JP7726400B2 - Gap inspection method and gap inspection device - Google Patents

Description

The present invention relates to a gap inspection method and a gap inspection device for inspecting the distance between a first part and a second part in an assembly comprising multiple parts, including a first rigid part and a second non-rigid part.

For example, during the inspection process for completed automobiles, a worker may use a ruler to measure the distance between two of several parts arranged in the engine compartment. This can be difficult to measure, as the ruler must be moved to the back of the engine compartment multiple times to avoid interference with other parts. Furthermore, there is a risk that the distance measurements will vary depending on the worker's level of skill.

Patent Document 1 also discloses a gap inspection method for measuring the spatial distance between a first rigid part and a second rigid part of an assembly. This gap inspection method measures the distance between the two parts based on three-dimensional data, which is the design data for the first part, and three-dimensional data, which is the design data for the second part.

However, in an assembly made up of multiple parts, not all parts are necessarily rigid; when the assembly contains both rigid and non-rigid parts, there is a need to measure the distance between the rigid and non-rigid parts.

The present invention has been made in response to such needs and provides a gap inspection method and gap inspection device that can calculate the distance between a first rigid part and a second non-rigid part in an assembly by scanning from the outside.

JP 2017-10342 A

The present invention is a gap inspection method for inspecting the distance between a first part and a second part in an assembly formed by assembling multiple parts, including a rigid first part and a non-rigid second part. The method involves scanning an area including the first part and the second part from the outside using a 3D sensor to obtain measurement data including a portion of the outer surface of each part, obtaining design data including the outer shapes of each of the first and second parts and their relative positions within the assembly, aligning the design data of the first part as a rigid body to the position of the measurement data of the first part to generate the outer shape of the first part including the hidden outer surface portion, aligning the design data of the second part as a non-rigid body to the position of the design data of the second part to generate the outer shape of the second part including the hidden outer surface portion, and calculating the distance between any point on the first part and any point on the second part.

The present invention allows for the distance between a first rigid part and a second non-rigid part in an assembly to be calculated by scanning from the outside.

FIG. 2 is an explanatory diagram showing various components in an engine compartment of the embodiment as viewed from above. 1 is a schematic diagram of a gap inspection device according to an embodiment of the present invention. This is point cloud data of the engine room and its internal parts scanned using a 3D laser scanner. This is point cloud data of the engine compartment and its internal components, showing a progress rate of 40%. FIG. 10 is an explanatory diagram of reliability. FIG. 10 is an explanatory diagram showing an indication of the displacement amount of the fuel tube on the display. 1 is a flowchart showing a gap inspection method according to the present embodiment.

An embodiment of the present invention will now be described with reference to the drawings. In this embodiment, the present invention is applied to a gap inspection that identifies the spatial positions of two parts in the engine compartment during the finished vehicle inspection process and calculates the minimum gap between them.

Figure 1 is a top view of some of the various components in an automobile engine compartment 1, which is an assembly of one embodiment, showing the area near the engine's intake manifold 2. An ignition coil 3, which is part of the engine's ignition system, is located below the intake manifold 2. A fuel tube 4, which supplies fuel to the engine, is located to the side of the intake manifold 2. The fuel tube 4 is made of a metal tube designed for oil resistance and fire resistance, and has a circular cross section along its radial direction. As shown in Figure 1, the fuel tube 4 has a straight portion 4a that extends generally linearly along the side of the intake manifold 2 and an inclined portion 4b that slopes from one end of the straight portion 4a toward the ignition coil 3. The fuel tube 4, made of a metal tube, undergoes some deformation during installation and is therefore considered a non-rigid component. On the other hand, the ignition coil 3 is considered a rigid component whose external shape does not change. The minimum spatial distance (minimum gap) between the ignition coil 3 and the fuel tube 4 is regulated by law, and therefore inspection of this minimum gap is required during the finished vehicle inspection process. In many cases, the design minimum distance between the ignition coil 3 and the fuel tube 4 is regulated at a position on the outer surface of at least one of the ignition coil 3 or the fuel tube 4 that is not visible from the outside, and it is generally difficult for an inspector to measure using a ruler. In this embodiment, the gap between these two parts is determined by external measurement using a three-dimensional sensor and calculation processing.

In addition to the intake manifold 2, ignition coil 3, and fuel tube 4, several other components are provided within the engine compartment 1. In the completed vehicle inspection process for this embodiment, the distance between the ignition coil 3 and the fuel tube 4 is inspected in a vehicle assembled from several components, including the ignition coil 3, which is a rigid component, and the fuel tube 4, which is a non-rigid component that takes into account deformation of its shape.

As shown in Figure 2, one embodiment of a gap inspection device used in the finished vehicle inspection process for automobiles is primarily composed of a three-dimensional sensor, such as a three-dimensional laser scanner 5, a database 6, a control device 7, and one or more displays 8. In the finished vehicle inspection process, a number of inspections are carried out sequentially in a predetermined order. The gap inspection device of one embodiment is configured as part of the inspection equipment in the finished vehicle inspection process.

The 3D laser scanner 5 can obtain the 3D coordinates of the surface shape of the measurement target by irradiating the measurement target with a laser and measuring the reflection time. By performing measurements at a high speed of approximately tens of thousands of points per second, high-density point cloud data can be obtained. Various sizes and types of 3D laser scanners are known. In one embodiment, a type that can be held by an operator and used to scan the measurement target is used. The target area is measured by manually scanning the area including the ignition coil 3, the fuel tube 4, and other components from the outside. Scanning with this 3D laser scanner 5 obtains point cloud data of the entire area including a portion of the outer surface of the ignition coil 3 and the fuel tube 4, as shown in FIG. 3 .
Although the point cloud data is actually acquired as time-series data for each frame by scanning, point cloud data for the entire area is acquired by overlaying the data. It is also desirable to perform noise reduction processing on the acquired point cloud data to remove noise caused by dust or other particles that may have been introduced during scanning. The 3D laser scanner may also require markers to serve as references for identifying the shape and position of the target part during scanning.

In this invention, "scanning" is a concept that includes either or both of the planar scanning function of the 3D sensor (e.g., 3D laser scanner 5) itself and the movement of the 3D sensor by, for example, an operator. In one embodiment, scanning is performed by using a 3D laser scanner 5 with planar scanning function and then moving this 3D laser scanner 5. Depending on the size and shape of the target area to be measured or the type of 3D sensor, it is also possible, for example, to place multiple 3D sensors fixedly in appropriate positions in space and use the scanning function of each 3D sensor to acquire point cloud data of the target area.

Database 6 stores all design data for the vehicle being inspected. Therefore, shape data for the ignition coil 3 and fuel tube 4, which are the subjects of gap inspection, are stored as design data, along with data showing their spatial relationship. Furthermore, database 6 also stores shape data and positional relationship data for other parts present within the area. The design data is stored in the database 6 in the form of CAD data constituting a mesh. During gap inspection, the necessary design data is read from database 6 to control device 7. After the design data is read into control device 7, known hidden surface processing may be applied to areas other than those involved in the gap between the ignition coil 3 and fuel tube 4 to reduce the data size.

The control device 7 first aligns the design data of the ignition coil 3 as a rigid body with the position of the measurement data of the ignition coil 3 to generate the outer shape of the ignition coil 3, including any hidden outer surface portions, and then aligns the design data of the fuel tube 4 as a non-rigid body with the position of the measurement data of the fuel tube 4 to perform various processes to generate the outer shape of the fuel tube 4, including any hidden outer surface portions.The control device 7 then calculates the distance between any point on the ignition coil 3 and any point on the fuel tube 4 based on the generated outer shapes of the ignition coil 3 and the fuel tube 4. Each component of the control device 7 will be described in detail below.

The display 8 displays the required displacement (movement) and location of the fuel tube 4 when the minimum distance calculated by the control device 7 is less than the threshold value specified by law.

We will now explain each component of the control device 7. As shown in Figure 2, the control device 7 has a first alignment unit 7a, a progress calculation unit 7b, a second alignment unit (rigid alignment unit) 7c, a third alignment unit (non-rigid alignment unit) 7d, a reliability calculation unit 7e, a first interpolation unit 7f, a second interpolation unit 7g, a distance calculation unit 7h, and a displacement calculation unit 7i.

The first alignment unit 7a roughly aligns the entire target area (the so-called target area in alignment) including the ignition coil 3, fuel tube 4, and other components in the measurement data acquired by the 3D laser scanner 5 with the entire area (the so-called reference area in alignment) including the ignition coil 3, fuel tube 4, and other components in the design data stored in the database 6. More specifically, the first alignment unit 7a uses the FPFH algorithm to search for keypoints in the point cloud data for the entire target area and describe the characteristics of these keypoints, such as the normal vectors of the keypoints and the relative angles of the surroundings. Furthermore, the first alignment unit 7a converts the design data for the entire reference area into point cloud data using a well-known conversion method, and then similarly uses the FPFH algorithm to search for keypoints and describe the characteristics of these keypoints, such as the normal vectors of the keypoints and the relative angles of the surroundings. The first alignment unit 7a then compares the normal vectors between the target keypoints and the reference keypoints and their relative angles with the surrounding point clouds to search for a pair of keypoints whose normal vectors and relative angles approximately match, and then roughly aligns the point cloud data of the reference with the point cloud data of the target using the pair of keypoints. Note that during this rough alignment, the non-rigid fuel tube 4 is considered to be a rigid body, and as a result, for example, an average alignment is performed within the length of the fuel tube 4. The rough alignment of the target region by the first alignment unit 7a is performed in parallel with the progress of scanning the target region. The first alignment unit 7a may also perform rough alignment of the target region using a known algorithm other than the FPFH algorithm.

The progress calculation unit 7b calculates the progress of the scanning required within the target area after the rough alignment performed by the first alignment unit 7a and before the detailed alignment of the ignition coil 3 and the fuel tube 4 (described below). In other words, the progress calculation unit 7b calculates the scanning progress from the ratio between the number of points in the point cloud data of the target area based on the reference design data and the number of points matched between the reference and the target through the rough alignment performed by the first alignment unit 7a. The progress calculation unit 7b further compares the calculated progress with a predetermined progress threshold (e.g., 40% in this embodiment) and determines in real time whether the progress, which gradually increases as the scanning progresses, has exceeded this progress threshold. For example, information on the current progress and whether this progress has exceeded the progress threshold is displayed on the display 8 via an information output unit (not shown). The operator then continues scanning using the 3D laser scanner 5 according to this display. In other words, scanning by the 3D laser scanner 5 (generation of point cloud data), rough alignment, and progress calculation are repeated in real time until a predetermined progress threshold is exceeded. For example, the area surrounded by the dashed line in Figure 4 corresponds to a progress of 40%.

In addition to the ratio of the number of data points as described above, the degree of progress may also be evaluated based on the number of viewpoints passed by the 3D laser scanner 5, the number of key points used in rough alignment, etc.

Since the basic shape or configuration of the area to be scanned is known as design data obtained from database 6, it is possible to estimate the spatial position of 3D laser scanner 5 and its movement trajectory, including its movement trajectory, based on the point cloud data sequentially obtained from 3D laser scanner 5. The progress of scanning can then be calculated based on how much of the distance scanned by 3D laser scanner 5 is included in the length of this movement trajectory.

In addition, multiple representative viewpoints are pre-defined for the viewpoint at the position of the 3D laser scanner 5, and the progress of scanning can be determined based on how many representative viewpoints the 3D laser scanner 5 passes through before drawing a movement trajectory.

Furthermore, the maximum number of key points is determined based on the point cloud data converted from the design data, so the progress of scanning can be calculated by calculating the ratio of key points based on the point cloud data converted from the measurement data to this maximum number of key points.

The second alignment unit 7c performs detailed spatial alignment for each component, provided that the progress rate exceeds 40%. That is, the second alignment unit 7c searches for paired points in the reference point cloud data for all points in the target point cloud data obtained by measuring the ignition coil 3 and fuel tube 4, and performs detailed alignment of the reference point cloud data with the target point cloud data. The non-rigid fuel tube 4 is considered to be a rigid body here, and as a result, average alignment is performed within the length of the fuel tube 4. The detailed alignment in the second alignment unit 7c can be performed using an appropriate known algorithm.

After detailed alignment by the second alignment unit 7c, the third alignment unit 7d performs non-rigid alignment of non-rigid components (in this example, the fuel tube 4) taking deformation into account. Any known algorithm can be used here. For example, nearest-neighbor pairs are searched for from the reference point cloud data and target point cloud data, which have been previously aligned as rigid bodies, and rotation, scaling, and translation parameters are calculated to bring the paired points closer together. For example, the outer shape of the fuel tube 4 is downsampled to form an outer surface composed of multiple triangles with vertices and edges. The vertices representing each downsampled region, i.e., the point cloud (cluster) of each region containing multiple adjacent triangles, are used to decompose the deformation of the cluster into rotation, scaling, and translation parameters, with the constraint that the edge length does not change (strictly speaking, the length change is minimized). The deformation of the entire fuel tube 4 is obtained as a collection of such cluster-based deformations. The third alignment unit 7d uses a non-rigid alignment method that takes such deformation into consideration to align the reference point cloud data for the fuel tube 4 with the target point cloud data in space while deforming the reference point cloud data for the fuel tube 4.

The reliability calculation unit 7e calculates the reliability of the alignment of each target component (i.e., the ignition coil 3 and the fuel tube 4). In other words, the reliability calculation unit 7e calculates the reliability indicating how closely the target point cloud data fits within the aligned reference point cloud data for each of the ignition coil 3 and the fuel tube 4.

Figure 5 is an explanatory diagram that shows a schematic representation of point cloud data of a fuel tube 4 after alignment, in order to explain reliability. For simplicity's sake, it is assumed here that the circular outer surface of a cross section of the fuel tube 4 is formed by 13 pieces of point cloud data. The 13 pieces of point cloud data Dr arranged in a circle are reference point cloud data based on design data, and the seven pieces of point cloud data Dt arranged in a semicircle are target point cloud data based on measurement data. For example, if scanning using the 3D laser scanner 5 is performed only from the top of the figure, the lower half will be an area that was not scanned (a missing area), and the target point cloud data Dt will be arranged in a semicircle.

Reliability is expressed, for example, as the ratio of the number of points in the reference point cloud data Dr to the number of points in the target point cloud data Dt within a radius L from each point in the reference point cloud data Dr. In the figure, the range of radius L from the numerous points in the reference point cloud data Dr is represented by the outer circle C1 and inner circle C2, each indicated by a dashed line. In the example shown in Figure 5(a), four target point cloud data Dt are included within the range R of the circles C1 and C2, resulting in a reliability of 4/13. In the example shown in Figure 5(b), two target point cloud data Dt are included within the range R of the circles C1 and C2, resulting in a reliability of 2/13. In the example shown in Figure 5(c), all of the target points, i.e., seven point cloud data Dt, are included within the region R, resulting in a reliability of 7/13. Thus, reliability is affected by both the accuracy of alignment and the size or proportion of missing areas in the measurement data.

The first interpolation unit 7f uses reference point cloud data to interpolate missing portions of the measurement data of the ignition coil 3, i.e., the target point cloud data, that have not been scanned. In other words, the outer surface portion of the back (lower) side of the ignition coil 3, which is hidden from view from above the engine compartment 1, is interpolated using the reference point cloud data to generate point cloud data that includes the hidden portion. The first interpolation unit 7f then converts the generated point cloud data into mesh data that constitutes a surface using a well-known conversion method.

Similarly, the second interpolation unit 7g uses the reference point cloud data to interpolate missing portions of the fuel tube 4 measurement data, i.e., the target point cloud data, that have not been scanned. In other words, the reference point cloud data is used to interpolate the outer surface portion of the back (lower) side of the fuel tube 4, which is hidden from view from above the engine compartment 1, to generate point cloud data of the fuel tube 4 including the hidden portion. The second interpolation unit 7g then converts the generated point cloud data into mesh data that constitutes a surface using a well-known conversion method.

The distance calculation unit 7h calculates the distance from each point on the surface of the ignition coil 3 to each point on the surface of the fuel tube 4 based on the mesh data of the ignition coil 3 acquired by the first interpolation unit 7f and the mesh data of the fuel tube 4 acquired by the second interpolation unit 7g. Furthermore, the distance calculation unit 7h determines the minimum distance by comparing the calculated distances with each other. Note that the distance calculation unit 7h may calculate the distance from each point on the ignition coil 3 to each point on the fuel tube 4 based on the point cloud data of the ignition coil 3 and the point cloud data of the fuel tube 4 without converting them into mesh data. Furthermore, the distance calculation unit 7h compares the minimum distance with a predetermined threshold, and if the minimum distance is less than the threshold, displays information on the display 8 that the minimum distance is less than the threshold. When presenting information to a worker that the minimum distance is less than the threshold, in addition to the above-mentioned image presentation using the display, the information may be presented by sound using an audio device such as a speaker, or by vibration using a wearable device such as a scanner held by the worker or a watch worn by the worker. In the case of presenting information by vibration, whether the minimum distance is above or below the threshold may be presented using a predetermined vibration pattern.

When the minimum distance is less than a predetermined threshold, the displacement calculation unit 7i quantitatively calculates the amount of movement required for the fuel tube 4 at the point where the minimum distance is reached and for several representative points, i.e., the amount of displacement required for the fuel tube 4 to make the minimum distance equal to or greater than the threshold, and presents the information on the display 8.

Display 8 displays the minimum distance and location between the ignition coil 3 and the fuel tube 4, along with the displacement required for the fuel tube 4. Display 8 also shows the desired placement of the fuel tube 4 within the engine compartment 1 by the area between two curves W1 and W2, shown by dashed lines in Figure 6. If the minimum distance is less than the threshold, the worker displaces the fuel tube 4 based on the displacement amount (not shown) displayed on display 8, thereby placing the fuel tube 4 within the area between curves W1 and W2. The darker area adjacent to the side of the fuel tube 4 indicates a portion of the fuel tube 4 before the worker displaces it. In this embodiment, as shown in Fig. 6, the displacement amount calculation unit 7i displays a displacement of 20 mm in a direction P away from the intake manifold 2 for one point on the straight portion 4a that extends linearly along the side of the intake manifold 2, and further displays a displacement of 10 mm in another direction Q away from the intake manifold 2 for one point on the inclined portion 4b that is inclined toward the ignition coil 3 (see Fig. 1). Note that although Fig. 6 does not show the minimum distance and the point of the minimum distance, the point of the minimum distance is located between the ignition coil 3 (see Fig. 1) and a point on the inclined portion 4b that is diagonally downward and to the left of the point at which the displacement amount in direction Q is applied.

Next, the gap inspection method of this embodiment will be explained based on the flowchart in Figure 7.

First, in step S1, the worker operates the 3D laser scanner 5 to scan a predetermined area in the engine compartment 1 from the outside, including the target components, the ignition coil 3 and fuel tube 4, to obtain point cloud data including a portion of the outer surface of each component. This scanning and generation of point cloud data progresses gradually as the scanning operation continues.

Next, in step S2, CAD data for the target components, the ignition coil 3 and fuel tube 4, and other surrounding components, along with CAD data showing their spatial positional relationships, is obtained from the database 6.

Then, in step S3, the CAD data is converted into point cloud data using a known appropriate conversion method.

Next, in step S4, the first alignment unit 7a performs rough alignment between the entire target area and the entire reference area. As described above, rough alignment is performed by aligning the point cloud data of the entire area including the ignition coil 3, fuel tube 4, and other components with the point cloud data of the entire area including the ignition coil, fuel tube, and other components in the design data stored in the database 6 using key point search and paired key point combinations.

After the rough alignment in step S4, in step S5, the aforementioned progress calculation unit 7b calculates the progress of scanning from the ratio between the number of points in the point cloud data of the reference area and the number of matching points in the point cloud data of the scanned area.

Then, in step S6, it is determined whether this progress rate exceeds a predetermined progress rate threshold (40% in this embodiment, but the threshold is not limited to this). If the progress rate is 40% or less, the process proceeds to step S7, the progress rate is displayed on the display 8, and the worker continues scanning. In other words, the process from step S1 onwards is repeated.

Also, if the progress rate exceeds 40% in step S6, the process proceeds to step S8, where the target parts, the ignition coil 3 and fuel tube 4, are extracted from the point cloud data of the measurement data and the point cloud data of the design data, respectively. The point cloud data extracted from the measurement data becomes the so-called target, and the point cloud data extracted from the design data becomes the so-called reference. The point cloud data of the target part that serves as the reference may be generated from CAD data of the part alone.

Next, in step S9, the second alignment unit 7c uses a known appropriate algorithm to perform detailed alignment of the ignition coil 3 and the fuel tube 4. Here, the fuel tube 4 is considered to be a rigid body. For example, as described above, paired points are searched for between the point cloud data of the target that has undergone rough alignment and the point cloud data of the reference, and detailed alignment is performed so that the reference approaches the target.

Next, in step S10, the aforementioned third alignment unit 7d downsamples the data of the fuel tube 4 to perform non-rigid alignment of the fuel tube 4, which is a non-rigid body. Then, in step S11, non-rigid alignment is performed taking into account the deformation of the fuel tube 4. In other words, the reference point cloud data is aligned with the target position while being deformed. In this non-rigid alignment, the nearest pair is searched for from the reference point cloud data and target point cloud data, which have been aligned assuming a rigid body as described above, and rotation, enlargement, and translation are calculated as parameters to bring them closer together.

Next, proceed to step S12 and calculate the alignment reliability for each of the ignition coil 3 and the fuel tube 4. The reliability is expressed, for example, as the ratio between the number of points in the reference point cloud data and the number of points in the target point cloud data that are included within a predetermined radius from each point in the reference point cloud data.

Then, in step S13, it is determined whether the reliability of the ignition coil 3 and the reliability of the fuel tube 4 each meet a predetermined reliability level. If both reliability levels meet the predetermined reliability level, alignment is considered complete and the process proceeds to step S14.

In step S14, the first interpolation unit 7f and the second interpolation unit 7g interpolate the unscanned portions of the target point cloud data for the ignition coil 3 and the fuel tube 4 with reference point cloud data aligned with the targets. This generates point cloud data for the ignition coil 3 and the fuel tube 4 at the positions of each target, including the unscanned portions (i.e., hidden portions).

Then, in step S15, using a well-known conversion method, the point cloud data including the unscanned parts for both the ignition coil 3 and the fuel tube 4 is converted into mesh data constituting surfaces.

Next, in step S16, the distance calculation unit 7h calculates the minimum distance between the ignition coil 3 and the fuel tube 4 based on the mesh data of the ignition coil 3 and the mesh data of the fuel tube 4. In other words, the distance between any two points on each surface is calculated, and the smallest value among these is taken as the minimum distance.

Then, in step S17, it is determined whether the minimum distance is greater than or equal to the threshold. If the minimum distance is greater than or equal to the threshold, the process proceeds to step S18, and information indicating that the minimum distance is greater than or equal to the threshold is displayed on the display 8.

Also, if the minimum threshold is less than the threshold in step S17, the process proceeds to step S19, where the displacement calculation unit 7i calculates the displacement of the fuel tube 4 required to make the minimum distance equal to or greater than the threshold. The calculated displacement is displayed on the display 8.

Also, if the reliability is less than the predetermined reliability in step S13, the process proceeds to step S20, where it is determined whether there is insufficient scanned data. If there is insufficient data, the process proceeds to step S21, where the operator is informed that scanning needs to be performed again using the 3D laser scanner 5, and the process returns to step S1.

Also, if it is determined in step S20 that there is no shortage of data, it is assumed that the reliability in step S13 was determined to be low due to excessive deformation of the fuel tube 4, and the process proceeds to step S18, where this fact is displayed on the display 8.

As described above, in this embodiment, the first interpolator 7f uses the reference point cloud data to interpolate the outer surface portion hidden behind the rigid ignition coil 3 after alignment, generating point cloud data including the hidden portion to acquire the outer shape. Similarly, the second interpolator 7g uses the reference point cloud data to interpolate the outer surface portion hidden behind the non-rigid fuel tube 4 after alignment, generating point cloud data including the hidden portion to acquire the outer shape. The outer surface shape of the non-rigid fuel tube 4, which takes deformation into account, is difficult to grasp, making it difficult to interpolate by simply applying design data. However, as in this embodiment, by aligning the outer shape and generating point cloud data including the hidden portion of the fuel tube 4 to acquire the outer shape, and using this data together with the outer shape of the ignition coil 3, the distance between any point on the ignition coil 3 and any point on the fuel tube 4 can be easily calculated.

In this embodiment, the distance calculation unit 7h calculates the minimum distance between the ignition coil 3 and the fuel tube 4. The distance calculation unit 7h then compares the minimum distance with a threshold value, and when the minimum distance is less than the threshold value, displays information on the display 8 indicating that the minimum distance is less than the threshold value. Furthermore, when the minimum distance is less than the threshold value, the displacement calculation unit 7i quantitatively calculates the location of the minimum distance and the amount of displacement of the fuel tube 4 required to make the minimum distance equal to or greater than the threshold value, and displays this information on the display 8. This allows the worker to accurately displace the fuel tube 4 toward the desired position while looking at the fuel tube 4 displayed on the display 8 when the minimum distance is less than the threshold value. Furthermore, since the fact that the minimum distance is less than the threshold value is displayed by sound or vibration, the worker can recognize that the minimum distance is less than the threshold value while continuing their work without averting their eyes.

In this embodiment, the point cloud data of the area acquired by scanning as measurement data is roughly aligned using key points with the point cloud data generated from the design data of the area including the ignition coil 3 and the fuel tube 4. The point cloud data of the ignition coil 3 based on the design data is then aligned with the point cloud data of the ignition coil 3 extracted from the measurement data, and the point cloud data of the fuel tube 4 based on the design data is then aligned with the point cloud data of the fuel tube 4 extracted as a non-rigid body from the measurement data. In other words, the positional relationship between the ignition coil 3 and the fuel tube 4 is acquired in the roughly aligned area, and then detailed alignment is performed for each of them. Therefore, the distance, i.e., the gap, can be calculated accurately based on the positional relationship between the ignition coil 3 and the fuel tube 4.

Furthermore, in this embodiment, the minimum distance between the ignition coil 3 and the fuel tube 4 is inspected during the finished vehicle inspection process. During finished vehicle inspection, the ignition coil 3 and fuel tube 4 are already assembled with various components, such as the intake manifold 2, and the ignition coil 3 is located further back than the intake manifold 2 when viewed from above the engine compartment 1, making it difficult to measure. Furthermore, the fuel tube 4 is a non-rigid body that undergoes deformation, making it more difficult to measure than a rigid body. Therefore, by using the gap inspection method of this embodiment to efficiently inspect the minimum distance between the ignition coil 3 and the fuel tube 4 during the finished vehicle inspection process, which includes the difficult-to-measure ignition coil 3 and fuel tube 4, the time required for the finished vehicle inspection process can be shortened compared to when a worker performs inspection using, for example, a ruler.

Furthermore, in this embodiment, the design minimum distance between the ignition coil 3 and the fuel tube 4 may be defined by the position of an outer surface that is not visible from the outside of at least one of the ignition coil 3 or the fuel tube 4. Even in cases where such an outer surface that is not visible from the outside of the ignition coil 3 or the fuel tube 4 is included, the minimum distance between the ignition coil 3 and the fuel tube 4 can be calculated by interpolating the above-mentioned outer surface that is not visible using the first interpolation unit 7f and the second interpolation unit 7g of the gap inspection device of this embodiment.

In this embodiment, an example of calculating the distance between the rigid ignition coil 3 and the non-rigid fuel tube 4 is disclosed, but the distance between other rigid parts and non-rigid parts located in the engine compartment 1 may also be calculated.

In addition, in this embodiment, an example of non-rigid positioning of a fuel tube 4 having a circular radial cross section has been described, but the present invention may also be applied to non-rigid positioning of piping having a radial cross section other than circular, for example, rectangular.

In addition, in this embodiment, an example of calculating the distance between rigid and non-rigid parts of an automobile is disclosed, but the distance between rigid and non-rigid parts used in devices other than automobiles may also be calculated.

In addition, in the above embodiment, an example was described in which the 3D laser scanner 5 is held and operated by a worker, but the present invention can also be applied when scanning is performed using a 3D sensor by a robot.

In addition, in this embodiment, a 3D laser scanner 5 has been described as a 3D sensor, but other types of 3D sensors, such as ToF types and triangulation types such as stereo cameras, can be widely applied.

Claims (11)

1. A gap inspection method for inspecting a distance between a first part that is rigid and a second part that is non-rigid in an assembly formed by assembling a plurality of parts, the first part and the second part, the method comprising:
scanning an area including the first part and the second part from the outside with a three-dimensional sensor to obtain measurement data including a portion of the outer surface of each part;
acquiring design data including the external shapes of the first part and the second part and the positional relationship between the two parts within the assembly;
aligning the design data of the first part as a rigid body with the position of the measurement data of the first part, and when the reliability of the alignment of the first part is satisfied, interpolating the hidden outer surface portion based on the design data of the first part, and generating an outer shape of the first part including the hidden outer surface portion;
aligning design data of the second part as a non-rigid body with the position of measurement data of the second part, and when the reliability of the alignment of the second part is satisfied, interpolating a hidden outer surface portion based on the design data of the second part, and generating an outer shape of the second part including the hidden outer surface portion;
Calculating the distance between any point on the first part and any point on the second part;
Gap inspection method. The gap inspection method according to claim 1 , further comprising calculating a minimum distance between the first component and the second component. The gap inspection method according to claim 2 , further comprising: comparing the minimum distance with a threshold; and, when the minimum distance is less than the threshold, presenting information that the minimum distance is less than the threshold. The gap inspection method according to claim 3, further comprising: when the minimum distance is less than the threshold value, calculating the location of the minimum distance and the amount of displacement of the second component required to make the minimum distance equal to or greater than the threshold value, and presenting the information. The gap inspection method according to claim 3 , further comprising presenting the information that the gap is less than the threshold value by using at least one of an image, a sound, and a vibration. After roughly aligning point cloud data generated from design data of an area including the first part and the second part with point cloud data of an area acquired by scanning as measurement data using key points,
2. The gap inspection method according to claim 1, wherein point cloud data of the first part based on design data is aligned with point cloud data of the first part extracted from measurement data, and point cloud data of the second part based on design data is aligned with point cloud data of the second part extracted from measurement data as a non-rigid body. 2. The gap inspection method according to claim 1, wherein the assembly is an automobile, the second part is a pipe arranged in an engine compartment, and the first part is a part in the engine compartment for which a minimum distance between the first part and the pipe is specified. 2. The gap inspection method according to claim 1, wherein the minimum distance between the first part and the second part is inspected during inspection of a completed automobile. 2. The gap inspection method according to claim 1, wherein the design minimum distance between the first part and the second part is defined at a position on an outer surface of at least one of the first part or the second part that is not visible from the outside. 1. A gap inspection device for inspecting a distance between a first part that is rigid and a second part that is non-rigid in an assembly formed by assembling a plurality of parts, the first part and the second part,
a three-dimensional sensor that scans an area including the first part and the second part from the outside to acquire measurement data including a portion of the outer surface of each part;
a database that stores design data including the external shapes of the first part and the second part and the positional relationship between the two parts within the assembly;
a rigid body alignment unit that aligns the design data of the first part with a position of the measurement data of the first part as a rigid body;
a non-rigid body alignment unit that aligns design data of the second part with a position of measurement data of the second part as a non-rigid body;
a reliability calculation unit that calculates a reliability of alignment for each of the first part and the second part;
a first interpolation unit that, when the degree of confidence in the alignment of the first part is satisfied, interpolates a hidden outer surface portion of the first part based on design data of the first part, and generates an outer shape of the first part including the hidden outer surface portion;
a second interpolation unit that, when the reliability of the alignment of the second part is satisfied, interpolates a hidden outer surface portion of the second part based on design data of the second part, and generates an outer shape of the second part including the hidden outer surface portion;
a distance calculation unit that calculates a distance between an arbitrary point on the first part and an arbitrary point on the second part;
A gap inspection device equipped with 1. A gap inspection method for inspecting a distance between a first part that is rigid and a second part that is non-rigid in an assembly formed by assembling a plurality of parts, the first part and the second part, the method comprising:
scanning an area including the first part and the second part from the outside with a three-dimensional sensor to obtain measurement data including a portion of the outer surface of each part;
acquiring design data including the external shapes of the first part and the second part and the positional relationship between the two parts within the assembly;
After aligning the design data of the first part as a rigid body to the position of the measurement data of the first part,
aligning the design data of the second part as a non-rigid body to the position of the measurement data of the second part;
generating an outer shape including hidden outer surface portions of the first part and the second part;
Calculating the distance between any point on the first part and any point on the second part;
Gap inspection method.