Flexible combining and splicing system and method for body-in-white main welding line

Abstract

The invention belongs to the technical field of vehicle manufacturing, and discloses a flexible combining and splicing system and method.The flexible combining and splicing system comprises a total splicing frame, an adjustable positioning mechanism assembly, a front windshield frame gripper, a rear wall frame gripper, two side wall frame grippers and two lower vehicle body clamps, and the adjustable positioning mechanism assembly is arranged on the total splicing frame; the front windshield frame grippers, the rear wall frame grippers, the side wall frame grippers and the lower vehicle body clamps are all of adjustable structures and can be rapidly and fixedly connected with the adjustable positioning mechanism assemblies, and the two lower vehicle body clamps are fixed to the ground in the general splicing frame in parallel at intervals. The adjustable gripper serves as a sub-assembly positioning unit, the general splicing frame and the adjustable positioning mechanism assembly serve as a vehicle body positioning mechanism, the gripper drives the sub-assembly to be positioned on the general splicing frame to achieve splicing positioning, the positioning position is adjusted according to the vehicle type, and high-flexibility splicing is achieved; the sub-assembly is photographed and recognized through a visual guidance camera, the grabbing and positioning precision is improved, and the assembly mistake proofing performance is high.

Description

Technical Field

[0001] This invention belongs to the field of automotive manufacturing technology, specifically relating to a flexible assembly system and method for the main welding line of a body-in-white. Background Technology

[0002] To meet the ever-growing product demands of consumers, automakers are increasingly focusing on diversifying their product range. Unlike passenger vehicles, commercial vehicles, as means of production, require even greater product diversification and have a more urgent need for diverse vehicle models. Under the dual pressures of market competition and consumer demand, the process planning of welding production lines is gradually shifting towards higher flexibility and automation to meet ever-changing market needs. The body-in-white assembly station on the main welding line, as the core station of the welding line, is a crucial station for forming the overall body structure and plays a vital role in body-in-white production. In the planning process of a factory (production base) welding workshop, to reduce investment costs, different platform bodyworks often share the main welding line and main assembly station, which places higher demands on the flexibility of the main assembly station. Summary of the Invention

[0003] The purpose of this invention is to provide a flexible assembly system and method for the main welding line of a body-in-white. An adjustable gripper serves as a sub-assembly positioning unit, while the main assembly frame and adjustable positioning mechanism components act as the body positioning mechanism. The gripper positions the sub-assemblies on the main assembly frame to achieve assembly positioning. The controller reads vehicle model information via RFID and controls the adjustable positioning mechanism components and gripper to switch to corresponding fixed positions, resulting in high flexibility. A vision-guided camera photographs and identifies the sub-assemblies, improving gripping and positioning accuracy and providing high error prevention during assembly.

[0004] The specific details of the plan are as follows:

[0005] A flexible assembly system for a body-in-white main welding line includes a main assembly frame, an adjustable positioning mechanism assembly, a rear frame gripper, a front windshield frame gripper, two side frame grippers, and a lower body clamp. The main assembly frame is fixedly supported on the ground. The adjustable positioning mechanism assembly is respectively set on the main assembly frame according to the assembly position of the sub-assemblies, and is used for quick and detachable fixed connection of the rear frame gripper, the front windshield frame gripper, and the two side frame grippers. The connection position of the grippers can be adjusted according to the vehicle model. The rear frame gripper, the front windshield frame gripper, the two side frame grippers, and the two lower body clamps are all adjustable structures, used for fixing the front windshield assembly, the rear assembly, the two side assemblies, and the lower body assembly, and the fixing and clamping position of the sub-assemblies can be adjusted according to the vehicle model. The two lower body clamps are symmetrically spaced on the ground within the main assembly frame.

[0006] The flexible assembly system of the main welding line for the body-in-white of this invention includes a general assembly frame comprising four columns and an adjustable positioning mechanism assembly comprising a front windshield positioning mechanism, a rear panel positioning mechanism, and two side panel positioning mechanisms (i.e., left and right side panel positioning mechanisms). The adjustable positioning mechanism assembly and the general assembly frame together serve as the body size positioning mechanism. The front windshield positioning mechanism, rear panel positioning mechanism, and two side panel positioning mechanisms have similar structures and operate on the same principle; however, their detailed shapes and dimensions may vary slightly depending on the different sub-assemblies they grip and clamp. The X-direction of a car is longitudinal (front-to-back), the Y-direction is lateral (left-to-right), and the Z-direction is vertical (up-down). The front windshield positioning mechanism and the rear panel positioning mechanism have identical structures and are used for positioning adjustment in the X-direction of the car. The two side panel positioning mechanisms, namely the left and right side panel positioning mechanisms, have identical structures and are used for positioning adjustment in the Y-direction of the car. The front windshield positioning mechanism, rear panel positioning mechanism, and two side panel positioning mechanisms all need to be used in pairs. They are symmetrically arranged on the frame columns for detachable and fixed connection of the front windshield frame gripper, rear panel frame gripper, and the two side panel frame grippers. The adjustable positioning mechanisms are installed in the order that the front windshield, rear panel assembly, and two side panel assemblies surround the assembled unit. Two lower body clamps are symmetrically spaced on the ground within the assembly frame. The bottom of the main line skid's rail is fixed between the two lower body clamps. The main line skid transports the lower body assembly or assembled sub-assemblies according to controller commands. The four assembly robots are equipped with gripper tools and welding pliers tools; switching tools allows for the loading of the corresponding gripper or welding pliers. Before assembly, the assembly robot typically switches gripper tools and loads the corresponding grippers. When it receives a controller command to perform assembly, each gripper adjusts its positioning according to the vehicle model information. The assembly robot carries the corresponding gripper to the sub-assembly loading station to pick up the correct vehicle model sub-assembly. It then uses vision-guided cameras on each gripper to take pictures and compares them with pre-recorded vehicle model sub-assemblies. If an error occurs, it sends information to the controller, and the error alarm device alerts the robot to re-pick the correct sub-assembly. If the comparison result is correct, the robot adjusts the position of the sub-assembly based on the pre-recorded information, improving the gripping and positioning accuracy and ensuring high error prevention during assembly.

[0007] The rear frame gripper and the two side frame grippers each include a cylinder-driven sliding mechanism and a flipping mechanism for positioning and adjusting the rear frame gripper and the two side frames. The front windshield frame gripper includes a flipping mechanism for positioning and adjusting the front windshield frame gripper. The adjustable positioning mechanism assembly is positioned and adjusted by a cylinder-driven sliding mechanism. The adjustable positioning mechanism assembly, the front windshield frame gripper, the rear frame gripper, and the two side frame grippers together achieve the flexible assembly of the main welding line of the body-in-white of the present invention.

[0008] Furthermore, the overall assembly frame includes four frame columns, and the adjustable positioning mechanism components include a front windshield positioning mechanism, a rear wall positioning mechanism, and two side wall positioning mechanisms. The front windshield positioning mechanism, the rear wall positioning mechanism, and the two side wall positioning mechanisms are used in pairs and symmetrically fixed at the corresponding positions on the frame columns, respectively for fixing and connecting the rear wall frame grab, the front windshield frame grab, and the two side wall frame grabs.

[0009] The front windshield positioning mechanism, rear wall positioning mechanism, and two side wall positioning mechanisms are all used in pairs. They are fixed to the corresponding frame columns according to the positions of each sub-assembly after assembly, and are used for detachable and fixed connection of the wall frame grab, the front windshield frame grab, and the two side wall frame grabs.

[0010] Furthermore, the front windshield positioning mechanism and the rear surround positioning mechanism have the same structure, both including a positioning base plate, a positioning sliding mechanism, a gripper frame positioning pin, a gripper frame positioning surface, a gripper frame three-way limiting block, an X-axis pressing unit, and an X-axis and Z-axis bidirectional pressing unit. The positioning base plate is fixed on the corresponding frame column. The positioning sliding mechanism, gripper frame positioning pin, gripper frame positioning surface, gripper frame three-way limiting block, X-axis pressing unit, and X-axis and Z-axis bidirectional pressing unit are all disposed on the positioning base plate. The positioning sliding mechanism includes a cylinder drive mechanism. The positioning sliding mechanism slides under the drive of the cylinder for positioning adjustment of the front windshield positioning mechanism / rear surround positioning mechanism in the X-axis. The gripper frame positioning pin is used for positioning connection with the corresponding gripper.

[0011] Furthermore, the side wall positioning mechanism and the front windshield positioning mechanism have the same structure, including a positioning base plate, a positioning sliding mechanism, a gripper frame positioning pin, a gripper frame positioning surface, a gripper frame three-way limiting block, a Y-axis pressing unit, and a Y-axis and Z-axis bidirectional pressing unit. The Y-axis pressing unit has the same structure as the X-axis pressing unit of the front windshield positioning mechanism, and the Y-axis and Z-axis bidirectional pressing unit has the same structure as the X-axis and Z-axis bidirectional pressing unit of the front windshield positioning mechanism. It is used for positioning adjustment of the side wall positioning mechanism in the Y direction.

[0012] The side panel positioning mechanism has the same structure as the windshield positioning mechanism. The Y-axis pressing unit has the same structure as the X-axis pressing unit of the windshield positioning mechanism. The Y-axis and Z-axis bidirectional pressing unit has the same structure as the X-axis and Z-axis bidirectional pressing unit of the windshield positioning mechanism; they differ only in orientation, pressing direction, and adjustment direction, hence the different names. The positioning base plate, positioning sliding mechanism, gripper frame positioning pin, gripper frame positioning surface, and gripper frame three-way limiting block have the same structure. The adjustment and positioning principles of the windshield positioning mechanism, rear panel positioning mechanism, and two side panel positioning mechanisms are the same; however, the dimensions are adjusted according to different vehicle models in practical applications.

[0013] Furthermore, the rear frame gripper includes a rear gripper frame, an X-axis positioning block, a gripper sliding mechanism, a frame gripper main positioning unit, a frame gripper three-axis positioning unit, a wide vehicle Z-axis upward positioning unit, a narrow vehicle Z-axis upward positioning unit, a narrow vehicle Y-axis leftward positioning unit, a wide vehicle Y-axis leftward positioning unit, a narrow vehicle Z-axis downward positioning unit, a wide vehicle Z-axis downward positioning unit, a narrow vehicle Y-axis rightward positioning unit, a wide vehicle Y-axis rightward positioning unit, and a visual guidance camera. The rear frame gripper frame is quickly and detachably fixedly connected to the corresponding adjustable positioning mechanism components. The X-axis positioning block, gripper sliding mechanism, frame gripper main positioning unit, frame gripper three-axis positioning unit, wide vehicle Z-axis upward positioning unit, narrow vehicle Z-axis upward positioning unit, narrow vehicle Y-axis leftward positioning unit, wide vehicle Y-axis leftward positioning unit, narrow vehicle Z-axis downward positioning unit, wide vehicle Z-axis downward positioning unit, narrow vehicle Y-axis rightward positioning unit, wide vehicle Y-axis rightward positioning unit, and visual guidance camera are all located in the rear frame. On the gripper frame, the gripper sliding mechanism includes a cylinder-driven mechanism. Under the drive of the cylinder, the gripper sliding mechanism slides left / right for the Y-axis positioning adjustment of the rear frame gripper. The narrow vehicle Z-axis upward positioning unit, the wide vehicle Y-axis left positioning unit, and the wide vehicle Y-axis right positioning unit all include a flipping mechanism. The narrow vehicle Z-axis upward positioning unit flips up / down for the Z-axis positioning adjustment of the rear frame gripper. The wide vehicle Y-axis left positioning unit and the wide vehicle Y-axis right positioning unit flip inward / outward for the Y-axis positioning adjustment of the rear frame gripper. The wide vehicle Z-axis downward positioning unit includes a cylinder-driven mechanism. Under the drive of the cylinder, the wide vehicle Z-axis downward positioning unit slides along the Z-axis for the Z-axis positioning adjustment of the rear frame gripper. The vision guidance camera is used to take pictures and compare them with the vehicle model information already entered in the system to determine the correctness of the vehicle model and adjust the gripper position. The main positioning unit of the frame gripper is provided with a positioning hole for positioning and connection with the gripper frame positioning pin.

[0014] Furthermore, the windshield frame gripper includes a main positioning unit, a three-way positioning unit, a bidirectional positioning and clamping unit for the windshield in X and Z directions for wide vehicles, a bidirectional positioning and clamping unit for the windshield in X and Z directions for narrow vehicles, a main positioning pin for the windshield, auxiliary positioning pins for the main positioning pins of the windshield in narrow vehicles, auxiliary positioning pins for the main positioning pins of the windshield in wide vehicles, and a windshield gripper frame. The X-axis and Z-axis bidirectional positioning clamping unit, the windshield X-axis and Z-axis bidirectional positioning clamping unit, the windshield main positioning pin, the narrow vehicle windshield main positioning pin and auxiliary positioning pin, and the wide vehicle windshield main positioning pin and auxiliary positioning pin are respectively set on the windshield gripper frame. The wide vehicle windshield X-axis and Z-axis bidirectional positioning clamping unit and the narrow vehicle windshield X-axis and Z-axis bidirectional positioning clamping unit both include a flipping mechanism. The wide vehicle windshield X-axis and Z-axis bidirectional positioning clamping unit and the narrow vehicle windshield X-axis and Z-axis bidirectional positioning clamping unit are flipped accordingly according to different vehicle models for the X-axis positioning adjustment of the windshield.

[0015] The wide vehicle's windshield features a bidirectional X-axis and Z-axis positioning clamping unit for bidirectional positioning and clamping in both directions. The narrow vehicle's windshield features a bidirectional X-axis and Z-axis positioning clamping unit for bidirectional positioning and clamping in both directions. This unit is shared by both wide and narrow vehicles. The main positioning pin for the windshield is shared by both wide and narrow vehicles and connects to the main positioning hole of the windshield assembly. The auxiliary positioning pin for the narrow vehicle's main positioning pin is a dedicated auxiliary positioning pin that connects to the auxiliary positioning hole of the narrow vehicle's windshield. The auxiliary positioning pin for the wide vehicle's main positioning pin is a dedicated auxiliary positioning pin that connects to the auxiliary positioning hole of the wide vehicle's windshield.

[0016] Furthermore, the two side frame grippers have identical structures, including a side main positioning pin, a side front Y-positioning clamping unit, a side X-positioning clamping unit, a side Z-positioning clamping unit, a side length / short carriage switching sliding mechanism, a side auxiliary positioning pin, a side rear Y-positioning clamping unit, a side gripper three-way positioning unit, a side gripper main positioning unit, a side gripper frame, and a vision guidance camera. The short carriage switching sliding mechanism, side auxiliary positioning pin, side rear Y-axis positioning clamping unit, side gripper three-axis positioning unit, side gripper main positioning and visual guidance camera are all set on the side gripper frame. The side carriage switching sliding mechanism includes a cylinder drive mechanism for positioning adjustment of the side gripper in the X-axis. The side front Y-axis positioning clamping unit, side X-axis positioning clamping unit, side Z-axis positioning clamping unit and side rear Y-axis positioning clamping unit all include a flipping mechanism to achieve positioning adjustment of the side frame gripper through flipping.

[0017] The visual guidance camera is used to take pictures and compare them with the vehicle model information already entered in the system to determine whether the vehicle model is correct and adjust the gripping position accordingly.

[0018] Furthermore, each lower body fixture includes a small fixture base plate, a floor front end positioning unit, a narrow vehicle floor rear end positioning unit, and a wide vehicle rear end positioning unit. The floor front end positioning unit, the narrow vehicle floor rear end positioning unit, and the wide vehicle rear end positioning unit are all disposed on the small fixture base plate. The floor front end positioning unit and the wide vehicle rear end positioning unit both include a cylinder drive mechanism. The floor front end positioning unit slides in the Y direction under the drive of the cylinder for Y-direction positioning adjustment of the lower body fixture, and the wide vehicle rear end positioning unit slides in the X direction under the drive of the cylinder for X-direction positioning adjustment of the lower body fixture.

[0019] Furthermore, it also includes four assembly robots, a main line skid, a welding clamp parking station, a sub-assembly loading station, an error alarm device, and a controller. Each assembly robot includes a welding clamp tool and a gripper tool. The welding clamp parking station is used to store welding clamps. The assembly robot can access and retrieve welding clamps from the welding clamp parking station by switching welding clamp tools. The sub-assembly loading station is used to store the front windshield assembly, rear bulkhead assembly, and two side bulkhead assemblies. The assembly robot can load the corresponding gripper by switching gripper tools and retrieve the corresponding sub-assembly through the corresponding gripper. The assembly robots, main line skid, adjustable positioning mechanism components, rear bulkhead frame gripper, front windshield frame gripper, side bulkhead frame gripper, and lower body clamps are all electrically connected to the controller. The controller includes an RFID reader for reading vehicle model information of the lower body assembly. The main line skid is set on the ground between the two lower body clamps. The error alarm device is electrically connected to the controller and is used to issue an alarm when the visual guidance camera detects an error in the gripped part after comparing the photographed information.

[0020] A flexible assembly method for a main welding line of a body-in-white, comprising the steps of applying the aforementioned flexible assembly system for the main welding line of a body-in-white, including:

[0021] S1. After the controller reads the vehicle model information of the lower body assembly transported by the main line skid through the RFID reader, it sends the information to the assembly robot, adjustable positioning mechanism component, front windshield frame gripper, rear frame gripper, side frame gripper and lower body fixture.

[0022] S2. The lower body assembly is transported to the two lower body clamps of the main assembly frame via the main line skid. The lower body clamps adjust their positioning position according to the vehicle information. The main line skid descends and the lower body assembly falls from the main line skid onto the lower body clamps and is clamped and fixed.

[0023] S3. The front windshield frame gripper, rear frame gripper, and two side frame grippers adjust their positioning positions according to the vehicle model information. The four assembly robots switch gripper tools respectively, load the corresponding front windshield frame gripper, rear frame gripper, and two side frame grippers, and move them to the sub-assembly loading station. The front windshield frame gripper, rear frame gripper, and two side frame grippers respectively grab the corresponding front windshield assembly, rear frame assembly, and two side assemblies. During the grabbing process, a vision-guided camera takes pictures and compares them with the recorded vehicle model information to determine whether the grabbed sub-assembly model is correct. If the model is determined to be incorrect, the error alarm device automatically alarms and prompts a re-grabbing. If the model is correct, the gripping position is adjusted according to the recorded model information. After grabbing the corresponding sub-assembly, the assembly robot carries the corresponding sub-assembly to the assembly frame.

[0024] S4. After receiving the controller information, the front windshield positioning mechanism, rear wall positioning mechanism and two side wall positioning mechanisms on the assembly frame adjust their positioning positions according to the vehicle model information. The four assembly robots carry the sub-assemblies to the corresponding adjustable positioning mechanism components. The assembly robots fix the front windshield frame gripper, rear wall frame gripper and two side wall frame grippers to the corresponding front windshield positioning mechanism, rear wall positioning mechanism and two side wall positioning mechanism respectively.

[0025] S5. The assembly robot disengages from the corresponding gripper and switches to the welding gun tool, moves to the welding gun parking station to load the welding gun, returns to the main assembly frame, and performs spot welding on each sub-assembly after assembly. After welding is completed, the assembly robot moves to the welding gun parking station to disengage from the welding gun, switches the gripper tool to reload the corresponding gripper, and waits for the next assembly.

[0026] S6. The lower body clamp releases the lower body assembly, the main line skid rises, and the assembled front windshield assembly, rear bulkhead assembly, left side bulkhead assembly, right side bulkhead assembly and lower body assembly are taken away from the lower body clamp and sent to the next work station.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] This invention uses an adjustable gripper as a sub-assembly positioning unit, and a main assembly frame and an adjustable positioning mechanism as a vehicle body positioning mechanism. The gripper positions the sub-assembly on the main assembly frame to achieve assembly positioning. The controller reads vehicle model information via RFID and controls the adjustable positioning mechanism and gripper to switch to the corresponding fixed positions, achieving high flexibility. A visually guided camera takes pictures of the sub-assemblies for identification, improving the gripping and positioning accuracy and ensuring high error prevention in assembly. Attached Figure Description

[0029] Figure 1 This is a schematic diagram showing the fixed connection of the overall assembly frame, gripper, and adjustable positioning mechanism components of the present invention.

[0030] Figure 2 This is a schematic diagram of the overall assembly framework of the present invention.

[0031] Figure 3 This is a schematic diagram of the front windshield positioning mechanism, rear wall positioning mechanism, and side wall positioning mechanism of the present invention.

[0032] Figure 4 This is a schematic diagram of the structure of the rear frame gripper of the present invention.

[0033] Figure 5 This is a partially enlarged schematic diagram of the rear frame gripper A region of the present invention.

[0034] Figure 6 This is a schematic diagram of the front windshield grabber of the present invention.

[0035] Figure 7 This is a schematic diagram of the side frame gripper of the present invention.

[0036] Figure 8 This is a schematic diagram showing the positional structure of the two undercarriage clamps of the present invention.

[0037] 1. Overall assembly frame; 1.1. Frame pillars; 2. Adjustable positioning mechanism components; 2.1. Front windshield positioning mechanism; 2.11. Positioning base plate; 2.12. Positioning sliding mechanism; 2.13. Handle frame positioning pin; 2.14. Handle frame positioning surface; 2.15. Handle frame three-way limiting block; 2.16. X-axis clamping unit; 2.17. X-axis and Z-axis bidirectional clamping unit; 2.2. Rear enclosure positioning mechanism; 2.3. Side enclosure positioning mechanism; 3. Rear enclosure frame handle; 3.1. Rear enclosure handle Hand frame; 3.2. X-axis positioning block; 3.3. Gripper sliding mechanism; 3.4. Frame gripper main positioning unit; 3.5. Frame gripper three-axis positioning unit; 3.6. Wide carriage Z-axis upward positioning unit; 3.7. Narrow carriage Z-axis upward positioning unit; 3.8. Narrow carriage Y-axis leftward positioning unit; 3.9. Wide carriage Y-axis leftward positioning unit; 3.10. Narrow carriage Z-axis downward positioning unit; 3.11. Wide carriage Z-axis downward positioning unit; 3.12. Narrow carriage Y-axis rightward positioning unit; 3.13. Wide carriage Y-axis rightward positioning unit; 4. Windshield frame gripper; 4.1. Windshield frame gripper main positioning unit; 4.2. Windshield frame gripper three-way positioning unit; 4.3. Wide vehicle windshield X-axis and Z-axis bidirectional positioning and clamping unit; 4.4. Narrow vehicle windshield X-axis and Z-axis bidirectional positioning and clamping unit; 4.5. Windshield X-axis and Z-axis bidirectional positioning and clamping unit; 4.6. Windshield main positioning pin; 4.7. Narrow vehicle windshield main positioning pin and auxiliary positioning pin; 4.8. Wide vehicle windshield main positioning pin and auxiliary positioning pin; 4.9. Windshield gripper frame; 5. Side frame gripper; 5.1. Side main positioning pin; 5.2 5.3. Side panel front Y-axis positioning clamping unit; 5.4. Side panel X-axis positioning clamping unit; 5.5. Side panel long / short vehicle switching sliding mechanism; 5.6. Side panel auxiliary positioning pin; 5.7. Side panel rear Y-axis positioning clamping unit; 5.8. Side panel gripper three-way positioning unit; 5.9. Side panel gripper main positioning; 5.10. Side panel gripper frame; 6. Underbody fixture; 6.1. Fixture small base plate; 6.2. Floor front positioning unit; 6.3. Narrow vehicle floor rear positioning unit; 6.4. Wide vehicle rear positioning unit; 7. Visual guidance camera. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0039] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0040] It should be noted that the terms "front", "rear", "inner", "outer", "left", "right", etc., used in this invention to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] It is particularly important to note that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals. The following section will discuss this further. Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 The present invention will now be described in detail.

[0042] Example 1:

[0043] See Figure 1 (For ease of viewing, one side frame gripper is omitted from the diagram.) As shown, a flexible assembly system for a white body main welding line includes a main assembly frame 1, an adjustable positioning mechanism assembly 2, a rear frame gripper 3, a front windshield frame gripper 4, two side frame grippers 5, and a lower body clamp 6. The main assembly frame 1 is fixedly supported on the ground. The adjustable positioning mechanism assembly 2 is respectively set on the main assembly frame 1 according to the assembly position of the sub-assemblies, and is used for quick and detachable fixed connection of the rear frame gripper 3, the front windshield frame gripper 4, and the two side frame grippers 5. The connection position of the grippers can be adjusted according to the vehicle model. The rear frame gripper 3, the front windshield frame gripper 4, the two side frame grippers 5, and the two lower body clamps 6 are all adjustable structures, used for fixing the front windshield assembly, the rear assembly, the two side assemblies, and the lower body assembly, and the fixing clamping position of the sub-assemblies can be adjusted according to the vehicle model. The two lower body clamps 6 are symmetrically spaced on the ground inside the main assembly frame 1.

[0044] See Figure 2As shown, the overall frame 1 includes four frame columns 1.1, and the adjustable positioning mechanism assembly 2 includes a front windshield positioning mechanism 2.1, a rear wall positioning mechanism 2.2, and two side wall positioning mechanisms 2.3. The front windshield positioning mechanism 2.1, the rear wall positioning mechanism 2.2, and the two side wall positioning mechanisms 2.3 are used in pairs and symmetrically fixed at the corresponding positions of the frame columns 1.1, respectively for fixing and connecting the rear wall frame grabber 3, the front windshield frame grabber 4, and the two side wall frame grabbers 5.

[0045] See Figure 3 As shown, the front windshield positioning mechanism 2.1 and the rear surround positioning mechanism 2.2 have the same structure, both including a positioning base plate 2.11, a positioning sliding mechanism 2.12, a gripper frame positioning pin 2.13, a gripper frame positioning surface 2.14, a gripper frame three-way limiting block 2.15, an X-axis pressing unit 2.16, and an X-axis and Z-axis bidirectional pressing unit 2.17. The positioning base plate 2.11 is fixed to the corresponding frame column 1.1, and the positioning sliding mechanism 2.12 and gripper frame positioning pin 2.13... 3. The gripper frame positioning surface 2.14, the gripper frame three-way limiting block 2.15, the X-axis pressing unit 2.16, and the X-axis and Z-axis bidirectional pressing unit 2.17 are all disposed on the positioning small base plate 2.11. The positioning sliding mechanism 2.12 includes a cylinder driving mechanism. The positioning sliding mechanism 2.12 slides under the drive of the cylinder for the positioning adjustment of the front windshield positioning mechanism 2.1 / rear surround positioning mechanism 2.2 in the X-axis. The gripper frame positioning pin 2.13 is used for positioning connection with the corresponding gripper.

[0046] The side wall positioning mechanism 2.3 and the front windshield positioning mechanism 2.1 have the same structure. The side wall positioning mechanism 2.3 includes a positioning base plate, a positioning sliding mechanism, a gripper frame positioning pin, a gripper frame positioning surface, a gripper frame three-way limiting block, a Y-axis pressing unit and a Y-axis and Z-axis bidirectional pressing unit. The Y-axis pressing unit has the same structure as the X-axis pressing unit 2.16 of the front windshield positioning mechanism 2.1, and the Y-axis and Z-axis bidirectional pressing unit has the same structure as the X-axis and Z-axis bidirectional pressing unit 2.17 of the front windshield positioning mechanism 2.1, and is used for the Y-axis positioning adjustment of the side wall positioning mechanism.

[0047] See Figure 4 and Figure 5As shown, the rear frame gripper 3 includes a rear gripper frame 3.1, an X-axis positioning block 3.2, a gripper sliding mechanism 3.3, a frame gripper main positioning unit 3.4, a frame gripper three-axis positioning unit 3.5, a wide vehicle Z-axis upward positioning unit 3.6, a narrow vehicle Z-axis upward positioning unit 3.7, a narrow vehicle Y-axis leftward positioning unit 3.8, a wide vehicle Y-axis leftward positioning unit 3.9, a narrow vehicle Z-axis downward positioning unit 3.10, a wide vehicle Z-axis downward positioning unit 3.11, a narrow vehicle Y-axis rightward positioning unit 3.12, a wide vehicle Y-axis rightward positioning unit 3.13, and a vision guidance camera. 7. The rear gripper frame 3.1 is quickly and detachably fixedly connected to the corresponding adjustable positioning mechanism component 2, including: X-axis positioning block 3.2, gripper sliding mechanism 3.3, frame gripper main positioning unit 3.4, frame gripper three-way positioning unit 3.5, wide vehicle Z-axis upward positioning unit 3.6, narrow vehicle Z-axis upward positioning unit 3.7, narrow vehicle Y-axis leftward positioning unit 3.8, wide vehicle Y-axis leftward positioning unit 3.9, narrow vehicle Z-axis downward positioning unit 3.10, wide vehicle Z-axis downward positioning unit 3.11, narrow vehicle Y-axis rightward positioning unit 3.12, wide vehicle Y-axis rightward positioning unit. Both the element 3.13 and the visual guidance camera 7 are mounted on the rear gripper frame 3.1. The gripper sliding mechanism 3.3 includes a cylinder drive mechanism. Under the drive of the cylinder, the gripper sliding mechanism 3.3 slides left / right for the Y-axis positioning adjustment of the rear frame gripper 3. The narrow vehicle Z-axis upward positioning unit 3.7, the wide vehicle Y-axis left positioning unit 3.9, and the wide vehicle Y-axis right positioning unit 3.13 all include a flipping mechanism. The narrow vehicle Z-axis upward positioning unit 3.7 flips up / down for the Z-axis positioning adjustment of the rear frame gripper 3.1. The wide vehicle Y-axis left positioning unit 3.9 and the wide vehicle Y-axis right positioning unit 3.13 all include a flipping mechanism. The Y-direction right positioning unit 3.13 flips inward / outward for adjusting the Y-position of the rear frame gripper 3 in the Y direction. The wide vehicle Z-direction downward positioning unit 3.11 includes a cylinder drive mechanism. The wide vehicle Z-direction downward positioning unit 3.11 slides along the Z direction under the cylinder drive for adjusting the Z-position of the rear frame gripper 3 in the Z direction. The visual guidance camera 7 is used to take pictures and compare them with the vehicle model information already entered in the system to determine the correctness of the vehicle model and adjust the gripper position. The frame gripper main positioning unit 3.4 is provided with positioning holes for positioning connection with the gripper frame positioning pin 2.13.

[0048] See Figure 6As shown, the windshield frame gripper 4 includes a main positioning unit 4.1, a three-way positioning unit 4.2, a bidirectional positioning and clamping unit 4.3 for wide vehicles (X and Z directions), a bidirectional positioning and clamping unit 4.4 for narrow vehicles (X and Z directions), a bidirectional positioning and clamping unit 4.5 for the windshield (X and Z directions), a main positioning pin 4.6 for the windshield, a main positioning pin and auxiliary positioning pin 4.7 for narrow vehicles, a main positioning pin and auxiliary positioning pin 4.8 for wide vehicles, and a windshield gripper frame 4.9. The main positioning unit 4.1, the three-way positioning unit 4.2, the bidirectional positioning and clamping unit 4.3 for wide vehicles (X and Z directions), the auxiliary positioning pin 4.8 for wide vehicles, and the main positioning pin and auxiliary positioning pin 4.9 for the windshield frame gripper frame 4.9 are also described. The front windshield X-axis and Z-axis bidirectional positioning clamping unit 4.4, the front windshield X-axis and Z-axis bidirectional positioning clamping unit 4.5, the front windshield main positioning pin 4.6, the narrow vehicle front windshield main positioning pin and auxiliary positioning pin 4.7, and the wide vehicle front windshield main positioning pin and auxiliary positioning pin 4.8 are respectively set on the front windshield grab frame 4.9. The wide vehicle front windshield X-axis and Z-axis bidirectional positioning clamping unit 4.3 and the narrow vehicle front windshield X-axis and Z-axis bidirectional positioning clamping unit 4.4 both include a flipping mechanism. The wide vehicle front windshield X-axis and Z-axis bidirectional positioning clamping unit 4.3 and the narrow vehicle front windshield X-axis and Z-axis bidirectional positioning clamping unit 4.4 are flipped according to different vehicle models for the X-axis positioning adjustment of the front windshield.

[0049] See Figure 7 As shown, the two side frame grippers 5 have the same structure. Each side frame gripper 5 includes a side main positioning pin 5.1, a side front Y-positioning clamping unit 5.2, a side X-positioning clamping unit 5.3, a side Z-positioning clamping unit 5.4, a side long / short carriage switching sliding mechanism 5.5, a side auxiliary positioning pin 5.6, a side rear Y-positioning clamping unit 5.7, a side gripper three-way positioning unit 5.8, a side gripper main positioning unit 5.9, a side gripper frame 5.10, and a vision guidance camera 7. Components 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, and 7 are all mounted on the side gripper frame 5.10. The side gripper length-short carriage switching sliding mechanism 5.5 includes a cylinder drive mechanism for adjusting the positioning of the side gripper in the X direction. The side gripper front Y-positioning clamping unit 5.2, 5.3, 5.4, and 5.7 all include a flipping mechanism to adjust the positioning of the side gripper 5.

[0050] See Figure 8As shown, each lower body fixture 6 includes a fixture base plate 6.1, a floor front end positioning unit 6.2, a narrow vehicle floor rear end positioning unit 6.3, and a wide vehicle rear end positioning unit 6.4. The floor front end positioning unit 6.2, the narrow vehicle floor rear end positioning unit 6.3, and the wide vehicle rear end positioning unit 6.4 are all mounted on the fixture base plate 6.1. Both the floor front end positioning unit 6.2 and the wide vehicle rear end positioning unit 6.4 include a cylinder drive mechanism. The floor front end positioning unit 6.2 slides in the Y direction under cylinder drive for Y-axis positioning adjustment of the lower body fixture 6, and the wide vehicle rear end positioning unit 6.4 slides in the X direction under cylinder drive for X-axis positioning adjustment of the lower body fixture 6.

[0051] It also includes four assembly robots, a main line skid, a welding clamp parking station, a sub-assembly loading station, an error alarm device, and a controller. Each assembly robot includes a welding clamp tool and a gripper tool. The welding clamp parking station is used to store welding clamps. The assembly robot can access and retrieve welding clamps from the welding clamp parking station by switching welding clamp tools. The sub-assembly loading station is used to store the front windshield assembly, the rear bulkhead assembly, and the two side bulkhead assemblies. The assembly robot can load the corresponding gripper by switching gripper tools and retrieve the corresponding sub-assembly through the corresponding gripper. The assembly robots, the main line skid, the adjustable positioning mechanism component 2, the rear bulkhead frame gripper 3, the front windshield frame gripper 4, the side bulkhead frame gripper 5, and the lower body clamp 6 are all electrically connected to the controller. The controller includes an RFID reader for reading the vehicle model information of the lower body assembly. The main line skid is set on the ground between the two lower body clamps 6. The error alarm device is electrically connected to the controller and is used to issue an alarm when the visual guidance camera 7 detects an error in the gripped part after comparing the photographed information.

[0052] Example 2:

[0053] This invention also provides a flexible assembly method for the main welding line of a body-in-white, the method of performing flexible assembly using the aforementioned flexible assembly system for the main welding line of a body-in-white, comprising the following steps:

[0054] S1. After the controller reads the vehicle model information of the lower body assembly transported by the main line skid through the RFID reader, it sends the information to the assembly robot, adjustable positioning mechanism component 2, rear frame gripper 3, front windshield frame gripper 4, side frame gripper 5 and lower body clamp 6.

[0055] S2. The lower body assembly is transported to the two lower body clamps 6 of the main body frame 1 via the main line skid. The lower body clamps 6 adjust their positioning position according to the vehicle information. The main line skid descends and the lower body assembly falls from the main line skid into the lower body clamps 6 and is clamped and fixed.

[0056] S3, rear frame gripper 3, front windshield frame gripper 4, and two side frame grippers 5 adjust their positioning positions according to the vehicle model information. The four assembly robots switch gripper tools respectively to load the corresponding rear frame gripper 3, front windshield frame gripper 4, and two side frame grippers 5 and move them to the sub-assembly loading station. The rear frame gripper 3, front windshield frame gripper 4, and two side frame grippers 5 respectively grab the corresponding front windshield assembly, rear frame assembly, and two side assembly. During the grabbing process, the vision guidance camera 7 takes pictures and compares them with the recorded vehicle model information to determine whether the grabbed sub-assembly model is correct. If the model is determined to be incorrect, the error alarm device automatically alarms and prompts a re-grabbing. If the model is correct, the gripping position is adjusted according to the recorded model information. After grabbing the corresponding sub-assembly, the assembly robot carries the corresponding sub-assembly to the main assembly frame 1.

[0057] S4. After receiving the controller information, the front windshield positioning mechanism 2.1, the rear wall positioning mechanism 2.2, and the two side wall positioning mechanisms 2.3 on the main assembly frame 1 adjust their positioning positions according to the vehicle model information. The four assembly robots carry the sub-assemblies to move to the corresponding adjustable positioning mechanism components 2. The assembly robots fix the rear wall frame gripper 3, the front windshield frame gripper 4, and the two side wall frame grippers 5 to the corresponding front windshield positioning mechanism 2.1, the rear wall positioning mechanism 2.2, and the two side wall positioning mechanisms 2.3, respectively.

[0058] S5. The assembly robot disengages from the corresponding gripper and switches to the welding gun tool, moves to the welding gun parking station to load the welding gun, returns to the main assembly frame 1, and performs spot welding on each sub-assembly after assembly. After welding is completed, the assembly robot moves to the welding gun parking station to disengage from the welding gun, switches the gripper tool to reload the corresponding gripper, and waits for the next assembly.

[0059] S6. The lower body clamp 6 releases the lower body assembly, the main line skid rises, and takes the assembled front windshield assembly, rear bulkhead assembly, left side bulkhead assembly, right side bulkhead assembly and lower body assembly away from the lower body clamp 6 and sends them to the next work station.

[0060] The above embodiments are provided only to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flexible assembly system for the main welding line of a body-in-white, characterized in that, The assembly includes a main frame (1), an adjustable positioning mechanism assembly (2), a rear frame gripper (3), a front windshield frame gripper (4), two side frame grippers (5), and a lower body clamp (6). The main frame (1) is fixedly supported on the ground. The adjustable positioning mechanism assembly (2) is set on the main frame (1) according to the assembly position of the sub-assemblies. It is used to quickly and detachably fix the rear frame gripper (3), the front windshield frame gripper (4), and the two side frame grippers (5) and can adjust the connection position of the grippers according to the vehicle model. The rear frame gripper (3), the front windshield frame gripper (4), the two side frame grippers (5), and the two lower body clamps (6) are all adjustable structures. They are used to fix the front windshield assembly, the rear assembly, the two side assemblies, and the lower body assembly and can adjust the fixing and clamping position of the sub-assemblies according to the vehicle model. The two lower body clamps (6) are symmetrically spaced on the ground inside the main frame (1).

2. The flexible assembly system for the main welding line of the body-in-white according to claim 1, characterized in that, The overall frame (1) includes four frame columns (1.1). The adjustable positioning mechanism assembly (2) includes a front windshield positioning mechanism (2.1), a rear wall positioning mechanism (2.2), and two side wall positioning mechanisms (2.3). The front windshield positioning mechanism (2.1), the rear wall positioning mechanism (2.2), and the two side wall positioning mechanisms (2.3) are used in pairs and symmetrically fixed at the corresponding positions of the frame columns (1.1), respectively for fixing and connecting the rear wall frame grab (3), the front windshield frame grab (4), and the two side wall frame grabs (5).

3. The flexible assembly system for the main welding line of the body-in-white according to claim 2, characterized in that, The front windshield positioning mechanism (2.1) and the rear surround positioning mechanism (2.2) have the same structure, both including a positioning base plate (2.11), a positioning sliding mechanism (2.12), a gripper frame positioning pin (2.13), a gripper frame positioning surface (2.14), a gripper frame three-way limiting block (2.15), an X-axis pressing unit (2.16), and an X-axis and Z-axis bidirectional pressing unit (2.17). The positioning base plate (2.11) is fixed to the corresponding frame column (1.1). The positioning sliding mechanism (2.12) and the gripper frame positioning pin... (2.13), gripper frame positioning surface (2.14), gripper frame three-way limiting block (2.15), X-axis pressing unit (2.16) and X-axis and Z-axis bidirectional pressing unit (2.17) are all set on the positioning small base plate (2.11). The positioning sliding mechanism (2.12) includes a cylinder driving mechanism. The positioning sliding mechanism (2.12) slides under the drive of the cylinder for the positioning adjustment of the front windshield positioning mechanism (2.1) / rear surround positioning mechanism (2.2) in the X-axis. The gripper frame positioning pin (2.13) is used to connect with the corresponding gripper positioning.

4. The flexible assembly system for the main welding line of the body-in-white according to claim 3, characterized in that, The side wall positioning mechanism (2.3) and the front windshield positioning mechanism (2.1) have the same structure, including a positioning base plate, a positioning sliding mechanism, a gripper frame positioning pin, a gripper frame positioning surface, a gripper frame three-way limiting block, a Y-axis pressing unit and a Y-axis and Z-axis bidirectional pressing unit. The Y-axis pressing unit has the same structure as the X-axis pressing unit (2.16) of the front windshield positioning mechanism (2.1), and the Y-axis and Z-axis bidirectional pressing unit has the same structure as the X-axis and Z-axis bidirectional pressing unit (2.17) of the front windshield positioning mechanism (2.1), and is used for the Y-axis positioning adjustment of the side wall positioning mechanism.

5. The flexible assembly system for the main welding line of the body-in-white according to claim 4, characterized in that, The rear frame gripper (3) includes a rear gripper frame (3.1), an X-axis positioning block (3.2), a gripper sliding mechanism (3.3), a frame gripper main positioning unit (3.4), a frame gripper three-axis positioning unit (3.5), a wide vehicle Z-axis upward positioning unit (3.6), a narrow vehicle Z-axis upward positioning unit (3.7), a narrow vehicle Y-axis leftward positioning unit (3.8), a wide vehicle Y-axis leftward positioning unit (3.9), a narrow vehicle Z-axis downward positioning unit (3.10), a wide vehicle Z-axis downward positioning unit (3.11), a narrow vehicle Y-axis rightward positioning unit (3.12), a wide vehicle Y-axis rightward positioning unit (3.13), and a visual guidance camera. The rear gripper frame (3.1) is quickly and detachably fixedly connected to the corresponding adjustable positioning mechanism assembly (2). The X-axis positioning block (3.2), gripper sliding mechanism (3.3), frame gripper main positioning unit (3.4), frame gripper three-way positioning unit (3.5), wide vehicle Z-up positioning unit (3.6), narrow vehicle Z-up positioning unit (3.7), narrow vehicle Y-left positioning unit (3.8), wide vehicle Y-left positioning unit (3.9), narrow vehicle Z-down positioning unit (3.10), wide vehicle Z-down positioning unit (3.11), and narrow vehicle Y-right positioning unit (3.12) are also included. The wide vehicle Y-direction right positioning unit (3.13) and the visual guidance camera (7) are both mounted on the rear grabber frame (3.1). The grabber sliding mechanism (3.3) includes a cylinder drive mechanism. The grabber sliding mechanism (3.3) slides left / right under the drive of the cylinder for the Y-direction positioning adjustment of the rear frame grabber (3). The narrow vehicle Z-direction upward positioning unit (3.7), the wide vehicle Y-direction left positioning unit (3.9), and the wide vehicle Y-direction right positioning unit (3.13) all include a flipping mechanism. The narrow vehicle Z-direction upward positioning unit (3.7) flips up / down for the Z-direction positioning adjustment of the rear frame grabber (3). The wide vehicle Y-direction left positioning unit (3.13) 3.9) and the wide vehicle Y-direction right positioning unit (3.13) flip inward / outward for the Y-position adjustment of the rear frame gripper (3) in the Y direction. The wide vehicle Z-direction downward positioning unit (3.11) includes a cylinder drive mechanism. The wide vehicle Z-direction downward positioning unit (3.11) slides along the Z direction under the cylinder drive for the positioning adjustment of the rear frame gripper (3) in the Z direction. The visual guidance camera (7) is used to take pictures and compare them with the vehicle model information already recorded in the system to determine the correctness of the vehicle model and adjust the gripper position. The frame gripper main positioning unit (3.4) is provided with a positioning hole for positioning connection with the gripper frame positioning pin (2.13).

6. The flexible assembly system for the main welding line of the body-in-white according to claim 5, characterized in that, The windshield frame gripper (4) includes a windshield frame gripper main positioning unit (4.1), a windshield frame gripper three-way positioning unit (4.2), a wide vehicle windshield X-direction and Z-direction bidirectional positioning clamping unit (4.3), a narrow vehicle windshield X-direction and Z-direction bidirectional positioning clamping unit (4.4), a windshield X-direction and Z-direction bidirectional positioning clamping unit (4.5), a windshield main positioning pin (4.6), a narrow vehicle windshield main positioning pin auxiliary positioning pin (4.7), a wide vehicle windshield main positioning pin auxiliary positioning pin (4.8), and a windshield gripper frame (4.9). The windshield frame gripper main positioning unit (4.1), windshield frame gripper three-way positioning unit (4.2), wide vehicle windshield X-direction and Z-direction bidirectional positioning clamping unit (4.3), narrow vehicle windshield X-direction and Z-direction bidirectional positioning clamping unit (4.4), windshield X-direction and Z-direction bidirectional positioning unit (4.5), windshield main positioning pin (4.6), narrow vehicle windshield main positioning pin auxiliary positioning pin (4.7), wide vehicle windshield main positioning pin auxiliary positioning pin (4.8), and windshield gripper frame (4.9) are all part of the windshield frame gripper. The clamping unit (4.5), the main positioning pin of the windshield (4.6), the auxiliary positioning pin of the main positioning pin of the narrow windshield (4.7), and the auxiliary positioning pin of the main positioning pin of the wide windshield (4.8) are respectively set on the windshield gripper frame (4.9). The wide windshield X-direction and Z-direction bidirectional positioning clamping unit (4.3) and the narrow windshield X-direction and Z-direction bidirectional positioning clamping unit (4.4) both include a flipping mechanism. The wide windshield X-direction and Z-direction bidirectional positioning clamping unit (4.3) and the narrow windshield X-direction and Z-direction bidirectional positioning clamping unit (4.4) are flipped according to different vehicle models for the positioning adjustment of the windshield in the X direction. The main positioning pin of the windshield (4.6), the auxiliary positioning pin of the main positioning pin of the narrow windshield (4.7), and the auxiliary positioning pin of the main positioning pin of the wide windshield (4.8) are used for positioning and connection with the corresponding positioning holes on the windshield assembly.

7. The flexible assembly system for the main welding line of the body-in-white according to claim 6, characterized in that, The two side frame grippers (5) have the same structure, including a side main positioning pin (5.1), a side front Y positioning clamping unit (5.2), a side X positioning clamping unit (5.3), a side Z positioning clamping unit (5.4), a side long / short carriage switching sliding mechanism (5.5), a side auxiliary positioning pin (5.6), a side rear Y positioning clamping unit (5.7), a side gripper three-way positioning unit (5.8), a side gripper main positioning unit (5.9), a side gripper frame (5.10), and a visual guidance camera (7). 5) The side auxiliary positioning pin (5.6), the side rear Y-direction positioning clamping unit (5.7), the side gripper three-way positioning unit (5.8), the side gripper main positioning (5.9) and the vision guidance camera (7) are all set on the side gripper frame (5.10). The side main positioning pin (5.1) is used to position and connect with the main positioning hole on the side assembly. The side long and short carriage switching sliding mechanism (5.5) includes a cylinder drive mechanism for adjusting the positioning of the side gripper in the X direction. The side front Y-direction positioning clamping unit (5.2), the side X-direction positioning clamping unit (5.3), the side Z-direction positioning clamping unit (5.4) and the side rear Y-direction positioning clamping unit (5.7) all include a flipping mechanism to achieve the positioning adjustment of the side frame gripper (5) by flipping.

8. The flexible assembly system for the main welding line of the body-in-white according to claim 7, characterized in that, Each underbody fixture (6) includes a fixture base plate (6.1), a floor front end positioning unit (6.2), a narrow vehicle floor rear end positioning unit (6.3), and a wide vehicle rear end positioning unit (6.4). The floor front end positioning unit (6.2), the narrow vehicle floor rear end positioning unit (6.3), and the wide vehicle rear end positioning unit (6.4) are all disposed on the fixture base plate (6.1). The floor front end positioning unit (6.2) and the wide vehicle rear end positioning unit (6.4) both include a cylinder drive mechanism. The floor front end positioning unit (6.2) slides in the Y direction under the cylinder drive for the Y-direction positioning adjustment of the underbody fixture (6). The wide vehicle rear end positioning unit (6.4) slides in the X direction under the cylinder drive for the X-direction positioning adjustment of the underbody fixture (6).

9. The flexible assembly system for the main welding line of the body-in-white according to claim 8, characterized in that, It also includes four assembly robots, a mainline skid, a welding gun parking station, a sub-assembly loading station, an error alarm device, and a controller. Each assembly robot includes a welding gun tool and a gripper tool. The welding gun parking station is used to store welding guns, and the assembly robot can access and retrieve welding guns from the parking station by switching welding gun tools. The sub-assembly loading station is used to store the front windshield assembly, rear bulkhead assembly, and two side bulkhead assemblies. The assembly robot can load the corresponding gripper tool by switching gripper tools and retrieve the corresponding sub-assembly through the corresponding gripper. The main line skid, adjustable positioning mechanism assembly (2), rear frame gripper (3), front windshield frame gripper (4), side frame gripper (5), and lower body clamp (6) are all electrically connected to the controller. The controller includes an RFID reader for reading vehicle model information of the lower body assembly. The main line skid is set on the ground between the two lower body clamps (6). The error alarm device is electrically connected to the controller and is used to issue an alarm when the visual guidance camera (7) finds an error in the grip after comparing the photographed information.

10. A flexible assembly method for the main welding line of a body-in-white, characterized in that, The method for flexible assembly using the flexible assembly system for the main welding line of the body-in-white as described in claim 9 includes the following steps: S1. After the controller reads the vehicle model information of the lower body assembly transported by the main line skid through the RFID reader, it sends the information to the assembly robot, the adjustable positioning mechanism component (2), the rear frame gripper (3), the front windshield frame gripper (4), the side frame gripper (5), and the lower body clamp (6). S2. The lower body assembly is transported to the two lower body clamps (6) of the main assembly frame (1) via the main line skid. The lower body clamps (6) adjust their positioning position according to the vehicle model information. The main line skid descends and the lower body assembly falls from the main line skid into the lower body clamps (6) and is clamped and fixed. S3, the rear frame gripper (3), the front windshield frame gripper (4) and the two side frame grippers (5) adjust their positioning positions according to the vehicle model information. The four assembly robots switch gripper tools respectively to load the corresponding rear frame gripper (3), front windshield frame gripper (4) and two side frame grippers (5) and move them to the sub-assembly loading station. The rear frame gripper (3), front windshield frame gripper (4) and two side frame grippers (5) respectively grab the corresponding front windshield assembly, rear frame assembly and two side assembly. During the grabbing process, the visual guidance camera (7) takes pictures and compares them with the vehicle model information that has been entered to determine whether the vehicle model of the grabbed sub-assembly is correct. If the vehicle model is determined to be incorrect, the error alarm device will automatically alarm and prompt for re-grabbing. If the vehicle model is correct, the gripping position is adjusted according to the vehicle model information that has been entered. After the corresponding sub-assembly is grabbed, the assembly robot carries the corresponding sub-assembly to the assembly frame (1). S4. After receiving the controller information, the front windshield positioning mechanism (2.1), rear wall positioning mechanism (2.2) and two side wall positioning mechanisms (2.3) on the main assembly frame (1) adjust their positioning positions according to the vehicle model information. The four assembly robots carry the sub-assemblies to the corresponding adjustable positioning mechanism components (2). The assembly robots fix the rear wall frame gripper (3), front windshield frame gripper (4) and two side wall frame grippers (5) to the corresponding front windshield positioning mechanism (2.1), rear wall positioning mechanism (2.2) and two side wall positioning mechanisms (2.3) respectively. S5. The assembly robot disengages from the corresponding gripper and switches to the welding gun tool, moves to the welding gun parking station to load the welding gun, returns to the main assembly frame (1), and performs spot welding on each sub-assembly after assembly. After welding is completed, the assembly robot moves to the welding gun parking station to disengage from the welding gun, and the assembly robot switches to the gripper tool to reload the corresponding gripper and waits for the next assembly. S6. The lower body clamp (6) releases the lower body assembly, the main line skid rises, and takes the assembled front windshield assembly, rear bulkhead assembly, left side bulkhead assembly, right side bulkhead assembly and lower body assembly away from the lower body clamp (6) and sends them to the next work station.

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