JPH0473082B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a method for determining whether the distance to the object to be measured is larger or smaller than the reference distance when the distance to the object to be measured is compared with a predetermined reference distance. This invention relates to a distance sensor that optically detects distance.

[Prior Art] Conventionally, as this type of device, one using ultrasonic waves as shown in FIG. 1, for example, is known. This device consists of an ultrasonic transmitter 1 and an _ultrasonic receiver 3 installed at a predetermined distance from the ultrasonic transmitter 1.
The reflected wave is received by the ultrasonic receiver 3, and the distance lt at that time is determined by the following formula by measuring the time t _d from the reflection of the pulse wave to the reception. .

l _t = a・t _d /2 …(1) where a is the speed of sound, lt >> ls In this way, as shown in Fig. 2, an ultrasonic transmitter 1 and an ultrasonic receiver 3 are constructed. The sensor unit 4 is attached to a moving object 5 moving in the direction of the arrow on the illustrated x-axis at a constant distance w from the x-axis, and the distance h between the sensor unit 4 and the object to be measured 2' is determined by the above (1). ) was used to determine the distance h between the moving object 5 and the portion to be measured 2'. The magnitude relationship between the distance to the object to be measured 2' and a predetermined reference distance can be detected from the sign of (h+w-d). That is, when (h+w-d)>0, the distance (h+w) to the object to be measured 2' is greater than the reference distance d, and when (h+w-d)=0, the distance to the object to be measured 2' Distance to ′ (h+w)
is equal to the reference distance d, and (h+w−d)<
If 0, the distance to the object to be measured 2' (h+w)
becomes smaller than the reference distance d.

In the distance sensor configured as described above,
The transmission and reception time is measured using ultrasonic waves, and various calculation processes are performed based on the ultrasonic waves.
However, since the speed of sound changes due to the influence of natural phenomena such as temperature and wind, errors tend to occur in the distance h to the object to be measured 2'. When the relationship between two distances is particularly small, it is difficult to accurately detect it. Furthermore, since the magnitude relationship is detected by comparing two distances as described above, there is an inconvenience that it takes time to determine the magnitude relationship.

[Summary of the Invention] The present invention has been made to eliminate the drawbacks of the conventional devices as described above. In a distance sensor that detects a magnitude relationship between a measured distance between the moving measuring section and the object to be measured and a plurality of preset reference distances in a direction perpendicular to the traveling direction of the moving measuring section, a light source is provided. and a light receiving section that receives the light emitted from the light source section and reflected by the object to be measured, at a position where the light emitted from the light source section corresponds to the plurality of reference distances. A plurality of units are provided in the movable measurement unit so as to intersect with each other, and when the movable measurement unit moves in the vicinity of the object to be measured in a predetermined direction, the light receiving order of the plurality of observation units with respect to the traveling direction of the movable measurement unit is determined. The object of the present invention is to provide a distance sensor capable of detecting the magnitude relationship between the plurality of set reference distances and the measurement distance, and quickly and accurately determining the magnitude relationship between the two distances.

[Embodiments of the Invention] The present invention will be described below with reference to the illustrated embodiments. In FIG. A hood 9 is attached to this observation section except for the part in the irradiation direction, and this hood 9 blocks out disturbance light. As shown in FIG. 4, this observation section consists of an x
They are provided on the side portion 10a parallel to the axis, at a predetermined distance l, on the moving direction side and on the opposite side of the moving direction. The first observation unit 11 on the side in the moving direction is tilted at a predetermined angle θ ₁ with respect to the x-axis, and the second observation unit 1 on the opposite side in the moving direction
2 is tilted at a predetermined angle θ ₂ with respect to the x-axis, and these first and second
The irradiated light beams from the light sources of the observation units 11 and 12 are set to intersect at a point p at a predetermined reference distance d from the x-axis. Note that t _a and t _d indicate target detection directions of the first and second observation units 11 and 12.

In the distance sensor according to the above configuration, the first,
Intersection p of the target detection directions of the second observation units 11 and 12
The distance h between and the side portion 10a of the movement measurement unit 10 is obtained from the following equation.

h=l・sinθ ₁・sinθ ₂ /sin(θ ₁ −θ ₂ )...(2) Then, the reference distance d, which is the distance between the above-mentioned intersection p and the x-axis, is determined by the first and second observation units 11 and 12. The angle formed with the When the distance to the object to be measured 13 (hereinafter referred to as the actual distance) is larger than the reference distance d (as in the case of FIG. 4), the second measuring section 1
The second irradiation light beam is reflected by the object to be measured 13, and the reflected light is received by the light receiving element 8 of the second observation section 12. Thereafter, in the same manner as above, the first measuring section 11
detects the object to be measured 13. Next, when the actual distance is smaller than the reference distance d, contrary to the above case, the first observation section 11 detects the object to be measured 13, and then the second observation section 12 detects the object to be measured 13. Object 13 will be detected.

In this way, the moving measuring section 10 is moved,
Depending on which of the first and second observation sections 11 and 12 receives the reflected light from the object to be measured 13 first, it is possible to accurately detect the magnitude relationship between the actual distance and the reference distance.

A distance sensor configured in this way is installed, for example, on an automatic guided vehicle in a factory, and is set so that the allowable passing width of the guided vehicle is the reference distance, and the distance between the guided vehicle and a wall, etc. is set to the reference distance. It is possible to detect whether the vehicle is large or small and operate the automated guided vehicle smoothly.

In the above embodiment, the movable measurement unit was provided with two observation units, but if more observation units are attached to provide multiple intersections of the irradiated light, it will be possible to determine not only the size relationship but also the actual distance. It is also possible to detect the range. For example, as shown in FIG. 5, a third observation section 14 is provided, and the intersections p, p ₁
When the movable measurement unit is moved in the direction of the arrow, the reflected light from the object 15 is at the 314th, 111th, and 2nd points when the object 15 is at the position shown in the figure.
The observation unit receives the light in the order of 12, and the object to be measured 15
can be detected to be located between two reference distances h and _h1 .

[Effects of the Invention] As described above, according to the present invention, when the moving measuring section is mounted on a moving measuring section and the moving measuring section moves in the vicinity of the object to be measured in a predetermined direction, the moving measuring section and the object to be measured are connected to each other. A distance sensor that detects a magnitude relationship between a measured distance between a light source and a plurality of reference distances set in advance in a direction perpendicular to the traveling direction of the moving measuring section, the light source section and the object to be measured that is emitted from the light source section. A plurality of observation sections each having a light receiving section that receives light reflected by an object are attached to the movable measuring section so that the light emitted from the light source section intersects at a position corresponding to the plurality of set reference distances. and when the movable measurement section moves in the vicinity of the object to be measured in a predetermined direction, the plurality of reference distances and the measurement distance are determined according to the light receiving order of the observation section with respect to the traveling direction of the movable measurement section. Since the distance sensor detects the magnitude relationship between

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional distance sensor, FIG. 2 is a diagram of a measurement example using the sensor of FIG. 1, and FIG. 3 is a block diagram of a distance sensor showing an embodiment of the present invention.
FIG. 4 is a diagram of a measurement example using the sensor shown in FIG. 3, and FIG. 5 is a diagram of a measurement example showing another embodiment according to the present invention. 6: light source, 8: light receiving element, 11, 12, 14:
Observation section, 5, 10: Mobile measurement section.

Claims (1)

[Claims] 1 mounted on a moving measuring section, and when the moving measuring section moves in the vicinity of the object to be measured in a predetermined direction, the measured distance between the moving measuring section and the object to be measured and the progress of the moving measuring section A distance sensor that detects a magnitude relationship with a plurality of preset reference distances in a direction orthogonal to a direction, comprising a light source section and a light receiving section that receives light emitted from the light source section and reflected by the object to be measured. A plurality of observation sections are provided in the movable measuring section so that the light emitted from the light source section intersects at positions corresponding to the plurality of reference distances, and the movable measuring section observes the vicinity of the object to be measured. When traveling in a predetermined direction, a magnitude relationship between the plurality of set reference distances and the measurement distance is detected based on the order in which the plurality of observation units receive light with respect to the traveling direction of the moving measurement unit. sensor.