Noise removal circuit and sensor

Abstract

A noise removal circuit for removing the influence of noise from data output by a sensor circuit is provided with: a wire routed so as to surround a cable; a noise detection circuit that generates a noise detection signal indicating the presence or absence of noise in the cable on the basis of the electric signal generated in the wire; and a data processing circuit that invalidates data in an invalidation period including at least a period in which the noise detection signal indicates that noise is generated among the data output from the sensor circuit.

Description

Technical Field

[0001] The present invention relates to a noise removal circuit and a sensor. Background Art

[0002] The motor for driving the robot arm is supplied with driving power by an inverter. The inverter is controlled by a PWM (Pulse Width Modulation) signal. The wiring that supplies the motor driving power after PWM control becomes a source of noise.

[0003] For example, there is known an AE measuring device for measuring AE generated from an object to be measured, comprising: a measuring AE sensor, which detects an AE signal generated from the object to be measured; an external noise AE sensor, which detects an external AE signal generated outside the object to be measured; a determination unit, which determines whether there is external noise based on the external AE signal detected by the external noise AE sensor; and a measurement processing unit, which, when an AE signal is detected in the measuring AE sensor, sets the AE signal to be valid if the determination unit determines that there is no external noise (for example, refer to patent document 1).

[0004] For example, a Rogowski-type current sensor is known, which has a plurality of coils connected continuously along a closed line, and a return line parallel to the closed line from the winding end of the last coil of the plurality of coils to the winding start side of the first coil, and detects a voltage induced between a terminal on the winding start side of the first coil and a terminal of the return line as a function of a current of a measured circuit inserted inside the closed line. The Rogowski-type current sensor is characterized in that each coil constituting the plurality of coils is formed on a plane orthogonal to the closed line, the winding end of one of the adjacent coils and the winding start of the next coil are connected by a forward line parallel to the closed line, and the forward line as a whole is arranged close to the return line (for example, refer to patent document 2).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-71945

[0008] Patent Document 2: International Publication No. 2017 / 014297 Summary of the invention

[0009] Problems to be solved by the invention

[0010] The noise caused by the motor drive power has an adverse effect on the accuracy of various sensors and the control of various devices. Therefore, it is extremely important to detect the noise and remove its influence. For example, a torque sensor for detecting torque is provided on the arm of a robot, and the noise caused by the motor drive power has an adverse effect on the accuracy of the torque sensor. The problem to be solved by the present disclosure is to realize a noise removal circuit for removing the influence of noise from data output by a sensor circuit and a sensor having the noise removal circuit.

[0011] Means for solving problems

[0012] According to one embodiment of the present disclosure, a noise removal circuit for removing the influence of noise from data output by a sensor circuit comprises: a conductor wired in a manner surrounding a cable; a noise detection circuit generating a noise detection signal indicating whether noise is generated in the cable based on an electrical signal generated in the conductor; and a data processing circuit invalidating data in an invalidation period including at least a period during which the noise detection signal indicates that noise is generated in the data output from the sensor circuit.

[0013] In addition, according to one embodiment of the present invention, the sensor includes: a sensor circuit that outputs data as a sensor detection result for an object; the above-mentioned noise removal circuit that removes the influence of noise from the data output by the sensor circuit; and a substrate that has an opening portion through which a cable passes, and the conductive wires are wired in a manner that surrounds the opening portion.

[0014] Effects of the Invention

[0015] According to one aspect of the present disclosure, it is possible to realize a noise removal circuit that removes the influence of noise from data output from a sensor circuit and a sensor having the noise removal circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a diagram showing a noise removal circuit according to an embodiment of the present disclosure and a torque sensor having the noise removal circuit.

[0017] Figure 2 It is a diagram showing a robot including a torque sensor according to an embodiment of the present disclosure.

[0018] Figure 3 This is a diagram illustrating the noise generated by the motor driving power flowing through the cable.

[0019] Figure 4 It is a perspective view showing a substrate of a first aspect of the torque sensor according to the embodiment of the present disclosure.

[0020] Figure 5 It is a perspective view showing a substrate of a second embodiment of the torque sensor according to the embodiment of the present disclosure.

[0021] Figure 6 It is a perspective view showing a substrate of a third form of the torque sensor according to the embodiment of the present disclosure.

[0022] Figure 7 : is a circuit diagram showing the configuration of a noise detection circuit in a noise removal circuit according to an embodiment of the present disclosure.

[0023] Figure 8 This is a waveform diagram for explaining the function of the noise detection circuit in the noise removal circuit according to the embodiment of the present disclosure.

[0024] Fig. 9 : is a waveform diagram illustrating a noise detection signal generated by a noise detection circuit in a noise removal circuit according to an embodiment of the present disclosure.

[0025] Fig.10 This is a waveform diagram (part 1) for explaining the setting of the filter of the noise detection circuit in the noise removal circuit according to the embodiment of the present disclosure.

[0026] Fig.11 This is a waveform diagram (part 2) for explaining the setting of the filter of the noise detection circuit in the noise removal circuit according to the embodiment of the present disclosure.

[0027] Fig.12 This is a waveform diagram for explaining the relationship between noise and data during the invalidation period in the embodiment of the present disclosure.

[0028] Fig.13 1 is a waveform diagram showing a first embodiment of data invalidation processing of a data processing circuit in a noise removal circuit according to an embodiment of the present disclosure.

[0029] Fig.14 1 is a waveform diagram showing a second embodiment of data invalidation processing of a data processing circuit in a noise removal circuit according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] Hereinafter, the noise removal circuit and the torque sensor of the embodiment will be described with reference to the accompanying drawings. In addition, in the following description, the same symbols are marked on the structures having the same or similar functions. In addition, the repeated description of these structures is sometimes omitted. In addition, in the following description, "connection" means "electrical connection".

[0031] <Overall structure of noise removal circuit and torque sensor>

[0032] Figure 1 : is a diagram showing a noise removal circuit according to an embodiment of the present disclosure and a torque sensor having the noise removal circuit. Figure 2It is a diagram showing a robot including a torque sensor according to an embodiment of the present disclosure.

[0033] According to an embodiment of the present disclosure, a torque sensor 100 includes a noise removal circuit 1, a sensor circuit 2, and a substrate 3 (in Figure 1 (not shown in the figure) In the present embodiment, as an example, the sensor circuit 2 is provided in the torque sensor 100 for detecting the torque of the object 300. As a modification thereof, the sensor circuit 2 may also be provided in a sensor other than the torque sensor. For example, the sensor circuit 2 may also be a sensor circuit that outputs electrical sensor data such as a current sensor, a voltage sensor, a magnetic sensor, a speed sensor, or a temperature sensor.

[0034] The torque sensor 100 is provided, for example, in the arm of the robot 1000. A noise removal circuit 1, a sensor circuit 2, and the like are provided on a substrate 3 of the torque sensor 100.

[0035] The sensor circuit 2 outputs data (hereinafter referred to as "sensor data") as a result of sensor detection of the object 300. Here, a torque sensor is used as an example, and therefore the sensor circuit 2 outputs sensor data related to the torque detected for the object 300. The object 300 as the object of torque detection is a motor that drives the arm of the robot. The sensor data output by the sensor circuit 2 may be analog data (analog signal) or digital data (digital signal).

[0036] The noise removal circuit 1 removes the influence of noise from the sensor data outputted from the sensor circuit 2. The noise removal circuit 1 includes a conductor 11, a noise detection circuit 12, and a data processing circuit 13.

[0037] An opening is provided in the substrate 3 of the torque sensor 100. The cable 200 through which the motor drive power after PWM control flows is arranged to penetrate the opening. The conductor 11 is routed to surround the opening on the substrate. Therefore, the conductor 11 is routed to surround the cable 200 which is a noise generation source caused by the motor drive power.

[0038] The noise detection circuit 12 generates a noise detection signal indicating whether or not noise is generated in the cable 200, based on the electrical signal generated in the conductive wire 11. The noise detection process performed by the noise detection circuit 12 will be described in detail later.

[0039] The data processing circuit 13 invalidates sensor data in an invalidation period including at least a period during which the noise detection signal indicates that noise has occurred, among sensor data outputted from the sensor circuit 2. Details of the data invalidation process by the data processing circuit 13 will be described later.

[0040] An operation processing device (processor) is provided in the torque sensor 100. Examples of the operation processing device include IC, LSI, CPU, MPU, DSP, etc. The data processing circuit 13 may be composed of only the operation processing device, or may be composed of a combination of an analog circuit and the operation processing device, or may be composed of only the analog circuit. For example, in the case where the data processing circuit 13 is constructed in the form of a software program, the function of the data processing circuit 13 can be realized by causing the operation processing device to operate according to the software program. Alternatively, it may be realized as a semiconductor integrated circuit in which a software program for realizing the function of the data processing circuit 13 is written. Alternatively, it may be realized as a recording medium in which a software program for realizing the function of the data processing circuit 13 is written.

[0041] Furthermore, the conductor 11 and the noise detection circuit 12 may be replaced with a Rogowski coil current detection circuit. In this case, the data processing circuit 13 is connected to the Rogowski coil current detection circuit, and the cable 200 is arranged to penetrate the opening of the substrate provided with the Rogowski coil.

[0042] <How noise is generated by motor drive power>

[0043] Figure 3 This is a diagram illustrating the noise generated by the motor driving power flowing through the cable.

[0044] The wiring for supplying the motor drive power after PWM control becomes a noise source. The motor drive power flowing through the cable 200 is a rectangular wave voltage. According to the change of the high and low of the rectangular wave voltage, a slight change of the magnetic field is generated around the cable 200, and noise is generated in the sensor data output by the sensor circuit 2 located near the cable 200. For example, Figure 3 As shown, at time t2 when the motor drive power switches from low to high and at time t4 when the motor drive power switches from high to low, a slight change in the magnetic field is generated around the cable 200 through which the motor drive power flows. As a result, noise is generated at time t2 and time t4 in the sensor data output by the sensor circuit 2 located near the cable 200.

[0045] Therefore, in the embodiment of the present disclosure, in order to detect the change of the magnetic field around the cable 200 in which the motor drive power flows, the conductor 11 is wired so as to surround the cable 200. Noise corresponding to the change of the motor drive power flowing in the cable 200 is generated in the conductor 11. The noise detection circuit 12 generates a noise detection signal indicating whether the noise is generated in the cable 200 based on the electrical signal related to the noise generated in the conductor 11.

[0046] <Structure of the board of the noise removal circuit>

[0047] Sometimes, an opening for passing various cables is provided in the substrate of the torque sensor 100 provided on the arm of the robot 1000. The cable 200 through which the motor driving power flows is also arranged to pass through the opening of the substrate. Therefore, in the embodiment of the present disclosure, the wire 11 is wired in a manner to surround the opening of the substrate 3 of the torque sensor 100, whereby the wire 11 surrounds the cable 200. In addition, as a modified example thereof, an opening may be provided in the frame of the torque sensor 100, the wire 11 may be wired in a manner to surround the opening of the frame of the torque sensor 100, and the cable 200 may be arranged to pass through the opening, whereby the wire 11 surrounds the cable 200.

[0048] Several examples of substrates are listed below.

[0049] Figure 4 It is a perspective view showing a substrate of a first aspect of the torque sensor according to the embodiment of the present disclosure.

[0050] The substrate 3 of the first embodiment has an annular shape with an opening 31 provided near the center of the disk-shaped substrate. The cable 200 passes through the opening 31. The substrate 3 includes a conductor 11 wired to surround the opening 31, a noise detection circuit 12, and a data processing circuit 13.

[0051] Figure 5 It is a perspective view showing a substrate of a second embodiment of the torque sensor according to the embodiment of the present disclosure.

[0052] The substrate 3 of the second embodiment has a C-shaped substrate with a cutout in a part of the circumferential direction, and an opening 31 is provided near the center. The cable 200 passes through the opening 31. The substrate 3 is provided with a conductor 11 wired in a C-shape so as to surround a part of the opening 31, a noise detection circuit 12, and a data processing circuit 13.

[0053] Figure 6 It is a perspective view showing a substrate of a third form of the torque sensor according to the embodiment of the present disclosure.

[0054] The substrate 3 of the third embodiment has an opening 31 provided near the center of the substantially quadrilateral substrate. The cable 200 passes through the opening 31. The substrate 3 includes a conductor 11 wired in a substantially quadrilateral shape surrounding the opening 31, a noise detection circuit 12, and a data processing circuit 13.

[0055] The first to third embodiments described above are examples, and any substrate shape and wiring shape other than those shown in the drawings may be used as long as the substrate is wired so that the conducting wires 11 surround the opening 31 through which the cable 200 passes.

[0056] <An example of the configuration of a noise detection circuit>

[0057] Figure 7 : is a circuit diagram showing the configuration of a noise detection circuit in a noise removal circuit according to an embodiment of the present disclosure.

[0058] As described above, the lead wire 11 and the data processing circuit 13 are connected to the noise detection circuit 12. The terminals P1 and P2 of the sensor circuit 2 are connected to a strain gauge whose resistance value changes according to the torque applied to the motor.

[0059] The noise detection circuit 12 includes a DC component adjustment section 21 , a threshold setting section 22 , a comparison section 23 , a wired OR connection section 24 , a filter 25 , and a buffer 26 .

[0060] The DC component adjustment unit 21 includes a capacitor 21-1 for removing a DC component from an electrical signal generated in the conductor 11, and resistors 21-2 and 21-3 for applying a predetermined DC component. In the DC component adjustment unit 21, the DC component is removed from the electrical signal generated in the conductor 11 by the capacitor 21-1, and the predetermined DC component is reapplied by the resistors 21-2 and 21-3. The voltage that becomes the reference when there is no noise is adjusted by the resistors 21-2 and 21-3 so as to converge between the upper threshold and the lower threshold set by the threshold setting unit 22 (hereinafter, sometimes referred to as the "threshold range").

[0061] The threshold setting section 22 , the comparison section 23 , the wired-OR connection section 24 , the filter 25 , and the buffer 26 constitute a noise detection signal generation section.

[0062] The threshold setting unit 22 is provided to set a threshold for detecting noise from the electrical signal generated in the conductor 11. The noise contained in the electrical signal generated in the conductor 11 is a vibration signal having a positive amplitude and a negative amplitude. In order to detect the noise, an upper threshold for comparison with the positive amplitude of the electrical signal and a lower threshold for comparison with the negative amplitude of the electrical signal are set by the threshold setting unit 22. The upper threshold is input to the inverting input (-) of the first comparator 23-1 constituting the comparison unit 23. The lower threshold is input to the non-inverting input (+) of the second comparator 23-2 constituting the comparison unit 23.

[0063] The comparison unit 23 compares a threshold value composed of an upper threshold value and a lower threshold value with the electric signal whose DC component has been adjusted by the DC component adjustment unit 21. Therefore, the comparison unit 23 includes a first comparator 23-1 and a second comparator 23-2.

[0064] The electrical signal whose DC component is adjusted by the DC component adjustment unit 21 is input to the in-phase input (+) of the first comparator 23-1, and the upper threshold is input to the inverting input (-). Through the first comparator 23-1, it is possible to detect whether the positive amplitude of the electrical signal whose DC component is adjusted by the DC component adjustment unit 21 exceeds the upper threshold. In addition, the electrical signal whose DC component is adjusted by the DC component adjustment unit 21 is input to the inverting input (-) of the second comparator 23-2, and the lower threshold is input to the in-phase input (+). Through the second comparator 23-2, it is possible to detect whether the negative amplitude of the electrical signal whose DC component is adjusted by the DC component adjustment unit 21 is lower than the lower threshold.

[0065] The signal output from the comparison section 23 (the first comparator 23-1 and the second comparator 23-2) is input to the wired OR connection section 24. The wired OR connection section 24 is provided to obtain the logical sum (OR) of the signal output when the first comparator 23-1 determines that the positive amplitude of the electric signal exceeds the upper threshold value and the signal output when the second comparator 23-2 determines that the negative amplitude of the electric signal is lower than the lower threshold value. By providing the wired OR connection section 24, it is possible to detect the occurrence of noise regardless of which of the case where the first comparator 23-1 determines that the positive amplitude of the electric signal exceeds the upper threshold value or the case where the second comparator 23-2 determines that the negative amplitude of the electric signal is lower than the lower threshold value occurs first.

[0066] The comparison unit 23 and the wired-OR connection unit 24 are formed of, for example, a reset IC.

[0067] The filter 25 and the buffer 26 have a function of suppressing jitter in the presence or absence of noise that may occur as a result of generating a noise detection signal based on comparison with a threshold value, thereby improving noise detection accuracy.

[0068] The noise detection circuit 12 has, for example, the above-mentioned structure, whereby, when it is determined that the electric signal generated by the conductor 11 is larger than the upper threshold or smaller than the lower threshold, that is, when the electric signal generated by the conductor 11 deviates from the threshold range between the upper threshold and the lower threshold, a noise detection signal indicating that noise is generated is generated and output. In addition, when it is determined that the electric signal generated by the conductor 11 is smaller than the upper threshold and larger than the lower threshold, that is, when the electric signal generated by the conductor 11 converges to the threshold range between the upper threshold and the lower threshold, the noise detection circuit 12 generates and outputs a noise detection signal indicating that no noise is generated. The noise detection signal, for example, indicates low when indicating that noise is generated, and indicates high when indicating that no noise is generated. The noise detection signal generated by the noise detection circuit 12 as described above is input to the data processing circuit 13.

[0069] <Function of noise detection circuit>

[0070] Figure 8This is a waveform diagram for explaining the function of the noise detection circuit in the noise removal circuit according to the embodiment of the present disclosure. Figure 8 In FIG. 1 , black circles represent sampling points of the sensor data output from the sensor circuit 2 of the torque sensor 100 by the data processing circuit 13. That is, the data processing circuit 13 samples the sensor data at time t5, time t6, time t7, time t8, time t9, and time t10. 10 and time t 11 , sampling the sensor data output from the sensor circuit 2.

[0071] If the torque sensor 100 is present near the cable 200 through which the motor drive power flows, noise will be generated in the sensor data output from the sensor circuit 2 of the torque sensor 100. Figure 8 In the example shown, noise is generated at time t7 and time t9. Assuming that the sensor data output from the sensor circuit 2 is directly monitored to detect the noise, the magnitude of the sensor data containing noise at time t7 and time t9 converges to the sensor data (maximum value) at time t6 without noise and the sensor data (maximum value) at time t7 without noise. 10 Therefore, it may not be possible to accurately distinguish between sensor data containing noise and normal sensor data not containing noise. In contrast, in the embodiment of the present disclosure, based on the electrical signal generated in the conductor 11 wired in a manner surrounding the cable 200, only the noise ( Figure 8 ), so the noise can be detected accurately.

[0072] <Relationship between noise detection signal and invalidation processing period>

[0073] Fig. 9 : is a waveform diagram illustrating a noise detection signal generated by a noise detection circuit in a noise removal circuit according to an embodiment of the present disclosure.

[0074] The electrical signal generated in the conductor 11 (at Figure 7 When the DC component of the electrical signal (in which the DC component is adjusted by the DC component adjustment unit 21) deviates from the threshold range, the noise detection circuit 12 generates a noise detection signal indicating that noise is generated. Fig. 9 In the example shown, at time t 12 The electrical signal input to the noise detection circuit 12 (i.e., the electrical signal generated in the wire 11) exceeds the upper threshold. Therefore, the noise detection circuit 12 12 At the time t after the predetermined period has passed 13During the period up to the output, a noise detection signal (low) indicating that noise is generated is output, and during the other periods, a noise detection signal (high) indicating that no noise is generated is output. The configuration of the inverter circuit and cable 200 that have an electrical impact on the torque sensor 100 provided in the robot 1000 has not changed significantly compared to when the robot was manufactured, so the noise contained in the electrical signal generated in the wire 11 is reproducible. Therefore, the time required from the generation of noise to the convergence of the noise is also approximately constant. Therefore, in an embodiment of the present disclosure, when the robot 1000 is developed, etc., the time required from the generation of noise to the convergence of the noise is measured in advance, and the time required from the generation of noise to the convergence of the noise is set based on the measured time. The constant of the filter 25 is determined based on the set time.

[0075] Fig.10 and Fig.11 This is a waveform diagram for explaining the setting of the filter of the noise detection circuit in the noise removal circuit according to the embodiment of the present disclosure.

[0076] like Fig.10 As shown in FIG. 1 , when the constant of the filter 25 is set to be weak, the magnitude relationship between the upper threshold value and the lower threshold value of the electric signal input to the noise detection circuit 12 (i.e., the electric signal generated in the wire 11) is reversed in a short time. Therefore, "jitter of the noise detection signal" occurs in which the noise detection signal (low) indicating the occurrence of noise and the noise detection signal (high) indicating the absence of noise are switched in a short time.

[0077] like Fig.11 As shown, when the constant of the filter 25 is set to a strong value, the noise detection circuit 12 outputs a noise detection signal (low) indicating that noise is generated because the electrical signal input to the noise detection circuit 12 (i.e., the electrical signal generated in the wire 11) exceeds the upper threshold value. 12 The time t at which the noise detection signal (high) indicating that no noise is generated is output 15 As a result, the data of the portion without noise is also unnecessarily invalidated.

[0078] Therefore, in an embodiment of the present disclosure, when developing the robot 1000, the time required from the generation of noise to the convergence of the noise is measured in advance, and the time required from the generation of noise to the convergence of the noise is set based on the measured time, and the appropriate constant of the filter 25 is determined based on the set time.

[0079] Fig.12 This is a waveform diagram for explaining the relationship between noise and data during the invalidation period in the embodiment of the present disclosure.

[0080] As reference Fig. 9As described above, the time point at which the electrical signal generated in the wire 11 deviates from the threshold range is time t 12 is the start point of the noise detection signal (low) indicating that noise is generated. However, in reality, from the time t 12 Since the time point before, noise that does not exceed the threshold has been generated. As described above, the noise contained in the electrical signal generated in the wire 11 has reproducibility. Therefore, in the embodiment of the present disclosure, when developing the robot 1000, the time required from the generation of noise to the electrical signal exceeding the threshold is measured in advance, and based on the measured time, the time point that is a predetermined time earlier than the starting point of the noise detection signal (low) indicating the generation of noise is set as the starting point of the invalidation period of the sensor data. Fig.12 In the example shown, the start point of the noise detection signal (low) indicating the occurrence of noise, i.e., time t 12 The previous moment t 14 Set as the starting point of the invalidation period of the sensor data. In addition, it is necessary to trace back to the starting point of the noise detection signal (low) indicating that noise is generated, that is, time t 12 The previous moment t 14 Therefore, the sensor data outputted from the sensor circuit 2 is temporarily stored in a storage unit (not shown) in the noise removal circuit 1, and the data processing circuit 13 performs processing to invalidate the sensor data stored in the storage unit during the invalidation period.

[0081] In order to simplify the structure and processing in the noise removal circuit 1, the start point of the noise detection signal (low) indicating the occurrence of noise, i.e., the time t 12 The sensor data invalidation period is set as the starting point. In this case, the sensor data does not need to be temporarily stored, so the storage unit can be omitted.

[0082] <Data invalidation processing of data processing circuit>

[0083] The data processing circuit 13 invalidates the sensor data in the invalidation period including at least the period during which the noise detection signal indicates the occurrence of noise, among the sensor data output from the sensor circuit 2. The following lists some data invalidation processes performed by the data processing circuit.

[0084] Fig.13 1 is a waveform diagram showing a first mode of data invalidation processing of a data processing circuit in a noise removal circuit according to an embodiment of the present disclosure. Fig.13In the example shown, as an example, the start point of the noise detection signal (low) indicating that noise is generated is set as the start point of the invalidation period of the sensor data. Alternatively, a time point that is a predetermined time earlier than the start point of the noise detection signal (low) indicating that noise is generated may be set as the start point of the invalidation period of the sensor data in the data processing circuit 13.

[0085] In the data invalidation process of the first embodiment, the data processing circuit 13 directly outputs the data output from the sensor circuit 2 during the period other than the invalidation period, and stops the output of the data output from the sensor circuit 2 during the invalidation period. Fig.13 In the example shown, at time t 17 To time t 18 The noise detection circuit 12 outputs a noise detection signal (low) indicating that noise is generated. Therefore, at time t 17 To time t 18 The output of the data output from the sensor circuit 2 is stopped during the invalidation period, and the data output from the sensor circuit 2 is directly output during the period other than the invalidation period. According to the data invalidation processing of the first embodiment, the influence of noise can be removed from the sensor data.

[0086] Fig.14 2 is a waveform diagram showing a second method of data invalidation processing by a data processing circuit in a noise removal circuit according to an embodiment of the present disclosure. Fig.14 In the middle, use S1~S 12 denoting the sampling points of the sensor data output from the sensor circuit 2 by the data processing circuit 13. Fig.14 In the example shown, as an example, the start point of the noise detection signal (low) indicating that noise is generated is set as the start point of the invalidation period of the sensor data. Alternatively, a time point that is a predetermined time earlier than the start point of the noise detection signal (low) indicating that noise is generated may be set as the start point of the invalidation period of the sensor data in the data processing circuit 13.

[0087] In the data invalidation process of the second mode, the data processing circuit 13 averages and outputs the values ​​represented by the sensor data output from the sensor circuit 2 during a predetermined period including the invalidation period, after invalidating the sensor data during the invalidation period among the sensor data output from the sensor circuit 2. Fig.14 In the example shown, from time t 19 At time t 20 During the period, from time t 21 At time t 22 During the period, and from time t 23 At time t 23 The sampling points S3, S7, S11 Then, the sensor data of the sampling points S1, S2, S4, S5, S6, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22, S23, S24, S25, S26, S27, S28, S29, S30, S31, S32, S33, S34, S35, S36, S37, S38, S39, S40, S41, S42, S43, S44, S45, S46, S47, S48, S49, S40, S41, S49, S41, S4 10 and S 12 The values ​​represented by the sensor data are averaged and output. The averaging time period can be set arbitrarily. For example, when the sensor data output from the sensor circuit 2 is an analog signal, jitter may occur in the value represented by the sensor data due to thermal noise or the like. However, according to the data invalidation processing of the second method, the influence of noise can be more reliably removed from the sensor data, and high-precision sensor data related to torque can be generated.

[0088] As described above, according to the embodiment of the present disclosure, the conductor 11 is wired around the cable 200 as a noise source, and the noise is detected based on the electrical signal generated in the conductor 11, so that the data portion affected by the noise in the sensor data output from the sensor circuit 2 is invalidated. With such a structure, it is possible to reliably remove abnormal values ​​affected by the noise from the sensor data output from the torque sensor 100 (the sensor circuit 2), and thus it is possible to generate high-precision sensor data related to the torque.

[0089] Generally speaking, the motor drive power after PWM control switches between high and low at a high speed, so the sensor data of the torque sensor located around the cable through which the motor drive power flows is easily affected by noise. For example, in the past, a measure was taken to reduce the influence of noise by taking the time average of the sensor data, but there was a problem of loss of high-speed sensor processing. In contrast, according to the embodiment of the present disclosure, the data part affected by noise in the sensor data output from the sensor circuit 2 is invalidated, so that the high-speed sensor processing can be ensured.

[0090] In addition, if the sensor data output from the sensor circuit is directly monitored to directly detect noise, the size of the sensor data containing noise converges between the maximum value of the sensor data not containing noise and the minimum value of the sensor data not containing noise. Therefore, it may not be possible to accurately distinguish the sensor data containing noise from the normal sensor data not containing noise. In contrast, in the embodiment of the present disclosure, only noise is detected by the noise detection circuit 12 based on the electrical signal generated in the conductor 11 wired in a manner surrounding the cable 200, so that the noise can be accurately detected.

[0091] In addition, sometimes an opening for passing various cables is provided on the substrate of the torque sensor 100 provided on the arm of the robot. In the embodiment of the present disclosure, the conductor 11 is wired in a manner surrounding the opening of the substrate 3 of the torque sensor 100, so that the noise removal circuit can be easily installed in the conventional torque sensor.

[0092] <Modifications and Alternative Examples of Embodiments>

[0093] In the above-described embodiment, the noise detection signal is low when noise is generated and high when no noise is generated. As an alternative, the noise detection signal may be high when noise is generated and low when no noise is generated.

[0094] In addition, in the above-described embodiment, the cable 200 is set as a power cable through which the motor drive power flows. As a modification thereof, the cable 200 may also be a cable other than the power cable through which the motor drive power flows. For example, the cable 200 may also be a signal cable through which a PWM signal used to control an inverter flows, or a power cable through which the power supply power flows.

[0095] In addition, in the above-described embodiment, the sensor circuit 2 is provided in the torque sensor 100 for detecting the torque of the object 300. As a modification thereof, the sensor circuit 2 may also be provided in a sensor other than the torque sensor. For example, the sensor circuit 2 may also be a sensor circuit that outputs electrical sensor data such as a current sensor, a voltage sensor, a magnetic sensor, a speed sensor, or a temperature sensor.

[0096] The embodiments of the present disclosure are described in detail, but the present disclosure is not limited to the above-mentioned embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. without departing from the scope of the main purpose of the invention, or without departing from the scope of the main purpose of the present invention derived from the contents recorded in the scope of the patent protection requested and its equivalents. For example, in the above-mentioned embodiments, the order of each action and the order of each processing are shown as an example and are not limited to this. In addition, the same is true for the case where numerical values ​​or mathematical formulas are used in the description of the above-mentioned embodiments.

[0097] Explanation of symbols

[0098] 1Noise removal circuit,

[0099] 2 sensor circuit,

[0100] 3 substrate,

[0101] 11 wires,

[0102] 12Noise detection circuit,

[0103] 13. Data processing circuit,

[0104] 21 DC component adjustment unit,

[0105] 21-1 capacitor,

[0106] 21-2, 21-3 resistors,

[0107] 22threshold setting unit,

[0108] 23Comparative Department,

[0109] 23-1 First Comparator

[0110] 23-2 Second comparator,

[0111] 24 wires or connectors,

[0112] 25 filters,

[0113] 26 buffers,

[0114] 31 opening,

[0115] 100 torque sensor,

[0116] 200 cables,

[0117] 300 objects,

[0118] 1000 robots.

Claims

1. A noise removal circuit for removing the influence of noise from data output by a sensor circuit, characterized in that: The noise removal circuit has: Conductors, which are routed in such a way as to surround the cable; A noise detection circuit, which generates a noise detection signal indicating whether noise is generated in the cable according to the electrical signal generated in the conductor; as well as A data processing circuit invalidates data in an invalidation period including at least a period during which the noise detection signal indicates that noise has occurred, among the data output from the sensor circuit.

2. The noise removal circuit according to claim 1, characterized in that: The data processing circuit directly outputs the data output from the sensor circuit during a period other than the invalidation period, and stops outputting the data output from the sensor circuit during the invalidation period.

3. The noise removal circuit according to claim 1, characterized in that: The data processing circuit averages and outputs values ​​represented by data output from the sensor circuit in a predetermined period including the invalidation period, after invalidating data in the invalidation period among the data output from the sensor circuit.

4. The noise removal circuit according to any one of claims 1 to 3, characterized in that: A time point that is a predetermined time period before a period during which the noise detection signal indicates that noise is generated is set as a start point of the invalidation period.

5. The noise removal circuit according to any one of claims 1 to 4, characterized in that: The noise detection circuit has: a DC component adjustment unit that adjusts a DC component from an electrical signal generated from the conductor; as well as The noise detection signal generating unit generates and outputs the noise detection signal indicating that noise has occurred, when it is determined that the amplitude of the electrical signal whose DC component has been adjusted by the DC component adjusting unit deviates from a predetermined threshold range.

6. A sensor, characterized in that: have: a sensor circuit that outputs data as a result of sensor detection of an object; The noise removal circuit according to any one of claims 1 to 5, which removes the influence of noise from the data output by the sensor circuit; as well as The substrate has an opening through which the cable passes, and the conductive wire is routed so as to surround the opening.

7. The sensor according to claim 6, characterized in that The sensor circuit and the noise removal circuit are provided on the substrate.

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