Proximity detection sensing system

Abstract

The proximity detection sensing system of this disclosure enables stable sensing for proximity detection using a variety of sensor configurations. [Solution] The proximity detection sensing system comprises a transmitter that forms an electromagnetic field with an transmitting electrode and transmits an AC signal, and a receiver that receives the AC signal from the transmitter, wherein the transmitter has an oscillator and an transmitting electrode, and the output terminal of the oscillator is connected to the transmitting electrode, and the receiver has a detector and a first receiving electrode, and the first input terminal of the detector is connected to the first receiving electrode, and the receiver has a circuit GND as a receiver, and the circuit GND is insulated from the first receiving electrode of the receiver and connected to a conductor that forms capacitance with the ground.

Description

Technical Field

[0005] ,

[0001] This disclosure relates to a proximity sensing system.

Background Art

[0002] Conventionally, there has been a technology related to an automated guided vehicle equipped with sensors for preventing deviation (Patent Document 1). This automated guided vehicle of this technology is characterized by including ultrasonic sensors that can detect surrounding obstacles and enable the vehicle to run again on the running line when the vehicle deviates from the running line in the front, rear, left, or right directions.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, ultrasonic sensors have been used as proximity sensing means for an AGV (automated guided vehicle) to detect surrounding obstacles. By arranging ultrasonic sensors on each of the four sides of the AGV, surrounding obstacles can be detected, enabling collision avoidance control.

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[0006] This disclosure is made in view of the above circumstances and aims to provide a proximity detection sensing system that enables stable and diverse sensing for proximity detection using various sensor configurations. [Means for solving the problem]

[0007] To achieve the above objective, the proximity detection sensing system of this disclosure comprises a transmitter that forms an electromagnetic field with an transmitting electrode and transmits an AC signal, and a receiver that receives the AC signal from the transmitter, wherein the transmitter has an oscillator and an transmitting electrode, and the output terminal of the oscillator is connected to the transmitting electrode, and the receiver has a detector and a first receiving electrode, and the first input terminal of the detector is connected to the first receiving electrode, and the receiver has a circuit GND as a receiver, and the circuit GND is insulated from the first receiving electrode of the receiver and connected to a conductor that forms capacitance with the ground. [Effects of the Invention]

[0008] The proximity detection sensing system of this disclosure enables stable and diverse sensing for proximity detection using various sensor configurations. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an explanatory diagram of the conventional method in which capacitance is provided with respect to the ground. [Figure 2] Figure 2 shows an example of applying an ultrasonic sensor to an AGV (Automated Guided Vehicle). [Figure 3] Figure 3 shows an example where the number of sensors was increased to address blind spots. [Figure 4] Figure 4 shows an example of obstacle detection in a conventional automated guided vehicle. [Figure 5] Figure 5 shows the configuration of the proximity detection sensing system of this disclosure. [Figure 6] Figure 6 shows an example of the form of a transmitter. [Figure 7] Figure 7 shows an example of a receiver configuration. [Figure 8A] Figure 8A shows an example where the receiver has two receiving electrodes. [Figure 8B] Figure 8B shows an example where a receiver is placed in the mechanism. [Figure 9] Figure 9 shows a sequence illustrating the flow of detection processing in a proximity sensing system. [Figure 10] Figure 10 shows an example where the receiving unit is transported by an automated guided vehicle (AGV) on a trolley. [Figure 11] Figure 11 shows an example of an arm robot whose receiving body has a movable part. [Figure 12] Figure 12 shows an example of a detector design. [Figure 13] Figure 13 shows an example of one configuration of the receiving electrode. [Figure 14] Figure 14 shows two examples of the receiving electrode. [Figure 15] Figure 15 shows an example of a detector configuration. [Figure 16] Figure 16 shows an example of a detector signal waveform. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. First, the problems of the prior art and an overview of the method of this disclosure will be explained.

[0011] Figure 1 is an explanatory diagram of the conventional method in which capacitance with the ground is provided. The problems of the conventional method are illustrated using an AGV (Automated Guided Vehicle) as an example. By using the body (surface, frame, chassis) as a detection electrode, the AGV itself can detect the proximity of an emitter with little or no directionality. In this case, the input terminal (receiving terminal) of the detector is connected to the detection electrode, and the output of the detector corresponding to the received electromagnetic field is obtained. However, the circuit GND of the detector is not connected to anything (floating). In this configuration, the circuit GND also fluctuates to the same extent as the detection electrode, so the effective input voltage becomes small. As a result, the receiving sensitivity of the detector becomes small.

[0012] Therefore, in the configuration of such a conventional automatic guided vehicle, as described in the above problems, the performance of proximity sensing was not sufficient.

[0013] For such cases, in this method, as a countermeasure, it is aimed to fix the circuit GND to a stable potential. Since the AGV moves on the ground with insulated tires, it cannot utilize an external stable potential. Also, when an electrode facing the ground (GND) is formed, a capacitance is formed between the ground and the electrode. The larger this capacitance becomes, the more equivalent the potential of the electrode is to the ground (GND). By connecting the circuit GND to this electrode, the circuit GND can be made smaller than the swing width of the receiving electrode. As a result, the reception sensitivity can be improved. Also, in this method, the connection to each part of the input terminal and the circuit GND may be interchanged.

[0014] Also, conventionally, since the ultrasonic waves emitted from an ultrasonic sensor exhibit a diverging straightness, the detection area of an obstacle becomes spotty and narrow. FIG. 2 is an application example of an ultrasonic sensor to an AGV. FIG. 3 is an example in which sensors are increased for dead angle countermeasures.

[0015] As shown in Figure 2, when sensors are installed in four locations on an automated guided vehicle (AGV), blind spots for obstacle detection are created, particularly in the corners and above. To compensate for these blind spots, it is conceivable to increase the number of sensors (Figure 3). However, this increases the number of sensors (parts), signal lines, and power consumption, resulting in a more complex system. Furthermore, it requires more installation space. AGVs transport carts loaded with containers and other objects. Figure 4 shows an example of obstacle detection in a conventional AGV. Often, these carts have a larger base area and greater height than the AGV. As in example (a), there is no problem with the detection area when the cart is alone. As in example (b), it is not possible to handle carts or containers that exceed the size of the AGV. Also, as in example (c), it is not possible to handle situations where carts and containers are stacked in the height direction. When transporting carts, obstacle detection needs to be performed considering the size of the AGV and the cart together, but conventional sensors (ultrasonic sensors) cannot handle this. This problem cannot be solved by using other sensors such as near-infrared sensors or cameras instead of ultrasonic sensors. Furthermore, even if the issue could be addressed with one of the sensors, the obstacle detection area would have to be reconfigured every time the size of the transport cart changes, making operation extremely cumbersome. This method aims to solve these problems.

[0016] Figure 5 shows the configuration of the proximity detection sensing system of this disclosure. In the example in Figure 5, the transmitter is a human and the receiver is an AVG (Automated Guided Vehicle).

[0017] The transmitter 102 has an oscillator 102A and an oscillating electrode 102B, with the output terminal of the oscillator 102A connected to the oscillating electrode 102B. The transmitter 102 generates an electromagnetic field with the oscillating electrode 102B and emits an AC signal. The oscillating electrode 102B is sized to generate a frequency that is 1 / 6 or less of the wavelength of the generated AC signal. The oscillator 102A and the oscillating electrode 102B may be integrated.

[0018] The receiver 104 receives AC signals from the transmitter 102. The receiver 104 has a first receiving electrode 104A, a detector 104B, and a controller 104C. The first input terminal of the detector 104B is connected to the first receiving electrode 104A. In addition, the AVG configuration includes a loading platform, a lifting section, a main body, an insulating area, and a lower section. The loading platform, lifting section, and main body are electrically connected first receiving electrodes 104A. Electrically connected here includes a state of capacitive coupling at the frequency of the AC signal used. The lower section corresponds to the circuit GND. Thus, the receiver 104 has a circuit GND as its receiver, and the circuit GND is insulated from the first receiving electrode 104A of the receiver 104 and connected to a conductor that forms capacitance with the ground. Insulation here refers to having a sufficiently high impedance (approximately 10kΩ or more) at the frequency used.

[0019] The detector 104B detects proximity between the transmitter and receiver based on the AC signal received from the receiving electrode 104A.

[0020] 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.

[0021] 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.

[0022] Figure 6 shows an example of the transmitter configuration. The transmitter 102 is not limited to a human, but may also be (A1) an AVG or (A2) a wall. Figure 7 shows an example of the receiver configuration. (B1-1) and (B1-2) are examples in which the receiving electrode and the circuit GND are electrically separated, and the detector 104B is also connected to the circuit GND, showing that the circuit GND is not in contact with the ground / is in contact with the ground. For (B1-2), the circuit GND is connected to a conductor placed directly on the ground. The conductor part moves with the moving body (is dragged along). (B2-1) and (B2-2) are examples in which the receiver is an arm robot. The arm robot has a movable body with movable parts and a conductive surface part. The insulating region and circuit GND are the same as for the AVG.

[0023] Figure 8A shows an example in which the receiver has two receiving electrodes. As shown in (C1), there are no particular restrictions on the shape of the circuit GND. (C1) is an example in which the receiving electrode 2 (second receiving electrode) is installed on the upper part of the detector 104B together with the receiving electrode 1 (first receiving electrode). (C2) is an example in which the receiving electrode 2 is installed on one wheel side and the other side is the circuit GND. (C3) is an example in which the receiving electrode 2 is embedded in an insulating area. In this way, the conductor part insulated from the first receiving electrode, or a part of the conductor part, can be configured to be located in the direction of the ground below the receiving electrode of the receiver 104. In addition, the second input terminal of the detector 104B is connected to the second receiving electrode and to the conductor part insulated from the first receiving electrode and the circuit GND. The second input terminal of the detector 104B may also be connected to the circuit GND.

[0024] Furthermore, the capacitance between the first receiving electrode and the insulated conductor and the ground is greater than the capacitance between the first receiving electrode or the second receiving electrode and the receiver. Also, if the connection between the input terminal and the circuit GND is reversed, the capacitance between the first receiving electrode or the second receiving electrode and the receiver will be greater than the capacitance between the first receiving electrode and the insulated conductor and the ground.

[0025] Furthermore, the receiver of the receiver unit 104 may be configured to be placed on a predetermined mechanism, not limited to a configuration in contact with the ground. The mechanism is, for example, a stand or machine installed on a mounting surface such as the ground or floor, and the receiver is placed at any location on the mechanism. Figure 8B shows an example of a receiver placed on a mechanism. (C4) is an example of a small, portable, stationary receiver. (C5) is an example of a receiver placed on a stand. The electrical characteristics of the stand include insulators and conductors. The placement method may be placement only, semi-fixed with tape, or mechanically fixed (screwed, etc.). Alternatively, the stand, which includes conductors, may be electrically connected at the same time as placement / fixing. (C6) is an example of a receiver mounted on a machine. In this way, a conductor part insulated from the first receiving electrode, or a part of said conductor part, is placed at any location on the mechanism installed on the predetermined mounting surface. In addition, the conductor part insulated from the first receiving electrode and the conductor part provided on the machine installed on the predetermined mounting surface are electrically connected.

[0026] Next, the operation of the proximity detection sensing system 100 according to the embodiment of this disclosure will be described. Figure 9 is a sequence showing the flow of the detection process in the proximity detection sensing system 100.

[0027] 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.

[0028] In step S102, the receiving electrode 104A of the receiver 104 receives the AC signal from the transmitter 102.

[0029] In step S104, the detector 104B of the receiver 104 detects the proximity of the transmitter and receiver based on the AC signal received from the receiving electrode 104A.

[0030] 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.

[0031] (modified version) Next, we will explain variations of the modified form.

[0032] Figure 10 shows an example where the receiver is transported by an automated guided vehicle (AGV). This shows the AGV using this technology transporting the cart. As shown in (D1), the conductive cart is electrically connected to the AGV's platform, so when the AGV and the cart come into contact, the cart also functions as a receiving electrode. As a result, it becomes possible to detect the proximity of the transmitter at the cart. Also, as shown in (D2), even if an insulating region is provided between the AGV and the cart, they are connected by capacitive coupling. From the above, it can be concluded that with this technology, the proximity of the transmitter can be detected whether the AGV is transporting the cart or not. Thus, the first or second receiving electrode of the receiver can be configured to be connected to a conductor that can be electrically disconnected.

[0033] Figure 11 shows an example of an arm robot with a movable receiver. Even with an arm robot having a movable receiver, detection of the transmitter becomes possible for the same reasons as with an automated guided vehicle. In this case, if a conductive component is held, that component can be used as a detection electrode to detect the proximity of the transmitter. Furthermore, only the area around the hand of the arm robot needs to be conductive; the arm joints and main body do not need to be conductive.

[0034] By arranging wall-like transmitters as shown in Figure 6 (A2), it is possible to prevent the automated guided vehicle from colliding with the transmitters, that is, from deviating from its route. Also, by placing transmitters at the charging station, the automated guided vehicle can be guided to the charging area by controlling it to move closer to the transmitters. In this way, the controller 104C can arrange multiple transmitters and instruct the movement route of a moving receiver. The controller 104C can also control the receiver to move closer to the electromagnetic field of the AC signal from the transmitters.

[0035] (supplementary explanation) This section explains supplementary information for each component.

[0036] Figure 12 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 12. 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.

[0037] Figure 13 shows an example of a configuration with one receiving electrode. Figure 14 shows an example of a configuration with two receiving electrodes. Figure 15 shows an example of a detector configuration. Figure 16 shows an example of a detector signal waveform.

[0038] As described above, the proximity detection sensing system according to this embodiment enables stable sensing for proximity detection using a variety of sensor configurations.

[0039] 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]

[0040] 100 Proximity Detection Sensing System 102 Transmitter 102A Oscillator 104 Receiver 104A Receiving electrode 104B detector 104C Controller

Claims

1. A transmitter that generates an electromagnetic field with its transmitting electrodes and emits an AC signal, The system comprises a receiver that receives AC signals from the transmitter, The oscillator has an oscillator and an oscillator electrode, and the output terminal of the oscillator and the oscillator electrode are connected. The receiving unit has a first receiving electrode and a detector, and the first input terminal of the detector is connected to the first receiving electrode. The receiver has a circuit GND as its receiver, and the circuit GND is insulated from the first receiving electrode of the receiver and connected to a conductor that forms capacitance with the ground. Proximity detection sensing system.

2. The proximity detection sensing system according to claim 1, wherein the conductor portion or a part thereof, which is insulated from the first receiving electrode, is located in a direction toward the ground below the receiving electrode of the receiving body.

3. The proximity detection sensing system according to claim 1, wherein the second input terminal of the detector is connected to a second receiving electrode and is connected to the conductor portion which is insulated from the first receiving electrode and the circuit GND.

4. The proximity detection sensing system according to claim 3, wherein the second input terminal of the detector is connected to the circuit GND.

5. The proximity detection sensing system according to claim 1, wherein the capacitance formed between the conductor portion insulated from the first receiving electrode and the ground is greater than the capacitance formed between the first receiving electrode or the second receiving electrode and the receiver.

6. The proximity detection sensing system according to claim 1, wherein the capacitance between the first receiving electrode or the second receiving electrode and the receiver is greater than the capacitance between the conductor portion, which is insulated from the first receiving electrode, and the ground.

7. The proximity detection sensing system according to claim 1, wherein the first receiving electrode or the second receiving electrode of the receiver is connected to an electrically disconnectable conductor.

8. The proximity detection sensing system according to claim 1, wherein a plurality of the transmitters are arranged to indicate the movement route of a moving receiver.

9. The proximity detection sensing system according to claim 1, wherein the receiver is controlled to be in close proximity to the electromagnetic field of the AC signal from the transmitter.

10. The proximity detection sensing system according to claim 1, wherein the GND of the circuit is insulated from the first receiving electrode of the receiving body, and at least a portion of the conductor that forms capacitance with the ground is in contact with the ground.

11. The proximity detection sensing system according to claim 1, wherein the conductor portion or a part thereof, which is insulated from the first receiving electrode, is positioned at any location on a mechanism installed on a predetermined mounting surface.

12. The proximity detection sensing system according to claim 1, wherein the conductor portion insulated from the first receiving electrode and the conductor portion provided in a mechanism installed on a predetermined mounting surface are electrically connected.

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