JP2001074841A - Measuring apparatus for distance, moving speed, and moving direction utilizing laser light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily set a specified direction of irradiation with laser light and its scanning range, and to make an arithmetic CPU load small, and high in the measurement precision after photodetection. SOLUTION: An end part of the main shaft 25 of a swing motor 29 is connected and fixed to a reflecting mirror 13 through a fitting part 27. A reflector 5 is fitted to the rear part of a vehicle. Further, a photodetection part is arranged in the vicinity of the reflecting mirror 13. A scan with the reflected light from the reflecting mirror 13 is so made by specifying the angle of reflection in the reflecting mirror 13 or swing the reflecting mirror 13 so that the reflected light reaches the reflector 5. The CPU computes the distance between the photodetection part and reflection part on the basis of the time difference, phase difference, etc., between the laser light emitted by a laser light source 1 and the laser light detected by the photodetection part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
In connection with the moving speed and moving direction measuring device, in particular, it is possible to easily set the designated direction for irradiating the laser beam and the scanning range, and the load on the arithmetic CPU after receiving the light is small and the measuring distance and the moving speed of the laser beam are high. -It relates to a moving direction measuring device.

[0002]

2. Description of the Related Art Conventionally, when a distance between a vehicle and a preceding vehicle is measured using a laser beam, for example, the following method is used. 1. A reflector 5 attached to a rear portion of a vehicle 3 directly in front of a laser light source 1 from a laser light source 1 (the reflector 5 is usually provided at a rear portion of a car or a bicycle to diffusely reflect light from a rear vehicle). The light receiving unit 7
Receives the reflected light (not shown). Then, an inter-vehicle distance to the front vehicle 3 is calculated by calculation of a time difference, a phase difference, a Doppler effect, a frequency correlation and the like based on the irradiation light and the reflected light (not shown). 2. As shown in FIG. 2, a link mechanism 11 is attached to a driving unit 9 such as a DC motor or a stepping motor, and a reflecting mirror 13 is provided.
Rocks. As a result, the laser beam is scanned at a predetermined range angle, and the distance between the vehicle and the front vehicle 3 is calculated by calculation. 3. As shown in FIG. 3, a polygon mirror 17 is connected and fixed to the main shaft 15 of the drive unit 9. Then, the main shaft 15 is rotated in one direction. The polygon mirror 17 has a plurality of mirror surfaces 2 on the outer periphery.
0 is arranged. By rotating the mirror surface 20, scanning at a predetermined angle is performed.

[0003]

However, with respect to the above-mentioned method 1, there is a possibility that the laser light has high directivity, and if the vehicle in front moves left or right, detection becomes impossible. Further, in the case of the method 2, there is a possibility that the angular position accuracy at the time of swinging is deteriorated due to backlash or the like of the link mechanism 11. Since the link mechanism 11 is provided in addition to the drive section 9, the volume is increased. Further, the cost is increased by the cost of the link mechanism 11. Further, since the method 3 is constituted by a plurality of mirror surfaces 20, accuracy between the mirror surfaces is required. In addition, mirror surface 20
Are offset from the center of the spindle 15. And
This offset varies with the movement of the mirror surface 20. Therefore, a large amount of calculation is required to correct the reflected light, and the load on the calculation CPU is large. Since the arrangement angle of the mirror surface 20 from the center of the main shaft 15 is also fixed, the scan range cannot be changed. SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and can easily set a designated direction and a scanning range for irradiating a laser beam, and have a small load on an arithmetic CPU after light reception and a high measurement accuracy. It is an object of the present invention to provide a light utilization distance / movement speed / movement direction measurement device.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention provides a laser light source for irradiating a laser beam, and directs a laser beam received from the laser light source in a specified direction or scans a predetermined range angle around the specified direction. A first reflector to be adjusted, and an angle adjustment or / or an angle of the first reflector in the designated direction.
And a drive unit in which the end of the main shaft is fixedly connected to the first reflection unit for swinging the predetermined range angle, and the first reflection unit reflects the light in a designated direction or scans around the designated direction. A second reflecting portion for reflecting the laser light,
A light receiving unit that receives the laser light reflected by the second reflecting unit; and a light receiving unit and the second reflecting unit based on the laser light received by the light receiving unit and the laser light irradiated by the laser light source. An arithmetic unit is provided for calculating at least one of a distance, a moving speed of the second reflecting unit, and a moving direction of the second reflecting unit. Irradiate laser light from a laser light source. The laser light is reflected in the designated direction by the first reflecting section. Alternatively, scanning is performed at a predetermined range angle centered on the designated direction. The end of the main shaft of the drive unit is
Is connected and fixed to the reflection part. Then, by rotating the drive unit by a predetermined angle, an angle adjustment in a designated direction is performed,
Scanning is performed by swinging a predetermined range angle. The laser light emitted in this manner is reflected by the second reflector located at a remote position. Thereafter, the reflected light is received by the light receiving unit. The second reflector may be of any type as long as the light amount of the laser beam received by the light receiver is equal to or more than a predetermined value, and the structure of the reflection surface is not limited. Here, the predetermined value refers to a threshold value that can be calculated by the next calculation means based on the laser beam received by the light receiving unit. The calculating means determines a distance between the light receiving unit and the second reflecting unit based on a time difference, a phase difference, a wavelength difference, and the like between the irradiation light and the reflected light, and the second reflecting unit when the second reflecting unit moves. At least one of the moving speed and the moving direction of the second reflector is calculated. Accordingly, if the second reflecting portion exists in the scanned area, the light receiving portion and the second
Can be calculated. Further, since there is no link mechanism, it is possible to improve the angle adjustment accuracy and the resolution of the first reflecting section. Further, the reflected light is not offset, and the calculation of the reflected light can be easily performed, and the load on the calculation CPU is small. The scanning range and the designated direction can be set arbitrarily.

The driving unit is a DC motor or the like.
It is sufficient that the reflecting portion reflects the laser beam, and the reflecting portion can be constituted by a crystal or the like. Further, the second reflecting portion can be constituted by a mirror surface and can be not moved.
A swing motor that can control the rotation angle of the main shaft arbitrarily.
The first reflector may be a reflector for reflecting light, and the second reflector may be a reflector for reflecting or irregularly reflecting a predetermined amount of light, and the reflector may be provided in a vehicle. A swing motor is used for the drive unit. The oscillating motor can accurately control the rotation angle of the main shaft. The first reflecting section is configured by a reflecting mirror that reflects light, and the second reflecting section is intended for a reflector. The reflector is located on the vehicle. The irradiated laser beam is irregularly reflected, and a part of the laser beam reaches the light receiving unit. The laser light source, the reflecting mirror, the oscillating motor and the light receiving unit may be fixed, but may be mounted on another vehicle. At this time, by calculating the emitted laser light and the received laser light, it is possible to calculate the inter-vehicle distance to the preceding vehicle, the moving direction of the preceding vehicle, and the like.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1 showing an embodiment of the present invention, a swing motor 29 is capable of arbitrarily controlling the rotation angle of a main shaft 25. The end of the main shaft 25 is
3 is connected and fixed via an attachment portion 27. The reflector 5 is attached to a rear portion of the vehicle 3 (not shown). The light receiving unit 7 (not shown) is provided near the reflecting mirror 13. The laser light source 1, the reflecting mirror 13, the swing motor 29, and the light receiving unit 7 are mounted on a vehicle 33 (not shown). The reflected light from the reflecting mirror 13 is designed to scan the reflected light by specifying the reflection angle of the reflecting mirror 13 or swinging the reflecting mirror 13 so as to reach the reflector 5.

Next, the operation will be described. The end of the main shaft 25 of the oscillating motor 29 is connected and fixed to the reflecting mirror 13 via a mounting portion 27. Therefore, the reflecting mirror 13 follows the movement of the main shaft 25. The laser light emitted from the laser light source 1 is emitted toward the central portion of the reflecting mirror 13 or an extension of the center of the main shaft 25. The laser light is reflected by the reflecting mirror 13 and irradiated in a designated direction. If the position of the reflector 5, that is, the position of the vehicle 3 is fixed, the laser beam is reflected by the reflector 5 by irradiating in the designated direction. However, when the position of the reflector 5 is unknown, the main shaft 25 of the swing motor 29 is swung, and the reflecting mirror 13 is swung by a predetermined angle, so that the laser beam reflected by the reflector 5 is detected by the light receiving unit 7 (not shown). I do. If the laser light detected by the light receiving unit 7 is subjected to arithmetic correction of the distance and the angle, the light receiving unit 7 can be disposed at, for example, the vicinity of the laser light source 1 or any other location. It is possible. The CPU calculates the distance between the light receiving unit 7 and the reflector 5 based on the time difference, phase difference, wavelength difference, and the like between the laser light emitted from the laser light source 1 and the laser light received by the light receiving unit 7. As a result, if the reflector 5 exists in the scanned area, the distance between the light receiving unit 7 and the reflector 5, the moving speed of the preceding vehicle, the moving direction of the preceding vehicle, and the like can be calculated. Further, since there is no link mechanism, the angle adjustment accuracy and resolution of the reflecting mirror 13 can be improved. Further, the reflected light is not offset, and the calculation of the reflected light can be easily performed, and the load on the calculation CPU is small. The scanning range of laser beam irradiation and the designated direction can be set arbitrarily. The reflecting mirror 1
Numeral 3 may change a light beam such as a crystal to a polarizable one. Further, the laser light source 1 may be directly mounted on the mounting portion 27 instead of the reflecting mirror 13.

[0008]

As described above, according to the present invention, since the end of the main shaft of the drive section is connected and fixed to the first reflection section, the designated direction for irradiating the laser beam and the scanning range can be changed. It can be easily set, and the load on the arithmetic CPU after light reception can be reduced, and the measurement accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a conventional inter-vehicle distance measuring apparatus using laser light.

FIG. 3 is a schematic configuration diagram of another conventional inter-vehicle distance measuring apparatus using a laser beam.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser light source 3, 33 vehicle 5 reflector 7 light receiving unit 13 reflecting mirror 25 main shaft 29 swing motor

Claims (2)

[Claims] 1. A laser light source for irradiating a laser beam, a reflecting mirror for reflecting a laser beam received from the laser light source, a mirror surface of the reflecting mirror swinging, and an end of a main shaft connected to the reflecting mirror. A fixed rocking motor, a reflector that reflects laser light scanned around a designated direction by the reflector, a light receiving unit that receives the laser light reflected from the reflector, and a laser that is received by the light receiving unit A laser including at least one of a calculating unit that calculates at least one of a distance between a light receiving unit and the reflector, a moving speed of the reflector, and a moving direction of the reflector based on light and a laser beam irradiated by the laser light source. In the light utilization distance / movement speed / movement direction measurement device, the rocking motor may be configured such that the mirror surface of the reflection mirror is centered on an arbitrary designated direction and responds to an input signal. The relationship between the output angles is linearly swingable in equal directions in the positive direction and the negative direction, and the reflector reflects the laser light by irregular reflection. measuring device. 2. A laser light source for irradiating a laser beam in a specified direction, a rocking motor for oscillating the laser light source and an end of a main shaft connected to and fixed to the laser light source, and a laser light source specified by the laser light source. A reflector that reflects the laser light scanned around the direction, a light receiving unit that receives the laser light reflected by the reflector, a laser light that is received by the light receiving unit, and a laser light that is irradiated by the laser light source. Calculating means for calculating at least one of the distance between the light receiving unit and the reflector, the moving speed of the reflector, and the moving direction of the reflector. The rocking motor is arranged such that the laser light source is centered on an arbitrary designated direction, and the relationship of the output angle with respect to the input signal is linearly positive. And a reflector that reflects the laser light by irregular reflection, wherein the reflector reflects the laser light by irregular reflection.