A device and method for detecting the position of a feature of a part

Abstract

This invention relates to the field of parts inspection technology, specifically to a device and method for detecting the position of non-uniform features on parts. The device includes a camera and a positioning fixture. The camera is positioned directly above the positioning fixture. The positioning fixture includes a flip-up clamping assembly, an auxiliary rotating plate that drives the clamping assembly to flip, and a limiting plate that restricts the flipping position of the auxiliary rotating plate. The clamping assembly clamps the object to be measured. The surface of the clamping assembly is provided with two sets of reference features that respectively match the positioning position and assembly position of the object to be measured. The camera's field of view covers the two sets of reference features. Compared with existing technologies, this invention combines the assembly position and positioning position of two non-uniform surfaces of a part onto a single plane and performs positional relationship measurement on this plane. This enables rapid detection of batch parts on a production line at low cost, facilitates rapid adjustment of assembly equipment, and reduces the alarm rate of assembly equipment.

Description

Technical Field

[0001] This invention relates to the field of parts inspection technology, specifically to a device and method for detecting the location of non-planar features of parts. Background Technology

[0002] During the product manufacturing and assembly process, the parts must first be positioned to confirm the positioning surfaces; then, the assembly surfaces of the two parts are assembled.

[0003] If the locating surface and the assembly surface are on the same plane, then the locating and assembly positions can meet the assembly requirements. However, in many cases, the locating surface and the assembly surface of a part cannot be on the same plane. For example, the locating surface of a part may be located on the front surface of the part, while the assembly surface may be located on the rear surface of the part, and there may be an angle between the assembly position on the assembly surface and the assembly position on the locating surface. Due to differences in raw materials and assembly processes, the size of this angle will fluctuate, and this fluctuation directly affects the alignment during the assembly process, thus affecting the first-pass yield of the assembled products. When the size of this angle exceeds a certain value, assembly misalignment may even trigger equipment alarms, affecting production line operations.

[0004] To solve assembly problems, it is necessary to measure the relationship between the positioning position and the assembly position, such as the included angle, before assembly to confirm whether the spatial positional relationship between the positioning position and the assembly position on two opposite sides of the part meets the assembly requirements.

[0005] Currently, conventional testing methods, such as coordinate measuring machines (CMMs), have drawbacks such as being unable to perform batch testing, being unusable on production lines, and having high testing costs.

[0006] Therefore, it is necessary to design a detection device and method for the location of features on opposite sides of a part, which can quickly detect the positional relationship between assembly positions and positioning positions on two opposite sides of a part in batches. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a device and method for detecting the position of features on opposite sides of a part, which can quickly detect the positional relationship between assembly positions and positioning positions on two opposite sides of a part in batches.

[0008] To achieve the above objectives, the present invention provides a detection device for the position of non-planar features of a part, comprising a camera and a positioning fixture. The camera is located directly above the positioning fixture. The positioning fixture includes a rotatable clamping assembly, an auxiliary rotating plate that drives the clamping assembly to rotate, and a limiting plate that restricts the rotation position of the auxiliary rotating plate. The clamping assembly clamps the object to be measured. The surface of the clamping assembly is provided with two sets of reference features that respectively match the positioning position and assembly position of the object to be measured. The field of view of the camera covers the two sets of reference features.

[0009] The positioning fixture also includes a fixture base and a clamping device. The two ends of the clamping assembly are axially rotatably mounted on the inner side of the fixture base. The middle part of the clamping assembly is fixed to the auxiliary rotating plate. A limit plate is installed on the fixture base below the auxiliary rotating plate. A clamping device is installed on the outer side of the fixture base. The movable end of the clamping device passes through the fixture base and abuts against one end of the clamping assembly.

[0010] A vertical limiting block is provided between the auxiliary rotating plate and the bottom plate of the tooling base.

[0011] The clamping assembly includes a first rotary clamping shaft and a second rotary clamping shaft. The first rotary clamping shaft and the second rotary clamping shaft are respectively installed on the inner ends of the tooling base. The surfaces of the first rotary clamping shaft and the second rotary clamping shaft are provided with a set of reference features, and another set of reference features is provided between the first rotary clamping shaft and the second rotary clamping shaft.

[0012] The clamping device includes clamping plates and clamping screws. Two clamping plates are set on both sides of the tooling base. One clamping plate is provided with a threaded hole. The clamping screw is threadedly connected to the threaded hole. After the end of the clamping screw passes through the tooling base, it abuts against the clamping assembly.

[0013] The two sets of reference features include left and right positioning slots and upper and lower positioning slots that penetrate the clamping assembly. The left and right positioning slots extend outward from the assembly position of the object to be measured, and the upper and lower positioning slots extend outward from the positioning position of the object to be measured.

[0014] A detection method for a device for detecting the position of opposite-sided features of a part includes the following steps: Step 1, after the clamping assembly clamps the object to be measured, the auxiliary rotating plate is rotated to press the auxiliary rotating plate against the limiting plate, the vertical limiting block is removed, and the camera takes pictures of two sets of reference features on the front side of the clamping assembly. The included angle α between the lines connecting the two sets of front reference features is calculated based on the photo parameter information; Step 2, the auxiliary rotating plate is flipped, and the clamping assembly is rotated 180 degrees along the axis. During the flipping process, the clamping assembly keeps the position of the object to be measured unchanged. After the auxiliary rotating plate is pressed against the limiting plate on the other side, the camera takes pictures of the reference features on the back side of the clamping assembly and the assembly position of the object to be measured. The included angle β between the line connecting the reference features on the back side and the line connecting the assembly position of the object to be measured is calculated based on the photo parameter information; Step 3, the included angle γ = α - β between the front and back references is calculated.

[0015] The calculation of the included angle α between the two sets of front reference feature lines based on the photo parameter information includes the following steps: Step 1a, the camera identifies the two center points of the left and right positioning slots on the front of the clamping component, with coordinates of (X1, Y1) and (X2, Y2) respectively, and the coordinates of the line L1 connecting the two center points are [(X1, Y1), (X2, Y2)]; Step 2a, the camera identifies the two center points of the upper and lower positioning slots on the front of the clamping component, with coordinates of (X3, Y3) and (X4, Y4) respectively, and the coordinates of the line L2 connecting the two center points are [(X3, Y3), (X4, Y4)]; Step 3a, the camera software automatically calculates the included angle α between the line L1 [(X1, Y1), (X2, Y2)] and the line L2 [(X3, Y3), (X4, Y4)].

[0016] The calculation of the angle β between the line connecting the reverse reference features and the line connecting the assembly position of the object to be measured, based on the photo parameter information, includes the following steps: Step 1b, the camera identifies the two center points of the left and right positioning slots on the reverse side of the clamping assembly, with coordinates of (X1, Y1) and (X2, Y2) respectively, and the coordinates of the line L1 connecting the two center points are [(X1, Y1), (X2, Y2)]; Step 2b, the camera identifies the center points of the two assembly positions of the object to be measured, with coordinates of (X5, Y5) and (X6, Y6) respectively, and the coordinates of the line L3 connecting the two center points are [(X5, Y5), (X6, Y6)]; Step 3b, the camera software automatically calculates the angle β between the line L1 [(X1, Y1), (X2, Y2)] and the line L3 [(X5, Y5), (X6, Y6)].

[0017] After step 3, step 4 is also included, which determines whether the included angle γ between the front reference and the back reference exceeds the set range. If it does not exceed the set range, the camera sends an OK signal to the PLC, and the PLC controls the assembly equipment to operate normally; if it exceeds the set range, the camera alarms and sends an NG signal to the PLC, and the PLC controls the assembly equipment to scrap the object to be measured.

[0018] Compared with the prior art, this invention combines the assembly positions and positioning positions of two opposite sides of a part onto a single plane and performs positional relationship measurements on that plane. This enables rapid detection of batch parts on the production line in a low-cost manner, facilitates quick adjustment of assembly equipment, and reduces the alarm rate of assembly equipment. Attached Figure Description

[0019] Figure 1 This is a front view of the part non-planar feature position detection device of the present invention.

[0020] Figure 2 This is an isometric view of the positioning fixture of the present invention.

[0021] Figure 3 This is a cross-sectional view of the positioning fixture for removing the clamping screw according to the present invention.

[0022] Figure 4 This is a schematic diagram of the camera acquiring the front reference parameters of the positioning fixture according to the present invention.

[0023] Figure 5 This is a schematic diagram illustrating the camera acquisition of the reverse reference of the positioning fixture and the assembly position parameters of the object to be measured.

[0024] See Figures 1-5 1 is the camera; 2 is the field of view; 3 is the object to be measured; 4 is the auxiliary rotating plate; 5 is the clamping device; 6 is the tooling base; 7 is the limiting plate; 8 is the vertical limiting block; 9 is the clamping assembly; 31 is the assembly position; 51 is the clamping plate; 52 is the clamping screw; 53 is the threaded hole; 91 is the first rotating clamping shaft; 92 is the second rotating clamping shaft; 93 is the left and right positioning groove; 94 is the upper and lower positioning groove. Implementation

[0025] The present invention will now be further described with reference to the accompanying drawings.

[0026] See Figure 1 , Figure 2 and Figure 3 This invention is a detection device for the position of non-planar features of a part, including a camera and a positioning fixture. The camera 1 is located directly above the positioning fixture. The positioning fixture includes a flip-up clamping assembly 9, an auxiliary rotating plate 4 that drives the clamping assembly 9 to flip, and a limiting plate 7 that restricts the flipping position of the auxiliary rotating plate 4. The clamping assembly 9 clamps the object to be measured 3. The surface of the clamping assembly 9 is provided with two sets of reference features that match the positioning position and assembly position of the object to be measured 3, respectively. The field of view 2 of the camera 1 covers the two sets of reference features.

[0027] The object to be measured 3 mentioned in this invention can be any part whose assembly position or positioning position is located on different planes, such as the motor used in the fuel tank leak diagnosis module.

[0028] See Figure 2 , Figure 3 The positioning fixture also includes a fixture base 6 and a clamping device 5. The two ends of the clamping assembly 9 are axially rotatably mounted on the inner side of the fixture base 6. The middle part of the clamping assembly 9 is fixed to the auxiliary rotating plate 4. A limit plate 7 is installed on the fixture base 6 below the auxiliary rotating plate 4. The clamping device 5 is installed on the outer side of the fixture base 6. The movable end of the clamping device 5 passes through the fixture base 6 and abuts against one end of the clamping assembly 9.

[0029] A vertical limiting block 8 is provided between the auxiliary rotating plate 4 and the base plate of the tooling base 6. When the clamping assembly 9 clamps the object to be measured 3, the vertical limiting block 8 limits the object to be measured 3 in the height direction; before the clamping assembly 9 rotates, the vertical limiting block 8 needs to be removed. Since the object to be measured 3 is installed in place, when the clamping assembly 9 rotates, it can ensure that the front and back positions of the object to be measured 3 are at the same level.

[0030] See Figure 2 , Figure 3 The clamping assembly 9 includes a first rotating clamping shaft 91 and a second rotating clamping shaft 92. The first rotating clamping shaft 91 and the second rotating clamping shaft 92 are respectively installed on the inner ends of the tooling base 6. A set of reference features are provided on the surface of the first rotating clamping shaft 91 and the second rotating clamping shaft 92, and another set of reference features are provided between the first rotating clamping shaft 91 and the second rotating clamping shaft 92.

[0031] See Figure 2 , Figure 3 The clamping device 5 includes a clamping plate 51 and a clamping screw 52. The two clamping plates 51 are arranged on both sides of the fixture base 6. One clamping plate 51 is provided with a threaded hole 53. The clamping screw 52 is threadedly connected to the threaded hole 53. After the end of the clamping screw 52 passes through the fixture base 6, it abuts against the clamping assembly 9, so that the clamping assembly 9 always clamps the object to be measured 3, preventing the horizontal position of the object to be measured 3 from changing during the measurement flipping process.

[0032] The two sets of reference features include left and right positioning grooves 93 and upper and lower positioning grooves 94 that pass through the clamping assembly 9. The left and right positioning grooves 93 extend outward from the assembly position of the object to be measured 3, and the upper and lower positioning grooves 94 extend outward from the positioning position of the object to be measured 3.

[0033] This invention combines the assembly and positioning positions of two opposite sides of a part onto a single plane and measures their positional relationships on that plane. This enables rapid detection of batches of parts on the production line in a low-cost manner, facilitates quick adjustment of assembly equipment, and reduces the alarm rate of the assembly equipment. Example

[0034] The method for detecting the position of non-planar features of a part includes the following steps: Step 1, after the clamping assembly 9 clamps the object to be measured 3, the auxiliary rotating plate 4 is rotated to press the auxiliary rotating plate 4 against the limiting plate 7, the vertical limiting block 8 is removed, and the camera 1 takes pictures of the two sets of reference features on the front of the clamping assembly 9. The included angle α between the lines connecting the two sets of frontal reference features is calculated based on the photo parameter information.

[0035] See Figure 4The calculation of the included angle α between the two sets of front reference feature lines based on the photo parameter information includes the following steps: Step 1a, the camera 1 identifies the two center points of the left and right positioning slots 93 on the front of the clamping component 9, with coordinates of (X1, Y1) and (X2, Y2) respectively, and the coordinates of the line L1 connecting the two center points are [(X1, Y1), (X2, Y2)]; Step 2a, the camera 1 identifies the two center points of the upper and lower positioning slots 94 on the front of the clamping component 9, with coordinates of (X3, Y3) and (X4, Y4) respectively, and the coordinates of the line L2 connecting the two center points are [(X3, Y3), (X4, Y4)]; Step 3a, the software of the camera 1 automatically calculates the included angle α between the line L1 [(X1, Y1), (X2, Y2)] and the line L2 [(X3, Y3), (X4, Y4)].

[0036] Step 2: Flip the auxiliary rotating plate 4 and rotate the clamping assembly 9 180 degrees along the axis. During the flipping process, the clamping assembly 9 keeps the position of the object to be measured 3 unchanged. After the auxiliary rotating plate 4 is pressed against the limiting plate 7 on the other side, the camera 1 takes pictures of the reverse reference feature of the clamping assembly 9 and the assembly position of the object to be measured 3. The angle β between the line connecting the reverse reference feature and the line connecting the assembly position of the object to be measured 3 is calculated based on the photo parameter information.

[0037] See Figure 5 The calculation of the angle β between the line connecting the reference features on the reverse side and the line connecting the assembly positions of the object to be measured 3, based on the photo parameter information, includes the following steps: Step 1b, the camera 1 identifies the two center points of the left and right positioning slots 93 on the reverse side of the clamping assembly 9, with coordinates of (X1, Y1) and (X2, Y2) respectively, and the coordinates of the line L1 connecting the two center points are [(X1, Y1), (X2, Y2)]; Step 2b, the camera 1 identifies the center points of the two assembly positions 31 of the object to be measured 3, with coordinates of (X5, Y5) and (X6, Y6) respectively, and the coordinates of the line L3 connecting the two center points are [(X5, Y5), (X6, Y6)]; Step 3b, the software of the camera 1 automatically calculates the angle β between the line L1 [(X1, Y1), (X2, Y2)] and the line L3 [(X5, Y5), (X6, Y6)]. Figure 5 As shown, the line L1[(X1,Y1),(X2,Y2)] coincides with the line L3[(X5,Y5),(X6,Y6)], that is, the angle β between the line L1[(X1,Y1),(X2,Y2)] and the line L3[(X5,Y5),(X6,Y6)] is 0°.

[0038] Step 3: Calculate the angle γ = α - β between the front datum and the back datum. γ is the angle between the positioning position and the assembly position of the object to be measured 3.

[0039] Step 4: Determine whether the included angle γ between the front reference and the back reference exceeds the set range. If it does not exceed the set range, the camera sends an OK signal to the PLC, and the PLC controls the assembly equipment to operate normally. If it exceeds the set range, the camera alarms and sends an NG signal to the PLC, and the PLC controls the assembly equipment to scrap the object to be measured 3.

[0040] In this embodiment, line L1 is used as a reference, and the angle of the object's non-planar features is accurately measured with the help of a camera. This embodiment automates the feeding, clamping, rotation, and camera triggering of the object to be measured, and can be applied to automated production lines.

Claims

1. A device for detecting the position of non-planar features of a part, comprising a camera and a positioning fixture, characterized in that: The camera (1) is located directly above the positioning fixture, which includes a flip-up clamping assembly (9), an auxiliary rotating plate (4) that drives the clamping assembly (9) to flip, and a limiting plate (7) that limits the flipping position of the auxiliary rotating plate (4). The clamping assembly (9) clamps the object to be measured (3). The surface of the clamping assembly (9) is provided with two sets of reference features that match the positioning position and assembly position of the object to be measured (3) respectively. The field of view (2) of the camera (1) covers the two sets of reference features, and the assembly position and positioning position located on two opposite sides of the part are displayed on a plane, and the positional relationship is measured on this plane.

2. The detection device for the location of non-planar features of a part according to claim 1, characterized in that: The positioning fixture also includes a fixture base (6) and a clamping device (5). The two ends of the clamping assembly (9) are axially rotatably mounted on the inner side of the fixture base (6). The middle part of the clamping assembly (9) is fixed to the auxiliary rotating plate (4). A limit plate (7) is installed on the fixture base (6) below the auxiliary rotating plate (4). The clamping device (5) is installed on the outer side of the fixture base (6). The movable end of the clamping device (5) passes through the fixture base (6) and abuts against one end of the clamping assembly (9).

3. The detection device for the location of non-planar features of a part according to claim 2, characterized in that: A vertical limiting block (8) is provided between the auxiliary rotating plate (4) and the bottom plate of the tooling base (6).

4. The detection device for the location of non-planar features of a part according to claim 2, characterized in that: The clamping assembly (9) includes a first rotating clamping shaft (91) and a second rotating clamping shaft (92). The first rotating clamping shaft (91) and the second rotating clamping shaft (92) are respectively installed on the inner ends of the tooling base (6). A set of reference features are provided on the surfaces of the first rotating clamping shaft (91) and the second rotating clamping shaft (92). Another set of reference features is provided between the first rotating clamping shaft (91) and the second rotating clamping shaft (92).

5. The detection device for the location of non-planar features of a part according to claim 2, characterized in that: The clamping device (5) includes a clamping plate (51) and a clamping screw (52). The two clamping plates (51) are set on both sides of the tooling base (6). One clamping plate (51) is provided with a threaded hole (53). The clamping screw (52) is threadedly connected to the threaded hole (53). After the end of the clamping screw (52) passes through the tooling base (6), it abuts against the clamping assembly (9).

6. The detection device for the location of non-planar features of a part according to claim 1, characterized in that: The two sets of reference features include left and right positioning grooves (93) and upper and lower positioning grooves (94) that penetrate the clamping assembly (9). The left and right positioning grooves (93) extend outward from the assembly position of the object to be measured (3), and the upper and lower positioning grooves (94) extend outward from the positioning position of the object to be measured (3).

7. A detection method for a detection device for detecting the location of non-planar features of a part as described in any one of claims 1 to 6, characterized in that: The process includes the following steps: Step 1, after the clamping assembly (9) clamps the object to be measured (3), rotate the auxiliary rotating plate (4) to press the auxiliary rotating plate (4) against the limiting plate (7), remove the vertical limiting block (8), and the camera (1) takes pictures of the two sets of reference features on the front of the clamping assembly (9). Calculate the angle α between the lines connecting the two sets of front reference features based on the photo parameter information; Step 2, flip the auxiliary rotating plate (4) and rotate the clamping assembly (9) 180 degrees along the axis. During the flipping process, the clamping assembly (9) keeps the position of the object to be measured (3) unchanged. After the auxiliary rotating plate (4) is pressed against the limiting plate (7) on the other side, the camera (1) takes pictures of the reverse reference features of the clamping assembly (9) and the assembly position of the object to be measured (3). Calculate the angle β between the line connecting the reverse reference features and the line connecting the assembly position of the object to be measured (3) based on the photo parameter information; Step 3, calculate the angle γ = α - β between the front and reverse references.

8. The detection method of the detection device for detecting the location of non-planar features of a part according to claim 7, characterized in that: The calculation of the included angle α between the two sets of front reference feature lines based on the photo parameter information includes the following steps: Step 1a, the camera (1) identifies the two center points of the left and right positioning slots (93) on the front of the clamping component (9), the coordinates of the two center points are (X1, Y1) and (X2, Y2) respectively, and the coordinates of the line L1 connecting the two center points are [(X1, Y1), (X2, Y2)]; Step 2a, the camera (1) identifies the two center points of the upper and lower positioning slots (94) on the front of the clamping component (9), the coordinates of the two center points are (X3, Y3) and (X4, Y4) respectively, and the coordinates of the line L2 connecting the two center points are [(X3, Y3), (X4, Y4)]; Step 3a, the software of the camera (1) automatically calculates the included angle α between the line L1 [(X1, Y1), (X2, Y2)] and the line L2 [(X3, Y3), (X4, Y4)].

9. The detection method of the detection device for detecting the location of non-planar features of a part according to claim 7, characterized in that: The calculation of the angle β between the line connecting the reverse reference features and the line connecting the assembly position of the object to be measured (3) based on the photo parameter information includes the following steps: Step 1b, the camera (1) identifies the two center points of the left and right positioning slots (93) on the reverse side of the clamping assembly (9), the coordinates of the two center points are (X1, Y1) and (X2, Y2) respectively, and the coordinates of the line L1 connecting the two center points are [(X1, Y1), (X2, Y2)]; Step 2b, the camera (1) identifies the center points of the two assembly positions (31) of the object to be measured (3), the coordinates of the two center points are (X5, Y5) and (X6, Y6) respectively, and the coordinates of the line L3 connecting the two center points are [(X5, Y5), (X6, Y6)]; Step 3b, the software of the camera (1) automatically calculates the angle β between the line L1 [(X1, Y1), (X2, Y2)] and the line L3 [(X5, Y5), (X6, Y6)].

10. The detection method of the detection device for detecting the location of non-planar features of a part according to claim 7, characterized in that: After step 3, step 4 is also included, which determines whether the included angle γ between the front reference and the back reference exceeds the set range. If it does not exceed the set range, the camera sends an OK signal to the PLC, and the PLC controls the assembly equipment to run normally. If it exceeds the set range, the camera alarms and sends an NG signal to the PLC, and the PLC controls the assembly equipment to scrap the object to be measured (3).

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