JP7405602B2 - Noise removal device - Google Patents

Description

The present invention relates to a noise removal device.

Improving speed and trajectory accuracy by reducing vibration during robot operation directly leads to improvements in production efficiency and quality. Therefore, there is a desire to reduce vibrations and trajectory deviations that occur when robots operate. In particular, it is desired that the robot operate without vibration during spot welding using a welding gun.
In this regard, a method has been proposed in which an acceleration sensor is attached to a location where vibrations are to be removed or where a high-precision trajectory is to be achieved, the acceleration sensor measures vibrations during robot movement, and the vibrations are reduced by performing learning control. . For example, see Patent Documents 1 and 2.
When measuring robot vibration using an acceleration sensor, the sensor data contains noise. This noise may make it impossible to accurately measure the robot's vibrations and make it impossible to make correct corrections to remove the robot's vibrations. Therefore, a low-pass filter, a median filter, or the like is generally used to remove noise from sensor data.

Japanese Patent Application Publication No. 2011-167817 JP 2018-118353 Publication

For example, an acceleration sensor may be installed on a welding gun to remove vibrations from a robot to which the welding gun is attached. When the welding gun is operated while the acceleration sensor is measuring, the acceleration sensor instantaneously detects a signal with a large value due to the impact of the operation of the welding gun. This signal is noise that causes errors in estimating the robot's motion trajectory.
Furthermore, if a low-pass filter is applied to remove instantaneously generated noise, signals in noise-free areas will also be affected. Furthermore, low-pass filters cannot completely remove noise.

Therefore, even when the welding gun is operated to measure the acceleration sensor, it is desired to remove the noise generated due to the influence of the welding gun.

One aspect of the noise removal device of the present disclosure is a noise removal device that removes noise from acceleration data of an acceleration sensor installed in a welding gun attached to a robot, wherein the noise removal device removes noise from acceleration data of an acceleration sensor installed in a welding gun attached to a robot, the The sensor includes a data replacement unit that replaces sensor acceleration data with pseudo acceleration data and outputs the pseudo acceleration data.

According to one aspect, even when the welding gun is operated and the acceleration sensor is measured, noise generated due to the influence of the welding gun can be removed.

1 is a functional block diagram showing an example of a functional configuration of a robot system according to a first embodiment. FIG. It is a figure which shows an example of the acquired acceleration data. 3 is a diagram illustrating an example in which acceleration data in a motion section is deleted from the acceleration data in FIG. 2. FIG. It is a figure which shows an example of the result of the Fourier analysis with respect to the extracted acceleration data. FIG. 7 is a diagram showing an example of acceleration data in which motion sections are replaced with pseudo acceleration data. It is a flowchart explaining replacement processing of a noise removal device. FIG. 3 is a functional block diagram showing an example of the functional configuration of a robot system according to a second embodiment. FIG. 7 is a diagram illustrating an example of acceleration data from which acceleration data in a motion section has been deleted. FIG. 7 is a diagram showing an example of acceleration data in which motion sections are replaced with pseudo acceleration data. 10 is a diagram showing an example of acceleration data to which an averaging filter is applied to the acceleration data of FIG. 9. FIG. FIG. 7 is a diagram illustrating an example of embedding acceleration data at timings where the values of the acceleration data at the joint between a motion section and an adjacent section are close to each other. It is a flowchart explaining replacement processing of a noise removal device.

The first embodiment will be described below with reference to the drawings.
<First embodiment>
FIG. 1 is a functional block diagram showing an example of the functional configuration of the robot system according to the first embodiment. As shown in FIG. 1, the robot system includes a robot 10, a robot control device 20, and a noise removal device 30.

The robot 10, the robot control device 20, and the noise removal device 30 may be directly connected to each other via a connection interface (not shown). Note that the robot 10, the robot control device 20, and the noise removal device 30 may be connected to each other via a network such as a LAN (Local Area Network). In this case, the robot 10, the robot control device 20, and the noise removal device 30 may be provided with a communication unit (not shown) for communicating with each other through such a connection.
Note that the noise removal device 30 may be included in the robot control device 20, as described later.

<Robot 10>
The robot 10 is, for example, an industrial robot. The robot 10, for example, as shown in FIG. It has arm portions 12 connected to each other. The robot 10 drives the arm portion 12 by driving each of the servo motors (not shown) arranged at each of the joint axes 11(1) to 11(6) based on a drive command from the robot control device 20. drive movable members such as Further, an end effector such as a welding gun, a gripping hand, a laser irradiation device, etc. is attached to the tip of the movable member of the robot 10, for example, the tip of the joint shaft 11 (6). A welding gun 13 is attached to the robot 10 in FIG. 1 as an end effector. Further, an acceleration sensor 100 is installed in the welding gun 13.
Although the robot 10 is a six-axis vertically articulated robot, it may be a vertically articulated robot other than six axes, a horizontally articulated robot, a parallel link robot, or the like.

The acceleration sensor 100 periodically detects the acceleration at the tip of the movable member as the robot 10 moves at a predetermined sampling time. The acceleration sensor 100 has a clock unit (not shown), and each time it detects acceleration, it acquires time information output from the clock unit as the detected time. Further, the acceleration sensor 100 transmits a sensor signal including, for example, the detected acceleration and time information to the robot control device 20 and the noise removal device 30.
Note that the predetermined sampling time may be set as appropriate depending on the operation content of the robot 10, the environment of the factory where the robot 10 is placed, and the like.
Further, the operation timing of the robot 10 and the welding gun 13 and the data acquisition timing of the acceleration sensor 100 may be synchronized within the robot control device 20, which will be described later.

<Robot control device 20>
The robot control device 20 is a control device (also referred to as a "robot controller") that outputs a motion command signal to the robot 10 and controls the motion of the robot 10 based on a program.
Specifically, the robot control device 20 reduces vibrations in the welding gun 13 at the tip of the robot 10 based on acceleration data (sensor data) from the acceleration sensor 100 from which noise has been removed by a noise removal device 30, which will be described later. A motion command signal is output to the robot 10 to control the motion of the robot 10 so as to reduce the amount of energy. Note that a method for outputting an operation command signal to the robot 10 based on the acceleration data to reduce vibrations in the welding gun 13 at the tip of the robot 10 is based on known methods such as those disclosed in Patent Documents 1 and 2. can be used, and detailed explanation will be omitted.

Note that the robot control device 20 has an operation sequence of a welding operation performed by the robot 10 using the welding gun 13 in advance. For example, in the case of spot welding, the robot controller 20 causes the robot 10 to move the welding gun 13 to the welding location (nugget creation position), and then causes the tip of the welding gun 13 to approach the workpiece to be welded. "approach", "gun close" in which the tip of the welding gun 13 contacts the workpiece, "pressure" to weld, and "gun open" in which the welding gun 13 releases the workpiece. . In other words, when the robot control device 20 outputs the operation sequence "spot command" to the robot 10, the noise removal device 30, which will be described later, can detect the timing at which the welding gun 13 operates.
Here, the "gun close" of the operation sequence "spot command" is the moment when the tip of the welding gun 13 comes into contact with the workpiece, so it is also called "hitting the welding gun 13." In addition, "pressure" in the operation sequence "spot command" includes "squeeze", the time from when the electrode is pressurized until the start of energization, "weld", the time during which welding current is applied, and "pressure" for the nugget solidification. Includes "hold" time. Further, the "gun open" of the operation sequence "spot command" includes the time "off" from pressurization release to transition to the next welding.

<Noise removal device 30>
The noise removal device 30 is a computer device or the like, and receives a sensor signal including acceleration detected by an acceleration sensor 100 installed on a welding gun 13 attached to the robot 10 and time information. The noise removal device 30 removes noise from the acceleration data of the acceleration sensor 100 included in the received sensor signal. Then, the noise removal device 30 outputs the noise-removed acceleration data to the robot control device 20.
As shown in FIG. 1, the noise removal device 30 according to this embodiment includes a control section 300 and a storage section 310. Furthermore, the control section 300 is configured to include a data replacement section 301.

Note that the noise removal device 30 includes an arithmetic processing device (not shown) such as a CPU (Central Processing Unit) in order to realize the operations of the functional blocks shown in FIG. In addition, the noise removal device 30 is used to store various control programs in an auxiliary storage device (not shown) such as a ROM (Read Only Memory) or an HDD (Hard Disk Drive), or a temporary storage device when the arithmetic processing unit executes the programs. A main storage device (not shown) such as a RAM (Random Access Memory) is provided for storing data required for the computer.

Then, in the noise removal device 30, the arithmetic processing unit reads the OS and application software from the auxiliary storage device, expands the read OS and application software to the main storage device, and performs arithmetic processing based on these OS and application software. Let's do it. Based on this calculation result, the noise removal device 30 controls each piece of hardware. Thereby, the processing by the functional blocks of FIG. 1 is realized. In other words, the noise removal device 30 can be realized by hardware and software working together.

The data replacement unit 301 acquires the acceleration detected by the acceleration sensor 100 and time information from the sensor signal received from the robot 10. Of the acquired acceleration data, the data replacement unit 301 replaces the acceleration data of the acceleration sensor 100 in the operation section in which the welding gun 13 operated with pseudo acceleration data, which will be described later, and outputs the data to the robot control device 20.
FIG. 2 is a diagram showing an example of acquired acceleration data. Note that the horizontal axis in FIG. 2 indicates time, and the vertical axis in FIG. 2 indicates acceleration. Further, in FIG. 2, for example, a period in which the welding gun 13 operates according to the operation sequence of the "spot command", that is, an operation section that is the timing of the welding gun 13 to strike, is indicated by a broken rectangle.
In addition, in the operation section indicated by the broken line, a series of spot welding operations of "approach", "gun opening", "pressurization", and "gun opening" described above are performed. For example, the noise removal device 30 (control unit 300) may specify the motion section based on a motion command signal output from the robot control device 20 to the robot 10.

For example, the data replacement unit 301 temporarily deletes the acceleration data in the motion section indicated by the broken line, which is affected by the impact caused by the motion of the welding gun 13, as shown in FIG. Then, the data replacement unit 301 extracts acceleration data for a section where the welding gun 13 is not operating and the robot 10 is in the same posture (movement) as when the welding gun 13 is operating. .
Specifically, since the robot 10 is stationary during spot welding, the data replacement unit 301 records the state in which the gun axis after being hit by the tip of the welding gun 13 is stopped and the robot 10 is in the same posture. Extract acceleration data in a stationary section, that is, acceleration data before and after a motion section. For example, in the case of the acceleration data shown in FIG. 3, the welding gun 13 is not operating in the section immediately after the operation section, and the robot 10 is in the same posture (movement) as when the welding gun 13 is operating. From this, the data replacement unit 301 extracts the acceleration data of the section immediately after the motion section. The data replacement unit 301 performs Fourier analysis such as FFT (Fast Fourier Transform) on the extracted acceleration data. Then, the data replacement unit 301 stores the frequency spectrum data obtained through the Fourier analysis in the storage unit 310, which will be described later.
FIG. 4 is a diagram showing an example of the results of Fourier analysis on the extracted acceleration data.
The data replacement unit 301 generates a composite waveform of sine waves as pseudo acceleration data based on the result of the Fourier analysis shown in FIG. 4 stored in the storage unit 310. The data replacement unit 301 replaces the generated pseudo acceleration data as acceleration data of the motion section.

FIG. 5 is a diagram showing an example of acceleration data in which motion sections are replaced with pseudo acceleration data.
Then, the data replacement unit 301 outputs the acceleration data replaced with the pseudo acceleration data as the acceleration data of the motion section to the robot control device 20 as output data. By doing so, the noise removal device 30 can remove noise generated due to the influence of the welding gun 13 even when the welding gun 13 is operated and the acceleration sensor 100 is measured.

Note that when generating the pseudo acceleration data, the data replacement unit 301 replaces the values at both ends of the acceleration data before deletion in the motion section with the pseudo acceleration data so that the acceleration data of the motion section and the section adjacent to the motion section are smoothly connected. The phase of the sine wave to be synthesized may be adjusted so that the difference between the values at both ends of the acceleration data is equal to or less than a predetermined threshold. Here, the predetermined threshold value may be determined as appropriate depending on the required accuracy of noise removal.

Furthermore, if the motion (posture) of the robot 10 during the next operation of the welding gun 13 is similar to the motion (posture) of the robot 10 in the motion section of FIG. Frequency spectrum data may also be used. By doing so, data replacement unit 301 does not need to extract acceleration data and perform Fourier analysis every time welding gun 13 operates, and can shorten processing time. However, in this case, it is preferable that the data replacement unit 301 also stores data on the motion (posture) of the robot 10 in the motion section along with the frequency spectrum data.

The storage unit 310 is a RAM or the like, and stores frequency spectrum data etc. obtained by Fourier analysis by the data replacement unit 301.

<Replacement process of noise removal device 30>
Next, the operation related to the replacement process of the noise removal device 30 according to the present embodiment will be described.
FIG. 6 is a flowchart illustrating the replacement process of the noise removal device 30. The flow shown here is repeatedly executed every time the noise removal device 30 detects the operation of the welding gun 13 based on the operation command signal output from the robot control device 20 to the robot 10.

In step S11, the data replacement unit 301 acquires acceleration data detected by the acceleration sensor 100 from the sensor signal received from the robot 10.

In step S12, the data replacement unit 301 deletes the acceleration data of the operation section in which the welding gun 13 operated from among the acceleration data acquired in step S11.

In step S13, the data replacement unit 301 extracts acceleration data for a section in which the welding gun 13 is not operating and in which the robot 10 is in the same posture as when the welding gun 13 is operating.

In step S14, the data replacement unit 301 performs Fourier analysis on the acceleration data extracted in step S13.

In step S15, the data replacement unit 301 generates a synthesized waveform obtained by synthesizing the sine waves as pseudo acceleration data based on the result of the Fourier analysis in step S14.

In step S16, the data replacement unit 301 replaces the pseudo acceleration data generated in step S15 as acceleration data of the motion section. Then, the data replacement unit 301 outputs the acceleration data replaced with the pseudo acceleration data in the motion section to the robot control device 20.

As described above, the noise removal device 30 according to the first embodiment is configured to use acceleration data in the operation section in which the welding gun 13 operates, among the acceleration data acquired from the acceleration sensor 100 installed on the welding gun 13 attached to the robot 10. Delete. The noise removal device 30 extracts acceleration data of a section where the welding gun 13 is not operating and where the robot 10 is in the same posture as when the welding gun 13 is operating, and extracts the extracted acceleration data. Perform Fourier analysis on the data. Based on the result of the Fourier analysis, the noise removal device 30 generates a composite waveform of sine waves as pseudo acceleration data, and replaces the generated pseudo acceleration data as acceleration data of the motion section.
Thereby, the noise removal device 30 can remove the noise generated due to the influence of the welding gun 13 even when the welding gun 13 is operated and the acceleration sensor 100 is measured.
The first embodiment has been described above.

<Second embodiment>
The noise removal device 30A according to the second embodiment uses acceleration data of an acceleration sensor in a section where the welding gun is not operating and where the robot is in the same posture as when the welding gun is operating. This embodiment differs from the first embodiment in that the series data is pseudo acceleration data of the motion section.
A second embodiment will be described below.

FIG. 7 is a functional block diagram showing an example of the functional configuration of the robot system according to the second embodiment. Note that elements having the same functions as the elements of the robot system in FIG. 1 are given the same reference numerals, and detailed explanations are omitted.
The noise removal device 30A according to the second embodiment is configured to include a control section 300a and a storage section 310a, similarly to the noise removal device 30 according to the first embodiment. Further, the control section 300a is configured to include a data replacement section 301a.

As shown in FIG. 8, like the data replacing unit 301 according to the first embodiment, the data replacing unit 301a temporarily replaces the acceleration data in the operation section indicated by the broken line, which is affected by the impact caused by the operation of the welding gun 13. delete. Similarly to the data replacing unit 301 according to the first embodiment, the data replacing unit 301a is configured in a section in which the welding gun 13 is not operating, and in which the robot 10 is in the same posture as when the welding gun 13 is operating. (movement), that is, the time series data of acceleration data of the section before and after the motion period is extracted. The data replacement unit 301a stores time-series data of the extracted acceleration data in a storage unit 310a, which will be described later. Then, for example, as shown in FIG. 9, the data replacement unit 301a embeds and replaces the time series data of the acceleration data stored in the storage unit 310a in the motion section as pseudo acceleration data.

Here, as shown in Figure 9, when replacing the pseudo acceleration data with a waveform at an arbitrary timing, the waveform of the acceleration data loses continuity near the boundary of the operation section and becomes high frequency data. . In order to avoid this discontinuity in the waveform of the acceleration data, the data replacement unit 301a may apply an averaging filter (smoothing filter) or the like around the joint of the acceleration data, that is, around the boundary of the motion section. By doing so, as shown in FIG. 10, it is possible to smoothly connect the acceleration data between the motion section and the adjacent section.
Furthermore, by applying the averaging filter to the area around the boundary of the motion section, the influence of the averaging filter on acceleration data in noise-free areas can be minimized.
Note that in FIG. 10, the averaging filter is applied to the acceleration data around the left-most boundary of the motion section, but the averaging filter may also be applied to the acceleration data around the right-most boundary of the motion section. .

The data replacement unit 301a then outputs the acceleration data replaced with the pseudo acceleration data in the motion section to the robot control device 20.
Note that, if the posture (motion) of the robot 10 during the next operation of the welding gun 13 is the same as the posture (motion) of the robot 10 in the motion section of FIG. Time series data of acceleration data may also be used. By doing so, the data replacement unit 301a does not need to extract time-series data of acceleration data every time the welding gun 13 operates, and can shorten processing time. However, in this case, it is preferable that the data replacement unit 301a also stores data on the posture (motion) of the robot 10 in the motion section, along with the time series data of the acceleration data.

Note that the data replacement unit 301a embeds the extracted time series data of the acceleration data as pseudo acceleration data in the motion section and applies an averaging filter near the joint of the acceleration data, but the present invention is not limited thereto. For example, as shown in FIG. 11, the data replacement unit 301a may embed data at a timing when the values of the acceleration data at the joint between the motion section and the section adjacent to the motion section are close.

The storage unit 310a stores acceleration data extracted by the data replacement unit 301a in an area where the welding gun 13 is not operating and the robot is in the same posture as when the welding gun 13 is operating. Store time series data.

<Replacement process of noise removal device 30A>
Next, the operation related to the replacement process of the noise removal device 30A according to the second embodiment will be described.
FIG. 12 is a flowchart illustrating the replacement process of the noise removal device 30A. The flow shown here is repeatedly executed every time the noise removal device 30A detects the operation of the welding gun 13 based on the operation command output from the robot control device 20 to the robot 10.
Note that in the replacement process shown in FIG. 12, the processes in step S21 and step S22 are the same as the processes in step S11 and step S12 in the first embodiment in FIG. 7, and the description thereof will be omitted.

In step S23, the data replacement unit 301a converts the acceleration data of the section in which the welding gun 13 is not operating and in which the robot 10 is in the same posture as when the welding gun 13 is operating into a pseudo acceleration. Extract as data.

In step S24, the data replacement unit 301a replaces the pseudo acceleration data extracted in step S23 as acceleration data of the motion section.

In step S25, the data replacement unit 301a smoothes the acceleration data replaced in step S24 by applying an averaging filter around the joint. The data replacement unit 301a then outputs the acceleration data replaced with the pseudo acceleration data in the motion section to the robot control device 20.

As described above, the noise removal device 30A according to the second embodiment is configured to collect acceleration data of the operation section in which the welding gun 13 operates, among the acceleration data acquired from the acceleration sensor 100 installed on the welding gun 13 attached to the robot 10. Delete. The noise removal device 30A converts time-series data of acceleration data in a section in which the welding gun 13 is not operating and in which the robot 10 is in the same posture as when the welding gun 13 is operating into a pseudo acceleration. Extract as data. The noise removal device 30A replaces the extracted pseudo acceleration data as acceleration data of the motion section.
Thereby, the noise removal device 30A can remove noise generated due to the influence of the welding gun 13 even when the welding gun 13 is operated to measure the acceleration sensor 100.
The second embodiment has been described above.

Although the first embodiment and the second embodiment have been described above, the noise removal devices 30 and 30A are not limited to the above-described embodiments, and include modifications, improvements, etc. within the range that can achieve the purpose. .

<Modified example>
In the first and second embodiments described above, the noise removal devices 30 and 30A are exemplified as devices different from the robot control device 20, but some or all of the functions of the noise removal devices 30 and 30A can be performed on the robot. The control device 20 may be provided.

Note that each function included in the noise removal devices 30 and 30A according to the first embodiment and the second embodiment can be realized by hardware, software, or a combination thereof. Here, being realized by software means being realized by a computer reading and executing a program.
Further, each component included in the noise removal devices 30 and 30A can be realized by hardware including an electronic circuit, software, or a combination thereof.

The program can be stored and provided to the computer using various types of non-transitory computer readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tape, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), and CD-ROMs. R, CD-R/W, semiconductor memory (including, for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM). Programs may also be stored in various types of temporary computer-readable media. (Transitory computer readable medium). Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. Transient computer readable media include electrical wires, optical fibers, etc. The program can be supplied to the computer via a wired communication path or a wireless communication path.

Note that the step of writing a program to be recorded on a recording medium includes not only processes that are performed in chronological order, but also processes that are not necessarily performed in chronological order but are executed in parallel or individually. It also includes.

In other words, the noise removal device of the present disclosure can take various embodiments having the following configurations.

(1) The noise removal device 30 of the present disclosure is a noise removal device that removes noise from acceleration data of an acceleration sensor 100 installed in a welding gun 13 attached to a robot 10, and includes the motion of the welding gun 13. A data replacement unit 301 is provided that replaces the acceleration data of the acceleration sensor 100 in the section with pseudo acceleration data and outputs the data.
According to this noise removal device 30, even when the welding gun 13 is operated to measure the acceleration sensor 100, noise generated due to the influence of the welding gun 13 can be removed.

(2) In the noise removal device 30 described in (1), acceleration in a section where the welding gun 13 is not operating and the robot 10 is in the same posture as when the welding gun 13 is operating. The data replacement unit 301 further includes a storage unit 310 that stores frequency spectrum data obtained by Fourier analysis of the acceleration data of the sensor 100, and the data replacement unit 301 synthesizes a sine wave using the frequency spectrum data stored in the storage unit 310. It may also be used as pseudo acceleration data.
By doing so, noise in the operating section can be removed with high accuracy.

(3) In the noise removal device 30A described in (1), acceleration in a section where the welding gun 13 is not operating and the robot 10 is in the same posture as when the welding gun is operating. The storage unit 310a may further include a storage unit 310a that stores acceleration data of the sensor 100 as time-series data, and the data replacement unit 301a may use the time-series data stored in the storage unit 310a as pseudo acceleration data.
By doing so, noise in the operating section can be removed with high accuracy.

(4) In the noise removing device 30, 30A according to any one of (1) to (3), the operation of the welding gun 13 may be an operation based on an operation command signal for the welding gun 13.
By doing so, the operating range in which the welding gun 13 operates can be detected with high accuracy.

(5) In the noise removal device 30 described in (2), when synthesizing the sine wave, the data replacement unit 301 adjusts the phase of the sine wave so that it smoothly connects the motion section and the acceleration data of the adjacent section. You may.
By doing so, it is possible to smoothly connect the acceleration data between the motion section and the adjacent section.

(6) In the noise removal device 30A described in (3), the data replacement unit 301a converts the acceleration around the joint between the motion section and the adjacent section so that the motion section and the adjacent section are smoothly connected to the acceleration data of the adjacent section. An averaging filter may be applied to the data.
By doing so, it is possible to smoothly connect the acceleration data between the motion section and the adjacent section.

10 robot 20 robot control device 30, 30A noise removal device 100 acceleration sensor 300, 300a control section 301, 301a data replacement section 310, 310a storage section

Claims (5)

A noise removal device that removes noise from acceleration data of an acceleration sensor installed in a welding gun attached to a robot,
a data replacement unit that replaces the acceleration data of the acceleration sensor in the operation section in which the welding gun operated with pseudo acceleration data and outputs the pseudo acceleration data;
Frequency spectrum data obtained by Fourier analysis of acceleration data of the acceleration sensor in a section where the welding gun is not operating and the robot is in the same posture as when the welding gun is operating. and a storage unit for storing the information.
The data replacement unit is a noise removal device that synthesizes a sine wave using the frequency spectrum data stored in the storage unit to generate the pseudo acceleration data. A noise removal device that removes noise from acceleration data of an acceleration sensor installed in a welding gun attached to a robot,
a data replacement unit that replaces the acceleration data of the acceleration sensor in the operation section in which the welding gun operated with pseudo acceleration data and outputs the pseudo acceleration data;
a storage unit that stores acceleration data of the acceleration sensor as time-series data in a section in which the welding gun is not operating and in which the robot is in the same posture as when the welding gun is operating ; , comprising ;
The data replacement unit is a noise removal device that uses the time series data stored in the storage unit as the pseudo acceleration data. The noise removal device according to claim 1 or 2 , wherein the operation of the welding gun is an operation based on an operation command signal for the welding gun. 2. The noise removal device according to claim 1 , wherein the data replacement unit adjusts the phase of the sine wave so that it smoothly connects with acceleration data of an interval adjacent to the motion interval when synthesizing the sine wave. The data replacement unit applies an averaging filter to acceleration data around a joint between the motion section and the adjacent section so that the motion section and the acceleration data of the adjacent section are smoothly connected. The noise removal device according to item 2 .

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