A machine vision detection mechanism and detection method for engine crankshaft journal defects

Abstract

The present invention discloses a machine vision inspection mechanism and inspection method for engine crankshaft journal defects, comprising an inspection room, a production line and an NG line, wherein a CCD inspection group and a robot are installed inside the inspection room, a clamping claw assembly is installed at the mobile end of the robot, and the clamping claw assembly comprises a main frame, the middle part of the top wall of the main frame is connected to the mobile end of the robot, cylinders are installed at the top walls of the left and right parts of the main frame, and clamping claws are installed at the piston ends of the cylinders. The present invention stops the crankshaft on the crankshaft support by using a CCD camera and a pneumatic stopper, and then quickly clamps the crankshaft by cooperating with the clamping claw assembly and the robot, and utilizes the CCD camera and the inspection port of the CCD inspection group to quickly capture each crankshaft journal and maintain image consistency.

Description

Technical Field

[0001] The present invention belongs to a technology that combines machine vision technology, automation system and robot system, and is applied to the field of automobile engine crankshaft and camshaft detection. Background Art

[0002] In the production of automotive engine crankshafts, defect detection for surface scratches, cracks, chipped corners, and broken edges plays a crucial role in the quality of the entire vehicle. For example, a 0.3mm diameter sand hole can cause engine malfunction. Therefore, crankshaft defect detection is of great significance to the product itself.

[0003] At present, defect detection of engine crankshafts in China relies on manual visual inspection. This method is too time-consuming (a skilled worker needs 5 minutes to fully inspect a product) and prone to omissions. In addition, the crankshaft itself is relatively heavy, and workers will also become fatigued during long periods of manual inspection, resulting in the flow of incorrect products into the next process, seriously affecting the safety and quality of the vehicle, and reducing the overall production efficiency and increasing the error rate.

[0004] At present, there is no mature crankshaft defect detection equipment at home and abroad. The reasons are:

[0005] (1) The crankshaft structure is very complex. The crankshaft has 10-12 shafts that are not centered on one axis. Each shaft requires 360-degree inspection.

[0006] (2) The reflective arc surface of each shaft makes it very difficult to capture images. In addition, the crankshafts coming out of the previous process on the production line contain a mixture of oil and water, which also makes it difficult to capture images.

[0007] (3) Heavy weight and complex structure. All axial surfaces must be protected from secondary damage, which makes it difficult to grasp and flip.

[0008] (4) High detection accuracy is required. The industry standard requires a detection accuracy of 0.05mm.

[0009] Therefore, to overcome the above difficulties, it is necessary to solve the problem of rapid automatic positioning and grasping of the engine crankshaft, rapid imaging of each crankshaft journal and maintaining image consistency. Based on this, the present invention designs a machine vision detection mechanism for engine crankshaft journal defects to solve the above problems. Summary of the Invention

[0010] The purpose of the present invention is to provide a machine vision detection mechanism for engine crankshaft journal defects to solve the problem raised in the above background technology of how to quickly and automatically locate and grasp the engine crankshaft, quickly photograph each crankshaft journal and maintain image consistency.

[0011] To achieve the above objectives, the present invention provides the following technical solutions: a machine vision inspection mechanism for engine crankshaft journal defects, comprising an inspection room, a production line, and an NG line; a CCD inspection group and a robot are installed inside the inspection room; a gripper assembly is installed on the mobile end of the robot;

[0012] The clamping jaw assembly includes a main frame, the middle part of the top wall of the main frame is connected to the moving end of the robot, the top walls of the left and right parts of the main frame are both equipped with cylinders, the piston end of the cylinder is equipped with a clamping jaw, the clamping jaw passes through the upper and lower parts of the main frame, the upper inner wall of the right clamping jaw is equipped with a driving motor, the output end of the driving motor passes through the right clamping jaw, the output end of the driving motor and the right wall of the lower part of the right clamping jaw are both equipped with pulleys, a chuck is installed on the left side of the lower pulley, and the chuck is located on the left side of the right clamping jaw, and a belt is connected between the two groups of pulleys.

[0013] Preferably, the production line passes through the inner space of the inspection room, the starting end of the NG line is located in the inner space of the inspection room, and the NG line is arranged in parallel with the production line.

[0014] Preferably, a pneumatic stopper is provided on the path of the production line, and crankshaft supports are evenly placed on both the production line and the NG line.

[0015] Preferably, a crankshaft is placed on the crankshaft support, and both ends of the crankshaft are respectively facing the two sides of the production line or the NG line.

[0016] Preferably, the bottom wall of the robot is installed on the bottom wall inside the inspection room, and the robot is located on the middle line between the production line and the NG line.

[0017] Preferably, CCD cameras are installed on both sides of the production line within the range of movement of the robot, and the CCD cameras are arranged symmetrically.

[0018] Preferably, the robot is located directly in front of the detection port of the CCD detection group.

[0019] The present invention discloses a machine vision inspection method for engine crankshaft journal defects. The crankshaft product flows into the production line to be inspected on the crankshaft support. After the crankshaft support passes through the clamping and positioning area of the robot, the pneumatic stopper accurately positions the crankshaft support.

[0020] The sensor on the pneumatic stopper sends a detection signal to the crankshaft end face detection CCD, which detects defects on both ends and locates the axial angle, so that the robot can adjust the chuck on the rotating jaw. After the crankshaft end face detection CCD completes the acquisition, the axial angle θ and the X-axis offset ΔX are communicated to the robot. The chuck on the robot's rotating jaw rotates to the above angle θ and then moves to the grasping position according to the ΔX correction amount. The crankshaft is grasped.

[0021] Furthermore, the robot grabs the crankshaft through the gripper assembly. Under the high-speed camera at the inspection port of the CCD inspection group, for each main journal, the distance between the lens and the photographed surface is constant during the rotation of the crankshaft. For the four connecting rod journals on both sides, the distance between the lens and the photographed surface is constantly changing during the shooting process. The robot cooperates with the camera to achieve a constant working distance and adjusts the photo acquisition image according to the forward and backward movement of the crankshaft in the focal plane. Each product has three axis detection positions, a total of 10 cams, and each cam takes a circle. The number of cams distributed on the axis from left to right is 2, 6, and 2 arrays. Each product takes images ten times. Each time the robot moves, it sends a shooting signal to the CCD camera. The camera receives the shooting signal of the robot and performs rapid defect analysis on each sub-image of the current product. When defect features appear, the features are recorded and the results are sent to the PLC system while recording this position. After the robot obtains the inspection conclusion, it puts the crankshaft back to the original production line or the NG line.

[0022] Compared with the prior art, the present invention has the following advantages: The present invention utilizes a CCD camera and a pneumatic stopper to stop the crankshaft on the crankshaft support. The gripper assembly and the robot then cooperate to quickly clamp the crankshaft. The CCD camera and the inspection port of the CCD inspection group can quickly capture each crankshaft journal and maintain image consistency. Of course, any product implementing the present invention does not necessarily need to simultaneously achieve all of the aforementioned advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a schematic diagram of the structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the partial structure of the back of the present invention;

[0026] Figure 3 This is a schematic diagram of the internal mechanical structure of the detection chamber of the present invention;

[0027] Figure 4 This is a schematic diagram of the robot grasping the Figure 1 ;

[0028] Figure 5 This is a schematic diagram of the robot grasping the Figure 2 ;

[0029] Figure 6 For the present invention Figure 1 A magnified view of point A;

[0030] Figure 7 It is a flow chart of the present invention.

[0031] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0032] 100-Inspection room, 200-Production line, 300-NG line, 400-CCD inspection group, 500-Robot, 600-Gripper assembly, 610-Main frame, 620-Cylinder, 630-Gripper, 640-Drive motor, 650-Belt, 700-Crankshaft support, 800-CCD camera, 900-Crankshaft, 001-Pneumatic stopper. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] See also Figure 1-7 The present invention provides a technical solution: a machine vision inspection mechanism for engine crankshaft journal defects, comprising an inspection room 100, a production line 200, and an NG line 300. A CCD inspection group 400 and a robot 500 are installed inside the inspection room 100, and a gripper assembly 600 is installed on the mobile end of the robot 500.

[0035] The clamping jaw assembly 600 includes a main frame 610, the middle part of the top wall of the main frame 610 is connected to the moving end of the robot 500, and the top walls of the left and right parts of the main frame 610 are both installed with cylinders 620, and the piston end of the cylinder 620 is installed with a clamping jaw 630, which passes through the upper and lower parts of the main frame 610. The driving motor 640 is installed on the upper inner wall of the right clamping jaw 630, and the output end of the driving motor 640 passes through the right clamping jaw 630. Pulleys are installed on the output end of the driving motor 640 and the lower right wall of the right clamping jaw 630. A chuck is installed on the left side of the lower pulley, and the chuck is located on the left side of the right clamping jaw 630. A belt 650 is connected between the two sets of pulleys.

[0036] Furthermore, the production line 200 passes through the inner space of the inspection room 100 , and the starting end of the NG line 300 is located in the inner space of the inspection room 100 . The NG line 300 is arranged in parallel with the production line 200 , making it convenient for the robot 500 to place the crankshaft 900 .

[0037] Furthermore, both the left and right parts of the main frame 610 are provided with sliding grooves with upper and lower ends opened, and the clamping claws 630 pass through the sliding grooves of the main frame 610 to facilitate the sliding of the clamping claws 630 so as to clamp the crankshaft 900.

[0038] Furthermore, a pneumatic stopper 001 is provided on the path of the production line 200, and crankshaft supports 700 are evenly placed on both the production line 200 and the NG line 300, so as to facilitate the assembly line-style clamping or placement of the crankshaft 900.

[0039] Furthermore, a crankshaft 900 is placed on the crankshaft support 700 , with both ends of the crankshaft 900 facing the two sides of the production line 200 or the NG line 300 , so that the CCD camera 800 can capture and shoot the crankshaft 900 from the ends.

[0040] Furthermore, the bottom wall of the robot 500 is mounted on the bottom wall inside the inspection room 100 , and the robot 500 is located on the middle line between the production line 200 and the NG line 300 , so as to facilitate the clamping or placement of the crankshaft 900 .

[0041] Furthermore, CCD cameras 800 are installed on both sides of the production line 200 within the range of motion of the robot 500. The CCD cameras 800 are symmetrically arranged to facilitate the CCD cameras 800 to capture images of the crankshaft 900 from the ends.

[0042] Furthermore, the robot 500 is located directly in front of the inspection port of the CCD inspection group 400 , so that the inspection port of the CCD inspection group 400 can inspect the crankshaft 900 from the front.

[0043] A specific application of this embodiment is: in the present invention, the crankshaft 900 product flows onto the production line 200 to be inspected on the crankshaft support 700. After the crankshaft support 700 passes through the clamping and positioning area of the robot 500, the pneumatic stopper 001 accurately positions the crankshaft support 700.

[0044] The sensor on pneumatic stopper 001 sends a detection signal to the CCDs detecting both ends of crankshaft 900. The CCDs have two functions: first, detecting defects on both ends of the crankshaft 900 and second, determining the axial angle to facilitate adjustment of the chuck on the rotating gripper 630 by the robot 500. After the CCDs collect the axial angle θ and the X-axis offset ΔX, they communicate this to the robot 500. The robot 500 then rotates the chuck on the rotating gripper 630 by the aforementioned angle θ into position and then moves to the gripping position based on the ΔX correction amount, thereby gripping the crankshaft 900.

[0045] The robot 500 grabs the crankshaft 900 through the gripper assembly 600. Under the high-speed camera at the detection port of the CCD detection group 400, for each main journal, the distance between the lens and the photographed surface is constant during the rotation of the crankshaft 900. For the four connecting rod journals on both sides, the distance between the lens and the photographed surface is constantly changing during the shooting process. This requires the robot 500 to cooperate with the camera to achieve a constant working distance, and adjust the photo acquisition image according to the forward and backward movement of the crankshaft in the focal plane. Each product has three axis detection positions, a total of 10 cams, and each cam takes a circle. The number of cams distributed on the axis from left to right is 2, 6, and 2 arrays. Each product is photographed ten times. Each movement of the robot 500 sends a shooting signal to the CCD camera. The camera receives the shooting signal of the robot and performs rapid defect analysis on each sub-image of the current product. When defect features appear, the features are recorded and the results are sent to the PLC system while recording this position.

[0046] After the robot obtains the inspection conclusion, it puts the crankshaft back to the original production line or the NG line.

[0047] The principles of gripping and rotating the jaw assembly 600 are as follows: 1. Grasping: the two groups of cylinders 620 contract synchronously, so that the two groups of jaws 630 are close to each other. The bottom inner walls of the two groups of jaws 630 are provided with rotatable clamps. The process of the two groups of jaws 630 approaching each other makes the two groups of clamps clamp the two ends of the crankshaft 900, thus completing the gripping operation; 2. Rotation: the drive motor 640 drives the pulley installed on its output end to rotate, and the pulley drives the pulley connected to the clamp to rotate through the belt 650, thereby rotating the clamp, thereby driving the crankshaft 900 to rotate.

[0048] Through the above-mentioned use of the present invention, the role of the robot 500 in the system, the coordination of movements such as movement and flipping during the grasping and testing process, and the classification after the test are completed, etc., are completed in an integrated manner without the need for intermediate tooling transfers, saving time; each axis is continuously photographed, and the rotating tooling rotates to achieve one axis rotation per one time, which improves efficiency and image stability. It can complete the inspection of a product in 50 seconds; each product is corrected for horizontal position and axial angle before grasping, so that the consistency of the photographed product is high, and each axis is photographed 15 times a week, reducing the impact of arc surface factors on the image. The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above-mentioned embodiment. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention should be equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A machine vision detection method for engine crankshaft journal defects, characterized by: The crankshaft (900) product flows onto the production line (200) to be inspected on the crankshaft support (700). After the crankshaft support (700) passes through the clamping and positioning area of the robot (500), the pneumatic stopper (001) accurately positions the crankshaft support (700); The sensor on the pneumatic stopper (001) sends a detection signal to the CCD of the two end faces of the crankshaft (900) to detect whether there are defects on the two end faces and to locate the axial angle, so that the robot (500) can adjust the chuck on the rotating clamp (630). After the CCD of the crankshaft (900) end face detection completes the acquisition, the axial angle θ and the X-axis offset ΔX are communicated to the robot (500); the chuck on the rotating clamp (630) of the robot (500) rotates to the position according to the above angle θ, and then moves to the grasping position according to the ΔX correction amount, and the crankshaft (900) is grasped; The robot (500) grabs the crankshaft (900) through the gripper assembly (600). Under the high-speed camera of the detection port of the CCD detection group (400), for each main journal, the distance between the lens and the photographed surface is constant during the rotation of the crankshaft (900). For the four connecting rod journals on both sides, the distance between the lens and the photographed surface is constantly changing during the shooting process. The robot (500) cooperates with the camera to achieve a constant working distance. The camera is adjusted according to the forward and backward movement of the crankshaft in the focal plane. Each product has three axis detection positions, a total of 10 cams, and each cam takes a circle. The number of cams distributed on the axis from left to right is 2, 6, and 2 arrays. Each product takes ten pictures. Each time the robot (500) moves, it sends a shooting signal to the CCD camera. The camera receives the shooting signal of the robot and performs a rapid defect analysis on each sub-image of the current product. When a defect feature appears, the feature is recorded and the result is sent to the PLC system while recording the position. After the robot obtains the detection conclusion, it puts the crankshaft back on the original production line or the NG line. The machine vision detection method is implemented by a machine vision detection mechanism for engine crankshaft journal defects, the machine vision detection mechanism comprising a detection room (100), a production line (200), and an NG line (300), and is characterized in that a CCD detection group (400) and a robot (500) are installed inside the detection room (100), and a gripper assembly (600) is installed on the mobile end of the robot (500); The clamping jaw assembly (600) includes a main frame (610), the middle part of the top wall of the main frame (610) is connected to the moving end of the robot (500), the top walls of the left and right parts of the main frame (610) are both installed with cylinders (620), the piston end of the cylinder (620) is installed with a clamping jaw (630), the clamping jaw (630) passes through the upper and lower parts of the main frame (610), the upper inner wall of the right clamping jaw (630) is installed with a driving motor (640), the output end of the driving motor (640) passes through the right clamping jaw (630), the output end of the driving motor (640) and the lower right wall of the right clamping jaw (630) are both installed with pulleys, the left side of the lower pulley is installed with a chuck, and the chuck is located on the left side of the right clamping jaw (630), and a belt (650) is connected between the two groups of pulleys; The production line (200) passes through the inner space of the inspection room (100), the starting end of the NG line (300) is located in the inner space of the inspection room (100), and the NG line (300) is arranged in parallel with the production line (200); The left and right parts of the main frame (610) are both provided with a slide groove with upper and lower ends opened, and the clamping claw (630) passes through the slide groove of the main frame (610); A pneumatic stopper (001) is provided on the path of the production line (200), and crankshaft supports (700) are evenly placed on both the production line (200) and the NG line (300); A crankshaft (900) is placed on the crankshaft support (700), with two ends of the crankshaft (900) facing two sides of the production line (200) or the NG line (300); The bottom wall of the robot (500) is mounted on the bottom wall inside the inspection room (100), and the robot (500) is located on the middle line between the production line (200) and the NG line (300); CCD cameras (800) are installed on both sides of the production line (200) within the range of movement of the robot (500), and the CCD cameras (800) are arranged in a symmetrical shape; The robot (500) is located directly in front of the detection port of the CCD detection group (400).

Images