Measuring device

Abstract

To provide a measuring device capable of executing appropriate correction processing corresponding to the actual temperature of a measurement execution unit.SOLUTION: A three-dimensional measuring instrument 1 (measuring device) comprises: a probe 10 (measurement execution unit) for executing measurement processing on a measurement object; an electrical unit 122 located in a section of the probe 10; a temperature sensor 124 provided to the electrical unit 122, for measuring a temperature and outputting a detection signal based on the temperature; and a controller 20 (measurement calculation unit) for calculating the measurement result of the measurement object. The controller 20 corrects the measurement value obtained by measurement processing and calculates a measurement result on the basis of a processing signal for which a low-pass filter is applied to the detection signal outputted from the temperature sensor 124.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a measurement device. [Background technology]

[0002] When measuring coordinates on the surface of an object to be measured using a measuring device, it is necessary to take into consideration dimensional fluctuations of the measuring device due to temperature changes. For example, Patent Document 1 describes a measuring device (three-dimensional measuring machine) in which a temperature sensor that measures the temperature of the probe is provided on the probe, and describes that temperature correction of the measurement data may be further performed based on the temperature difference between the measured probe temperature and a reference temperature (usually 20°C). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-181293 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the measuring device described above, the temperature of the probe is measured and a correction process based on the temperature is performed. Here, the probe may include a stylus, a support unit that supports the stylus, a mechanical unit that is provided inside the support unit and forms a stylus movement mechanism, a sensor unit, and an electrical unit. In this case, when electrical components provided in the electrical unit are energized, the electrical components become a heat source. However, as the probe moves away from the electrical component, which is a heat source, it takes longer for heat to propagate, so the temperature rise over time becomes slower, and the saturation temperature also decreases due to heat dissipation the further away from the electrical component. Therefore, when a temperature sensor is installed in the electrical component, which is a heat source, the overall probe elongation calculated from the temperature sensor's measurement value does not immediately match the actual overall probe elongation. For this reason, if correction is performed based on the temperature measured by the temperature sensor immediately after turning on the measuring device, for example, an appropriate correction process for the overall probe elongation cannot be performed, and it is necessary to wait until the temperature rise saturates.

[0005] It is also possible to provide a temperature sensor in each part of the probe and measure the temperature of each part of the probe separately, but in this case, it is necessary to secure space for the temperature sensors so that they do not interfere with the object to be measured or other parts of the measurement device. In addition, providing multiple temperature sensors increases the cost of the device, and wiring is required from each temperature sensor to the electrical components, which creates the problem of complicated wiring.

[0006] The above-mentioned problem is not limited to measurement devices equipped with a probe such as that described in Patent Document 1. Similar problems exist in other measurement devices that have a temperature sensor in an electrical component located in a measurement execution unit that performs measurement. For example, a length measuring machine that measures the length of an object measures the length of the object by moving a detection head, which is an electrical component, on a scale along the longitudinal direction. In such length measuring machines, a correction process may be performed to compensate for dimensional variations due to temperature changes in the scale. Here, if a temperature sensor is provided in an electrical component (e.g., a detection head) located slightly away from the scale whose temperature is to be measured, it takes time for the heat from the electrical component to propagate to the scale, as with the probe described above. This can cause a discrepancy between the overall elongation of the scale calculated from the temperature sensor's measurement value and the actual overall elongation of the scale. Therefore, appropriate temperature correction cannot be performed until the temperature rise in the electrical component and the scale reaches saturation.

[0007] An object of the present invention is to provide a measurement device that can perform an appropriate correction process corresponding to the actual temperature of a measurement execution section. [Means for solving the problem]

[0008] A measurement device according to a first aspect of the present disclosure comprises a measurement execution unit that performs a measurement process on an object to be measured, an electrical unit that is arranged in part of the measurement execution unit, a temperature sensor that is provided in the electrical unit and measures temperature and outputs a detection signal based on the measured temperature, and a measurement calculation unit that calculates a measurement result of the object to be measured, wherein the measurement calculation unit calculates the measurement result by correcting the measurement value obtained by the measurement process based on a processed signal that is obtained by applying a low-pass filter to the detection signal output from the temperature sensor.

[0009] In this configuration, the temperature sensor measures the temperature of the electrical component that is a heat source. For example, immediately after the power is turned on, the temperature of the temperature sensor changes abruptly. However, by applying a low-pass filter to the detection signal output from the temperature sensor, the detection signal, whose signal value changes abruptly in response to the abrupt temperature change, can be converted into a processed signal whose signal value changes gradually. As a result, by correcting the measurement value based on the processed signal, correction processing can be performed that corresponds to the gradual temperature change of the measurement component. In other words, appropriate correction processing can be performed that corresponds to the actual temperature of the measurement component.

[0010] In the measurement device of the above aspect, it is preferable that the low-pass filter is a filter program recorded in a memory unit, and the measurement calculation unit reads and executes the filter program recorded in the memory unit, thereby applying the low-pass filter to the detection signal output from the temperature sensor to calculate the processed signal.

[0011] This configuration eliminates the need for a low-pass filter circuit to process the temperature sensor signal, simplifying the configuration of the measurement device. Furthermore, the filter program can be easily updated, allowing for highly accurate measurement results even if the measurement device's installation environment changes or the measurement unit is replaced.

[0012] In the measurement device of the above aspect, the low-pass filter may be a low-pass filter circuit, the detection signal output from the temperature sensor may be input to the low-pass filter circuit, and the processed signal output from the low-pass filter circuit may be output to the measurement calculation unit.

[0013] In this case, the detection signal from the temperature sensor is processed by the low-pass filter circuit to generate a processed signal, so the measurement calculation unit does not need to perform calculation processing related to the low-pass filter, and the processing load related to calculations can be reduced.

[0014] In the measuring device of the above aspect, it is preferable that the measurement execution unit is a probe including a stylus that can contact the object to be measured and a support unit that holds the stylus, and that the electrical unit and the temperature sensor are provided inside the support unit. In a probe having such a stylus and support, the stylus is brought into contact with the object to be measured to perform the measurement. In a probe having a temperature sensor in the electrical component, the temperature of the electrical component, which is a heat source, is measured by the temperature sensor. However, since heat propagates through each part of the probe over time, the temperature rise over time is gradual, and the saturation temperature decreases with increasing distance from the electrical component due to heat dissipation. Therefore, the overall elongation of the probe due to temperature rise cannot be directly corrected from the steep temperature measured by the temperature sensor. In contrast, in this embodiment, the measurement value is corrected based on a processed signal obtained by applying a low-pass filter to the detection signal corresponding to the temperature measured by the temperature sensor. This allows for appropriate correction processing corresponding to the overall elongation of the probe, as in the above embodiment. Furthermore, in a configuration in which a temperature sensor is provided in the electrical component inside the support, as in this embodiment, the number of temperature sensors can be reduced compared to when temperature sensors are provided in each part of the probe, such as the stylus. This prevents interference between the temperature sensor and the object to be measured or other parts of the measuring device, and simplifies the wiring configuration of the temperature sensor. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing an example of a measurement device according to a first embodiment. [Figure 2] 5A to 5C are diagrams for explaining temperature changes in various parts of the probe of the present embodiment. [Figure 3] FIG. 10 is a diagram showing an example of overall elongation of a probe due to a temperature rise. [Figure 4] FIG. 4 is a diagram showing an example of the relationship between the temperature measured by the temperature sensor and the temperature based on the processed signal after low-pass filtering in the present embodiment. [Figure 5] FIG. 10 is a diagram showing an example of the amount of change in coordinates of measurement results with respect to elapsed time. [Figure 6] FIG. 10 is a schematic diagram showing an example of a measurement device according to a second embodiment. [Figure 7] FIG. 10 is a diagram illustrating an example of a low-pass filter circuit. [Figure 8] FIG. 10 is a schematic diagram showing an example of a measurement device according to a third embodiment. [Figure 9] FIG. 10 is a schematic diagram showing an example of a measurement device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] [First embodiment] Hereinafter, a measurement device according to a first embodiment of the present disclosure will be described. FIG. 1 is a schematic diagram of a coordinate measuring machine, which is an example of the measuring device of this embodiment. 1, the coordinate measuring machine 1 includes a probe 10, a controller 20, a PC 40, etc. The coordinate measuring machine 1 also includes a mounting stage (not shown) that holds an object to be measured, and a probe movement mechanism 30 that moves the probe 10 relative to the mounting stage in an X direction, a Y direction perpendicular to the X direction, and a Z direction perpendicular to the X and Y directions. The probe movement mechanism 30 is further provided with an X scale 31, a Y scale 32, and a Z scale 33 that measure the amount of movement in the X direction, the Y direction, and the Z direction, respectively.

[0017] The probe 10 corresponds to the measurement execution unit of the present disclosure, and includes a stylus 11 and a support unit 12 that supports the stylus 11. The stylus 11 has a shaft 111 and a tip ball 112 provided at the tip of the shaft 111. When measuring the shape of an object to be measured using the three-dimensional measuring machine 1, the probe moving mechanism 30 is controlled by the controller 20, whereby the probe 10 is moved within three-dimensional space and the tip ball 112 of the stylus 11 is moved along the surface of the object to be measured.

[0018] The support portion 12 movably supports the base end side (the end portion of the shaft portion 111 opposite to the tip ball 112) of the stylus 11. The support portion 12 is, for example, a cylindrical member having a predetermined diameter, and a mechanical portion 121 and an electrical portion 122 are provided inside the support portion 12. The mechanism 121 movably supports the stylus 11. That is, the mechanism 121 supports the stylus 11 movably within a predetermined range in the axial direction (Zp direction) of the stylus 11, the Xp direction perpendicular to the Zp direction, and the Yp direction perpendicular to the Xp and Zp directions. The mechanism 121 is also provided with a probe sensor (not shown), which measures the amount of movement of the stylus 11 in the Zp direction, Xp direction, and Yp direction as probe coordinates.

[0019] The electrical component section 122 is an electrical circuit board on which a temperature sensor 124 and other electrical components 123 are mounted. For example, the probe sensor and the temperature sensor 124 detect probe coordinates and measure temperatures.

[0020] The temperature sensor 124 is built into the support portion 12 of the probe 10 and is directly provided on the electrical component portion 122, which is an electrical component board. The temperature sensor 124 is a sensor that measures the temperature of the probe 10, which is the measurement execution unit. Here, a description will be given of the temperature rise in the probe 10. Fig. 2 is a diagram for explaining the temperature change in each part of the probe 10. Fig. 3 is a diagram showing an example of the overall elongation of the probe 10 due to a temperature rise. In the probe 10 of this embodiment, when electricity is applied to the electrical component 123 provided in the electrical equipment unit 122, the electrical component 123 becomes a heat source and the temperature rises. Since the temperature sensor 124 is provided in the electrical equipment unit 122 together with the electrical component 123, the temperature measured by the temperature sensor 124 is approximately the same as the temperature rise of the electrical component 123, and exhibits a steep temperature change as shown by line A in Fig. 2 . 2 indicates the temperature rise at a position on the electrical component 122 side of the mechanical unit 121, line C indicates the temperature rise on the stylus 11 side of the mechanical unit 121, and line D indicates the temperature rise of the stylus 11. As shown by lines A to D in FIG. 2, the heat generated in the electrical component 123 is propagated to each part of the probe 10 with a delay as the distance from the electrical component 122 increases, and the saturation temperature decreases as the distance from the electrical component 122 increases. In this way, the rate of temperature rise and the rising temperature differ at each part of the probe, and as a result, as shown in FIG. 3, the elongation of the entire probe 10 changes more slowly than the temperature measured by the temperature sensor 124.

[0021] Therefore, if the dimensional variation of the probe 10 due to temperature changes is corrected using the temperature measured by the temperature sensor 124 as is, the resulting value will differ from the correction based on the actual dimensional variation of the probe 10. Therefore, in this embodiment, a low-pass filter process is applied to the temperature measured by the temperature sensor 124 to calculate a correction value corresponding to the actual dimensional variation of the probe 10. Note that correction using a low-pass filter will be described later.

[0022] The controller 20 corresponds to the measurement calculation unit of the present disclosure, and controls the entire coordinate measuring machine 1, performs measurements on the workpiece using the probe 10, and outputs coordinate measurement results. The measurement calculation unit of the present disclosure may also be configured by the controller 20 and a PC 40, which will be described later. The controller 20 is configured to include at least a storage unit 21 that stores various programs and various data, and a processor 22 that implements various functions by reading and executing the programs recorded in the storage unit 21, for example. More specifically, the processor 22 functions as a measurement control unit 221, a measurement coordinate acquisition unit 222, a probe coordinate acquisition unit 223, a temperature acquisition unit 224, a filter application unit 225, and a probe coordinate correction unit 226 by loading and executing various programs.

[0023] The measurement control unit 221 controls the probe movement mechanism 30 to move the probe 10 relative to the object to be measured. For example, the measurement control unit 221 refers to design data related to the object to be measured and measurement coordinates measured by the measurement coordinate acquisition unit 222, and moves the probe 10 along a predetermined trajectory. Alternatively, the measurement control unit 221 may refer to probe coordinates measured by the probe coordinate acquisition unit 223 and control the probe movement mechanism 30 so that the probe depression amount is constant.

[0024] The measurement coordinate acquisition unit 222 acquires the measurement coordinates (X, Y, Z) of the probe 10 , that is, the movement amount of the probe 10 in the X, Y, and Z directions measured by the X scale 31 , the Y scale 32 , and the Z scale 33 . The probe coordinate acquisition unit 223 acquires the probe coordinates (Xp, Yp, Zp) measured by the probe sensor provided on the probe 10. The temperature acquisition unit 224 acquires a detection signal corresponding to the measured temperature output from the temperature sensor 124 .

[0025] The filter application unit 225 applies low-pass filtering to the detection signal acquired by the temperature acquisition unit 224, and outputs the signal after the low-pass filtering as a processed signal. That is, in this embodiment, the processor 22 functions as the filter application unit 225 by reading and executing a filter program recorded in the storage unit 21, and generates a processed signal from the detection signal by performing arithmetic processing based on the filter program. For example, a low-pass filter of the following formula (1) is used, where R is the detection signal output from the temperature sensor 124, Y is the processed signal, τ is the time constant of the low-pass filter, and s is the Laplace operator.

[0026]

number

[0027] The temperature measured by the temperature sensor 124 is T S , the temperature after low-pass filtering (temperature used for temperature correction processing) is TL If the sampling period of the detection signal output from the temperature sensor 124 is Δt, the following equation (2) is obtained from the above equation (1).

[0028]

number

[0029] In equation (2), n indicates the number of sampling measurements, and T L [n] is the temperature T after the nth low-pass filter processing L , T L [n-1] is the temperature T after the n-1th low-pass filter processing L , T S [n] is the temperature T measured by the temperature sensor 124 at the nth time S is.

[0030] FIG. 4 shows the temperature T S and the temperature T based on the processed signal after low-pass filtering. L 4 is a graph showing an example of the relationship between the temperature T S ,T L The relationship between temperature T S is the solid line, and the temperature T L is shown by a dashed line. As described above, when the power supply of the coordinate measuring machine 1 is switched on, the electrical components 123 of the electrical equipment unit 122 are energized, and the temperature rises as a result of the electrical components 123 acting as a heat source. Since the temperature sensor 124 is directly provided on the electrical equipment unit 122, the temperature T S rises and settles at a predetermined temperature.

[0031] On the other hand, the temperature T L is calculated as in equation (2) above, and the temperature T S The temperature rises more slowly than the normal temperature and settles at the specified temperature. Here, as can be seen by comparing Figures 3 and 4, the temperature T L has a shape corresponding to the overall elongation of the probe 10, and the temperature T L By performing the correction process based on this, it becomes possible to appropriately correct the dimensional fluctuation caused by the temperature rise of the probe 10.

[0032] The probe coordinate corrector 226 calculates the temperature T corresponding to the processed signal calculated by the filter applicator 225. L The corrected probe coordinates are output by correcting the probe coordinates based on the above. Note that in this embodiment, an example is shown in which the probe coordinates are used as measurement values ​​by the probe coordinate correction unit 226, and the probe coordinates are corrected to become the probe coordinates of the measurement results, but the present invention is not limited to this. For example, a value obtained by adding the probe coordinates to the measurement coordinates measured by the measurement coordinate acquisition unit 222 may be used as the measurement value, and a correction value may be added to this to obtain the measurement result. 5 is a diagram showing an example of the amount of change in the measurement results. In FIG. 5, the dashed line indicates the temperature T L The dashed line indicates the coordinate change of the measurement result after correction based on the temperature T S The solid line indicates the coordinate change amount of the measurement result after correction processing based on the above, and the solid line indicates the coordinate change amount of the measurement result before correction (when no correction is performed). In the example shown in FIG. 5, the measurement results show that when the power is switched from off to on, the electrical component 122 becomes a heat source and the temperature of each part of the probe 10 changes, causing the entire probe 10 to extend. At this time, as described above, the temperature T measured by the temperature sensor 124 S On the other hand, since the heat is transferred slowly to each part of the probe 10, the actual extension of the probe 10 changes slowly, and the measurement results also fluctuate slowly, as shown by the solid line in Figure 5. As can be seen from a comparison with Figure 4, the fluctuations in the measurement results are due to the temperature T L The shape is approximately the same as the temperature change.

[0033] The probe coordinate correcting unit 226 outputs the measurement result in which the measurement value has been corrected so as to cancel out the dimensional fluctuation of the probe 10 due to such temperature changes. Here, assuming that the temperature TS In the case of measurement results corrected based on this, the amount of correction becomes too large, especially immediately after the power is turned on, and the measurement results change significantly, as shown by the dashed line in Figure 5. After a certain time has passed, the temperature rise in each part of the probe 10 saturates and the overall elongation of the probe 10 settles to a certain value, so that after that certain time, the measurement results are properly corrected, but it takes time to obtain the proper measurement results. In contrast to this, in this embodiment, the temperature T L In this case, as shown by the dashed line in Figure 5, it is possible to make corrections according to the actual elongation of the probe 10, and it is possible to calculate appropriate measurement results with a significant reduction in waiting time or even no waiting time at all.

[0034] Although the above description has been made regarding the axial direction (Zp direction) of the probe 10 in which the amount of expansion and contraction due to temperature changes becomes large, similar correction may be performed for the Xp direction and the Yp direction.

[0035] [Shape calculation by PC] The PC 40 is communicatively connected to the coordinate measuring machine 1, and calculates the surface coordinates and surface shape of the workpiece based on the corrected probe coordinates corrected by the probe coordinate corrector 226 and the measurement coordinates measured by the X scale 31, Y scale 32, and Z scale 33. For example, when the probe 10 is moved to trace the surface of the workpiece, each coordinate of the trajectory of the contact position between the probe 10 and the tip ball 112 is calculated based on the corrected probe coordinates and the measurement coordinates.

[0036] [Effects of this embodiment] The coordinate measuring machine 1 of this embodiment comprises a probe 10 having a stylus 11 that performs measurement processing on a measured object, a support unit that holds the stylus 11, and a controller 20. The support unit 12 of the probe 10 also comprises an electrical equipment unit 122 that includes electrical components 123 that control the probe 10, and a temperature sensor 124 that is provided in the electrical equipment unit 122 and measures the temperature of the probe 10 and outputs a detection signal based on the measured temperature. The controller 20 then calculates the measurement result by correcting the measurement value obtained by measurement using the stylus 11 based on a processed signal that is obtained by applying a low-pass filter to the detection signal output from the temperature sensor 124.

[0037] In this embodiment, the measurement value is corrected based on the processed signal obtained by applying a low-pass filter to the detection signal to calculate the measurement result, making it possible to calculate the measurement result corresponding to the actual elongation of the entire probe 10, rather than a sudden temperature change of the temperature sensor 124. Therefore, even immediately after switching the power of the coordinate measuring machine 1 from off to on, the probe coordinate corrector 226 can output highly accurate corrected probe coordinates, and this allows the PC 40 to calculate the measurement result with little measurement error.

[0038] In this embodiment, the low-pass filter is a filter program recorded in the memory unit 21, and the processor 22 reads and executes the filter program to perform an arithmetic process of applying the low-pass filter to the detection signal output from the temperature sensor 124, thereby generating a processed signal. This eliminates the need for a separate low-pass filter circuit, simplifying the configuration of the coordinate measuring machine 1. Furthermore, such a configuration also makes it easy to update the filter program. For example, the filter program can be updated in response to changes in the installation environment of the coordinate measuring machine 1, replacement of the entire probe 10 or the stylus 11, etc., and the time constant τ can be updated to an optimal value as appropriate.

[0039] In this embodiment, a probe 10 having a stylus 11 that can contact the object to be measured and a support part 12 that supports the stylus 11 is used as the measurement execution part of this disclosure, and the electrical part 122 and the temperature sensor 124 are provided inside the support part 12 of the probe 10. As described above, such a probe 10 can perform appropriate correction processing for the overall elongation of the probe 10. Furthermore, since only a single temperature sensor 124 is required, the configuration can be simplified compared to a configuration in which a temperature sensor is provided in each part of the probe 10, such as the stylus 11, and the temperature sensor 124 does not interfere with the object to be measured or other parts of the coordinate measuring machine 1, and the wiring for the temperature sensor 124 can also be simplified.

[0040] [Second embodiment] Next, a second embodiment will be described. In the first embodiment, the low-pass filter is a software program, and the processor 22 of the controller 20 loads the filter program into the storage unit 21 and executes it, thereby functioning as a filter application unit 225 that applies (calculates) the low-pass filter to the detection signal output from the temperature sensor 124. In contrast, in the second embodiment, an example will be shown in which a low-pass filter circuit is used.

[0041] 6 is a diagram showing a schematic configuration of a coordinate measuring machine 1A of the second embodiment. Note that the same components as those in the first embodiment are given the same reference numerals, and the description thereof will be omitted or simplified. The coordinate measuring machine 1A of this embodiment has a probe 10, a controller 20, and a PC 40, similar to the first embodiment. In the probe 10 of this embodiment, the electrical circuit board 122 is further provided with a low-pass filter circuit 125. The detection signal output from the temperature sensor 124 is input to the low-pass filter circuit 125, and the processed signal output from the low-pass filter circuit 125 is input to the controller 20.

[0042] FIG. 7 shows an example of a low-pass filter circuit 125. The low-pass filter circuit 125 is not particularly limited, and for example, an RC low-pass filter circuit as shown in FIG. 7(A) can be used. Other examples include an LC low-pass filter circuit as shown in FIG. 7(B), a low-pass filter circuit using an operational amplifier as shown in FIG. 7(C), and an LR low-pass filter circuit as shown in FIG. 7(D). The examples of the low-pass filter circuit 125 shown in FIG. 7 have different time constants τ. However, any of the low-pass filter circuits 125 can process the detection signal input from the temperature sensor 124 into a processed signal as shown in FIG. 4 and output it.

[0043] In addition, in this embodiment, since the low-pass filter circuit 125 is provided, the processor 22 of the controller 20 does not need to function as the filter application unit 225. That is, in this embodiment, the processor 22 functions as a processed signal acquisition unit 224A instead of the temperature acquisition unit 224 of the first embodiment. The processed signal acquisition unit 224A acquires the processed signal input from the temperature sensor 124 to the controller 20 via the low-pass filter circuit 125, that is, the processed signal after low-pass filtering. Then, the probe coordinate correction unit 226 calculates the temperature T corresponding to the processed signal acquired by the processed signal acquisition unit 224A. L The measurement result is output after correcting the measurement value based on the above.

[0044] [Effects of this embodiment] The coordinate measuring machine 1A of the second embodiment can achieve the same effects as the first embodiment. In addition, in the coordinate measuring machine 1 of this embodiment, the low-pass filter circuit 125 processes the detection signal from the temperature sensor 124 to generate a processed signal, so that the load on the processor 22 related to the calculation processing can be reduced.

[0045] [Third embodiment] In the first embodiment, an example was shown in which the processor 22 of the controller 20 functions as the filter application unit 225. In contrast to this, in the third embodiment, a configuration in which the filter application unit is provided inside the probe 10 will be exemplified.

[0046] FIG. 8 is a diagram showing a schematic configuration of a coordinate measuring machine 1B according to the third embodiment. In the coordinate measuring machine 1B shown in Fig. 8, an arithmetic processing unit 126 is provided in the electrical equipment unit 122 of the probe 10. The arithmetic processing unit 126 executes a software program to function as a temperature acquisition unit 224 and a filter application unit 225. The functions of the temperature acquisition unit 224 and the filter application unit 225 are the same as those in the first embodiment. That is, the temperature acquisition unit 224 acquires a detection signal corresponding to the measured temperature output from the temperature sensor 124 and outputs the detection signal to the filter application unit 225. The filter application unit 225 applies low-pass filtering to the input detection signal and outputs the processed signal after the low-pass filtering to the controller 20. Similarly to the second embodiment, the processor 22 of the controller 20 functions as a processed signal acquisition unit 224A and acquires the processed signal after low-pass filtering. Then, the probe coordinate correction unit 226 calculates the temperature T L The measurement result is output after correcting the measurement value based on the above. In the third embodiment as described above, the same effects as those of the first and second embodiments can be achieved.

[0047] [Fourth embodiment] In the third embodiment, a configuration in which the filter application unit is provided inside the probe 10 is exemplified, but the filter application unit 225 may be provided anywhere in the coordinate measuring machine. In the fourth embodiment, an example in which the filter application unit 225 is provided in the PC 40 is shown.

[0048] FIG. 9 is a diagram showing a schematic configuration of a coordinate measuring machine 1C according to the fourth embodiment. 9, for example, a PC-side processor 41 provided in a PC 40 executes a software program to function as a filter application unit 225 and a probe coordinate correction unit 226. In this case, when a temperature acquisition unit 224 of the controller 40 acquires a detection signal corresponding to the temperature measured by the temperature sensor 124, the temperature acquisition unit 224 transmits the detection signal to the PC 40. The controller 20 also transmits the measurement coordinates acquired by the measurement coordinate acquisition unit 222 and the probe coordinates acquired by the probe coordinate acquisition unit 223 to the PC 40.

[0049] The filter application unit 225 of the PC 40 is the same as in the first embodiment, and when it receives a detection signal from the controller 20, it applies low-pass filtering to the detection signal to generate a processed signal. Then, when the probe coordinate corrector 226 receives the measurement coordinates and probe coordinates from the controller 20, it corrects the measurement values ​​and calculates the measurement results based on the processed signals after the low-pass filter processing. In the fourth embodiment as described above, the same effects as those of the first to third embodiments can be achieved.

[0050] [Variations] The present invention is not limited to the above-described embodiment, but also includes the following modifications within the scope of achieving the object of the present invention.

[0051] [Variation 1] In each of the above embodiments, the probe 10 having the stylus 11 is used as the measurement performing unit, and the temperature of the probe 10 is measured by a temperature sensor 124 provided in the electrical component 122 built into the support portion 12 of the probe 10, but this is not limited to this. For example, the temperatures of X scale 31, Y scale 32, and Z scale 33 in three-dimensional measuring machines 1, 1A, 1B, and 1C may be temperature corrected as the measurement execution unit. For example, X scale 31 is provided with a scale, and is also provided with an electrical component (detection head) that includes an encoder and the like that reads the scale of X scale 31. In this case, a temperature sensor is provided in the detection head, which is the electrical component, and a detection signal output from the temperature sensor is subjected to low-pass filtering to generate a processed signal, and the measurement value measured by X scale 31 is corrected based on the processed signal. By providing a temperature sensor in the electrical component, which is a heat source, the measurement value can be properly corrected for the overall elongation of X-scale 31 even if the temperature of the temperature sensor differs from the temperature of each part of X-scale 31. The same applies to the Y scale 32 and the Z scale 33.

[0052] Furthermore, while the above is an example of the X scale 31, Y scale 32, and Z scale 33 provided on the coordinate measuring machines 1, 1A, 1B, and 1C, the present invention can be similarly applied to other measuring devices. For example, in a length measuring machine that measures the length of an object in one direction (X direction), the length of the object is measured using a scale (measurement unit) arranged along the length direction. In this case, a temperature sensor may be provided in an electrical unit (e.g., a reader such as an encoder that reads the scale value) provided in part of the scale, and the detection signal output from the temperature sensor may be subjected to a low-pass filter to generate a processed signal, as in the first and second embodiments, and the length (measured value) measured by the scale may be corrected based on the processed signal.

[0053] [Variation 2] In the second embodiment, the low-pass filter circuit 125 is provided in the electrical component 122 built into the support portion 12 of the probe 10, but the present invention is not limited to this. The low-pass filter circuit may be located anywhere in the transmission circuit that transmits a signal from the temperature sensor 124 to the controller 20. For example, the low-pass filter circuit 125 may be located on a circuit board on which the processor 22 of the controller 20 is mounted, so that it is connected to an input terminal to which the detection signal from the temperature sensor 124 is input.

[0054] [Variation 3] In the first embodiment, the filter application unit 225 calculates the temperature T after low-pass filtering based on the formula (2). L However, the present invention is not limited to this formula. For example, instead of equation (2), a moving average as shown in the following equation (3) may be used.

[0055]

number

[0056] In addition, in the above embodiment, a backward difference method as shown in equation (2) is used as a method for converting an analog signal into a digital signal by low-pass filtering, but other methods such as bilinear transformation or impulse invariant methods may also be used. For example, in a first-order low-pass filter using bilinear transformation, the following equation (4) can be used.

[0057]

number

[0058] In equation (4), Δt is the sampling period and τ is the time constant, which determines the strength of the low-pass filter. The same applies to the third and fourth embodiments in which low-pass filtering is performed by executing a software program. [Industrial Applicability]

[0059] The present invention can be applied to a measuring device that measures the properties of an object to be measured. [Explanation of symbols]

[0060] 1, 1A, 1B, 1C... three-dimensional measuring machine (measuring instrument), 10... probe, 11... stylus (measurement execution unit), 12... support unit, 20... controller, 21... memory unit, 22... processor, 121... mechanical unit, 122... electrical unit, 123... electrical components, 124... temperature sensor, 125... low-pass filter circuit, 221... measurement control unit, 222... measurement coordinate acquisition unit, 223... probe coordinate acquisition unit, 224... temperature acquisition unit, 225... filter application unit, 226... probe coordinate correction unit.

Claims

1. a measurement execution unit that executes a measurement process on the object to be measured; an electrical equipment unit disposed in a part of the measurement execution unit; a temperature sensor provided in the electrical equipment unit, which measures a temperature and outputs a detection signal based on the measured temperature; a measurement calculation unit that calculates a measurement result of the object to be measured, the measurement calculation unit corrects the measurement value obtained by the measurement process based on a processed signal obtained by applying a low-pass filter to the detection signal output from the temperature sensor, and calculates the measurement result. Measuring equipment.

2. the low-pass filter is a filter program recorded in a storage unit, the measurement calculation unit reads and executes the filter program recorded in a storage unit to apply the low-pass filter to the detection signal output from the temperature sensor and calculates the processed signal; The measuring device according to claim 1 .

3. the low-pass filter is a low-pass filter circuit, The detection signal output from the temperature sensor is input to the low-pass filter circuit, and the processed signal output from the low-pass filter circuit is output to the measurement calculation unit. The measuring device according to claim 1 .

4. the measurement execution unit is a probe including a stylus that can come into contact with the object to be measured and a support unit that holds the stylus, The electrical component and the temperature sensor are provided inside the support. The measuring device according to claim 1 .

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