On-machine measuring device, on-machine measuring system, and on-machine measuring method

Abstract

The on-machine measuring device (50) that assists in abnormality detection includes an information collecting unit (52) that acquires a servo signal including at least the actual position of a machine tool (30) having a drive axis that operates in response to an output from a numerical control device (10) and a distance sensor signal that is the output of a distance sensor (40) installed on at least one of the drive axes, and outputs the acquired servo signal and distance sensor signal as a measurement signal during a measurement signal transmission period that is a transmission period of the measurement signal; a configuration information accepting unit (51) that accepts external input of machine configuration information including information on the coordinate system of the machine tool (30) and information on the amount of correction for the coordinate system; and a measurement result calculating unit (53) that calculates the shape of a workpiece (31) to be machined by the machine tool (30) based on the machine configuration information and the measurement signal.

Description

[Technical Field]

[0001] The present disclosure relates to an on-machine measuring device, an on-machine measuring system, and an on-machine measuring method used in a machine tool. [Background technology]

[0002] Conventionally, on-machine measurement has been performed on machine tools to inspect machining results such as workpiece dimensions on the machine tool. In on-machine measurement, it is necessary to handle axis position detection signals from a position detector that detects the position of the machine tool's feed axis and the angle of the rotation axis, and measurement signals from an on-machine measuring device that measures workpiece dimensions, etc., in a synchronized manner. For example, Patent Document 1 discloses a technology in which the machine tool's amplifier is used as an interface, and axis position detection signals and measurement signals are transmitted synchronously from the machine tool's amplifier to an external device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-279722 Summary of the Invention [Problem to be solved by the invention]

[0004] However, according to the above-mentioned conventional technology, because the axis position detection signals and measurement signals detected at the same timing are used, even if the sampling period of the on-machine measuring device is faster than the sampling period of the position detector, some of the measurement signals obtained by the on-machine measuring device will not be used. Therefore, with machine tools such as those in the above-mentioned conventional technology, there is a problem in that even if an on-machine measuring device with a fast sampling period is used, the performance of the on-machine measuring device cannot be fully utilized.

[0005] The present disclosure has been made in consideration of the above, and aims to provide an on-machine measurement device that can utilize measurement results that correspond to the performance of the measurement sensor used in on-machine measurement. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the on-machine measuring device of the present disclosure operates in response to an output from a numerical control device. Feed and rotary axes Machine tools with Axis position detection signal from a position detector that detects the position of the feed axis and the angle of the rotary axis Contains at least the information Actual position and, Feed shaft At least one of the axes is installed Distance sensor Measure the distance between the workpiece and the machine tool did The distance sensor signal and the measurement signal transmission period are acquired. Actual position and an information collecting unit that outputs a distance sensor signal as a measurement signal; and a coordinate system that is set in the machine tool. Feed and rotary axes The machine is characterized by having a configuration information receiving unit that receives external input of machine configuration information including information on a coordinate system that represents the relative positions of the distance sensor and the workpiece, and information on a correction amount that corrects geometric errors relative to the coordinate system, and a measurement result calculation unit that calculates the shape of the workpiece based on the machine configuration information and the measurement signal. [Effects of the Invention]

[0007] The on-machine measurement device of the present disclosure has the effect of being able to utilize measurement results that correspond to the performance of the measurement sensor used in on-machine measurement. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a configuration example of an on-machine measurement system according to an embodiment; [Figure 2] 1 is a flowchart showing the operation of an on-machine measurement system according to an embodiment; [Figure 3] FIG. 10 is a diagram showing an example of a measurement signal output from an information collection unit of an on-machine measuring device to a measurement result calculation unit according to an embodiment; [Figure 4]1 is a flowchart showing the operation of a measurement result calculation unit included in an on-machine measuring device according to an embodiment; [Figure 5] FIG. 1 is a first diagram showing the relationship between pieces of information included in machine configuration information set for a general machine tool; [Figure 6] FIG. 2 is a second diagram showing the relationship between the various pieces of information included in the machine configuration information set for a general machine tool. [Figure 7] FIG. 1 is a diagram showing an example of the configuration of a processing circuit that realizes an on-machine measurement system according to an embodiment when the processing circuit is realized by a processor and a memory. [Figure 8] FIG. 1 is a diagram showing an example of the configuration of a processing circuit when the processing circuit that realizes the on-machine measurement system according to the embodiment is realized by dedicated hardware. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an on-machine measurement device, an on-machine measurement system, and an on-machine measurement method according to embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0010] Embodiment FIG. 1 is a diagram showing an example of the configuration of an on-machine measurement system 60 according to this embodiment. The on-machine measurement system 60 is a system that measures the shape and the like of a workpiece 31 when a machine tool 30 processes the workpiece 31. The on-machine measurement system 60 includes a numerical control device 10, a servo control unit 20, a distance sensor 40, and an on-machine measurement device 50. The on-machine measurement device 50 includes a configuration information receiving unit 51, an information collecting unit 52, and a measurement result calculating unit 53. The on-machine measurement device 50 can assist in detecting abnormalities in the workpiece 31, the machine tool 30, etc. by measuring the shape and the like of the workpiece 31. FIG. 2 is a flowchart showing the operation of the on-machine measurement system 60 according to this embodiment.

[0011] Numerical control device 10 controls the operation of machine tool 30, which has an operating drive axis, to control the machining of workpiece 31. Based on a set program, numerical control device 10 outputs control signals to servo control unit 20 for controlling the operation of machine tool 30, including position commands, speed commands, and correction values ​​for geometric errors with respect to the coordinate system of machine tool 30 (step S11).

[0012] Servo control unit 20 outputs a servo signal including at least information on the actual position of the drive axis to the drive axis of machine tool 30 and information collection unit 52 of on-machine measuring device 50 in response to the output from numerical control device 10, i.e., the control signal output from numerical control device 10 (step S12). The servo signal may include information on the current that operates the drive axis of machine tool 30, a correction value for geometric error corresponding to the actual position of the drive axis of machine tool 30, etc.

[0013] 1, machine tool 30 has three drive axes and performs three-axis machining to machine workpiece 31 under the control of numerical control device 10. Note that machine tool 30 is not limited to the example in FIG. 1, and may have five drive axes and be configured to perform five-axis machining.

[0014] Distance sensor 40 is installed on at least one of the drive axes of machine tool 30, and measures the distance to a specified object, workpiece 31 in the example of FIG. 1. Distance sensor 40 outputs a distance sensor signal indicating the distance to the measured object, workpiece 31 in the example of FIG. 1, to information collection unit 52 of on-machine measuring device 50 (step S13). In the example of FIG. 1, one distance sensor 40 is installed on the drive axis of the Z axis of machine tool 30, but distance sensor 40 may also be installed on the drive axis of the X axis, the Y axis, etc.

[0015] The configuration information receiving unit 51 receives external input of machine configuration information about the machine tool 30, including information on the coordinate system of the machine tool 30 and information on the amount of correction for the coordinate system (step S14). The configuration information receiving unit 51 outputs the received machine configuration information to the measurement result calculation unit 53. Note that it is sufficient for the configuration information receiving unit 51 to be able to output the machine configuration information to the measurement result calculation unit 53 by the time the measurement result calculation unit 53 calculates the shape of the workpiece 31, as will be described later. Therefore, the operation of step S14 may be performed before the operation of step S13.

[0016] The information collecting unit 52 acquires, from the servo control unit 20, a servo signal including at least information on the actual position of the drive axis (step S15). The information collecting unit 52 also acquires, from the distance sensor 40, a distance sensor signal that is the output of the distance sensor 40 installed on at least one of the drive axes of the machine tool 30 (step S16). The information collecting unit 52 outputs the servo signal acquired from the servo control unit 20 and the distance sensor signal acquired from the distance sensor 40 as measurement signals to the measurement result calculating unit 53 (step S17). In the present embodiment, the information collecting unit 52 outputs, as measurement signals, the servo signal and the distance sensor signal acquired during a measurement signal transmission period, which is the transmission period of the measurement signal, to the measurement result calculating unit 53.

[0017] The measurement result calculation unit 53 acquires the machine configuration information from the configuration information receiving unit 51, and acquires the measurement signal from the information collecting unit 52. Based on the acquired machine configuration information and measurement signal, the measurement result calculation unit 53 calculates the shape of the workpiece 31 to be machined by the machine tool 30 (step S18).

[0018] Here, the measurement signal output by the information collecting unit 52 to the measurement result calculation unit 53 will be described. FIG. 3 is a diagram showing an example of the measurement signal output by the information collecting unit 52 of the on-machine measuring device 50 according to this embodiment to the measurement result calculation unit 53. In FIG. 3, the first row shows the timing at which the information collecting unit 52 sends the measurement signal to the measurement result calculation unit 53, the second row shows the timing at which the information collecting unit 52 acquires a servo signal from the servo control unit 20, and the third row shows the timing at which the information collecting unit 52 acquires a distance sensor signal from the distance sensor 40. Also, in FIG. 3, the fourth row shows the shape of the machined surface of the workpiece 31 and the timing at which the distance sensor 40 measured the distance between the distance sensor 40 and the machined surface of the workpiece 31. In the example of FIG. 3, the timing at which the distance sensor 40 measured the distance between the distance sensor 40 and the machined surface of the workpiece 31 is represented as a measurement point. In Figure 3, the measurement signal transmission period is the period between the transmission timing of the measurement signal two times before and the transmission timing of the measurement signal one time before, and the period between the transmission timing of the measurement signal one time before and the transmission timing of the measurement signal one time before is the measurement signal transmission period.

[0019] As shown in FIG. 3 , the information collecting unit 52 acquires a distance sensor signal at each distance sensor signal period during which the distance sensor 40 performs measurement. The information collecting unit 52 also acquires a servo signal at each servo signal period during which the servo control unit 20 outputs a servo signal, which is a period longer than the distance sensor signal period. The information collecting unit 52 outputs a measurement signal including at least one servo signal and two or more distance sensor signals acquired during the measurement signal transmission period from the transmission time of the previous measurement signal to the transmission time of the latest measurement signal. In the example of FIG. 3 , the two or more distance sensor signals are four distance sensor signals. In this way, the information collecting unit 52 can utilize all distance sensor signals without wasting a single one, regardless of the distance sensor signal period of the distance sensor 40, the servo signal period of the servo control unit 20, and the measurement signal transmission period of the information collecting unit 52. Note that in the example of FIG. 3 , the number of servo signals and the number of distance sensor signals included in each measurement signal are the same, but this is not limited to this. Depending on the distance sensor signal period and the measurement signal transmission period, the pattern may be, for example, such that the measurement signal in one transmission period contains three distance sensor signals, the measurement signal in the next transmission period contains four distance sensor signals, and the measurement signal in the next transmission period contains three distance sensor signals.

[0020] Next, a detailed description will be given of the operation of the measurement result calculation unit 53. Fig. 4 is a flowchart showing the operation of the measurement result calculation unit 53 provided in the on-machine measuring device 50 according to this embodiment. As described above, the measurement result calculation unit 53 acquires machine configuration information about the machine tool 30 from the configuration information receiving unit 51 (step S21).

[0021] The machine configuration information received by the configuration information receiving unit 51 will now be described. First, the information on the correction amount for the coordinate system of the machine tool 30, which is included in the machine configuration information, will be described. The correction amount information is used to correct geometric errors. Examples of geometric errors include deviation from perpendicularity that occurs when the machine tool 30 is assembled and deviation due to the machine tool 30's own weight. These correction amounts are set based on results obtained during periodic inspections of the machine tool 30 before or after shipment. Furthermore, when the machine tool 30 is a multi-axis machine tool such as a five-axis machining center, the geometric errors may include errors caused by the position and inclination of the center line of the rotation axis of the drive shaft, the installation position and inclination of the workpiece 31, and the like. In this embodiment, the method for determining the geometric errors is not particularly limited. For example, the correction amount may be set based on errors determined by a measurement method such as that described in Japanese Patent No. 4,959,028.

[0022] The machine configuration information also includes at least rotational axis configuration information, which is information indicating whether the rotational axis, which is the drive axis of machine tool 30, is installed on the side of workpiece 31 or the side of the spindle, and information indicating which of the three orthogonal axes, X, Y, and Z, the rotational axis rotates around; three-dimensional vectors of the X, Y, and Z axes, which indicate the distances along each of the three orthogonal axes from the machine origin, which is the tip of the spindle when the three orthogonal axes, X, Y, and Z, are set at the specified origin of machine tool 30, to the specified table origin of the table on which workpiece 31 is placed; and a sensor length, which is the reference length of distance sensor 40. The spindle is the main drive axis of machine tool 30. In the information indicating which of the three orthogonal axes, X, Y, and Z, the rotational axis rotates around, the X axis is generally represented as the A axis, the Y axis as the B axis, and the Z axis as the C axis. The rotation axes include linear axes whose drive shafts move linearly due to the rotation of a motor (not shown), and rotation axes whose drive shafts move in rotation due to the rotation of a motor (not shown). The table origin is, for example, the central coordinate of the table on which the workpiece 31 is placed. The three-dimensional vector of the X, Y, and Z axes is also referred to as workpiece coordinate origin information. The sensor length is the distance from the tip of the spindle to the surface to be measured when the distance sensor 40 is installed at the tip of the spindle and the surface to be measured is set so that the measured distance value (described later) becomes the reference value. For example, the reference value is 0 if the distance sensor 40 has an equal range for positive and negative values. The surface to be measured is the reference surface where the measurement result of the distance sensor 40 becomes 0.

[0023] Fig. 5 is a first diagram showing the relationship between each piece of information included in machine configuration information set for a general machine tool. Fig. 6 is a second diagram showing the relationship between each piece of information included in machine configuration information set for a general machine tool. The relationship between each piece of information included in the machine configuration information is as shown in Fig. 5 or Fig. 6.

[0024] Returning to the description of FIG. 4, the measurement result calculation unit 53 acquires a measurement signal from the information collection unit 52 (step S22). Each time the measurement result calculation unit 53 acquires a measurement signal, it calculates the shape of the workpiece 31, which is the object to be machined by the machine tool 30, based on the acquired machine configuration information and the measurement signal, as in step S18 described above. Specifically, the measurement result calculation unit 53 subtracts the geometric error correction amount from the actual position of each drive axis of the machine tool 30 to calculate the pre-correction actual position of each drive axis (step S23). The measurement result calculation unit 53 adds the value of the distance sensor signal included in the acquired measurement signal to the sensor length to calculate the measured distance value (step S24). The measurement result calculation unit 53 calculates the actual speed of each drive axis of the machine tool 30 based on the actual position of the drive axis of the machine tool 30 included in the first measurement signal, which is a measurement signal, and the second measurement signal, which is a measurement signal acquired after the first measurement signal. The measurement result calculation unit 53 calculates the interpolated actual position, which is the pre-correction actual position of the servo at the time when the distance sensor signal is output from the distance sensor 40, i.e., the time measured by the distance sensor 40, based on the actual speed of the target drive shaft, the actual position of the target drive shaft, the sampling period of the distance sensor 40, and the sampling period of the servo signal in the servo control unit 20 (step S25).

[0025] The measurement result calculation unit 53 performs coordinate conversion processing using the measured distance value obtained by adding the value of the distance sensor signal to the sensor length, the actual position after interpolation, and the mechanical configuration information of the machine tool 30 to calculate coordinates corresponding to the tool center point of the machine tool 30 (step S26). The measurement result calculation unit 53 calculates coordinates corresponding to the tool center point of the machine tool 30 for all measurement points shown in the fourth row of FIG. 3. In this embodiment, the coordinate conversion processing is not particularly limited. For example, the measurement result calculation unit 53 can perform the coordinate conversion processing by performing processing such as that described in "Development of Tool Center Point Trajectory Analysis Technology for Simultaneous 5-Axis Control, JTEKT Corporation, Kenji Hamada, Atsushi Saito, Toshiyuki Okita, Proceedings of the 2012 Japan Society for Precision Engineering Spring Meeting Academic Lecture Series, pp. 839-840." Note that the tool length in the cited document corresponds to the measured distance value in this embodiment. While the tool length in the cited document is a constant value, the measured distance value in this embodiment is assumed to change over time. The measurement result calculation unit 53 performs the operation of step S26 for all of the interpolated actual positions calculated in step S25. The measurement result calculation unit 53 outputs the coordinates obtained in the operation of step S26 as the measurement results, i.e., the shape of the workpiece 31 (step S27). This allows the measurement result calculation unit 53 to calculate the shape of the workpiece 31 using all of the measurement points shown in the fourth row of Fig. 3.

[0026] Next, the hardware configuration of the on-machine measurement system 60 according to this embodiment will be described. In the on-machine measurement system 60, the distance sensor 40 is a sensor capable of measuring the distance from the distance sensor 40 to the workpiece 31. The numerical control device 10, the servo control unit 20, and the on-machine measurement device 50 are realized by a processing circuit. The processing circuit may be a memory that stores a program and a processor that executes the program stored in the memory, or may be dedicated hardware. The processing circuit is also called a control circuit.

[0027] FIG. 7 is a diagram showing an example of the configuration of a processing circuit 90 when the processing circuit for implementing the on-machine measurement system 60 according to this embodiment is implemented by a processor 91 and a memory 92. The processing circuit 90 shown in FIG. 7 is a control circuit and includes a processor 91 and a memory 92. When the processing circuit 90 is configured with the processor 91 and the memory 92, each function of the processing circuit 90 is implemented by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 92. The processing circuit 90 implements each function by having the processor 91 read and execute the program stored in the memory 92. That is, the processing circuit 90 includes the memory 92 for storing a program that results in the processing of the on-machine measurement system 60. This program can also be said to be a program for causing the on-machine measurement system 60 implemented by the processing circuit 90 to execute the program. This program may be provided by a storage medium on which the program is stored, or by other means such as a communication medium.

[0028] Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor), etc. Furthermore, the memory 92 is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), or an EEPROM (registered trademark) (Electrically EPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisk, or a DVD (Digital Versatile Disc).

[0029] FIG. 8 is a diagram showing an example of the configuration of a processing circuit 93 when the processing circuit that realizes the on-machine measurement system 60 according to this embodiment is realized by dedicated hardware. The processing circuit 93 shown in FIG. 8 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The processing circuit 93 may be realized in part by dedicated hardware and in part by software or firmware. In this way, the processing circuit 93 can realize each of the above-described functions by dedicated hardware, software, firmware, or a combination thereof.

[0030] As described above, according to this embodiment, in on-machine measurement system 60, configuration information receiving unit 51 of on-machine measuring device 50 receives external input of machine configuration information, information collecting unit 52 outputs servo signals obtained from servo control unit 20 and distance sensor signals obtained from distance sensor 40 as measurement signals, and measurement result calculating unit 53 calculates the shape of workpiece 31, which is an object to be machined by machine tool 30, based on the machine configuration information and the measurement signals. At this time, information collecting unit 52 acquires distance sensor signals at each distance sensor signal period in which distance sensor 40 performs measurement, acquires servo signals at each servo signal period which is longer than the distance sensor signal period, and outputs a measurement signal including at least one servo signal and two or more distance sensor signals acquired during the measurement signal transmission period from the transmission time of the previous measurement signal to the transmission time of the latest measurement signal.

[0031] This allows the on-machine measuring device 50 to use measurement results that correspond to the performance of the distance sensor 40 used in on-machine measurement. Even if the cycle at which the distance sensor signal is output from the distance sensor 40 is faster than the cycle at which the servo signal is output from the servo control unit 20 and the cycle at which the information collection unit 52 outputs the measurement signal, the on-machine measuring device 50 can use the distance sensor signal output from the distance sensor 40 without wasting it, and can therefore calculate the shape of the workpiece 31 with high accuracy.

[0032] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention. [Explanation of symbols]

[0033] 10 Numerical control device, 20 Servo control unit, 30 Machine tool, 31 Workpiece, 40 Distance sensor, 50 On-machine measuring device, 51 Configuration information reception unit, 52 Information collection unit, 53 Measurement result calculation unit, 60 On-machine measuring system, 90, 93 Processing circuit, 91 Processor, 92 Memory.

Claims

1. an information collecting unit which acquires a servo signal including at least information on an actual position of a drive shaft of a machine tool having a drive shaft which operates in response to an output from a numerical control device, and a distance sensor signal which is the output of a distance sensor which is installed on at least one of the drive shafts and measures a distance between the drive shaft and a workpiece which is an object to be machined by the machine tool, and outputs the servo signal and the distance sensor signal acquired during a measurement signal transmission period which is a transmission period of the measurement signal as the measurement signal; a configuration information receiving unit that receives an external input of machine configuration information including information on a coordinate system set in the machine tool that represents relative positions of the drive shaft, the distance sensor, and the workpiece, and information on a correction amount that corrects a geometric error with respect to the coordinate system; a measurement result calculation unit that calculates a shape of the workpiece based on the machine configuration information and the measurement signal; An on-machine measuring device comprising:

2. the information collecting unit acquires the distance sensor signal for each distance sensor signal period in which the distance sensor performs measurement, acquires the servo signal for each servo signal period that is a period longer than the distance sensor signal period, and outputs the measurement signal including at least one of the servo signal and two or more of the distance sensor signals acquired during the measurement signal transmission period from the transmission time of the previous measurement signal to the transmission time of the latest measurement signal.

2. The on-machine measuring device according to claim 1 .

3. the measurement result calculation unit calculates an actual speed of each drive axis of the machine tool based on an actual position of the drive axis contained in a first measurement signal which is the measurement signal and a second measurement signal which is the measurement signal acquired after the first measurement signal, and calculates an interpolated actual position of the target drive axis at the time when the distance sensor signal is output from the distance sensor based on the actual speed of the target drive axis, the actual position of the target drive axis, the sampling period of the distance sensor, and the sampling period of the servo signal; 3. The on-machine measuring device according to claim 1 or 2.

4. The machine configuration information includes at least rotation axis configuration information consisting of information indicating whether a rotation axis, which is the drive axis of the machine tool, is installed on the side of the workpiece or on the side of the spindle, which is the main drive axis of the machine tool, and information indicating which of three orthogonal axes the rotation axis rotates around, a three-dimensional vector indicating the distance of each of the three orthogonal axes from the machine origin, which is the tip of the spindle, to the specified table origin of the table on which the workpiece is placed when the three orthogonal axes are set to the specified origin of the machine tool, and a sensor length, which is the reference length of the distance sensor.

4. The on-machine measuring device according to claim 3.

5. the measurement result calculation unit performs a coordinate conversion process using a measured distance value obtained by adding the value of the distance sensor signal to the sensor length, the actual position after interpolation, and the machine configuration information to calculate coordinates corresponding to a tool tip point of the machine tool, and outputs the coordinates as the shape of the workpiece.

5. The on-machine measuring device according to claim 4.

6. a numerical control device that outputs a control signal for controlling the operation of a machine tool having an operating drive axis; a servo control unit that outputs a servo signal including at least information on an actual position of the drive axis of the machine tool in response to the control signal output from the numerical control device; a distance sensor that is installed on at least one of the drive shafts and that measures a distance between the drive shaft and a workpiece that is an object to be machined by the machine tool and outputs a distance sensor signal; an information collecting unit that acquires the servo signal and the distance sensor signal, and outputs the servo signal and the distance sensor signal acquired during a measurement signal transmission period that is a transmission period of a measurement signal as the measurement signal; a configuration information receiving unit that receives an external input of machine configuration information, the input including information on a coordinate system set in the machine tool that represents relative positions of the drive shaft, the distance sensor, and the workpiece, and information on a correction amount that corrects a geometric error with respect to the coordinate system; a measurement result calculation unit that calculates a shape of the workpiece based on the machine configuration information and the measurement signal; An on-machine measurement system comprising:

7. A first step in which a numerical control device outputs a control signal for controlling the operation of a machine tool having an operating drive axis; a second step in which a servo control unit outputs a servo signal including at least information on an actual position of the drive axis of the machine tool in response to the control signal output from the numerical control device; a third step in which a distance sensor is installed on at least one of the drive shafts to measure a distance between the drive shaft and a workpiece to be machined by the machine tool and output a distance sensor signal; a fourth step in which an information collecting unit acquires the servo signal and the distance sensor signal, and outputs, as the measurement signal, the servo signal and the distance sensor signal acquired during a measurement signal transmission period that is a transmission period of a measurement signal; a fifth step in which a configuration information receiving unit receives an external input of machine configuration information, the machine configuration information including information on a coordinate system set in the machine tool and representing relative positions of the drive shaft, the distance sensor, and the workpiece, and information on a correction amount for correcting a geometric error with respect to the coordinate system; A sixth step in which a measurement result calculation unit calculates a shape of the workpiece based on the machine configuration information and the measurement signal; An on-machine measurement method comprising: