Multi-axis linkage visual inspection equipment and calibration method thereof

Abstract

The present application relates to the field of visual detection equipment calibration, in particular to a multi-axis linkage visual detection equipment and a calibration method thereof. In view of the technical defects in the prior art, the present application provides a multi-axis linkage visual detection equipment, which comprises an equipment main body, the equipment main body comprising a tool assembly for placing a detection object and having a first rotation direction; the present application can better cooperate with the movement or rotation of the tool assembly and the visual acquisition assembly in each direction to adjust the relative position between the detection object and the visual detection assembly, thereby achieving a better detection image acquisition effect; the present application obtains the compensation value of each station compared with the first station when the station rotates at different angles in the forward and reverse directions, so that the detection personnel can use the compensation value as a reference to offset the deviation between different stations through program setting, thereby ensuring the consistent and stable performance of the entire detection process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of visual inspection equipment calibration, in particular, to a multi-axis linkage visual inspection equipment and a calibration method thereof. BACKGROUND

[0002] With the development of economy, various products with high appearance requirements such as electronic product middle frames have entered the market. Since whether the appearance of these products has defects directly affects their normal use, before these products are put into use, visual inspection of their appearance is needed to screen out defective products with appearance defects. Since the yield of these products is increasing, the demand for visual inspection equipment is also increasing.

[0003] Traditional manual detection has been gradually replaced by visual inspection equipment due to low detection efficiency and low detection rate of defective products. The existing visual inspection equipment usually adopts a multi-axis linkage mode to adjust the posture of the detection object or the visual equipment, so as to cover the key detection parts of the detection object. However, since the multi-axis linkage mode requires a large number of devices and circuit arrangements to realize, the devices of the existing multi-axis linkage equipment are complex in device and circuit arrangement, which leads to an overall structure that is not compact and reasonable, and is not convenient to build. On the other hand, the structure and wiring problem of the existing equipment directly leads to the problem that the visual inspection method suitable for the equipment is not efficient enough, and there is too much invalid motion in the whole detection process, which easily affects the stability of the detection object during the detection process, and also makes the whole detection process not fine enough and prone to errors during the detection process. Therefore, a detection equipment with more reasonable device arrangement and a detection method suitable for it with more stable and efficient operation are lacking in the market.

[0004] At the same time, since the demand for product detection is large, the existing visual inspection equipment mostly needs multiple stations to be synchronized to detect multiple detection objects at the same time to greatly improve the detection efficiency. However, since there are differences in the rotation zero point positions of each station during equipment installation and debugging, and since there are errors such as flatness in the fixing of the detection object and the processing of the visual inspection installation parts, there are differences in the perpendicularity during installation, and the aforementioned errors will be accumulated. Therefore, there are differences in the consistency and synchronization of work between each station, which may affect the normal operation of the whole detection work.

[0005] There is little research on how to calibrate the consistency of multi-station synchronous work stably and at low cost in the prior art. Meanwhile, due to the complex arrangement structure of the multi-axis equipment, the auxiliary calibration equipment commonly used in the prior art, such as a laser interferometer, often cannot be applied due to the light path being blocked in the multi-axis equipment. Therefore, a new type of multi-axis linkage equipment and a low-cost calibration method suitable for application are problems to be solved in the current visual detection field. SUMMARY

[0006] In view of the technical defects in the prior art, the present application provides a multi-axis linkage visual detection equipment, which comprises an equipment main body, the equipment main body comprising a tooling assembly for placing a detection object and having a first rotation direction; a calibration block can be placed at the tooling assembly, and a rectangular reference block is formed at the calibration block;

[0007] The tooling assembly is provided with a plurality of and sequentially forms a first station, a second station and the remaining stations arranged in this order; the tooling assembly at each station is driven by a side DD motor to realize rotation in the first rotation direction;

[0008] The equipment main body further comprises a visual acquisition assembly having a second movement direction, the rotation axis of the tooling assembly in the first rotation direction being orthogonal to the second movement direction of the visual acquisition assembly; the visual acquisition assembly is provided with a plurality of and corresponds to the tooling assembly one by one.

[0009] The present application can better cooperate with the movement or rotation of the tooling assembly and the visual acquisition assembly in each direction to adjust the relative position between the detection object and the visual detection assembly, thereby realizing better detection image acquisition effect, and further ensuring the accuracy of the detection result analyzed and detected from the acquired image.

[0010] As a preferred, the tooling assembly can be located in the detection area formed at the visual acquisition assembly.

[0011] As a preferred, the side DD motor controls the rotation angle through an external control signal.

[0012] As a preferred, the calibration block is consistent in shape and size with the detection object.

[0013] As a preferred, the calibration block can be adsorbed and fixed by the positioning suction cup at each station.

[0014] The present application also provides that when the foregoing multi-axis linkage visual detection equipment is used with the visual acquisition assembly, calibration is performed by the following steps; step S1, placing and fixing the calibration block at the first station;

[0015] Step S2, the vision acquisition component corresponding to the first station is adjusted along the Z axis to make the image clear, then the first station is imaged and an image i0 of the zero position of the station motor at the first station is obtained;

[0016] Step S3, the side DD motor is rotated forward by θ angle, driving the tooling components at each station to rotate accordingly, n*θ=180°; the vision acquisition component is imaged and processed; and an image i1 of the first station when the side DD motor is at θ angle is obtained and compared with i0 to obtain a comparison result;

[0017] Step S4, according to the step in S3, the side DD motor is rotated to (n-1)*θ position in sequence, and images i2 to i (n-1) are obtained, and each of the images is compared with the image i0 to obtain a comparison result;

[0018] Step S5, the side DD motor returns to the original position;

[0019] Step S6, steps S2 to S4 are repeated N times to obtain the comparison results of each image relative to i0;

[0020] Step S7, an average value of the comparison results is taken as a reference value of the first station in the positive direction at each (n-1)*θ angle;

[0021] Step S8, the side DD motor is rotated in the reverse direction according to steps S3 to S7 to obtain a reference value of the first station in the reverse direction;

[0022] Step S9, the side DD motor is reset, and the camera corresponding to the first station is raised along the Z axis to reset; the calibration block is loosened and removed, and placed on the second station;

[0023] Step S10, the camera on the second station obtains the reference values of the second station in the positive direction and the reverse direction at each (n-1)*θ angle according to steps S2 to S8;

[0024] Step S11, the reference values of the remaining stations in the positive direction and the reverse direction at each (n-1)*θ angle are completed according to steps S39 to S310;

[0025] Step S12, taking the first station as a reference, compensation values of the remaining stations in the positive direction and the reverse direction at each (n-1)*θ angle are calculated and the calibration of the consistency of each station is completed through the compensation values.

[0026] As a preferred, in step S3 and step S4, the comparison quantity is i1, i2 to i (n-1) , and the length change d 11 , d 21 , to d (n-1)1 .

[0027] As preferred, the reference value in step S7 and step S8 is selected as the length value of the side l, and the calculation formula of the positive direction reference value is The calculation formula of the reverse direction reference value is

[0028] As preferred, the compensation value calculation formula of the positive direction in step S12 is d mz = d mz(n-1) -d 1z(n-1) , and the compensation value calculation formula of the reverse direction is d mf = d mf(n-1) -d 1f(n-1) .

[0029] As preferred, the positive direction compensation value and the reverse direction compensation value obtained in the foregoing steps are used to control and adjust the rotation angle of the corresponding motor to realize the consistency of multiple stations.

[0030] Specifically, the calibration method in the application obtains the reference value and the compensation value by taking the length change of the side l as the comparison quantity, on the one hand, since the projection length l' = l*cosθ of the reference block side l in the camera imaging plane in the calibration block main body during the rotation of the side DD motor, that is, there is a certain function corresponding relationship between the projection length and the rotation angle, so that the length change of the side l is used as the calibration reference of the rotation angle, which is stable and reliable and can preferably ensure the calibration accuracy; on the other hand, the length of l in the image collected by the camera can be clearly identified, so that the situation of increasing the calibration difficulty due to the difficulty in identifying the selected reference quantity can be preferably avoided.

[0031] Understandably, by obtaining the compensation value of each station at different angles of rotation in the positive and reverse directions compared with the first station, the detection personnel can use the compensation value as a reference to offset the deviation between different stations through program setting, thereby ensuring the consistent and stable performance of the entire detection process.

[0032] In addition, it is worth noting that, compared with the commonly used laser interferometer in the prior art, the calibration method in the application does not need to adjust the light, has high speed, small device volume, stable and convenient calibration process, and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the equipment main body in embodiment 1;

[0034] Figure 2 It is a structural schematic diagram of the visual acquisition assembly in embodiment 1;

[0035] Figure 3 It is a structural schematic diagram of the three-axis platform in embodiment 1;

[0036] Figure 4For Figure 3 Structure diagram of the middle horizontal platform;

[0037] Figure 5 For Figure 3 Structure diagram of the middle mounting frame;

[0038] Figure 6 For Figure 5 Structure diagram of the middle mobile setting plate;

[0039] Figure 7 Structure diagram of the two-axis rotating device in Embodiment 2;

[0040] Figure 8 For Figure 7 Structure diagram of the middle mounting plate;

[0041] Figure 9 For Figure 7 Structure diagram of the first-axis rotating plate and the second-axis rotating station in Embodiment 3;

[0042] Figure 10 For Figure 9 Structure diagram of the second-axis rotating station in Embodiment 3;

[0043] Figure 11 For Figure 9 Structure diagram of the second-axis rotating station in Embodiment 3 from another perspective;

[0044] Figure 12 For Figure 10 Structure diagram of the limiting plate in Embodiment 3;

[0045] Figure 13 Structure diagram of the main body of the calibration block in Embodiment 3;

[0046] Figure 14 Structure diagram of the main body of the calibration block in Embodiment 3 from another perspective;

[0047] Figure 15 Structure diagram of the middle horizontal platform; DETAILED DESCRIPTION

[0048] For further understanding of the present application, the application will be described in detail with reference to the drawings and embodiments. It should be understood that the embodiments are only used to explain the present application but not to limit the present application.

[0049] Embodiment 1

[0050] In combination with Figures 1-6The embodiment provides a multi-axis linkage visual detection device, which comprises a device main body 100, a space coordinate system of XYZ axes is established in a space where the device main body 100 is located, a Z axis is formed along a vertical direction, and an X axis and a Y axis are formed along a horizontal plane and are perpendicular to each other; the device main body 100 comprises a tool assembly 140 used for placing a detection object and a visual acquisition assembly 120 used for acquiring a detection image of the detection object, a detection area is formed at the visual acquisition assembly 120, and the tool assembly 140 can be located at the detection area.

[0051] The tool assembly 140 has a first rotation direction and a second rotation direction which are independent of each other and are used for jointly realizing posture adjustment of the detection object; rotation axes of the first rotation direction and the second rotation direction of the tool assembly 140 are perpendicular to each other.

[0052] It can be understood that the rotation axes which are perpendicular to each other can be conveniently built on one hand, and on the other hand, can be convenient for setting and calculation of position and posture adjustment.

[0053] In the embodiment, the visual acquisition assembly 120 has a first movement direction and a second movement direction which are independent of each other, the first movement direction and the second movement direction of the visual acquisition assembly 120 are perpendicular to each other, and the tool assembly 140 has a third movement direction; the first movement direction, the second movement direction and the third movement direction are used for jointly realizing adjustment of relative spatial positions between the visual acquisition assembly 120 and the detection object.

[0054] A rotation axis of the tool assembly 140 in the second rotation direction is consistent with the second movement direction of the visual acquisition assembly 120; and the third movement direction of the tool assembly 140 is further used for realizing movement of the tool assembly 140 and the detection object placed in the tool assembly 140 between a feeding area and the detection area.

[0055] In the embodiment, the first movement direction, the second movement direction and the third movement direction are respectively the X axis direction, the Z axis direction and the Y axis direction in the space coordinate system.

[0056] Specifically, movement or rotation of the tool assembly 140 and the visual acquisition assembly 120 in various directions can be preferably cooperated to adjust relative positions between the detection object and the visual detection assembly, so that a better detection image acquisition effect is realized, and then detection result accuracy analyzed from the acquired image is ensured.

[0057] Specifically, the equipment body 100 comprises a three-axis platform 130 and a mobile loading mechanism 110 mounted on one side of the three-axis platform 130, the mobile loading mechanism 110 comprising a two-axis rotating device 710 arranged with a tool assembly 140; the three-axis platform 130 comprises a platform body, the platform body comprising a horizontal platform 131 arranged horizontally and a mounting frame 132 arranged vertically on the horizontal platform 131; the mobile loading mechanism 110 and the horizontal platform 131 of the three-axis platform 130 are movably matched to realize the movement of the tool assembly 140 in the third movement direction.

[0058] The mounting frame 132 of the platform body is movably arranged with a mobile mounting plate 510 in the first movement direction, and the visual acquisition assembly 120 is movably arranged on the mobile mounting plate 510 in the second movement direction. The movable arrangement between the mobile mounting plate 510 and the mounting frame 132 can be realized by a linear motor and a guide rail; the movable arrangement between the visual acquisition assembly 120 and the mobile mounting plate 510 can be realized by a screw module.

[0059] Specifically, the equipment body 100 capable of five-axis linkage can be built by mounting the mobile loading mechanism 110, i.e. the two-axis rotating device 710, on the three-axis platform 130 with three-axis linkage function; the visual inspection equipment capable of five-axis linkage function can preferably meet the detection requirements of the inspected workpiece. Moreover, in the embodiment, the overall structure of the equipment body 100 built is compact and the space utilization is efficient, and the three-axis platform 130 and the two-axis rotating device 710 will not cause excessive invalid space after being combined and built, so that the equipment body 100 will not occupy too large a use space in the working area, thereby preferably reducing the influence on the workers and other equipment in the working area.

[0060] Embodiment 2

[0061] In combination Figures 7-12 , the embodiment provides the two-axis rotating device 710 applicable to the equipment body 100 in embodiment 1, which comprises a device body comprising a mounting plate 711 for matching mounting with the three-axis platform 130, the mounting plate 711 being movably provided with a first-axis rotating plate 712 rotating around a first axis, and the tool assembly 140 being arranged at intervals along the length direction of the first-axis rotating plate 712; the tool assembly 140 is provided with a plurality of and sequentially forms a first station, a second station and the remaining stations arranged in this order.

[0062] It can be understood that the mounting plate 711 can be adjusted and adapted according to the three-axis platform 130 to be installed, and the device body can be quickly combined with the three-axis platform 130 through the mounting plate 711; at the same time, the user can keep the device body and the three-axis platform 130 unified output interface, so as to build a visual detection equipment with five-axis linkage function and unified control management. And when different detection objects are needed, the detection personnel can assemble and install the device body on the three-axis platform 130 that is more suitable for the detection object to obtain better visual acquisition effect and ensure higher accuracy of image analysis results. Therefore, the device body in the embodiment can preferably improve the operation flexibility of the detection personnel for the five-axis platform built for different detection objects.

[0063] Compared with the prior art, the device body in the embodiment can be stably and conveniently assembled for various three-axis platforms 130, and has better universality. Compared with the five-axis detection equipment built in one piece, the embodiment can preferably reduce the cost and facilitate disassembly and adjustment, and has better flexibility.

[0064] The two ends of the mounting plate 711 in the length direction are formed with assembly plates 7111 perpendicular to the mounting plate 711; the first axis rotation plate 712 is arranged between the two assembly plates 7111, and the first axis direction is a straight line direction perpendicular to the two assembly plates 7111.

[0065] The tool assembly 140 includes a second axis rotation station 910; the second axis rotation station 910 is uniformly arranged along the length direction of the first axis rotation plate 712, and the second axis rotation station 910 rotates around the second axis direction relative to the first axis rotation plate 712. The second axis direction is a straight line direction perpendicular to the rotation plate, and the second axis rotation station 910 rotates around the first axis direction with the first axis rotation plate 712 to constitute the first rotation direction of the tool assembly 140, and the rotation of the second rotation station around the second axis direction constitutes the second rotation direction of the tool assembly 140; the rotation angle of the second axis rotation station 910 around the second axis direction is limited within a limited angle.

[0066] The assembly plate 7111 at one end of the mounting plate 711 is provided with a side DD motor 713 connected with the first axis rotation plate 712; the side DD motor 713 drives the first axis rotation plate 712 to rotate to realize the rotation of the tool assembly 140 in the first rotation direction;

[0067] Specifically, the side edge DD motor 713 is controlled by an external control signal to control the rotation angle; so as to stably drive the first shaft rotating plate 712 to rotate by a corresponding angle; each second shaft rotating station 910 arranged at the first shaft rotating plate 712 can also rotate in the first rotating direction, so as to adjust the posture according to the detection requirement in the detection process to make the detection object at a better angle suitable for camera shooting.

[0068] The first shaft rotating plate 712 is provided with a plurality of station motors 911 along the length direction, and each station motor 911 is used to drive each second shaft rotating station 910 to rotate to realize the rotation of the tooling assembly 140 in the second rotating direction.

[0069] Each station motor 911 of each station is controlled by an external control signal to control the rotation angle. So that each station motor 911 can stably drive each rotating station to rotate by a certain angle, and then cooperate with the first rotating direction of the tooling assembly 140 to make the detection object fixed at each station have two axial degrees of freedom, and then better meet the angle requirement in the detection process.

[0070] The second shaft rotating station 910 includes a placement disc 912, and the placement disc 912 is provided with a suction disc bottom plate 913 on the surface away from the station motor 911, and the suction disc bottom plate 913 is provided with a suction disc mounting plate away from the placement disc 912; The suction disc mounting plate is uniformly distributed with a plurality of positioning suction discs 915 for adsorbing and fixing the detection object, and the suction direction of the positioning suction disc 915 is away from the suction disc bottom plate 913.

[0071] Specifically, the detection object can be quickly and conveniently adsorbed and positioned at each station by the positioning suction disc 915, so as to preferably improve the feeding speed of the worker when feeding the detection object, and then improve the processing rate of the entire detection process. In addition, the installation position of each positioning suction disc 915 can be conveniently installed and distributed according to the shape of the detection object to be detected, so as to ensure that the device body in the embodiment can be preferably applied to different detection objects.

[0072] The bottom wall away from the suction disc mounting plate of the placement disc 912 is provided with a screw hole 916 for installing a screw, and the outer edge of the placement disc 912 is provided with a vertical partition plate 917 away from the mounting plate 711.

[0073] The bottom position of the second shaft rotating station 910 is provided with a limiting plate 918 for cooperating with the vertical partition plate 917 to limit the rotation of the second rotating station, and the side of the limiting plate 918 close to the placement disc 912 is formed with a limiting protrusion 9181 for cooperating with the screw to form a hard limit.

[0074] When the station motor 911 is at zero position, the included angle between the limiting protrusion 9181 and the screw along the circumferential direction of the placement disc 912 is one hundred and eighty degrees; the width of the screw and the limiting protrusion 9181 itself limits the angle of the one-way rotation of the station motor 911 within one hundred and eighty degrees.

[0075] Specifically, the second rotating station in the embodiment has zero position and two rotating directions of positive direction and reverse direction under the driving of the station motor 911, and the air pipe will be cut off when the station motor 911 rotates to one hundred and eighty degrees, so that the rotation angle of the second rotating station is preferably limited by the partition plate, the limiting plate 918, the screw and the limiting protrusion 9181 formed on the limiting plate 918, so as to ensure that the detection needs are met while avoiding the situation of cutting off the air pipe.

[0076] The outer wall of the limiting plate 918 is provided with a photoelectric switch 9182 for identifying the rotating direction of the station motor 911.

[0077] Specifically, in the embodiment, the rotating direction of the station motor 911 can be preferably identified by the photoelectric switch 9182 to determine whether the station motor 911 is working normally under external control in real time, so that the station motor 911 can be identified and found in time when it works abnormally, and then the detection personnel can timely process to avoid serious consequences.

[0078] Embodiment 3

[0079] In combination Figures 13-14 , the embodiment provides a multi-station consistency calibration block of a multi-axis linkage visual detection equipment, which can be placed at the tool assembly 140 in the embodiment 1 or the embodiment 2 and cooperate with the visual acquisition assembly 120 to calibrate the equipment main body 100 in the embodiment 1 or the device main body in the embodiment 2; it comprises a calibration block main body 1300, the calibration block main body 1300 has a length L and a width W consistent with the detection object; a rectangular reference block 1310 with a length l is formed at the calibration block main body 1300.

[0080] Specifically, the length L and the width W of the calibration block main body 1300 can be adjusted to adapt to the detection object required to be detected, so as to preferably reduce the error existing in the calibration process before detecting different detection objects. In addition, the reference block 1310 with the length l and the width w can preferably serve as a reference in the calibration process.

[0081] The thickness of the calibration block main body 1300 is consistent with the detection object. Thus, the influence caused by the deviation of the motion position on the X, Y and Z axes can be reduced.

[0082] The bottom surface of the calibration block body 1300 is used to be positioned and matched with the work station to be calibrated. The top surface of the calibration block body 1300 is formed with a groove 1320, and the reference block 1310 is protrudedly formed in the middle of the groove 1320; the length l and the width w of the reference block 1310 can be used as the reference in the calibration process.

[0083] A plurality of reinforcing ribs 1330 are formed between the reference block 1310 in the groove 1320 and the inner side wall of the groove 1320. It can be understood that the reinforcing ribs 1330 can preferably ensure the strength of the calibration block body 1300 to improve the durability.

[0084] The material of the calibration block body 1300 is selected to be invar steel. The invar steel has a small linear expansion coefficient, thereby preferably reducing the influence of temperature on the size of the calibration block.

[0085] Embodiment 4

[0086] The embodiment provides a calibration method for the device body in Embodiment 1 or Embodiment 2, which is used with the visual acquisition assembly 120 and the calibration block in Embodiment 3, and the calibration is performed by the following steps; the XYZ axis space coordinate system is established in the space where the device body is located, the Z axis is formed along the vertical direction, and the X axis and the Y axis are formed along the horizontal plane and are perpendicular to each other; the second moving direction is the Z axis direction; the rectangular reference block 1310 at the calibration block has a length l;

[0087] Step S1: camera calibration

[0088] The conventional camera calibration methods such as the checkerboard and the dot are used to sequentially correct the distortion of each lens at each work station;

[0089] Step S2: multi-station motor 911 consistency calibration; (second rotation direction calibration)

[0090] Step S3: side DD motor 713 consistency calibration (first rotation direction calibration).

[0091] The device body applicable to the calibration method in the embodiment includes a tool assembly 140 for placing a detection object and having a first rotation direction and a second rotation direction; the tool assembly 140 is capable of placing a calibration block, and the calibration block is formed with a rectangular reference block 1310;

[0092] The tool assembly 140 is provided with a plurality of and sequentially formed first work stations, second work stations and remaining work stations arranged in this order; the tool assembly 140 at each work station is driven by the side DD motor 713 to realize rotation in the first rotation direction; the tool assembly 140 at each work station is respectively driven by the work station motor 911 of the corresponding work station to realize rotation in the second rotation direction;

[0093] The device body 100 further comprises a visual acquisition assembly 120 having a second moving direction, a rotation axis of the tool assembly 140 in the first rotation direction is orthogonal to the second moving direction of the visual acquisition assembly 120; a rotation axis of the tool assembly 140 in the second rotation direction is consistent with the second moving direction of the visual acquisition assembly 120; and the visual acquisition assembly 120 is provided with a plurality of and corresponds to the tool assembly 140 one by one.

[0094] The tool assembly 140 can be located in a detection area formed at the visual acquisition assembly 120. The side DD motor 713 and the station motor 911 at each station control the rotation angle through an external control signal.

[0095] Specifically, in the embodiment, the first step S1 can preferably ensure that each detection surface is not distorted when moving to the forward camera position, thereby ensuring the consistency of the lens in collecting images at the same visual acquisition position.

[0096] Further, the calibration process in steps S2 and S3 can preferably obtain errors generated in the installation process and errors generated in the machining and assembly of the workpiece itself through the corresponding reference; thereby ensuring that in the subsequent visual image acquisition process, the worker can offset the aforementioned errors through program setting or mechanical adjustment, thereby effectively avoiding the adverse effects of the aforementioned errors on the detection results, such as differences in the detection image defect features collected at each station; thereby improving the accuracy of the detection results.

[0097] Meanwhile, in the calibration method of the embodiment, in addition to the device body that needs to be calibrated and the three-axis platform 130 used to build the multi-axis detection device; only the additional use of the calibration block body 1300 can completely complete the entire calibration process, so that the calibration process in the embodiment is more convenient and stable than the prior art, and has lower cost. In addition, it is worth noting that the calibration block body 1300 used by the calibration personnel can be made according to the detection object to be detected, so that the real detection situation can be preferably simulated in the calibration process, thereby achieving the best calibration effect suitable for the detection object, ensuring high calibration precision and reducing errors in the actual detection process.

[0098] Embodiment 5

[0099] The embodiment provides a multi-station motor 911 consistency calibration method suitable for step S2 in embodiment 4, in the embodiment, the visual acquisition assembly 120 is a light source and a camera, which specifically includes the following steps:

[0100] Step S21, place and fix the calibration block at the first station;

[0101] Step S22, the visual acquisition component 120 corresponding to the first station is adjusted along the Z axis to make the image clear, and then the first station is imaged to obtain an image i0 of the station motor 911 at the zero position of the first station;

[0102] Step S23: the station motor 911 at the first station is rotated in the positive direction by an angle θ, n*θ=180°; the visual acquisition component 120 is imaged, and processing is performed to obtain an image i 1， and compared with i0 to obtain a comparison result;

[0103] Step S24: according to the steps in S23, the station motor 911 at the first station is sequentially rotated to a position of (n-1)*θ to obtain images i2 to i (n-1) and compared with the image i0 to obtain a comparison result;

[0104] Step S25: the station motor 911 at the first station returns to the original position;

[0105] Step S26: repeat steps S22 to S24 N times to obtain the comparison results of each image relative to i0;

[0106] Step S27: take the average of the comparison results multiple times as the reference value of the first station in the positive direction at each (n-1)*θ angle;

[0107] Step S28: reverse the station motor 911 at the first station according to steps S23 to S27 to obtain the reference value of the first station in the reverse direction;

[0108] Step S29: the station motor 911 at the first station is reset, the camera corresponding to the first station is raised along the Z axis to return to the original position; the calibration block is loosened, removed, and placed on the second station;

[0109] Step S210: the camera at the second station obtains the reference values of the second station in the positive direction and the reverse direction at each (n-1)*θ angle according to steps S22 to S28;

[0110] Step S211: complete the reference values of the remaining stations in the positive direction and the reverse direction at each (n-1)*θ angle according to steps S29 to S210;

[0111] Step S212: taking the first station as a reference, calculate the compensation values of the remaining stations in the positive direction and the reverse direction at each (n-1)*θ angle to complete the calibration of the consistency of the station motor 911.

[0112] Specifically, in the embodiment, the calibration block is used as a reference for image comparison to obtain the compensation value of the remaining stations relative to the first station in the second rotation direction; so that the worker can take measures to offset the error by using the compensation value as a reference; so as to ensure the consistency of the station motor 911 in rotation at the multi-station, that is, the rotation consistency of the multi-station in the second rotation direction; and further ensure the consistency and accuracy of the detection images collected by the vision acquisition assembly 120 at each station.

[0113] Further, the θ angle in step S23 in the embodiment can be selected according to different detection objects, so as to ensure that the detection precision required by the detection object is met while avoiding over-calibration, thereby improving the calibration efficiency and saving costs.

[0114] In addition, the calibration block in step S21 is fixed by the positioning suction cup 915 at the first station. Since the positioning suction cup 915 at each station is arranged according to the detection object to be detected, the calibration block consistent with the length, width and thickness of the detection object can be firmly fixed by the positioning suction cup 915 at the station; so as to effectively avoid the situation that the calibration precision is affected due to the displacement of the calibration block caused by the insecure fixation during the calibration process.

[0115] In steps S23 and S24, the comparison quantity is i1, i2 to i (n-1) Relative to the change s of the l-side middle line angle in i0 11 , s 21 to s (n-1)1 .

[0116] In steps S27 and S28, the reference value is the angle value of the l-side middle line, and the calculation formula of the reference value in the positive direction is The calculation formula of the reference value in the negative direction is The compensation value calculation method in step S212 is the positive direction compensation value S mz = S mz(n-1) -S 1z(n-1) and the negative direction compensation value S mf = S mf(n-1) -S 1f(n-1) The positive direction compensation value and the negative direction compensation value obtained by the foregoing steps can be used as a reference to enable the detection personnel to control and adjust the rotation angle of the corresponding motor to realize the consistency of the multi-station.

[0117] Specifically, the embodiment takes the variation angle of the middle line of the l side of the reference block 1310 at the calibration block main body 1300 of the calibration block as the contrast reference; on one hand, the variation amount of the middle line angle of the l side can be clearly identified in the collected image when the image contrast is performed; on the other hand, the variation of the middle line angle of the l side can be directly corresponding to the rotation angle of the station motor 911, thereby ensuring that the error is small and the variation sensitivity is high.

[0118] It can be understood that, by obtaining the compensation values in the positive direction and the reverse direction, the deviation existing when the other stations and the first station rotate at different angles can be preferably obtained, so that the detection personnel can take the compensation value as a reference to eliminate the deviation through program setting to ensure the consistency of the multi-station, thereby ensuring the synchronous and stable operation of the entire detection process. Therefore, the situation that the photographing and contrast analysis are affected due to the difference in the rotation angles of the stations can be effectively avoided.

[0119] Embodiment 6

[0120] The embodiment provides a calibration method of a multi-axis linkage visual detection equipment suitable for step S3 in embodiment 4, which comprises the following steps:

[0121] Step S31, the calibration block is placed and fixed at the first station;

[0122] Step S32, the visual acquisition assembly 120 corresponding to the first station is adjusted along the Z axis to make the photographing clear, then the first station is photographed to obtain an image i0 of the station motor 911 at the first station at zero position;

[0123] Step S33, the side DD motor 713 is rotated by θ angle in the positive direction to drive the tool assembly 140 at each station to rotate, n*θ=180°; the visual acquisition assembly 120 is photographed and processed; and the image i1 of the first station when the side DD motor 713 is at θ angle is obtained and compared with i0 to obtain a contrast result;

[0124] Step S34, according to the step in S33, the side DD motor 713 is sequentially rotated to the position of (n-1)*θ to obtain the images i2 to i (n-1) and each is compared with the image i0 to obtain a contrast result;

[0125] Step S35, the side DD motor 713 returns to the original position;

[0126] Step S36, steps S32 to S34 are repeated N times to obtain the contrast results of each image relative to i0;

[0127] Step S37, the average value of the multiple contrast results is taken as the reference value of the first station in the positive direction at each (n-1)*θ angle;

[0128] Step S38, rotate the side DD motor 713 in the reverse direction according to the steps S33 to S37 to obtain the reference value of the first station in the reverse direction;

[0129] Step S39, reset the side DD motor 713, and the first station corresponds to the camera rising along the Z axis to reset; the calibration block is loosened and taken off and placed on the second station;

[0130] Step S310, the camera on the second station obtains the reference value of each (n-1)*θ angle in the positive direction and the reverse direction according to the steps S32 to S38;

[0131] Step S311, complete the reference value of each (n-1)*θ angle in the positive direction and the reverse direction of the remaining stations according to the steps S39 to S310;

[0132] Step S312, taking the first station as the reference, calculate the compensation value of each (n-1)*θ angle in the positive direction and the reverse direction of the remaining stations and complete the calibration of the consistency of each station through the compensation value.

[0133] In steps S33 and S34, the comparison quantity is i1, i2 to i (n-1) The length change d of the l side in i0 11 , d 21 to d (n-1)1 .

[0134] The reference value in steps S37 and S38 is selected as the length value of the l side, and the calculation formula of the positive direction reference value is The calculation formula of the reverse direction reference value is

[0135] The calculation formula of the compensation value of the positive direction in step S312 is d mz =d mz(n-1) -d 1z(n-1) , and the calculation formula of the compensation value of the reverse direction is d mf =d mf(n-1) -d 1f(n-1) .

[0136] Specifically, the calibration method in the embodiment obtains the reference value and the compensation value by taking the length change of the side l as the comparison quantity. On the one hand, since the projection length l' = l*cosθ of the side l of the reference block 1310 in the calibration block main body 1300 on the imaging plane of the camera exists a certain functional correspondence relationship with the rotation angle during the rotation of the side DD motor 713, the length change of the side l is taken as the calibration reference of the rotation angle, which is stable and reliable and can preferably ensure the calibration accuracy. On the other hand, the length of the side l can be clearly identified in the image collected by the camera, so that the situation of increasing the calibration difficulty due to the difficulty in identifying the selected reference quantity can be preferably avoided.

[0137] Understandably, by obtaining the compensation values of each station at different angles of rotation in the forward and reverse directions compared with the first station, the detection personnel can use the compensation values as a reference to offset the deviation between different stations through program setting, thereby ensuring the consistent and stable performance of the entire detection process.

[0138] In addition, it is worth noting that, compared with the commonly used laser interferometer in the prior art, the calibration method in the embodiment does not need to adjust the light, has high speed, small device volume, stable and convenient calibration process and low cost.

[0139] Embodiment 7

[0140] The embodiment provides a detection image acquisition method of a multi-axis linkage visual detection device based on the device main body 100 in embodiment 1, and the device main body 100 has been calibrated by the calibration method in embodiment 3 to reduce errors and ensure detection accuracy. In the embodiment, a space coordinate system of XYZ axes is established in the space where the device main body 100 is located, the Z axis is formed along the vertical direction, and the X axis and the Y axis are formed along the horizontal plane and perpendicular to each other. The first moving direction, the second moving direction and the third moving direction are the X axis direction, the Z axis direction and the Y axis direction respectively. In the embodiment, the visual acquisition assembly 120 is a light source and a camera.

[0141] The detection image acquisition method specifically includes the following steps:

[0142] Step S1, placing the detection object at the tool assembly 140 located in the detection area;

[0143] Step S2, detecting and acquiring images of the four inner side diagonals and the four inner sides of the detection object one by one by rotating the tool assembly 140 in the first rotation direction and the second rotation direction and moving the visual acquisition assembly 120 in the first moving direction and the second moving direction.

[0144] Step S3, after the detection image acquisition of the four inner side diagonals and the four inner sides of the detection object is completed, the detection image acquisition of the four edges on the plane of the detection object is performed.

[0145] Step S4, after all image acquisition is completed, the detection object is unloaded from the tooling assembly 140.

[0146] Further, in the embodiment, step S2 specifically comprises the following steps:

[0147] Step S2 specifically comprises the following steps:

[0148] Step S21, the tooling assembly 140 rotates 70° in the positive direction in the first rotation direction and rotates 35° in the negative direction in the second rotation direction, so that the first inner side diagonal of the detection object faces the vision acquisition assembly 120; the vision acquisition assembly 120 is adjusted along the Z axis to make the image acquisition clear, and then detection image acquisition is performed on the first inner side diagonal of the detection object;

[0149] Step S22, after the detection image acquisition of the first inner side diagonal of the detection object is completed, the tooling assembly 140 rotates 35° in the positive direction in the second rotation direction, the vision acquisition assembly 120 is adjusted along the Z axis to make the image acquisition clear, and then the vision acquisition assembly 120 is moved in the negative direction along the X axis until it faces one end of the first inner side edge of the detection object, and then the vision acquisition assembly 120 is moved in the positive direction along the X axis until it faces the other end of the first inner side edge, and in the movement process, detection image acquisition is performed on the first inner side edge of the detection object;

[0150] Step S23, after the detection image acquisition of the first inner side edge is completed, the tooling assembly 140 rotates 35° in the positive direction in the second rotation direction, the vision acquisition assembly 120 is moved along the X axis so that the second inner side diagonal faces the vision acquisition assembly 120, and the vision acquisition assembly 120 is adjusted along the Z axis to make the image acquisition clear; and then detection image acquisition is performed on the second inner side diagonal of the detection object;

[0151] Step S24, after the detection image acquisition of the second inner side diagonal is completed, the tooling assembly 140 rotates 55° in the positive direction in the second rotation direction, the vision acquisition assembly 120 is moved in the negative direction along the X axis so that one end of the second inner side edge faces the vision acquisition assembly 120, and then the vision acquisition assembly 120 is adjusted along the Z axis to make the image acquisition clear, and then the vision acquisition assembly 120 is moved in the positive direction along the X axis until it faces the other end of the second inner side edge, and in the movement process of the vision acquisition assembly 120 along the X axis, detection image acquisition is performed on the second inner side edge;

[0152] Step S25, after the detection image collection of the second inner side edge is completed, the tooling assembly 140 rotates 35° in the second rotation direction again in the positive direction, the vision acquisition assembly 120 is moved along the X axis to make it face the third inner side diagonal of the detection object, the vision acquisition assembly 120 is adjusted along the Z axis to make the image collection clear, and then the detection image collection is performed on the third inner side diagonal of the detection object;

[0153] Step S26, after the detection image collection of the third inner side diagonal is completed, the tooling assembly 140 rotates 55° in the second rotation direction again in the positive direction, the vision acquisition assembly 120 is moved along the X axis in the negative direction to make one end of the third inner side edge face the vision acquisition assembly 120, the vision acquisition assembly 120 is adjusted along the Z axis to make the image collection clear, then the vision acquisition assembly 120 is moved along the X axis in the positive direction until it faces the other end of the third inner side edge, and the detection image collection is performed on the third inner side edge during the movement of the vision acquisition assembly 120 along the X axis;

[0154] Step S27, after the detection image collection of the third inner side edge is completed, the tooling assembly 140 rotates 35° in the second rotation direction again in the positive direction, the vision acquisition assembly 120 is moved along the X axis to make it face the fourth inner side diagonal of the detection object, the vision acquisition assembly 120 is adjusted along the Z axis to make the image collection clear, and then the detection image collection is performed on the fourth inner side diagonal of the detection object;

[0155] Step S28, after the detection image collection of the fourth inner side diagonal is completed, the tooling assembly 140 rotates 55° in the second rotation direction again in the positive direction, the vision acquisition assembly 120 is moved along the X axis in the negative direction to make one end of the fourth inner side edge face the vision acquisition assembly 120, the vision acquisition assembly 120 is adjusted along the Z axis to make the image collection clear, then the vision acquisition assembly 120 is moved along the X axis in the positive direction until it faces the other end of the fourth inner side edge, and the detection image collection is performed on the fourth inner side edge during the movement of the vision acquisition assembly 120 along the X axis.

[0156] Specifically, in the embodiment, step S3 specifically includes the following steps,

[0157] Step S31, the vision acquisition assembly 120 is moved upward along the Z axis, the tooling assembly 140 rotates 70° in the first rotation direction in the reverse direction back to the positive direction, and the tooling assembly 140 rotates 90° in the second rotation direction in the reverse direction;

[0158] Step S32, the vision acquisition component 120 is moved along the X axis and the tool component 140 is moved along the Y axis to make one end of the first side of the detection object face the vision acquisition component 120, the vision acquisition component 120 is adjusted along the Z axis to make the image clear, the vision acquisition component 120 is moved along the X axis until it faces the other end of the first side of the detection object, and the detection image acquisition is completed for the first side during the movement;

[0159] Step S33, at this time, the vision acquisition component 120 faces one end of the second side of the detection object, and then the tool component 140 is moved along the Y axis until the vision acquisition component 120 faces the other end of the second side, and the detection image acquisition is completed for the second side during the movement;

[0160] Step S34, at this time, the vision acquisition component 120 faces one end of the third side of the detection object, and then the vision acquisition component 120 is moved along the X axis until it faces the other end of the third side, and the detection image acquisition is completed for the third side during the movement;

[0161] Step S35, at this time, the vision acquisition component 120 faces one end of the fourth side of the detection object, and then the tool component 140 is moved along the Y axis until the vision acquisition component 120 faces the other end of the fourth side, and the detection image acquisition is completed for the fourth side during the movement.

[0162] It can be understood that the detection image acquisition method in the embodiment can preferably detect the four sides and four corners of the detection object which are prone to defects, and detect the four sides on the plane, so as to have a wide detection range while maintaining high detection efficiency, thereby ensuring a high defective product detection rate.

[0163] Specifically, the detection image acquisition method in the embodiment can simultaneously acquire a plurality of detection objects placed at each station; in addition, during image acquisition at each position, the detection object to be acquired is always located at the station, and is photographed by the camera corresponding to the station. During the photographing process, the camera does not need to be adjusted again after adjusting the focal length and the shooting position, and the detection object only needs to follow the set rotation angle of the station motor 911 and the side DD motor 713 to complete the photographing of each position in turn; so that the key positions of the detection object can be stably and conveniently acquired during the whole photographing process, thereby preferably improving the image acquisition efficiency, and ensuring that the acquired images can be analyzed and processed to obtain the appearance defect detection result of the detection object.

[0164] And, in the image acquisition process, the rotation angles set by the station motor 911 and the side DD motor 713 and the rotation sequence of each angle can preferably ensure that each key part of the detection object can be covered, thereby preferably avoiding the situation of missing defects detection. And the rotation angles and the rotation sequence of each angle in the above process can preferably ensure that the overall process runs smoothly and efficiently in the entire detection process, with less invalid rotation, and the detection of each key part can be stably completed in turn in the rotation process.

[0165] In addition, after each station motor 911 and side DD motor 713 is calibrated by the calibration method in the foregoing embodiment 3, it can preferably ensure that each station can be kept synchronous in the detection process, thereby providing a good prerequisite for synchronous and stable multi-station detection image acquisition; thereby preferably ensuring that the visual image acquisition effect of the detection object at each station can be maintained at a relatively high consistent level, thereby ensuring the accuracy of subsequent analysis and detection of the acquired images.

[0166] Embodiment 8

[0167] In combination Figure 15 , the embodiment provides an application of the detection image acquisition method in embodiment 7 to the visual image acquisition of the middle frame 1400 of the mobile phone. It can be understood that by this method, the detection image acquisition of the parts prone to visual defects in the middle frame 1400 of the mobile phone can be preferably performed to cooperate with the subsequent analysis and detection and exclude defective products.

[0168] It is easy to understand that, on the basis of one or more embodiments provided in the present application, a person skilled in the art can combine, split, recombine, etc. to obtain other embodiments, and these embodiments do not exceed the protection scope of the present application.

[0169] The above describes the present application and its embodiments in a schematic manner, and the description is not restrictive. The embodiments shown in the drawings are only one of the embodiments of the present application, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by this, without departing from the spirit of the present application, without creative design, similar structure and embodiments can be obtained, which should belong to the protection scope of the present application.

Claims

1. A calibration method for a multi-axis linkage vision inspection device, characterized in that: A space coordinate system of XYZ axes is established in the space where the device body (100) is located, the Z axis is formed along the vertical direction, and the X axis and the Y axis are formed along the horizontal plane and perpendicular to each other; the second moving direction is the Z axis direction; the tool assembly (140) is capable of placing a calibration block, and the calibration block is formed with a rectangular reference block; It comprises the following steps: Step S1, the calibration block is placed and fixed at the first station; Step S2, the vision acquisition assembly (120) corresponding to the first station is adjusted along the Z axis to make the image clear, then the first station is imaged and an image i0 of the station motor (911) at the zero position at the first station is obtained; Step S3, the side DD motor (713) is rotated forward by θ angle to drive the tool assembly (140) at each station to rotate, n*θ=180°; the vision acquisition assembly (120) is imaged and processed; and an image i1 of the first station when the side DD motor (713) is at θ angle is obtained and compared with i0 to obtain a comparison result; Step S4, according to the step S3, the side DD motor (713) is rotated to the position of (n-1)*θ in turn, and the images i2 to i (n-1) and compared with the image i0 and the contrast results are obtained. Step S5, the side DD motor (713) returns to the original position; Step S6, steps S2 to S4 are repeated N times to obtain the comparison results of each image relative to i0; Step S7, the average value of the multiple comparison results is taken as the reference value of the first station in the positive direction at each (n-1)*θ angle; Step S8, the side DD motor (713) is rotated in the reverse direction according to steps S3 to S7 to obtain the reference value of the first station in the reverse direction; Step S9, the side DD motor (713) is reset, the camera corresponding to the first station is raised along the Z axis to reset; the calibration block is loosened and taken off and placed on the second station; Step S10, the camera on the second station obtains the reference values of the second station in the positive direction and the reverse direction at each (n-1)*θ angle according to steps S2 to S8; Step S11, the reference values of each (n-1)*θ angle in the positive direction and the reverse direction of the remaining stations are completed according to steps S9 to S10; Step S12, taking the first station as a reference, the compensation values of the remaining stations in the positive direction and the reverse direction at each (n-1)*θ angle are calculated and the calibration of the consistency of each station is completed through the compensation values.

2. The calibration method of a multi-axis linkage vision inspection apparatus according to claim 1, wherein: In step S3 and step S4, the comparison quantity is i1, i2 to i (n-1) The length change d of the l side in relation to i0 11 , d 21 to d （n-1）1 .

3. The calibration method of a multi-axis linkage vision inspection apparatus according to claim 1, wherein: The reference value in step S7 and step S8 is selected as the length value of the side l, and the calculation formula of the positive direction reference value is d 1z（n-1） = ; and the calculation formula of the negative direction reference value is d 1f（n-1） = .

4. The calibration method of a multi-axis linkage vision inspection apparatus according to claim 1, wherein: The positive direction compensation value and the reverse direction compensation value obtained in the foregoing steps can be used as a reference to control and adjust the rotation angle of the corresponding motor to realize the consistency of multiple stations.

5. A multi-axis vision inspection apparatus, characterized by: A calibration method for a multi-axis linkage visual detection device as claimed in any one of claims 1-4, comprising a device body (100), the device body (100) comprising a tool assembly (140) for placing a detection object and having a first rotation direction; the tool assembly (140) is provided with multiple and sequentially forms a first station, a second station and remaining stations arranged in this order; the tool assembly (140) at each station is driven by a side DD motor (713) to realize rotation in the first rotation direction; The device body (100) further comprises a vision acquisition assembly (120) having a second moving direction, and a rotation axis of the tool assembly (140) in the first rotation direction is orthogonal to the second moving direction of the vision acquisition assembly (120); the vision acquisition assembly (120) is provided with a plurality of and corresponds to the tool assembly (140) one by one.

6. The multi-axis linkage vision inspection apparatus according to claim 5, wherein: The tool assembly (140) can be located in a detection area formed at the vision acquisition assembly (120).

7. The multi-axis linkage vision inspection apparatus according to claim 5, wherein: The side DD motor (713) controls the rotation angle through an external control signal. ​ 8. The multi-axis linkage vision inspection apparatus according to claim 5, wherein: The tool assembly (140) can place a calibration block, and the calibration block is formed with a rectangular reference block; The calibration block is consistent with the shape and size of the detection object.

9. The multi-axis linkage vision inspection apparatus according to claim 8, wherein: The calibration block can be adsorbed and fixed by the positioning suction cup at each station.

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