Machine apparatus and optical distance measuring method

Abstract

This machine apparatus is provided with: a processing machine (100) that is capable of five-axis drive and provided with a processing head; an optical sensor (111) that is provided with a sensor head and an optical sensor body and measures the distance to an object; and a controller (200) that controls the drive of the processing machine and measures the three-dimensional shape of the object on the basis of the distance measurement information, wherein the sensor head can be attached to the processing head, and the controller has a coordinate setting unit (221) that sets processing head coordinates, a film thickness map creation unit (224) that detects a liquid on the object and creates a film thickness map of the liquid on the basis of the distance information measured by the optical sensor by moving the object around the rotation axis, and a three-dimensional shape measurement unit (226) that generates a three-dimensional map of the object by combining the distance measurement data of the object obtained at the rotation angles at which the thickness data used for creating the film thickness map have been acquired.

Description

Machining device and optical distance measuring method

[0001] The present disclosure relates to optical distance measurement technology, and more particularly to a machining device equipped with an optical sensor and an optical distance measurement method.

[0002] Patent Document 1 discloses a method for measuring the shape of an object to be measured that has a film of water or oil or the like attached thereto, based on distance measurement results obtained from an imaged light-dark pattern, using multiple laser beams and a CCD camera.

[0003] Japanese Patent Application Laid-Open No. 2019-060647

[0004] The technology of Patent Document 1 is premised on a triangulation method using a CCD camera as a distance measurement method, which has the problem of limiting the shape measurement of the measurement object. For example, the triangulation method cannot measure the edge of a film, so the shape measurement of the measurement object in the area where the edge of the film overlaps with the measurement object is limited. In addition, the measurement range is limited depending on the length of the CCD element.

[0005] The present disclosure has been made to solve such problems, and aims to provide an optical ranging technology that enables measurement of the shape of an object even when liquid such as water or oil is attached to the object.

[0006] One aspect of a machining device according to an embodiment of the present disclosure includes a processing machine having a processing head for processing an object, the processing machine being drivable along three mutually perpendicular linear axes and drivable around two rotational axes; an optical sensor having a sensor head and an optical sensor main body and capable of measuring the distance to the object; and a controller that controls the operation of the processing machine and measures the three-dimensional shape of the object based on distance measurement information of the optical sensor, wherein the sensor head of the optical sensor is attachable to the processing head of the processing machine, and the controller includes: a coordinate setting unit that sets coordinates of the processing head of the processing machine; a film thickness map creation unit that detects liquid present on the object based on the coordinates set by the coordinate setting unit and distance information measured by the optical sensor by driving the object around the rotational axis to move the object relatively, and creates a film thickness map that combines multiple position data indicating the location of the liquid present on the object and multiple thickness data indicating the thickness of the liquid; and a three-dimensional shape measurement unit that generates a three-dimensional map of the object by combining distance measurement data of the object obtained at the rotational angle at which each thickness data used to create the film thickness map was acquired.

[0007] According to the machining device according to the embodiment of the present disclosure, it is possible to measure the shape of an object even when a liquid such as water or oil is attached to the object.

[0008] FIG. 1 is a diagram illustrating an example of the configuration of a machining device. FIG. 2 is a flowchart illustrating the operation of the machining device. FIG. 3 is a table describing variables. FIG. 4A is a schematic diagram of a film thickness map, and FIG. 4B is a diagram illustrating the presence of a film in real space corresponding to the film thickness map. FIG. 4B is a diagram illustrating the relationship between stroke length, sensor head length, and B coordinate. FIG. 5 is a diagram illustrating a method for creating a film thickness map. FIG. 6A is a diagram illustrating basic data used to create a film thickness map. FIG. 6B is a diagram illustrating a portion of a created film thickness map. FIG. 6B is a diagram illustrating basic data used to create a distance measurement map. FIG. 9A is a schematic diagram showing an object with an oil film attached. FIG. 9B is ground truth data showing the shape of the object. FIG. 10A is a diagram illustrating distance measurement data of an object measured when the B coordinate is 90 degrees. FIG. 10B is a diagram illustrating distance measurement data of an object measured when the B coordinate is 80 degrees. FIG. 10C is a diagram illustrating distance measurement data of an object measured when the B coordinate is 70 degrees. FIG. 10D is a diagram showing a distance measurement map created by combining R1 in FIG. 10A, R2 in FIG. 10A, and R3 in FIG. 10C.

[0009] Various embodiments of the present disclosure will be described in detail below with reference to the drawings. In the drawings, identical or similar parts are designated by identical or similar reference numerals, and redundant explanations of such parts will be omitted. In addition, in this disclosure, the term "or" is used to mean an inclusive logical OR unless otherwise specified.

[0010] Embodiment 1. <Configuration> A machining device according to embodiment 1 of the present disclosure will be described with reference to FIG. 1 . This is a diagram illustrating an example configuration of the machining device. As illustrated in FIG. 1 , the machining device includes a processing machine 100, an optical sensor 111, and a controller 200. As an example, the optical sensor 111 includes an optical sensor body and a sensor head, and the entire optical sensor 111 is mounted on the processing machine 100. As another example, the sensor head of the optical sensor 111 may be mounted on the processing machine 100, and the sensor body of the optical sensor 111 may be located on the controller 200 or in another location. The processing machine 100 is a processing machine capable of five-axis machining and processes a workpiece under the control of the controller 200. Based on reflected light acquired from the sensor head of the optical sensor 111, the sensor body of the optical sensor 111 performs signal processing to measure the distance to the workpiece, and the sensor body of the optical sensor 111 supplies the distance measurement information to the controller 200.

[0011] (Processing machine) The processing machine 100 includes a processing unit 120 that performs machining, a tool magazine 110 that stores a plurality of processing tools for performing the machining, and a tool magazine displacement means 125 that acquires the processing tools and attaches the acquired processing tools to the processing head 122.

[0012] (Processing Unit) The processing unit 120 includes a processing head displacement means 121 that displaces the processing head 122, a stage 124 on which the workpiece is placed, and a cutting oil nozzle 123 that supplies cutting oil used when processing the workpiece. One of the processing tools T0 to T3 is attached to the processing head 122 by a tool magazine displacement means 125. The processing head displacement means 121 is a displacement means capable of five-axis processing and is configured to be capable of displacement along a linear axis or a rotational axis. The linear axes include the X-axis, Y-axis, and Z-axis, which are orthogonal to each other. The rotational axes include, for example, the B-axis around the Y-axis and the C-axis around the Z-axis. The processing head displacement means 121 is configured, for example, with five motors.

[0013] When measuring the distance, the optical sensor 111 is selected by the tool magazine selection unit 223, and the sensor head of the optical sensor 111 is attached to the machining head 122. Therefore, by moving the machining head 122 along the X-axis, Y-axis, or Z-axis, or around the B-axis or C-axis, the optical sensor 111 can measure the distance to the object to be measured. For example, by fixing the X-coordinate, Y-coordinate, Z-coordinate, and C-coordinate, and moving the machining head 122 around the B-axis, the optical sensor 111 can perform measurements while changing the B-coordinate.

[0014] (Tool Magazine) The tool magazine 110 stores a plurality of machining tools T0 to T3. A tool magazine displacement means 125 acquires one of the machining tools T0 to T3 stored in the tool magazine 110, and the machining tool acquired by the tool magazine displacement means 125 is attached to the machining head 122. The tool magazine displacement means 125 is formed, for example, by a motor.

[0015] (Optical Sensor) The optical sensor 111 is a sensor that performs optical distance measurement using the FMCW (Frequency Modulated Continuous Wave) method. The optical sensor 111 includes an optical sensor body and a sensor head (see FIG. 5). During distance measurement, the sensor head of the optical sensor 111 is attached to the processing head 122. The optical sensor body and the sensor head are connected by an optical fiber, allowing measurement light or reflected light to propagate through the optical fiber.

[0016] The optical sensor body is a known optical sensor, and includes a frequency swept light output unit that outputs frequency swept frequency light, a coupler that splits the frequency swept light into reference light and measurement light, a circulator that guides the measurement light to the sensor head and guides the reflected light to an optical interferometer, an optical interferometer that causes interference between the reference light and the reflected light, a photodetector that detects the interference light, an A / D converter that samples the detected interference light and converts it into an electrical signal, and a signal processing device that processes the electrical signal to calculate the distance to the object to be measured.If a film of cutting oil or the like is attached to the object to be measured, it is possible to measure the distance to the surface of the film in addition to the distance to the object surface.

[0017] The sensor head includes an optical system including a lens that irradiates the measurement light, which propagates from the circulator through the optical fiber, onto the object and receives the reflected light from the object to be measured.

[0018] The optical sensor 111 outputs the distance measurement result to the controller 200 as distance measurement information.

[0019] (Controller) The controller 200 includes an input device 210 , a processor 220 , a memory 230 , and a display device 240 .

[0020] (Input Device) The input device 210 is a device for inputting values ​​related to processing conditions or measurement conditions for the object to be processed. The input device 210 is, for example, a keyboard or a touch panel.

[0021] (Processor) The processor 220 includes, as functional units, a coordinate setting unit 221, a cutting oil supply control unit 222, a tool magazine selection unit 223, a film thickness map creation unit 224, a three-dimensional shape measurement unit 226, and a determination unit 227. These functional units are realized by the processor 220 reading out a program stored in a memory and executing the read program.

[0022] (Coordinate Setting Unit) The coordinate setting unit 221 sets the coordinates of the processing head 122 and outputs the set coordinates to the processing head displacement means 121 and the film thickness map creation unit 224. The set coordinates include an X coordinate, a Y coordinate, a Z coordinate, as well as a B coordinate and a C coordinate.

[0023] (Cutting Oil Supply Control Unit) The cutting oil supply control unit 222 is a functional unit that controls the supply of cutting oil from the cutting oil nozzle 123 .

[0024] (Tool magazine selection unit) The tool magazine selection unit 223 is a functional unit that selects the machining tool or sensor head to be used from among the machining tools T0 to T3 and the sensor head of the optical sensor 111, and supplies information indicating the selected object to the tool magazine displacement means 125 as tool information.

[0025] (Film Thickness Map Creation Unit) The film thickness map creation unit 224 is a functional unit that creates a film thickness map. A film thickness map is a map that indicates the position (XY coordinates) and thickness (ΔTh) of a liquid film adhering to an object. When the distance measurement information obtained by the optical sensor 111 includes two distances, the film thickness map creation unit 224 creates a film thickness map by regarding the area between the two distances as a film.

[0026] By measuring the distance while rotating the processing head 122, to which the sensor head of the optical sensor 111 is attached, around the B axis, data with different B coordinate θ (tilt) is obtained, and the data is converted according to the tilt to create a film thickness map. The film thickness map creation unit 224 converts the data in accordance with equations (1) to (3), which will be described later.

[0027] The film thickness map creation unit 224 outputs the created film thickness map, the coordinate values ​​(X / Y / Z and B / C) set by the coordinate setting unit 221, and the distance measurement information supplied from the optical sensor 111 to the three-dimensional shape measurement unit 226.

[0028] (Three-dimensional shape measurement unit) The three-dimensional shape measurement unit 226 is a functional unit that creates a three-dimensional map based on the film thickness map, coordinate values, and distance measurement information. The three-dimensional map is created by combining distance measurement data of the object at the position where the film thickness was obtained. In other words, the three-dimensional map is created by combining distance measurement data of the object obtained at the rotation angle around the B axis (B coordinate θ) at which the film thickness data used to create the film thickness map was obtained. A specific method for creating the three-dimensional map will be described later.

[0029] (Determination Unit) The determination unit 227 is an additional functional unit that compares target information including target values ​​with measured 3D information and calculates the error between them. In other words, if the correct answer data is known in advance, the correct answer data may be compared with the created 3D map data. The determination unit 227 outputs the calculated error to the display device 240.

[0030] <Operation> Next, the operation of the machining device will be described with reference to FIG.

[0031] (Step ST201) In step ST201, the optical sensor 111 performs measurement at a rotation angle of 90 degrees around the B axis, and outputs the measurement result to the controller 200.

[0032] (Step ST202) In step ST202, the film thickness map creation unit 224 determines whether or not there is a film thickness (i.e., whether or not there is cutting oil). The determination of whether or not there is a film thickness is made based on whether or not two distances are included in the distance measurement results by the optical sensor 111. If two distances are included, it is determined that there is a film thickness, and if two distances are not included, it is determined that there is no film thickness.

[0033] (Step ST203) In step ST203, the film thickness map creation unit 224 creates a film thickness map at B=90 degrees. The film thickness map is a map defined by an XY coordinate system such as that shown in FIG. 4A, and is created in accordance with the presence of a film (liquid) as shown in FIG. 4B. The film thickness is measured in the areas marked "measurable" in FIG. 4B, but film thickness data is not obtained in the areas marked "unmeasurable." Since there is no film around the areas marked "unmeasurable," the film thickness is 0. The film thickness map stores measured film thickness data in association with each XY coordinate.

[0034] (Steps ST204 and ST205) The coordinate setting unit 221 changes the coordinate value of the C-axis in step ST204, and changes the coordinate value of the B-axis in step ST205. Note that the coordinate value of the C-axis is not changed for the first time. In other words, the coordinate value of the C-axis is changed after sufficient measurements have been performed with the coordinate value of the B-axis changed.

[0035] Furthermore, the B coordinate can be changed within a range of, for example, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm from the edge of the film in the film thickness map. Since the slope of the film edge is finite and does not continue indefinitely, it is sufficient to change the B coordinate within a range of at most 10 mm from the edge of the film in the film thickness map.

[0036] (Step ST206) In step ST206, the optical sensor 111 performs measurements at the changed angle. That is, measurements are performed at B coordinate values ​​of 80 degrees, 100 degrees, 70 degrees, 110 degrees, and so on. The optical sensor 111 outputs the measurement results to the controller 200. To improve measurement accuracy, measurements are performed by changing the angle to a smaller width. The film thickness map creation unit 224 creates a film thickness map for each B coordinate value from the measurement results.

[0037] (Steps ST207 and ST208) In step ST207, the coordinate setting unit 221 determines whether the change in the B-axis coordinate value is sufficient, and in step ST208, determines whether the change in the C-axis coordinate value is sufficient. Whether the change in the B-axis coordinate value is sufficient is determined, for example, by determining whether two distances are no longer included in the distance measurement results from the optical sensor 111 in a measurement after the B-axis coordinate value is changed from 90 degrees. Furthermore, whether the change in the C-axis coordinate value is sufficient may be determined according to measurement conditions received via the input device 210.

[0038] In step ST209, the film thickness map creating unit 224 performs coordinate conversion. For example, as shown in FIG. 5, a sensor head having a length L is attached to the tip of the processing head 122 having a stroke length L. ０ When the sensor head of the optical sensor 111 is attached, the coordinates are converted according to the following equations (1) to (3): X coordinate = X + (L + L ０ +ΔL)cosθ...(1) Y coordinate=Y...(2) Z coordinate=Z+(L+L ０ +ΔL)sinθ...(3)

[0039] Stroke length L and sensor head length L ０ are fixed values, and the film thickness map creating unit 224 acquires these values ​​from the input device 210 or the memory 230.

[0040] (Step ST210) In step ST210, the film thickness map creation unit 224 uses the coordinate-converted data to create a film thickness map by combining the film thicknesses created at multiple angles. FIG. 6 is a conceptual diagram illustrating the composition of film thickness maps. FIG. 6A shows film thicknesses measured at B coordinates of 70 degrees, 80 degrees, 90 degrees, 100 degrees, and 110 degrees. Measurements at each angle indicate whether a film thickness exists or not. Furthermore, due to surface tension, a film thickness should exist around the area where a film thickness is determined to exist based on the measurement at 90 degrees. Therefore, by sequentially combining film thicknesses obtained from film thickness maps at other B coordinate values ​​around the area where a film thickness exists obtained from the film thickness map at B coordinate = 90 degrees, a film thickness map is created that combines film thicknesses at multiple B coordinate values, as shown in FIG. 6B. In this way, a combined or corrected film thickness map can be created. This corrected film thickness map identifies the film thickness at each X- and Y-coordinate position. The film thickness data is linked to the B-axis coordinate data.

[0041] (Step ST211) In step ST211, the three-dimensional shape measuring unit 226 creates a distance measurement map from the corrected film thickness map, coordinate values ​​(X / Y / Z and B / C), and distance measurement data. The distance measurement map is a map that stores distance data at each XY coordinate of the measurement object. FIG. 7 is a graph showing distances measured at B coordinates of 70 degrees, 80 degrees, 90 degrees, 100 degrees, and 110 degrees. As can be seen from FIG. 7, the shape of the measurement object cannot be determined from the distance measurement data measured at each angle. This is because a film exists on the top surface of the measurement object. Therefore, the three-dimensional shape measuring unit 226 uses the corrected film thickness map to select distance measurement data for the B-axis coordinate value associated with the film thickness data if a film thickness exists in the corrected film thickness map, and synthesizes the selected data to create a distance measurement map. In this way, a distance measurement map consisting of multiple distance measurement data, as shown in FIG. 8, is synthesized from the distance measurement data of FIG. 7. Figure 8 shows a distance measurement map along a certain line, but a three-dimensional distance measurement map can be obtained by combining the distance measurement map of Figure 8 with multiple distance measurement maps along other multiple lines obtained by changing the value of the C coordinate.

[0042] (Step ST212) In step ST212, the three-dimensional shape measuring unit 226 performs display control to display a three-dimensional distance measurement map in 3D on the display device 240.

[0043] <Example> An example will be described below with reference to Figs. 9 and 10. Fig. 9A is a schematic diagram showing an object 81 with an oil film 82 attached thereto. Fig. 9B is ground truth data showing the shape of the object 81. Fig. 10A is a diagram showing distance measurement data of the object 81 measured when the B coordinate is 90 degrees. Fig. 10B is a diagram showing distance measurement data of the object 81 measured when the B coordinate is 80 degrees. Fig. 10C is a diagram showing distance measurement data of the object 81 measured when the B coordinate is 70 degrees. Fig. 10D is a diagram showing a distance measurement map created by combining R1 of Fig. 10A, R2 of Fig. 10A, and R3 of Fig. 10C.

[0044] As shown in Fig. 10D, the distance measurement map is generated by combining distance measurement data measured at multiple B coordinate values. Comparing the distance measurement map in Fig. 10D with the correct data in Fig. 9B, it can be seen that the distance measurement map properly represents the shape of the object 81. In the distance measurement map in Fig. 10D, a valley with a large drop in height (step shape) can be seen near the middle of the X-direction coordinate value between both end coordinates. This is because the data when the B coordinate is 100 degrees or 110 degrees is not combined.

[0045] According to the machining device described above, the distance measurement of the object is performed while rotating the machining head equipped with the optical sensor head. Therefore, even if a film such as an oil film is present on the object, the shape of the curved edge of the film due to surface tension can be measured and created as a film thickness map. The distance measurement map is created by combining the distance measurement data of the object obtained at the rotation angles of the sensor head or machining head used to create this film thickness map. Therefore, the shape of the film edge, which cannot be measured by simply facing the machining head, can be measured, and the three-dimensional shape of the object can be measured even if a film is present on the object. Using the machining device disclosed herein enables the process from machining to measurement of the object to be automated, contributing to the realization of remote factories.

[0046] It is possible to combine the embodiments, and to modify or omit each embodiment as appropriate.

[0047] The machining device of the present disclosure can be used as a device that performs processes from machining to measurement of an object.

[0048] 81 Object, 82 Oil film, 100 Processing machine, 110 Tool magazine, 111 Optical sensor, 120 Processing unit, 121 Processing head displacement means, 122 Processing head, 123 Cutting oil nozzle, 124 Stage, 125 Tool magazine displacement means, 200 Controller, 210 Input device, 220 Processor, 221 Coordinate setting unit, 222 Cutting oil supply control unit, 223 Tool magazine selection unit, 224 Film thickness map creation unit, 226 Three-dimensional shape measurement unit, 227 Determination unit, 230 Memory, 240 Display device.

Claims

1. A machining device comprising: a processing machine having a processing head for processing an object, the processing head being drivable along three mutually perpendicular linear axes and drivable around two rotational axes; an optical sensor having a sensor head and an optical sensor body and capable of measuring the distance to the object; a controller that controls the operation of the processing machine and measures the three-dimensional shape of the object based on distance measurement information from the optical sensor, wherein the sensor head of the optical sensor is attachable to the processing head of the processing machine, and the controller comprising: a coordinate setting unit that sets the coordinates of the processing head of the processing machine; a film thickness map creation unit that detects liquid present on the object based on the coordinates set by the coordinate setting unit and distance information measured by the optical sensor by driving the object around the rotational axis to relatively move the object, and creates a film thickness map that combines multiple position data indicating the location of the liquid present on the object and multiple thickness data indicating the thickness of the liquid; and a three-dimensional shape measurement unit that generates a three-dimensional map of the object by combining distance measurement data of the object obtained at the rotational angles at which each thickness data used to create the film thickness map was acquired.

2. An optical distance measuring method performed by a machining device comprising: a processing machine having a processing head for processing an object, the processing machine being drivable along three mutually perpendicular linear axes and drivable around two rotational axes; an optical sensor having a sensor head and an optical sensor body and capable of measuring the distance to the object; and a controller that controls the operation of the processing machine and measures the three-dimensional shape of the object based on the distance measurement information of the optical sensor, the sensor head of the optical sensor being attached to the processing head of the processing machine, the method comprising: a step in which the controller sets the coordinates of the processing head of the processing machine; a step in which the controller detects liquid present on the object based on the set coordinates and the distance information measured by the optical sensor by driving the object around the rotational axis to move it relatively, and creates a film thickness map that combines multiple position data indicating the location of the liquid present on the object and multiple thickness data indicating the thickness of the liquid; and a step in which the controller combines the distance measurement data of the object obtained at the rotational angle at which each thickness data used to create the film thickness map was acquired, to generate a three-dimensional map of the object.

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