Inspection system, inspection method, and program used in inspection system

Abstract

To provide an inspection system allowing an arm tip to pass through imaging points within a predetermined error without stopping at the imaging points to be able to perform imaging at nearly each imaging point.SOLUTION: There is provided an inspection system 100 in which an imaging device C or an inspection object is provided at an arm tip 11 of an industrial robot 1, and the imaging device C is moved relative to the inspection object W to image one or more locations on a surface of the inspection object W. The system comprises: an imaging point setting unit 2 that sets, in association with passing order, a plurality of positions of the arm tip 11 when imaging is performed by the imaging device C as imaging points Pi; and a target path generation unit 4 that generates a target path RP of the arm tip 11 on the basis of the respective imaging points Pi. The target path RP includes one or more arc-shaped paths PRi, and is generated so that at least some of the imaging points Pi are arranged between a start point and an end point of the arc-shaped path PRi.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inspection system that relatively moves an imaging device with respect to an object to be inspected and images one or more locations on the surface of the object to be inspected.

Background Art

[0002] When imaging one or more locations on the surface of an object to be inspected and inspecting for scratches, defects, marks, etc. based on each captured image, the camera may be moved to a plurality of imaging points at an angle and distance at which the features of the object to be detected are likely to appear in the captured image, and the object to be inspected is imaged at each imaging point.

[0003] In such a case, in order to improve the inspection accuracy, it is required that the camera can be accurately arranged at each imaging point, and it is preferable that the time required for the movement of the camera between each imaging point is as short as possible.

[0004] For example, if a camera is provided at the tip of the arm of an industrial robot as shown in Patent Document 1 and the target path (target trajectory) of the arm tip is set to pass through each imaging point, it may seem easy to meet the above requirements at first glance.

[0005] However, when the inventor of the present application conducted an experiment using the code for setting the target path prepared in advance in such an industrial robot, the object to be inspected was imaged at a location deviated from the imaging point, and the inspection accuracy as expected could not be achieved.

[0006] Specifically, such a problem occurred when the target path was set in a zigzag path with multiple imaging points as break points in linear interpolation mode and the arm tip was set not to be stationary at each imaging point. This is presumably because feedback control based on the deviation between the target position and the detected position works for various actuators of industrial robots, and there is a delay between the actual position and the target position. With such a delay, for example, when a target path as shown in FIG. 9 is set such that a corner is formed, the actual arm tip does not turn at an angle at the corner but turns inside the vertex of the corner of the target path.

[0007] To solve such a problem, it may be considered to set the arm tip to be stationary at each imaging point. However, if so, the camera will repeat stop and go, which will increase the time required for movement and the overall inspection time. Furthermore, even if the arm tip is stationary at the imaging point, it is necessary to adjust the deceleration so that imaging can be performed without vibration at the arm tip at the imaging point or wait until the vibration subsides.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] The present invention has been made in view of the above-described problems, and provides an inspection system that can pass within a predetermined error without stopping the arm tip at the imaging point and perform imaging at substantially each imaging point.

Means for Solving the Problems

[0010] That is, the inspection system according to the present invention is an inspection system in which an imaging device or an object to be inspected is provided at the tip of an arm of an industrial robot, and the imaging device is relatively moved with respect to the object to be inspected to image one or more locations on the surface of the object to be inspected. The inspection system includes an imaging point setting unit that sets a plurality of positions of the arm tip when imaging is performed by the imaging device as imaging points and associates them with the order of passage, and a target path generation unit that generates a target path of the arm tip based on each imaging point. The target path includes one or more arc-shaped paths, and at least a part of each imaging point is arranged between the start point and the end point of the arc-shaped path, or the target path includes one or more linear paths, and at least a part of each imaging point is arranged between the start point and the end point of the linear path.

[0011] Further, the inspection method according to the present invention is an inspection method in which an imaging device or an object to be inspected is provided at the tip of an arm of an industrial robot, and the imaging device is relatively moved with respect to the object to be inspected to image one or more locations on the surface of the object to be inspected. The inspection method includes an imaging point setting step of setting a plurality of positions of the arm tip when imaging is performed by the imaging device as imaging points, and a target path generation step of generating a target path of the arm tip based on each imaging point. The target path includes one or more arc-shaped paths, and at least a part of each imaging point is arranged between the start point and the end point of the arc-shaped path, or the target path includes one or more linear paths, and at least a part of each imaging point is arranged between the start point and the end point of the linear path.

[0012] If it is such a case, since the target path is generated such that at least a part of the imaging points is arranged between the start point and the end point of the arc-shaped path or between the start point and the end point of the linear path, the imaging point or its vicinity can be passed at a constant speed without decelerating or stopping the tip of the arm in the vicinity of the imaging point. Therefore, compared with the case of using a target path set in a linear interpolation mode with a plurality of conventional imaging points themselves as target points, the position accuracy at the imaging point can be improved, and large vibrations or the like can be prevented from occurring at the tip of the arm at the imaging point. From these facts, since physical conditions closer to ideal than before can be realized when imaging the object to be inspected, the inspection accuracy can also be improved. In addition, since such an improvement in inspection accuracy can be realized without stopping the tip of the arm at the imaging point, shortening of the inspection time can also be achieved.

[0013] In addition, since the input terminal for specifying the target path provided in the industrial robot is configured to accept not only the normal linear interpolation mode but also the arc interpolation mode, the inspection system according to the present invention can be realized without performing special program modification or the like.

[0014] In order to be able to easily generate the target path, shorten the moving distance of the arm and facilitate shortening of the time required for inspection, and realize substantially the same imaging conditions at almost all imaging points, all imaging points except the first imaging point or the last imaging point may be respectively arranged between the start point and the end point of individual arc-shaped paths.

[0015] In order to strictly align the imaging conditions at each imaging point by imaging the object to be inspected while moving the tip of the arm at all imaging points, all imaging points may be respectively arranged between the start point and the end point of individual arc-shaped paths.

[0016] The target path is composed only of a plurality of arc-shaped paths, and it is possible to prevent a large change in direction from occurring at the connection points of the respective arc-shaped paths, and to arrange the imaging points at the midpoints of different arc-shaped paths. For this purpose, there are four or more imaging points, the target path is generated so as to pass through each imaging point in order, and the target path generation unit includes a temporary path generation unit that sets temporary paths set to pass through each imaging point based on a plurality of temporary path setting circles that are circles defined by three consecutive imaging points, an intermediate point setting unit that sets intermediate points between consecutive imaging points on the temporary path, and a final generation unit that generates the target path passing through each imaging point and each intermediate point based on one or more path correction circles that are circles defined by one imaging point and the two intermediate points before and after it. Note that the intermediate point is not limited to the midpoint of the arc-shaped path, but is a concept including points in the central part of the arc-shaped path.

[0017] As a specific aspect that can prevent a large change in direction from occurring at the connection point of the arc-shaped path, there is an aspect in which when three temporary path setting circles pass through one imaging point, the temporary path generation unit adopts, for the temporary path, the pair of two tangents that form a smaller angle among the three tangents defined by the respective temporary path setting circles at that imaging point.

[0018] In order to arrange the imaging points at positions farthest from the connection points of the respective arc-shaped paths and facilitate passing the tip of the arm at a constant speed at the imaging points, the intermediate point may be the midpoint of the arc between two consecutive imaging points on the temporary path.

[0019] In an existing inspection system using an industrial robot, for example, in order to be able to enjoy the same effects as the inspection system according to the present invention by updating a program, an imaging device or an object to be inspected is provided at the tip of the arm of the industrial robot, and the imaging device is relatively moved with respect to the object to be inspected to image one or more locations on the surface of the object to be inspected. A program used in an inspection system, comprising: an imaging point setting unit that sets a plurality of positions of the tip of the arm when imaging is performed by the imaging device as imaging points and associates them with the order of passage; and a target path generation unit that generates a target path of the tip of the arm based on each imaging point, and causes a computer to exhibit functions as such, wherein the target path includes one or more arc-shaped paths and is generated such that at least a part of each imaging point is arranged between the start point and the end point of the arc-shaped path, or the target path includes one or more linear paths and is generated such that at least a part of each imaging point is arranged between the start point and the end point of the linear path. The program for the inspection system characterized by this may be used.

[0020] Note that the program for the inspection system may be distributed electronically or may be recorded on a program recording medium such as a CD, DVD, or flash memory.

Effect of the Invention

[0021] Thus, in the inspection system according to the present invention, since the target path is generated such that the imaging points are arranged between the start point and the end point on the arc-shaped path, it is possible to pass through the imaging points or their vicinity while moving the tip of the arm at a constant speed. For this reason, while minimizing the time during which the tip of the arm is stationary or decelerated and shortening the time required for inspection, the object to be inspected can be imaged at the actually assumed imaging points, so that the inspection accuracy can be improved compared to the case where a target path generated in a linear interpolation mode is used.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

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Figure 8

Figure 9

Mode for Carrying Out the Invention

[0023] The inspection system 100 in one embodiment of the present invention will be described with reference to each figure.

[0024] The inspection system 100 of the present embodiment is used to perform an appearance inspection by detecting scratches, defects, attached marks, characters, etc. of an object to be inspected W such as a product based on a captured image. Specifically, as shown in FIG. 1, the inspection system 100 includes an industrial robot 1 having a camera C, which is an imaging device, provided at the tip 11 of the arm, and a control arithmetic mechanism COM that inputs commands to the industrial robot 1 and controls its operation. The inspection system 100 is configured to relatively move the camera C by the industrial robot 1 with respect to the object to be inspected W fixed at a predetermined position, and capture a plurality of locations on the surface of the object to be inspected W. For example, the object to be inspected W has a cylindrical shape, and the camera C is moved in the circumferential direction and the axial direction with respect to the object to be inspected W by the industrial robot 1 and captures images at a plurality of imaging points.

[0025] Each part will be described in detail.

[0026] The industrial robot 1 is controlled so as to be a command for inputting the position and orientation of the arm tip 11 (end). The arm tip 11 is configured to be controllable with a total of six degrees of freedom, three degrees of freedom with respect to position and three degrees of freedom with respect to orientation. For example, the industrial robot 1 can use a vertical articulated robot. Note that the industrial robot 1 may be a horizontal articulated robot (scalar robot), a parallel link robot, an orthogonal robot, etc., and the arm tip 11 may perform only position control, or may have at least two degrees of freedom in position control. This industrial robot 1 receives a code in which at least one set of position coordinates to be routed or arranged at the arm tip 11 as an operation command and a moving speed between each position coordinate is included, and internally generates position command data configured as time-series data from the code. Then, based on the deviation between the position information at each time indicated by the position command data and the actually measured position of the arm tip 11 detected by the detector provided in the industrial robot 1, various actuators are controlled by at least position feedback control. As the code, a G code defined by JIS or other codes independently prepared by various manufacturers of the industrial robot 1 can be used. At least the code can specify two position coordinates, a moving speed, and whether to interpolate between the two points by linear interpolation or circular interpolation. When it is specified to move between a plurality of target position coordinates by linear interpolation, the arm tip 11 moves in a linear motion along a linear path. On the other hand, when it is specified to move between a plurality of target position coordinates by circular interpolation, the arm tip 11 moves in a circular motion along a circular path.

[0027] The control arithmetic mechanism COM is a so-called computer including, for example, a CPU, a memory, various input / output devices, an A / D converter, a D / A converter, etc. The inspection system 100 program stored in the memory is executed, and by cooperating with various devices, it functions as at least the imaging point setting unit 2, the moving speed setting unit 3, the target path generation unit 4, and the shutter control unit 5.

[0028] Each part will be described.

[0029] The imaging point setting unit 2 receives, as user input, the imaging point, which is the position of the arm tip 11 when imaging is performed by the camera C. In this embodiment, at least four or more imaging points are specified. As a method for specifying the imaging points, various methods can be used, such as specification by absolute coordinates based on the body position of the industrial robot 1, specification by relative coordinates based on the arm tip 11, and teaching by moving the arm tip 11 of the industrial robot 1 to the position where imaging is actually desired and then teaching. A plurality of imaging points are received by the various methods as described above, and as each imaging point, a position coordinate and the order in which the arm tip 11 passes through each imaging point are associated and set. In the following description, each imaging point is denoted as Pi with the subscript i representing the order in which the arm tip 11 passes through. Also, for the imaging point Pi, the posture of the arm tip 11 (the posture of the camera C) at each imaging point Pi may also be associated.

[0030] The movement speed setting unit 3 receives, as user input, information regarding the movement speed of the arm tip 11 between the specified imaging points Pi and whether to stop or continue moving without stopping at the imaging point Pi.

[0031] The target path generation unit 4 generates a target path for moving the arm tip 11 based on the received plurality of imaging points Pi and the movement speed, and inputs, as a movement command, a code in a format readable by the industrial robot 1 to the industrial robot 1. In this embodiment, unless otherwise specified, the target path generation unit 4 generates the target path as a plurality of arc-shaped paths RPi, and arranges the imaging point Pi between the start point and the end point of each arc-shaped path RPi. In other words, the imaging point Pi is not arranged at the connection point of the plurality of arc-shaped paths RPi that constitute the target path, but at other points.

[0032] More specifically, the target path generation unit 4 includes a temporary path generation unit 41 that generates a temporary path TP based on a plurality of imaging points Pi, an intermediate point setting unit 42 that sets intermediate points between the respective imaging points Pi based on the temporary path TP, and a final generation unit 43 that generates a target path based on the respective imaging points Pi and the respective intermediate points. In the following description, each intermediate point is denoted as Mi with a subscript indicating the order in which the arm tip 11 passes through. That is, as shown in the flowchart of FIG. 2, the target path generation unit 4 first calculates a plurality of temporary path setting circles based on the set plurality of imaging points Pi (step S1). Next, based on each temporary path setting circle, intermediate points Mi arranged between the respective imaging points Pi on the temporary path are set (step S2). Finally, a target path is generated based on a path correction circle defined by two intermediate points Mi and the imaging point Pi therebetween (step S3). By such a procedure, the target path generation unit 4 generates a target path RP in which all the imaging points Pi except the first imaging point P1 and the last imaging point PN are arranged at the respective intermediate points Mi in the arc-shaped path RPi in the present embodiment.

[0033] The shutter control unit 5 acquires information regarding the target path RP from the target path generation unit 4, and controls the timing of closing the shutter of the camera C, for example, based on the scheduled time when the arm tip 11 reaches the imaging point Pi. Note that the shutter control unit 5 may control the shutter timing based on the position of the arm tip 11 obtained based on the measurement values output from various detectors of the industrial robot 1.

[0034] Next, the configuration and operation details of each part constituting the target path generation unit 4 will be described with reference to FIGS. 3 to 6. Hereinafter, for simplicity of explanation, it is assumed that six imaging points Pi are set, but even if a larger number of imaging points Pi are set, the target path can be set by the same method. Further, in FIGS. 3 to 6, each imaging point Pi is arranged on a two-dimensional plane, but it can be similarly extended even in a three-dimensional space. In addition, although the posture at each imaging point Pi is omitted, commands can be generated by the same method for posture control.

[0035] First, as shown in FIG. 3, the temporary path generation unit 41 calculates four temporary path setting circles C123, C234, C345, and C456 defined by three consecutive sets of a plurality of imaging points P1 to P6. Next, based on each of the temporary path setting circles C123, C234, C345, and C456, the temporary path generation unit 41 determines temporary path elements that are arcs connecting between the respective imaging points P1 to P6 and constitute a part of the temporary path. Since there are only the temporary path setting circles C123 and C456 between the imaging points P1 and P2 and between the imaging points P5 and P6, these partial arcs are adopted as the temporary path elements TP1 and TP5, respectively.

[0036] Next, the temporary path generation unit 41 determines an arc connecting the imaging points P2 and P3. As shown in FIG. 3, two temporary path setting circles C123 or C234 can be defined between the imaging points P2 and P3. In such a case, the temporary path setting circle is selected so that the arc connecting between the previous imaging points P1 and P2 and the arc connecting between the imaging points P2 and P3 are connected as smoothly as possible at the imaging point P2 that is the connection point. That is, since the imaging points P1 and P2 are connected by an arc by the temporary path setting circle C123, by similarly adopting the temporary path setting circle C123 as the temporary path element TP2 between the imaging points P2 and P3, the tangent line at the imaging point P2 can be continuously changed and connected most smoothly.

[0037] Next, with reference to FIGS. 3 and 4, how the temporary path generation unit 41 sets temporary path elements when three temporary path setting circles C123, C234, and C345 intersect at a single point, such as imaging point P3, will be described. Similar to what has been described above, the temporary path generation unit 41 sets arcs such that the temporary path elements TP2 and TP3 are connected as smoothly as possible at the imaging point P3, which is the connection point of each arc. That is, when three temporary path setting circles C123, C234, and C345 pass through a single imaging point P3, the temporary path generation unit 41 is configured to adopt, as the temporary path element TP3, the pair of tangents that form a smaller angle among the three pairs of tangents defined by the respective temporary path setting circles C123, C234, and C345 at the imaging point P3. As shown in the enlarged view of FIG. 4, since the temporary path element TP2 connecting the imaging points P2 and P3 is a part of the temporary path setting circle C123, the temporary path element TP3 is determined by the magnitudes of the angles formed by the tangents of the temporary path setting circles C234 and C345 on the imaging point P3 with respect to the tangent of the temporary path setting circle C123 on the imaging point P3. As is clear from FIG. 4, in this example, the angle formed by the tangent of the temporary path setting circle C234 (shown as a solid line) and the tangent of the temporary path setting circle C123 (shown as a two-dot chain line) is smaller than the angle formed by the tangent of the temporary path setting circle C345 (shown as a dotted line) and the tangent of the temporary path setting circle C123 (shown as a two-dot chain line). Therefore, the temporary path generation unit 41 adopts the temporary path setting circle C234 connecting between the imaging points P3 and P4 as the temporary path element TP3.

[0038] Regarding the imaging point P4, based on the three temporary path setting circles C234, C345, and C456, the temporary path element TP4 is set in the same procedure as described above.

[0039] By repeating the comparison of the angles formed by the tangents in this way, finally, the temporary path generation unit 41 generates a temporary path TP in which the temporary path elements TP1 to TP5 are connected at the imaging points P2 to P5, respectively, to form one curve as shown in FIG. 5. In the temporary path TP, since each imaging point P1 to P6 is arranged at the end point of the arc, if the industrial robot 1 is operated using the temporary path TP as it is, for example, at the imaging point P3, the moving direction changes, and imaging cannot be performed while the arm tip 11 is moving at a constant speed. Therefore, for the imaging points P2 to P5 excluding the imaging points P1 and P6 which are the start point and the end point, the temporary path TP is corrected and arranged between the start point and the end point of the arc to be the target path.

[0040] Specifically, when the temporary path TP is generated by the temporary path setting unit, the intermediate point setting unit 42 sets intermediate points M1 to M5 between the imaging points P1 to P6 on the temporary path elements TP1 to TP5, each of which is a partial arc, as shown in FIG. 6. In the present embodiment, the intermediate points M1 to M5 are the midpoints of the temporary path elements TP1 to TP5, respectively, but any point other than the end points of the temporary path elements TP1 to TP5 may be used. Preferably, after the arm tip 11 passes through the intermediate points M1 to M5, the intermediate points M1 to M5 are separated by a predetermined distance so that the moving speed of the arm tip 11 stabilizes at the set speed at the imaging points P1 to P6.

[0041] Furthermore, as shown in FIG. 7, the final generation unit 43 generates a target path passing through the imaging points P1 to P6 and the intermediate points M1 to M5 based on a plurality of path correction circles CA12, CA23, CA34, CA45, which are circles defined by the imaging points P2 to P5 and the two intermediate points M1 to M5 before and after. That is, the final generation unit 43 first calculates the path correction circles CA12, CA23, CA34, CA45 with two consecutive intermediate points as endpoints and passing through the imaging points therebetween. Next, the final generation unit 43 generates a target path by connecting the end of the temporary path TP and a part of each of the path correction circles CA12, CA23, CA34, CA45. Specifically, for the arc-shaped path RP1 connecting the imaging point P1 as the starting point and the intermediate point M1, a part of the temporary path element TP1 is adopted. Also, for the arc-shaped path PR6 connecting the intermediate point M5 and the imaging point P6 as the end point, a part of the temporary path element TP5 is adopted. Also, for the imaging points P2 to P5, a part of the corresponding path correction circles CA12, CA23, CA34, CA45 is adopted. Also, the intermediate points M1 to M5 are connection points of the respective arc-shaped paths RP6. In this way, for the imaging points P2 to P5 on the target path, they are arranged on the midpoints of the arc-shaped paths PR2 to PR5. Then, the final generation unit 43 inputs the code corresponding to the generated target path to the industrial robot 1.

[0042] In the inspection system 100 of this embodiment configured as described above, while the arm tip 11 of the industrial robot 1 passes through each of the imaging points P1 to P6, it can pass through the imaging points P2 to P5 in a circular motion. As described above, the target path is generated by the arc-shaped paths PR1 to PR6, and since the imaging points P2 to P5 are set on the midpoints of the arc-shaped paths PR2 to PR5, compared with the case where the target path is generated by linear interpolation, the coordinates of the imaging points P2 to P5 can be passed through almost accurately even while moving the arm tip 11. Furthermore, since the shutter control unit 5 synchronizes and closes the shutter at the timing when the arm tip 11 reaches each of the imaging points P1 to P6, while moving the camera C at high speed, the surface of the object to be inspected W can be imaged at each of the imaging points P1 to P6, which is a position suitable for performing the inspection. As a result, it becomes possible to accurately and quickly perform the inspection of the object to be inspected W.

[0043] Other embodiments will be described.

[0044] In the above embodiment, the target path was composed only of an arc-shaped path. However, for example, when the distance between two imaging points is large, the tip of the arm may perform circular motion in the vicinity of the imaging point, and perform linear motion in other parts, so that the time required for inspection can be shortened. In such a case, by setting the connection point between the linear motion and the circular motion at a position sufficiently far from the imaging point, it is possible to prevent displacement or vibration of the arm tip due to a change in the motion direction from occurring at the imaging point.

[0045] In the above embodiment, the tip of the arm was stationary at the imaging point of the start point and the imaging point of the end point. However, imaging may be performed in a state where the arm tip is rotating in the same manner as other imaging points, so that the imaging conditions and inspection conditions can be made uniform. In such a case, for example, an intermediate point adjacent to the imaging points of the start point and the end point is extrapolated to a position that is line-symmetric with respect to each imaging point, and the target path may be set so as to connect the extrapolated intermediate point and the imaging point that becomes the start point or the end point with an arc-shaped path.

[0046] When setting the target path, it is not always necessary to set a temporary path. For example, the midpoint between adjacent imaging points may be calculated, and an arc-shaped path may be generated at the two midpoints and one imaging point serving as a passing point. In such a method, the rate of change of the tangent of the arc-shaped path becomes large at the midpoint, and there is a possibility of generating a knot. However, since the imaging point is arranged in the middle of the arc-shaped path, a state close to the above embodiment can be realized for the imaging state.

[0047] In the above embodiment, an imaging device is provided at the tip of the arm, and the object to be inspected is fixed. Conversely, the object to be inspected may be provided at the tip of the arm, and the camera may be fixed. That is, the object to be inspected and the imaging device may perform relative motion. In addition, the imaging device may include not only a camera but also a mechanism for illuminating the object to be inspected, such as a flash or a ring light. Further, the imaging device may not include an illumination mechanism, and the illumination mechanism may be fixed together with the object to be inspected.

[0048] The target path may be generated only in the linear interpolation mode. That is, instead of generating a zigzag target path by the linear interpolation mode with each imaging point as a target point as in the conventional art, in the present invention, for each imaging point or a part thereof, it is arranged at an intermediate point of a linear path. Here, the intermediate point is not limited to the midpoint of the linear path, and can be defined as any point other than each end point of the linear path. Further, the intermediate point may be defined as a point within a range of a predetermined ratio of the length of the linear path with reference to the midpoint of the linear path. Specifically, it may be defined as a point within 30% of the total length of the linear path, within 20% of the total length, within 10% of the total length, or within 5% of the total length with reference to the midpoint. In the target path composed only of linear paths, in order to set each imaging point not as an end point but as an intermediate point of the linear path, the same method as in the above embodiment may be used. For example, based on each imaging point, a temporary path composed of a plurality of linear paths with each imaging point as an end point may be set by a conventional method, and a target path in which each imaging point is arranged at an intermediate point of the linear path may be set from the temporary path.

[0049] As a more specific example, a modified embodiment in which each imaging point is arranged at the midpoint of a linear path to generate a target path on a zigzag will be described with reference to FIG. 8. In this example, for simplicity, consider the case where only imaging points P1, P2, and P3 are given. Also, the same reference numerals will be given to the members corresponding to the inspection system of the above embodiment that generates the target path with a plurality of arc-shaped paths.

[0050] As shown in FIG. 8(a), the temporary path generation unit 41 generates a temporary path composed of two linear paths L1 and L2 with the imaging points P1, P2, and P3 as end points based on the imaging points P1, P2, and P3. This temporary path is the same as the path obtained by the conventional linear interpolation mode.

[0051] As shown in FIG. 8(b), the intermediate point setting unit 42 calculates the midpoints M1 and M2 of the respective linear paths L1 and L2, and calculates symmetric points MX1 and MX2 that are symmetric to the midpoints M1 and M2 on the virtual straight lines obtained by extending the proximal ends of the respective linear paths L1 and L2.

[0052] As shown in FIG. 8(c), the final generation unit 43 sets a supplementary straight linear path AL1 having the symmetric point MX1 and the midpoint M1 as endpoints. It is obvious that such a supplementary straight linear path AL1 includes the imaging point P1 at the midpoint. Next, the final generation unit 43 sets a running straight line HL1 having the midpoint M1 and the symmetric point MX2 as endpoints. None of the imaging points P1, P2, and P3 are included on the running straight line HL. Further, the final generation unit 43 sets a supplementary straight linear path AL2 having the symmetric point MX2 and the midpoint M2 as endpoints. The midpoint of this supplementary straight linear path AL2 is where the imaging point P2 is arranged. Finally, the final generation unit 43 sets a supplementary straight linear path AL3 that is a half straight line passing through the midpoint M2 and the imaging point P3 and whose terminal side extends beyond the imaging point P3. That is, it is set so that stopping, deceleration, etc. do not occur at the imaging point P3. That is, a zigzag target path composed of the supplementary straight linear paths AL1, AL2, AL3 and the running straight line HL1 is finally generated.

[0053] Even for such a target path, since each imaging point P1, P2, P3 is not set at the endpoint of the linear path, the arm tip 11 can pass through each imaging point P1, P2, P3 at a constant speed. Therefore, it is possible to surely pass through the imaging points P1, P2, P3 in the same manner as the target path of the above-described embodiment formed by the arc-shaped path, and the inspection accuracy can be improved. Note that the imaging point does not have to be the midpoint on the straight linear path, and the position may be appropriately set so that the imaging point can be passed at a constant speed. For example, the positions of the symmetric point and the imaging point may be set to be a fraction of the distance between the imaging point and the midpoint.

[0054] In addition, various modifications of the embodiments and combinations of parts of the respective embodiments may be made as long as they do not depart from the spirit of the present invention.

Explanation of Signs

[0055] 100: Inspection system 1: Industrial robot 11: Arm tip COM: Control arithmetic unit 2: Imaging point setting unit 3: Movement speed setting unit 4: Target path generation unit 5: Shutter control unit 41: Temporary path generation unit 42: Intermediate point setting unit 43: Final generation unit C: Camera W: Object to be inspected

Claims

1. An inspection system that provides an imaging device or an object to be inspected at the tip of an arm of an industrial robot, relatively moves the imaging device with respect to the object to be inspected, and images one or more locations on the surface of the object to be inspected, an imaging point setting unit that sets a plurality of imaging points associated with the order of passage, with the position of the arm tip when imaging is performed by the imaging device as an imaging point; a target path generation unit that generates a target path of the arm tip based on each imaging point, wherein the target path includes one or more arc-shaped paths and is generated such that at least a part of each imaging point is disposed between the start point and the end point of the arc-shaped path, or the target path includes one or more linear paths and is generated such that at least a part of each imaging point is disposed between the start point and the end point of the linear path. The inspection system is characterized by this.

2. The inspection system according to claim 1, wherein all imaging points except the first imaging point or the last imaging point are respectively disposed between the start point and the end point of an individual arc-shaped path.

3. The inspection system according to claim 1, wherein all imaging points are respectively disposed between the start point and the end point of an individual arc-shaped path.

4. There are four or more imaging points, and the target path is generated so as to pass through each imaging point in order, the target path generation unit includes a temporary path generation unit that sets a temporary path set to pass through each imaging point based on a plurality of temporary path setting circles that are circles defined by three consecutive imaging points; an intermediate point setting unit that sets intermediate points between consecutive imaging points on the temporary path; a final generation unit that generates the target path passing through each imaging point and each intermediate point based on one or more path correction circles that are circles defined by an imaging point and the two intermediate points before and after it. The inspection system according to claim 1.

5. The inspection system according to claim 4, wherein when three temporary path setting circles pass through one imaging point, the temporary path generation unit is configured to adopt, for the temporary path, the pair with the smaller angle formed by two pairs among the three tangents defined by each temporary path setting circle at that imaging point.

6. The inspection system according to claim 4, wherein the intermediate point is the midpoint of an arc between two consecutive imaging points on the temporary path.

7. A inspection method in which an imaging device or an object to be inspected is provided at the tip of an arm of an industrial robot, and the imaging device is relatively moved with respect to the object to be inspected to image one or more locations on the surface of the object to be inspected, an imaging point setting step of setting a plurality of positions of the arm tip when imaging is performed by the imaging device as imaging points; a target path generation step of generating a target path of the arm tip based on each imaging point, and comprising: the target path includes one or more arc-shaped paths, and at least a part of each imaging point is arranged between the start point and the end point of the arc-shaped path, or the target path includes one or more linear paths, and at least a part of each imaging point is arranged between the start point and the end point of the linear path. The inspection method is characterized in that it is generated as described above.

8. A program used in an inspection system in which an imaging device or an object to be inspected is provided at the tip of an arm of an industrial robot, and the imaging device is relatively moved with respect to the object to be inspected to image one or more locations on the surface of the object to be inspected, an imaging point setting unit that sets a plurality of positions of the arm tip when imaging is performed by the imaging device as imaging points, and associates them with the order of passage; a target path generation unit that generates a target path of the arm tip based on each imaging point, and causes a computer to exhibit functions as: the target path includes one or more arc-shaped paths, and at least a part of each imaging point is arranged between the start point and the end point of the arc-shaped path, or the target path includes one or more linear paths, and at least a part of each imaging point is arranged between the start point and the end point of the linear path. The program for an inspection system is characterized in that it is generated as described above.

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