JP2015132576A - Work-piece type specifying method of shape measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work specifying method that specifies the kind of a work and reduces the number of times of specifying the work by using a logical sum portion and exclusive OR of a plurality of kinds of work shapes having a possibility of existence for the plurality of works.SOLUTION: A work specifying method for specifying a kind of a work of a measurement object using a shape measuring device for measuring a shape of the work includes: a first determination step S104 of determining a partial region of the logical sum of a plurality of kinds of works to be a first specific region based on shape information or arrangement of a plurality of kinds of works; a second determination step S106 of determining the partial region of exclusive ORs of the plurality of kinds of works to be a second specific region; a measurement step S108 of measuring the first specific region or the second specific region; and a narrow-down step S109 of narrowing down the number of works of specified objects among the plurality of kinds of the works based on the measured result.

Description

  The present invention relates to a work type specifying method in shape measurement.

  Various three-dimensional shape measuring apparatuses that measure three-dimensional coordinates on the surface of a workpiece that is a measurement target and acquire a three-dimensional shape of the workpiece are known. Examples of the work include parts for automobiles, parts for precision instruments such as printers and cameras, and molds thereof. When measuring a plurality of types of these workpieces, there is a need for a three-dimensional measuring apparatus that automatically determines what type of workpiece to be measured next.

  Therefore, in Patent Document 1, in a state where there are a plurality of types of workpieces to be measured and the type of workpiece to be measured next is unknown, the three-dimensional shape measuring apparatus automatically determines the type of workpiece and specifies the type. A method for performing measurement suitable for the workpiece is disclosed.

  In the work specifying method of Patent Document 1, information on the measurement position and height of the work is held in the apparatus in advance, and the measurement value (height) at the measurement position is acquired and held for the actual work. The type of work is specified by collating with the database that has been kept. Here, the prior art will be described with reference to FIG. Fig.8 (a) is a figure which shows the position (horizontal axis) and height (vertical axis) of 10 types of workpiece | work 1-10 which may be measured with a three-dimensional shape measuring apparatus, and is the cross-sectional shape of a workpiece | work. Some are shown.

  In FIG. 8A, in order to specify the workpiece type, a plurality of measurement positions having different workpiece heights are designated. Here, for example, five positions of measurement positions 201 to 205 are designated. The height of these five locations is measured, and the type of workpiece can be specified by comparing with the height information held in the apparatus.

JP-A-9-229661

  However, in the conventional workpiece identification method, workpieces are identified using physical property values such as workpiece height. If the physical property values are the same between workpieces, the number of measurements for identification May increase, and the time for specifying may increase.

  FIG. 8B is a diagram showing the position (horizontal axis) and height (vertical axis) of another 10 types of workpieces 11 to 20, and the workpieces 11 to 20 can be measured by a three-dimensional shape measuring apparatus. Suppose that the work is a sex. Although these workpieces have the same height, the dimensions orthogonal to the height are different as shown in FIG. 8 (c).

  In this case, the type of the work cannot be specified unless measurements are made at 10 measurement positions 211 to 220 at the maximum. In other words, the number of times of measurement that is the same as the number of workpieces is required at the maximum, and the measurement time for specifying may increase.

  Therefore, the present invention has been made in view of the above problems, and provides a work specifying method for specifying a work type by using a logical product part and an exclusive OR of a plurality of types of work shapes that may exist. provide.

In order to solve the above problems, a work specifying method of the present invention is a work specifying method for specifying a type of a work to be measured using a shape measuring device for measuring the shape of a work, and a plurality of types Based on the shape information or arrangement information of the workpiece, based on the first determination step of determining one portion of the logical product area of the plurality of types of workpieces as the first specifying portion, and on the shape information or the arrangement information, A second determining step of determining one part of the exclusive OR region of a plurality of types of workpieces as a second specifying part; a measuring step of measuring the first specifying part or the second specifying part; A narrowing step for narrowing down the number of workpieces to be identified among a plurality of types of workpieces based on the measurement results, and when the workpiece to be identified is narrowed down to one type in the narrowing step, the measurement pair The work and specifying as a work narrowed the.

  According to the present invention, for a plurality of workpieces, the types of workpieces are identified using the logical product portion and exclusive OR of a plurality of types of workpiece shapes that may exist, and the number of workpieces specified is reduced. A work identification method can be provided.

It is a figure which shows the whole structure of the three-dimensional shape measuring apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the workpiece | work identification method which concerns on one Embodiment of this invention. It is a figure which shows the workpiece | work specific flow which concerns on one Embodiment of this invention. It is a figure which shows the workpiece | work specific operation | movement which concerns on one Embodiment of this invention. It is a figure explaining the probability of the workpiece | work specific frequency | count which concerns on one Embodiment of this invention. It is a figure which shows the workpiece | work arrangement | positioning which concerns on 2nd Embodiment of this invention. It is a figure explaining grouping of the work concerning a 2nd embodiment of the present invention. It is a figure which shows the workpiece | work identification method of a prior art.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
A three-dimensional shape measuring apparatus suitable for the work specifying method of the present embodiment will be described with reference to FIG. In the configuration of the three-dimensional shape measuring apparatus of the present embodiment, an XYZ stage 32 is installed on the surface plate 31, and a rotating stage 33 and a measuring head 34 are installed on the XYZ stage 32. And the three-dimensional coordinate on the surface of the workpiece | work 35 is measured by the measurement head 34 (measurement part).

  A configuration like the XYZ stage 32 shown in FIG. 1 is generally called a gate type. However, the stage is not limited to the configuration of the present embodiment, and may be another articulated type or arm type stage. The measuring head 34 measures a workpiece and may have a contact type probe or a non-contact probe using light or the like.

  In the present embodiment, as a work to be specified, attention is mainly focused on a press-molded product for automobiles and a press-molded product for precision equipment. Some of these press-molded products have similar thicknesses and heights. In the three-dimensional shape measuring apparatus according to the present embodiment, for example, assuming that 10 types of workpieces are measured, workpieces 11 to 21 are simplified and shown in FIG. 4A described later. . Similar to FIG. 8B, these workpieces have the same height but different dimensions.

  Next, a work specifying method will be described with reference to FIG. First, in step S101, the shape data of the workpiece and the information on the position of the workpiece in the shape measuring device are registered in advance in a storage device (not shown) of the shape measuring device or a storage device of an external processing device (not shown).

  Here, the workpiece shape data is workpiece design three-dimensional CAD data or three-dimensional shape data acquired in advance by a shape measuring apparatus. Depending on the workpiece, a dedicated workpiece holder may be used to fix the workpiece, or the same workpiece holder may be used for different workpieces. For this reason, it is difficult to specify a workpiece only with this shape data.

  In this case, in order to avoid physical interference in the later-described probe operation, it is necessary to consider the shape of the workpiece holder and the arrangement position in the shape measuring device. Therefore, in addition to the shape data of the workpiece and the arrangement position in the shape measurement device, the shape data of the workpiece holder and the information on the arrangement position in the shape measurement device are also registered in the shape measurement device or the processing device.

  Next, in step S102, the number of work types that may exist is checked. If the number of work types is one (Yes), the process proceeds to step S110, and the process ends. On the other hand, when the number of workpieces is not one (No), that is, when there are two or more types, the process proceeds to step S103. In addition, after step S102, it is executed by an arithmetic processing unit (arithmetic unit) that identifies the type of workpiece to be measured, such as a CPU.

  Next, in step S103, the number of types of workpieces that may exist is checked. If the number of workpieces is not two (No), that is, if there are three or more types of workpieces, the process proceeds to step S104, and there are two types of workpieces. If there is (Yes), the process proceeds to step S106.

  Next, in step S104, a first specifying part for specifying the work type is determined. The first specifying part is one part of a logical product part of a plurality of types of workpiece shapes whose workpiece types are unknown. The selection method of the first specifying part is a selection method that requires the smallest number of maximum measurements for specifying a workpiece, or a selection method that calculates the expected value of the number of measurement times and has the smallest expected value.

  Here, this specific part will be specifically described. The same applies to the second specifying part in step S106. Since the part for identification need only detect the workpiece, it can be measured easily. For example, one point on the surface of the workpiece may be specified, but multiple points or a surface of a specific area may be specified. In order to improve the accuracy, a characteristic shape such as a cylinder or an edge portion may be designated. Also, when the probe is non-contact, there is a measurable space range depending on the depth in the optical axis direction and the incident angle that can be applied to the workpiece surface, so the logical product part of the work shape included in the measurable space range is specified It may be a site for use.

  Next, in step S105, it is determined whether or not a measurable first specifying part exists. If there is a measurable first specifying part (Yes), the process proceeds to step S107, and a measurable first specifying part is found. If one specifying part does not exist (No), the process proceeds to step S106.

  In step S106, a second specifying part for specifying the work type is determined. The second specifying part is one part of an exclusive OR part of a plurality of types of workpiece shapes whose workpiece types are unknown. The second specifying part is determined using the same method as that for determining the first specifying part.

  Next, in step S107, the first or second specifying part determined in step S104 or step S106 is measured, and a specific operation for narrowing down the work type is determined. In order to determine the specific operation, the logical sum part of all types of shapes of the workpieces that have not been narrowed down to step S107 is first calculated, and the above-described first or second specific condition is obtained without interference between the logical sum part and the probe. The operation (specific operation) of the probe that can measure the site to be used is determined.

  For example, in FIG. 8B, since the type of the workpiece is unknown at the beginning of the measurement, an operation that moves the probe while avoiding the logical sum portion of all the shapes of the workpieces 11 to 20 is determined. When the work pieces 16 to 20 are narrowed down, the works 11 to 15 do not exist and are excluded, and an operation that avoids the logical sum portion 210 of the shapes of the works 16 to 20 surrounded by a dotted line may be determined. When determining the specific operation, if shape data or the like of the workpiece holder is registered, the specific operation is determined in consideration of the workpiece holder. By this specific operation, it is possible to avoid the probe from colliding with the workpiece or the workpiece holder, and automatic specification without subsequent human operation and subsequent automatic measurement are possible.

  Next, in step S108, the probe is operated based on the specific operation determined in step S107, and the first or second specifying site determined in step S104 or step S106 is measured. In step S109, work types are narrowed down based on the result measured in step S108. That is, the first or second specifying part is measured to determine whether or not a work exists. If a workpiece exists, the number of workpiece types that may exist is calculated. On the other hand, if there is no work, the number of work types that may exist that are not included is calculated.

  In step S109, after narrowing down the work types, the process returns to step S102 to check again the number of work types that may exist. Then, the processes in steps S102 to S109 are repeated until the number of work types that may exist in step S102 is one. When the number of workpiece types is one, the processing is terminated assuming that the workpiece types can be specified.

  Next, a specific flow when a workpiece is identified by applying the workpiece identification method described above will be described with reference to FIGS. In the present embodiment, a case where the workpiece 19 is specified from the workpieces 11 to 20 will be described. FIG. 3 is a diagram specifically illustrating a flow of the work identification method illustrated in FIG. 2, and FIG. 4 is a diagram illustrating an operation for specific workpiece identification.

  First, referring to FIG. 3, in STEP 101 (step S <b> 101), the three-dimensional CAD data (shape information) of the workpieces 11 to 21 described in FIG. In STEP 102, since the number of registered work types is 10, the process proceeds to STEP 103, and further proceeds to STEP 104.

  Next, in STEP 104, the measurement position 215 that is one part of the logical product portion of the workpieces 11 to 15 in FIG. 4A is determined as the first specifying part for the first time. The measurement position 215 can be selected by one of the selection methods that requires the smallest number of maximum measurements. In addition, for example, as shown in FIG. 8B, at a measurement position 214 that is one part of the logical product part of the workpieces 11 to 14, a measurement position 216 that is one part of the logical product part of the works 11 to 16, and the like. There may be.

  Next, in STEP 105, since there is a measurable first specifying part, the process proceeds to STEP 107. In STEP 107, as a specific operation for measuring the measurement position 215 that is the first first specifying part in FIG. 4A, the logical sum 221 (portion surrounded by a dotted line) of the workpieces 11 to 20 is avoided. The route 222 is determined. In STEP 108, the probe is operated along the path 222, and the measurement position 215 that is the first specifying part is measured.

  As a measurement result in STEP 108, since there is no workpiece, in STEP 109, the number of remaining workpiece types that may exist is calculated. That is, it is a kind of work in which works 16 to 20 excluding works 11 to 15 may exist, and the number thereof is five. Then, returning to STEP 102, the second process is performed.

  In the second process, first, in STEP 102, since the number of work types is calculated to be five in the first STEP 109, the process proceeds to STEP 103, and further proceeds to STEP 104. Next, in STEP 104, a measurement position 218, which is one part of the logical product portion of the workpieces 16 to 20 in FIG. 4B, is determined as the second first specifying part. In FIG. 4B, the workpieces 11 to 15 that have been confirmed not to exist in the first process are excluded.

  Next, in STEP 105, since there is a measurable first specifying part, the process proceeds to STEP 107. In STEP 107, as a specific operation for measuring the measurement position 218, which is the second first specifying portion in FIG. 4B, the logical sum portion 223 (portion surrounded by a dotted line) of the workpieces 16 to 20 is avoided. The route 224 is determined. In STEP 108, the probe is operated along the path 224, and the measurement position 218, which is the second specifying part, is measured.

  As a measurement result in STEP 108, since there is no workpiece, in STEP 109, the number of remaining workpiece types that may exist is calculated. That is, the workpieces 19 to 20 excluding the workpieces 16 to 18 may exist, and the number of the workpieces is two. Then, returning to STEP 102, the third process is advanced.

  In the third process, first, in STEP 102, since the number of work types is calculated in STEP 109 in the second time, the process proceeds to STEP 103, and further proceeds to STEP 106. Next, in STEP 106, a measurement position 219 that is one part of the exclusive OR part of the workpieces 19 to 20 in FIG. 4C is determined as the second specifying part. In FIG. 4C, the workpieces 16 to 18 that have been confirmed not to exist in the second process are excluded.

  Next, in STEP 107, as a specific operation for measuring the measurement position 219, which is the third second specifying portion in FIG. 4C, a logical sum portion 225 (portion surrounded by a dotted line) of the workpieces 19-20. A route 226 that avoids the above is determined. In STEP 108, the probe is operated along the path 226, and the measurement position 219, which is the second specifying part, is measured.

  As a measurement result in STEP 108, since a workpiece exists, the number of types of workpieces that may exist is calculated in STEP 109. That is, the work type that may exist is the work 19, and the number thereof is one. Accordingly, the process returns to STEP 102, proceeds to STEP 110, and ends the process. In the present embodiment, the workpiece 19 can be specified by three measurements.

  In the prior art, since the workpiece is specified by measuring the portion where the height differs between workpieces, it can be said that the logical difference portion is measured. When a workpiece is specified from a plurality of workpieces having the same height as in the present embodiment using conventional technology, for example, when the workpiece 20 is specified in FIG. It is necessary to exclude workpieces that do not exist by sequentially measuring. In this case, the expected value of the number of times of measurement is 1 * 1/10 + 2 * 1/10 +... 10 * 1 / if the probability that any of the workpieces that actually exist is 11 to 20 is equally 1/10. 10 = 5.5 times.

  On the other hand, in the present embodiment, since the workpiece is specified using the logical product portion of the workpiece shape, the maximum number of measurement times can be reduced. Using the method for selecting the first specifying part as described above, the number of measurements and the probability at that time when the probability that the workpiece to be identified is any one of the workpieces 11 to 20 are equally 1/10. As shown in FIG. The maximum number of times of measurement is 4 times when the work to be identified is any one of the work 11, 12, 16, and 17, and the expected value of the number of times of measurement is 1 * 0 + 2 * 0 + 3 * (0.1 + 0.2 + 0) .1 + 0.2) + 4 * 0.2 * 2 = 3.4 times.

  As described above, according to the present embodiment, when a workpiece is specified from a plurality of workpieces, the workpiece can be identified by measuring with a smaller number of times than the conventional workpiece identification method, and the time required for workpiece identification is also shortened. It becomes possible to do.

(Second Embodiment)
In the first embodiment, the case has been described in which the in-device arrangement of the workpiece to be measured is a (predetermined) arrangement suitable for the workpiece identification method. In the present embodiment, the arrangement when the arrangement of the workpiece to be measured in the apparatus is not suitable will be described. The shape measuring apparatus according to this embodiment is the same as that of the first embodiment, and a detailed description thereof is omitted.

  Fig.6 (a) is a figure which simplifies and shows the workpieces 41-50 in this embodiment. In the figure, the vertical axis indicates the height of the workpiece, and the horizontal axis indicates the position where the workpiece is arranged. As shown in FIG. 6A, the heights of the workpieces 41 to 50 are the same, but the dimensions orthogonal to the height of the workpieces are different from each other as in FIG. 8B. In addition, the workpiece | work 41-50 shown to Fig.6 (a) is arrangement | positioning which is not suitable for a workpiece | work identification method.

  In this case, if the workpiece is specified by using the conventional workpiece identification method, as shown in the first embodiment, the measurement needs to be performed 10 times at the maximum, and the expected value of the number of measurements is also 5.5 times. It becomes. Further, in this case, when the work specifying method of the first embodiment is applied, there is no logical product part of the work shape, so that the maximum number of measurements is required 10 times as in the prior art, and the expected number of measurements. Is 5.5 times.

  Therefore, a method for generating an in-device arrangement of a workpiece for generating a logical product portion of the workpiece shape that is suitable for the workpiece identification method shown in the first embodiment will be described. The method for generating the in-device arrangement of the work is to determine the arrangement by adjusting the arrangement so that two or more minimum number of logical product parts are generated and dividing the logical product part into a group sharing the logical product parts. It is. An example of grouping will be described in detail with reference to FIG.

  FIG. 7 is an image diagram showing a method for generating the arrangement in the work apparatus. In FIG. 7, the group 80 includes all works that may exist. Next, this group 80 is divided into two groups. That is, a group 81 including approximately 10% to 90% of the work types of the group 80 and a group 82 including the remaining works are generated.

  The workpieces in the group 81 are arranged so that logical product portions 810 of all the shapes are generated, and the workpieces in the group 82 are arranged so that logical product portions 820 of all the shapes are generated. It is assumed that the logical product part 810 and the logical product part 820 do not have a common part.

  Ideally, two groups are good. For example, if the number of logical product parts of the workpiece shape is not one in the group 81 due to restrictions on the work placement, the group 81 is further divided into two groups. Also good. Therefore, the groups 81 and 82 are further divided into two groups in the same manner as described above, and an arrangement in which a logical product portion of the work shape is generated in each group is generated. At this time, the logical product generated in the groups 81 and 82 is prevented from disappearing.

  In this manner, the above grouping is repeated until the group finally includes two works. The in-device arrangement information of the workpiece generated in this way is registered, and the workpiece is arranged according to the in-device arrangement and the workpiece is specified and measured. For example, when the total number of workpieces is 100, the workpiece can be identified by measuring up to seven times if it can be ideally arranged in the apparatus by repeating two groupings to identify the workpiece.

  A method for determining the arrangement of the workpieces in the apparatus will be described with reference to FIG. As described above, the workpieces 41 to 50 shown in FIG. 6A are shown in an arrangement that is not suitable for the workpiece identification method. Among these, the workpieces 41 to 45 are grouped and rearranged so that a logical product portion of the workpiece shapes is generated. The result of the rearrangement is the group 81 in FIG. 6B, and the remaining works 46 to 50 are similarly grouped and rearranged to become the group 82.

  The logical product part of the group 81 is the logical product part 810 in FIG. 6B, and the logical product part of the group 82 is the logical product part 820 in FIG. 6B. At this time, if the works 49 and 50 of the group 81 are regarded as the group 81a and the works 46 to 48 are regarded as the group 81b, the logical product portion of the group 81a is 810a (common with 810 in this case), and the logical product of the group 81b. The portion is 810b. In this case, further grouping has already been completed.

  Similarly, assuming that the works 44 and 45 of the group 82 are the group 82a and the works 41 to 43 are the group 82b, the logical product part of the group 82a is 820a (common with 820 in this case), and the logical product part of the group 82b. Is 820b. In this way, an arrangement suitable for workpiece identification is generated.

  By arranging the work as shown in FIG. 6B and using the work identification method shown in the first embodiment using the arrangement information, it is possible to reduce the number of measurements for the work identification. . In this case, as in the first embodiment, the maximum value of the number of measurements is 4, and the expected value of the number of measurements is 3.4, so that the measurement time can be shortened.

In the above embodiment, the case where the height (thickness) of each workpiece is the same has been described. However, the height of the workpiece is not limited to the same, and may be different from each other.
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

11 to 20 Work pieces having the same thickness but different sizes 215, 218, 219 Measurement positions 221, 223, 225 Logical sum portion 222, 224, 226 of logical work that may exist

Claims (8)

A workpiece identification method for identifying the type of workpiece to be measured using a shape measuring device that measures the shape of a workpiece,
A first determination step of determining one part of a logical product area of a plurality of types of work as a first specifying part based on shape information or arrangement information of the plurality of types of work;
A second determining step of determining, as a second specifying part, one part of an exclusive OR region of a plurality of types of workpieces based on the shape information or the arrangement information;
A measuring step of measuring the first specifying part or the second specifying part;
Based on the measurement result, a narrowing step for narrowing down the number of workpieces to be identified among a plurality of types of workpieces;
Have
In the narrowing-down process, when the workpiece to be identified is narrowed down to one type, the workpiece identification method is characterized in that the workpiece to be measured is identified as the narrowed workpiece. When the specific target workpiece is not narrowed down to one type in the narrowing-down process, and when the specific target workpiece is two types, or when the measurement of the first specific part is not possible,
In the second determination step, the second specifying part is determined for a plurality of types of works narrowed down,
In the measurement step, the determined second specifying part is measured,
The work specifying method according to claim 1, wherein, in the narrowing-down process, the number of workpieces to be specified among a plurality of types of workpieces is narrowed down based on a result of the measurement. The work specifying method according to claim 1 or 2, wherein the first specifying part or the second specifying part is determined so that the maximum number of times of measurement for specifying the work is the smallest. The work specifying method according to claim 1 or 2, wherein the first specifying part or the second specifying part is determined such that an expected value of the number of times of measurement is the smallest.   The work specifying method according to any one of claims 1 to 4, further comprising a registration step of registering shape information or arrangement information of a plurality of types of works. The work specifying method according to claim 5, wherein when using a work holder, the shape information and arrangement information of the work holder are further registered in the registration step. The arrangement process according to any one of claims 1 to 6, further comprising an arrangement step of arranging the workpieces so that a minimum of two or more logical product portions are generated when the workpieces are not in a predetermined arrangement. Work identification method. A shape measuring device for measuring the shape of a workpiece,
A measuring unit for measuring the workpiece;
A calculation unit that identifies the type of workpiece to be measured,
The computing unit is
Based on the shape information or arrangement information of a plurality of types of workpieces, one part of the logical product area of the plurality of types of workpieces is determined as the first specifying part,
Based on the shape information or the arrangement information, determine one part of the exclusive OR region of a plurality of types of work as a second specifying part,
Based on the measurement result of the first specifying part or the second specifying part, the measurement unit narrows down the number of works to be specified among a plurality of kinds of works,
A shape measuring apparatus characterized in that when a workpiece to be specified is narrowed down to one type, the workpiece to be measured is identified as the narrowed workpiece.

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