Pre-oiling auxiliary device for placing light and thin elastic sheets

Abstract

The invention relates to a pre-oiling auxiliary device for placing light and thin elastic sheets, which belongs to the technical field of precision assembly and comprises a manipulator, an oiling mechanism, a visual system and a reflective analysis module. The oil dispensing mechanism and the visual system are mounted on the manipulator, the manipulator is used for taking and placing the elastic sheet, and the oil dispensing mechanism is used for performing oil dispensing action before the elastic sheet is placed on a workpiece; the visual system comprises an industrial camera, an annular coaxial light source and a polaroid; the industrial camera is arranged on the manipulator, the annular coaxial light source and the industrial camera are coaxially nested, and the polaroid is attached to the output surface of the light source; the industrial camera is connected with the reflection analysis module and uploads a shot workpiece point oil image to the reflection analysis module; the light reflection analysis module judges the oil dispensing effectiveness by identifying the brightness enhancement characteristic of the oil dispensing area relative to the oil-free area, the adhesive force generated by pre-oil dispensing is applied to solve the problems that a light and thin elastic piece is prone to being affected by airflow and static electricity and falls down and is obliquely placed, and the physical stability of placement is fundamentally improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision assembly, and in particular relates to a pre-oiling auxiliary device for placing light and thin spring pieces. Background Art

[0002] The assembly process for precision electronics, microelectromechanical systems (MEMS), and microconnectors often requires handling tiny, thin metal springs. These springs typically serve as electrical contacts, mechanical sensors, or elastic supports. The precision and reliability of their mounting directly determine the performance and yield of the final product. However, automated handling of these thin springs presents significant challenges, including static electricity and high airflow sensitivity.

[0003] Spring clips are prone to triboelectric charging. Their extremely small mass and ultra-thin thickness result in a large surface-to-volume ratio, leading to a high accumulation of static charge that is difficult to dissipate. During the pickup process, static electricity can cause the spring clip to cling to the tray or carrier, making it difficult to pick up. During the placement process, static electricity counteracts the release action, preventing the spring clip from being released from the nozzle. After release, the static electricity can cause the clip to deviate from its intended position due to static attraction, resulting in missed placement or misalignment.

[0004] Current mainstream automation solutions, such as four-axis robotic arms, typically use a negative pressure nozzle at the end for suction. For smooth, ultra-thin springs, the effective contact area between the nozzle end and the spring is small, resulting in weak and potentially uneven suction. This can easily cause the spring to shift or fall off during acceleration / deceleration or vibration. These solutions rely primarily on shutting off negative pressure and / or applying brief positive pressure. Shutting off negative pressure cannot effectively overcome electrostatic suction forces, while applying air blows introduces strong, uncontrollable airflow, which can easily blow thin springs away or deflect them. This makes success difficult, especially in the presence of ambient airflow disturbances.

[0005] Therefore, a pre-oiling auxiliary device is needed to stably and accurately complete the removal and placement of shrapnel. Summary of the Invention

[0006] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a pre-oiling auxiliary device for placing thin and light spring pieces, which solves the problem that the existing extremely thin spring pieces are easily affected by airflow and static electricity during the placement process, resulting in inaccurate placement and installation positions of the spring pieces, and are prone to missing or crooked placement.

[0007] The purpose of the present invention can be achieved through the following technical solutions: A pre-oiling auxiliary device for placing thin spring pieces, comprising a manipulator, an oiling mechanism, a visual system, and a reflection analysis module; the oiling mechanism and the visual system are mounted on the manipulator, the manipulator is used to pick up and place the spring piece, and the oiling mechanism is used to perform oiling before placing the spring piece on a workpiece; The visual system includes an industrial camera, an annular coaxial light source and a polarizer; the industrial camera is arranged on the robot arm, the annular coaxial light source and the industrial camera are coaxially nested, and the polarizer is attached to the output surface of the light source; the industrial camera is connected to the reflective analysis module, and the captured image of the workpiece oiling is uploaded to the reflective analysis module; the reflective analysis module determines the effectiveness of the oiling by identifying the brightness enhancement characteristics of the oiling area relative to the oil-free area.

[0008] Preferably, the oil-spraying mechanism includes an oil tank, an oil pump, a nozzle and a control valve. The oil pump delivers the viscous oil in the oil tank to the nozzle, and the nozzle sprays oil onto the surface of the workpiece. The control valve is used to control the opening and closing of the nozzle.

[0009] Preferably, the viscous oil is a silicone-based viscous oil with titanium dioxide reflective particles added.

[0010] Preferably, a conical diffusion cavity is provided at the outlet end of the nozzle so that the sprayed oil point forms an annular convex structure with a thin center and thick edges, and the inclination angle of the conical diffusion cavity is 45°±5.

[0011] Preferably, the reflective light analysis module performs the following operations: Polarization difference processing: collects the reference image with the light source turned on and without polarization, and the characteristic image under the orthogonal polarization state, and generates a difference image; Feature area extraction: select the target oil area and adjacent oil-free area in the differential image; Brightness enhancement verification: When the average grayscale value of the oil-spotted area is greater than the average grayscale value of the adjacent oil-free area, it is determined that brightness enhancement exists.

[0012] Preferably, it also includes an intelligent oil quantity mapping controller, which pre-stores a three-dimensional mapping table of oil film area-injection quantity-adhesion force and executes: a) Based on the oil film area measured by the oil film reflection analysis module, the target fuel injection level is determined by querying the mapping table: small area → low fuel injection; medium area → medium fuel injection; large area → high fuel injection; b) Convert the injection quantity level to the control valve pulse width: low injection quantity → short pulse; medium injection quantity → medium pulse; high injection quantity → long pulse.

[0013] Preferably, the annular coaxial light source is a multi-spectrum tunable light source, including blue light and red light bands, and the contrast between the oil film and the background is optimized by switching the light source bands.

[0014] Preferably, it further comprises a pressure sensor and a state analysis unit provided on the manipulator; The pressure sensor is used to monitor the pressing force applied to the spring in real time when the spring is placed; The state analysis unit is connected to the industrial camera and the pressure sensor, and performs the following operations: a) when the pressing force reaches a preset pressure threshold, triggering the industrial camera to photograph the workpiece after the shrapnel is placed, to obtain an image of the shrapnel status; b) analyzing the shrapnel status image, identifying the edge features of the shrapnel and comparing them with the preset placement position to determine whether the shrapnel is positionally offset or warped; c) If the position offset or warping is detected to exceed the threshold, the current workpiece is marked as defective.

[0015] Preferably, the visual system further comprises a liquid lens module arranged in the optical path of the industrial camera, and the liquid lens module is regulated by voltage.

[0016] The beneficial effects of the present invention are: The adhesion force generated by the pre-oiling in this application solves the problem that thin and light springs are easily affected by airflow and static electricity, resulting in displacement, falling, and crooked placement, fundamentally improving the physical stability of placement. The optical analysis module detects the effectiveness of oiling in real time to ensure that the adhesion is reliable before each placement, avoiding placement problems caused by oiling failure, greatly reducing the risk of missing or crooked placement, effectively solving the core interference factors in the placement process and ensuring the quality of oiling, greatly reducing product defects or subsequent assembly failures caused by inaccurate position, missing, and crooked springs, and directly improving product yield and the overall reliability of the production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0018] Figure 1 This is a control schematic diagram of a pre-lighting auxiliary device provided in one embodiment of the present invention; Figure 2 This is a schematic structural diagram of a pre-lighting auxiliary device provided in one embodiment of the present invention; Figure 3 A schematic diagram of the structure of a visual system provided in one embodiment of the present invention; Legend: 1. Robot; 21. Nozzle; 3. Vision system; 31. Industrial camera; 32. Annular coaxial light source; 33. Polarizer. DETAILED DESCRIPTION

[0019] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0020] like Figure 1-Figure 3As shown, a pre-oiling auxiliary device for placing light and thin shrapnel includes a manipulator 1, an oiling mechanism, a visual system 3 and a reflection analysis module; the oiling mechanism and the visual system 3 are installed on the manipulator 1, the manipulator 1 is used to pick up and place the shrapnel, and the oiling mechanism is used to perform oiling before the shrapnel is placed on the workpiece; utilizing the physical properties of oil, before the shrapnel is placed at the target workpiece position, the oiling mechanism sprays a small amount of oil at the corresponding position of the target workpiece, and the oil film generates a slight adhesion force. When the manipulator 1 places the shrapnel at the target position, this layer of adhesion oil film can effectively increase the adhesion between the shrapnel and the workpiece surface, and prevent the shrapnel from being displaced by slight airflow. At the same time, the oil film, as a physical contact layer, helps to release or neutralize electrostatic charges, and reduce the problem of the shrapnel jumping, offsetting or adsorbing on the suction nozzle due to electrostatic repulsion / attraction.

[0021] Vision system 3 includes an industrial camera 31, an annular coaxial light source 32, and a polarizer 33. Industrial camera 31 is mounted on robot arm 1, coaxially nested with the annular coaxial light source 32, and polarizer 33 is attached to the output surface of the light source. Industrial camera 31 is connected to a reflective light analysis module, which uploads captured images of workpiece oil application to the module. The module determines the effectiveness of oil application by identifying the brightness enhancement of the oiled area relative to the oil-free area. The module exploits the phenomenon that oil films alter the optical reflectance properties of a surface. Under specific lighting conditions, the intensity and distribution of reflected light differ between the oiled area (oiled) and the oil-free area (substrate). Oil films typically create a smooth surface, resulting in more concentrated specular reflections, or alter diffuse reflection properties, resulting in higher local brightness in the processed image compared to the surrounding oil-free area. By determining whether the expected brightness enhancement pattern is present in the oiled area, the effectiveness of the oil application can be determined. If the oil application is ineffective, it is recorded as a defective rate and not assembled in the subsequent process, thereby achieving optimal processing quality.

[0022] In summary, the adhesion force generated by pre-oiling solves the problem that thin and light springs are easily affected by airflow and static electricity, resulting in displacement, falling, and crooked placement, fundamentally improving the physical stability of placement. The optical analysis module detects the effectiveness of oiling in real time to ensure that the adhesion is reliable before each placement, avoiding placement problems caused by oiling failure, greatly reducing the risk of missing or crooked placement, effectively solving the core interference factors in the placement process and ensuring the quality of oiling, greatly reducing product defects or subsequent assembly failures caused by inaccurate position, missing, and crooked springs, and directly improving product yield and the overall reliability of the production line.

[0023] In one embodiment, the oil injection mechanism includes an oil tank, an oil pump, a nozzle 21, and a control valve. The oil pump transfers viscous oil from the oil tank to the nozzle 21, and the nozzle 21 injects oil onto the surface of the workpiece. The control valve is used to control the opening and closing of the nozzle 21. The oil tank stores a sufficient amount of special viscous oil. The oil pump provides stable and adjustable pressure to extract the viscous oil from the oil tank and transfer it to the nozzle 21 pipeline. The nozzle 21 is the terminal component that performs the oil injection action. When the control valve is opened, high-pressure oil flows through the nozzle 21. When the oil flow is ejected from the tip of the nozzle 21 at high speed, its kinetic energy overcomes the surface tension and viscosity of the oil itself, forming a tiny oil droplet. The control valve is installed between the oil pump and the nozzle 21. After receiving the oil injection command signal, the solenoid valve coil is instantly energized, the valve core moves at high speed, and the oil channel is opened. The high-pressure oil flows through the valve to the nozzle 21, and the oil droplet begins to be injected.

[0024] In one embodiment, the viscous oil is a silicone-based viscous oil with titanium dioxide reflective particles added. The oil film alters the light reflectance properties of the workpiece. A smooth oil film produces stronger specular reflection than a rough or diffusely reflective surface without oil. The flaky particles in the silicone oil tend to align parallel to the workpiece's substrate surface, allowing the particles' flat surfaces to act like countless tiny mirrors, efficiently and directionally reflecting incident light back toward the light source and camera. Compared to spherical particles, flaky particles have a lower specific surface area and more regular reflective surface, reducing diffuse scattering and concentrating reflected light.

[0025] In summary, by adding reflective titanium dioxide particles to silicone-based viscous oil, the pre-oiling assist device upgrades its oiling effectiveness detection principle from relying on brightness changes caused by the oil film's own weak specular reflection to detecting the significant brightening mark formed by the directional arrangement of highly reflective particles. This design actively enhances the optical signal being detected, comprehensively improving detection reliability, accuracy, speed, and anti-interference capabilities. This allows the "reflection analysis module" to more accurately determine the effectiveness of oiling, further ensuring the precision of thin shrapnel placement and the yield rate of the entire production process.

[0026] In one embodiment, a conical diffusion chamber is provided at the outlet end of the nozzle 21, so that the sprayed oil point forms an annular convex structure with a thin center and thick edges. The inclination angle of the conical diffusion chamber is 45°±5. When the viscous oil flows through the end of the nozzle 21 at high speed under pressure, it suddenly encounters the conical diffusion chamber with a 45° inclination angle. According to the principles of fluid dynamics, the conical chamber causes the oil flow to suddenly enter the open space from the narrow outlet, causing the flow rate to drop sharply and the pressure to be released. The oil diffuses radially along the inclination angle of the cone surface, forming a thin laminar flow that spreads out in all directions. The wetting effect between the viscous oil and the conical cavity wall generates adhesion, further pushing the oil to move along the outer edge of the cone surface. The central part of the oil flow continues to move forward due to inertia, but lacks the support of the cavity wall. Under the action of gravity and surface tension, it quickly collapses and becomes thinner, forming a depression. When the oil reaches the edge of the conical cavity, it is constrained by the balance of the gas-liquid-solid three-phase interface tension, and the contact line is confined to the edge corners. Subsequent oil is continuously transported, accumulating to form a thick annular convex structure. Due to the thick oil film in the annular raised area, a dense reflective layer is formed at the edge, appearing as a bright white high-contrast circular ring under polarized light imaging. The thin oil area in the center reflects extremely weak light, forming a clear dark center in the image, which constitutes a "light and dark dual feature" with the bright ring, providing accurate positioning of the target for the visual system 3.

[0027] In one embodiment, the reflective light analysis module performs the following operations: Polarization difference processing: collects the reference image with the light source turned on and without polarization, and the characteristic image under the orthogonal polarization state, and generates a difference image; Feature area extraction: select the target oil area and adjacent oil-free area in the differential image; Brightness enhancement verification: When the average gray value of the oil-dot area is greater than the average gray value of the adjacent oil-free area, it is determined that there is brightness enhancement. The microparticle oil film produces depolarized reflection, and the grayscale value in the differential image is significantly higher than that of the oil-free area, deeply integrating optical physical properties with intelligent algorithms.

[0028] In one embodiment, an intelligent oil quantity mapping controller is further included, which pre-stores a three-dimensional mapping table of oil film area, oil injection quantity, and adhesion force, and executes: the mapping table is established through a large amount of experimental, simulation, or empirical data, and records the optimal oil injection quantity required to achieve the best adhesion effect under a specific oil film area, taking into account the effects of various factors on adhesion, such as lubricant properties, surface conditions, and temperature; a) Based on the oil film area measured by the oil film reflection analysis module, a mapping table is consulted to determine the target fuel injection rate level: small area → low fuel injection rate; medium area → medium fuel injection rate; large area → high fuel injection rate. The oil film reflection analysis module monitors the state of the lubrication surface in real time, specifically measuring the area of ​​the currently formed lubricating oil film, and transmits these measurement results to the intelligent fuel quantity mapping controller in real time; b) Convert the fuel injection level to the pulse width of the control valve. The fuel injection valve is usually controlled by an electrical pulse signal. The pulse width directly determines the length of time the valve is open, and thus determines the final amount of fuel injected: low fuel injection → short pulse; medium fuel injection → medium pulse; high fuel injection → long pulse; The intelligent oil quantity mapping controller uses the oil film area measured by the reflective analysis module to query the optimal injection parameters through a three-dimensional mapping table: oil film area-injection quantity-adhesion force. For example, a low injection quantity is used for a small oil film area to prevent oil diffusion, while a high injection quantity is used for a large oil film area to ensure coverage integrity. Fixed injection quantities or simple open-loop control are no longer used. The injection quantity can be dynamically adjusted according to actual lubrication needs. This reduces unnecessary lubricant consumption and potential contamination while ensuring that key components are fully lubricated, helping to improve overall equipment efficiency and operational reliability.

[0029] In one embodiment, the annular coaxial light source 32 is a multi-spectral tunable light source, which includes blue and red light bands. The contrast between the oil film and the background is optimized by switching the light source bands. The multi-spectral tunable light source achieves dynamic optimization of the contrast between the oil film and the background through the synergistic effect of blue light and red light. The working principle is based on the difference in optical properties of the two bands, which respectively enhances the surface reflection of the oil film and the details of the workpiece, thereby improving the detection accuracy and equipment adaptability, and providing support for the high-precision placement of thin and light springs.

[0030] In one embodiment, it further includes a pressure sensor and a state analysis unit provided on the manipulator 1; The pressure sensor is used to monitor the pressing force applied to the spring piece in real time when placing it. It also monitors the pressing force value at the end of the robot 1 in real time, converting the physical assembly force into an electrical signal. This provides a dynamic benchmark for triggering detection and solves the problem of missed detection caused by traditional fixed-time sequence photography. The state analysis unit serves as the data processing core and establishes the linkage logic between the pressure signal and visual detection. The state analysis unit is connected to the industrial camera 31 and the pressure sensor and performs the following operations: a) When the pressing force reaches a preset pressure threshold, the industrial camera 31 is triggered to capture an image of the workpiece after the spring clip is placed, obtaining an image of the spring clip's status. When the pressure value is greater than the threshold, it indicates that the spring clip has stably contacted the workpiece surface. This allows for accurate detection without image blurring caused by vibration of the robotic arm. b) Analyze the fragment status image, extract the coordinates of the fragment outline corner points, calculate the Euclidean distance to the preset reference position, calculate the deformation amount through the warping angle, and convert the subjective visual inspection into an objective quantitative indicator; c) If it is identified that the position offset or warpage exceeds the threshold, based on the offset / warpage out-of-tolerance result, it is marked as a defective product so that the current workpiece will not be assembled in the next process assembly.

[0031] In one embodiment, the visual system 3 also includes a liquid lens module arranged in the optical path of the industrial camera 31. The liquid lens module is regulated by voltage, and the liquid surface curvature is adjusted by changing the voltage of the liquid lens electrode to achieve rapid zoom. During the placement of the shrapnel, the lens first shoots the oil-dot area in telephoto mode, and then switches to short-focus mode to detect the edge details of the shrapnel. Dynamic focusing eliminates vibration interference caused by mechanical movement and improves image clarity.

[0032] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A pre-oiling auxiliary device for placing thin springs, characterized in that: It includes a manipulator, an oiling mechanism, a visual system and a reflection analysis module; the oiling mechanism and the visual system are installed on the manipulator, the manipulator is used to take and place the shrapnel, and the oiling mechanism is used to perform oiling before placing the shrapnel on the workpiece; The visual system includes an industrial camera, an annular coaxial light source and a polarizer; the industrial camera is arranged on the robot arm, the annular coaxial light source and the industrial camera are coaxially nested, and the polarizer is attached to the output surface of the light source; the industrial camera is connected to the reflective analysis module, and the captured image of the workpiece oiling is uploaded to the reflective analysis module; the reflective analysis module determines the effectiveness of the oiling by identifying the brightness enhancement characteristics of the oiling area relative to the oil-free area.

2. A pre-oiling auxiliary device for placing thin spring pieces according to claim 1, characterized in that: The oil-spraying mechanism includes an oil tank, an oil pump, a nozzle and a control valve. The oil pump delivers the viscous oil in the oil tank to the nozzle, and the nozzle sprays oil onto the surface of the workpiece. The control valve is used to control the opening and closing of the nozzle.

3. A pre-oiling auxiliary device for placing thin spring pieces according to claim 2, characterized in that: The viscous oil is a silicone-based viscous oil with titanium dioxide reflective particles added.

4. The pre-oiling auxiliary device for placing thin spring pieces according to claim 2, characterized in that: The outlet end of the nozzle is provided with a conical diffusion cavity, so that the sprayed oil point forms an annular convex structure with a thin center and thick edges. The inclination angle of the conical diffusion cavity is 45°±5.

5. The pre-oiling auxiliary device for placing thin spring pieces according to claim 1, characterized in that: The reflection analysis module performs the following operations: Polarization difference processing: collects the reference image with the light source turned on and without polarization, and the characteristic image under the orthogonal polarization state, and generates a difference image; Feature area extraction: select the target oil area and adjacent oil-free area in the differential image; Brightness enhancement verification: When the average grayscale value of the oil-spotted area is greater than the average grayscale value of the adjacent oil-free area, it is determined that brightness enhancement exists.

6. The pre-oiling auxiliary device for placing thin spring pieces according to claim 5, characterized in that: It also includes an intelligent fuel quantity mapping controller, which pre-stores a three-dimensional mapping table of oil film area, fuel injection quantity, and adhesion force, and performs the following operations: a) based on the oil film area measured by the oil film reflection analysis module, querying the mapping table to determine the target fuel injection quantity level: small area → low fuel injection quantity; medium area → medium fuel injection quantity; large area → high fuel injection quantity; b) Convert the injection quantity level to the control valve pulse width: low injection quantity → short pulse; medium injection quantity → medium pulse; high injection quantity → long pulse.

7. The pre-oiling auxiliary device for placing light and thin spring pieces according to claim 1, characterized in that: The annular coaxial light source is a multi-spectrum tunable light source, including blue light and red light bands, and the contrast between the oil film and the background is optimized by switching the light source bands.

8. The pre-oiling auxiliary device for placing thin spring pieces according to claim 1, characterized in that: It also includes a pressure sensor and a state analysis unit arranged on the manipulator; the pressure sensor is used to monitor the pressing force applied to the shrapnel in real time when placing the shrapnel; the state analysis unit is connected to the industrial camera and the pressure sensor, and performs the following operations: a) When the pressing force reaches a preset pressure threshold, the industrial camera is triggered to take a picture of the workpiece after the shrapnel is placed, and obtain a shrapnel state image; b) The shrapnel state image is analyzed, the edge features of the shrapnel are identified and compared with the preset placement position to determine whether the shrapnel has position offset or warping; c) If it is identified that the position offset or warping exceeds the threshold, the current workpiece is marked as unqualified.

9. The pre-oiling auxiliary device for placing thin spring pieces according to claim 1, characterized in that: The visual system further includes a liquid lens module arranged in the optical path of the industrial camera, and the liquid lens module is regulated by voltage.

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