Control device and control system

Abstract

To suppress beat effects caused by a plurality of oscillation signals when detecting proximity of a signal source outputting an oscillation signal.SOLUTION: A control system includes: at lest one signal source which outputs an oscillation signal; and at least one control device which performs prescribed control for a control object when detecting proximity of the signal source. At least one of signal sources changes over time an oscillation frequency of the oscillation signal outputted from the signal source so that a frequency difference between itself and other signal sources changes over time.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The disclosed technology relates to a control device and a control system.

Background Art

[0002] As technologies related to human protection of robots, the following technologies are known. For example, Patent Document 1 describes a human protection device for a robot that causes the robot to perform an operation to avoid contact with an operator when the robot and an operator working around the robot approach each other. This human protection device includes a wearable device that is worn on the upper body of the operator and applies an alternating current electric field that fluctuates in positive and negative with an absolute value larger than the electrostatic field of the human body near the body surface of the operator, a detection electrode provided on the robot, and a measuring instrument that measures the voltage at the detection electrode. The wearable device applies an alternating voltage to the operator with an alternating voltage adding device and an electrode connected to the alternating voltage adding device. A signal is sent to the controller of the robot based on the voltage value measured by the measuring instrument, and the operation of the robot is controlled.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Industrial robots having movable parts such as manipulators are provided with safety devices to avoid contact between the movable parts and operators. For example, in the human protection device described in Japanese Unexamined Patent Application Publication No. 2021-109288, when the voltage of the electrode on the robot side increases due to the approach of the robot and the operator while an alternating current electric field is applied near the body surface of the operator, a control signal for human protection corresponding to the voltage value measured by the measuring instrument is sent to the controller. The controller decelerates or stops the robot based on the control signal.

[0005] However, according to the above-described apparatus, beats generated by the alternating current electric fields applied to each of a plurality of workers become a problem. The oscillator that generates the alternating current electric field includes a crystal oscillator, a ceramic oscillator, or a silicon oscillator, and outputs an oscillation signal with a stable oscillation frequency. When the oscillation frequency is, for example, 30 MHz, its tolerance is on the order of several Hz or several tens of Hz. On the receiving side of the alternating current electric field, for example, a signal obtained by synthesizing oscillation signals from two oscillators each worn by two workers is received. However, when the frequency difference between the two oscillation signals is on the order of several Hz, beats on the order of several Hz corresponding to the frequency difference are generated. If the frequency of the beats is included in the frequency band when detecting the proximity of the workers, the beats become noise, and it becomes difficult to appropriately detect the proximity of the workers.

[0006] The disclosed technology has been made in view of the above points, and an object thereof is to suppress the influence of beats generated by a plurality of oscillation signals when detecting the proximity of a signal source that outputs an oscillation signal.

Means for Solving the Problems

[0007] A control system according to the disclosed technology includes at least one signal source that outputs an oscillation signal, and at least one control device that performs predetermined control on a control target when detecting the proximity of the signal source. At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source over time so that the frequency difference from other signal sources changes over time.

[0008] At least one of the signal sources may change the oscillation frequency of the oscillation signal output from the signal source regularly or randomly. At least one of the signal sources may change the oscillation frequency of the oscillation signal output from the signal source by frequency hopping or frequency sweeping.

[0009] The control device may include a detector that processes the input oscillation signal and outputs a detection signal corresponding to the distance from the signal source, and a controller that performs predetermined control on a control target when the detection signal indicates the proximity of the signal source.

[0010] The detector may include an extractor that extracts the envelope of the oscillation signal and a low-pass filter that removes high-frequency components included in the extracted envelope. At least one of the signal sources preferably changes the oscillation frequency of the oscillation signal output from the signal source over time such that the ratio of the period during which the frequency difference from another signal source is higher than the cut-off frequency of the low-pass filter is a certain value or more. At least one of the signal sources preferably changes the oscillation frequency of the oscillation signal output from the signal source at intervals of one-third or less of the reciprocal of the cut-off frequency of the low-pass filter. The detector may output, as the detection signal, a signal corresponding to the phase difference between the oscillation signal received by the first electrode and the oscillation signal received by a second electrode different from the first electrode.

[0011] When the detection signal indicates the proximity of the signal source, the controller may decelerate or stop the movement of the movable part of the robot that is the control target, or may change the moving direction of the movable part. When the detection signal indicates the proximity of the signal source, the controller may perform control to issue an alarm. When the detection signal indicates the proximity of the signal source, the controller may perform control to cause the transmitter that is the control target to transmit an alarm signal to a receiver that is integrated with or separate from the signal source.

[0012] A plurality of the signal sources may be provided on a plurality of moving bodies. A plurality of the signal sources may be provided on one moving body.

Advantages of the Invention

[0013] According to the disclosed technology, it is possible to suppress the influence of beats generated by a plurality of oscillation signals when detecting the proximity of a signal source that outputs an oscillation signal.

Brief Description of the Drawings

[0014]

Figure 1

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Figure 12B

Mode for Carrying Out the Invention

[0015] Hereinafter, an example of an embodiment of the disclosed technology will be described with reference to the drawings. In each drawing, the same or equivalent components and parts are given the same reference numerals, and duplicate descriptions are omitted.

[0016] [First Embodiment] FIG. 1 is a diagram showing an example of the configuration of a control system 1 according to an embodiment of the disclosed technology. The control system 1 includes a robot 10, a plurality of signal sources 20A and 20B, and a control device 30. The robot 10 has a conductive housing 11 and a movable part 12 such as a manipulator. The housing 11 constitutes the entire surface portion of the robot 10 including the movable part 12. The control device 30 is provided inside or outside the housing 11 of the robot 10 and controls the robot 10.

[0017] Signal sources 20A and 20B are oscillators that output oscillation signals such as sine waves, triangular waves, and rectangular waves. The frequency of the oscillation signal is not particularly limited, but is, for example, 10 KHz or higher and 300 MHz or lower. Signal sources 20A and 20B are provided on a moving body that works together with robot 10. Signal sources 20A and 20B are, for example, wearable and are worn by worker 21 who works together with robot 10. Signal sources 20A and 20B may be provided on an AGV (Automatic Guided Vehicle) (not shown) that transports materials handled by robot 10. FIG. 1 illustrates two signal sources 20A and 20B respectively worn by two workers 21, but control system 1 may be configured to include three or more signal sources.

[0018] When control device 30 detects that worker 21 wearing signal source 20A or 20B has approached robot 10, control device 30 performs control to avoid movable part 12 from contacting worker 21. FIG. 2 is a diagram showing an example of the configuration of control device 30. Control device 30 includes detector 31 and controller 32. The oscillation signals output from signal sources 20A and 20B propagate through space and are received by detector 31. Detector 31 processes the input oscillation signal and outputs detection signal S D according to the distance from signal sources 20A and / or 20B.

[0019] Detector 31 includes electrode 33, amplifier 34, extractor 35, and low-pass filter (LPF) 36. Electrode 33 functions as an antenna that captures the oscillation signals output from signal sources 20A and 20B. Amplifier 34 amplifies the input oscillation signal. Extractor 35 detects the peak of the oscillation signal amplified by amplifier 34 and extracts the envelope connecting the detected peaks. Low-pass filter 36 removes the high-frequency components included in the envelope extracted by extractor 35. The output signal of low-pass filter 36 is detection signal S D according to the distance from signal sources 20A and 20B. That is, the closer the distance between worker 21 wearing signal sources 20A and 20B and robot 10, the higher the level of detection signal S D becomes.

[0020] When the detection signal S D indicates the proximity of the signal sources 20A and 20B, the controller 32 performs predetermined control on the controlled object. The controller 32 may determine the proximity of the signal sources 20A and 20B, for example, by comparing the detection signal S D with a threshold value. The controlled object may be, for example, the movable part 12 of the robot 10. In this case, when the detection signal S D indicates the proximity of the signal sources 20A and 20B, the controller 32 may decelerate or stop the movement of the movable part 12, or may change the moving direction of the movable part 12. Further, when the detection signal S D indicates the proximity of the signal sources 20A and 20B, the controller 32 decelerates the movement of the movable part 12, and when the detection signal S D indicates a further proximity of the signal sources 20A and 20B, the controller 32 may stop the movement of the movable part 12. Further, the controlled object is not limited to the robot, and may be, for example, an alarm device having no movable part. In this case, when the detection signal S D indicates the proximity of the signal sources 20A and 20B, the controller 32 may control the alarm device so that an alarm is issued from the alarm device. The control device 30 may be provided inside or outside the alarm device. The issuance of the alarm may be, for example, outputting a predetermined voice from a speaker, or lighting a lamp. Further, the controlled object may be a transmitter. In this case, when the detection signal S D indicates the proximity of the signal sources 20A and 20B, the controller 32 may perform control to transmit an alarm signal toward the receiver. The receiver is worn, for example, by the worker 21 wearing the signal source 20A or 20B. The receiver may be integrated with or separate from the signal sources 20A and 20B. When the receiver receives the alarm signal transmitted from the transmitter, it notifies the worker 21 of the proximity by sound, light, etc. The communication between the transmitter and the receiver may be wireless communication.

[0021] Here, consider the case where an oscillation signal output from one signal source is input to the detector 31. FIGS. 3A, 3B, and 3C are diagrams showing waveforms of respective parts of the detector 31 when the oscillation signal input to the detector 31 is output from one signal source. FIG. 3A shows an example of the oscillation signal S O received by the electrode 33. FIG. 3A illustrates the case where a sine-wave oscillation signal S O is received. FIG. 3B is a diagram showing an example of the output signal of the amplifier 34. As shown in FIG. 3B, the amplitude of the oscillation signal S O is amplified by the amplification action of the amplifier 34. The envelope E O of the amplified oscillation signal S n is extracted by the extractor 35. The high-frequency components included in the envelope E n are removed by the low-pass filter 36 and output as the detection signal S D . FIG. 3C is a diagram showing an example of the detection signal S D . The level of the detection signal S D varies according to the distance from the signal source. When the signal source approaches, the amplitude of the oscillation signal S O received by the electrode 33 increases, and the level of the detection signal S D becomes high. On the other hand, when the signal source moves away, the amplitude of the oscillation signal S O received by the electrode 33 decreases, and the level of the detection signal S D becomes low.

[0022] Next, consider the case where oscillation signals output from each of two signal sources are input to the detector 31. In this case, as shown in FIGS. 4A and 4B, a composite signal S O1 formed by combining the oscillation signals S O2 and S C output from each of the two signal sources is received by the detector 31. When the two oscillation signals S O1 and S O2 have a frequency difference of about several Hz, a beat S B of about several Hz corresponding to the frequency difference is generated. Note that the frequencies of the oscillation signals S O1 and S O2 are f O1 and fO2 When this is the case, the beat S B The frequency f b Is represented by the following formula (1). f b =|f O1 -f O2 | ···(1)

[0023] Figure 5 is a diagram showing an example of the relationship between the frequency spectrum of the beat S B And the frequency characteristics of the low-pass filter 36. When the frequency f B Of the beat S b Is lower than the cut-off frequency fc of the low-pass filter 36 (that is, f b <f c In the case), the beat S B Is not removed, and as shown in FIG. 4C, the detection signal S output from the detector 31 D Is affected by the beat S B . The detection signal S shown in FIG. 4C D Appears to show a situation where two stationary signal sources are approaching or moving away from the detector 31. Thus, when the oscillation signals output from each of a plurality of signal sources are input to the detector 31, depending on the difference in the oscillation frequencies of the plurality of oscillation signals, it may be difficult to appropriately detect the proximity of the signal sources.

[0024] To solve this problem, by making the difference in the oscillation frequencies of the two signal sources sufficiently large, the frequency f B Of the beat S b Is made sufficiently higher than the cut-off frequency f c Of the low-pass filter 36 (that is, f b >>f c Is considered). However, in this case, when the number of signal sources increases, frequency management becomes complicated. Also, when adding a signal source, it is necessary to assign an oscillation frequency to the added signal source in consideration of the oscillation frequencies of the existing signal sources.

[0025] In the control system 1 according to the present embodiment, at least one of the signal sources 20A and 20B is configured such that the oscillation frequency of the oscillation signal changes with time. As a result, it is possible to suppress the influence on the beat S B without performing complicated frequency management. The details will be described below. D

[0026] FIG. 6 is a diagram showing an example of the frequency spectrum of each of the oscillation signal S O1 output from the signal source 20A and the oscillation signal S O2 output from the signal source 20B. As shown in FIG. 6, the oscillation frequency of the oscillation signal S O2 is fixed at f2. On the other hand, the oscillation frequency f O1 of the oscillation signal S O1 changes with time within the range of ±f s centered on f1. That is, the oscillation frequency f O1 of the oscillation signal S O1 and the oscillation frequency f O2 of the oscillation signal S O2 are represented by the following formula (2). f1 - f s ≦ f O1 ≦ f1 + f s , f O2 = f2 ··· (2)

[0027] f1 may be equal to f2, or f1 may not be equal to f2. The change with time of the oscillation frequency f O1 of the oscillation signal S O1 may be regular or random. The regular change of the oscillation frequency f O1 may be linear or non-linear. The random change of the oscillation frequency f O1 may be pseudo-random. Also, the change with time of the oscillation frequency f O1 may be due to frequency hopping or frequency sweeping. The change with time of the oscillation frequency f O1 ​It is possible to apply a frequency spectrum spreading technique known as a technique for changing over time. A signal source that outputs an oscillation signal whose oscillation frequency changes over time may be configured to include, for example, a voltage controlled oscillator (VCO) whose oscillation frequency is controlled by an input control voltage, and a voltage generator that generates a control voltage whose voltage level changes over time.

[0028] FIG. 7 is a diagram showing an example of the transition of the oscillation signals S O1 , S O2 and the beat S B generated thereby with respect to the frequency f b . As shown in FIG. 7, by fixing the oscillation frequency f O2 of the oscillation signal S O2 to f2 and changing the oscillation frequency f O1 of the oscillation signal S O1 over time, the frequency difference between the two changes over time. As a result, the frequency f B of the beat S b (= |f O1 (t) - f2|) changes over time.

[0029] The signal source 20A preferably changes the oscillation frequency f B of the oscillation signal S b over time such that the ratio of the period during which the frequency difference from the signal source 20B (i.e., the frequency f c of the beat S O1 ) is higher than the cut-off frequency f O1 of the low-pass filter 36 is equal to or greater than a certain value. Also, the signal source 20A preferably changes the oscillation frequency f O1 of the oscillation signal S O1 at extremely short intervals. Specifically, it is preferable to change the oscillation frequency f c of the oscillation signal S O1 at an interval of 1 / 3 or less of the reciprocal of the cut-off frequency f O1 of the low-pass filter 36. In other words, the number of times of switching per second of the oscillation frequency f O1 is preferably 3 times or more the cut-off frequency f c of the low-pass filter 36.

[0030] FIG. 8 is a diagram showing an example of the relationship between the frequency spectrum of a beat S O1 generated by an oscillation signal S whose oscillation frequency changes over time O2 and an oscillation signal S whose oscillation frequency is fixed B and the frequency characteristics of the low-pass filter 36. When the center frequency f1 of the oscillation signal S O1 changing over time is equal to the fixed oscillation frequency f2 of the oscillation signal S O2 , the frequency f O1 of the beat S O2 generated by the oscillation signals S B and S b changes over time in the range from 0 [Hz] to f s [Hz]. f s corresponds to the change width of the oscillation frequency of the oscillation signal S O1 .

[0031] As a result, the frequency spectrum of the beat S B becomes wider and the peak becomes lower compared to the case where the oscillation frequencies of both the oscillation signal S O1 and the oscillation signal S O2 are fixed (see FIG. 5). As a result, the sum of the signal intensities of the components of the beat S O1 passing through the low-pass filter 36 can be made smaller compared to the case where the oscillation frequencies of both the oscillation signal S O2 and the oscillation signal S B are fixed. As a result, most of the beat S B can be removed by the low-pass filter 36, and the influence of the beat S B on the detection signal S D can be suppressed. As a result, even when oscillation signals output from each of a plurality of signal sources are input to the detector 31, it is possible to appropriately detect the proximity of the signal sources. The above effects are obtained by changing the oscillation frequency of at least one signal source over time, so complicated frequency management is not required. Thus, according to the control system 1 according to the embodiment of the disclosed technology, it is possible to suppress the influence of beats generated by a plurality of oscillation signals without complicated frequency management.

[0032] In the above description, the oscillation frequency f O1 is changed over time, and the oscillation frequency f O2 However, the disclosed technology is not limited to this. O1 and the oscillation frequency f of the signal source 20B O2 In this case, both the oscillation frequency f O1 and f O2 The frequency difference between the oscillation frequency f O1 and f O2 or adjust the oscillation frequency f O1 and f O2 It is preferable that the change over time of at least one of the signal sources is random. In addition, when the control system 1 is configured to include three or more signal sources, it is preferable that all of the signal sources or all of the signal sources except one signal source are configured to change their oscillation frequencies over time.

[0033] In the above description, a case where one signal source is attached to one worker has been exemplified, but it is also possible to provide multiple signal sources on one moving body. FIG. 9 illustrates a configuration in which three signal sources 20A, 20B, and 20C are provided on one moving body 22. The moving body 22 may be a worker who works together with the robot 10 or an AGV. At least two of the signal sources 20A, 20B, and 20C are configured so that the oscillation frequency of the oscillation signal changes over time. As a result, beats generated by the oscillation signals output from the signal sources 20A, 20B, and 20C are added to the detection signal S. D In addition, the center frequencies of the signal sources 20A, 20B, and 20C may be different from one another. Even if it is difficult to detect the proximity of a signal source with a single frequency, by using multiple frequencies with separate bands, a wider frequency band can be covered, making it easier to detect the proximity of a signal source.

[0034] In the above description, a control system including a plurality of signal sources has been exemplified. However, the control system may include only one signal source. In this case, by changing the oscillation frequency of the oscillation signal output from the single signal source over time, it is possible to suppress the influence of beats generated due to other signal sources not belonging to the control system.

[0035] In the above description, a system including one control device 30 has been exemplified. However, the control system may include two or more control devices. Each of the plurality of control devices performs predetermined control on the control target when detecting the proximity of the signal source.

[0036] [Second Embodiment] FIG. 10 is a circuit block diagram showing an example of the configuration of a control device 30A according to a second embodiment of the disclosed technology. The configuration of the detector 31A in the second embodiment is different from that of the detector 31 (see FIG. 2) according to the first embodiment. The detector 31 according to the first embodiment detected the proximity of the signal source by an amplitude detection method. In contrast, the detector 31A according to the second embodiment detects the proximity of the signal source by a phase detection method.

[0037] The detector 31A includes a first electrode 46, a second electrode 47, a first amplifier 41, a second amplifier 42, a phase shifter 43, a multiplier 44, and a signal processor 45. The first electrode 46 and the second electrode 47 each function as an antenna for capturing the oscillation signals output from the signal sources 20A and 20B, respectively. The oscillation signals output from the signal sources 20A and 20B are received by the first electrode 46 and the second electrode 47, respectively. The input terminal of the first amplifier 41 is connected to the first electrode 46. The first amplifier 41 amplifies the oscillation signal received by the first electrode 46 and outputs it as an amplified oscillation signal S 1a as output.

[0038] The input terminal of the second amplifier 42 is connected to the second electrode 47. The oscillation signal received by the second electrode 47 is a signal that is input to the detector 31A via a path different from the path of the oscillation signal received by the first electrode 46. The oscillation signal received by the second electrode 47 is input to the second amplifier 42 as a reference signal. The second amplifier 42 amplifies the reference signal and outputs this as an amplified reference signal S 2a . The amplified oscillation signal S 1a and the amplified reference signal S 2a are converted into rectangular waves by a waveform conversion circuit (not shown). Note that the oscillation signal may be input to the second amplifier 42 and the reference signal may be input to the first amplifier 41.

[0039] The phase shifter 43 changes the phase of the amplified reference signal S 2a by, for example, 90° or -90° and outputs this as a phase-shifted signal S 2b . Note that the amount of phase change imparted in the phase shifter 43 is not limited to 90° or -90° and can be arbitrarily determined. Also, the detector 31A may have two or more phase shifters. Further, the positions of the phase shifter 43 and the second amplifier 42 may be interchanged. The multiplier 44 multiplies the amplified oscillation signal S 1a and the phase-shifted signal S 2b and outputs the multiplication result as a detected signal S3.

[0040] The signal processor 45 performs a process of averaging the detected signal S3 and outputs the averaged signal as a detection signal S D . The level of the detection signal S D becomes higher as the duty ratio of the detected signal S3 becomes larger. The duty ratio of the detected signal S3 changes according to the phase difference between the amplified oscillation signal S 1a and the phase-shifted signal S 2b . The phase difference between the amplified oscillation signal S 1a and the phase-shifted signal S 2b changes according to the distance between at least one of the signal sources 20A and 20B and the robot 10. That is, the level of the detection signal S D changes according to the distance between at least one of the signal sources 20A and 20B and the robot 10. Therefore, the detection signal SD By monitoring, it is possible to detect that at least one of the moving body provided with the signal source 20A and the moving body provided with the signal source 20B is close to the robot 10.

[0041] FIGS. 11A and 11B are time charts showing an example of the signal waveforms of each part of the detector 31A. FIGS. 11A and 11B show the amplified oscillation signal S 1a , the phase shift signal S 2b , the detection signal S3 and the detection signal S D . FIG. 11A shows the case where neither the signal source 20A nor the signal source 20B is close to the robot 10, and FIG. 11B shows the case where at least one of the signal source 20A and the signal source 20B is close to the robot 10.

[0042] When both the signal sources 20A and 20B are at positions sufficiently far from the robot 10, as shown in FIG. 11A, the phase difference between the amplified oscillation signal S 1a and the phase shift signal S 2b is maintained at 90°, which is the amount of phase change given by the phase shifter 43. As a result, the duty ratio of the detection signal S3 becomes 50%, and the level of the detection signal S D obtained by averaging the detection signal S3 becomes zero. When the level of the detection signal S D is near zero, the controller 32 does not perform control to avoid the movable part 12 from contacting the moving body.

[0043] When at least one of the signal sources 20A and 20B approaches the robot 10, the phase of the amplified oscillation signal S 1a changes. In the example shown in FIG. 11B, the phase of the amplified oscillation signal S 1a is advanced compared to the case shown in FIG. 11A. As a result, the phase difference between the amplified oscillation signal S 1a and the phase shift signal S 2b becomes smaller than 90°, which is the amount of phase change given by the phase shifter 43. As a result, the duty ratio of the detection signal S3 becomes larger than 50%, and the level of the detection signal S D obtained by averaging the detection signal S3 becomes larger than zero. The controller 32 uses the detection signal S DWhen the level of is equal to or higher than the threshold value, in order to avoid the movable part 12 from contacting the moving body, predetermined control is performed on the controlled object.

[0044] In addition, as the signal source approaches the robot 10, when the phase of the amplified oscillation signal S 1a changes in the direction of delay, according to the proximity between the signal source and the robot 10, the level of the detection signal S D becomes smaller than zero. In this case, when the level of the detection signal S D is less than the threshold value, in order to avoid the movable part 12 from contacting the moving body, predetermined control is performed on the controlled object.

[0045] Similar to the first embodiment, at least one of the signal sources 20A and 20B is configured such that the frequency of the oscillation signal output from the signal source changes with time. Thereby, even when the detector 31A using the phase detection method is used, the beat S B generated by the oscillation signals output from each of the signal sources 20A and 20B can suppress the influence on the detection signal S D .

[0046] FIGS. 12A and 12B are diagrams showing an example of the waveform of the detection signal S D output from the detector 31A. The period T1 is a period in which no oscillation signal is input, the period T2 is a period in which only the oscillation signal output from one signal source is input, and the period T3 is a period in which the oscillation signals output from each of the two signal sources are input. FIG. 12A shows the case where the oscillation frequencies of the two signal sources input in the period T3 are fixed, and FIG. 12B shows the case where the oscillation frequency of one of the two signal sources input in the period T3 changes with time. As shown in FIG. 12A, when the oscillation frequencies of the two signal sources are fixed, noise is generated in the detection signal S D due to the influence of the beat. On the other hand, as shown in FIG. 12B, when the oscillation frequency of one of the two signal sources changes with time, the influence of the beat is suppressed and no noise is generated in the detection signal S D .

[0047] Regarding the above first and second embodiments, the following additional notes are disclosed. (Additional Note 1) At least one signal source that outputs an oscillation signal, At least one control device that performs predetermined control on a control target when proximity of the signal source is detected, including At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source over time so that the frequency difference from other signal sources changes over time Control system.

[0048] (Additional Note 2) At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source regularly or randomly The control system according to Additional Note 1.

[0049] (Additional Note 3) At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source by frequency hopping or frequency sweeping The control system according to Additional Note 1 or Additional Note 2.

[0050] (Additional Note 4) The control device is A detector that processes the input oscillation signal and outputs a detection signal corresponding to the distance from the signal source, A controller that performs predetermined control on a control target when the detection signal indicates proximity of the signal source, The control system according to any one of Additional Notes 1 to 3 having

[0051] (Additional Note 5) The detector is An extractor that extracts an envelope of the oscillation signal, A low-pass filter that removes high-frequency components included in the extracted envelope, including The control system according to Additional Note 4.

[0052] (Appendix 6) At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source over time such that the ratio of the period during which the frequency difference from other signal sources is higher than the cut-off frequency of the low-pass filter is a certain value or more. The control system according to Appendix 5.

[0053] (Appendix 7) At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source at intervals of one-third or less of the reciprocal of the cut-off frequency of the low-pass filter. The control system according to Appendix 5 or Appendix 6.

[0054] (Appendix 8) The detector outputs, as the detection signal, a signal corresponding to the phase difference between the oscillation signal received by the first electrode and the oscillation signal received by a second electrode different from the first electrode. The control system according to Appendix 4.

[0055] (Appendix 9) When the detection signal indicates the proximity of the signal source, the controller decelerates or stops the movement of the movable part of the robot that is the control target, or changes the moving direction of the movable part. The control system according to any one of Appendices 4 to 8.

[0056] (Appendix 10) When the detection signal indicates the proximity of the signal source, the controller performs control to issue an alarm. The control system according to any one of Appendices 4 to 9.

[0057] (Appendix 11) When the detection signal indicates the proximity of the signal source, the controller performs control to cause the transmitter that is the control target to transmit an alarm signal to a receiver that is integrated with or separate from the signal source. The control system according to any one of Appendices 4 to 9.

[0058] (Appendix 12) A plurality of said signal sources are provided on a plurality of moving bodies The control system according to any one of Appendices 1 to 11

[0059] (Appendix 13) A plurality of said signal sources are provided on one moving body The control system according to any one of Appendices 1 to 11

Explanation of Reference Signs

[0060] 1 Control system 10 Robot 12 Movable part 20A, 20B Signal source 21 Operator 22 Moving body 30, 30A Control device 31, 31A Detector 32 Controller 33 Electrode 34 Amplifier 35 Extractor 36 Low-pass filter 41 First amplifier 42 Second amplifier 43 Phase shifter 44 Multiplier 45 Signal processor 46 First electrode 47 Second electrode

Claims

1. At least one signal source that outputs an oscillation signal, At least one control device that performs predetermined control on a control target when proximity of the signal source is detected, comprising At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source over time so that the frequency difference from other signal sources changes over time Control system.

2. At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source regularly or randomly The control system according to claim 1.

3. At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source by frequency hopping or frequency sweeping The control system according to claim 1.

4. The control device A detector that processes the input oscillation signal and outputs a detection signal corresponding to the distance from the signal source, A controller that performs predetermined control on a control target when the detection signal indicates proximity of the signal source, The control system according to any one of claims 1 to 3, having.

5. The detector An extractor that extracts the envelope of the oscillation signal, A low-pass filter that removes high-frequency components included in the extracted envelope, including The control system according to claim 4.

6. At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source over time so that the ratio of the period during which the frequency difference from other signal sources is higher than the cut-off frequency of the low-pass filter is a certain value or more The control system according to claim 5.

7. At least one of the signal sources changes the oscillation frequency of the oscillation signal output from the signal source at intervals of one-third or less of the reciprocal of the cut-off frequency of the low-pass filter The control system according to claim 5.

8. The detector outputs, as the detection signal, a signal corresponding to the phase difference between the oscillation signal received by the first electrode and the oscillation signal received by a second electrode different from the first electrode The control system according to claim 4.

9. When the detection signal indicates proximity of the signal source, the controller decelerates or stops the movement of the movable part of the robot that is the control target, or changes the moving direction of the movable part The control system according to claim 4.

10. When the detection signal indicates the proximity of the signal source, the controller performs control to issue an alarm. The control system according to claim 4. **Claim 11** When the detection signal indicates the proximity of the signal source, the controller performs control to cause the transmitter, which is the control target, to transmit an alarm signal toward a receiver that is integrated with or separate from the signal source. The control system according to claim 4. **Claim 12** A plurality of the signal sources are provided on a plurality of moving bodies. The control system according to any one of claims 1 to 3. **Claim 13** A plurality of the signal sources are provided on one moving body. The control system according to any one of claims 1 to 3.

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