JP6834854B2 - Work detection device, work detection method and computer program - Google Patents

Description

The present invention relates to a work detection device for detecting the position of a work, a work detection method, and a computer program.

Conventionally, in a processing apparatus or the like, a technique of detecting the position of a workpiece to be processed by contact with a moving probe has been known.

For example, Patent Document 1 describes in a detection device having a contact and a detection means for detecting electrical continuity when the contact contacts a detection point, the contact moves in a first direction toward the detection point. When the continuity is detected, the contactor moves in the second direction opposite to the first direction. Disclosed is a detection method for determining that a conductive liquid may have adhered to such a detection point when the contactor maintains continuity even if it moves by a predetermined threshold value or more in the second direction.

Japanese Unexamined Patent Publication No. 2016-142638

On the other hand, even if the contact between the probe and the work can be detected, if a disturbance occurs at the time of the detection, the disturbance may have an influence on the detection result. Such detection results lead to inaccurate work position detection. The detection method of Patent Document 1 cannot solve such a problem.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a work detection device and a work detection method capable of more accurately detecting the position of a work in consideration of the influence of disturbance. There is.

The work detection device according to the present invention has a probe that detects the presence or absence of contact with the work within a predetermined range and emits a contact signal indicating the detection result, a disturbance detection unit that detects whether or not there is a disturbance, and the acquired contact signal. When indicating that there has been contact with the work, the coordinates for determining the coordinates of the work based on the determination result of the disturbance determination unit for determining whether or not there was a disturbance within the previous predetermined time and the determination result of the disturbance determination unit. It is characterized by having a determination unit.

In the present invention, when the acquired contact signal indicates that there has been contact with the work, the disturbance determination unit determines whether or not there has been a disturbance within the previous predetermined time. The coordinate determination unit determines the coordinates of the work based on the determination result of the disturbance determination unit. Therefore, the influence of disturbance can be taken into consideration when determining the coordinates of the work.

The work detection device according to the present invention includes a drive motor for driving the probe, and the disturbance includes torque related to the drive motor.

In the present invention, the disturbance detection unit detects disturbance including torque related to the drive motor of the probe. The disturbance determination unit determines whether or not there is a disturbance including torque related to the drive motor within the previous predetermined time. Therefore, when determining the coordinates of the work, it is possible to consider the influence of disturbance due to the torque related to the drive motor of the own machine.

The work detection device according to the present invention is characterized by including an invalidation unit that invalidates the acquired contact signal when the disturbance determination unit determines that there is a disturbance.

In the present invention, when the disturbance determination unit determines that there is a disturbance, the invalid unit invalidates the acquired contact signal. Therefore, the influence of the disturbance can be eliminated and the coordinates of the work can be accurately determined.

The work detection device according to the present invention includes a transmission unit that changes the moving speed of the probe when the disturbance determining unit determines that there is a disturbance, and when the moving speed of the probe changes, the probe is said to be predetermined. It is characterized in that the detection in the range is performed again.

In the present invention, when the disturbance determination unit determines that there is a disturbance, the probe changes the moving speed and executes the detection again.

The work detection device according to the present invention is characterized in that, when the moving speed of the probe is changed, the disturbance determination unit determines whether or not there is a disturbance within a time longer than the predetermined time.

In the present invention, when the moving speed of the probe is changed, the detection sensitivity of the probe may also be affected. Therefore, the time range related to the determination of the disturbance determination unit is changed according to the change in the moving speed of the probe.

The work detection method according to the present invention is a work detection method including a probe that detects the presence or absence of contact with a work within a predetermined range and emits a contact signal indicating the detection result, and a storage unit that stores the contact signal and the detection result of disturbance. In the work detection method for detecting the position of the work by the device, when the contact signal acquired from the storage unit indicates that there was contact with the work, it is determined whether or not there was a disturbance within the previous predetermined time. It is characterized by including a disturbance determination step to be performed, and a step of detecting the position of the work based on the determination result in the disturbance determination step.

The computer program according to the present invention comprises a work detection device including a probe that detects the presence or absence of contact with a work within a predetermined range and emits a contact signal indicating a detection result, and a disturbance detection unit that detects whether or not there is a disturbance. In a computer program that causes a computer to detect the position of a work, a case where the acquisition step of causing the computer to acquire the contact signal and a case where the contact signal acquired in the acquisition step indicates that the computer has contacted the work. , A disturbance determination step for determining whether or not there was a disturbance within the previous predetermined time, and a coordinate determination step for causing the computer to determine the coordinates of the work based on the determination result in the disturbance determination step. It is characterized by.

In the present invention, when the acquired contact signal indicates that there has been contact with the work, it is determined whether or not there has been a disturbance within the previous predetermined time, and based on the result of such determination, the work. Determine the coordinates of. Therefore, the influence of disturbance can be taken into consideration when determining the coordinates of the work.

According to the present invention, when detecting the contact between the probe and the work, the position of the work can be detected more accurately in consideration of the influence of disturbance.

It is a block diagram which shows the main part structure of the work detection apparatus which concerns on Embodiment 1. FIG. It is a functional block diagram which shows the composition of the main part of the data processing part of the work detection apparatus which concerns on Embodiment 1. FIG. It is explanatory drawing which outlines the process of the work position detection in the work detection apparatus which concerns on Embodiment 1. FIG. It is explanatory drawing which outlines the process of the work position detection in the work detection apparatus which concerns on Embodiment 1. FIG. It is a flowchart explaining the process of the work position detection in the work detection apparatus which concerns on Embodiment 1. FIG. It is a functional block diagram which shows the main part structure of the data processing part of the work detection apparatus which concerns on Embodiment 2. FIG. It is a block diagram which shows the main part structure of the work detection apparatus which concerns on Embodiment 4.

Hereinafter, the work detection device and the work detection method according to the embodiment of the present invention will be described with reference to the drawings. For example, the work detection device according to the embodiment is provided in the machine tool, detects the position of the work to be machined on the table of the machine tool, and measures the machining reference point and the like.

(Embodiment 1)
FIG. 1 is a configuration diagram showing a main configuration of a work detection device according to a first embodiment. In FIG. 1, reference numeral 100 represents a work detection device according to the present embodiment. The work detection device 100 according to the present embodiment includes a probe 10 and a main body 20. The work detection device 100 performs contact detection in which the probe 10 moves within a predetermined range and detects the presence or absence of contact between the probe 10 and the work W. The work detection device 100 specifies the coordinates of the work W using the result of contact detection. Hereinafter, these processes are also referred to as work position detection.

The probe 10 includes a housing 1 and a stylus 3 having a contact ball 2 at the tip. The housing 1 holds the stylus 3. The stylus 3 is, for example, perpendicular to the table. As described above, the stylus 3 can be deformed and returned from the state perpendicular to the table in the direction along the upper surface of the table.

The probe 10 includes a communication unit 11 and a sensor 12.
The sensor 12 detects vibration, deformation, or the like of the stylus 3 when detecting contact. That is, the sensor 12 detects vibration, deformation, etc. of the stylus 3 and detects whether or not the contact ball 2 has come into contact with the work W. When the contact ball 2 comes into contact with the work W, the sensor 12 emits an analog detection signal to that effect.
The communication unit 11 converts the analog detection signal into a digital signal and transmits it to the main body 20 by wire or wirelessly. In such a digital signal, the case where the contact sphere 2 comes into contact with the work W is represented by "1", and the case where the contact sphere 2 does not contact the work W is represented by "0". Hereinafter, such a digital signal will be referred to as a contact signal.

The main body 20 includes a communication unit 21, a disturbance detection unit 22, a drive mechanism 23, a data processing unit 24, an output unit 25, and a storage unit 26.
The communication unit 21 receives a contact signal from the probe 10. The storage unit 26 stores the contact signal received by the communication unit 21.

The disturbance detection unit 22 detects whether or not there is a disturbance at the time of contact detection. The disturbance includes, for example, friction torque, torque due to the influence of gravity, torque due to interference of other shafts, and torque due to the influence of other proximal devices. These values can be calculated if the speed of the drive motor that drives the probe 10 and the posture of the probe 10 are determined. Further, the disturbance detection unit 22 according to the present embodiment also detects the torque due to the influence of the drive motor that drives the probe 10 as a disturbance.
When the value of the detected disturbance is equal to or greater than a predetermined threshold value, the disturbance detection unit 22 determines that there is a disturbance. Based on the result of such determination, the disturbance detection unit 22 emits a disturbance signal indicating the presence or absence of disturbance detection. The storage unit 26 stores such a disturbance signal. The disturbance signal is a digital signal indicated by "1" when there is a disturbance and "0" when there is no disturbance.

The drive mechanism 23 (drive motor) is a moving mechanism for moving the probe 10 in the X-axis (for example, left-right direction), Y-axis (for example, front-back direction), and Z-axis (for example, up-down direction) on the table. including. The probe 10 is set in the holder and moved by the holder in the same manner as the tool. Therefore, the moving mechanism includes, for example, a servomotor, a servo amplifier that controls the servomotor, and the like for moving the holder.
The output unit 25 outputs predetermined information to the user of the work detection device 100. The output unit 25 may be, for example, a speaker, a lamp, a display unit, or the like.

The storage unit 26 is a non-volatile storage medium such as a flash memory, EEPROM (registered trademark), HDD, MRAM (magnetoresistive memory), FeRAM (ferroelectric memory), or OUM. The storage unit 26 stores, for example, a control program for detecting the work position. Further, the storage unit 26 stores the contact signal received by the communication unit 21 and the disturbance signal representing the result of the disturbance detection by the disturbance detection unit 22.

In the work position detection process, the data processing unit 24 determines the position of the work W (X-axis, Y) based on the contact signal and disturbance signal stored by the storage unit 26 and the rotational position of the servomotor that can be acquired from the servo amplifier. Axis and Z-axis coordinates) are specified.
The probe 10 and the disturbance detection unit 22 continuously emit a contact signal and a disturbance signal in a time series. The storage unit 26 stores the contact signal and the disturbance signal each time. On the other hand, in the work position detection process, in consideration of the burden of data processing, the contact signal and the disturbance signal are acquired from the storage unit 26 at regular time intervals, that is, at regular intervals, and the work position is detected.
The work detection device 100 according to the present embodiment is not limited to this. The probe 10 may be configured to emit a contact signal at regular intervals.

FIG. 2 is a functional block diagram showing a main configuration of the data processing unit 24 of the work detection device 100 according to the first embodiment. The data processing unit 24 includes a CPU 241, an acquisition unit 242, a disturbance determination unit 243, a coordinate determination unit 244, an invalidation unit 245, and a notification unit 246.

The CPU 241 loads and executes a control program stored in advance in a ROM (not shown) on a RAM (not shown) to control various hardware described above.

The acquisition unit 242 periodically reads the contact signal from the storage unit 26 and acquires it. One cycle is, for example, 125 μs.
When the disturbance determination unit 243 indicates that the acquisition contact signal acquired by the acquisition unit 242 has contacted with the work W, whether or not there was a disturbance within a predetermined time before the acquisition unit 242 acquires the contact signal. To judge. Specifically, when the acquisition contact signal is "1", the acquisition unit 242 determines whether or not there is a disturbance within a predetermined time (for example, one cycle) before acquiring the contact signal. The disturbance determination unit 243 makes such a determination based on the disturbance signal stored by the storage unit 26.
The work detection device 100 according to the present embodiment is not limited to this. The predetermined time may be 2 cycles or 3 cycles.

The coordinate determination unit 244 determines the coordinates of the work W based on the acquisition contact signal, the determination result of the disturbance determination unit 243, and the rotation position of the servomotor acquired from the servo amplifier.
Specifically, the coordinate determination unit 244 determines the coordinates of the work W based on the rotation position of the servomotor when the acquisition contact signal is "1" and there is no disturbance within the predetermined time before that. To do.

The invalidation unit 245 invalidates the acquisition contact signal according to the determination result of the disturbance determination unit 243. For example, when the disturbance determination unit 243 determines that there is a disturbance within a predetermined time before the acquisition of the contact signal, the invalidation unit 245 invalidates the acquisition contact signal. At this time, the coordinate determination unit 244 does not determine the coordinates of the work W.

The notification unit 246 notifies the user based on the determination result of the disturbance determination unit 243. For example, when the disturbance determination unit 243 determines that there is a disturbance within a predetermined time before the acquisition of the contact signal, the user is notified via the output unit 25 to that effect. Specifically, an alarm is sounded, a lamp is turned on, or an error occurrence is displayed.

3 and 4 are explanatory views schematically explaining the work position detection process in the work detection device 100 according to the first embodiment. FIG. 3 shows the case where there is no disturbance, and FIG. 4 shows the case where there is a disturbance. In FIGS. 3 and 4, the broken line indicates the period for acquiring the contact signal.

The probe 10 performs contact detection while moving at a constant velocity, and emits a detection signal indicating a detection result. The probe 10 transmits a contact signal based on the detection signal to the main body 20, and the storage unit 26 stores it in time series. When there is contact with the work W, the probe 10 transmits a contact signal of "1" to the main body 20. When there is no contact with the work W, the probe 10 transmits a contact signal of "0" to the main body 20. In addition, the storage unit 26 stores disturbance signals indicating the presence or absence of disturbance detection in time series.

The work detection device 100 according to the first embodiment periodically acquires a contact signal from the storage unit 26 and determines whether or not the value is “1”. When it is "1", it is determined whether or not there is a disturbance within a predetermined time before acquiring the contact signal. That is, it is confirmed whether the value within the predetermined time before acquiring the contact signal in the disturbance signal is "0" or "1".

When the value of the disturbance signal is "0" (see the hatched portion in FIG. 3), it indicates that there was no disturbance within a predetermined time before acquiring the contact signal. In other words, when the contact with the work W was detected, there was no disturbance, so such a detection result is accurate. Therefore, the coordinates of the work W are determined based on the rotation position of the servo motor at the time of acquiring the contact signal.

When the value of the disturbance signal is "1" (see the hatched portion in FIG. 4), it indicates that there was a disturbance within a predetermined time before acquiring the contact signal. In other words, when the contact with the work W is detected, there is a disturbance, so that the detection result may be inaccurate. Therefore, the acquired contact signal is invalidated.

FIG. 5 is a flowchart illustrating a work position detection process in the work detection device 100 according to the first embodiment.

First, the CPU 241 instructs the disturbance detection unit 22 to detect the disturbance, and the disturbance detection unit 22 starts the disturbance detection (step S101). Next, the CPU 241 starts contact detection (step S102). That is, the CPU 241 instructs the probe 10 to start contact detection, and the probe 10 detects the presence or absence of contact with the work W while moving on the table in the X-axis, Y-axis, or Z-axis directions.

The CPU 241 instructs the time counting unit (not shown) to measure the time, and determines whether or not one cycle (125 μs) has elapsed based on the time measuring result of the time measuring unit (step S103).
When the CPU 241 determines that one cycle has not elapsed (step S103: NO), the CPU 241 repeats such determination until it determines that one cycle has elapsed.
When the CPU 241 determines that one cycle has elapsed (step S103: YES), the acquisition unit 242 reads the contact signal from the storage unit 26 and acquires it (step S104).

The CPU 241 determines whether or not there is contact with the work W, that is, whether or not the value of the acquired contact signal is "1" (step S105).
When the CPU 241 determines that the value of the acquisition contact signal is not "1" (step S105: NO), the CPU 241 returns the process to step S103.
When the CPU 241 determines that the value of the acquisition contact signal is "1" (step S105: YES), the CPU 241 temporarily stops the contact detection (step S106). Therefore, the probe 10 stops.

Next, the disturbance determination unit 243 determines whether or not there is a disturbance within one cycle before acquiring the acquisition contact signal (step S107).
When the disturbance determination unit 243 determines that there is no disturbance within one cycle before acquiring the acquisition contact signal (step S107: NO), the coordinate determination unit 244 determines the X-axis and Y based on the rotation position of the servomotor. The coordinates of the work W on the axis or the Z axis are determined (step S108).

When the disturbance determination unit 243 determines that there is a disturbance within one cycle before acquiring the acquisition contact signal (step S107: YES), the invalid unit 245 invalidates the acquisition contact signal, that is, the contact signal acquired in step S104. (Step S109).
Further, the notification unit 246 notifies the user that there is a disturbance via the output unit 25 (step S110).

The work detection device 100 according to the present embodiment is not limited to the above description. If the invalidation unit 245 invalidates such an acquisition contact signal in step S109, the process may return to step S102. That is, when the contact signal acquired by the invalid unit 245 is invalidated, the contact detection may be performed again.

As described above, in the work detection device 100 according to the present embodiment, even if it is detected that the probe 10 is in contact with the work W, if there is a disturbance within a predetermined time before that, such a detection result is obtained. Disable as inaccurate. Therefore, it is possible to prevent the work position detection that is likely to be inaccurate in advance and improve the accuracy of the work position detection.

(Embodiment 2)
FIG. 6 is a functional block diagram showing a main configuration of the data processing unit 24 of the work detection device 100 according to the second embodiment. Similar to the first embodiment, the data processing unit 24 includes a CPU 241, an acquisition unit 242, a disturbance determination unit 243, a coordinate determination unit 244, an invalidation unit 245, and a notification unit 246. Further, the data processing unit 24 has a speed change unit 247. The CPU 241 and the acquisition unit 242, the disturbance determination unit 243, the coordinate determination unit 244, the invalidation unit 245, and the notification unit 246 are the same as those in the first embodiment, and thus the description thereof will be omitted.

When the disturbance determination unit 243 determines that there is a disturbance within a predetermined time before the acquisition of the contact signal, the transmission unit 247 changes the moving speed of the probe 10 in the contact detection. That is, the transmission unit 247 changes the moving speed of the probe 10 and changes the torque by the drive motor that drives the probe 10. This is because when the torque of the drive motor is reduced, the determination result of the presence or absence of disturbance by the disturbance detection unit 22 may change. The moving speed of the probe 10 can be changed by the transmission unit 247 controlling the servo amplifier of the drive mechanism 23.

When the speed change unit 247 changes the moving speed of the probe 10 after detecting the contact with the work W in the predetermined range (contact detection), the probe 10 re-executes the contact detection in the predetermined range. That is, in the example of FIG. 5, after step S109, the speed change unit 247 changes the moving speed of the probe 10, and the process returns to step S102.

As described above, in the work detection device 100 according to the present embodiment, even if it is detected that the probe 10 is in contact with the work W, if there is a disturbance within a predetermined time before that, the moving speed of the probe 10 Is changed and such contact detection is performed again. Therefore, it is possible to prevent the work position detection that is likely to be inaccurate in advance and improve the accuracy of the work position detection.

The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

(Embodiment 3)
In the data processing unit 24 of the work detection device 100 according to the third embodiment, the data processing unit 24 has the CPU 241 and the acquisition unit 242, the disturbance determination unit 243, the coordinate determination unit 244, and the invalid unit 245, as in the second embodiment. , Notification unit 246, and speed change unit 247. The CPU 241 and the acquisition unit 242, the disturbance determination unit 243, the coordinate determination unit 244, the invalid unit 245, the notification unit 246, and the transmission unit 247 are the same as those in the first and second embodiments, and thus the description thereof will be omitted.

In the work detection device 100 according to the third embodiment, when the moving speed of the probe 10 in the contact detection is changed, the disturbance determination unit 243 determines whether or not there is a disturbance from before the predetermined time.
For example, when the disturbance determination unit 243 determines that there is a disturbance within a predetermined time (for example, within one cycle) before the contact signal is acquired, the transmission unit 247 changes the moving speed of the probe 10. After that, when the contact detection is performed again, the disturbance determination unit 243 determines whether or not there is a disturbance from the predetermined time, that is, before one cycle.

Specifically, when the moving speed of the probe 10 becomes high (for example, 500 mm / sec), the vibration / deformation of the stylus 3 of the probe 10 becomes large. Therefore, the disturbance determination unit 243 determines, for example, whether or not there is a disturbance within three cycles before acquiring the contact signal. In this case, the disturbance determination unit 243 determines that there is a disturbance only when all the values of the disturbance signals are "1" for three cycles.

Further, when the moving speed of the probe 10 becomes slow (for example, 50 mm / sec), the vibration / deformation of the stylus 3 of the probe 10 becomes small. Therefore, the disturbance determination unit 243 may be configured to determine whether or not there is a disturbance within one cycle before the acquisition of the contact signal, as in the case before the movement speed change of the probe 10.

As described above, in the work detection device 100 according to the present embodiment, even if the probe 10 detects that it has come into contact with the work W, if there is a disturbance within a predetermined time before that, the moving speed of the probe 10 Is changed and such contact detection is performed again. In this case, the disturbance determination unit 243 determines whether or not there is a disturbance before the predetermined time. Therefore, it is possible to prevent the work position detection that is likely to be inaccurate in advance and improve the accuracy of the work position detection.

The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The acquisition unit 242, the disturbance determination unit 243, the coordinate determination unit 244, the invalidation unit 245, the notification unit 246, and the transmission unit 247 may be configured by hardware logic, and the CPU 241 executes a predetermined program. As a result, it may be constructed as software.

(Embodiment 4)
FIG. 7 is a configuration diagram showing a main configuration of the work detection device according to the fourth embodiment. In the work detection device 100 of the present embodiment, a computer program for performing the operation can be provided by a portable recording medium A such as a USB (Universal Serial Bus) memory via the I / F 27. Further, the work detection device 100 of the present embodiment can also download the computer program from an external device (not shown) via the communication unit 21. The contents will be described below.

The work detection device 100 includes an exterior (or interior) recording medium reading device (not shown), and the recording medium reading device acquires the contact signal, and the acquired contact signal is in contact with the work. In the case of indicating that, a portable recording medium A in which a program or the like for determining whether or not there was a disturbance within the previous predetermined time is determined and the coordinates of the work are determined based on the result of such determination is inserted. Then, for example, the CPU 241 installs this program in the ROM (not shown). Such a program is loaded into RAM (not shown) and executed. As a result, it functions as the work detection device 100 of the present embodiment.

The recording medium may be a so-called program medium, and may be a tape system such as a magnetic tape or a cassette tape, a magnetic disk such as a flexible disk or a hard disk, or an optical disk system such as a CD-ROM / MO / MD / DVD. It may be a card system such as an IC card (including a memory card) / optical card, or a medium that fixedly carries a program code including a semiconductor memory such as a mask ROM, EPROM, EEPROM, or flash ROM.

The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

10 Probe 23 Drive mechanism (drive motor)
26 Storage unit 100 Work detector 241 CPU
243 Disturbance judgment unit 245 Invalid unit 247 Transmission unit W work

Claims (7)

A probe that detects the presence or absence of contact with the work within a predetermined range and emits a contact signal indicating the detection result.
A disturbance detection unit that detects whether or not there was a disturbance,
When the acquired contact signal indicates that there was contact with the work, a disturbance determination unit that determines whether or not there was a disturbance within the previous predetermined time, and a disturbance determination unit.
A work detection device including a coordinate determination unit that determines the coordinates of the work based on the determination result of the disturbance determination unit. A drive motor for driving the probe is provided.
The work detection device according to claim 1, wherein the disturbance includes a torque related to the drive motor. The work detection device according to claim 1 or 2, further comprising an invalidation unit that invalidates the acquired contact signal when the disturbance determination unit determines that there is a disturbance. When the disturbance determination unit determines that there is a disturbance, the transmission unit is provided to change the moving speed of the probe.
The work detection device according to any one of claims 1 to 3, wherein when the moving speed of the probe is changed, the probe performs the detection again in the predetermined range. The work detection device according to claim 4, wherein when the moving speed of the probe is changed, the disturbance determination unit determines whether or not there is a disturbance within a time longer than the predetermined time. The position of the work is determined by a work detection device including a probe that detects the presence or absence of contact with the work within a predetermined range and emits a contact signal indicating the detection result, and a storage unit that stores the contact signal and the detection result of disturbance. In the work detection method to be detected,
When the contact signal acquired from the storage unit indicates that there has been contact with the work, a disturbance determination step for determining whether or not there has been a disturbance within the previous predetermined time, and a disturbance determination step.
A work detection method including a step of detecting the position of the work based on a determination result in the disturbance determination step. The position of the work is set on a computer that constitutes a work detection device including a probe that detects the presence or absence of contact with the work within a predetermined range and emits a contact signal indicating the detection result, and a disturbance detection unit that detects whether or not there is a disturbance. In the computer program to be detected
The acquisition step of causing the computer to acquire the contact signal,
When the contact signal acquired in the acquisition step indicates that the computer has contacted the work, the disturbance determination step for causing the computer to determine whether or not there was a disturbance within the previous predetermined time,
A computer program comprising causing a computer to execute a coordinate determination step of determining the coordinates of the work based on the determination result in the disturbance determination step.

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