JP2019190861A - Detection device - Google Patents

Abstract

To prevent non-operation under noise environments in a detection device configured by a projector, a light receiver, and a controller.SOLUTION: A detection device configured by a projector, a light receiver, and a controller is for: causing the controller to store, as a light reception signal R1, a light reception amount of the light receiver while light is not emitted by the projector; causing the controller to store, as a light reception signal R2, a light reception amount of the light receiver while the light is emitted by the projector; obtaining a threshold 2 by adding a value corresponding to the light reception signal R1 to a preset threshold 1; comparing the threshold 2 with the light reception signal R2; and then outputting a detection signal when the light reception signal R2 is smaller than the other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a detection device including a projector, a light receiver, and a controller, and particularly to prevention of malfunction in a noisy environment.

  Conventional detection devices of this type used for the purpose of detecting intruders and starting the device include a projector that projects a light projection signal received from a controller as a light beam, and a light beam that is received and controlled as a light reception signal. A receiver that transmits to the projector, and a controller that transmits the projection signal to the projector and receives the received signal from the receiver. The projector and the receiver are opposed to each other with a detection interval, and the optical axes are aligned. There is a form of installation. A detection operation is performed by detecting that a light beam projected from the projector is blocked by a person or an object passing through the detection section and does not reach the light receiver.

  In this type of detector, infrared rays, ultraviolet rays, and visible rays can be used as light rays. Moreover, infrared rays are generally used as a detection device for crime prevention or industrial use.

  The optical axis in the present invention refers to the central axis of the light output characteristics of the projector and the central axis of the light input characteristics of the light receiver. Further, making the optical axes coincide with each other so that the central axes of these characteristics overlap each other.

  Due to the influence of disturbance light and electromagnetic noise (hereinafter these two are collectively referred to as noise etc.), even if the light beam is blocked by blocking between the projector and the receiver, the detection operation may not be performed. It is called non-operation, and there are cases where the detection operation is performed even if the projector and the light receiver are not cut off, and this is called a malfunction.

  Disturbance light includes fluorescent light, alternating light that periodically blinks, and direct-current light that continues a substantially constant amount of light, such as sunlight, and is input to the controller via a light receiver.

  Electromagnetic noise originates from the motor of the automatic door and is input to the controller via the power supply wiring, etc., or radio waves pass through the power supply wiring, between the projector and the controller, or between the receiver and the controller. May be input to the controller. Those derived from an electromagnetic relay or the like generate electromagnetic noise only at the time of switching, while those derived from a motor such as an automatic door continuously generate electromagnetic noise during operation of the motor.

  In general, in this type of detection device, at the time of installation, the amount of light to be projected is set by adjusting the power supplied to the projector, or the threshold value for determining the presence or absence of interruption in consideration of the installation environment is set to an appropriate value. . For example, in an environment with a lot of noise, increase the power supplied to the projector or set the threshold higher than normal so that the projector does not malfunction due to noise, etc. Discriminates between optical signals and noise.

  Conventionally, there has been an improvement in the circuit of a light receiver so that normal operation continues even when the light receiver receives disturbance light (for example, Patent Document 1). Further, as in Patent Document 2, there is a technique that avoids the influence of disturbance light by changing the light projection period when receiving noise or the like. As a result, it is possible to prevent malfunctions and malfunctions caused by electromagnetic noise originating from electromagnetic relays, noise such as momentary light, disturbance light that repeats blinking periodically, and noise input at a certain period. .

  Further, in Patent Document 3, the influence of noise or the like is avoided by moving the threshold according to the amount of noise under the influence of noise or the like. It is necessary to set the average amount of received light (alignment tuning), and cannot be used when the position through which the target detection object has not been determined.

Japanese Utility Model Publication No. 6-34713 JP 2017-158177 A Japanese Patent No. 5128329

  In the conventional method of changing the light projection period described above, if noise or the like is continuously input, even if the light projection and light reception periods are changed, the noise will be present in the same manner, and the operation may be disabled. There is a problem that the position through which the detection object passes needs to be determined in advance.

  The above-mentioned noise is not necessarily generated at the time of installation. If a large amount of light is set in advance at the time of installation, the power consumption is unnecessarily increased, and if the threshold value for detection and handling is set high, the detection section is shortened. There was a problem that.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems, and to provide a detection device that does not operate even if noise or the like is continuously input and that causes little increase in power consumption.

  In order to achieve the above object, the present invention takes the following technical means. The amount of light received by the light receiver when the light projector is not projecting light is stored in the controller as a light reception signal R1, and the amount of light received by the light receiver when the light projector is projecting light is used as the light reception signal R2. The threshold value 2 is obtained by adding a value corresponding to the light reception signal R1 to the preset threshold value 1, and the threshold value 2 and the light reception signal R2 are compared. If the light reception signal R2 is smaller, the detection signal is output. The detection device to be used.

  In addition, the light reception signal R1 is stored in the controller after the light emission from the light projector is completed and after the time required for discharging the capacitor of the light receiving circuit in the light receiver stored in the controller in advance until the light projection starts. It is preferable to make it.

  In addition, the light receiver may set an average of the light reception signal received at the midpoint immediately after the light projector emits light and at the midpoint immediately before the light projection next to the light reception signal immediately before the light projector emits as the light reception signal R1. preferable.

  The controller preferably corrects the magnitude of the light projection signal in accordance with the magnitude of the light reception signal R1.

Since the magnitude of the threshold 2 changes according to the magnitude of noise or the like, there is an effect that the detection device is less likely to be inoperative.
In addition, if the threshold value 2 is increased, a sufficient amount of received light may not be obtained depending on the detection distance and the environment, and a malfunction may occur. However, the controller increases the amount of light emitted according to the size of noise or the like. Thus, the amount of received light can be adjusted to prevent a malfunction, and when noise is eliminated, the amount of light emitted is reduced to prevent an unnecessary increase in power consumption.

It is the functional block diagram which showed embodiment of the detection apparatus by this invention. It is a time chart which shows the influence by the light projection waveform of the detection apparatus by a prior art, and noise etc. of a light reception waveform. It is a time chart which shows the influence by the noise etc. of the light projection waveform of the detection apparatus by this invention technique, and a light projection waveform and a light reception waveform.

Hereinafter, an example of an embodiment of a detection device of the present invention will be described with reference to the drawings.
The present invention constitutes a detection device as shown in FIG. The controller 30 transmits a projection signal T to the projector 10. The projector 10 projects the light beam 2 from the light projecting unit 11 in accordance with the projection signal T. When the light receiving unit 21 of the light receiver 20 receives the light beam 2, the light receiver 20 transmits a light reception signal R that is a pulse signal to the controller 30. The controller 30 determines whether or not the light beam 2 between the light projecting unit 11 and the light receiving unit 21 is blocked by the detection object 5 based on the light reception signal R. If it is determined that the light is blocked, the controller 30 outputs the detection output 4 to the automatic door (not shown). Send to the control panel. The controller 30 receives a power input 31 from a power supply device (not shown), and supplies power to the projector 10 and the light receiver 20 (not shown). Noise 6 or the like 6 is mixed with the received light signal R via the projector 10, the light beam 2, the light receiver 20, the controller 30, the power input 31, and their wiring. This detection apparatus is characterized in that the controller 30 corrects the threshold value in consideration of the influence of noise 6 included in the light reception signal R.

  FIG. 2 shows the waveforms of the light projection signal T and the light reception signal R according to the prior art, and compares the influence of noise 6 and the like. The waveform of the light receiving signal R varies depending on the light projecting circuit, the light receiving circuit, the program, and the like, but here it is a pulse waveform with rounded rise and fall due to the influence of the time constant of the CR circuit in the light receiving circuit.

  For explanation of the prior art, FIGS. 2 (a) to 2 (c) show typical examples of light projection and light reception for four times. 2 is blocked between the light projector 10 and the light receiver 20, so that the light beam 2 does not reach the light receiver 20, and the distance between the light projector 10 and the light receiver 20 is The broken line indicates the waveform when the light beam 2 reaches the light receiver 20 without being blocked.

  FIG. 2A shows that the magnitude of the light projection signal in the projector according to the prior art is constant regardless of the presence or absence of the influence of noise 6 or the like.

  FIG. 2B shows a waveform when the received light signal R is not affected by the noise 6 in the prior art detection device in a place where the noise 6 is not present. In the light reception signal R2 (2), the controller 30 determines that the light projector R and the light receiver are disconnected when the light reception signal R and the threshold value 1 are compared.

  FIG. 2C shows a waveform when the received light signal R is affected by noise or the like 6 in the conventional detection device. In the light reception signal R2 (2), the controller 30 compares the light reception signal R with the threshold value 1 and the light reception signal R is affected by noise 6 and the like even though the light projector 10 and the light receiver 20 are disconnected. Since it is determined that it is not blocked by being larger than the threshold value 1, it becomes a cause of malfunction.

  FIG. 3 shows the waveforms of the light projection signal T and the light reception signal R according to the technique of the present invention, and compares the influence of noise 6 and the like. Here, the detection apparatus has the same configuration as in FIG. 1 according to the present invention, and the noise 6 is the same as that in FIG. 2 for comparison with the prior art. The waveform of the light receiving signal R varies depending on the light projecting circuit, light receiving circuit, program, etc. Here, the pulse waveform has a rounded rise and fall due to the influence of the time constant determined by the capacitor capacity and resistance component of the CR circuit in the light receiving circuit. It has become.

  3A to 3D show representative examples of light projection and light reception for four times. Further, the light reception signal R2 (2) in FIG. 3 is blocked between the projector 10 and the light receiver 20, so that the light beam 2 does not reach the light receiver 20. The broken line indicates the waveform when the light beam 2 reaches the light receiver 20 without being blocked.

  FIG. 3A shows the magnitude of the projection signal T in the projector according to the present invention where there is no noise 6 or the like. In a state where there is no noise 6 or the like, the projection signals T (1) to (4) have the same magnitude as the projection signal T of the prior art in FIG. The magnitude of the projection signal T in the presence of noise 6 will be described later.

  FIG. 3 (b) shows the waveform of the received light signal R in the detection device according to the present invention in a place where there is no noise 6 and the like. Shows that it works in the same way. As an example, since the light reception signal R2 (1) is higher than the threshold value 1, it is determined that the projector and the light receiver are not blocked. Further, as shown in the light reception signal R2 (2), when the light projector 10 and the light receiver 20 are blocked, the light reception signal R2 is determined to be blocked unless the threshold value 1 is reached. In addition, the detection device according to the present invention has the threshold value 2, but is equal to the threshold value 1 when there is no noise 6 or the like.

  FIG. 3C shows the magnitude of the light projection signal T of the projector according to the present invention in a place where there is noise 6 or the like. In FIG. 3A, the light projection signal T in the state without noise 6 is shown. However, as shown in the light projection signal T (2) and the light projection signal T (3) in this drawing, the light reception signal R It can be seen that the light projection signal T increases when the signal is affected by noise 6 or the like.

  FIG. 3 (d) shows the waveform of the received light signal R when the detector according to the present invention is affected by noise 6 or the like. Each of the section t (1) to the section t (4) indicates a period from immediately after the fall of the previous light reception signal to immediately before the next light projection starts. The light reception signal R1 is obtained by calculating the light reception signal R when the light projector 10 is not projecting the light beam 2, and represents the magnitude of noise 6 or the like.

  As described above, the waveform of the light receiving signal R is a pulse waveform with rounded rise and fall due to the influence of the time constant determined by the capacitor capacity and resistance component of the CR circuit in the light receiving circuit. Therefore, the light reception signal R1 rises and falls logarithmically by switching the presence or absence of the input of the light projection signal T to the light receiver 20. From this, since the time required for the fall (time required for discharging the capacitor) can be known from the capacitor capacitance value and the resistance value, the light reception signal R is acquired and used as the light reception signal R1 after the time calculated from these values has elapsed. Thus, since the light reception signal R1 is not affected by the light projection signal T, it is possible to obtain a value in which only noise 6 or the like is input. The longest time required for the fall is stored in the controller 30 in advance, and the light reception signal R is not acquired in order to calculate the light reception signal R1 until this time elapses after the light projection of the light projection signal T is completed. .

  The light reception signal R1 is stored for each section t, and the light reception signal R1 (4) is determined from the light reception signal R1 (1). For each light reception signal R1, the light reception signal R is acquired at least once in the interval t, and the average value, median value, or other calculation value is obtained. In this case, the light reception signal R1 that is a noise signal can be calculated with high accuracy by including the middle of the section t and immediately before the start of light projection. The more the number of acquisitions of the light reception signal R, the higher the reliability, but the increase in the amount of data is not possible. By setting the middle of the section t and immediately before the start of light projection, the reliability can be improved even twice.

  In the prior art, the magnitudes of the projection signals T (1) to T (4) are constant as shown in FIG. As shown in FIG. 3C, in the technique of the present invention, the light projection signal T is also increased together with the setting of the threshold value 2. If the light beam is not blocked, the light reception signal R2 is linked with the light projection signal T (1) to the light projection signal T (4), and the light reception signal R2 (1) = the light reception signal R2 (4) <the light reception signal R2. Since (2) <light reception signal R2 (3) increases, it is possible to secure a margin of the light reception signal R2 with respect to the threshold value. If the influence of the noise 6 is eliminated, the threshold 2 is the threshold 2 (1) before the influence of the noise 6 etc. and the light projection signal T is the noise as shown in the light reception signal R2 (4) in FIG. Thus, it returns to the same magnitude as the light projection signal T (1) before being affected by 6 and so on, and current consumption can be suppressed.

  The threshold value 2 is determined according to the threshold value 1 and the received light signal R1 from the storage of the received light signal R1 to the rising edge of the projected light signal T, and these are changed from the threshold value 2 (1) to the threshold value 2 (4). It is used in comparison with the received light signal R2 stored at the time of each next light projection. Therefore, even if it receives the influence of noise 6 etc., it does not become inoperable.

  As described above, the threshold value 2 is determined according to the threshold value 1 and the light reception signal R1. Specifically, the threshold value 1 is obtained by multiplying the light reception signal R1 by a coefficient set in the controller 30 in advance. Use.

  The light receiving signal R2 (2) of the prior art in FIG. 2 (c) is larger than the threshold value 1 and is inoperative due to erroneous judgment that there is no interruption, but the light receiving signal R2 ( Since 2) is smaller than the threshold value 2 (2), it can be normally determined that the projector and the light receiver are blocked.

While typical examples of the present invention have been described above, the present invention is not necessarily limited to the above embodiments. For example, a case where the projector, the light receiver, and the controller are separated and the detection device detects that the light projector and the light receiver are interrupted is described as an example. May be integrated, or it may be a detection device that detects that the light projector and the light receiver are integrated and that the light reflector is cut off.
Moreover, the light projection signal may be a combination of a plurality of periods instead of a single period.
Further, between the projector, the light receiver, and the controller, either a wired connection or a wireless connection may be used. It is also conceivable that the projector, the light receiver, and the controller separately input power.

DESCRIPTION OF SYMBOLS 1 Light projection signal 10 Light projector 11 Light projection part 2 Light beam 20 Light receiver 21 Light receiver part 3 Light reception signal 30 Controller 31 Power supply input 4 Detection output 5 Detection target 6 Noise etc.

Claims (4)

Consists of a controller, projector and receiver,
The projector projects the projection signal received from the controller as a light beam,
The light receiver receives the light beam projected from the projector and transmits it as a light reception signal to the controller,
The controller transmits the light projection signal to the light projector and receives the light reception signal from the light receiver,
A light receiving signal R1 when the light projector is not projecting;
Storing the light receiving signal R2 when the projector is projecting light;
Threshold 1;
A threshold value 1 and a threshold value 2 to which a value corresponding to the light reception signal R1 is added;
A detection device that emits a detection signal when the light reception signal R2 is smaller than a threshold value 2. 2. The light receiving signal according to claim 1, wherein the controller receives a light reception signal after a lapse of time taken to discharge a capacitor of a light receiving circuit in the light receiving device stored in advance after the light projecting end of the light projecting device until light projection starts. A detection device that stores R1. The light receiver according to claim 1 or 2, wherein the light receiver receives light at a midpoint immediately after the light is projected by the light projector and immediately before the light is projected, and a light reception signal immediately before the light is projected by the light projector.
Is a light receiving signal R1. 4. The detection device according to claim 1, wherein the controller corrects the magnitude of the light projection signal in accordance with the magnitude of the light reception signal R1.

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