A machine vision high-precision positioning device and method

Abstract

A high-precision positioning device and method for machine vision, which belongs to the field of industrial robot grasping and placing technology. The device includes a workbench, a processor, an industrial camera, a mechanical arm and a return to circle mechanism, and the return to circle mechanism is used to move the absorbed lens to a fixed position. The present invention uses the return to circle mechanism to make the lens in the same position each time the lens is absorbed, so as to achieve an error of no more than 0.02mm between the center of the final lens and the center of the lens barrel. The dual industrial cameras are set to effectively reduce the return to circle error that may be caused by friction during the return to circle process. The combination of the two effectively improves the accuracy of machine vision placement.

Description

Technical Field

[0001] The invention relates to the technical field of industrial robot grasping and placing, and in particular to a machine vision high-precision positioning and placing device. Background Art

[0002] Minimally invasive technology under medical endoscopes is an advanced diagnostic and treatment method in the current medical community, and is also the direction of development of internal and external medical technology. Medical endoscopes combined with minimally invasive technology have the characteristics of small trauma, fast postoperative recovery, and high cure rate, which reduces the harm to the patient's body, greatly alleviates the patient's pain, and shortens the medical cycle, which is recognized by the majority of patients and medical staff. However, traditional endoscopes have a precise structure and many tiny switches, making it difficult to disassemble and clean the parts one by one. Even extremely small residual microorganisms and secretions provide a possible environment for cross-infection. In order to improve this problem, adding a disposable endoscope protective cover to the endoscope not only greatly reduces the risk of cross-infection, but also avoids the complicated endoscope cleaning process.

[0003] However, the endoscope protective cover has high requirements for the centration of the barrel and the lens, and the center distance between the two must not exceed 0.03mm, which places extremely high demands on manufacturing and processing. In order to ensure the quality of the final product, the existing system processing cost and manufacturing process are relatively high or complicated, but these two factors make the manufacturing cost of the final product high and its competitiveness in the market poor. Excessive manufacturing costs are the cost of the entire system, and ultra-high precision robotic arms are expensive. The complex manufacturing process is mainly reflected in the complicated steps required to ensure the accuracy of the lens placement process. The quality of the product is the key to the success of the entire system.

[0004] There is currently no specific feasible solution on the market that can ensure low system processing costs, simple manufacturing process and final product quality that meets the required requirements. Summary of the invention

[0005] To this end, the present invention provides a machine vision high-precision positioning and placement device, which ensures product quality while meeting relatively low costs and making the manufacturing process simpler, and overcomes the problem of low versatility of the original device for different models of endoscope barrels.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: a machine vision high-precision positioning device, which includes a workbench, a loading table and a discharge table, the loading table is placed on the lens, and the discharge table is provided with a lens barrel;

[0007] The workbench is also provided with a return-to-circle mechanism, a workbench camera and a mechanical arm. In the return-to-circle mechanism, four groups of L-shaped baffle assemblies and a center plate are symmetrically arranged on the return-to-circle bottom plate; a spring is arranged between the spring baffle and the L-shaped baffle in the L-shaped baffle assembly, and a slide rail is arranged between the spring baffle and the center plate, and the slide rail drives the L-shaped baffle to perform reciprocating linear motion on the slide rail; the area above the center plate surrounded by the four L-shaped baffles is the middle cavity;

[0008] A robotic arm camera and a clamping vacuum suction pen are arranged at the end of the robotic arm, and the vacuum suction pen is connected to a vacuum air pump through an air pipe; an air path is arranged between the front end of the vacuum suction pen and the rear end of the vacuum suction pen, the front end of the vacuum suction pen is fixed in the air pipe through a fixing groove, and the rear end of the vacuum suction pen acts on the lens.

[0009] A working method of a machine vision high-precision positioning device comprises the following steps:

[0010] a. Turn on the vacuum air pump and adjust its suction force to ensure that the lens does not fall off during the movement; the vacuum air pump is connected to the vacuum suction pen through an air pipe; the mechanical arm drives the vacuum suction pen to start working;

[0011] b. The robot arm moves to the top of the loading platform and reaches down through the palletizing function, and the lenses are adsorbed to the end of the vacuum suction pen; the palletizing function is to stack the lenses in an integrated unitized manner;

[0012] c. The robotic arm drives the vacuum suction pen and the lens to the top of the middle cavity of the return-to-circle mechanism, and the end of the robotic arm reaches the end of the vacuum suction pen to drive the lens into the middle cavity;

[0013] The robot arm drives the end of the vacuum pen and the lens to hit the L-shaped baffles at the front and left ends respectively, and then hit the L-shaped baffles at the rear and right ends respectively. At this time, the rear end and the right end of the vacuum pen are aligned;

[0014] After the return to circle action is completed, the L-shaped baffle rebounds to the initial position along the slide rail under the action of the spring;

[0015] d. The robotic arm moves the lens to the top of the workbench camera. The processor calibrates the offset distance of the lens center relative to the center of the vacuum pen end according to the lens image and the vacuum pen image collected by the workbench camera, and performs secondary positioning of the lens position.

[0016] e. Move the robotic arm, and the robotic arm camera collects images of the lens barrel. According to the image of the lens barrel collected by the robotic arm camera, calibrate the position of the lens barrel on the unloading table, and then select the placement position of the lens according to the position of the lens barrel, determine the offset direction and offset distance between the lens barrel and the lens, and compensate, and control the vacuum suction pen at the end of the robotic arm to place the lens barrel;

[0017] The offset direction is the direction between the center of the vacuum pen end and the center of the lens barrel, and the offset distance is the distance difference between the center of the vacuum pen end and the center of the lens barrel.

[0018] Compared with the prior art, the beneficial effect of the present invention is that the traditional lens placement method is manual placement, which is inefficient, has a poor final yield rate, and cannot place certain types of lens barrels. The present invention solves the problem of being unable to place certain types of lens barrels by using a high-precision camera in conjunction with a mechanical placement device, and improves work efficiency and yield rate, effectively improving the efficiency of making the entire endoscope protective cover. The present invention can effectively fix the lens to the fixed position of the vacuum suction pen by setting a return to circle mechanism, and the lens in a standard posture can effectively maintain a fixed posture when the mechanical arm moves, which is convenient for the mechanical arm to place the lens and identify the center of the lens, further improving the accuracy of machine vision placement.

[0019] The present invention uses a vacuum suction pen to suck the lens. The suction force can keep the lens in a fixed position during movement and can be adsorbed on the UV film when placing. The vacuum suction pen can adapt to various types of lenses, further improving the versatility of machine vision placement. The present invention uses a special glass pad on the unloading table to reduce the deformation of the UV film caused by contact with the UV film when the mechanical arm performs the placement operation, further improving the accuracy of machine vision placement.

[0020] The processor of the present invention calibrates the offset distance of the lens relative to the end of the vacuum pen according to the lens image and the vacuum pen image collected by the high-precision industrial camera, and adds this result to the result assembly program, which is equivalent to a secondary positioning of the position of the lens, further improving the accuracy of machine vision placement. The processor of the present invention obtains the image of the lens barrel after placement, determines the offset direction and offset distance of the lens barrel and the lens, and selects a compensation method according to the offset direction and offset distance. By adjusting the offset direction and offset distance of the lens barrel corresponding to the lens in different areas, the accuracy of lens placement can be effectively guaranteed, further improving the repeatability of machine vision placement. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a structural block diagram of the machine vision high-precision positioning and placement device of the present invention.

[0023] Figure 2Schematic diagram of a high-precision positioning and grasping device of machine vision according to an embodiment of the present invention.

[0024] Figure 3 Schematic diagram of a vacuum pen according to an embodiment of the present invention.

[0025] Figure 4 It is a schematic diagram of the circle-returning mechanism according to an embodiment of the present invention.

[0026] Figure 5 Schematic diagram of the lens placement process according to an embodiment of the present invention.

[0027] Figure 6 This is a specific implementation effect diagram of an embodiment of the present invention.

[0028] Among them: Among them: 1. return to circle mechanism, 1a. return to circle bottom plate, 1b. center plate, 1c. middle cavity, 1d. spring baffle, 1e. spring, 1f. slide rail, 1g. L-shaped baffle, 2. loading table, 3. lens, 4. robotic arm, 5. vacuum air pump, 6. robotic arm camera, 6a. workbench camera, 7. vacuum suction pen, 8. workbench, 9. unloading table, 10. lens barrel, 11. fixing groove, 12. air path, 13. end of vacuum suction pen, 14. head end of vacuum suction pen. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0030] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "front", and "back" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0031] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In order to better understand this plan, the professional terms involved are explained below:

[0033] SCARA Robot Arm: SCARA Robot Arms usually have 4 axes. They have two parallel arms that can move in one plane. The last axis is at right angles to the other axes and is compliant.

[0034] See also Figure 1 As shown, it is a structural block diagram of the machine vision high-precision positioning and placement device of the present invention, and the machine vision high-precision positioning and placement device includes:

[0035] Workbench: It is used to place materials and various devices. It is made of marble to reduce the vibration caused during the operation of the device.

[0036] Rounding mechanism: It is installed on the workbench surface to perform rounding correction operation;

[0037] SCARA robot arm: It is installed on the workbench surface, including a vacuum suction pen installed at the end of the J4 axis of the SCARA robot arm, which is used to suck the lens and round the lenses of various models, including sucking and placing the lenses;

[0038] Vacuum air pump: It is used to provide negative pressure to enable the vacuum suction pen installed at the end of the J4 axis of the SCARA robot arm to work;

[0039] Industrial camera: It is connected to the SCARA robot arm and the workbench respectively, and the robot arm camera 6 is set at the end of the SCARA robot arm J4 axis and the platform opening of the workbench camera 6a to collect images of the lens barrel and the lens;

[0040] Processor: It is connected to the SCARA robot arm and the high-precision robot arm camera 6 and the workbench camera 6a respectively, and is used to calibrate the position of the lens barrel and the secondary correction respectively. According to the obtained image-related data, the robot arm placement position is calculated according to a pre-set algorithm, and the robot arm is controlled to accurately place the lens; the processor stores the lens position information and calibration files, and has built-in machine vision software, which supports 2D / 3D deep learning, robot automatic calibration, supports GenICam standard, can be connected to cameras of various brands, supports advanced programming tools such as script programming, and runs on Windows.

[0041] The robot arm camera 6 and the workbench camera 6a are intelligent industrial cameras. The processor includes a single-camera visual guidance system, and its parameters include: its guidance accuracy is ±0.01mm; it supports automatic or manual gain adjustment, and the shooting method is the robot soft trigger control depth camera shooting, which can output position and angle offset data; the system also supports nine-point calibration, rotation center calibration and automatic calibration. It can be understood that high-precision positioning means that the guidance accuracy of the processor is ±0.01mm, which is higher than more than 70% of the visual positioning placement devices in the application field.

[0042] A mechanical arm camera 6 is installed on the mechanical arm. The cooperation of the mechanical arm camera 6 and the mechanical placement device solves the problem that some types of lens barrels cannot be placed, improves work efficiency and yield rate, and effectively improves the efficiency of making the entire endoscope protective cover.

[0043] Among them, the rounding correction is that after the SCARA robot arm absorbs the lens, it moves in the rounding mechanism according to the preset action and then moves the lens to the fixed position at the end of the vacuum suction pen;

[0044] After the lens is calibrated to return to the roundness, there may still be movement of the lens position caused by the friction between the baffle and the lens. Therefore, the robot arm moves the lens again to the top of the workbench camera 6a to obtain the lens image, and the processor calculates the distance and direction of the lens center offset;

[0045] The vacuum pen has a needle-like shape at the end, which can adapt to various types of lenses. The groove on the top allows for easy installation on the robotic arm.

[0046] See also Figure 3 As shown, it is a structural diagram of the vacuum suction pen of an embodiment of the present invention. The lens is adsorbed on the end 13 of the vacuum suction pen. The vacuum suction pen is connected to the end of the robot arm J4 axis through the groove 11. The air path 12 allows the vacuum air pump 5 to apply negative pressure to the lens 3.

[0047] The workbench 8 is provided with a loading platform 2 and a discharging platform 9. The loading platform 2 is provided with a plurality of circular grooves, in which lenses 3 are placed, so as to facilitate the stacking operation of the robot arm. The discharging platform 9 is a plated steel plate to prevent reflection, and a glass pad is placed under the discharging platform 9. The glass pad is made of a layer of laminated glass, a layer of acrylic vulcanized rubber, a layer of PET film, a layer of silicone and a layer of PET release film. The glass pad can reduce the deformation of the UV film caused by contact with the UV film in the lens barrel 10 when the robot arm 4 performs the placement operation.

[0048] The UV film is coated with a glue that quickly loses its stickiness under ultraviolet light of a specific wavelength, so it is easy to remove from the UV film after the lens is placed. The glue dispensing step is to use a glue dispenser to add light-shielding glue to the gap between the placed lens barrel and the lens.

[0049] When the above technical solution is adopted,

[0050] a. Turn on the vacuum air pump 5 and adjust its suction force to the maximum value. The vacuum air pump 5 is connected to the vacuum suction pen 7 through the air pipe 15. The vacuum suction pen 7 installed on the robot arm 4 starts to work. The suction force can adsorb and fix the lens 3 on the end 13 of the vacuum suction pen during the movement and can be adsorbed on the UV film during the placement action.

[0051] b. The robot arm moves to the designated position through the stacking function, and probes down to 2mm. The lens 3 is sucked to the end 13 of the vacuum pen. At this time, the position of the lens 3 at the end 13 of the vacuum pen is a random position and cannot be determined. The robot arm 4 will move again to prevent the lens 3 from not being sucked to the end 13 of the vacuum pen. The vacuum pen 7 can adapt to various models of lenses 3, further improving the versatility of machine vision placement.

[0052] c. The robot arm 4 moves to the preset return structure 1, moves backward until it collides with the rear baffle of the return mechanism, and continues to move backward for a distance after contacting the rear baffle. At this time, the rear end of the lens is flush with the rear end of the vacuum suction pen. The return operation can effectively fix the lens to the fixed position of the vacuum suction pen. The lens in a standard posture can effectively maintain a fixed posture when the robot arm moves, which is convenient for the robot arm to place the lens, further improving the efficiency of machine vision placement.

[0053] The return to circle position includes the horizontal height of the end of the vacuum suction pen being lower than the highest plane of the return to circle mechanism baffle, and the plane position is the center position of the four baffles of the return to circle mechanism. The robot arm moves to the front baffle, left baffle, and right baffle of the return to circle mechanism respectively, so that the lens moves to a fixed position, at which time the rear end and right end of the lens coincide with the rear end and right end of the end of the vacuum suction pen respectively. The return to circle mechanism baffle is an L-shaped baffle, the lower end of which is connected to a slider, and the slider is connected to a limit spring. After each return to circle action, it will rebound to the initial position.

[0054] d. Secondary positioning of lens position

[0055] The processor calibrates the offset distance of the lens relative to the end of the vacuum pen according to the lens image and the vacuum pen image collected by the workbench camera 6a, and records the result in the processor. The actual position of the final robot arm placement is obtained by combining the position information, offset information and calibrated initial position of the lens obtained by the processor at each step, which is equivalent to a secondary positioning of the lens position, further improving the accuracy of machine vision placement.

[0056] e. Precise placement of lenses

[0057] The processor calibrates the position of the lens barrel 10 on the unloading platform 9 according to the lens barrel image collected by the robot arm camera 6, and the processor controls the vacuum suction pen 7 installed on the robot arm 4 to place the lens barrel 10 at a position corresponding to a preset height according to a preset placement strategy;

[0058] The preset placement strategy is that the processor selects the placement position of the lens according to the placement position of the lens barrel and controls the vacuum suction pen installed on the SCARA robot arm to place the lens barrel on the UV film;

[0059] The placement position is the lens barrel position obtained by the processor processing the image data, which is a combination of the distance and direction of the lens center offset relative to the center of the vacuum pen end;

[0060] The processor obtains the image of the lens barrel after placement, determines the offset direction and offset distance of the lens barrel and the lens, and selects a compensation method according to the offset direction and offset distance. The compensation method is to determine the fixed offset direction and offset distance at the current placement position according to the offset direction and offset distance, and the processor gives the corresponding compensation direction and compensation distance.

[0061] The offset direction is the direction between the center of the lens and the center of the lens barrel, and the offset distance is the difference between the center of the vacuum pen end and the center of the lens barrel. By adjusting the offset direction and offset distance of the lens barrel corresponding to different areas, the accuracy of lens placement can be effectively guaranteed, further improving the accuracy of machine vision placement.

[0062] Example 1: Please refer to Figure 2 As shown, it is a schematic diagram of a high-precision positioning and placing device for machine vision according to an embodiment of the present invention. The device is provided with a workbench 8, on which a SCARA robot arm 4 is installed. The SCARA robot arm 4 is installed with a vacuum suction pen 7 and an industrial camera 6. After the vacuum air pump 5 is started, the SCARA robot arm 4 moves to the loading table 2 to absorb the lens 2, and the SCARA robot arm 4 moves to the return device 1 to adjust the lens to a standard posture after the return, and moves to the industrial camera for secondary positioning. After the processor recognizes and assembles the results, the SCARA robot arm 4 moves to the unloading table to place the lens in the specified lens barrel. The result is shown in FIG. Figure 5 As shown,

[0063] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A working method of a machine vision high-precision positioning device, characterized in that: The device comprises a workbench (8), a loading platform (2) and a discharging platform (9), wherein a lens (3) is placed on the loading platform (2) and a lens barrel (10) is arranged on the discharging platform (9); The workbench (8) is provided with a return-to-circle mechanism (1), a workbench camera (6a) and a mechanical arm (4); in the return-to-circle mechanism (1), four groups of L-shaped baffle assemblies and a center plate (1b) are symmetrically arranged on the return-to-circle bottom plate (1a); a spring (1e) is arranged between the spring baffle (1d) and the L-shaped baffle (1g) in the L-shaped baffle assembly, and a slide rail (1f) is arranged between the spring baffle (1d) and the center plate (1b); the slide rail drives the L-shaped baffle (1g) to perform reciprocating linear motion on the slide rail (1f); and the area above the center plate (1b) surrounded by the four L-shaped baffles (1g) is an intermediate cavity (1c); A robotic arm camera (6) and a clamping vacuum suction pen (7) are arranged at the end of the robotic arm (4); the vacuum suction pen (7) is connected to a vacuum air pump (5) via an air pipe (15); an air path (12) is arranged between the vacuum suction pen head end (14) and the vacuum suction pen tail end (13); the vacuum suction pen head end (14) is fixed in the air pipe (15) via a fixing groove (11), and the vacuum suction pen tail end (13) acts on the lens (3); The working method comprises the following steps: a. Turn on the vacuum air pump (5) and adjust its suction force to ensure that the lens does not fall off during the movement; the vacuum air pump (5) is connected to the vacuum suction pen (7) through the air pipe (15); the mechanical arm (4) drives the vacuum suction pen (7) to start working; b. The robot arm (4) moves to the top of the loading platform (2) and reaches down through the stacking function, and the lens (3) is adsorbed onto the end of the vacuum suction pen (13); the stacking function is to stack the lenses (3) in an integrated unitized manner; c. The mechanical arm (4) drives the vacuum suction pen (7) and the lens (3) to the top of the middle cavity (1c) of the return mechanism (1), and the end of the mechanical arm (4) reaches down to the end of the vacuum suction pen (13) to drive the lens (3) into the middle cavity (1c); The mechanical arm (4) drives the vacuum pen end (13) and the lens (3) to first hit the front end and the left end of the L-shaped baffle (1g) respectively, and then hit the rear end and the right end of the L-shaped baffle (1g) respectively. At this time, the rear end and the right end of the vacuum pen end (13) are aligned with the rear end and the right end of the lens (3); After the return to circle action is completed, the L-shaped baffle (1g) rebounds to the initial position along the slide rail (1f) under the action of the spring (1e); d. The robotic arm (4) moves the lens (3) to the top of the workbench camera (6a), and the processor calibrates the offset distance of the lens center relative to the center of the vacuum suction pen end according to the lens image and the vacuum suction pen image captured by the workbench camera (6a), and performs secondary positioning of the position of the lens (3); e. Move the robotic arm (4), and use the robotic arm camera (6) to collect an image of the lens barrel (10). According to the image of the lens barrel (10) collected by the robotic arm camera (6), calibrate the position of the lens barrel (10) on the unloading platform (9), and then select the placement position of the lens (3) according to the position of the lens barrel (10), determine the offset direction and offset distance between the lens barrel and the lens, and compensate for them, and control the vacuum suction pen (7) at the end of the robotic arm (4) to place the lens barrel (10); The offset direction is the direction between the center of the vacuum pen end and the center of the lens barrel, and the offset distance is the distance difference between the center of the vacuum pen end and the center of the lens barrel.

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