Communication system and method for controlling the communication system
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- CANON KK
- Filing Date
- 2022-01-13
- Publication Date
- 2026-08-03
Smart Images
Figure 0007898856000001 
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Figure 0007898856000003
Abstract
Description
Technical Field
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[0001] The present invention relates to a communication system and a method for controlling the communication system.
Background Art
[0002] A communication system that performs wireless communication using electromagnetic field coupling between adjacent devices is known. For example, by performing wireless data transmission in a swiveling movable part such as a robot arm part or a network camera, it is possible to reduce cable wear and realize free swiveling. Patent Document 1 discloses a technique in which a rotating coupler and a fixed coupler perform data communication by electromagnetic field coupling.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] < First The signal is output to one end of each of the two long couplers, and the receiving circuit is First The signal output from the short coupler is received, First The short coupler has the above First A signal is input from at least one of the two elong couplers by electromagnetic field coupling, and the signal control means, First Short coupler and the above First Based on the degree of coupling between each of the two long couplers, First The method is characterized by controlling the signal output from the transmitting circuit so as to stop or attenuate the signal to a long coupler whose coupling with the short coupler is weaker than that of other long couplers. [Effects of the Invention]
[0007] According to the present invention, it is possible to reduce the effects of interference noise in a wireless communication system while suppressing an increase in system size. [Brief explanation of the drawing]
[0008] [Figure 1] Block diagram showing an example of the configuration of the communication system according to the first embodiment. [Figure 2] A diagram showing an example of the configuration of the communication system according to the first embodiment. [Figure 3] A diagram showing an example of the configuration of the communication system according to the first embodiment. [Figure 4] A diagram showing an example of the configuration of a communication system according to the second embodiment. [Figure 5] A diagram showing an example of the configuration of a communication system according to the third embodiment. [Modes for carrying out the invention]
[0009] Each embodiment will be described below with reference to the drawings. Note that the following embodiments do not necessarily limit the present invention. Furthermore, not all combinations of features described in each embodiment are essential to the solution of the present invention.
[0010] [First Embodiment] Figure 1 shows an example of the configuration of a communication system 100 according to the first embodiment. The communication system 100 performs wireless communication using electromagnetic field coupling between a long coupler and a short coupler. In this embodiment, electromagnetic field coupling includes both electric field coupling and magnetic field coupling. That is, wireless communication between transmission lines may be performed by electric field coupling, by magnetic field coupling, or by both electric field coupling and magnetic field coupling.
[0011] The communication system 100 comprises a transmitting communication device 101, a receiving communication device 102, and a movement control unit 103. The transmitting communication device 101 has a transmitting circuit 110, long couplers 120, 130, termination circuits 140, 150, and a transmitting signal control unit 160. The receiving communication device 102 has a short coupler 170 and a receiving circuit 180. The transmitting communication device 101 and the receiving communication device 102 may be a first and second part included in a single device, or they may be separate devices.
[0012] The communication system 100 has a structure for supporting the transmitting communication device 101 and the receiving communication device 102 in a predetermined positional relationship (a positional relationship in which the long couplers 120, 130 and the short coupler 170 face each other). For example, if the communication system 100 is a gantry loader, the transmitting communication device 101 is the traveling part, and the receiving communication device 102 is the fixed part. Note that the wireless communication system 100 is not limited to a gantry loader, but may also be a network camera or a robotic arm.
[0013] The long couplers 120 and 130 function as antennas for wireless communication between the transmitting communication device 101 and the receiving communication device 102 by electromagnetically coupling with the short coupler 170. The transmitting circuit 110 generates electrical signals and inputs them to one end (input end) of the long couplers 120 and 130. The transmitting circuit 110 can be configured with a combination of signal sources, differential buffers, amplifiers, distributors, attenuators, switches, etc., and can control the amplification, attenuation, and ON / OFF status of each signal output to the long couplers. However, the method of signal control is not limited to this and may be performed by software or by other hardware configurations.
[0014] Termination circuits 140 and 150 are connected to the other ends (output ends) of the long couplers 120 and 130. When a signal is input from the transmitting circuit 110 to the input ends of the long couplers 120 and 130, the signal is transmitted towards the other ends (output ends) of the long couplers 120 and 130. In other words, the long couplers 120 and 130 function as a transmission line. The receiving circuit 180 restores the voltage generated in the short coupler 170 by electromagnetic field coupling to an electrical signal in response to the input of an electrical signal to the long couplers 120 and 130. A comparator can be used to restore the electrical signal, but it may also be restored by other circuits. In this way, the transmitting circuit 110 and the receiving circuit 180 perform wireless communication between the long couplers 120 and 130 and the short coupler 170 by electromagnetic field coupling.
[0015] The movement control unit 103 changes the positional relationship between the long couplers 120 and 130 and the short coupler 170 by moving at least one of the transmitting communication device 101 and the receiving communication device 102 in a predetermined direction. For example, the movement control unit 103 includes a rail that supports the communication device 101, a motor for moving the communication device 101 along the rail, and a power source for supplying power to the motor. Further, instead of moving the entire communication device 101 or communication device 102, the movement control unit 103 may directly move the long couplers 120 and 130, the short coupler 170, or both. Note that the transmitting communication device 101 and the receiving communication device 102 are not limited to a configuration for performing unidirectional communication as shown in FIG. 1, and the communication device 102 may have a long coupler and the communication device 101 may have a short coupler to perform bidirectional communication.
[0016] Hereinafter, the configuration for transmitting a signal from the communication device 101 to the communication device 102 will be described. However, the configuration for transmitting a signal from the communication device 102 to the communication device 101 is the same. However, the configuration for transmitting a signal from the communication device 101 to the communication device 102 and the configuration for transmitting a signal from the communication device 102 to the communication device 101 do not have to be the same. Also, in FIG. 1, the transmitting communication device 101 has two long couplers, but it may have three or more long couplers.
[0017] Next, a signal control method according to the configuration and positional relationship of the long couplers 120 and 130 and the short coupler 170 will be described using FIG. 2. The transmission circuit 110 is composed of signal sources 111 and 112 and differential buffers 113 and 114, and inputs signals to the ends of the long couplers 120 and 130. However, here the transmission circuit 110 is composed of two signal sources, but the transmission circuit 110 may have other configurations. For example, a configuration in which a single signal source is used, the transmission signal is split using a distributor or the like, and an amplifier, a variable attenuator, and a switch are connected in the subsequent stage may also be used.
[0018] The long coupler 120 is a conductor member installed on one surface of the substrate 121, and a ground 122 is installed on the opposite surface of the substrate 121. The long coupler 130 is a conductor member installed on one surface of the substrate 131, and a ground 132 is installed on the opposite surface of the substrate 131. A transmission circuit 110 is connected to one end (input end) of the long couplers 120 and 130, and termination circuits 141 and 151 are connected to the other end. When a signal is input from the transmission circuit 110 to the input ends of the long couplers 120 and 130, the signal is transmitted in the direction of the other ends of the long couplers 120 and 130 (the direction from 180° to 0° and the direction from 180° to 360° in FIG. 2). That is, the long couplers 120 and 130 function as the signal lines of the transmission line. Here, the transmission line is a differential microstrip line, but the form of the transmission line is not limited to this. For example, it may be a strip line or single - end transmission. The other ends of the long couplers 120 and 130 are terminated by the termination circuits 141 and 151. Here, it is assumed that a resistor substantially equal to the characteristic impedance of the long couplers 120 and 130 is connected to the ground, but for example, termination methods with topologies such as Thevenin termination, T - type, and Π - type terminations may also be used.
[0019] The short coupler 170 is a conductor member installed on one surface of the substrate 171, and a ground 172 of a metal member is installed on the opposite surface of the substrate 171. When a signal flows through the long couplers 120 and 130, charges are generated in the short coupler 170 by electromagnetic field coupling, and the signal is output through the receiving circuit 180 connected to the short coupler 170. That is, the short coupler 170 functions as an electrode constituting a capacitor. The configuration of the short coupler 170 is not limited to this. For example, a receiving circuit 180 may be connected to one end of the short coupler 170, a termination circuit may be connected to the other end, and the short coupler 170 may function as the signal line of the transmission line.
[0020] The short coupler 170 is shorter in length than the long couplers 120 and 130 in the extension direction (from 0° to 360° in Figure 2). Also, from a viewpoint perpendicular to the signal transmission direction of the long couplers 120 and 130, the long couplers 120 and 130 and the short coupler 170 are in a positional relationship where at least a portion overlaps. The movement control unit 103 changes the relative position of the short coupler 170 with respect to the long couplers 120 and 130 in the signal transmission direction of the long couplers 120 and 130. For example, the movement control unit 103 moves the short coupler 170 within a range facing the long couplers 120 and 130 (from 0° to 360° in Figure 2). However, the range of movement is not limited to this; the short coupler 170 may move only within a portion of the range on the long couplers 120 and 130, or it may move to the outside of the long couplers 120 and 130. In this example, the long couplers 120 and 130 are formed on substrates 121 and 131 respectively, but the long couplers 120 and 130 may be formed on a single substrate.
[0021] Here, if the short coupler 170 is positioned at a 270° angle to the long couplers 120 and 130, the short coupler 170 will be strongly coupled to the long coupler 130 and will receive signals from the long coupler 130. The signal from the long coupler 120, which is less strongly coupled, will be received as interference noise. This interference noise includes electromagnetic field noise interfering from space and conducted noise interfering from the circuit and ground. In this case, the transmit signal control unit 160 can improve the signal-to-noise ratio in wireless communication between the long coupler 130 and the short coupler 170 by attenuating or stopping the signal input to the long coupler 120. Methods for attenuating or stopping the signal include controlling the ON / OFF state of a switch provided in the transmit circuit or controlling the attenuation amount of a variable attenuator, and these can be implemented by software or other hardware. Furthermore, the transmission signal control unit 160 may detect the positional relationship between the long coupler and the short coupler and perform control accordingly, or it may perform control based on information about the positional relationship and movement sequence that has been set in the system in advance.
[0022] Similarly, by amplifying the signal input to the long coupler 130, which has a strong coupling with the short coupler 170, the signal-to-noise ratio in wireless communication between the long coupler 130 and the short coupler 170 can be improved. Methods for amplifying the signal include controlling an amplifier, which can be implemented by software or other hardware. The attenuation and amplification of the signal input to the long coupler may be varied according to the strength and position of the coupling with the short coupler 170, or amplification and attenuation of each signal may be performed simultaneously.
[0023] Furthermore, as shown in Figure 3, in a system where the substrates 121 and 131 form a ring shape and signals output from two signal sources are input to a long coupler, the signal-to-noise ratio of wireless communication can be improved by controlling it in the same manner as described above. In this case, the substrates 121 and 131 are made of, for example, flexible substrates. With such a structure, the short coupler can be moved circumferentially relative to the long coupler, so that wireless communication can be performed between the long and short couplers while they rotate.
[0024] As described above, the communication system 100 of this embodiment controls the signal input to the long coupler based on the strength of the coupling between the long coupler and the short coupler, reducing interference noise from the long coupler with weak coupling or amplifying the signal to the long coupler with strong coupling. This improves the signal-to-noise ratio of wireless communication. Furthermore, since there is no need to provide a configuration to shield the wireless communication unit to reduce interference noise from external sources or other communications, an increase in system size can be suppressed.
[0025] [Second Embodiment] Next, the communication system 200 in the second embodiment will be described. The differences between the second embodiment and the first embodiment will be mainly described below. Figure 4 is a diagram showing an example of the configuration of the communication system 200 according to the second embodiment. The communication system 200 differs from the communication system 100 in that it has multiple sets of long couplers and short couplers that perform wireless communication, and each set performs wireless communication, and each short coupler is positioned differently from other short couplers with respect to the signal transmission direction of the long coupler.
[0026] In the communication system 200, the transmitting circuit 210 consists of signal sources 211, 212 and differential buffers 213, 214, and inputs a signal to one end (input terminal) of the long couplers 220, 230. The transmitting circuit 310 consists of signal sources 311, 312 and differential buffers 313, 314, and inputs a signal to one end (input terminal) of the long couplers 320, 330. The transmitting circuit 410 consists of signal sources 411, 412 and differential buffers 413, 414, and inputs a signal to one end (input terminal) of the long couplers 420, 430. The other end (output terminal) of the long couplers 220, 230, 320, 330, 420, 430 is terminated by a termination circuit. The long couplers 220, 320, and 420 are positioned adjacent to each other, as are the long couplers 230, 330, and 430. From a viewpoint perpendicular to the signal transmission direction of the long couplers 220 and 230, the long couplers 220 and 230 and the short coupler 270 overlap in position at least partially. The same relationship exists between the short coupler 370 and the long couplers 320 and 330, and between the short coupler 470 and the long couplers 420 and 430. In addition, a receiving circuit (not shown) is connected to one end of the short couplers 270, 370, and 470.
[0027] Here, each short coupler is positioned differently from other short couplers in the extension direction of the long coupler (from 0° to 360° in Figure 4). For example, in Figure 4, short coupler 270 is at 100°, short coupler 370 is at 220°, and short coupler 470 is at 340°. In this case, the transmit signal control unit 260 attenuates or stops the signals input to long couplers with weak coupling between each long coupler and each short coupler, namely long couplers 230, 320, and 420. This reduces interference noise from adjacent long couplers. For example, suppose that the same signal is input to each long coupler. Short coupler 370 mainly receives interference noise from long couplers 230 and 430, but by stopping the signal to long coupler 230, the noise can be reduced by 6 dB compared to when the signal is not stopped. Similarly, the signal-to-noise ratio (S / N ratio) is also improved in wireless communication between the short coupler 270 and the long coupler 220. Note that while this explanation describes the case where three sets of couplers performing wireless communication are adjacent, the number is not limited to three if there are two or more sets.
[0028] Furthermore, the positional relationship of the short couplers is not limited to the example above; for example, the short couplers may be positioned offset by 90° and 180°. Also, when using three or more short couplers, it is preferable to offset two adjacent short couplers, but there may be short couplers that are not offset. In addition, as in the first embodiment, the substrate may have a ring shape. In other words, the second embodiment can also be applied to a system where the 0° position and the 360° position in Figure 4 overlap.
[0029] As described above, in the communication device system 200 of this embodiment, the short couplers 270, 370, and 470 that communicate wirelessly with the long couplers 220, 230, 320, 330, 420, and 430 are arranged offset from the signal transmission direction of the long couplers. Furthermore, by controlling the signal input to the long couplers based on the coupling strength between the long and short couplers, interference noise from adjacent long couplers can be reduced, and the signal-to-noise ratio of wireless communication can be improved. In addition, since there is no need to provide a configuration to shield the wireless communication section to reduce interference noise from the outside or other communications, an increase in the system size can be suppressed.
[0030] [Third Embodiment] Next, the communication system 300 in the third embodiment will be described. The differences between the third embodiment and the second embodiment will be mainly described below. Figure 5 is a diagram showing an example of the configuration of the communication system 300 according to the third embodiment. In the second embodiment, each short coupler was positioned offset from the signal transmission direction of the long coupler. In the third embodiment, the short couplers are positioned at the same position as the other short couplers with respect to the signal transmission direction of the long coupler, but the position of one end (input end) of each long coupler is positioned differently from the other long couplers with respect to the signal transmission direction of the long coupler.
[0031] In the communication system 300, the transmitting circuit 510 consists of signal sources 511 and 512 and differential buffers 513 and 514, and inputs a signal to one end (input terminal) of the long couplers 520 and 530. The transmitting circuit 610 consists of signal sources 611 and 612 and differential buffers 613 and 614, and inputs a signal to one end (input terminal) of the long couplers 620 and 630. The transmitting circuit 710 consists of signal sources 711 and 712 and differential buffers 713 and 714, and inputs a signal to one end (input terminal) of the long couplers 720 and 730. The other end (output terminal) of the long couplers 520, 530, 620, 630, 720, and 730 is terminated by a termination circuit. The long couplers 520, 620, and 720 are positioned adjacent to each other, as are the long couplers 530, 630, and 730. From a viewpoint perpendicular to the signal transmission direction of the long couplers 520 and 530, the long couplers 520 and 530 and the short coupler 270 overlap in position at least partially. The same relationship exists between the short coupler 670 and the long couplers 620 and 630, and between the short coupler 770 and the long couplers 720 and 730. In addition, a receiving circuit (not shown) is connected to one end of the short couplers 570, 670, and 770.
[0032] Each transmitting circuit is connected to the long coupler at a different position from other transmitting circuits in the direction of extension of the long coupler (from 0° to 360° in Figure 5). For example, in Figure 5, transmitting circuit 510 is connected to the long coupler at the 60° position, transmitting circuit 610 at the 180° position, and transmitting circuit 710 at the 300° position. In this case, the transmitting signal control unit (not shown) attenuates or stops the signals input to long couplers with weak coupling between them, i.e., long couplers 520, 620, and 720. This reduces interference noise from adjacent long couplers, as in the second embodiment, and improves communication quality. In this embodiment, the short couplers were positioned at the same position as other short couplers with respect to the signal transmission direction of the long couplers, but the short couplers may be positioned at a different position from other short couplers with respect to the signal transmission direction. Furthermore, the termination circuits connected to each long coupler may be positioned at different locations relative to the signal transmission direction of the long coupler. [Explanation of symbols]
[0033] 100 Communication Systems 110 Transmitter Circuit 120 Long coupler 130 Long coupler 160 Transmission signal control unit 170 Short coupler 180 Receiving Circuit
Claims
1. A communication system that performs wireless communication using electromagnetic field coupling, A transmitting circuit, two first long couplers extending in a predetermined direction, two second long couplers arranged perpendicular to the predetermined direction, a receiving circuit, a first short coupler, a second short coupler arranged perpendicular to the predetermined direction, and signal control means, It has, The transmitting circuit outputs a signal to one end of each of the two first long couplers. The receiving circuit receives the signal output from the first short coupler. The first short coupler receives a signal via electromagnetic field coupling from at least one of the two long couplers mentioned above. The first short coupler and the second short coupler are each positioned at different locations relative to the predetermined direction. A communication system characterized in that the signal control means controls the signal output from the transmitting circuit to stop or attenuate the signal to the long coupler whose coupling with the first short coupler is weaker than that of the other long couplers, based on the degree of coupling between the short coupler and each of the first two long couplers.
2. The communication system according to claim 1, wherein the signal control means amplifies the signal to the long coupler whose coupling with the first short coupler is stronger than that of the other long couplers, based on the degree of coupling between the first short coupler and each of the two first long couplers.
3. The communication system according to claim 1 or 2, further comprising movement control means for moving the first short coupler or the first two long couplers such that the relative position of the first short coupler with respect to the positions of the first two long couplers changes in the predetermined direction.
4. The communication system according to claim 1 or 2, characterized in that the two first long couplers are input to one end from the transmitting circuit and the other end is connected to a termination circuit.
5. The communication system according to any one of claims 1 to 4, characterized in that the first short coupler faces the one long coupler.
6. The communication system according to any one of claims 1 to 5, characterized in that the transmission circuit is generated by a combination of a distributor, a signal source, an attenuator, an amplifier, and a switch.
7. The communication system according to any one of claims 1 to 6, characterized in that the positions at which the transmitting circuit connects to the first two long couplers and the second two long couplers are different with respect to the predetermined direction.
8. The communication system according to any one of claims 1 to 7, characterized in that the termination circuits connected to the two first long couplers and the two second long couplers are arranged at positions different from each other with respect to the predetermined direction.