JPH0479401B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a distance measuring method for a moving object, and particularly to a distance measuring method for a moving object using a light beam.

<Prior Art> When a moving object is automatically guided from a fixed base point, it is necessary to measure the distance of the moving object from the base point. Various methods using light beams have been proposed as distance measuring methods for moving objects.

<Problems to be Solved by the Invention> However, conventional distance measuring methods generally have the drawback of being complicated.

The present invention was created in view of the above points,
It is an object of the present invention to provide a method for measuring the distance of a moving object using a light beam, which allows the distance of the moving object from a base point to be measured relatively easily.

<Means for Solving the Problems> The method for measuring the distance of a moving object using a light beam according to the present invention includes a method for measuring the distance of a moving object using a light beam according to the present invention. A light beam rotation radiating means is provided for rotating and radiating a light beam on the same plane in parallel at a constant angular velocity about the base point, while a light beam for detecting the two rotationally radiated light beams is provided on the moving body. It is equipped with a sensor and a time interval measurement circuit that measures the time interval between receiving two light beams based on the output of the optical sensor. By measuring the time interval t of receiving the beam, the distance l from the base point to the moving body is calculated as follows: l=a/ωt, where a: distance between light sources Q ₁ and Q ₂ ω: angular velocity of the light beam t: time It is calculated based on the interval.

<Example> Hereinafter, an example according to the present invention will be described with reference to the drawings.

Fig. 1 is a schematic diagram illustrating the light beam rotation radiation means provided on the stationary side, Fig. 2 is a plan view illustrating the optical sensor provided on the movable body, and Fig. 3 A is a schematic diagram illustrating the optical sensor disposed on the movable body. FIG. 3(b) is a block diagram of the time interval measuring circuit shown in FIG.

In FIG. 1, reference numeral 1 denotes an object that is provided on the fixed side and rotates at a constant angular velocity ω around a base point O by a drive device (not shown). Q ₁ and Q ₂ are light sources respectively provided at symmetrical positions spaced apart by a predetermined distance in the radial direction from the base point O, and are adapted to emit light beams L ₁ and L ₂ .

The object 1 and the two light sources Q ₁ and Q ₂ constitute a light beam rotation radiating means.
The light beams L ₁ and L ₂ are emitted so as to rotate in parallel on the same plane at a constant angular velocity ω about the base point O.

On the other hand, an optical sensor 5 is provided at an arbitrary point S of the moving body on the plane so that the light beams L ₁ and L ₂ are incident thereon.

The distance between the base point O and the point S (hereinafter referred to as the "distance of the moving object")
) is l, and the distance between the light sources Q ₁ and Q ₂ , that is, the interval between the light beams L ₁ and L ₂ (hereinafter referred to as "beam width") is a.

When the beam width a is sufficiently smaller than the distance l of the moving object, the time interval t between the two light beams L ₁ and L ₂ received by the optical sensor 5 is determined from t=a/ωl. Therefore, the distance l of the moving object can be calculated from l=a/ωt (1).

On the other hand, the optical sensor 5 attached to the moving object is
As shown in FIG. 2, a photocell 52 consists of two photodiodes 51a and 51b arranged in parallel.
It is formed by connecting three. In this embodiment, the photodiode 51a is used to receive a light beam, and the other photodiode 51b is used to remove the influence of ambient light.

Therefore, when the light beams L ₁ and L ₂ cross the optical sensor 5, two pulses are generated after a certain period of time, and the time interval between the pulses is measured by a time interval measuring circuit, which will be described later.

As shown in Figure 3A, the time interval measurement circuit is
It includes an optical sensor 5, a waveform shaping circuit 6, a counter control circuit 7, a counting circuit 8, a clock oscillation circuit 9, and a microcomputer 10.

The two pulses output from the optical sensor 5 are given to the waveform shaping circuit 6, which converts them into a TTL level signal S ₁
After being formatted as follows, it is applied to the counter control circuit 7. The counter control circuit 7 generates a start/stop signal _S2 for the count circuit 8 from the signal _S1 , and supplies this as one input to the count circuit 8. On the other hand, since the clock pulse _S3 is supplied from the clock oscillation circuit 9 as the other input of the counting circuit 8, the counting circuit 8 counts clock pulses according to the time difference between the two pulses output from the optical sensor 5. Then, this count output is given to the microcomputer 10, and the time interval t
is calculated, and furthermore, the distance of the moving object is determined based on the above-mentioned arithmetic expression. For example, the calculation result is
displayed on the LED display.

<Effects of the Invention> As explained above, the present invention measures the time interval at which a moving body receives two parallel light beams,
By substituting this time interval into a simple arithmetic expression, the distance of the moving object is calculated.
Compared to conventional measurement methods, this method is very convenient because it allows you to easily measure the distance of a moving object.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram illustrating the light beam rotation radiation means provided on the stationary side, Fig. 2 is a plan view illustrating the optical sensor provided on the movable body, and Fig. 3 A is a schematic diagram illustrating the optical sensor disposed on the movable body. FIG. 3(b) is a block diagram of the time interval measuring circuit shown in FIG. 1...Object, 5...Photo sensor, _L1 , _L2 ...Light beam, _Q1 , _Q2 ...Light source.

Claims (1)

[Claims] 1. On the fixed side, each light beam emitted from two light sources provided at symmetrical positions separated by a predetermined distance from a base point is rotated in parallel on the same plane at a constant angular velocity around the base point. The moving body is equipped with a rotating light beam emitting means for emitting the rotating light beam, and the moving body is equipped with a light sensor for detecting the two light beams that are rotated and emitted, and a timer for receiving the two light beams based on the output of the light sensor. and a time interval measuring circuit for measuring the interval, detecting the two light beams, and measuring the time interval t between receiving each light beam with the time interval measuring circuit, from the base point to the moving object. The distance l of the light beam is calculated as follows: l=a/ωt, where a: distance between light sources Q ₁ and Q ₂ ω: angular velocity of the light beam t: time interval. Distance measurement method.