Mobile object detection system

Abstract

The mobile object detection system disclosed herein enables the detection of mobile objects through a basic configuration that is scalable while suppressing false detections. [Solution] The moving object detection system comprises a transmitter that forms an electromagnetic field with an transmitting electrode and generates an AC signal, and a receiver that receives the AC signal from the transmitter. The first oscillator that generates the AC signal in the transmitter is connected to the transmitting electrode, and the receiver comprises a receiving electrode and a detector. The input terminal of the detector is connected to the receiving electrode, and the detector detects a moving object passing between or approaching the transmitter and the receiver based on the received AC signal.

Description

Technical Field

[0001] The present disclosure relates to a moving object detection system.

Background Art

[0002] Conventionally, there is a technology for ensuring safety regarding collisions with workers in a work space. For example, Patent Document 1 discloses a technology related to a safety device that can realize ensuring safety against collisions between a moving part of an automatic device and a worker or the like. In the technology of Patent Document 1, a danger state detection means for detecting whether at least one of the moving part and the detection target is located in a danger area is provided. A light curtain is used for this detection means.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a technology that uses a light curtain as in Patent Document 1, the problem is that there is a problem of false detection. Since the safety light curtain adopts an optical method, it is vulnerable to dirt and misalignment. That is, when dirt occurs on the light emitting part or the detection surface, the amount of light received by the light receiving part decreases. Also, even if the optical axis is displaced due to vibration or external force during operation, it leads to a decrease in the amount of light received. Due to these decreases in the amount of light received, it may be erroneously detected that a person or a device has entered the danger area, which causes the operating device to suddenly stop. The same problem occurs when a laser sensor is adopted.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a moving object detection system that enables detection of a moving object with a basic configuration having expandability while suppressing false detection.

Means for Solving the Problems

[0006] To achieve the above objective, the mobile object detection system of the present disclosure comprises a transmitter that forms an electromagnetic field with an transmitting electrode and generates an AC signal, and a receiver that receives the AC signal from the transmitter, wherein a first oscillator that generates the AC signal in the transmitter is connected to the transmitting electrode, and the receiver comprises a receiving electrode and a detector, wherein the input terminal of the detector is connected to the receiving electrode, and the detector detects a mobile object passing between or approaching the transmitter and the receiver based on the received AC signal. [Effects of the Invention]

[0007] The mobile object detection system of this disclosure enables the detection of mobile objects through a basic configuration that is scalable while suppressing false detections. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows the configuration of the mobile object detection system of this disclosure. [Figure 2] Figure 2 shows an example of detector output with and without an oscillator in the moving object. [Figure 3] Figure 3 shows an example of the electromagnetic wave characteristics depending on whether or not a mobile device has an oscillator. [Figure 4] Figure 4 shows an image of a mobile object holding a transmitter in close proximity. [Figure 5] Figure 5 shows an example of a transmission pattern. [Figure 6] Figure 6 shows a sequence illustrating the flow of the detection process in a mobile object detection system. [Figure 7] Figure 7 shows a modified example in which the receiving electrode of the receiver is enlarged. [Figure 8] Figure 8 shows a modified example in which the receiving electrode of the receiver is enlarged. [Figure 9] Figure 9 shows an example of the detector output when extended. [Figure 10]FIG. 10 shows an example in which the receiving electrode (or the oscillating electrode) is arranged along the ground. [Figure 11] FIG. 11 shows an example in which the extension of the receiving electrode is realized by capacitive coupling by utilizing the fact that the electromagnetic field is an alternating current signal. [Figure 12] FIG. 12 shows an example in which a plurality of receivers are combined for one transmitter. [Figure 13] FIG. 13 shows an example of the omnidirectional electrode and the directivity of electromagnetic waves. [Figure 14] FIG. 14 shows an example of the opposed electrode and the directivity of electromagnetic waves. [Figure 15] FIG. 15 shows an example of the detector method. [Figure 16] FIG. 16 shows an example of one mode of the receiving electrode. [Figure 17] FIG. 17 shows an example of two modes of the receiving electrode. [Figure 18] FIG. 18 shows a configuration example of the detector. [Figure 19] FIG. 19 shows an example of the signal waveform of the detector.

MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] The moving body detection system of the present disclosure detects a moving body (such as a human, an AGV, etc.) approaching a restricted access zone formed by a transmitter and a receiver, and realizes processing (such as warning) according to the identified moving body. The processing according to the moving body is realized by determining whether the oscillator is held or not and the pattern of the signal emitted by the oscillator.

[0011] FIG. 1 is a diagram showing the configuration of the moving body detection system of the present disclosure. FIG. 2 is an example of the detector output depending on the presence or absence of the oscillator of the moving body. FIG. 3 is an example of the mode of the electromagnetic wave depending on the presence or absence of the oscillator of the moving body. The details of the configuration of FIG. 1 will be described later. Note that, although the moving body is described by taking a human as an example, it may be other movable objects, AVGs, robots, drones, etc.

[0012] As shown in FIG. 2, this method assumes both cases where the moving object has an oscillator and where it does not. A to C on the time axis represent the case where the moving object approaches by movement (see FIG. 3). When the moving object approaches, if it has an oscillator, the detector output increases, and if it does not have an oscillator, the detector output decreases. As shown in FIG. 3, in the case of (A1) without an oscillator, when the moving object approaches, the electromagnetic wave between the poles is shielded and becomes smaller. In the case of (A2) with an oscillator, when the moving object approaches, the electromagnetic wave of the oscillator of the moving object is added to the electromagnetic wave between the poles, and the total amount of the electromagnetic wave increases.

[0013] According to the moving object detection system of the present disclosure, by simply setting up two poles (a transmitter and a receiver), the restricted access zone of the moving object can be determined. Furthermore, in the mode where the moving object holds / does not hold an oscillator that emits an alternating current signal, the way of giving an alarm can be adjusted as follows.

[0014] (1) When the moving object does not hold an oscillator while passing between the poles, an alarm is issued. When it holds an oscillator, it can pass between the poles without an alarm. (2) By determining the transmission pattern of the oscillator in advance, it is possible to selectively give an alarm or not according to the pattern. (3) The condition for issuing an alarm may be the reverse of the above or the same.

[0015] As described above, the moving object detection system emits an alternating current electromagnetic field from the transmitter and receives the alternating current electromagnetic field at the receiver. Both (the transmitter and the receiver) are installed at an arbitrary interval. As the moving object (not holding an oscillator) approaches between the installed two, the electromagnetic field of the transmitter is blocked by the moving object, so the electromagnetic field received by the receiver attenuates. By detecting this attenuation, it becomes possible to detect the approach and passage of the moving object. Also, when the passing moving object holds an oscillator that generates an alternating current electromagnetic field detectable by the receiver, the electromagnetic field reaching the receiver becomes larger. That is, it is possible to detect the approach and passage of the moving object having an oscillator. Also, by determining the transmission pattern of the held oscillator in advance, control can be selectively used for each pattern.

[0016] The components of the mobile object detection system consist of a transmitter that generates an electromagnetic field and a receiver that receives that electromagnetic field, which can be installed at any distance from each other. The receiver has an electromagnetic field detector and a controller. The controller operates according to the magnitude of the electromagnetic field received by the detector. This operation may include illuminating a warning light, issuing an alarm, or recording or communicating the increase or decrease in the electromagnetic field. A mobile object that approaches or passes between the two may also have an oscillator. The oscillator is assumed to have at least one transmission pattern. The transmitter and receiver may be fixed, portable, or movable.

[0017] As shown in Figure 1, the mobile object detection system 100 of this embodiment consists of a transmitter 102 and a receiver 104, and detects the passage or proximity of a mobile object 106. For the sake of explanation, the illustration shows an example in which the mobile object 106 holds the oscillator 106A (second oscillator), but it may not hold it. Also, for the sake of explanation, the reference numerals for each component (transmitter, receiver, oscillator, etc.) may be omitted in the explanation.

[0018] The oscillator 102 comprises an oscillator 102A (first oscillator) that generates an AC signal and an oscillator electrode 102B. The oscillator 102A is connected to the oscillator electrode 102B at its output terminal. The oscillator 102A generates an AC signal and outputs this AC signal to the oscillator electrode 102B from its output terminal. The oscillator 102 generates an AC signal by forming an electromagnetic field with the oscillator electrode 102B. The oscillator electrode 102B is an oscillator electrode of a size that can form a frequency that is 1 / 6 or less of the wavelength of the frequency of the generated AC signal. Note that the oscillator 102A and the oscillator electrode 102B may be integrated.

[0019] The receiver 104 receives an AC signal. The AC signal is a signal from the transmitter 102 (and the mobile body holding the oscillator). The receiver 104 comprises a receiving electrode 104A that receives the AC signal from the transmitter 102, a detector 104B, and a controller 104C. The receiving electrode 104A and the detector 104B are connected by an input terminal.

[0020] The detector 104B detects a moving object 106 passing between or approaching the transmitter and receiver based on the AC signal received from the receiving electrode 104A.

[0021] The controller 104C performs predetermined control in response to the output of the detector 104B. The predetermined control can be set to perform at least one of the following controls: warning, alarm, recording, and data communication.

[0022] The detector 104B and controller 104C are implemented as a computer including a CPU (Central Processing Unit), ROM (Read Only Memory) storing programs for implementing each processing routine, RAM (Random Access Memory) for temporarily storing data, memory as a storage means, and a network interface. The detector 104B is equipped with a comparator that generates on / off signals for various controls based on a preset threshold value for the detected output. The connection between the detector 104B and controller 104C may be wired, or the controller 104C may be installed externally as a wireless connection.

[0023] Here, we will describe the cases in which the mobile body 106 does not hold the transmitter (second oscillator) and does hold it. We will also describe the case in which it holds the transmitter and there is an oscillator pattern.

[0024] The case where the mobile body 106 is not holding an oscillator will be explained. As the mobile body 106 approaches the transmitter and receiver, the electromagnetic field reaching the receiver 104 from the transmitter 102 is blocked, so the received strength of the electromagnetic field at the receiver decreases. The decrease is greatest between the transmitter and receiver, and decreases as the distance increases. When the decrease in received strength exceeds a set value, the controller 104C performs processing such as activating a warning light, alarm, recording data, and data communication. This allows the mobile body 106 (person) to detect intrusion into a dangerous area or restricted area.

[0025] The case where the mobile body 106 holds an oscillator will be explained. As the mobile body 106 approaches, the electromagnetic field from the oscillator of the mobile body 106 reaches the receiver 104. Therefore, by emitting an electromagnetic field of higher strength than the mobile body 106 can block, the received signal strength at the receiver 104 increases as it approaches. When the increase in received signal strength exceeds a set value, the controller 104C performs processing such as activating a warning light, alarm, recording data, and data communication. This allows the mobile body 106 (person) to detect intrusion into a dangerous area or restricted area. As described above, the detector 104B determines whether the mobile body 106 has a second oscillator that the receiver 104 can detect based on the strength of the signal received by the receiver 104. The controller 104C performs predetermined control according to the determination result of whether the mobile body has a second oscillator.

[0026] The case where the mobile body 106 holds an oscillator having an oscillation pattern will be described. When the oscillator has two or more oscillation patterns, the receiver 104 can classify the oscillator into its respective type based on the oscillation pattern it receives. Figure 4 is an image of the mobile body 106 holding the oscillator in close proximity. Figure 5 is a diagram showing an example of an oscillation pattern. As shown in Figure 5, the pattern for oscillation 1 is "111..." and the pattern for oscillation 2 is "1010...". The controller 104C can control the system so that oscillation pattern A (oscillation 1) does not trigger an alarm, oscillation pattern B (oscillation 2) triggers an alarm, or vice versa.

[0027] As described above, the behavior of the strength of the AC signal received by the receiver 104 from the electromagnetic field differs depending on whether the mobile unit 106 holds the oscillator or not. In other words, it is a modulated signal with a different oscillation pattern. By utilizing this characteristic, control can be performed such as issuing a warning if the mobile unit 106 does not hold the oscillator, and not issuing a warning if it holds it. In addition, the number of mobile units 106 that do not hold an oscillator and the number of mobile units 106 that hold an oscillator can be counted, and control can be performed according to the count. Furthermore, by assigning an oscillation pattern to the oscillator, the control can be differentiated depending on the type of oscillator. As described above, when it is determined that the mobile unit has an oscillator, the controller 104C can be configured to perform predetermined control according to the modulated signal detected by the detector 104B, using the signal generated by the mobile unit's oscillator as the modulated signal.

[0028] Next, the operation of the mobile object detection system 100 according to the embodiment of this disclosure will be described. Figure 6 is a sequence showing the flow of the detection process in the mobile object detection system 100.

[0029] In step S100, the transmitter 102 generates an AC signal using the oscillator 102A, forms an electromagnetic wave with the transmitting electrode 102B, and generates an AC signal.

[0030] In step S102, the receiving electrode 104A of the receiver 104 receives the AC signal from the transmitter 102.

[0031] In step S104, the detector 104B of the receiver 104 detects a moving object 106 passing between or approaching the transmitter and receiver based on the AC signal received from the receiving electrode 104A.

[0032] In step S106, the controller 104C of the receiver 104 performs predetermined control (warning, alarm, recording, and data communication) in response to the output of the detector 104B.

[0033] (modified version) Next, we will explain variations of the modified form.

[0034] Figures 7 and 8 show modified examples in which the receiving electrodes of the receiver are expanded. Figure 9 shows an example of the detector output when expanded. When a conductive material (110) is brought into contact with the receiving electrodes, the conductive material also functions as a receiving electrode. The receiving electrodes are also expanded to include receiving electrodes 104A1 and 104A2. Figure 8 shows a case where the electrodes of the transmitter are also expanded, and the intrusion of a moving object in the expanded area can be detected. In the example in Figure 8, the range can be captured more broadly by the expanded receiving electrodes 102B and 104A due to the expansion of the conductive material.

[0035] Figure 10 shows an example where the receiving electrode (or oscillating electrode) is positioned along the ground. The transmitting electrode 102B is composed of transmitting electrode 102B1 and transmitting electrode 102B2. It is composed of receiving electrode 104A1 and receiving electrode 104A2 positioned along a line. Figure 11 shows an example where the receiving electrode is expanded by capacitive coupling, taking advantage of the fact that the electromagnetic field is an AC signal. As described above, the transmitting electrode and the receiving electrode can be expanded in size by contact with an additional conductor or by capacitive coupling.

[0036] Figure 12 shows an example of combining multiple receivers with a single transmitter. The human mobile unit is shown without an oscillator, while the AVG mobile unit is shown with an oscillator. It is also possible to combine multiple transmitters with a single receiver. Furthermore, the frequency of the AC signal from each transmitter may be varied when combining them.

[0037] Furthermore, the directivity may be changed by the electrode shape. Figure 13 shows an example of a full-circumference electrode and the directivity of electromagnetic waves. In the example in Figure 13, the emitted electromagnetic field has no directivity and becomes an isotropic AC signal. Figure 14 shows an example of a counter electrode and the directivity of electromagnetic waves. The emitted electromagnetic field has directivity, and the sensitivity differs depending on the arrangement of the receiver. A is high sensitivity, B is medium sensitivity, and C is low sensitivity. Furthermore, the receiving electrode can be configured in the same way as the transmitting electrode. In this way, for at least one of the two electrodes (transmitting electrode and receiving electrode), all or part of the surrounding portion forming the electrode can be formed and arranged in a linear or arc shape corresponding to the directivity. Here, the electrode formation may be distorted, the linear shape does not have to be straight, and the arc shape does not have to be a perfect circle.

[0038] (supplementary explanation) This section explains supplementary information for each component.

[0039] Figure 15 shows an example of a detector configuration. Detector 104B can have either (a) one receiving electrode or (b) two receiving electrodes, as shown in Figure 15. In the case of one electrode, it uses an amplitude method to detect the received amplitude, while in the case of two electrodes, it detects the difference between signals from the two receiving electrodes, resulting in either an amplitude difference method or a phase difference method. The case with one detection electrode is as shown in Figure 1. In the case of two receiving electrodes for detection in receiver 104, it is as shown in Figure 7. As described above, a receiver can have two receiving electrodes, and the detector can be configured to amplify the difference in magnitude of signals received by the two receiving electrodes or to detect the phase difference.

[0040] Figure 16 shows an example of a configuration with one receiving electrode. Figure 17 shows an example of a configuration with two receiving electrodes. Figure 18 shows an example of a detector configuration. Figure 19 shows an example of a detector signal waveform.

[0041] As described above, the mobile object detection system according to this embodiment enables the detection of mobile objects with a basic configuration that is expandable while suppressing false detections.

[0042] This disclosure is not limited to the embodiments described above, and various modifications and applications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0043] 100 Mobile Object Detection Systems 102 Transmitter 102A Oscillator (First Oscillator) 104 Receiver 104A Receiving electrode 104B detector 104C Controller 106 Mobile Unit 106A Oscillator (Second Oscillator)

Claims

1. A transmitter that generates an AC signal by forming an electromagnetic field with an emitting electrode, The system comprises a receiver that receives the AC signal from the transmitter, The first oscillator that generates the AC signal in the oscillator is connected to the oscillator electrode, The receiving device is equipped with a receiving electrode and a detector, and the input terminal of the detector is connected to the receiving electrode. The detector detects a moving object passing between or approaching the transmitter and the receiver based on the received AC signal. Mobile object detection system.

2. The receiver further comprises a controller connected to the receiver, The mobile object detection system according to claim 1, wherein the controller performs at least one of the following controls in response to the output of the detector: warning, alarm, recording, and data communication.

3. The receiver further comprises a controller connected to the receiver, The detector determines whether the mobile body has a second oscillator that the receiver can detect, based on the strength of the signal received by the receiver. The mobile body detection system according to claim 1, wherein the controller performs predetermined control according to the determination result of whether or not the second oscillator of the mobile body is present.

4. If the determination result is that the aforementioned moving object has an oscillator, The signal generated by the oscillator of the aforementioned mobile unit is used as a modulated signal. The mobile object detection system according to claim 3, wherein the controller performs predetermined control in accordance with the modulated signal detected by the detector.

5. The mobile object detection system according to claim 1, wherein the transmitting electrode of the transmitting body or the receiving electrode of the receiving body can be expanded in size by contact with or capacitive coupling with an additional conductor.

6. The receiving body has two receiving electrodes, The mobile object detection system according to claim 1, wherein the detector detects the amplification or phase difference of the difference in magnitude of the signals received by the two receiving electrodes.

7. The mobile object detection system according to claim 1, wherein, of the transmitting electrode and the receiving electrode, at least one electrode is arranged such that all or part of the surrounding portion forming the electrode is formed in a linear or arc shape corresponding to the directionality.

Images