Noise reduction circuit and sensor

Abstract

This noise suppression circuit, which removes the effect of noise from the data output by a sensor circuit, comprises: a conductor wire surrounding an electrical cable; a noise detection circuit for generating a noise detection signal that indicates the presence or absence of noise in the electrical cable based on the electrical signal generated in the conductor wire; and a data processing circuit that invalidates the data output by the sensor circuit during an invalidation period that includes at least one period in which the noise detection signal indicates that noise has occurred.

Description

TECHNICAL FIELD

[0001] The present invention relates to a noise suppression circuit and a sensor. STATE OF THE ART

[0002] A motor used to drive a robot arm is supplied with drive power by an inverter. The inverter is controlled based on a pulse-width modulation (PWM) signal. A wiring line that supplies the motor with PWM-controlled drive power is a source of interference.

[0003] For example, an AE measuring device is known that measures an AE generated by a measured object and includes: an AE measurement sensor that detects an AE signal generated by the measured object; an AE external noise sensor that detects an external AE signal generated outside the measured object; a determination unit configured to determine whether external noise is present based on the external AE signal detected by the AE external noise sensor; and a measurement processing unit configured to validate the AE signal in a case where the determination unit determines that there is no external noise when the AE signal is detected by the AE measurement sensor (see, for example, PTL 1).

[0004] For example, a Rogowski current sensor is known which includes a return path continuously connecting a plurality of coils along a closed line and is provided in parallel with the closed line from a winding end of a last coil of the plurality of coils to a winding start side of a first coil, and which detects a voltage induced between a winding start terminal of the first coil and a terminal of the return path as a function of a current in a measuring circuit introduced through the closed line, each coil forming the plurality of coils is formed on a plane perpendicular to the closed line, a winding end of a particular coil and a winding start of a next coil of adjacent coils are connected by an outgoing conduction path provided in parallel with the closed line,and the entire outgoing conduction path and the return conduction path are arranged nearby (see, for example, PTL 2). [CITATION LIST][PATENT LITERATURE] [PTL 1] JP 2010-71945A [PTL 2] WO2017 / 014297A1 SUMMARY OF THE INVENTION [TECHNICAL PROBLEM]

[0005] Noise caused by the drive power of motors negatively affects the accuracy of various sensors, the control of various devices, and the like. Therefore, it is extremely important to detect noise and eliminate the influence of noise. For example, a torque sensor is provided for detecting the torque on an arm of a robot, and the noise due to the motor drive power negatively affects the accuracy of the torque sensor. The problem to be solved by the present disclosure is to provide a noise reduction circuit that removes the influence of noise from the data output by a sensor circuit and to provide a sensor that includes the noise reduction circuit. (SOLUTION OF THE PROBLEM)

[0006] According to one aspect of the present disclosure, a noise suppression circuit configured to remove an influence of noise from data output from a sensor circuit includes: a lead wire wired to surround an electrical cable; a noise detection circuit configured to generate a noise detection signal indicating the occurrence or non-occurrence of noise in the electrical cable based on an electrical signal generated in the lead wire; and a data processing circuit configured to invalidate data during an invalidation period including at least a period in which the noise detection signal indicates the occurrence of noise among the data output from the sensor circuit.

[0007] According to one aspect of the present disclosure, a sensor further comprises: a sensor circuit configured to output data that is a sensor detection result of a target object; the above-described noise suppression circuit configured to remove an influence of noise from the data output from the sensor circuit; and a printed circuit board having an opening through which the electrical cable passes and on which the lead wire is wired to surround the opening. [ADVANTAGEOUS EFFECTS OF THE INVENTION]

[0008] An aspect of the present disclosure can achieve a noise suppression circuit configured to remove an influence of noise from data output from a sensor circuit, and a sensor including the noise suppression circuit. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a noise suppression circuit according to an embodiment of the present disclosure and a torque sensor having this noise suppression circuit. Fig. 2 is a diagram showing a robot with a torque sensor according to the present disclosure. Fig. Figure 3 is a graph illustrating noise caused by motor drive power flowing through an electrical cable. Fig. 4 is a perspective view showing a printed circuit board in a first aspect of the torque sensor according to the embodiment of the present disclosure. Fig. 5 is a perspective view showing the printed circuit board in a second aspect of the torque sensor according to the embodiment of the present disclosure. Fig. 6 is a perspective view showing the printed circuit board in a third aspect of the torque sensor according to the embodiment of the present disclosure. Fig. 7 is a circuit diagram showing a configuration of a noise detection circuit in the noise suppression circuit according to the embodiment of the present disclosure. Fig. 8 is a waveform diagram showing a function of the noise detection circuit in the noise reduction circuit according to the embodiment of the present disclosure. Fig. 9 is a waveform diagram showing a noise detection signal generated by the noise detection circuit in the noise suppression circuit according to the embodiment of the present disclosure. Fig. 10 is a waveform diagram (part 1) showing the setting of a filter by the noise detection circuit in the noise reduction circuit according to the embodiment of the present disclosure. Fig. 11 is a waveform diagram (part 2) showing the adjustment of the filter by the noise detection circuit in the noise reduction circuit according to the embodiment of the present disclosure. Fig. 12 is a waveform diagram illustrating the relationship between noise and data in an invalid period in the embodiment of the present disclosure. Fig. 13 is a waveform diagram showing invalidated data processing in a first aspect of a data processing circuit in the noise suppression circuit according to the embodiment of the present disclosure. Fig. 14 is a waveform diagram showing data invalidation processing in a second aspect of the data processing circuit in the noise suppression circuit according to the embodiment of the present disclosure. DESCRIPTION OF THE EMBODIMENTS

[0009] A noise suppression circuit and a torque sensor according to an embodiment will be described below with reference to the drawings. Note that a component having the same or similar function is denoted by the same reference numeral in the following description. In this case, overlapping descriptions of the components may be omitted. Furthermore, "connected" in the following description means "electrically connected." <Gesamtkonfiguration des Schaltkreises zur Rauschunterdrückung und des Drehmomentsensors>

[0010] Fig. 1 is a diagram showing a noise suppression circuit according to an embodiment of the present disclosure and a torque sensor having the noise suppression circuit. Fig. 2 is a diagram showing a robot with a torque sensor according to the present embodiment.

[0011] According to the present embodiment, a torque sensor 100 comprises a noise reduction circuit 1, a sensor circuit 2 and a printed circuit board 3 (in Fig. 1 (not shown). In the present embodiment, as an example, it is assumed that the sensor circuit 2 is provided in the torque sensor 100 that detects the torque of a target object 300. As a modification example, the sensor circuit 2 may also be provided in a sensor other than a torque sensor. For example, the sensor circuit 2 may be a sensor circuit configured to output electrical sensor data from a current sensor, a voltage sensor, a magnetic sensor, a speed sensor, a temperature sensor, and the like.

[0012] The torque sensor 100 is installed, for example, in an arm of a robot 1000. The printed circuit board 3 of the torque sensor 100 is equipped with a noise reduction circuit (1), a sensor circuit (2), and the like.

[0013] The sensor circuit 2 outputs data (hereinafter referred to as "sensor data") that is a sensor data acquisition result of the target object 300. A torque sensor is used as an example here, and therefore the sensor circuit 2 outputs sensor data about the torque detected by the target object 300. The target object 300, which serves as the target of torque acquisition, is a motor that drives a robot arm. The sensor data output by the sensor circuit 2 can be analog data (analog signal) or digital data (digital signal).

[0014] The noise reduction circuit 1 removes the influence of noise from the sensor data output by the sensor circuit 2. The noise reduction circuit 1 includes a lead wire 11, a noise detection circuit 12, and a data processing circuit 13.

[0015] The printed circuit board 3 of the torque sensor 100 has an opening. The electrical cable 200, through which the motor drive power subject to PWM control flows, is routed through the opening. The lead wire 11 is wired to surround the opening on the printed circuit board. Thus, the lead wire 11 is wired to surround the electrical cable 200, which is a source of noise due to the motor drive power.

[0016] The noise detection circuit 12 generates a noise detection signal indicating the presence or absence of noise in the electrical cable 200 based on an electrical signal generated in the conductor wire 11. Details of the noise detection processing by the noise detection circuit 12 are described below.

[0017] The data processing circuit 13 invalidates the sensor data during an invalidation period, which includes at least a period in which the noise detection signal indicates the occurrence of noise in the sensor data output by the sensor circuit 2. Details of the data invalidation processing by the data processing circuit 13 are described below.

[0018] An arithmetic processing device (processor) is provided in the torque sensor 100. Examples of arithmetic processing devices include an IC, an LSI, a CPU, an MPU, a DSP, and the like. The data processing circuit 13 may be composed of only the arithmetic processing device, a combination of an analog circuit and the arithmetic processing device, or only the analog circuit. For example, if the data processing circuit 13 is implemented as a software program, the arithmetic processing device executes a movement according to the software program, thus achieving a function of the data processing circuit 13. Alternatively, the data processing circuit 13 may be implemented as a semiconductor integrated circuit in which a software program that fulfills the function of the data processing circuit 13 is written.Alternatively, the data processing circuit 13 may be implemented as a recording medium into which a software program is written that performs the function of the data processing circuit 13.

[0019] It should be noted that the lead wire 11 and the noise detection circuit 12 can be replaced by a current detection circuit in a Rogowski coil system. In this case, the current detection circuit in the Rogowski coil system is connected to the data processing circuit 13, and the electrical cable 200 is also routed through the opening of the printed circuit board equipped with a Rogowski coil. <Prinzip des Auftretens von Rauschen durch Motorantriebsleistung>

[0020] Fig. Figure 3 is a graph illustrating noise caused by the motor drive power flowing through the electrical cable.

[0021] A wiring line that supplies motor drive power subject to PWM control is a source of noise. The motor drive power flowing through the electrical cable 200 is a square-wave voltage, and a minute change in a magnetic field occurs around the electrical cable 200 in accordance with a change in the high and low values ​​of the square-wave voltage, and noise occurs in the sensor data output from the sensor circuit 2 located near the electrical cable 200. As shown in Fig. For example, as shown in Figure 3, at a time t2 when the motor drive power is switched from low to high, and at a time t4 when the motor drive power is switched from high to low, a minute change occurs in the magnetic field around the electric wire 200 through which the motor drive power flows. As a result, noise occurs in the sensor data output from the sensor circuit 2 near the electric wire 200 at time t2 and time t4.

[0022] In the present embodiment, the lead wire 11 is wired to surround the electric cable 200 to detect a change in the magnetic field around the electric cable 200 through which the motor drive power flows. Depending on a change in the motor drive power flowing through the electric cable 200, noise is generated in the lead wire 11. The noise detection circuit 12 generates a noise detection signal indicating the presence or absence of noise in the electric cable 200 based on an electrical signal related to the noise occurring in the lead wire 11. <Struktur der gedruckten Schaltkreisplatine der Entstörungsschaltkreis>

[0023] The printed circuit board of the torque sensor 100 provided in the arm of the robot 1000 may have an opening for passing various cables. The electric cable 200 through which the drive power of the motor flows is also passed through the opening of the printed circuit board. Therefore, in the present embodiment, the lead wire 11 is wired to surround the opening of the printed circuit board 3 of the torque sensor 100, and thus the lead wire 11 surrounds the electric cable 200. It should be noted that, as a modification example, an opening may be provided in a housing of the torque sensor 100, the lead wire 11 may be wired to surround the opening of the housing of the torque sensor 100, the electric cable 200 may be arranged through the opening, and thus the lead wire 11 may surround the electric cable 200.

[0024] Below are some examples of aspects of the printed circuit board.

[0025] Fig. 4 is a perspective view showing the printed circuit board in a first aspect of the torque sensor according to the embodiment of the present disclosure.

[0026] The printed circuit board 3 of the first aspect has a ring shape formed through an opening 31 near the center of a disk-shaped printed circuit board. The electrical cable 200 passes through the opening 31. The lead wire 11, which is wired to surround the opening 31, the noise detection circuit 12, and the data processing circuit 13 are provided on the printed circuit board 3.

[0027] Fig. 5 is a perspective view showing the printed circuit board in a second aspect of the torque sensor according to the embodiment of the present disclosure.

[0028] The printed circuit board 3 in the second aspect has a shape achieved by providing the opening 31 near the center of a C-shaped printed circuit board with a notch in a part in a circumferential direction. The electric cable 200 is passed through the opening 31. The lead wire 11, which is wired in a C-shape to surround a part of the opening 31, the noise detection circuit 12, and the data processing circuit 13 are provided on the printed circuit board 3.

[0029] Fig. 6 is a perspective view showing the printed circuit board in a third aspect of the torque sensor according to the embodiment of the present disclosure.

[0030] The printed circuit board 3 of the third aspect has a shape achieved by providing the opening 31 near the center of a substantially square printed circuit board. The electric cable 200 passes through the opening 31. The lead wire 11, which is wired in a substantially square shape to surround the opening 31, the noise detection circuit 12, and the data processing circuit 13 are provided on the printed circuit board 3.

[0031] The first to third aspects described above are an example, and a printed circuit board shape and a wiring shape other than the illustrated shapes may be used as long as a printed circuit board in which the lead wire 11 is wired to surround the opening 31 through which the electric cable 200 passes is used. <Ein Beispiel für die Konfiguration eines Schaltkreises zur Rauscherkennung>

[0032] Fig. 7 is a circuit diagram showing a configuration of the noise detection circuit in the noise reduction circuit according to the embodiment of the present disclosure.

[0033] As described above, the lead wire 11 and the data processing circuit 13 are connected to the noise detection circuit 12. A strain gauge with a resistance value that changes with the torque applied to a motor is connected to terminals P1 and P2 of the sensor circuit 2.

[0034] The noise detection circuit 12 includes a DC component adjustment unit 21, a threshold adjustment unit 22, a comparison unit 23, a wired OR connection unit 24, a filter 25, and a buffer 26.

[0035] The DC component adjustment unit 21 includes a capacitor 21-1 configured to remove a DC component from an electrical signal generated in the conducting wire 11, and resistors 21-2 and 21-3 configured to apply a defined DC component. In the DC component adjustment unit 21, a DC component is removed from an electrical signal generated in the conducting wire 11 by the capacitor 21-1, and a predetermined DC component is reapplied using the resistors 21-2 and 21-3. A voltage serving as a reference in the absence of noise is adjusted by the resistors 21-2 and 21-3 to be between an upper threshold and a lower threshold (hereinafter referred to as the "threshold range") set in the threshold adjustment unit 22.

[0036] The threshold setting unit 22, the comparison unit 23, the wired OR connection unit 24, the filter 25 and the buffer 26 constitute a noise detection signal generation unit.

[0037] The threshold setting unit 22 is used to set a threshold for detecting noise in an electrical signal generated in the conducting wire 11. The noise contained in the electrical signal generated in the conducting wire 11 is an oscillation signal with a positive amplitude and a negative amplitude. To detect the noise, an upper threshold used for comparison with a positive amplitude of the electrical signal and a lower threshold used for comparison with a negative amplitude of the electrical signal are set by the threshold setting unit 22. The upper threshold is input to an inverted input (-) of a first comparator 23-1, which forms the comparison unit 23.The lower threshold value is input to a non-inversion input (+) of a second comparator 23-2, which forms the comparison unit 23.

[0038] The comparison unit 23 compares a threshold value formed from the upper threshold value and the lower threshold value with an electrical signal having a DC component adjusted by the DC component adjustment unit 21. Thus, the comparison unit 23 comprises the first comparator 23-1 and the second comparator 23-2.

[0039] An electrical signal with a DC component adjusted by the DC component adjusting unit 21 is input to the non-inverting input (+) of the first comparator 23-1, and the upper threshold is input to the inverting input (-). Whether a positive amplitude of the electrical signal with the DC component adjusted by the DC component adjusting unit 21 exceeds the upper threshold can be detected by the first comparator 23-1. Further, an electrical signal with a DC component controlled by the DC component adjusting unit 21 is input to the inverting input (-) of the second comparator 23-2, and the lower threshold is input to the non-inverting input (+).Whether a negative amplitude of the electrical signal with the DC component adjusted by the DC component adjusting unit 21 falls below the lower threshold can be detected by the second comparator 23-2.

[0040] A signal output from the comparison unit 23 (the first comparator 23-1 and the second comparator 23-2) is input to the wired OR connection unit 24. The wired OR connection unit 24 is used to form a logical sum (OR) of an output signal when the first comparator 23-1 determines that a positive amplitude of an electrical signal exceeds the upper threshold and an output signal when the second comparator 23-2 determines that a negative amplitude of an electrical signal falls below the lower threshold.With the wired OR connection unit 24, the occurrence of noise can be detected even if either the case where it is determined by the first comparator 23-1 that a positive amplitude of an electrical signal exceeds the upper threshold value or the case where it is determined by the second comparator 23-2 that a negative amplitude of an electrical signal falls below the lower threshold value occurs first.

[0041] The comparison unit 23 and the wired OR connection unit 24 are formed, for example, by a reset IC.

[0042] The filter 25 and the buffer 26 have the function of suppressing fluctuations in the occurrence or non-occurrence of noise that may occur as a result of generating a noise detection signal based on a comparison with a threshold value and improving the accuracy of noise detection.

[0043] For example, with the configuration described above, if it is determined that an electrical signal generated in the conducting wire 11 is greater than the upper threshold or less than the lower threshold, that is, if an electrical signal generated in the conducting wire 11 is outside the threshold range between the upper threshold and the lower threshold, the noise detection circuit 12 generates and outputs a noise detection signal indicating the occurrence of noise. Further, if it is determined that an electrical signal generated in the conducting wire 11 is less than the upper threshold and greater than the lower threshold, that is,When an electrical signal generated in the conducting wire 11 falls within the threshold range between the upper threshold and the lower threshold, the noise detection circuit 12 generates and outputs a noise detection signal indicating the absence of noise. For example, the noise detection signal indicates "Low" when noise is detected, and the noise detection signal indicates "High" when noise is detected. The noise detection signal generated in the noise detection circuit 12 as described above is input to the data processing circuit 13. <Funktion des Schaltkreises zur Rauscherkennung>

[0044] Fig. 8 is a waveform diagram showing a function of the noise detection circuit in the noise reduction circuit according to the embodiment of the present disclosure. Fig. Fig. 8 illustrates, by a black dot, a sampling point by the data processing circuit 13 for the sensor data output from the sensor circuit 2 of the torque sensor 100. In other words, the data processing circuit 13 samples the sensor data output from the sensor circuit 2 at a time t5, a time t6, a time t7, a time t8, a time t9, a time t 10 and a time t 11 away.

[0045] When the torque sensor 100 is located near the electric cable 200 through which the drive power of the motor flows, noise occurs in the sensor data output from the sensor circuit 2 of the torque sensor 100. In the Fig. In the example shown in Figure 8, for example, the noise occurs at time t7 and time t9. If the noise is to be directly detected by monitoring the sensor data output by the sensor circuit 2, a value of the sensor data with noise at time t7 and time t9 falls between the sensor data (maximum value) at time t6 without noise and the sensor data (minimum value) at time t 10 without noise. Therefore, there is a possibility that the sensor data with noise and the normal sensor data without noise cannot be accurately distinguished. In contrast, in the present embodiment, only noise is detected by the noise detection circuit 12 based on an electrical signal generated in the lead wire 11 wired to surround the electrical cable 200 (the lower waveform diagram in Fig. 8), and thus noise can be accurately detected. <Beziehung zwischen Rauscherkennungssignal und Verarbeitungszeit für die Ungültigkeitserklärung>

[0046] Fig. 9 is a waveform diagram showing a noise detection signal generated by the noise detection circuit in the noise suppression circuit according to the embodiment of the present disclosure.

[0047] When an electrical signal generated in the lead wire 11 (electrical signal with a DC component which is converted into Fig. 7) is outside a threshold range, the noise detection circuit 12 generates a noise detection signal indicating the occurrence of noise. Fig. In the example shown in Figure 9, an electrical signal input to the noise detection circuit 12 (i.e., an electrical signal generated in the conducting wire 11) exceeds an upper threshold at a time t 12 . Therefore, the noise detection circuit 12 outputs a noise detection signal (Low) indicating the occurrence of noise during a period from time t 12 until a time t 13after a predetermined period has elapsed, and the noise detection circuit 12 outputs a noise detection signal (High) indicating the absence of noise during the other period. An arrangement of an inverter circuit and the electric cable 200, which have an electrical influence on the torque sensor 100 provided in the robot 1000, does not change significantly from the time of manufacture of a robot, and thus the noise contained in an electrical signal generated in the lead wire 11 has reproducibility. Thus, the time required from the occurrence of the noise until the noise is suppressed is also fixed.Therefore, in the present embodiment of the present disclosure, the time required from the occurrence of noise until the noise is suppressed is measured in advance at a time of development of the robot 1000 and the like, and the time required from the occurrence of noise until the noise is suppressed is set based on the measured time. A constant of the filter 25 is determined based on the set time.

[0048] Fig. 10 and Fig. 11 are waveform diagrams illustrating the adjustment of the filter by the noise detection circuit in the noise reduction circuit according to the embodiment of the present disclosure.

[0049] As in Fig. As shown in Figure 10, when a constant of the filter 25 is set to be weak, a magnitude relationship between the upper threshold and the lower threshold in an electrical signal input to the noise detection circuit 12 (i.e., an electrical signal generated in the lead wire 11) is reversed in a short time. Thus, "fluctuations in a noise detection signal" occur, in which the noise detection signal (Low) indicating the presence of noise and the noise detection signal (High) indicating the absence of noise are switched in a short time.

[0050] As in Fig. 11, when a constant of the filter 25 is set to be strong, a period of time t 12at which an electrical signal input to the noise detection circuit 12 (ie, an electrical signal generated in the lead wire 11) exceeds the upper threshold and the noise detection signal (Low) indicating the occurrence of noise is thus output, until a time t 15 The time at which the noise detection signal (High), indicating the absence of noise, is output is long. As a result, even data representing a noise-free portion is degraded more than necessary.

[0051] Therefore, in the present embodiment of the present disclosure, the time required from the occurrence of the noise until the noise is suppressed is measured in advance at a time of development of the robot 1000 and the like, the time required from the occurrence of the noise until the noise is suppressed is set based on the measured time, and an appropriate constant of the filter 25 is determined based on the set time.

[0052] Fig. 12 is a waveform diagram illustrating the relationship between noise and data in an invalid period in the embodiment of the present disclosure.

[0053] As in Fig. 9, the time t 12, which is a time at which an electrical signal generated in the conducting wire 11 is outside the threshold range, is a starting point of the noise detection signal (Low), indicating the occurrence of noise. However, noise to the extent that a threshold is not exceeded actually occurs since a time before time t 12which is the starting point of the noise detection signal. As described above, the noise contained in the electrical signal generated in the lead wire 11 is reproducible. Therefore, in the embodiment of the present disclosure, the time required from the occurrence of noise until the electrical signal exceeds a threshold is measured in advance at a time point of development of the robot 1000 and the like, and a time point that is a predetermined time before the starting point of the noise detection signal (Low) indicating the occurrence of noise is set as a starting point of an invalid period of sensor data based on the measured time. In the Fig. In the example shown in Figure 12, a time t 14 before time t 12, which is the starting point of the noise detection signal (Low) indicating the occurrence of noise, is set as the starting point of the invalid period of the sensor data. It should be noted that the invalid period of the sensor data at time t 14 before time t 12 must be executed, which is the starting point of the noise detection signal (Low) indicating the occurrence of noise. Therefore, the sensor data output from the sensor circuit 2 is temporarily held in a storage unit (not shown) in the noise suppression circuit 1, and the data processing circuit 13 performs processing on the sensor data held in the storage unit to invalidate the sensor data during the invalidation period.

[0054] To simplify the configuration and processing in the noise suppression circuit (1), the time t 12, which is the starting point of the noise detection signal (Low) indicating the occurrence of noise, can be set as the starting point for the invalidation period of the sensor data. In this case, the sensor data does not need to be temporarily stored, and the storage unit can thus be omitted. <Ungültigkeitserklärung von Daten durch den Schaltkreis zur Datenverarbeitung>

[0055] The data processing circuit 13 invalidates the sensor data during the invalidation period, which includes at least a period in which the noise detection signal indicates the occurrence of noise in the sensor data output by the sensor circuit 2. The following are some examples of data invalidation processing by the data processing circuit.

[0056] Fig. 13 is a waveform diagram showing the data invalidation processing in a first aspect of the data processing circuit in the noise suppression circuit according to the embodiment of the present disclosure. In the Fig. In the example shown in Figure 13, as an example, a starting point of the noise detection signal (Low) indicating the occurrence of noise is set as the starting point of the invalid period of the sensor data. Note that a time point a predetermined time before the starting point of the noise detection signal (Low) indicating the occurrence of noise may be set as the starting point of the invalid period of the sensor data in the data processing circuit 13.

[0057] In the data invalidation processing of the first aspect, the data processing circuit 13 outputs data output from the sensor circuit 2 during a period other than the invalidation period, and stops outputting the data output from the sensor circuit 2 during the invalidation period. In the Fig. In the example shown in Figure 13, the noise detection signal (Low), which indicates the occurrence of noise, is output by the noise detection circuit 12 from a time t 17 up to a time t 18 output, and thus an output of the data output from the sensor circuit 2 during the invalid period from the time t 17 until time t 18stopped, and the data output from the sensor circuit 2 is output as it is during a period other than the invalidation period. The data invalidation processing in the first aspect can remove the influence of noise from the sensor data.

[0058] Fig. 14 is a waveform diagram illustrating data invalidation processing in a second aspect of the data processing circuit in the noise suppression circuit according to the embodiment of the present disclosure. Fig. 14 shows as S1 to S 12 Sampling points by the data processing circuit 13 for the sensor data output by the sensor circuit 2. In the Fig. In the example shown in Figure 14, as an example, a starting point of the noise detection signal (Low) indicating the occurrence of noise is set as the starting point of the invalid period of the sensor data. Note that a time point a predetermined time before the starting point of the noise detection signal (Low) indicating the occurrence of noise may be set as the starting point of the invalid period of the sensor data in the data processing circuit 13.

[0059] In the data invalidation processing in the second aspect, the data processing circuit 13 invalidates the sensor data during the invalidation period among the sensor data output from the sensor circuit 2, and then averages and outputs the values ​​indicated by the sensor data output from the sensor circuit 2 during a predetermined period including the invalidation period. Fig. In the example shown in Figure 14, the sensor data at the sampling points S3, S7 and S 11 from a time t 19 up to a time t 20 , from a time t 21 up to a time t 22 and from a time t 23 up to a time t 23 invalidated. Then, the values ​​obtained from the sensor data at sampling points S1, S2, S4, S5, S6, S8, S9, S 10 and S 12displayed during a period other than the invalidation period are averaged and output. The time and period for which the averaging is performed can be freely set. For example, when the sensor data output from the sensor circuit 2 is an analog signal, a value indicated by the sensor data may vary due to thermal noise, but the data invalidation processing in the second aspect can more reliably remove the influence of noise from the sensor data and generate sensor data with high torque accuracy.

[0060] As described above, according to the embodiment of the present disclosure, the lead wire 11 is wired around the electrical cable 200, which is a source of noise occurrence, noise is detected based on an electrical signal generated in the lead wire 11, and a data portion affected by noise among the sensor data output from the sensor circuit 2 is invalidated. With such a configuration, an abnormal value affected by noise can be appropriately removed from the sensor data output from the (sensor circuit 2 of the) torque sensor 100, and thus, highly accurate sensor data about the torque can be generated.

[0061] Since the motor drive power subject to PWM control is generally switched quickly between high and low, the sensor data of a torque sensor located near an electric wire through which the motor drive power flows is more likely to be affected by noise. For example, a measure has conventionally been taken to reduce the influence of noise by averaging the sensor data, but there is a problem that high sensor processing speed is lost. In contrast, according to the present embodiment, a noise-affected data portion among the sensor data output from the sensor circuit 2 is invalidated, and thus high sensor processing speed can be ensured.

[0062] When noise is to be detected directly by monitoring sensor data output from a sensor circuit, the magnitude of the sensor data with noise is between a maximum value of the sensor data without noise and a minimum value of the sensor data without noise. Therefore, there is a possibility that the sensor data with noise and the normal sensor data without noise cannot be accurately distinguished. In contrast, in the present embodiment, only noise is detected by the noise detection circuit 12 based on an electrical signal generated in the lead wire 11 wired to surround the electrical cable 200, so that noise can be accurately detected.

[0063] The printed circuit board of the torque sensor 100 provided in the robot arm may have an opening for passing various cables. In the present embodiment, the lead wire 11 is wired to surround the opening of the printed circuit board 3 of the torque sensor 100, so that a noise suppression circuit can also be easily attached to a previous torque sensor. <Example of modification and alternative example of an embodiment>

[0064] In the embodiment described above, it is assumed that the noise detection signal indicates "Low" when the occurrence of noise is indicated, and that the noise detection signal indicates "High" when the absence of noise is indicated. As an alternative example, the noise detection signal may indicate "High" when the occurrence of noise is indicated, and the noise detection signal may indicate "Low" when the absence of noise is indicated.

[0065] In the embodiment described above, it is assumed that the electrical cable 200 is a power cable through which the drive power of the motor flows. As an alternative example, the power cable 200 may be a cable other than a power cable through which the drive power of the motor flows. For example, the power cable 200 may be a signal cable through which a PWM signal for controlling an inverter flows, or a power cable through which the supply voltage flows.

[0066] In the embodiment described above, it is assumed that the sensor circuit 2 is provided in the torque sensor 100, which detects the torque of the target object 300. As a modification example, the sensor circuit 2 may also be provided in a sensor other than a torque sensor. For example, the sensor circuit 2 may be a sensor circuit configured to output electrical sensor data from a current sensor, a voltage sensor, a magnetic sensor, a speed sensor, a temperature sensor, and the like.

[0067] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various kinds of additions, replacements, modifications, partial deletions, and the like can be made to the embodiments without affecting the purpose of the invention or the content described in the claims and the scope of the present invention derived from equivalents thereof. In the embodiments described above, for example, the order of operations and the order of processing pieces are given as an example, which is not limited thereto. The same applies to the case where a numerical value or a numerical expression is used in the description of the embodiments described above. LIST OF REFERENCE SYMBOLS 1 noise suppression circuit 2 Sensor circuit 3 Printed circuit board 11 Conductor wire 12 Noise detection circuit 13 Data processing circuit 21 Unit for adjusting DC components 21-1 Capacitor 21-2, 21-3 resistance 22 Threshold setting unit 23 Comparison unit 23-1 First Comparator 23-2 Second Comparator 24 Wired OR connection unit 25 filters 26 buffers 31 Opening 100 torque sensor 200 Electrical Cable 300 target object 1000 robots QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2010-71945A

[0004] WO 2017 / 014297A1

[0004]

Claims

[1] A noise reduction circuit configured to remove an influence of noise from data output by a sensor circuit, the noise reduction circuit comprising: a conducting wire wired to surround an electrical cable; a noise detection circuit configured to generate a noise detection signal indicating the presence or absence of noise in the electrical cable based on an electrical signal generated in the conducting wire; and a data processing circuit configured to invalidate data during an invalidation period comprising at least a period in which the noise detection signal indicates the occurrence of noise in the data output by the sensor circuit. [2] The noise reduction circuit according to claim 1, wherein the data processing circuit outputs data output from the sensor circuit during a period other than the invalid period as it is and stops outputting data output from the sensor circuit during the invalid period. [3] The noise reduction circuit according to claim 1, wherein the data processing circuit invalidates data during the invalid period among the data output from the sensor circuit, and then averages and outputs values ​​indicated by data output from the sensor circuit during a predetermined period including the invalid period. [4] The noise suppression circuit according to any one of claims 1 to 3, wherein a time point which is earlier by a predefined time period than a time period in which the noise detection signal indicates the occurrence of noise is set as a starting point of the invalid period. [5] The noise suppression circuit according to any one of claims 1 to 4, wherein the noise detection circuit comprises a DC component adjusting unit configured to adjust a DC component from an electrical signal generated in the conducting wire, and a noise detection signal generation unit configured to generate and output the noise detection signal indicating the occurrence of noise when it is determined by the DC component adjustment unit that an amplitude of the electrical signal having the adjusted DC component is outside a predefined threshold range. [6] A sensor comprising: a sensor circuit configured to output data that is a sensor detection result of a target object; the noise suppression circuit according to any one of claims 1 to 5, configured to remove an influence of noise from the data output by the sensor circuit; and a printed circuit board with an opening through which the electrical cable passes and on which the lead wire is wired to surround the opening. [7] The sensor according to claim 6, wherein the sensor circuit and the noise suppression circuit are provided on the printed circuit board.

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