Measurement device

Abstract

A measurement device according to the present disclosure comprises: a coordinates value calculation unit for calculating, on the basis of a signal inputted from a measurement instrument, a coordinate value of a position at which the shape of a measurement surface of an object under measurement changes; a measurement information recording unit for recording measurement information concerning the time interval at which the shape of the measurement surface of the object under measurement changes; and a speed improperness determining unit for determining, if the time interval at which the shape of the measurement surface of the object under measurement changes as recorded by the measurement information recording unit is shorter than a prescribed first threshold defined in advance, that the relative speed between the measurement surface of the object under measurement and the measurement instrument is improper. Upon determining that the relative speed is improper, the measurement device communicates that the evaluation of the measurement surface of the object under measurement is not being correctly carried out.

Description

Measuring device

[0001] This disclosure relates to a measuring device.

[0002] There is a technique for evaluating shape by analyzing a signal input from a measuring instrument and calculating the coordinate values ​​at the rising and falling edges of that signal (for example, Patent Document 1). Such a technique is used, for example, when machining a workpiece with an uneven surface, such as a gear, to detect the rising and falling edges of the gear teeth and evaluate the shape of the gear teeth.

[0003] Japanese Patent Publication No. 2020-055072

[0004] When measuring the shape of an object, increasing the relative speed between the measuring surface and the measuring instrument can shorten the cycle time for evaluating the shape of the measuring surface. For example, when evaluating the shape of gear teeth, increasing the rotational speed of the gear when measuring the tooth irregularities with the measuring instrument can shorten the cycle time for evaluating the gear's shape. However, a predetermined processing time is required for the measuring device to analyze the signal from the instrument and calculate the coordinate values ​​of the tooth's rising and falling positions. Therefore, if the rising and falling positions occur consecutively within the processing time for coordinate value calculation, it may become impossible to accurately calculate each coordinate value. For this reason, it is desirable to be able to determine whether the relative speed between the measuring surface and the measuring instrument is controlled according to the processing capacity of the measuring device.

[0005] The measuring device according to this disclosure determines whether the relative speed between the measuring surface of the object to be measured and the measuring instrument is appropriate based on the processing capacity of the measuring instrument and the measurement information. The above problem is solved by monitoring the signal input from the measuring instrument and determining whether the coordinate values ​​of the position where the shape of the workpiece changes at the current speed can be correctly calculated.

[0006] Furthermore, one aspect of the present disclosure is a measuring device comprising: a coordinate value calculation unit that calculates coordinate values ​​of the position where the shape of the measuring surface has changed based on a signal input from a measuring instrument that moves its relative position to the measuring surface of the object to be measured and measures the change in the shape of the measuring surface; a measurement information recording unit that records measurement information relating to the time interval at which a shape change occurs on the measuring surface of the object to be measured; and a speed inaccuracy determination unit that determines that the relative speed between the measuring surface of the object to be measured and the measuring instrument is incorrect if the time interval at which a shape change occurs on the measuring surface of the object to be measured, as recorded by the measurement information recording unit, is shorter than a predetermined first threshold, wherein the speed inaccuracy determination unit notifies that the measuring surface of the object to be measured has not been properly evaluated.

[0007] This is a schematic hardware configuration diagram of a measuring device according to the first embodiment of this disclosure. This is a schematic diagram of gear shape measurement using the measuring device according to this embodiment. This is a block diagram showing the schematic functions of the measuring device according to the first embodiment of this disclosure. This is a graph showing an example of a series of distance data calculated based on a signal input from a measuring instrument. This is a graph showing another example of a series of distance data calculated based on a signal input from a measuring instrument. This is a block diagram showing the schematic functions of a measuring device according to the second embodiment of this disclosure. This is a schematic diagram of work surface shape measurement using the measuring device according to this embodiment.

[0008] [First Embodiment] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 is a schematic hardware configuration diagram showing the main parts of a measuring device according to the first embodiment of the present disclosure. In this embodiment, a measuring device 1 that measures the rise and fall positions of the teeth of a gear to be measured will be described as an example.

[0009] The CPU 11 in the measuring device 1 according to this embodiment is a processor that controls the measuring device 1 as a whole. The CPU 11 reads the system program stored in the ROM 12 via the bus 22 and controls the entire measuring device 1 according to the system program. The RAM 13 temporarily stores temporary calculation data, display data, and various data input from external sources.

[0010] The non-volatile memory 14 is composed of, for example, a memory backed up by a battery (not shown) or an SSD (Solid State Drive), and its stored state is maintained even when the power to the measuring device 1 is turned off. The non-volatile memory 14 stores programs and data read from external devices 32 via the interface 15, programs and data input via the input device 31, and data calculated based on signals input from the measuring instrument 35. The programs and data stored in the non-volatile memory 14 may be expanded into the RAM 13 when executed or used. In addition, various system programs, such as known analysis programs, are pre-written in the ROM 12.

[0011] Interface 15 is an interface for connecting the CPU 11 of the measuring device 1 to an external device 32 such as a USB device. From the external device 32, control programs and various parameters used to control the industrial machine 3 can be read, for example. Furthermore, control programs and various parameters edited within the measuring device 1 can be stored in an external storage means via the external device 32.

[0012] The display device 30 outputs and displays data loaded into memory, data obtained as a result of the execution of programs and system programs, etc., via the interface 18. In addition, the input device 31, which consists of a keyboard and a pointing device, transmits commands and data based on the operator's operations to the CPU 11 via the interface 19.

[0013] The measuring instrument 35 is connected to the measuring device 1 via the interface 20. The measuring instrument 35 may be, for example, a distance detector that emits laser light and detects distance by the reflected light. It may also be an ultrasonic sensor or the like. The interface 20 converts the signal input from the measuring instrument 35 into distance data and passes it to the CPU 11.

[0014] The motor 37 is connected to the measuring device 1 via the interface 21. The interface 21 drives the motor 37 based on control commands for the motor 37 input from the CPU 11. The motor 37 has a built-in position and speed sensor and feeds back position and speed feedback signals from this sensor. The position and speed of the motor 37 are then controlled based on the control commands and feedback signals.

[0015] Figure 2 is a schematic diagram of gear shape measurement using the measuring device 1 according to this embodiment. The measuring device 1 is connected to a measuring instrument 35 and a motor 37. The gear to be measured is mounted on a predetermined rotating shaft. The rotating shaft rotates when power is transmitted from the motor 37 via a power transmission member such as a pulley or a rotating belt. The measuring instrument 35 is positioned at a predetermined distance d in the circumferential direction from the center of rotation of the gear, and is directed toward the center of rotation of the gear.

[0016] By arranging the components in this manner, the motor 37 is driven to rotate the gear, and the signal from the measuring instrument 35 is analyzed. For example, when the gear tooth tip is at the measurement position, the distance from the measuring instrument 35 to the tooth tip is measured, and when the gear tooth root is at the measurement position, the distance from the measuring instrument 35 to the tooth root is measured. The measuring instrument 35 outputs a signal indicating the measured distance to the measuring device 1. The measuring device 1 can calculate the distance from the gear's center of rotation to the measurement position by subtracting the distance measured by the measuring instrument 35 from the distance d between the measuring instrument 35 and the gear's center of rotation.

[0017] Figure 3 is a schematic block diagram showing the functions of the measuring device 1 according to this embodiment. Each function of the measuring device 1 according to this embodiment is realized by the CPU 11 of the measuring device 1 shown in Figure 1 executing a system program and controlling the operation of each part of the measuring device 1.

[0018] The measuring device 1 of this embodiment includes a coordinate value calculation unit 110, a measurement information recording unit 120, and a speed fraud determination unit 130.

[0019] The coordinate value calculation unit 110 calculates the coordinate values ​​of the rising and falling positions of the gear teeth based on the signals input from the measuring instrument 35. The coordinate value calculation unit 110 stores, for example, a series of distance data calculated based on the signals input from the measuring instrument 35 in a predetermined buffer memory. If a predetermined number or more series of distance data indicating a shorter distance than that measured up to that point follow, the coordinates of the rising position of the teeth may be calculated from these series of distance data. Alternatively, if a predetermined number or more series of distance data indicating a longer distance than that measured up to that point follow, the coordinates of the falling position of the teeth may be calculated from these series of distance data. The coordinate value calculation unit 110 displays the calculated coordinate values ​​on the display device 30.

[0020] Figure 4 is a graph showing an example of a series of distance data calculated based on signals input from the measuring instrument 35. The measuring device 1 receives signals from the measuring instrument 35 at predetermined intervals. The distance data calculated based on the input signals is stored in the buffer memory. The buffer memory stores a predetermined number of the most recent distance data. At this time, the coordinate value calculation unit 110 monitors the series of distance data stored in the buffer memory. Then, after a series of distance data for a predetermined distance d1 has passed (in Figure 4, at time t i ~t (i+2) ) and the distance changes significantly (in Figure 4, at time t (i+3) ~t (i+4) ), followed by a series of distance data showing a distance d2 that is shorter than a predetermined distance d1 (in Figure 4, at time t (i+5) ~t (i+7) When such a trend of distance change is detected, the coordinate value calculation unit 110 calculates the coordinate value of the rising position of the gear teeth based on the position of the motor 37 at any time between the time when distance d1 was last detected and the time when distance d2 was first detected. The coordinate value of the rising position can be appropriately calculated based on the position of the motor 37 at that time and the reduction ratio of the power transmission member, etc.

[0021] FIG. 5 is a graph showing another example of a series of distance data calculated based on the signal input from the measuring device 35. The coordinate value calculation unit 110 monitors the series of distance data stored in the buffer memory, and after a series of distance data of a predetermined distance d2 continues (in FIG. 5, time t j ~t (j+2) ), the distance changes significantly (in FIG. 5, time t (ｊ+3) ~t (ｊ+4) ), and then a series of distance data indicating a distance d1 longer than the predetermined distance d ２ continues (in FIG. 5, time t (j+5) ~t (j+7) ). When such a distance change tendency is detected, the coordinate value calculation unit 110 calculates the coordinate value of the tooth falling position of the gear based on the position of the motor 37 at any time between the time when the distance d2 was last detected and the time when the distance d1 was first detected. The coordinate value of the falling position can be appropriately calculated based on the position of the motor 37 at that time and the reduction ratio of the power transmission member, etc.

[0022] Note that the calculation methods of the rising position and the falling position described in FIGS. 4 and 5 are examples. Other known calculation methods of the rising position and the falling position can be appropriately used.

[0023] The coordinate value calculation unit 110 executes the calculation process of the coordinate values of the rising position and the falling position as exemplified above for the time assigned for each control cycle. If it takes a predetermined or more time for the calculation process of the coordinate value of one rising position or falling position, for example, while detecting the rising position of the tooth of the gear and calculating the coordinate of the rising position, the measurement position of the measuring device 35 may pass the next falling position. And when the coordinate value calculation unit 110 finishes calculating the coordinate of the rising position, the distance data recording the falling position disappears from the buffer memory. In such a case, the coordinate value of the falling position cannot be correctly calculated. Therefore, the measurement information recording unit 120 and the speed irregularity determination unit 130 detect that such a situation has occurred and notify the user.

[0024] The measurement information recording unit 120 records measurement information relating to the time interval at which a change in the shape of the workpiece occurs. The measurement information may be, for example, the time interval at which a change in the shape of the workpiece occurs, calculated based on a signal input from the measuring instrument 35. In this case, the measurement information recording unit 120 monitors the signal input from the measuring instrument 35, for example, and the distance calculated based on the signal is set to a predetermined time t. v Within a predetermined distance d v The measurement information recording unit 120 may determine that a shape change has occurred when only a certain amount of change has occurred. The measurement information recording unit 120 then stores, for example, the time when the shape change was detected in the RAM 13 or non-volatile memory 14. The difference between the time when the shape change was detected and the time when the shape change was detected immediately before is recorded as measurement information related to the time interval in which the shape change occurs. Only the shortest time interval needs to be recorded as measurement information related to the time interval in which the shape change occurs. The measurement information recording unit 120 will record the time interval in which the detected shape change occurs as a predetermined time t. err In the following cases, recording of the time interval may be omitted. This configuration allows for handling situations where changes in the workpiece shape are falsely detected due to disturbances such as chattering.

[0025] Furthermore, the measurement information may be calculated based on the number of times the shape of the workpiece changes within a predetermined time. In this case, the measurement information recording unit 120 prepares, for example, a counter for recording the number of shape changes in the RAM 13 or non-volatile memory 14. Then, from the start of measurement until a predetermined time t p Each time a shape change is detected during this time, the counter is incremented. Then, for a predetermined time t p The value of the counter after the predetermined time t p The value obtained by dividing by is recorded as measurement information relating to the time interval in which the shape change occurs. The measurement information recording unit 120 records the time interval in which the detected shape change occurs as a predetermined time t. errThe following cases may be excluded from the count of shape changes. This configuration allows for handling situations where changes in the workpiece shape are falsely detected due to disturbances such as chattering.

[0026] Furthermore, the measurement information may be calculated based on the shape specifications of the workpiece and the speed of the motor 37. The measurement information recording unit 120 obtains the speed of the motor 37 either directly from the motor 37 or from the commanded speed to the motor 37. Then, based on the obtained speed of the motor 37, the reduction ratio of the power transmission member, and the shape specifications of the workpiece (for example, in the case of a gear, the root circumference, tip circumference, root diameter, tip diameter, number of teeth, tooth pressure, circle pitch, etc.), it calculates the time interval at which a change in the shape of the workpiece occurs and records the calculated value as measurement information.

[0027] The speed fraud determination unit 130 determines the relative speed between the workpiece and the measuring instrument based on the measurement information stored by the measurement information recording unit 120. The speed fraud determination unit 130 determines, for example, if the time interval at which a change in the shape of the workpiece occurs is a predetermined threshold t set in advance. th If the relative speed between the workpiece and the measuring instrument is shorter than a predetermined threshold t, it may be determined that the relative speed is incorrect. th The value of can be calculated in advance by conducting experiments or similar methods. Also, the predetermined time t p This can be set in advance, or a predetermined threshold c may be set in advance. th The value may also be calculated based on the speed of the motor 37. If the speed error detection unit 130 determines that the relative speed between the workpiece and the measuring instrument is incorrect, it notifies the coordinate value calculation unit 110 that the coordinate values ​​have not been calculated correctly and the measurement target has not been evaluated correctly. Upon receiving the notification, the coordinate value calculation unit 110 displays on the display device 30 the calculated coordinate values ​​along with the fact that the coordinate values ​​have not been calculated correctly and the measurement target has not been evaluated correctly. At this time, an alarm may also be output.

[0028] [Correction based on Rule 91, October 29, 2024] The measuring device 1 according to the present embodiment having the above configuration determines whether the coordinate values of the position where the shape of the measurement surface of the measurement object has changed can be accurately calculated, and if they cannot be accurately calculated, notifies the user to that effect. The user who has received the notification can adjust the relative speed between the workpiece and the measuring instrument and measure the shape of the workpiece again. As a result, it becomes possible to use the correct measurement result of the workpiece.

[0029] [Second Embodiment] Hereinafter, a measuring device according to the second embodiment of the present disclosure will be described with reference to the drawings. The measuring device 1 according to the present embodiment has the same hardware configuration as the measuring device according to the first embodiment.

[0030] FIG. 6 shows schematically in block diagram form the functions of the measuring device 1 according to the present embodiment. Each function of the measuring device 1 according to the present embodiment is realized by the CPU, 11 of the measuring device 1 shown in FIG. 1 executing a system program and controlling the operation of each part of the measuring device 1.

[0031] The measuring device 1 according to the present embodiment further includes a motor speed calculation unit 140 in addition to the coordinate value calculation unit 110, the measurement information recording unit 120, and the speed irregularity determination unit 130. The coordinate value calculation unit 110 and the measurement information recording unit 120 according to the present embodiment have the same functions as the respective functions of the measuring device 1 according to the first embodiment.

[0032] When the speed irregularity determination unit 130 according to the present embodiment determines that the relative speed between the workpiece and the measuring instrument is irregular, it issues a command to the motor speed calculation unit 140 to control the speed of the motor.

[0033] When the motor speed calculation unit 140 is commanded by the speed irregularity determination unit 130 to control the speed of the motor, it acquires measurement information related to the time interval during which a shape change occurs from the measurement information recording unit 120. Then, a predetermined threshold value t thCalculate the ratio of the acquired measurement information with respect to [the relevant value]. Then, multiply the calculated ratio by the speed of the currently commanded motor 37, and set the result as the new speed of the motor. At this time, the motor speed calculation unit 140 may further subtract a predetermined margin value v m set in advance from the calculated motor speed. The motor speed calculation unit 140 may notify the user by, for example, displaying the newly set speed of the motor 37 on the display device 30.

[0034] The measuring device 1 according to the present embodiment having the above configuration determines whether the coordinate value of the position where the shape of the workpiece has changed can be accurately calculated, and if it cannot be accurately calculated, changes the speed of the motor based on the measurement information so that the coordinate value of the position where the shape of the workpiece has changed can be accurately calculated. As a result, it becomes possible to use the correct measurement result of the workpiece.

[0035] [Correction based on Rule 91, 29.10.2024] The measuring device 1 according to each of the embodiments described above determines whether the coordinate value of the position where the shape of the workpiece has changed can be accurately calculated, and if it cannot be accurately calculated, notifies the user to that effect. The user who has received the notification can adjust the relative speed between the workpiece and the measuring instrument and then measure the shape of the workpiece again. As a result, it becomes possible to use the correct measurement result of the workpiece.

[0036] In the above, an example of measuring the shape of the teeth of a gear as the measurement object has been shown. However, for example, as illustrated in FIG. 7, it can also be used when measuring the surface shape of a workpiece other than a gear. In the example of FIG. 7, the measuring instrument 35 is arranged on the measurement surface of the workpiece placed on the table. Then, by driving the motor 37 to move the table, the measuring instrument 35 is scanned along the surface of the workpiece. Even in such a case, by using the measuring device 1 according to the present disclosure, it is possible to determine whether the moving speed of the table is incorrect and notify the user. The measuring device 1 of the present disclosure can be effectively utilized in the same manner when the measuring instrument 35 is gripped by a robot or the like and scanned on the measurement surface of the workpiece.

[0037] Although the present disclosure has been described in detail above, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of the present disclosure or from the spirit of the present disclosure derived from the claims and their equivalents. Furthermore, these embodiments can be implemented in combination. For example, the order of operations and processes in the embodiments described above are shown as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0038] With respect to the above embodiments and modifications, the following additional notes are disclosed. (Addendum 1) The measuring device comprises: a coordinate value calculation unit that calculates the coordinate values ​​of the position where the shape of the measuring surface has changed based on a signal input from a measuring instrument that moves its relative position to the measuring surface of the object to be measured and measures the change in the shape of the measuring surface; a measurement information recording unit that records measurement information relating to the time interval in which a shape change occurs on the measuring surface of the object to be measured; and a speed inaccuracy determination unit that determines that the relative speed between the measuring surface of the object to be measured and the measuring instrument is incorrect if the time interval in which a shape change occurs on the measuring surface of the object to be measured, as recorded by the measurement information recording unit, is shorter than a predetermined first threshold; and when the speed inaccuracy determination unit determines that the relative speed between the measuring surface of the object to be measured and the measuring instrument is incorrect, it notifies that the measuring surface of the object to be measured has not been evaluated correctly.

[0039] (Note 2) The measurement information recording unit does not record measurement information related to the time interval during which a shape change occurs on the measurement surface of the object being measured if the time interval is shorter than a predetermined second threshold.

[0040] (Note 3) The measuring device further includes a motor speed calculation unit that, when the speed fraud determination unit determines that the relative speed between the measuring surface of the object to be measured and the measuring instrument is fraudulent, calculates the speed of a motor that moves the measuring surface of the object to be measured and the measuring instrument relative to each other, based on the measurement information and the first threshold value.

[0041] (Note 4) The measuring device changes the speed of the motor to the speed of the motor calculated by the motor speed calculation unit.

[0042] The measuring device according to claim 1, wherein the speed fraud determination unit determines that the relative speed between the measuring surface of the object to be measured and the measuring instrument is fraudulent, and notifies an alarm.

[0043] 1 Measuring device 11 CPU 12 ROM 13 RAM 14 Non-volatile memory 15, 18, 19, 20, 21 Interface 22 Bus 30 Display device 31 Input device 32 External device 35 Measuring instrument 37 Motor 110 Coordinate value calculation unit 120 Measurement information recording unit 130 Speed ​​error detection unit 140 Motor speed calculation unit

Claims

1. A measuring device comprising: a coordinate value calculation unit that calculates the coordinate values ​​of the position where the shape of the measuring surface has changed based on a signal input from a measuring instrument that moves its relative position to the measuring surface of the object to be measured and measures the change in the shape of the measuring surface; a measurement information recording unit that records measurement information relating to the time interval at which a shape change occurs on the measuring surface of the object to be measured; and a speed error determination unit that determines that the relative speed between the measuring surface of the object to be measured and the measuring instrument is incorrect if the time interval at which a shape change occurs on the measuring surface of the object to be measured, as recorded by the measurement information recording unit, is shorter than a predetermined first threshold, wherein the speed error determination unit notifies that the measuring surface of the object to be measured has not been evaluated correctly.

2. The measuring device according to claim 1, wherein the measurement information recording unit does not record measurement information related to a time interval if the time interval in which a shape change occurs on the measuring surface of the object to be measured is shorter than a predetermined second threshold.

3. The measuring device according to claim 1, further comprising a motor speed calculation unit that, when the speed fraud determination unit determines that the relative speed between the measuring surface of the object to be measured and the measuring instrument is fraudulent, calculates the speed of a motor that moves the measuring surface of the object to be measured and the measuring instrument relative to each other, based on the measurement information and the first threshold value.

4. The measuring device according to claim 3, which changes the speed of the motor to the speed of the motor calculated by the motor speed calculation unit.

5. The measuring device according to claim 1, wherein the speed fraud determination unit determines that the relative speed between the measuring surface of the object to be measured and the measuring instrument is fraudulent, and notifies the user as an alarm.

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