JP3297306B2 - Position detection 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 position detecting device which is applied to a moving body such as an elevator and detects a moving amount.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing an encoder pattern used in a conventional position detecting device, FIG. 6 is a diagram showing the entire structure of a conventional position detecting device, and FIG. 7 is a diagram showing the structure of another conventional type of position detecting device. It is. In these figures, reference numeral 1 denotes a moving object, on which optical sensors 3, 4 and a light source 7 are provided. Reference numeral 22 denotes an encoder pattern, which is fixed to a wall or the like and has black and white stripes, that is,
A light portion 11 and a dark portion 12 are provided.

As shown in these figures, as a method of detecting the moving amount of the moving object 1, there is a method of counting the change of the encoder pattern 22 between black and white or light and dark, and detecting the moving amount from the change amount. In this method, it is necessary to prepare an encoder pattern 22 having black and white or stripes of bright and dark portions 11 and 12.

In order to detect black and white or light and dark of the encoder pattern 22, the projection light 5 from the light source 7 is applied to the encoder pattern 22. At that time, utilizing the fact that light is reflected in the bright portion 11 and light is not reflected in the dark portion 12 of the encoder pattern 22, the change in the reflected light 6 is captured by the optical sensors 3 and 4, and the portion where the light is reflected is The voltage is high, and the portion where there is no light reflection is converted into an electric signal such that the voltage is low. Further, the change in the electric signal is changed by the waveform shaping circuit 8 of FIG. By using a digital signal so as to obtain, for example, when it is 1, it is counted by the counter 9 and 0
In the case of, the counter circuit does not count, and the amount of movement of the object is detected based on the value.

In order to know the direction in which the object moves, the phase difference of the detection output of the encoder pattern 22 needs to be 90 °. As shown in FIG. Is 90 °, or the outputs of the optical sensors 3 and 4 are 90 ° as shown in FIG.
The encoder pattern 22 is attached so as to have a phase difference of

There are two types of outputs of the optical sensor.
Assuming that one of the two optical sensors is 3 and the other is 4, the moving direction can be known depending on which optical sensor outputs first. For example, by counting up the counter when the optical sensor 3 outputs first, and counting down the counter when 4 is detected first, it is possible to capture the direction and location in which the object has moved. The moving amount of the object is detected by the above method.

[0007]

In the light and dark encoder pattern 22 such as black and white or the like, the width ratio between the light portion 11 and the dark portion 12 of the encoder pattern 22 is set as follows:
b. Here, as a conventional problem, when a = b, when the detection level L is set as shown in FIG. 8B due to a reaction delay of the sensor, etc., after the detection signal waveform is shaped, In some cases, the width c <d as shown in FIG.

Further, if the speed of the moving object 1 is too high, there is a problem that c eventually disappears and is not counted. Therefore, reduce the speed of the moving object,
It was necessary to increase the width of the encoder pattern.

[0009]

According to the present invention, in order to solve the above-mentioned problems, bright and dark stripes are alternately arranged in a straight line, and the stripes are arranged in accordance with the moving speed of a moving body passing the front surface thereof. high-speed range the linear direction, mid-speed range, provided with a speed range that is divided into the low speed range, in each speed range, the width a and the dark of the width of the bright portion
The ratio of b is a: b = 2: 1 in the high speed range, and
a: b = 3: 2, a: b = 1: 1 in the low speed range
Passage determined by a / (speed of each speed range)
An encoder pattern arranged to set the width a of the bright portion so that the time is constant ; an optical sensor attached to the moving body and reading the bright and dark portions of the encoder pattern; And a detecting unit for shaping and detecting the waveform.

According to the present invention, the ratio of the width (a) of the width of the bright portion to the dark portion of the encoder pattern 22 having light and dark portions such as black and white is determined by such means in accordance with the moving speed at which the moving body normally passes through the position. : B) With respect to the encoder pattern obtained by changing stepwise, the light / dark pattern is read by an optical sensor attached to the moving body, the signal is counted by a counter of a detection unit, and the counted signal is detected by waveform shaping. The movement amount is detected based on the count. The moving direction of the moving body can be known, for example, by arranging two optical sensors and detecting the output from one of the optical sensors first.

In the conventional method, as shown in FIG.
The black-and-white or bright / dark encoder pattern 2 may not be counted depending on the speed of the moving object 1 due to a sensor response delay or the like. By changing stepwise, the detection of the signal by the reflected light from the bright portion can be ensured, and the duty ratio of the output signal by the waveform shaping circuit after it is actually detected by the sensor can be made approximately 50%. . In practice, the speed of the moving object changes continuously,
The encoder pattern changes stepwise (discontinuously). Therefore, it is preferable to increase the number of stages of the change of the encoder pattern as much as possible to suppress the discontinuity within a range where no influence is exerted.

[0012]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a position detection device according to an embodiment of the present invention. In FIG. 1, 1 is a moving object, 2 is an encoder pattern, 3 and 4 are optical sensors, 7 is a light source, 5 is projection light, and 6 is reflected light. Numeral 11 denotes a bright portion of the black and white stripes of the encoder pattern 2, and numeral 12 denotes a dark portion, the widths of which are a and b, respectively.

[0013] As shown in FIG.
Are black and white or light and dark stripes. The light source 7 emits light using visible light, laser light, or the like. Further, the encoder pattern 2 is mounted on a fixed side such as a wall. The moving object 1 performs an operation in which the range of the approximate moving speed is limited for each encoder pattern position.

The encoder pattern 2 is divided into a high-speed area, a medium-speed area and a low-speed area according to the moving speed of the moving object 1 as shown in the figure.
The ratio is changed stepwise as a: b = 2: 1, a: b = 3: 2 in the medium speed range, and a: b = 1: 1 in the low speed range. It is configured not to happen. Further, as described later, the duty ratio of the output signal from the waveform shaping circuit can be set to approximately 50%.

As described above, in the example of FIG. 1, the speed pattern of the encoder pattern 2 is divided into three stages. However, since the actual speed of the moving object 1 changes continuously, the speed is set so as to follow the speed of the moving object 1. It is preferable to increase the number of steps of pattern 2 as much as possible so as not to affect the discontinuity.

FIG. 2 is a circuit configuration diagram of the position detecting device according to the above embodiment. This device includes optical sensors 3 and 4, a waveform shaping circuit 8, a counter 9, and a value output 10. The optical sensors 3 and 4 are mounted in a moving object. For example, the voltage is high when light is received, and the voltage is low when light is not received. Thus, the encoder pattern 2 is detected.

This signal is converted by the waveform shaping circuit 8 into a digital signal such as 1 when the voltage is high and 0 when the voltage is low. By reading this digital signal with the counter 9, the position of the moving object 1 is detected, and this position is output from the value output 10.

FIG. 3 is a diagram showing the relationship between the speed of the moving object 1 and the encoder pattern 2 in the position detecting device according to the present embodiment. As shown in FIG. 3, the speed at which the moving object 1 passes on each encoder pattern 2 is represented by v _X (x = 1, 2, 3,...)
, The length of a _x of the encoder pattern, the time for moving object 1 passes over each pattern and t _x.

If a _x is constant, the transit time t _x
It is depending on the speed v _X on each encoder pattern, which becomes the difference between the duty ratio of the waveform shaping circuit 8. Therefore, in advance, it is possible to eliminate _{a x / v X = t x} = little difference in duty ratio due to the moving speed of the moving object if installed certain to become such a _x. further,
The duty ratio in the waveform shaping circuit 1 is 50% (c = d)
Setting the a _x so that it is possible.

FIG. 4 is a diagram showing an optical sensor signal output of the position detecting device according to the present embodiment. The optical sensor is mounted so that the detection output phase is shifted by 90 °. That is, two types of optical sensor outputs are conceivable as shown in (a) and (b).

When one of the two sensors is the optical sensor 3 and the other is the optical sensor 4, the direction of movement can be known depending on which optical sensor is detected first.
For example, since in the case of FIG. 4 (a) is an optical sensor 3 is output first, the counter 9 and the count-up, 4
In the case of (b), since the optical sensor 4 is detected first, the countdown is performed, and it is possible to grasp the moving direction and location.

In a case where a moving object moves at a low speed in an area that should move at a high speed, the duty ratio is set to 50.
%, But there is no possibility that the count of the encoder pattern 2 is missed. For certainty, in such an emergency, the moving object is returned to the initial position at a low speed and the counter 9 is cleared.

[0023]

As described above in detail, according to the present invention, an encoder pattern in which bright portions and dark portions are alternately arranged is provided with a stepwise speed range, and a bright portion and a dark portion in this speed range are provided. The width ratio is gradually changed from the low-speed region to the high-speed region, and the configuration is provided with an optical sensor that reads the bright and dark portions, and a detection portion that detects the read signal. It has such effects.

In the conventional method, when the speed of the moving object increases, the output of the sensor becomes bright portion (c) <dark portion (d) or c =
When it becomes 0, the position detection may be unstable or may include an error. However, in the present invention, since the encoder pattern according to the moving speed of the moving body is used, the output of the waveform shaping circuit can be substantially set to c = d, and the counter can reliably count. This makes it possible to eliminate a position detection error.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a position detection device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a circuit of the position detection device according to one embodiment of the present invention.

3A and 3B are diagrams illustrating a relationship between a speed of a moving object and an encoder pattern at each position of the position detection device according to the embodiment of the present invention, wherein FIG.
(B) shows the waveform of the waveform shaping circuit.

FIG. 4 is a diagram of an optical sensor signal output of the position detection device according to the embodiment of the present invention, showing two types of outputs whose positions are shifted between (a) and (b).

FIG. 5 is a diagram showing an encoder pattern of a conventional position detecting device.

FIG. 6 is an overall configuration diagram of an example of a conventional position detection device.

FIG. 7 is an overall configuration diagram showing another example of a conventional position detection device.

8A and 8B are diagrams showing the influence of a conventional encoder pattern and a reaction delay of a sensor, wherein FIG.
(B) shows the output of the optical sensor, and (c) shows the output of the waveform shaping circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Moving object 2 Encoder pattern 3 Optical sensor 4 Optical sensor 5 Projection light 6 Reflection light 7 Light source 8 Waveform shaping circuit 9 Counter 10 Value output 11 Bright part 12 Dark part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-51020 (JP, A) JP-A-56-14112 (JP, A) JP-A-2-555 (JP, A) 31127 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00 G01D 5/30

Claims (1)

(57) [Claims] 1. A speed in which bright and dark stripes are alternately arranged in a straight line, and the linear direction is divided into a high speed region, a medium speed region, and a low speed region according to the moving speed of a moving object passing through the front surface. Area, and in each speed area, the width a of the bright part and the width of the dark part
The ratio of b is a: b = 2: 1 in the high speed range, and
a: b = 3: 2, a: b = 1: 1 in the low speed range
Passage determined by a / (speed of each speed range)
An encoder pattern arranged to set the width a of the bright portion so that the time is constant ; an optical sensor attached to the moving body and reading bright and dark portions of the encoder pattern; and counting the signals of the optical sensor. A position detection device comprising: a detection unit for performing waveform shaping and detecting the waveform.