Form measuring device and computer-readable storage medium

Abstract

This shape measuring device: obtains the height of a surface of a measuring object from a distance sensor that moves relative to the surface of the measuring object; calculates coordinate values ​​of a rising portion or falling portion present on the surface of the measuring object; stores reference values ​​for the coordinate values ​​of the rising portion or falling portion; compares the reference values ​​with the coordinate values ​​calculated by a coordinate value calculation unit; determines coordinate values ​​different from the reference values ​​as invalid data; changes speed conditions for the relative speed between the measuring object and the distance sensor; and determines a factor of the invalid data by performing comparisons with coordinate values ​​calculated according to different speed conditions.

Description

Technical FieldThe present invention relates to a shape measuring device and a computer readable storage medium.Related ArtThere are conventional shape measuring devices that irradiate a measurement object with measurement light to measure a position of each part of the measurement object. For example, such a device is described in Patent Literature 1.Prior Art DocumentPatent Literature[Patent Literature 1] Japanese Patent Application Laid-Open No. 2014-137265Summary of the InventionProblems to be Solved by the InventionSome shape measuring devices are configured to store reference values for rising and falling edges of a signal and compare the reference values with measurement results to determine the accuracy of the shape of a measurement object. In the shape measurement, incorrect detection can occur.In the field of shape measurement devices, a technology for determining the factors for false detection is desired.Means for Solving the ProblemAn aspect of the present disclosure is a shape measurement device including: a coordinate value calculation unit that acquires a height of a surface of a measurement object from a distance sensor that moves relative to the surface of the measurement object and calculates coordinate values of a rising edge or a falling edge present on the surface of the measurement object based on the height; a reference value storage unit that stores reference values of the coordinate values of the rising edge or the falling edge; a data comparison unit that compares the reference values with the coordinate values calculated by the coordinate value calculation unit; and a factor determination unit that determines coordinate values different from the reference values as incorrect data, changes a speed condition of a relative speed between the measurement object and the distance sensor, and performs comparison of coordinate values calculated at a different speed condition, thereby determining a factor that causes the incorrect data.Brief Description of the DrawingsThe following are shown: FIG. 1 is a block diagram of a shape measuring apparatus; FIG. 2 shows a schematic illustration of a shape measuring device for measuring a linear measurement object; FIG. 3 is a schematic illustration of a shape measuring device for measuring a circular measurement object; FIG. 4 is a schematic illustration of linear coordinate values; FIG. 5 is a schematic illustration of circular coordinate values; FIG. 6 is a schematic illustration of changes in coordinate values; FIG. 7 shows a schematic illustration of the coordinate values when chatter occurs; FIG. 8 is a schematic illustration of changes in coordinate values; FIG. 9 is a flowchart describing the operation of the shape measuring apparatus; and FIG. 10 is a hardware configuration diagram of the shape measurement device.DETAILED DESCRIPTION(First Embodiment)A shape measuring apparatus 100 according to a first embodiment will be described below. The shape measuring device 100 is applied to a machine such as a gear measuring instrument for measuring uneven portions of a measurement object. The shape measuring device 100 can be applied to a control device such as a numerical control device, other devices, and an information processing device such as a personal computer (PC). The constituent elements of the shape measuring device 100 differ depending on the devices to which the measuring device 100 is applied.The components of the shape measuring device can be categorized according to their functions and need not be clearly distinguishable in their physical and programmatic configuration.FIG. 1 is a block diagram of the shape measuring apparatus 100. The shape measuring apparatus 100 includes a motor driving unit 11, a motor control unit 12, a distance sensor 13, a coordinate value calculation unit 14, a reference value storage unit 15, a data comparison unit 16, a factor determination unit 17, and a factor notification unit 18.The motor drive unit 11 is configured to drive a motor according to the commands from the motor control unit 12. The motor is equipped with a sensor, which is not shown. The encoder outputs a rotation angle of the motor.The motor control unit 12 is configured to acquire the rotation angle of the motor to control a rotation speed (rotation angle) of the motor in turn. A method for controlling the motor is different between a linear measurement object (workpiece) and a circular measurement object.In the case of the linear measurement object, a rotational motion of the motor is converted into a linear motion by a ball screw as illustrated in FIG. 2. The motor control unit 12 controls a relative position of the distance sensor 13 and the measurement object (a table on which the measurement object is mounted).In the case of the circular measurement object, the motor rotates the circular measurement object as illustrated in FIG. 3. The motor control unit 12 controls the rotation speed (rotation angle) of the motor obtained from the encoder.The distance sensor 13 is configured to irradiate the measurement object with an acoustic wave, light, and the like to detect the height of the surface of the measurement object corresponding to the reflection of the measurement object.The coordinate value calculation unit 14 is configured to calculate the coordinate values of the rising and falling edges of asperities on the surface of the measurement object on the basis of the height of the surface of the measurement object detected by the distance sensor 13. The coordinate values are calculated using the existing technique.The units of the coordinate values are different between the linear measurement object and the circular measurement object.In the case of the linear measurement object, the coordinate values are the position of the distance sensor with respect to the measurement object.In the case of the circular measurement object, the coordinate values are the angles of the motor.The reference value storage unit 15 is configured to store reference coordinate values. The reference coordinate values indicate the positions of the rising and falling edges on the surface of the measurement object. The cross section of the linear measurement object has a rectangular shape in the exemplary embodiment for the purpose of illustration, but can also have a different shape, e.g. trapezoidal.The reference values include a machine coordinate of a machine that measures the measurement object, a relative coordinate to an origin set on the machine coordinate, a coordinate distance (or an angle difference), and the like.The machine coordinate is unique to the machine. The relative coordinate has an arbitrary point on the machine coordinate as a starting point. The coordinate distance is a distance between two or more reference values on the machine coordinate.When the measurement object is circular, a single point on a rotation axis is set as an origin. The relative coordinate has an arbitrary point on the rotation axis as a starting point. The distance between the coordinates is a distance between two or more reference values on the rotation axis.The reference value may be calculated from an ideal original shape of the measurement object, a blue pause of the measurement object, and the like. For example, the ideal original shape of the measurement object is measured, and the coordinate values of the rising and falling edges in the original shape are used as reference values. The reference values of the rising and falling edges can be calculated from the blue pause. Tolerances can be set as reference values. When the tolerances are set, the factor determination unit 17 determines that coordinate values exceeding the tolerances are deemed to be incorrect data.The data comparing unit 16 is configured to compare the coordinate values of the rising edge and the falling edge calculated by the coordinate value calculating unit 14 with the reference values stored in the reference value storage unit 15. If the coordinate values of the rising and falling edges deviate from the reference values according to the comparison result, the data concerned is determined as incorrect data.When the data comparing unit 16 detects the incorrect data, the factor determining unit 17 sends a command to the motor control unit 12 to change a speed condition of the motor, thereby performing re-measurement of the coordinate values.When coordinate values that match the previous coordinate values are detected due to the change in the speed condition of the motor, the factor determination unit 17 determines that the factor that causes the incorrect data is the defective shape of the measurement object. When coordinate values deviating from the previous coordinate values are detected due to the change in the speed condition of the motor, the factor determination unit 17 determines that the factor causing the incorrect data is the chatter. When incorrect data is not detected due to the change in the speed condition of the motor, the factor determination unit 17 determines that the factor causing the incorrect data is noise or the speed condition.The factor notification unit 18 is configured to notify a user of the determination result to which the factor determination unit 17 arrives. The notification may be made according to a conventional method.Next, the shape measuring device 100 will be described using the example of a linear measurement object. FIG. 4 is a schematic diagram of the shape measuring apparatus 100 for measuring the linear measurement object. The distance sensor 13 measures the height of the surface of the measurement object while moving parallel to the measurement object.The shape measuring device 100 acquires the coordinate values of the positions of the rising edge and the falling edge on the surface of the measurement object on the basis of the height of the surface of the measurement object acquired by the distance sensor 13. The reference value storage unit 15 stores the reference values of the coordinate values of the rising edge and the falling edge. In FIG. 4, as reference values for the coordinate values, the coordinate values with the measurement start position of the distance sensor 13 as the origin and the reference value of the distance between the coordinates of the two points are drawn.The reference values with the measurement start position of the distance sensor 13 as the origin are "3, 6, 9... " for the rising edge and "4, 7, 10... " for the falling edge. The reference values of the distances between the coordinates are the distances "1, 2, 1, 2, 1, 3,... " between the rising edge and the falling edge. The reference values for the distances between the coordinates may be a slot "all 1".The data comparison unit 16 compares the reference values with the coordinate values (actual measurement values) detected by the distance sensor. The actual measured values here are "3, 4, 6, 7, 9, 10, 1... ". The data comparing unit 16 determines that the coordinate value "10,1" other than the reference value at the third falling edge is incorrect data.The factor determination unit 17 changes the speed condition of the motor when the incorrect data is detected, and starts re-measurement. The factor determination unit 17 sends a command to the engine control unit 12.The factor determination unit 17 compares the coordinate values of the rising edge and the falling edge acquired in the new speed condition with the coordinate values of the rising edge and the falling edge acquired in the previous speed condition. When a coordinate value in the incorrect data acquired in the new speed condition deviates from the coordinate value "10,1" of the incorrect data acquired previously, the factor determination unit 17 determines that the factor causing the incorrect data is chatter.When the coordinate value in the incorrect data acquired in the new speed condition matches the coordinate value "10,1" of the incorrect data acquired previously, the factor determination unit 17 determines that there is an erroneous shape in the position of the coordinate value "10,1.".When the incorrect data acquired previously is not acquired in the new speed condition, the factor determination unit 17 determines that the factor causing the incorrect data is noise or the speed condition.Next, an example of measurement of a circular measurement object will be described. FIG. 5 is a schematic diagram of the shape measuring device 100 that measures the circular measurement object. The distance sensor 13 irradiates the surface of the measurement object with, for example, a laser. The measurement object is rotated to allow the laser to measure the height of the surface of the measurement object. The measurement object in FIG. 5 has a missing portion in the position at "95°".The reference value storage unit 15 stores the reference values for the coordinate values of the rising edge and the falling edge. The schematic diagram in FIG. 5 shows, as reference values for the coordinate values, reference values having a single point on a rotation axis as an origin and a distance between the coordinates of two points on the rotation axis. The reference values having a single point on the rotation axis as the origin are coordinate values of the rising edge "0, 45, 90, 135... " and coordinate values of the falling edge "15, 60, 105, 150... ". The reference values of the distances between the coordinates may be expressed by, for example, "tooth tip: 15, tooth space: 30", or angles between the rising and falling flanks "15, 30, 15, 30, 15... ".For example, when the measurement object is rotated at a certain speed, the distance sensor 13 detects the coordinate values of the rising edge "0, 45, 90, 100, 135... " and the coordinate values of the falling edge "15, 60, 95, 105, 150... ".The coordinate value detected by the distance sensor 13 can be expressed by an angle difference between two points (tooth tip: 15, 5, tooth space: 30, 5).The factor determination unit 17 compares the reference values with the coordinate values detected by the distance sensor 13. The fourth coordinate value of the rising edge "100" and the third coordinate value of the falling edge "95" are different from the reference values. The factor determination unit 17 determines that the coordinate values "100" and "95" different from the reference values are incorrect data.The factor determination unit 17 changes the speed condition of the motor in response to the detection of the incorrect data. The measurement object is then rotated at a new speed to be remeasured at the new speed condition.With reference to FIGS. 5 and 6, a process for determining that a missing portion is a factor causing the incorrect data will be described.The distance sensor 13 irradiates the surface of the measurement object with a laser. The measurement object is rotated to allow the laser to measure the height of the surface of the measurement object. The measurement object in FIG. 5 has a missing portion at the position "95°".The shape measuring device 100 rotates the measurement object at a normal speed. At this time, the data comparing unit 16 compares the reference values with the coordinate values detected by the distance sensor 13, and determines that the third coordinate value "95" of the falling edge is incorrect data. The factor determination unit 17 changes the speed condition of the motor when the incorrect data is detected.FIG. 6 is a schematic diagram showing a change in the coordinate values when the speed condition of the measurement object is changed.In this example, engine speed is reduced. In a case where the coordinate values of the incorrect data are not changed even when the speed condition of the motor is changed, the factor determination unit 17 determines that a missing portion is present at the position of the coordinate value at which the incorrect data occurs.With reference to FIGS. 7 and 8, a process for determining that the chatter is a factor causing the incorrect data will be described.In the shape measuring apparatus 100 in FIG. 7, the chatter occurs in the distance sensor 13.The distance sensor 13 irradiates the surface of the measurement object with a laser. The measurement object is rotated to allow the laser to measure the height of the surface of the measurement object.When the measurement object is rotated at a certain speed, the distance sensor 13 acquires the coordinate values of the rising edge "0, 0, 0, 4, 45, 45, 45, 4, 90, 90,4... " and the coordinate values of the falling edge "0, 2, 15, 45, 2, 60, 90, 2, 105... ".The distance sensor 13 can detect an angle difference between two points as coordinate values (tooth tip: 15, 0.2, tooth space: 30, 0.2).The factor determination unit 17 compares the reference values with the coordinate values detected by the distance sensor. In the example illustrated in FIG. 7, the second rising edge coordinate value "0,4", the fourth rising edge coordinate value "45,4", the sixth rising edge coordinate value "90,4", the first falling edge coordinate value "0,2", the third falling edge coordinate value "45,2", and the fifth falling edge coordinate value "90,2" are different from the reference values.The factor determination unit 17 determines these coordinate values "0,2", "0,4", "45,2", "45,4", "90,2", and "90,4" as incorrect data.The factor determination unit 17 changes the speed condition of the motor in response to the detection of the incorrect data. In the case of the circular measurement object, the measurement can be performed again by changing the speed condition.FIG. 8 shows the change of the coordinate values when the speed condition of the measurement object is changed.It is assumed that the incorrect data is acquired in the value of the first falling edge "0.2" and in the value of the second rising edge "0.4", when the measurement object is rotated at a certain speed. The factor determination unit 17 changes the speed condition of the motor in response to the detection of the incorrect data. In this example, engine speed is reduced. When the engine speed is 0.2° / ms for a chatter signal of 1 ms, the incorrect data is generated at the coordinate values "0.2" and "0.4". When the engine speed is changed to 0.1° / ms, the incorrect data is generated at the coordinate values "0.1" and "0.2".The factor determination unit 17 changes the speed condition of the motor and, when the coordinate values of the incorrect data are changed, determines that the chatter is the factor causing the incorrect data.When the incorrect data of the coordinate values "0.2" and "0.4" are no longer detected due to the change of the speed condition, the factor determination unit 17 determines that the noise or the speed condition is the factor causing the incorrect data.Next, the operation of the shape measuring apparatus 100 will be described with reference to a flowchart in FIG. 9. The shape measuring apparatus 100 rotates the motor at a certain speed (step S 1). The rotation of the motor allows the surface of the measurement object and the distance sensor 13 to move relative to each other. The surface of the measurement object and the distance sensor 13 are moved relative to each other, so that the coordinate value of the position detected by the distance sensor 13 is changed. The distance sensor 13 measures the height of the surface of the measurement object (step S 2).The shape measuring device 100 calculates the coordinate values of the rising and falling edges of the surface of the measurement object (step S 3). The shape measuring device 100 compares the calculated coordinate values with the reference values (step S 4).When the detected coordinate values coincide with the reference values (step S 5: equal), the measurement is determined to be normal (step S 6), and the process of factor determination is ended. When the coordinate values are different from the reference values (step S 5: different), the shape measurement device 100 determines the coordinate values acquired in step S 3 as incorrect data (step S 7).When the incorrect data is acquired in step S 7, the shape measuring device 100 changes the speed condition of the motor (step S 8). The shape measuring device 100 changes the motor rotation speed and calculates coordinate values (step S 9). Then, the shape measuring device 100 compares the coordinate values of the incorrect data calculated on the new speed condition with the coordinate values of the incorrect data acquired beforehand (step S 10). When the coordinate values of the incorrect data acquired in the new speed condition match the coordinate values of the incorrect data acquired previously (step S 11: equal), the shape measuring device 100 determines that the shape of the measurement object is the factor causing the incorrect data (step S 12), and ends the factor determination process.When the coordinate values of the incorrect data acquired in the new speed condition are different from the coordinate values of the incorrect data acquired previously (step S 11: different), the shape measurement device 100 determines that the chatter is the factor causing the incorrect data (step S 13).When incorrect data is not detected, the shape measuring apparatus 100 determines that the incorrect data is caused by another factor such as noise or the speed condition by changing the speed conditions again (step S 11: not detected).As described above, the shape measuring apparatus 100 of the embodiment changes the engine rotation speed in response to the detection of the incorrect data having values different from the reference values to perform the re-measurement. In a case where the change in the engine speed does not cause the change in the coordinate values at the position where the incorrect data is generated, it is determined that there is an error in the shape such as a missing portion at the position where the incorrect data is generated.When the coordinate values change at the location where the incorrect data is generated, the shape measuring device 100 determines that the chatter has occurred. The chatter changes depending on the engine speed.When the result of the re-measurement shows that incorrect data is not generated, the shape measuring apparatus 100 determines that another factor, e.g., noise or the speed condition, causes the generation of the incorrect data.According to the shape measuring apparatus 100 of the present disclosure, since the factor causing the incorrect data can be evaluated, the measurement accuracy can be increased. Moreover, the factor causing the incorrect data is automatically determined, so that the measurement frequency and measurement time can be reduced.A hardware configuration of the shape measurement device 100 to which the present disclosure is applied will be described below. FIG. 10 is a hardware configuration diagram of the shape measurement device 100. As illustrated in FIG. 10, the shape measuring apparatus 100 includes a central processing unit (CPU) 111 configured to fully control the shape measuring apparatus 100, a read-only memory (ROM) 112 configured to store programs and data, and a random access memory (RAM) 113 into which the data is temporarily loaded. The CPU 111 reads a system program stored in the ROM 112 via a bus and executes a shape measurement process according to the system program.A nonvolatile memory 114 is buffered by, for example, a battery not illustrated, so that the storage conditions can be maintained even when a power source of the shape measuring apparatus 100 is turned off. The nonvolatile memory 114 is configured to store programs read from an external device 120 via the interfaces 115, 118, and 119, as well as various data on user operations and others input via an input unit 30. The nonvolatile memory 114 may store programs and data for execution of the shape measurement device 100 of the illustrated embodiment. Moreover, a display unit 70 is configured to display the various data, measurement results, incorrect data factors, and the like.The interface 115 is configured to connect the shape measurement device 100 to the external device 120, e.g., an adapter. Programs, various parameters, and the like are read from the external device 120.The interface 118 is configured to connect the shape measuring device 100 to the display unit 70, for example, a liquid crystal display. The display unit 70 displays, for example, the data loaded in the memory and the data obtained as a result of the execution of the programs.The interface 119 is configured to connect the shape measurement device 100 to the input unit 30, e.g., a keyboard or a pointing device. The input unit 30 transmits commands, data, and the like generated due to the operation by an operator to the CPU 111 via the interface 119.The present disclosure has been described in detail, but is not limited to the above-described embodiments. Thus, various additions, substitutions, modifications, division strokes, etc. can be made to these embodiments without departing from the spirit or spirit of the disclosure as set forth in the contents described in the claims and their equivalents. Moreover, these embodiments can also be realized by combinations. For example, the order of the operations and the order of the processes in these embodiments are exemplary and therefore not limited.With respect to the above-described embodiments and their variations, supplementary remarks will be made below.(Supplementary Note 1)A shape measuring device (100) includes a coordinate value calculation unit (14) that acquires a height of a surface of a measurement object from a distance sensor (13) that moves relative to the surface of the measurement object and calculates coordinate values of a rising edge or a falling edge present on the surface of the measurement object based on the height, a reference value storage unit (15) that stores reference values for the coordinate values of the rising edge or the falling edge, a data comparison unit (16) that compares the reference values with the coordinate values calculated by the coordinate value calculation unit, and a factor determination unit (17) that determines coordinate values other than the reference values as incorrect data, changes a speed condition of a relative speed between the measurement object and the distance sensor, and performs comparison of coordinate values, calculated at another speed condition to thereby determine a factor causing the incorrect data.(Supplementary Note 2)When the coordinate values calculated for the different speed conditions are equal, the factor determination unit ( 17) determines that the factor causing the incorrect data is the shape of the measurement object.(Supplementary Note 3)When the coordinate values calculated for the different speed conditions are different, the factor determination unit ( 17) determines that the factor causing the incorrect data is the chatter in the distance sensor.(Supplementary Note 4)When incorrect data is not detected as a result of the change in the speed condition, the factor determination unit (17) determines that the factor causing the incorrect data is noise or the speed condition.(Supplementary Note 5)The coordinate values in the shape measuring device ( 100) are at least one / n of a machine coordinate, a coordinate relative to an arbitrary reference point, and a distance between the coordinates of at least two or more points.(Supplementary Note 6)The reference values for the coordinate values in the shape measuring device ( 100) are calculated from at least one of an ideal original shape of the measurement object and a blue pause of the measurement object.(Supplementary Note 7)The shape measuring device (100) includes a notification unit that notifies a user of the factor causing the incorrect data.(Supplementary Note 8)A storage medium (112, 113, 114) storing instructions readable by one or more processors (111), the instructions being executed by the one or more processors (111) to acquire a height of a surface of a measurement object from a distance sensor (13) that moves relative to the surface of the measurement object, to calculate coordinate values of a rising edge or a falling edge present on the surface of the measurement object based on the height, to compare reference values for the coordinate values of the rising edge or the falling edge with the coordinate values of the rising edge or the falling edge present on the surface of the measurement object, to determine coordinate values different from the reference values as incorrect data, changing a speed condition of a relative speed between the measurement object and the distance sensor to perform comparison of coordinate values calculated at another speed condition, thereby determining a factor causing the incorrect data.List of reference characters100 Shape measuring device 13 Distance sensor 14 Coordinate value calculating unit 15 Reference value storage unit 16 Data comparing unit 17 Factor determining unit 18 Factor notifying unit 111 CPU 112 ROM 113 RAM 114 Nonvolatile memoryReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2014-137265

[0003]

Claims

A shape measurement device, comprising: a coordinate value calculation unit that acquires a height of a surface of a measurement object from a distance sensor that moves relative to the surface of the measurement object and calculates rising edge or falling edge coordinate values present on the surface of the measurement object based on the height; a reference value storage unit that stores reference values of the coordinate values of the rising edge or falling edge; a data comparison unit that compares the reference values with the coordinate values calculated by the coordinate value calculation unit; and a factor determination unit that determines coordinate values different from the reference values as incorrect data, changes a speed condition of a relative speed between the measurement object and the distance sensor, and performs comparison of coordinate values calculated at another speed condition, thereby determining a factor that causes the incorrect data.The shape measuring apparatus according to claim 1, wherein the factor determination unit determines that a factor causing the incorrect data is the shape of the measurement object when the coordinate values calculated for the different speed conditions are the same.The shape measuring apparatus according to claim 1, wherein the factor determination unit determines that a factor causing the incorrect data is the chatter in the distance sensor when the coordinate values calculated for the different speed conditions are different.The shape measuring apparatus according to claim 1, wherein when incorrect data is not detected as a result of the change in the speed condition, the determination unit determines that the factor causing the incorrect data is noise or the speed condition.The shape measuring apparatus according to claim 1, wherein the coordinate values are at least one / n of a machine coordinate, a coordinate relative to an arbitrary reference point, and a distance between the coordinates of at least two or more points.The shape measuring apparatus according to claim 1, wherein the reference values for the coordinate values are calculated from at least one of an ideal original shape of the measurement object and a blue-blank of the measurement object.The shape measuring apparatus according to claim 1, comprising a notifying unit that notifies a user of the factor causing the incorrect data.A storage medium storing instructions readable by one or more processors, the instructions executed by the one or more processors to: acquire a height of a surface of a measurement object from a distance sensor that moves relative to the surface of the measurement object to calculate, based on the height, coordinate values of a rising edge or falling edge present on the surface of the measurement object; compare reference values for the coordinate values of the rising edge or the falling edge with the coordinate values of the rising edge or the falling edge present on the surface of the measurement object; and determining coordinate values different from the reference values as incorrect data, changing a speed condition of a relative speed between the measurement object and the distance sensor, and performing comparison of coordinate values calculated under another speed condition, thereby determining a factor causing the incorrect data.

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