Noise removal circuit and sensor

Abstract

This noise removal circuit that removes the effect of noise from the data output from a sensor circuit comprises: a conductor wire that surrounds an electric cable; a noise detection circuit for generating a noise detection signal indicating the presence or absence of noise in the electric cable on the basis of the electric signal generated in the conductor wire; and a data processing circuit that invalidates data output from the sensor circuit during an invalidation period that includes at least a period in which the noise detection signal indicates that noise has occurred.

Description

Noise removal circuit and sensor

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

[0002] The motor used to drive the robot arm is supplied with driving power by an inverter. The inverter is controlled based on a PWM (Pulse Width Modulation) signal. The wiring that supplies the PWM-controlled motor driving power can be a source of noise.

[0003] For example, there is known an AE measurement device that measures AE generated from a measured object, the AE measurement device including: a measurement AE sensor that detects AE signals generated from the measured object; an external noise AE sensor that detects external AE signals generated outside the measured object; a determination unit that determines whether or not external noise is present based on the external AE signal detected by the external noise AE sensor; and a measurement processing unit that validates an AE signal when the determination unit determines that no external noise is present when an AE signal is detected by the measurement AE sensor (see, for example, Patent Document 1).

[0004] For example, in a Rogowski current sensor in which multiple coils are connected continuously along a single closed line and a return line parallel to the closed line from the end of the last coil of the multiple coils to the start of the first coil, the voltage induced between the start terminal of the first coil and the terminal of the return line is detected as a function of the current in the circuit under test inserted inside the closed line. Each coil constituting the multiple coils is formed on a plane perpendicular to the closed line, and the end of one coil and the start of the next coil are connected by a forward line parallel to the closed line, and the entire forward line and the return line are arranged in close proximity to each other (see, for example, Patent Document 2).

[0005] JP 2010-71945 A International Publication No. 2017 / 014297

[0006] Noise caused by motor drive power adversely affects the accuracy of various sensors and the control of various devices. Therefore, it is extremely important to detect noise and eliminate its effects. For example, a robot arm is equipped with a torque sensor for detecting torque, and noise caused by motor drive power adversely affects the accuracy of the torque sensor. The problem to be solved by the present disclosure is to realize a noise elimination circuit that eliminates the effects of noise from data output from a sensor circuit, and a sensor equipped with the same.

[0007] According to one aspect of the present disclosure, a noise removal circuit that removes the effects of noise from data output from a sensor circuit includes a conductor wired to surround an electric cable, a noise detection circuit that generates a noise detection signal indicating whether or not noise is occurring in the electric cable based on an electric signal generated in the conductor, and a data processing circuit that invalidates data output from the sensor circuit during an invalidation period that includes at least a period during which the noise detection signal indicates the presence of noise occurrence.

[0008] Furthermore, according to one aspect of the present disclosure, the sensor includes a sensor circuit that outputs data that is the sensor detection result for an object, the noise removal circuit that removes the effects of noise from the data output from the sensor circuit, and a substrate having an opening through which an electric cable passes and on which conductors are wired to surround the opening.

[0009] 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 including the same.

[0010] FIG. 1 is a diagram illustrating a noise removal circuit and a torque sensor including the same according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating a robot including a torque sensor according to an embodiment of the present disclosure. FIG. 3 is a diagram illustrating noise generated due to motor drive power flowing through an electric cable. FIG. 4 is a perspective view illustrating a board according to a first mode of a torque sensor according to an embodiment of the present disclosure. FIG. 5 is a perspective view illustrating a board according to a second mode of a torque sensor according to an embodiment of the present disclosure. FIG. 6 is a perspective view illustrating a board according to a third mode of a torque sensor according to an embodiment of the present disclosure. FIG. 7 is a circuit diagram illustrating a configuration of a noise detection circuit in a noise removal circuit according to an embodiment of the present disclosure. FIG. 8 is a waveform diagram illustrating the function of the noise detection circuit in a noise removal circuit according to an embodiment of the present disclosure. FIG. 9 is a waveform diagram illustrating an example of a noise detection signal generated by the noise detection circuit in the noise removal circuit according to an embodiment of the present disclosure. FIG. 10 is a waveform diagram (part 1) illustrating filter setting by the noise detection circuit in the noise removal circuit according to an embodiment of the present disclosure. FIG. 11 is a waveform diagram (part 2) illustrating filter setting by the noise detection circuit in the noise removal circuit according to an embodiment of the present disclosure. FIG. 12 is a waveform diagram illustrating the relationship between noise and data during an invalidation period according to an embodiment of the present disclosure. FIG. 13 is a waveform diagram illustrating data invalidation processing according to a first mode of a data processing circuit in a noise removal circuit according to an embodiment of the present disclosure.

[0011] Hereinafter, a noise removal circuit and a torque sensor according to an embodiment will be described with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. Duplicate descriptions of those components may be omitted. In the following description, "connected" means "electrically connected."

[0012] <Overall Configuration of Noise Cancellation Circuit and Torque Sensor> Fig. 1 is a diagram showing a noise cancellation circuit and a torque sensor including the same according to an embodiment of the present disclosure, and Fig. 2 is a diagram showing a robot including the torque sensor according to an embodiment of the present disclosure.

[0013] According to an embodiment of the present disclosure, the torque sensor 100 includes a noise removal circuit 1, a sensor circuit 2, and a substrate 3 (not shown in FIG. 1 ). In this embodiment, as an example, the sensor circuit 2 is provided in the torque sensor 100 that detects the torque of the target object 300. As a variation of this, the sensor circuit 2 may be provided in a sensor other than a torque sensor. For example, the sensor circuit 2 may 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.

[0014] The torque sensor 100 is provided, for example, in the arm of a robot 1000. A substrate 3 of the torque sensor 100 is provided with a noise removal circuit 1, a sensor circuit 2, and the like.

[0015] The sensor circuit 2 outputs data (hereinafter referred to as "sensor data") that is the sensor detection result for the object 300. Here, a torque sensor is used as an example, so the sensor circuit 2 outputs sensor data related to the torque detected for the object 300. The object 300 that is the target of torque detection is a motor that drives the arm of a robot. The sensor data output by the sensor circuit 2 may be analog data (analog signal) or digital data (digital signal).

[0016] The noise removal circuit 1 removes the influence of noise from the sensor data output 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.

[0017] An opening is provided in the substrate 3 of the torque sensor 100. An electric cable 200, through which PWM-controlled motor drive power flows, is disposed so as to pass through the opening. The conductor 11 is routed so as to surround the opening on the substrate. Thus, the conductor 11 is routed so as to surround the electric cable 200, which is a noise source resulting from the motor drive power.

[0018] The noise detection circuit 12 generates a noise detection signal indicating whether or not noise is occurring in the electric cable 200, based on the electric signal occurring in the conductor 11. Details of the noise detection process performed by the noise detection circuit 12 will be described later.

[0019] The data processing circuit 13 invalidates sensor data during an invalidation period that includes at least a period during which the noise detection signal indicates the occurrence of noise, among the sensor data output from the sensor circuit 2. Details of the data invalidation process by the data processing circuit 13 will be described later.

[0020] An arithmetic processing unit (processor) is provided within the torque sensor 100. Examples of arithmetic processing units include an IC, an LSI, a CPU, an MPU, and a DSP. The data processing circuit 13 may be composed of only an arithmetic processing unit, or may be composed of a combination of an analog circuit and an arithmetic processing unit, or may be composed of only analog circuits. For example, if the data processing circuit 13 is constructed in the form of a software program, the functions of the data processing circuit 13 can be realized by operating the arithmetic processing unit in accordance with the software program. Alternatively, the data processing circuit 13 may be realized as a semiconductor integrated circuit on which a software program that realizes the functions of the data processing circuit 13 is written. Alternatively, the data processing circuit 13 may be realized as a recording medium on which a software program that realizes the functions of the data processing circuit 13 is written.

[0021] The conductor 11 and the noise detection circuit 12 may be replaced with a Rogowski coil type current detection circuit. In this case, the Rogowski coil type current detection circuit is connected to the data processing circuit 13, and the electric cable 200 is arranged to pass through an opening in the substrate on which the Rogowski coil is provided.

[0022] <Principle of Noise Generation Due to Motor Driving Power> FIG. 3 is a diagram illustrating an example of noise generated due to motor driving power flowing through an electric cable.

[0023] The wiring supplying PWM-controlled motor drive power is a noise source. The motor drive power flowing through the electric cable 200 is a square-wave voltage, and slight changes in the magnetic field occur around the electric cable 200 in response to changes in the high and low levels of the square-wave voltage, generating noise in the sensor data output from the sensor circuit 2 located near the electric cable 200. For example, as shown in Figure 3, 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, slight changes in the magnetic field occur around the electric cable 200 through which the motor drive power flows. As a result, noise occurs in the sensor data output from the sensor circuit 2 located near the electric cable 200 at times t2 and t4.

[0024] Therefore, in an embodiment of the present disclosure, in order to detect changes in the magnetic field around the electric cable 200 through which the motor drive power flows, the conductor 11 is wired to surround the electric cable 200. Noise is generated in the conductor 11 in response to changes in the motor drive power flowing through the electric cable 200. The noise detection circuit 12 generates a noise detection signal indicating the presence or absence of noise generation in the electric cable 200 based on an electric signal related to the noise generated in the conductor 11.

[0025] <Structure of the Board of the Noise Removal Circuit> The board of the torque sensor 100 provided on the arm of the robot 1000 may be provided with an opening for passing various cables. The electric cable 200 through which motor drive power flows is also disposed so as to pass through the opening of the board. Therefore, in an embodiment of the present disclosure, the conductor 11 is routed so as to surround the opening of the board 3 of the torque sensor 100, so that the conductor 11 surrounds the electric cable 200. Note that as a variation of this, an opening may be provided in the housing of the torque sensor 100, the conductor 11 is routed so as to surround the opening of the housing of the torque sensor 100, and the electric cable 200 is disposed so as to pass through this opening, so that the conductor 11 surrounds the electric cable 200.

[0026] Some examples of substrate configurations are listed below.

[0027] FIG. 4 is a perspective view showing a substrate according to a first embodiment of a torque sensor according to an embodiment of the present disclosure.

[0028] The substrate 3 according to the first embodiment has a circular ring shape with an opening 31 provided near the center of the disk-shaped substrate. An electric cable 200 passes through the opening 31. On the substrate 3, a conductor 11 wired so as to surround the opening 31, a noise detection circuit 12, and a data processing circuit 13 are provided.

[0029] FIG. 5 is a perspective view showing a substrate according to a second embodiment of a torque sensor according to an embodiment of the present disclosure.

[0030] The substrate 3 according to the second embodiment has a C-shaped shape with a notch cut out in a circumferential direction, and an opening 31 provided near the center of the substrate. An electric cable 200 passes through the opening 31. On the substrate 3, a conductor 11 wired in a C shape so as to surround part of the opening 31, a noise detection circuit 12, and a data processing circuit 13 are provided.

[0031] FIG. 6 is a perspective view showing a substrate according to a third embodiment of a torque sensor according to an embodiment of the present disclosure.

[0032] The substrate 3 according to the third embodiment has a shape in which an opening 31 is provided near the center of the substantially rectangular substrate. An electric cable 200 passes through the opening 31. On the substrate 3, a conductor 11 wired in a substantially rectangular shape so as to surround the opening 31, a noise detection circuit 12, and a data processing circuit 13 are provided.

[0033] The first to third forms described above are merely examples, and the substrate may have a substrate shape and wiring shape other than those shown in the figures, as long as the substrate is wired so that the conductor 11 surrounds the opening 31 through which the electric cable 200 passes.

[0034] <Example of Configuration of Noise Detection Circuit> FIG. 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.

[0035] As described above, the noise detection circuit 12 is connected to the conductor 11 and the data processing circuit 13. The terminals P1 and P2 of the sensor circuit 2 are connected to strain gauges whose resistance value changes depending on the torque applied to the motor.

[0036] 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 .

[0037] The DC component adjustment unit 21 has a capacitor 21-1 that removes DC components from the electrical signal generated in the conductor 11, and resistors 21-2 and 21-3 that apply a specified DC component. In the DC component adjustment unit 21, the capacitor 21-1 removes DC components from the electrical signal generated in the conductor 11, and the resistors 21-2 and 21-3 reapply a specified DC component. The resistors 21-2 and 21-3 adjust the reference voltage when there is no noise to fall between an upper threshold and a lower threshold set by the threshold setting unit 22 (hereinafter, sometimes referred to as the "threshold range").

[0038] 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.

[0039] 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 an oscillatory signal having a positive amplitude and a negative amplitude. To detect this noise, the threshold setting unit 22 sets an upper threshold used for comparison with the positive amplitude of the electrical signal and a lower threshold used for comparison with the negative amplitude of the electrical signal. The upper threshold is input to the inverting input (−) of a first comparator 23-1 that constitutes the comparing unit 23. The lower threshold is input to the non-inverting input (+) of a second comparator 23-2 that constitutes the comparing unit 23.

[0040] The comparison unit 23 compares a threshold value consisting of an upper threshold value and a lower threshold value with the electrical signal whose DC component has been adjusted by the DC component adjustment unit 21. For this purpose, the comparison unit 23 has a first comparator 23-1 and a second comparator 23-2.

[0041] The electrical signal whose DC component has been adjusted by the DC component adjuster 21 is input to the non-inverting input (+) of the first comparator 23-1, and an upper threshold is input to the inverting input (-). The first comparator 23-1 can detect whether the positive amplitude of the electrical signal whose DC component has been adjusted by the DC component adjuster 21 exceeds the upper threshold. The electrical signal whose DC component has been adjusted by the DC component adjuster 21 is input to the inverting input (-) of the second comparator 23-2, and a lower threshold is input to the non-inverting input (+). The second comparator 23-2 can detect whether the negative amplitude of the electrical signal whose DC component has been adjusted by the DC component adjuster 21 falls below the lower threshold.

[0042] The signals output from the comparison unit 23 (first comparator 23-1 and second comparator 23-2) are input to the wired OR connection unit 24. The wired OR connection unit 24 is provided to take the logical sum (OR) of the signal output when the first comparator 23-1 determines that the positive amplitude of the electrical signal has exceeded the upper threshold, and the signal output when the second comparator 23-2 determines that the negative amplitude of the electrical signal has fallen below the lower threshold. The presence of the wired OR connection unit 24 makes it possible to detect the occurrence of noise regardless of whether the first comparator 23-1 determines that the positive amplitude of the electrical signal has exceeded the upper threshold or the second comparator 23-2 determines that the negative amplitude of the electrical signal has fallen below the lower threshold occurs first.

[0043] The comparison unit 23 and the wired OR connection unit 24 are configured by, for example, a reset IC.

[0044] The filter 25 and the buffer 26 have the function of suppressing fluctuations in the presence or absence of noise that may occur as a result of generating a noise detection signal based on a comparison with a threshold value, thereby improving noise detection accuracy.

[0045] For example, by having the above-described configuration, the noise detection circuit 12 generates and outputs a noise detection signal indicating the presence of noise when it determines that the electrical signal generated in the conductor 11 is greater than the upper threshold or less than the lower threshold, i.e., when the electrical signal generated in the conductor 11 falls outside a threshold range between the upper and lower thresholds. Furthermore, the noise detection circuit 12 generates and outputs a noise detection signal indicating the absence of noise when it determines that the electrical signal generated in the conductor 11 is smaller than the upper threshold and greater than the lower threshold, i.e., when the electrical signal generated in the conductor 11 falls within a threshold range between the upper and lower thresholds. The noise detection signal, for example, indicates low when noise is present and high when noise is absent. The noise detection signal generated by the noise detection circuit 12 as described above is input to the data processing circuit 13.

[0046] <Function of Noise Detection Circuit> Figure 8 is a waveform diagram illustrating the function of the noise detection circuit in the noise removal circuit according to the embodiment of the present disclosure. In Figure 8, black dots indicate sampling points by the data processing circuit 13 for the sensor data output from the sensor circuit 2 of the torque sensor 100. That is, the data processing circuit 13 samples the sensor data at times t5, t6, t7, t8, t9, t 10 , and time t 11 Then, the sensor data output from the sensor circuit 2 is sampled.

[0047] When the torque sensor 100 is located near the electric cable 200 through which the motor drive power flows, noise occurs in the sensor data output from the sensor circuit 2 of the torque sensor 100. In the example shown in Fig. 8, noise occurs at time t7 and time t9, for example. If an attempt is made to directly detect noise by monitoring the sensor data output from the sensor circuit 2, the magnitude of the sensor data containing noise at time t7 and time t9 will be larger than the sensor data (maximum value) at time t6 which does not contain noise. 10Therefore, it may be impossible to accurately distinguish between sensor data containing noise and normal sensor data that does not contain noise. In contrast, in the embodiment of the present disclosure, the noise detection circuit 12 detects only noise based on the electrical signal generated in the conductor 11 that is wired to surround the electric cable 200 (the waveform diagram at the bottom of FIG. 8 ), so that noise can be accurately detected.

[0048] <Relationship between noise detection signal and invalidation processing period>

[0049] 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.

[0050] When the electrical signal generated in the conductor 11 (in FIG. 7, the electrical signal whose DC component has been adjusted by the DC component adjuster 21) falls outside the threshold range, the noise detection circuit 12 generates a noise detection signal indicating that noise has occurred. 12 At time t 12 A predetermined period of time has elapsed since time t 13 During this time, the torque sensor 100 outputs a noise detection signal (Low) indicating the presence of noise, and during other times, it outputs a noise detection signal (High) indicating the absence of noise. Because the arrangement of the inverter circuit and the electric cable 200 that electrically affect the torque sensor 100 provided in the robot 1000 does not change significantly since the robot was manufactured, the noise contained in the electric signal generated in the conductor 11 is reproducible. Therefore, the time required for the noise to subside after it occurs is also approximately constant. Therefore, in an embodiment of the present disclosure, the time required for the noise to subside after it occurs is measured in advance, for example, during development of the robot 1000, and the time required for the noise to subside after it occurs is set based on the measured time. The constants of the filter 25 are determined based on this set time.

[0051] 10 and 11 are waveform diagrams illustrating filter settings by the noise detection circuit in the noise removal circuit according to an embodiment of the present disclosure.

[0052] 10, when the constant of the filter 25 is set to a weak value, the magnitude relationship between the upper threshold and the lower threshold of the electrical signal input to the noise detection circuit 12 (i.e., the electrical signal generated in the conductor 11) is reversed within a short period of time. This results in "fluttering of the noise detection signal," in which the noise detection signal switches between a low level indicating the presence of noise and a high level indicating the absence of noise within a short period of time.

[0053] As shown in FIG. 11 , when the constant of the filter 25 is set to a relatively strong value, the electrical signal input to the noise detection circuit 12 (i.e., the electrical signal generated in the conductor 11) exceeds the upper threshold value, and a noise detection signal (Low) indicating the occurrence of noise is output at time t 12 From the time t 15 This results in unnecessary invalidation of data in areas without noise.

[0054] Therefore, in an embodiment of the present disclosure, when developing the robot 1000, the time required for noise to subside after it occurs is measured in advance, and based on the measured time, the time required for noise to subside after it occurs is set, and an appropriate constant for the filter 25 is determined based on this set time.

[0055] FIG. 12 is a waveform diagram illustrating the relationship between noise and data during the invalidation period in the embodiment of the present disclosure.

[0056] As described with reference to FIG. 9, the time t 12 is the start point of the noise detection signal (Low) indicating the occurrence of noise. However, the actual start point of the noise detection signal is the time t 1212 , noise that does not exceed the threshold value has been occurring since a time point before t , which is the start point of the noise detection signal (Low) indicating the occurrence of noise. As described above, noise contained in the electrical signal generated in the conductor 11 is reproducible. Therefore, in an embodiment of the present disclosure, the time required for the electrical signal to exceed the threshold value after noise generation is measured in advance, for example, during development of the robot 1000, and based on the measured time, a time point a predetermined time before the start point of the noise detection signal (Low) indicating the occurrence of noise is set as the start point of the invalidation period of the sensor data. In the example shown in FIG. 12 , the start point of the noise detection signal (Low) indicating the occurrence of noise is set as the start point of the invalidation period of the sensor data. 12 earlier than 14 is set as the start point of the invalidation period of the sensor data. Note that the time t 12 time t before 14 Therefore, the sensor data output 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.

[0057] In order to simplify the configuration and processing within the noise removal circuit 1, the time t 12 may be set as the start point of the invalidation period of the sensor data. In this case, it is possible to omit the storage unit because it is not necessary to temporarily store the sensor data.

[0058] <Data invalidation processing by data processing circuit> The data processing circuit 13 invalidates sensor data output from the sensor circuit 2 during an invalidation period that includes at least a period during which the noise detection signal indicates the occurrence of noise. Below, several data invalidation processing operations performed by the data processing circuit are listed.

[0059] 13 is a waveform diagram showing data invalidation processing by a first mode of the data processing circuit in the noise removal circuit according to an embodiment of the present disclosure. In the example shown in FIG. 13, as an example, the start point of the noise detection signal (Low) indicating the occurrence of noise is set as the start point of the invalidation period of the sensor data. Note that the start point of the invalidation period of the sensor data in the data processing circuit 13 may be set to a point a predetermined time before the start point of the noise detection signal (Low) indicating the occurrence of noise.

[0060] In the data invalidation process according to the first embodiment, the data processing circuit 13 outputs the data output from the sensor circuit 2 as is during periods other than the invalidation period, and stops outputting the data output from the sensor circuit 2 during the invalidation period. 17 From time t 18 Since the noise detection signal (Low) indicating the occurrence of noise is output from the noise detection circuit 12 until time t 17 From time t 18 During the invalidation period up to the end of the period, the output of data from the sensor circuit 2 is stopped, and during periods other than the invalidation period, the data output from the sensor circuit 2 is output as is. According to the data invalidation process of the first form, the influence of noise can be removed from the sensor data.

[0061] 14 is a waveform diagram showing a data invalidation process according to a second mode of the data processing circuit in the noise removal circuit according to the embodiment of the present disclosure. In FIG. 14, the sampling points S1 to S2 by the data processing circuit 13 for the sensor data output from the sensor circuit 2 are set as S1 to S2. 12 14, as an example, the start point of the noise detection signal (Low) indicating the occurrence of noise is set as the start point of the invalidation period of the sensor data. Note that the data processing circuit 13 may set the start point of the invalidation period of the sensor data to a point a predetermined time before the start point of the noise detection signal (Low) indicating the occurrence of noise.

[0062] In the data invalidation process according to the second embodiment, the data processing circuit 13 invalidates the sensor data output from the sensor circuit 2 during the invalidation period, 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. 19 From time t 20 Until time t 21 From time t 22 Between t 23 From time t 23 Sampling points S3, S7, S 11 The sensor data at the sampling points S1, S2, S4, S5, S6, S8, S9, and S10 during the period other than the invalidation period is invalidated. 10 and S 12 The values ​​indicated by the sensor data in the above example are averaged and output. The time period for averaging can be set arbitrarily. For example, if the sensor data output from the sensor circuit 2 is an analog signal, variations in the values ​​indicated by the sensor data may occur due to thermal noise or the like. However, the data invalidation process according to the second embodiment more reliably removes the effects of noise from the sensor data, making it possible to generate highly accurate sensor data related to torque.

[0063] As described above, according to the embodiment of the present disclosure, the conductor 11 is wired around the electric cable 200, which is a noise generation source, and noise is detected based on the electrical signal generated in the conductor 11, and data portions affected by the noise are invalidated from the sensor data output from the sensor circuit 2. With this configuration, abnormal values ​​affected by noise can be accurately removed from the sensor data output from the torque sensor 100 (sensor circuit 2 thereof), making it possible to generate highly accurate sensor data related to torque.

[0064] Generally, PWM-controlled motor drive power switches between high and low states at high speeds, making sensor data from torque sensors located around the electric cables through which the motor drive power flows susceptible to noise. Conventional approaches to reducing the effects of noise include averaging the sensor data over time, but this approach results in a loss of high-speed sensor processing. In contrast, according to an embodiment of the present disclosure, the sensor data output from the sensor circuit 2 is invalidated if affected by noise, thereby ensuring high-speed sensor processing.

[0065] Furthermore, if an attempt were made to directly detect noise by monitoring the sensor data output from the sensor circuit as is, the magnitude of the noisy sensor data would fall between the maximum value and the minimum value of the noise-free sensor data. This could make it difficult to accurately distinguish between noisy sensor data and normal sensor data that does not contain noise. In contrast, in the embodiment of the present disclosure, the noise detection circuit 12 detects only noise based on the electrical signal generated in the conductor 11 that is wired to surround the electric cable 200, thereby enabling accurate noise detection.

[0066] Furthermore, the circuit board of the torque sensor 100 provided on the arm of a robot may have an opening for passing various cables through. In the embodiment of the present disclosure, the conductors 11 are wired so as to surround the opening in the circuit board 3 of the torque sensor 100, so that a noise removal circuit can be easily implemented in conventional torque sensors.

[0067] <Modifications and alternatives of the embodiment>

[0068] In the embodiment described above, the noise detection signal indicates Low when noise is occurring and High when noise is not occurring. As an alternative example, the noise detection signal may indicate High when noise is occurring and Low when noise is not occurring.

[0069] In the embodiment described above, the electric cable 200 is a power cable through which motor drive power flows. As a variation of this, the electric cable 200 may be a cable other than a power cable through which motor drive power flows. For example, the electric cable 200 may be a signal cable through which a PWM signal used to control an inverter flows or a power cable through which power from a power source flows.

[0070] In the embodiment described above, the sensor circuit 2 is provided in the torque sensor 100 that detects the torque of the object 300. As a modification, the sensor circuit 2 may be provided in a sensor other than a torque sensor. For example, the sensor circuit 2 may 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.

[0071] Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the invention or the spirit of the present invention derived from the content of the claims and their equivalents. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0072] REFERENCE SIGNS LIST 1 noise removal circuit 2 sensor circuit 3 substrate 11 conducting wire 12 noise detection circuit 13 data processing circuit 21 DC component adjustment section 21-1 capacitor 21-2, 21-3 resistor 22 threshold setting section 23 comparison section 23-1 first comparator 23-2 second comparator 24 wired OR connection section 25 filter 26 buffer 31 opening 100 torque sensor 200 electric cable 300 object 1000 robot

Claims

1. A noise removal circuit that removes the effect of noise from data output from a sensor circuit, A conductor wired so as to surround the electric cable; a noise detection circuit that generates a noise detection signal indicating the presence or absence of noise in the electric cable based on the electric signal generated in the conductor; a data processing circuit for invalidating data output from the sensor circuit during an invalidation period including at least a period during which the noise detection signal indicates the occurrence of noise; A noise elimination circuit comprising:

2. 2. The noise removal circuit according to claim 1, wherein the data processing circuit outputs the data output from the sensor circuit as is during a period other than the disabled period, and stops outputting the data output from the sensor circuit during the disabled period.

3. 2. The noise removal circuit according to claim 1, wherein the data processing circuit invalidates data output from the sensor circuit during the invalidation period, and averages and outputs values ​​indicated by the data output from the sensor circuit during a predetermined period including the invalidation period.

4. 4. The noise removal circuit according to claim 1, wherein a point in time a predetermined time before a period in which the noise detection signal indicates the occurrence of noise is set as a starting point of the invalidation period.

5. The noise detection circuit includes: a DC component adjusting unit for adjusting a DC component from the electrical signal generated in the conductor; a noise detection signal generating unit that generates and outputs the noise detection signal indicating the occurrence of noise when it is determined that the amplitude of the electrical signal, the DC component of which has been adjusted by the DC component adjusting unit, falls outside a predetermined threshold range; The noise removal circuit according to any one of claims 1 to 3, comprising:

6. A sensor circuit that outputs data representing a sensor detection result regarding an object; A noise removal circuit according to any one of claims 1 to 3, which removes the effect of noise from data output from the sensor circuit; a substrate having an opening through which the electric cable passes and on which the conductor wire is wired so as to surround the opening; A sensor comprising:

7. The sensor of claim 6 , wherein the sensor circuit and the noise removal circuit are provided on the substrate.