JPH06313771A - Space filter type speed measuring apparatus, speed control system having the same and automobile - Google Patents

Abstract

PURPOSE:To provide a space filter type speed measuring apparatus, a speed control system having the same and an automobile in which adherence of dirt from an object to be measured to a light passing surface is prevented and maintenance at the time of dirt adherence is facilitated. CONSTITUTION:An electrostatic type dust attracting unit 10 is so provided as to surround a light passing space of a space filter type speed measuring apparatus 1. Thus, fine substance such as dusts, etc., is attracted to a metal plate 11 or 12 before it reaches a light passing surface 6 of the apparatus 1 or an optical system to prevent adherence of dirt to the surface 6 or the optical system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatial filter type speed measuring device which measures the ground speed in a non-contact manner, and relates to a technique for preventing dirt from adhering to the device or improving the maintainability against dirt. Further, the present invention relates to a speed control system and an automobile equipped with this device.

[0002]

2. Description of the Related Art Conventionally, in a vehicle equipped with a spatial filter type velocity measuring device, an air rectifying plate is provided around a light passage surface of the device in parallel with a light receiving lens for receiving detection light, and when the vehicle is moved, It is known that the air conditioning plate adjusts the air flow so that it is parallel to the light receiving lens to prevent dirt from adhering to the portion where the detection light passes and to obtain an accurate ground speed. (JP-A-6
3-286772).

[0003]

However, in such a system, when the vehicle is stationary, dirt easily adheres to a portion through which the detection light passes. Further, when dirt adheres, there is a problem that it is difficult to perform maintenance by removing dirt so that the detection light is not partially blocked.

The present invention solves the above-mentioned problems. By providing an electrostatic dust suction device or a dirt prevention hood, dirt adhesion is prevented, and maintenance at the time of dirt adhesion is facilitated. An object of the present invention is to provide a spatial filter type speed measuring device, a speed control system including the same, and an automobile. Further, by using a water repellent resin for the light passing surface, a spatial filter type speed measuring device that minimizes a measurement error caused by water droplets adhering to the light passing surface, a speed control system including the same, and an automobile are provided. The purpose is to do.

[0005]

In order to achieve the above object, the invention of claim 1 is provided with an optical system and a photodetector which constitute a spatial filter for receiving light from an object to be measured, and the photodetector. In the spatial filter type velocity measuring device for calculating the velocity of the measuring object based on the frequency signal detected by, the electrostatic dust adsorbing device is arranged so as to surround the light passage space of the optical system. . According to a second aspect of the present invention, in the spatial filter type velocity measuring device according to the first aspect, a part of the surface of the dust adsorbing portion of the electrostatic dust adsorbing device is positively charged, and another portion or all the remaining portions. Is negatively charged. According to a third aspect of the present invention, an optical system and a photodetector that form a spatial filter that receives light from the measurement target are provided, and the velocity of the measurement target is determined based on the frequency signal detected by the photodetector. In the spatial filter type velocity measuring device for calculation, a peelable transparent adhesive seal is provided on the light passage surface.

According to a fourth aspect of the present invention, there is provided an optical system which constitutes a spatial filter for receiving light from the object to be measured and a photodetector, and the object to be measured is based on a frequency signal detected by the photodetector. In the spatial filter type velocity measuring device for calculating the velocity of, the detachable transparent plate is provided on the light passage surface. According to a fifth aspect of the present invention, an optical system that constitutes a spatial filter that receives light from the measurement target and a photodetector are provided, and the velocity of the measurement target is determined based on the frequency signal detected by the photodetector. The spatial filter type speed measuring device for calculation is provided with a ventilation device that ventilates the light passage space from an air conditioner ventilation system of the vehicle or a ventilation system provided independently of the air conditioner. According to a sixth aspect of the present invention, in the spatial filter type velocity measuring device according to the fifth aspect, a dustproof filter is provided in a ventilation passage from the ventilation system.

According to a seventh aspect of the invention, in the spatial filter type velocity measuring device according to the fifth aspect, a temperature sensor for measuring the temperature of the velocity measuring device or a specific portion of the vehicle is provided,
The ventilation temperature of the ventilation device is changed according to the temperature measured by the temperature sensor. The invention according to claim 8 is provided with an optical system and a photodetector that constitute a spatial filter for receiving light from the measurement target, and the speed of the measurement target is determined based on the frequency signal detected by the photodetector. In the spatial filter type velocity measuring device for calculation, a stain preventing hood is arranged so as to surround the light passage space of the optical system, and the tip portion of the stain preventing hood is formed in a divergent shape. According to a ninth aspect of the present invention, an optical system and a photodetector that form a spatial filter that receives light from the measurement target are provided, and the velocity of the measurement target is determined based on the frequency signal detected by the photodetector. In the spatial filter type velocity measuring device for calculating, a transparent plate or a transparent adhesive seal is provided on the light passage surface, and the transparent plate or the transparent adhesive seal is a water-repellent resin, or
A water-repellent resin is applied or coated on the transparent plate or the transparent adhesive seal.

According to a tenth aspect of the present invention, there is provided an optical system and a photodetector which constitute a spatial filter for receiving light from the measurement target, and the measurement target is based on the frequency signal detected by the photodetector. In the spatial filter type velocity measuring device for calculating the velocity of, the transparent plate is provided on the light passage surface with an inclination with respect to the horizontal plane. The invention according to claim 11 is a speed control system comprising the spatial filter type speed measuring device according to any one of claims 1 to 10, wherein the speed is controlled by controlling a brake or an accelerator by the output of this device. The invention of claim 12 is an automobile equipped with the speed control system according to claim 11.

[0009]

According to the structure of claims 1 and 2, a part of the surface of the dust adsorbing portion of the electrostatic dust adsorbing device is positively charged, and another part or all of the remaining part is negatively electrifying. As a result, minute substances such as dust are adsorbed on the surface of the dust adsorbing portion that is charged opposite to its own, before reaching the light passage surface of the speed measuring device or the optical system, and the light passage surface or It becomes difficult for dirt to adhere to the optical system. Claims 3 and 4
According to the configuration, when dirt adheres to the light passing surface of the speed measuring device, by exchanging the transparent adhesive seal or the transparent plate, the light from the speed measuring device passes through the light passing surface without being blocked, Received by the photodetector. According to the configurations of claims 5 and 6, since the ventilation device ventilates the light passage space from the ventilation system, dirt is prevented from adhering to the light passage portion of the device. Further, air is ventilated from the ventilation system, and the air is cleaned by the dustproof filter and ventilated to the light passage space.

According to the structure of claim 7, by changing the ventilation temperature in accordance with the temperature measured by the temperature sensor, the ambient temperature of the speed measuring device is kept within a certain range. According to the structure of claim 8, dirt is prevented from adhering to the optical system by the dirt preventing hood. Claims 9 and 10
According to this configuration, the water-repellent resin is used for the light passage surface, so that water droplets are less likely to adhere to the surface. In particular, since the transparent plate is inclined with respect to the horizontal plane, it becomes more difficult for water drops to adhere. According to the structure of claim 11, by controlling the brake or the accelerator by the output of this device, efficient braking or acceleration becomes possible. According to the structure of claim 12, efficient braking / accelerating ability can be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment embodying the present invention will be described below. FIG. 1 shows a schematic configuration of a spatial filter type velocity measuring device. The speed measuring device 1 is composed of a light source 3 that irradiates the road surface 2 with light, an optical system 4 that receives reflected light from the road surface 2, and a photodetector 5. The photodetector 5 detects the frequency signal, and the ground speed is calculated based on the frequency signal.

FIG. 2 shows a spatial filter type speed measuring device provided with an electrostatic type dust adsorbing device. The electrostatic dust attracting device 10 includes metal plates 11 and 12 facing each other and dielectric members 13 and 14 that support the metal plates 11 and 12, and the speed measuring device 1
It is arranged so as to surround a space (light passage space) through which reflected light from the road surface 2 of the light emitted from is passed. The metal plates 11 and 12 facing each other are arranged so as to face each other with the speed measuring device 1 interposed therebetween so as to have the same effect as that of the parallel plate capacitor.

In the above structure, the metal plate 11 is positively charged and the metal plate 12 is negatively charged, so that minute substances such as dust floating in the air are near the bottom surface of the velocity measuring device 1. Before reaching the light passage surface 6 or the optical system 4, it is adsorbed by the metal plate 11 or 12 which is charged opposite to its own charge. Therefore, the light passage surface 6 or the optical system 4 is not contaminated by dust or the like. Further, the vertical lengths of the metal plates 11 and 12 and the dielectric members 13 and 14 are set so that, for example, when the vehicle height becomes the lowest, the ends of each plate and each member are slightly higher than the road surface. By doing so, it is possible to prevent the adhesion of a relatively large mass such as mud, sand, and water droplets at a considerable rate. The opposing metal plates 11 and 12 are arranged so as to be parallel to the moving direction of the object to be measured, so that dust can be efficiently adsorbed.

Next, a second embodiment will be described. Figure 3
Shows an example in which a peelable transparent adhesive seal 22 is provided on the light passage surface 6 of the speed measuring device 1. Note that FIG. 3 is a view looking up from below, and the light passage surface 6 is parallel to the ground. Since the transparent adhesive sticker 22 can be peeled off, even when dirt adheres to the transparent adhesive sticker 22 and the reflected light from the road surface 2 is blocked, the adhered dirt is removed only by replacing the transparent adhesive sticker 22. be able to.

Next, a third embodiment will be described. Figure 4
Shows an example in which a removable transparent plate 23 is provided on the light passage surface 6 of the speed measuring device 1. Note that FIG. 4 is also a view looking up from below, and the light passage surface 6 is parallel to the ground.
The transparent plate 23 is attached to the frame of the light passing surface 6 by screwing unillustrated screws into the screw holes 24 at the four corners of the transparent plate 23 and the screw holes 25 of the frame of the light passing surface 6. Since the transparent plate 23 is detachable, even if dirt adheres to the transparent plate 23 and the reflected light from the road surface 2 is blocked, the adhered dirt can be removed only by replacing the transparent plate 23. .

As a modification of the second and third embodiments, when the transparent adhesive seal 22 or the transparent plate 23 provided on the light passage surface 6 is a water repellent resin, or the transparent adhesive seal 22 or the transparent plate 23 is used. The case where the water-repellent resin is applied or coated on will be described. In this case, even if a water drop contacts the transparent adhesive seal 22 or the transparent plate 23 for a moment, it will be repelled,
Water drops are less likely to adhere for a long time. Therefore,
The change in the optical path of the reflected light from the road surface 2 is reduced, and the deterioration of the measurement accuracy is reduced. Furthermore, the transparent plate 2
When 3 has an inclination with respect to the horizontal plane, it becomes more difficult for water droplets to adhere, so that the effect can be further enhanced. The water-repellent resin includes, for example, Teflon-based resin.

Next, a fourth embodiment will be described with reference to FIG.
In this embodiment, the anti-dirt hood 31 is attached to the spatial filter type speed measuring device 1. Dirt prevention hood 3
1 is provided so as to surround the speed measuring device 1 with a little space left between them. The tip of the lower portion of the dirt prevention hood 31 is formed so as to spread outward and the ventilation path 35 is provided in the upper portion of the dirt prevention hood 31.
The air passage 35 is provided with a dustproof filter 32 for cleaning the air that is ventilated. By a ventilation device (not shown), from an air conditioner ventilation system of the vehicle or a ventilation system provided independently of the air conditioner, through the dustproof filter 32 and through the gap between the dirt prevention hood 31 and the speed measuring device 1. An air flow A is formed in the light passage space of the velocity measuring device 1. By this ventilation, the light passing surface 6 can be stably prevented from being soiled without depending on the surrounding wind speed and vehicle speed, and even when the vehicle is stationary. Further, since the tip of the dirt prevention hood 31 has a divergent shape, the icicles 33 are separated from the light passage space even when the icicles 33 are generated in the speed measuring device 1, especially in cold regions. Since the reflected light from the road surface 2 does not pass through the central portion of the speed measuring device 1 and is not blocked by the icicles 33, it is possible to prevent problems such as a decrease in the amount of received light.

The speed measuring device 1 is provided with a temperature sensor 34, the temperature sensor 34 measures the temperature of the speed measuring device 1 or a specific portion of the vehicle, and the ventilation temperature of the ventilation device is changed according to this temperature. Thus, the ambient temperature of the speed measuring device 1 can be kept within a certain range. By doing so, the speed measuring device 1 is not subjected to stress due to excessive high temperature or low temperature, and the reliability of the speed measuring device 1 is improved.

An anti-lock brake system (ABS) for controlling the brake so as not to lock by using the output of the above spatial filter type speed measuring device 1.
Alternatively, a speed control system such as a traction control system (TCL) for controlling the accelerator can be constructed. Further, by mounting this speed control system on an automobile, efficient braking / accelerating ability can be obtained.

[0020]

As described above, according to the first and second aspects of the present invention, the electrostatic dust adsorbing device is provided so as to surround the light passage space of the optical system of the spatial filter type velocity measuring device. When the dust adsorption device is energized, dust is adsorbed to the dust adsorption part, and regardless of whether the vehicle is running or stopped, dirt does not adhere to the part through which the light passes and the light from the measurement target is blocked. Will disappear. As a result, the measurement accuracy becomes highly reliable. According to the invention of claim 3, since the transparent adhesive seal can be peeled off, when dirt adheres,
All that is required is to replace the transparent adhesive seal, which makes cleaning and maintenance of the light passage surface easy. According to the invention of claim 4, since the transparent plate is detachable, if the dirt adheres, the transparent plate only needs to be replaced, and cleaning and maintenance of the light passage surface can be facilitated. According to the invention of claim 5, since air is ventilated from the ventilation system to the light passage space,
Stable dirt can be prevented regardless of the surrounding wind speed and vehicle speed. According to the invention of claim 6, since the dustproof filter is provided in the ventilation passage from the ventilation system, clean air is constantly ventilated to the light passage space, and the portion where the light passes is prevented from being contaminated.

According to the seventh aspect of the present invention, in addition to the effect of preventing stains, the temperature sensor keeps the ambient temperature of the speed measuring device within a certain range, so that the speed measuring device is stressed by excessively high or low temperature. Is prevented from receiving
The measurement accuracy is highly reliable. According to the eighth aspect of the present invention, since the tip portion of the stain prevention hood has a divergent shape, the icicles are generated at the tip portion of the hood, especially in cold regions. Therefore, the detection light passing through the central portion of the hood is not blocked by the icicles, and a decrease in the amount of received light can be prevented. According to the invention of claim 9, since the light passage surface is made of a water-repellent resin, it becomes difficult for water droplets to adhere to the light passage surface, and therefore the change in the optical path of the light is small.
Measurement speed error is reduced. According to the invention of claim 10, since the transparent plate is inclined, it becomes difficult for water drops to adhere, which is useful for improving the measurement accuracy. According to the invention of claim 11, since an accurate speed measurement value can be obtained,
Efficient braking or accelerator control can now be performed, and braking distance can be shortened or good acceleration can be expected. According to the invention of claim 12, the braking distance is shortened,
Accelerates better and the safety of the car is higher.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a spatial filter type velocity measuring device.

FIG. 2 is a perspective view of a spatial filter type speed measuring device provided with an electrostatic type dust adsorbing device according to a first embodiment of the present invention.

FIG. 3 is a perspective view of a spatial filter type velocity measuring device provided with a transparent adhesive seal according to a second embodiment.

FIG. 4 is a perspective view of a spatial filter type velocity measuring device provided with a transparent plate according to a third embodiment.

FIG. 5 is a sectional view of a spatial filter type velocity measuring device provided with a stain prevention hood according to a fourth embodiment.

[Explanation of symbols]

 1 Spatial Filter Method Velocity Measuring Device 4 Optical System 5 Photo Detector 6 Light Passing Surface 10 Electrostatic Dust Adsorbing Device 11, 12 Metal Plate 13, 14 Dielectric Member 22 Transparent Adhesive Seal 23 Transparent Plate 31 Stain Prevention Hood 32 Dustproof Filter 34 Temperature sensor

Claims (12)

[Claims] 1. An optical system and a photodetector, which form a spatial filter for receiving light from a measurement target, and calculate the velocity of the measurement target based on a frequency signal detected by the photodetector. In the spatial filter type speed measuring device, an electrostatic type dust adsorbing device is arranged so as to surround the light passage space of the optical system. 2. The spatial filter type velocity measuring device according to claim 1, wherein a part of the surface of the dust adsorbing portion of the electrostatic dust adsorbing device is positively charged, and another part or all of the remaining part is negative. A spatial filter type velocity measuring device characterized in that it is electrically charged. 3. An optical system that constitutes a spatial filter for receiving light from a measurement target and a photodetector are provided, and the velocity of the measurement target is calculated based on the frequency signal detected by the photodetector. A spatial filter type velocity measuring device, wherein a transparent adhesive seal which can be peeled off is provided on a light passing surface of the spatial filter type velocity measuring device. 4. An optical system and a photodetector that form a spatial filter for receiving light from the measurement target, and calculate the velocity of the measurement target based on the frequency signal detected by the photodetector. The spatial filter type speed measuring device, wherein a transparent plate which can be freely attached and detached is provided on the light passage surface. 5. An optical system and a photodetector, which form a spatial filter for receiving light from the measurement target, are provided, and the velocity of the measurement target is calculated based on the frequency signal detected by the photodetector. A spatial filter type speed measuring device, characterized in that the spatial filter type speed measuring device is provided with a ventilation device for ventilating to a light passing space from an air conditioner ventilation system of a vehicle or a ventilation system provided independently of the air conditioner. . 6. The spatial filter type velocity measuring device according to claim 5, wherein a dustproof filter is provided in a ventilation passage from the ventilation system. 7. The spatial filter type velocity measuring device according to claim 5, further comprising a temperature sensor for measuring the temperature of the velocity measuring device or a specific portion of the vehicle, and the ventilation device ventilates according to the temperature measured by the temperature sensor. A spatial filter type velocity measuring device characterized in that the temperature is changed. 8. An optical system, which constitutes a spatial filter for receiving light from an object to be measured, and a photodetector, and calculates the velocity of the object to be measured based on a frequency signal detected by the photodetector. In the spatial filter type velocity measuring device, a stain preventing hood is arranged so as to surround the light passage space of the optical system, and the tip of the stain preventing hood is formed in a divergent shape. measuring device. 9. An optical system and a photodetector that form a spatial filter for receiving light from the measurement target, and calculate the velocity of the measurement target based on the frequency signal detected by the photodetector. In the spatial filter type velocity measuring device, a transparent plate or a transparent adhesive seal is provided on the light transmitting surface, and the transparent plate or the transparent adhesive seal is a water-repellent resin, or the transparent plate or the transparent adhesive seal has a water-repellent resin. A spatial filter type velocity measuring device characterized by being coated or coated with. 10. An optical system, which constitutes a spatial filter for receiving light from an object to be measured, and a photodetector, and calculates the velocity of the object to be measured based on a frequency signal detected by the photodetector. In the spatial filter type velocity measuring device, the transparent filter type velocity measuring device is characterized in that a transparent plate is provided on the light passage surface with an inclination with respect to the horizontal plane. 11. A speed control system comprising the spatial filter type speed measuring device according to claim 1, wherein the speed is controlled by controlling a brake or an accelerator according to the output of the device. 12. An automobile equipped with the speed control system according to claim 11.