A visual inspection system and method for automatically detecting the fit of connecting rod bushings

Abstract

The present invention provides a visual inspection system and method for automatically detecting the fit of connecting rod bushings, comprising a conveyor belt, a first connecting rod clamp, a second connecting rod clamp, a clamping arm, a turntable and a laser locator. The mounting groove on the right side of the conveyor belt is connected to the second connecting rod clamp, an industrial camera group is fixedly mounted on one end of the industrial camera support rod, and the laser locator is arranged at the front end of the first connecting rod clamp, the front end of the second connecting rod clamp and the front end of the connecting rod clamping head are all connected to the laser locator. The machine vision inspection device proposed in the present invention has low cost, low working environment requirements, and occupies little working space. The inspection accuracy can reach the required accuracy for the fitting of the connecting rod small head hole bushing under the National VI automobile standard, and is more adapted to the requirements of industrial production in the new era, making the connecting rod bushing fitting detection more efficient, solving the detection problems encountered by production enterprises, and ensuring that the connecting rod bushing fitting detection meets the production accuracy requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of visual inspection, and relates to a visual inspection system and method for automatically inspecting the fit of a connecting rod bushing. Background Art

[0002] As a critical component of automotive engines, connecting rods are subject to high cyclic loads and complex forces during operation, placing high demands on connecting rod assembly. After a series of cleaning processes, the cleanliness of the connecting rod surface and crevices is improved. However, areas requiring higher standards of cleanliness, such as the connecting rod bushing, may not meet the required standards. If residual metal debris and anti-rust oil contamination exceed the standard, they can easily scratch the inner surface of the connecting rod bushing, which requires extremely high precision, and also hinder heat transfer during operation, seriously affecting the performance of the connecting rod after assembly with the engine and crankshaft. Therefore, connecting rods must undergo a series of tests before leaving the factory to ensure that the cleanliness of the connecting rod bushing meets the standard and the fit is within the normal range.

[0003] Machine vision is a comprehensive technology that encompasses image processing, mechanical engineering, control, electric lighting, optical imaging, sensors, analog and digital video technology, and computer hardware and software (image enhancement and analysis algorithms, image cards, I / O cards, etc.). Machine vision products (i.e., image capture devices, available in CMOS and CCD) convert captured objects into image signals, which are then transmitted to a dedicated image processing system. This system then obtains the object's morphological information and converts it into a digitized signal based on pixel distribution, brightness, color, and other information. The imaging system then performs various operations on these signals to extract the target's features.

[0004] Currently in the industrial field, due to the high precision requirements of the National VI automobile standard for automobile parts, especially in the precision detection of the fitting accuracy of the connecting rod small head hole bushing, traditional manual visual inspection has low accuracy, high cost, and slow detection efficiency. Although ultrasonic testing has high detection accuracy, it is too costly, the detection equipment is fragile, and the working environment required is harsh, which cannot meet the needs of industrial production. Summary of the Invention

[0005] The purpose of the present invention is to provide a visual inspection system and method for automatically detecting the fit of connecting rod bushings, so as to solve the problems proposed in the above background technology of realizing an automated machine vision inspection process and minimizing the impact of low accuracy, high cost and slow inspection efficiency of manual inspection.

[0006] The objectives of the present invention can be achieved through the following technical solutions: A visual inspection system for detecting the fit of a connecting rod bushing, comprising a conveyor belt, a first connecting rod clamp, a second connecting rod clamp, a clamping arm rod, a turntable and a laser locator, wherein the mounting slot on the left side of the conveyor belt is installed and connected to the first connecting rod clamp, and the mounting slot on the right side of the conveyor belt is installed and connected to the second connecting rod clamp, one end of the industrial camera support rod is fixedly installed with an industrial camera group, and the industrial camera group corresponds to the first connecting rod clamp and the second connecting rod clamp, the bottom end of the turntable is fixedly installed with a supporting long rod, both ends of the turntable are fixedly installed with extension arms, one end of the two extension arms are fixedly installed with lifting rods, one end of the two lifting rods are fixedly installed with a connecting rod clamping head, and the interior of the two connecting rod clamping heads are installed with limiting clamps, and the laser locator is arranged at the front end of the first connecting rod clamp, and the front end of the second connecting rod clamp and the front end of the connecting rod clamping head are all connected to the laser locator.

[0007] A method for detecting the fit of a connecting rod bushing using a visual inspection system comprises the following steps:

[0008] S1: After the connecting rod slot is placed on the conveyor belt, the conveyor belt's motor drives the belt to move, causing the connecting rod slot to move forward;

[0009] S2: When the laser locator at the front end of the first connecting rod fixture detects the connecting rod slot, the first and second connecting rod fixtures will clamp the connecting rod slot and lift it up. The visual processor of the industrial camera group starts working to detect the fit of the bushing in the small end hole of the connecting rod.

[0010] S3: If the bushing fit is accurate, it is judged as passed, and the drive device built into the turntable is not powered on; if it is not accurate, the first connecting rod clamp and the second connecting rod clamp lower the connecting rod slot, and the conveyor belt continues to drive the connecting rod slot forward. At this time, the drive device built into the turntable is powered on, and when passing through the connecting rod clamping head, the connecting rod clamping head will clamp the connecting rod slot, and the turntable will rotate to place the connecting rod slot at the unqualified connecting rod, waiting for the next step of processing.

[0011] The base of the industrial camera support rod is a control box, and a visual processor is installed inside the control box, and the visual processor is electrically connected to the industrial camera group; a reduction motor is fixedly installed inside the turntable, and the output shaft of the reduction motor is fixedly connected to the two extension arms.

[0012] Compared with the existing technology, the advantages of the visual inspection system and method for automatically detecting the fitting degree of connecting rod bushings of the present invention are as follows: the machine vision inspection device proposed by the present invention has low cost, low working environment requirements, and occupies less working space. The detection accuracy can reach the required accuracy for the fitting degree of the connecting rod small head hole bushing under the National VI automobile standard, which is more adapted to the requirements of industrial production in the new era, making the connecting rod bushing fitting degree detection more efficient, solving the detection problems encountered by production enterprises, and making the connecting rod bushing fitting degree detection meet the production accuracy requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The diagram is a top view of a visual inspection system and method for automatically inspecting the fit of a connecting rod bushing according to the present invention.

[0014] Figure 2 It is a schematic diagram (main view) of a connecting rod clamping head of a recovery device portion of a visual inspection system and method for automatically detecting the fit of a connecting rod bushing according to the present invention.

[0015] Figure 3 The present invention is a schematic diagram of the workflow of a visual inspection system and method for automatically detecting the fitting degree of a connecting rod bushing.

[0016] Figure 4 This is an industrial camera group (main view) of a visual inspection system and method for automatically detecting the fit of a connecting rod bushing according to the present invention.

[0017] Figure 5 The present invention relates to an industrial camera group (locked state) of a visual inspection system and method for automatically detecting the fitting degree of a connecting rod bushing.

[0018] Figure 6 The present invention relates to an industrial camera group (in an open state) of a visual inspection system and method for automatically detecting the fitting degree of a connecting rod bushing.

[0019] In the figure, 1. Conveyor belt; 2. First connecting rod clamp; 3. Second connecting rod clamp; 4. Industrial camera group; 5. Industrial camera support rod; 6. Turntable; 7. Extension arm; 8. Connecting rod clamping head; 9. Lifting rod; 10. Limit clamp; 11. Support long rod; 12. Laser locator. DETAILED DESCRIPTION

[0020] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0021] like Figure 1 、 Figure 2 and Figure 3As shown, it includes a conveyor belt 1, a laser locator 12, a detection device (connecting rod clamp) 3, an industrial camera support rod 5 (the base of which is a control box, and a visual processor is installed inside the control box, and the visual processor is electrically connected to the machine vision detection equipment) and a turntable 6 (a reduction motor is fixedly installed inside, and the output shaft of the reduction motor is fixedly connected to two extension arms 7). The left side of the conveyor belt 1 is fitted with the connecting rod clamp 2 (the front end of which has a laser locator 12), and the installation groove on the right side of the conveyor belt 1 is fitted with the connecting rod clamp 3 (the front end of which has a laser locator 12) , together constituting the detection part; an industrial camera group 4 is fixedly installed at one end of the industrial camera support rod 5, the industrial camera group 4 corresponds to the laser locator 12 and the detection device (connecting rod clamp) 3, and a supporting long rod 11 is fixedly installed at the bottom end of the turntable 6, and extension arms 7 are fixedly installed at both ends of the turntable 6, and support rods 9 are fixedly installed at one end of the two extension arms 7, and connecting rod clamping heads 8 are fixedly installed at one end of the two support rods 9, and the laser locator is arranged at the front end of the first connecting rod clamp, and the front end of the second connecting rod clamp and the front end of the connecting rod clamping head are all connected to the laser locator 12.

[0022] Specifically, since the cameras and machine vision lenses inside the industrial camera group 4 are important in function and relatively fragile in structure, a protective device is designed at the working position to protect them. During operation, the protective device can be opened by an external controller, and the internal cameras and machine vision lenses can be ejected from the protective device (i.e., in the open state). During non-operation, the internal cameras and machine vision lenses can be returned to the interior of the industrial camera group 4 by an external controller or manual operation, and the protective device is closed, making the internal cameras and machine vision lenses of the industrial camera group 4 less susceptible to damage by collision with external objects (i.e., in the locked state).

[0023] To achieve the required accuracy of industrial camera group 4, each component of industrial camera group 4 uses a CMOS area array industrial camera, combined with a coaxial parallel LED light source, a machine vision lens, an image acquisition card, and a vision processor for detection. This ensures accuracy while minimizing the cost of use and increasing the service life. In terms of operators, a weighted median filter operator is used to process the image and an illuminate operator is used. When the factor coefficient is 0.8 (because the foreground and background are clearly distinguished after processing, it is easy to extract feature information), the spoke operator is finally referred to (which can find the fitting circle of the curvature radius and measure the size of the curvature radius) to obtain an operator that can calculate the fit of the connecting rod bushing.

[0024] Among them: the detection basis of the laser locator 12 is to judge whether the connecting rod reaches the specified position through laser. If so, the device works, otherwise it triggers an alarm; after the device is completed, the laser detects whether the connecting rod is still on the device after a certain period of time to judge whether the device is working normally.

[0025] The following steps are involved:

[0026] S1: After the connecting rod assembly groove is placed on the conveyor belt 1, the motor device of the conveyor belt 1 drives the belt to move, causing the connecting rod assembly groove to move forward;

[0027] S2 When the laser locator 12 detects the connecting rod assembly groove, the first connecting rod clamp 2 and the second connecting rod clamp 3 (clamps with grooves that match the connecting rod assembly groove) will clamp the connecting rod assembly groove and lift it up (at this time, the outer frames of the first connecting rod clamp 2 and the second connecting rod clamp 3 are stationary, and the inner clamps are lifted up), and the visual device of the industrial camera group 4 starts working to detect the fit of the bushing in the small head hole of the connecting rod;

[0028] S3: If the bushing fit is accurate, it is judged as passed, and the built-in driving device of the turntable 6 is not powered on; if it is not accurate, the second connecting rod clamp 3 puts down the connecting rod assembly groove, and the conveyor belt 1 continues to drive the connecting rod assembly groove to move forward. At this time, the built-in driving device of the turntable 6 is powered on. When passing through the laser locator 12, the connecting rod clamping head 8 will clamp the connecting rod assembly groove, and its internal clamp will clamp and lift the connecting rod assembly groove. The turntable 6 rotates to above the buffer recovery solution (that is, the other side parallel to the conveyor belt), and the internal clamp retracts the external frame of the connecting rod clamping head 8, so that the connecting rod assembly groove freely falls into the unqualified connecting rod part (buffer recovery solution) and waits for the next step of processing.

[0029] In addition, by collecting the detection time data of the connecting rod bushing and the time data of the connecting rod entering the detection device and the recovery device, the turntable rotation speed and the conveyor belt feed speed are planned to ensure maximum work efficiency; by modifying the conveyor belt surface, the connecting rod can be automatically transported on the conveyor belt, and there are the following solutions: connecting rod assembly groove; the connecting rod assembly groove is used to assemble the connecting rod as a whole, and its bottom has a groove that matches the conveyor belt, so that it can run to the designated position (such as the detection device and the recovery device) without error with the conveyor belt; there are grooves on its side that match the fixtures of the detection device and the recovery device, so that it can move up and down with the fixture for machine vision inspection and recovery.

[0030] Setting time period description

[0031] Each time period refers to the time period within the same process, and an appropriate error range needs to be set for each time period;

[0032] Set time period 1: the time required for the connecting rod assembly groove to reach the specified position of the detection device;

[0033] Set time period 2: the time required for the detection device fixture to clamp the connecting rod assembly groove and rise to the top;

[0034] Set time period 3: the time required for the detection device fixture to descend, place the connecting rod assembly groove on the conveyor belt, and reset the fixture;

[0035] Set time period 4: the time required for the connecting rod assembly slot to reach the recovery device from the detection device location;

[0036] Set time period 5: the time required for the recovery device fixture to grasp the connecting rod assembly slot and rotate it to the top of the recovery tank;

[0037] Set time period 6: the time required for the recovery device fixture to release the connecting rod assembly groove.

[0038] 3. Fault Analysis

[0039] Conveyor belt failure: conveyor belt is stuck, conveyor belt is reversed;

[0040] Laser positioning device failure: the laser cannot be emitted normally, and the laser emission angle deviation is too large;

[0041] Failure of the detection device: the device cannot be lifted or lowered normally, the clamp is loose, causing the clamping connecting rod assembly groove to fall off;

[0042] Recovery device failure: the device cannot rotate, the fixture is loose, causing the connecting rod assembly slot to fall off, and the fixture is stuck, making it impossible to release the connecting rod assembly slot;

[0043] System communication failure: Communication abnormality causes the device to be unable to receive instructions normally.

[0044] 4. Analysis of alarm causes at each location

[0045] The laser locator 12 does not detect the connecting rod assembly groove within the set time period 1

[0046] Conveyor belt failure, connecting rod assembly groove does not reach the specified position

[0047] The laser locator is faulty and the connecting rod assembly groove is not detected normally.

[0048] The laser positioning device 12 detects the connecting rod assembly groove after the set time period 2

[0049] The detection device is faulty, the connecting rod assembly slot is not lifted up or falls off during lifting.

[0050] The laser positioning device is faulty, the laser angle is offset, and the upper connecting rod assembly slot is incorrectly detected.

[0051] The laser locator 12 does not detect the connecting rod assembly groove after the set time period 3

[0052] The detection device is faulty and the connecting rod assembly slot is not lowered onto the conveyor belt.

[0053] The laser locator is faulty and the connecting rod assembly groove is not detected normally.

[0054] The laser locator 12 does not detect the connecting rod assembly groove after the set time period 4

[0055] Conveyor belt failure, connecting rod assembly groove does not reach the specified position

[0056] The laser locator is faulty and the connecting rod assembly groove is not detected normally.

[0057] Laser locator 12 does not detect the connecting rod assembly groove

[0058] Conveyor belt failure, connecting rod assembly groove does not reach the specified position

[0059] The laser locator is faulty and the connecting rod assembly groove is not detected normally.

[0060] The laser locator 12 does not detect the connecting rod assembly groove within the set time period 5

[0061] The recovery device fails and the connecting rod assembly groove falls off during movement

[0062] The laser locator is faulty and the connecting rod assembly groove is not detected normally.

[0063] The laser locator 12 detects the connecting rod assembly groove after the set time period 6

[0064] The recovery device fails and the clamp cannot release the connecting rod assembly groove

[0065] System communication failure

[0066] System communication failure will cause the device to not receive instructions and cannot operate normally. The initial idea is to set up a laser locator to detect whether the connecting rod assembly slot passes through the specified position during an abnormal time period (or does not pass through the specified position within the specified time period) to issue an alarm, and use the upper computer to monitor the working status of each device in real time to identify the location where the communication problem occurs.

[0067] Description: The laser detector uses laser to determine whether the connecting rod reaches the specified position. If so, the device works, otherwise it triggers an alarm. After the device is completed, the laser detects whether the connecting rod is still on the device after a certain period of time to determine whether the device is working properly.

[0068] Matters not described in detail in this specification constitute prior art known to those skilled in the art. The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

Claims

1. A method for automatically detecting the fit of a connecting rod bushing using a visual inspection system, characterized in that: The following steps are involved: S1: After the connecting rod slot is placed on the conveyor belt (1), the motor device of the conveyor belt (1) drives the belt to move, causing the connecting rod slot to move forward; S2: When the laser locator (12) at the front end of the first connecting rod clamp (2) detects the connecting rod groove, the first connecting rod clamp (2) and the second connecting rod clamp (3) will clamp the connecting rod groove and lift it up, and the visual processor of the industrial camera group (4) will start working to detect the fitting degree of the bushing of the small head hole of the connecting rod; S3: If the bushing fit is accurate, it is judged as passed, and the driving device built into the turntable (6) is not powered on; if it is not accurate, the first connecting rod clamp (2) and the second connecting rod clamp (3) lower the connecting rod groove, and the conveyor belt (1) continues to drive the connecting rod groove to move forward. At this time, the driving device built into the turntable (6) is powered on, and when passing through the connecting rod clamping head (8), the connecting rod clamping head (8) will clamp the connecting rod groove, and the turntable (6) will rotate to place the connecting rod groove at the unqualified connecting rod, waiting for the next step of processing; A visual inspection system for automatically detecting the fitting degree of a connecting rod bushing comprises a conveyor belt (1), a first connecting rod clamp (2), a second connecting rod clamp (3), an industrial camera support rod (5), a turntable (6) and a laser locator (12), wherein the conveyor belt (1) is connected to the first connecting rod clamp (2) at the installation groove on the left side, the conveyor belt (1) is connected to the second connecting rod clamp (3) at the installation groove on the right side, and an industrial camera assembly is fixedly installed on one end of the industrial camera support rod (5). (4), the industrial camera group (4) corresponds to the first connecting rod clamp (2) and the second connecting rod clamp (3), the bottom end of the turntable (6) is fixedly installed with a supporting long rod (11), both ends of the turntable (6) are fixedly installed with extension arms (7), one end of the two extension arms (7) is fixedly installed with a lifting rod (9), one end of the two lifting rods (9) is fixedly installed with a connecting rod clamping head (8), and the interior of the two connecting rod clamping heads (8) is installed with a limiting clamping block (10).

2. The method of a visual inspection system for automatically detecting the fitting degree of a connecting rod bushing according to claim 1, characterized in that: The base of the industrial camera support rod (5) is a control box, and a visual processor is installed inside the control box, and the visual processor is electrically connected to the industrial camera group (4); a reduction motor is fixedly installed inside the turntable (6), and the output shaft of the reduction motor is fixedly connected to the two extension arms (7).

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