, by turning on an optical axis adjustment switch, laser light is emitted from the laser radar unit even when the vehicle speed is zero.

Therefore, when adjusting the optical axis, an operator has a reflector at a predetermined distance in front of the vehicle toward the vehicle, reflects the emitted laser light, and can receive the reflected light with the laser radar unit. The optical axis is adjusted by checking whether or not the optical axis has been adjusted.

[0007]

The laser light emitted from the laser radar unit is near-infrared light and cannot be seen by human eyes. For this reason, the worker holding the reflection plate could not know whether or not the laser light was being emitted, and it was difficult to adjust the optical axis. In addition, another worker may enter between the laser radar unit and the reflection plate and cut off the laser light without knowing that the laser light is being emitted. At this time, the optical axis adjustment is hindered. .

The present invention has been made in view of the above-mentioned prior art, and has as its object to provide a light emission notification device of an inter-vehicle distance detection / warning device capable of reliably notifying that laser light is being emitted during optical axis adjustment. .

[0009]

In order to solve the above-mentioned problems, according to the structure of the present invention, when a vehicle speed detected by a vehicle speed sensor is equal to or higher than a predetermined value, a laser beam emitted from a laser radar unit of the own vehicle is reflected by a preceding vehicle. Detects the time until the vehicle returns and calculates the distance between the vehicles, and if the distance between vehicles becomes smaller than the safe distance between vehicles determined based on the braking distance and idle running distance of the vehicle, an alarm is issued. In the inter-vehicle distance detection / warning device having a control unit, the laser radar unit emits laser light even when the vehicle speed is zero,
An optical axis adjusting means for issuing a command to the control unit,
When a command is issued from the optical axis adjusting means and the laser light is being emitted, the operating means is controlled by the controller to notify the outside of the vehicle that the laser light is being emitted. Features.

[0010]

When the laser beam is radiated from the laser radar unit for adjusting the optical axis, the notifying means is activated, so that a person outside the vehicle can be informed that the laser beam is being radiated.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention.
FIG. 2 is an explanatory view showing an outline of a mounting position of the present apparatus, and FIG. 3 is a configuration diagram showing a laser radar unit. The laser radar unit 1 has a light emitting unit 2 and a light receiving unit 3. The light emitting unit 2 includes a laser diode driving circuit 4, a laser diode 5, and a light emitting lens 6, and emits a laser beam in a pulsed manner at regular intervals. The light receiving section 3 includes a light receiving lens 7, which receives laser light reflected by a reflector of a front vehicle, a photodiode 8, an amplifier 9, a signal processor 10, and the like. These light emitting units 2
The inter-vehicle distance D (= Δt / 2 × light speed) is obtained by the distance detection circuit 11 from the time difference Δt between the light emission by the light receiving unit 3 and the light reception by the light receiving unit 3.

An inter-vehicle distance signal, which is a detection value of the laser radar unit 1, is input to a control unit 14 installed below the seat 13 of the truck 12.
As shown in FIG. 2, the laser radar unit 1 is assembled in a bumper 15 of a truck 12 and emits a laser beam 16.

A vehicle speed sensor 17 detects the vehicle speed from a rotating portion of the transmission. The detection signal of the vehicle speed sensor 17 is input to the control unit 14.

Reference numeral 18 denotes a display unit incorporated in the instrument panel in front of the driver's seat. The display unit 18 is provided with a display unit for the distance between vehicles, a buzzer that issues an alarm, a lamp that flashes when an alarm is generated, and the like to call the driver's attention. In addition, they will report.

Reference numeral 19 denotes a wiper switch which functions as an example of an environment sensor, and its ON and OFF signals are inputted to the control unit 14. That is, when the wiper switch 19 is turned on, it is determined that it is raining.

The other environmental sensors 20 include a raindrop sensor, a road surface sensor (G sensor), a temperature sensor, a slip sensor, and the like. According to the raindrop sensor, it is detected that it is rainy, that is, the road surface is in a wet state,
The road surface sensor detects whether the road surface is a bumpy road, or other conditions, and the temperature sensor detects the weather and thus the road surface conditions, for example, a frozen state, in combination with the detection results of other sensors. According to the slip sensor, it is detected from the rotational speed difference between the front wheels and the rear wheels whether or not the road surface is likely to slip, that is, whether it is a low μ road or a high μ road. The detection result is input to the control unit 14.

The control unit 14 performs a predetermined operation based on signals from each section of the apparatus and controls the entire system. The control unit 14 controls, in principle, to operate the laser radar unit 1 on condition that the vehicle speed signal detected by the vehicle speed sensor 17 becomes 35 km / h or more, and in this embodiment, adjusts the optical axis. When the switch 14a is turned on, control is performed so that the laser radar unit 1 operates unconditionally. Moreover, when the laser radar unit 1 is operated by turning on the optical axis adjustment switch 14a, the power of the emitted laser light 16 is reduced to, for example, about 1/10.

Therefore, the inter-vehicle distance detecting / warning apparatus shown in FIGS.
h does not work unless the vehicle is running above
When the truck 4a is turned on, the laser radar unit 1 can be operated even when the truck 12 stops.

Further, in this embodiment, a notification lamp 50 is provided on the front surface of the laser radar unit 1. The notification lamp 50 is provided at a position visible to an operator outside the vehicle in front of the vehicle, and emits light having a wavelength that can be seen by human eyes. The notification lamp 50 is turned on under the control of the control unit 14 when the optical axis adjustment switch 14a is turned on and the laser beam is emitted from the light emitting unit 2. When the switch 14a is opened,
The notification lamp 50 is turned off. Therefore, when the optical axis is adjusted, the notification lamp 50 is turned on, so that the worker having the reflector can surely know that the laser beam is being emitted, and the work becomes easier. Also, other workers outside the vehicle can know the emission of the laser light, and can be careful not to block the laser light.

Here, a description will be given of a calculation process leading to the generation of an alarm by the apparatus of this embodiment during actual running.

The distance between the host vehicle and the preceding vehicle, that is, the inter-vehicle distance D (m) is obtained by the laser radar unit 1 as described above. The vehicle speed Vf (m / s) is calculated by the vehicle speed sensor 1
7 is detected. The speed Va (m / s) of the preceding vehicle is obtained by calculation from a change in the inter-vehicle distance D per minute time. That is, the front vehicle speed Va is larger than the relative speed between the own vehicle and the front vehicle.
Is required.

On the other hand, the time required for the driver to judge the danger and depress the brake pedal, ie, the idle running time Td (s), the time for the driver to judge the danger, ie, the judgment time Tx
(S) and the vehicle deceleration α ₁ (m / s ²⁾ and preceding vehicle deceleration α ^₂ (m / s ₂₎ is stored in the memory in advance the control unit 14. As the decelerations α ₁ and α ₂ , values assuming full braking are stored, and normally, α ₁ = α ₂ .

The braking distance L ₁ of the front vehicle is equal to the front vehicle speed Va.
L ₁ = Va ² / 2α _2, and deceleration α ₂ . Idling-run distance L ₂ of the vehicle, the vehicle speed Vf and the idling-run time Td,
L ₂ = (Td + Tx) Vf is determined from the determination time Tx. Braking distance L ₃ of the vehicle is determined by L ₃ = Vf ² / 2α ₁ from deceleration alpha ₁ Tokyo between the vehicle speed Vf.

Therefore, the condition for generating the alarm is that the sum of the preceding vehicle braking distance L ₁ and the inter-vehicle distance D is equal to the own vehicle braking distance L _3.
Triggered by the when and becomes smaller than the sum of the vehicle air-run distance L _2. That is, Va ² / 2α ₂ + D <Vf ² / 2α ₁ + (Td + Tx) Vf Therefore, D <(Td + Tx) Vf + (Vf ² / 2α ₁ −Va ² / 2α ₂ ) = Ds (safety vehicle distance). Sometimes, an alarm is generated from the display unit 18.

As can be seen from this equation, the safe inter-vehicle distance D
Since the speed of the preceding vehicle is taken into account in the calculation of s, the optimal warning time depends on whether the preceding vehicle 22 is traveling at high speed or low speed, whether the vehicle is accelerating or decelerating, and whether or not the vehicle is stopped. It is decided. When the front vehicle 22 is stopped, Va = 0 in the equation. By the way, on a wet road surface or a frozen road surface in rainy weather, the decelerations α ₁ and α ₂ of the vehicle become small.

If it is detected that the wiper switch 19 has been turned on, the control unit 14 changes the numerical values of the decelerations α ₁ and α ₂ and changes the inter-vehicle distance at which the alarm is generated. That is, on a wet road surface, etc., the safe inter-vehicle distance Ds automatically changes, and the warning issuance time is hastened. For example, deceleration α ₁ (= α ₂ ) on a dry road
Is about 0.3G, then 0.2G depending on the road conditions
(For example, a wet road surface) and 0.1 G (for example, a frozen road, a snowy road, etc.).

Next, a specific example of control by the control unit 14 in the apparatus of this embodiment will be described with reference to the flowchart of FIG.

First, an initial value is set in step (1). That is, the idle running time Td, the determination time Tx, the decelerations α ₁ , α ₂ (α ₁ = α) of the own vehicle and the preceding vehicle at the time of full braking
₂ ) is set.

In step (2), it is determined whether or not the optical axis adjustment mode is set, specifically, whether or not the optical axis adjustment switch 14a is turned on. When in the optical axis adjustment mode, the beam output is set to 1/1 of the output during normal running.
As 0, the laser beam 16 is emitted from the light emitting section 2 of the laser radar unit 1 (step (3)). Further, the notification lamp 50 is turned on (step (4)). In step (5), the detected inter-vehicle distance is displayed on the display unit 18 and the fact that the alarm function is not activated is displayed.

If it is determined in step (2) that the mode is not the optical axis adjustment mode, and if it is determined in step (6) that the vehicle speed is 35 km / h or more, the process proceeds to step (7).
The laser beam is emitted from the light emitting unit 2 of the laser radar unit 1 by increasing the beam output to make the output during normal driving.

While the vehicle is running, the inter-vehicle distance D is calculated in step (8) based on the above formula, and in step (9), the own vehicle speed Vf is detected by the vehicle speed sensor 17.
Is detected, and in step (10), the preceding vehicle speed Va is determined from the change in the inter-vehicle distance D and the own vehicle speed Vf as described above.

Next, the environment, that is, the road surface condition is detected by the environment sensor 20 and the like (step (11)). For example,
It is detected whether the wiper switch 19 is in the ON state.

Next, the decelerations α ₁ and α _{2 of} the own vehicle and the preceding vehicle are changed according to the road surface condition (step (1)).
2)). If the environment information is not detected in the previous step (11), the default decelerations α ₁ and α ₂ are used as they are.

Next, in step (13), the own vehicle speed Vf, the preceding vehicle speed Va, detected or calculated as described above,
The safe inter-vehicle distance Ds is obtained from the decelerations α ₁ , α _{2, and the} like. This safe inter-vehicle distance Ds is appropriately corrected in consideration of the speed of the preceding vehicle and according to the road surface condition.

If it is determined in step (14) that the inter-vehicle distance D is smaller than the safe inter-vehicle distance Ds, then in step (15), the front vehicle speed Va is compared with the host vehicle speed Vf. When the preceding vehicle speed Va is high, it is not necessary to generate an alarm because the inter-vehicle distance D is increasing, and the process proceeds to step (16), no alarm is issued, and the display unit 18 displays the inter-vehicle distance. The distance is displayed. Also, when it is determined in step (14) that the inter-vehicle distance D is larger than the safe inter-vehicle distance Ds, the process proceeds to step (16).

When the preceding vehicle speed Va is smaller than the own vehicle speed Vf, the warning is issued to the display unit 21 because the vehicle is in the area to be warned and is gradually approaching. The inter-vehicle distance D is also displayed (step 17).

In the above embodiment, the optical axis adjustment switch 14
Although the optical axis adjustment mode was set by inputting a,
A pseudo vehicle speed signal indicating that the vehicle speed is equal to or higher than 35 km / h may be input to the control unit 14 to shift to the optical axis adjustment mode.

In the above embodiment, the notification lamp 50 is turned on when the laser beam is emitted in the optical axis adjustment mode. However, a buzzer, a chime or the like is sounded, or the head lamp of the own vehicle is turned on. Alternatively, a worker outside the vehicle may be informed that the laser light is being emitted by causing a hazard lamp to blink or a horn to sound.

[0040]

According to the present invention, as described above in detail with the embodiment, when the laser beam is being emitted for adjusting the optical axis, the notifying means is activated, so that the worker outside the vehicle can use the laser beam. Radiation can be surely known, and the optical axis adjustment work can be easily performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a light emission notification device of an inter-vehicle distance detection / warning device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic mounting positional relationship of each component of the apparatus shown in FIG.

FIG. 3 is an explanatory diagram of a laser radar unit.

FIG. 4 is a flowchart showing the operation of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser radar unit 2 Light emitting part 3 Light receiving part 7 Vehicle speed sensor 14 Control unit 14a Optical axis adjustment switch 16 Laser light 18 Display unit 50 Notification lamp

Claims (1)

(57) [Scope of request for utility model registration] When a vehicle speed detected by a vehicle speed sensor is equal to or higher than a predetermined value, a time until a laser beam emitted from a laser radar unit of the own vehicle is reflected by a preceding vehicle and returns is detected to determine an inter-vehicle distance. In the following distance detection / warning device having a control unit for issuing an alarm when the following distance becomes smaller than the safe distance between vehicles determined based on the braking distance of the own vehicle and the idling distance, An optical axis adjusting unit that issues a command to the control unit so that the laser beam is emitted from the laser radar unit even when the laser beam is zero, and when the laser beam is emitted by issuing an instruction from the optical axis adjusting unit, A light emitting device for an inter-vehicle distance detecting / warning device, comprising: a notifying device that operates under the control of a controller to notify the outside of the vehicle that laser light is being emitted. .