Shape measurement system

Abstract

This system provides a shape measurement system that allows for easy measurement of workpiece shape while reducing the burden on the operator. [Solution] The shape measurement system 10 includes a controller 16 that generates a measurement program to image a workpiece 100 with a measurement camera 30 attached to the spindle head 18 of a machine tool 12. Based on the results of simulating the shape changes when the workpiece 100 is machined, the controller 16 identifies the portion whose shape has changed between a reference timing specified by the operator and a target timing as the measurement target range 70. Based on the shape model corresponding to the target timing and the camera characteristics including the field of view and depth of field of the measurement camera 30, the controller 16 identifies a plurality of imaging points 78 and generates the measurement program based on the identified plurality of imaging points 78.

Claims

[Claim 1] A shape measurement system, The system includes a controller that generates an NC program as a measurement program, which causes a measurement camera attached to the movable part of a machine tool to image the workpiece in order to acquire multiple measurement images necessary for measuring the surface shape of the workpiece. The aforementioned controller, The operator specifies the reference timing and target timing. Based on the results of simulating the shape change when the aforementioned workpiece is processed, the portion whose shape changed between the reference timing and the target timing is identified as the measurement target range. Based on the target model, which is a shape model corresponding to the target timing, and the camera characteristics including the angle of view and depth of field of the measurement camera, a plurality of imaging points for acquiring the plurality of measurement images are identified. Based on the identified plurality of imaging points, the measurement program is generated. A shape measurement system characterized by being configured in such a way. [Claim 2] A shape measurement system according to claim 1, The aforementioned controller, The initial model, which is a shape model corresponding to the aforementioned reference timing, and the target model are calculated by the aforementioned simulation. The difference range between the initial model and the target model is identified as the measurement target range. A shape measurement system characterized by being configured in such a way. [Claim 3] A shape measurement system according to claim 2, The controller is configured to determine the imaging point by calculating measurement points that are in a known positional relationship with the imaging point, and the measurable range corresponding to the measurement points. The measurable range is a three-dimensional range determined by the angle of view and depth of field of the measurement camera, a range in which the shape can be measured using an image captured at the imaging point defined by the measurement point, and a range in which the relative positional relationship with the measurement point is known. The controller is configured to calculate a plurality of measurement points such that the surface of the target model within the measurement target range is included in a plurality of measurable ranges corresponding to a plurality of measurement points. A shape measurement system characterized by the following features. [Claim 4] A shape measurement system according to claim 3, The shape measurement system is characterized in that the controller is further configured to calculate a plurality of measurement points such that offset surfaces, obtained by offsetting the surface of the target model in the measurement target range inward and outward by an amount equal to the assumed shape error, are all included in a plurality of measurable ranges corresponding to a plurality of measurement points. [Claim 5] A shape measurement system according to claim 4, The aforementioned controller, The projection range is identified by projecting the proximal end face of the measurable range corresponding to a provisional measurement point onto the surface of the target model in the direction of the optical axis of the measurement camera. A measurement point is identified that passes through the aforementioned provisional measurement point, lies on a straight line parallel to the optical axis direction, and whose projection range is inside the corresponding measurable range where the surface of the target model is located. Identify the imaging point corresponding to each of the identified measurement points. A shape measurement system characterized by being configured in such a way. [Claim 6] A shape measurement system according to claim 5, The controller is configured to measure the shape of an object captured in a single image based on that single image. The imaging point is the same as the measurement point. The measurable range is the range in which imaging can be performed with the image in focus at the imaging point. A shape measurement system characterized by the following features. [Claim 7] A shape measurement system according to claim 6, The controller is configured to measure the shape of an object located at the same location based on multiple images taken of the same location. One of the measurement points defines two of the imaging points, The two imaging points are two points whose optical axis axis position coincides with the measurement point and which are in a specified positional relationship with the measurement point. The aforementioned measurable range is the range in which the imaging ranges of each of the two imaging points overlap. The imaging range is the range in which imaging is possible at the corresponding imaging point while the image is in focus. A shape measurement system characterized by the following features. [Claim 8] A shape measurement system according to claim 5, The aforementioned controller, Among the multiple shape points constituting the surface of the target model in the projection range, the most distal point located on the distal side in the optical axis direction is identified. The measurement points are calculated such that the optical axis position of the distal end face of the measurable range coincides with the optical axis position of the most distal point. A shape measurement system characterized by being configured in such a way. [Claim 9] A shape measurement system according to claim 8, The shape measurement system is characterized in that the controller is configured to correct the identified measurement point by offsetting it distal to the optical axis by the amount of the expected shape error. [Claim 10] A shape measurement system according to claim 5, The controller is configured to set an additional measurement point between the first measurement point and the second measurement point if the difference in height in the optical axis direction between the first measurement point and the second measurement point adjacent to the first measurement point is greater than the optical axis dimension of the measurable range. The additional measurement point is positioned at least differently in the optical axis direction compared to the first measurement point or the second measurement point. A shape measurement system characterized by the following features. [Claim 11] A shape measurement system according to claim 5, The movable part is capable of changing the optical axis direction of the measurement camera. The controller is configured to specify not only the position of the imaging point, but also the imaging direction, which is the optical axis direction during imaging. The controller is configured to identify the imaging direction as a direction perpendicular to at least a portion of the surface of the projection range. A shape measurement system characterized by the following features. [Claim 12] A shape measurement system according to claim 5, The aforementioned controller, In the aforementioned target model, the outline line of the measurement target range is extracted, Multiple temporary points are set along the outline and inside the outline, aligned in a direction perpendicular to the optical axis. To identify the measurement point corresponding to each of the aforementioned plurality of provisional points, It is configured in such a way, The controller, in order to identify the measurement point, The projection range obtained by projecting the measurable range onto the surface of the target model, assuming the aforementioned provisional point is the measurement point, is identified. Of the multiple shape points constituting the aforementioned projection range, the most distal point located furthest towards the optical axis is identified. The measurement point is identified such that it passes through the provisional point and lies on a straight line parallel to the optical axis direction, and the optical axis position of the distal end face of the corresponding measurable range coincides with the optical axis position of the most distal point. A shape measurement system characterized by being configured in such a way. [Claim 13] A shape measurement system according to claim 1, further, The system comprises the aforementioned measuring camera and the aforementioned machine tool, The machine tool comprises a spindle head that can move while holding a tool, a tool magazine for storing multiple tools, and an ATC for exchanging tools between the tool magazine and the spindle head. The measuring camera is exchanged between the spindle head and the tool magazine by the ATC. A shape measurement system characterized by the following features.

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