Multi-station welding forming device for automobile C column inner plate assembly

Abstract

The invention relates to the technical field of automobile sheet metal part welding, and discloses an automobile C column inner plate assembly multi-station welding forming device which comprises a welding spot grouping and path optimizing module used for grouping input welding spot data information and calculating and outputting optimal welding path coordinate data; the PLC system is used for receiving the optimal welding path coordinate data, calculating the optimal welding path coordinate data, temporarily storing the optimal welding path coordinate data into the PLC system, and outputting a welding instruction through the Profibus-DP communication bus when the PLC system is called; and the welding module is used for responding to the welding instruction and executing a welding action. According to the welding spot grouping and path optimization module developed on the basis of a Matlab platform, the problem that residual stress distribution is uneven in the welding process is solved, the problem that a thermal field is unbalanced is also solved, the welding efficiency is improved, and the welding quality is improved. And the piezoelectric ceramic sensors arranged in the clamping areas of the feeding clamp trigger the PLC system to dynamically adjust the clamping pressure of the corresponding clamping areas of the feeding clamp so as to compensate thermal deformation displacement and restrain deformation.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile sheet metal part welding, and specifically to a multi-station welding forming device for an inner panel assembly of an automobile C-pillar. Background Technique

[0002] As a key load-bearing component of the vehicle body structure, the inner panel assembly of the automobile C-pillar is usually made of high-strength steel plates (such as HC340 / 590DP) after stamping, and is formed by connecting the base plate, reinforcing ribs and flanging structures through multiple weld points. Its welding quality directly affects the vehicle body safety, NVH performance and assembly quality.

[0003] Especially during the welding process in the multi-weld point area, the local high temperature (such as the instantaneous temperature of resistance spot welding can reach 1500 °C) causes uneven thermal expansion of the base plate inside the C-pillar assembly, and shrinkage stress is generated after cooling. And when the multi-weld points are densely distributed, the adjacent heat affected zones overlap, forming a "thermal input chain reaction", which intensifies longitudinal shrinkage, angular deformation and wavy deformation.

[0004] However, the existing welding devices usually adopt a fixed welding path, without considering the grouping of weld points and the balance of the thermal field, resulting in uneven distribution of residual stress and local sheet metal deformation. Secondly, the traditional fixture adopts a uniform clamping force and cannot dynamically suppress the local stress change during the welding process, resulting in constraint failure. Especially in the flanging area, the welding thermal cycle reduces the yield strength of the material, intensifying plastic deformation. Therefore, there is an urgent need for a multi-station welding forming device for an inner panel assembly of an automobile C-pillar to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-station welding forming device for an inner panel assembly of an automobile C-pillar to solve the problems in the above background technique that the existing welding devices usually adopt a fixed welding path, without considering the grouping of weld points and the balance of the thermal field, resulting in uneven distribution of residual stress and local sheet metal deformation; secondly, the traditional fixture adopts a uniform clamping force and cannot dynamically adapt to the local stress change during the welding process, resulting in constraint failure. In the flanging area, the welding thermal cycle reduces the yield strength of the material, intensifying plastic deformation.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A multi-station welding forming device for an inner panel assembly of an automobile C-pillar, including: a weld point grouping and path optimization module, used for grouping the input weld point data information and calculating and outputting the optimal welding path coordinate data; A PLC system and a Profibus-DP communication bus, the PLC system is used to receive the optimal welding path coordinate data, calculate and temporarily store it internally, and when called, output a welding instruction through the Profibus-DP communication bus; A welding module, the welding module is used to respond to the welding instruction and perform welding actions; A feeding module, a piezoelectric ceramic sensor and an industrial control computer, wherein the feeding module includes a feeding fixture; Among them, the feeding module is used for automatically feeding and supplying the total body of the C-pillar inner panel, the piezoelectric ceramic sensor is used for detecting the clamping pressure data of each clamping area of the feeding fixture, and the industrial control computer is used for receiving the clamping pressure data and transmitting it to the PLC system through the Modbus TCP protocol; Among them, the welding module is arranged in the middle of the feeding module. During the welding operation of the welding module, when the clamping pressure data exceeds the rated threshold, the PLC system is triggered to send an instruction to the feeding fixture through the Profibus-DP communication bus to dynamically adjust the clamping pressure of the corresponding clamping area of the total body of the C-pillar inner panel in the feeding fixture.

[0007] As a further preference of this technical solution: the solder joint grouping and path optimization module includes a solder joint information input unit, a solder joint grouping unit, a welding path optimization algorithm, and an optimal path output unit; Among them, the solder joint information input unit is used for receiving the solder joint data of the total body of the C-pillar inner panel and transmitting the solder joint data to the solder joint grouping unit for grouping. The solder joint data are n solder joints on the total body of the C-pillar inner panel , and there are m welding robots arranged in the welding module ; Among them, for n solder joints , some solder joints that need to be symmetrically welded to reduce the longitudinal displacement of the welded part are preset as a group; Among them, for n solder joints , for the small-area multi-solder joint area, the solder joints that need to be spaced and staggered are preset as a group; The grouping mathematical model in the solder joint grouping unit is: (1) Solder joint grouping constraint conditions: (2) (3) (4) Among them, is the best solder joint allocation result of multiple welding robots in this total welding forming device, is the distance of the solder joint from the welding robot to which it is allocated, represents the spatial range of the welding working area of the welding robot , represents the maximum radius of the spatial range of the welding working area, represents the minimum radius of the spatial range of the welding working area. Formula (1) represents the shortest distance between the solder joint and the welding robot. Formulas (2) and (3) represent that each solder joint is only assigned to one robot. Formula (4) represents the upper and lower limits of the number of solder joints assigned to each robot.

[0008] As a further preference of this technical solution: The welding path optimization algorithm is used to receive the n solder joint grouping result data output by the solder joint grouping unit and construct a path optimization objective function with the goal of the shortest robot welding path. After logical operation, it outputs the shortest global welding path parameters. The path optimization objective function is: (5) In formula (5), represents the shortest global welding path, represents the distance between two adjacent solder joints and the distance between represents the distance between the first solder joint and the last solder joint.

[0009] As a further preference of this technical solution: The optimal path output unit is used to receive the shortest global welding path parameters output by the welding path optimization algorithm and transmit them to the PLC system. Among them, the PLC system includes a power supply module, a CPU module, an IO signal module, a storage module, and a communication module. The power supply module is used to provide power to the entire PLC system. The IO signal module is used to receive the shortest global welding path parameters and transmit them to the storage module through calculation by the CPU module to temporarily store the welding instruction data. When the welding instruction data is called by the CPU, the PLC system sends a welding instruction to the welding module through the Profibus-DP communication bus.

[0010] As a further preference of this technical solution: The welding module includes a first welding robot and a second welding robot. A first welding torch is provided on the first welding robot, and a second welding torch is provided on the second welding robot. Among them, the first welding robot is used to receive the welding instruction, perform logical calculation, and then send a driving instruction to the motor to adjust the rotation angle pose and movement trajectory. The first welding robot is also used to receive the welding instruction, perform logical calculation, and then send a welding instruction to the first welding torch to output the welding voltage and welding current, and the first welding torch executes the welding task on the total body of the inner panel of the C-pillar.

[0011] As a further preference of this technical solution: The second welding robot is used to receive the welding instruction, perform logical calculation, and then send a driving instruction to the motor to adjust the rotation angle pose and movement trajectory. Among them, the second welding robot is further configured to receive the welding instruction, perform logical calculation, and then send a welding instruction to the second welding torch to output welding voltage and welding current, and the second welding torch executes the welding task on the total body of the inner panel of the C-pillar.

[0012] As a further preferred embodiment of this technical solution: The storage module in the PLC system also stores the feeding program data. The CPU module is used to call the feeding program data, perform logical operations, and then send a feeding instruction to the feeding module through the Profibus-DP communication bus. The feeding module is used to receive the feeding instruction, perform calculations, and then execute feeding, material supply, and clamping actions.

[0013] As a further preferred embodiment of this technical solution: The feeding module includes a first feeding production line and a second feeding production line. A first feeding fixture is arranged on the first feeding production line, and a second feeding fixture is arranged on the second feeding production line; Among them, the first feeding production line and the second feeding production line receive the feeding instruction and execute the automatic feeding action of the production line.

[0014] As a further preferred embodiment of this technical solution: The feeding module further includes a first feeding robot and a second feeding robot; Among them, the first feeding robot and the second feeding robot are used to receive the feeding instruction and then execute the feeding and handling function for the total body of the inner panel of the C-pillar; Among them, the feeding fixture is used to receive the feeding instruction and then execute the clamping function for the total body of the inner panel of the C-pillar; Both the first feeding robot and the second feeding robot are arranged between the first feeding production line and the second feeding production line, and the feeding fixture is arranged between the first feeding robot and the second feeding robot; The feeding fixture is also arranged between the first welding robot and the second welding robot.

[0015] As a further preferred embodiment of this technical solution: The piezoelectric ceramic sensor is arranged on the feeding fixture, and multiple groups of piezoelectric ceramic sensors are provided.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. In the present invention, the solder joint grouping and path optimization module developed based on the Matlab platform first groups the solder joint information data of the total C-pillar inner panel imported. Among them, continuous solder joints are grouped alternately, some solder joints are grouped symmetrically, and solder joints without obvious geometric distribution characteristics and process requirements are grouped independently. The grouped data output by the solder joint grouping unit not only solves the problem of uneven residual stress distribution during the welding process, but also solves the problem of uneven thermal field through the skip welding method of symmetric grouping, thereby achieving the technical effect of the optimal distribution of solder joints on the total C-pillar inner panel and effectively improving the welding quality. 2. The welding path optimization algorithm in the solder joint grouping and path optimization module of the present invention receives the solder joint grouping parameters output from the welding grouping unit, and outputs the optimal welding path coordinate data to the PLC system after logical operation based on the Matlab platform and the path optimization objective function. The PLC system issues welding instructions, and the first welding robot and the second welding robot respond to the welding instructions to achieve the coordinated welding function of the two robots. Since the welding path optimization algorithm constructs the shortest global welding path, the welding efficiency and production rhythm are improved. 3. Piezoelectric ceramic sensors are provided in each clamping area of the feeding fixture in the present invention, which are used to detect the clamping pressure data of each clamping area of the feeding fixture. The industrial control computer is used to receive the clamping pressure data and transmit it to the PLC system through the Modbus TCP protocol. During the welding process, when the clamping pressure data exceeds the rated threshold, the PLC system is triggered to send an instruction to the feeding fixture through the Profibus-DP communication bus, and then dynamically adjusts the clamping pressure of the corresponding clamping area of the total C-pillar inner panel in the feeding fixture to compensate for the thermal deformation displacement and suppress the local stress change during the welding process, thereby suppressing deformation. 4. The feeding module in the present invention receives the timing control instruction sent by the PLC system through the Profibus-DP communication bus, controls the orderly operation of the entire system, and ensures that after the first feeding production line drives the first feeding fixture forward by a preset number of steps, the first feeding robot clamps the total C-pillar inner panel in the first feeding fixture, turns it to the feeding fixture and places it. After the feeding fixture clamps the total C-pillar inner panel, it provides welding conditions for the welding module. After the PLC system receives the pressure signal from the piezoelectric ceramic sensor, it executes the welding instruction. The second feeding production line also executes the timing control instruction, and the two production lines supply materials in sequence, ensuring the feeding efficiency and quality and improving the welding rate. Description of the Drawings

[0017] Figure 1 is a three-dimensional structural schematic diagram of a multi-station welding forming device for an automobile C-pillar inner panel assembly of the present invention; Figure 2 is Figure 1 an enlarged structural schematic diagram at A in Figure 3 isFigure 1 Schematic diagram of the enlarged structure at B in the [Chinese context]; Figure 4 Schematic diagram of the operation framework of a multi-station welding forming device for the inner panel assembly of an automotive C-pillar according to the present invention; Figure 5 Flowchart of the operation of the solder joint grouping and path optimization module in a multi-station welding forming device for the inner panel assembly of an automotive C-pillar according to the present invention; Figure 6 Flowchart of the operation of the welding path optimization algorithm in a multi-station welding forming device for the inner panel assembly of an automotive C-pillar according to the present invention; Figure 7 Schematic diagram of the module structure of the PLC system in a multi-station welding forming device for the inner panel assembly of an automotive C-pillar according to the present invention; Figure 8 Flowchart of the operation of a multi-station welding forming device for the inner panel assembly of an automotive C-pillar according to the present invention. In the figure: 10, the first feeding robot; 20, the second feeding robot; 30, the first welding robot; 301, the first welding torch; 40, the second welding robot; 401, the second welding torch; 50, the first feeding production line; 501, the first feeding fixture; 60, the second feeding production line; 601, the second feeding fixture; 70, the feeding fixture; 80, the piezoelectric ceramic sensor; 90, the main body of the inner panel of the C-pillar. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0020] Embodiment In order to solve the problems that existing welding devices, on the one hand, mostly adopt fixed welding paths and do not consider solder joint grouping and thermal field balance, resulting in uneven distribution of residual stress and local sheet metal deformation; on the other hand, traditional fixtures adopt uniformly distributed clamping forces and cannot dynamically suppress local stress changes during welding, resulting in constraint failure, in the embodiments of the present application, a multi-station welding forming device for the inner panel assembly of an automotive C-pillar is designed, asFigures 1 - 7 As shown in the figure, it includes: a solder joint grouping and path optimization module, which is used to group the input solder joint data information, calculate and output the optimal welding path coordinate data; The solder joint grouping and path optimization module developed based on the Matlab platform first groups the solder joint information data of the total inner panel 90 of the C-pillar. Among them, continuous solder joints are grouped alternately, some solder joints are grouped symmetrically, and solder joints without obvious geometric distribution characteristics and process requirements are grouped independently. The grouped data output by the solder joint grouping unit not only solves the problem of uneven residual stress distribution during the welding process, but also solves the problem of uneven thermal field through the skip welding method of symmetric grouping. Thus, the technical effect of the optimal distribution of the solder joints of the total inner panel 90 of the C-pillar is achieved, effectively improving the welding quality.

[0021] As Figure 4 shown in the figure, a PLC system and a Profibus-DP communication bus. The PLC system is used to receive the optimal welding path coordinate data, temporarily store it internally, and output welding instructions through the Profibus-DP communication bus when called; As Figure 4 shown in the figure, a welding module, which is used to respond to welding instructions and perform welding actions; As Figure 4 shown in the figure, a feeding module, a piezoelectric ceramic sensor and an industrial control computer. The feeding module includes a feeding fixture 70; As Figure 4 and Figure 3 shown in the figure, among which, the feeding module is used to automatically feed and supply the total inner panel 90 of the C-pillar, the piezoelectric ceramic sensor 80 is used to detect the clamping pressure data of each clamping area of the feeding fixture 70, and the industrial control computer is used to receive the clamping pressure data and transmit it to the PLC system through the Modbus TCP protocol; As Figure 1 , Figure 2 and Figure 4 shown in the figure, among which, the welding module is set in the middle of the feeding module. During the welding action of the welding module, when the clamping pressure data exceeds the rated threshold, it triggers the PLC system to send instructions to the feeding fixture 70 through the Profibus-DP communication bus to dynamically adjust the clamping pressure of the corresponding clamping area of the total inner panel 90 of the C-pillar in the feeding fixture 70.

[0022] In this embodiment, as Figure 5 shown in the figure, the solder joint grouping and path optimization module includes a solder joint information input unit, a solder joint grouping unit, a welding path optimization algorithm and an optimal path output unit; Among them, the solder joint information input unit is used to receive the solder joint data of the total C-pillar inner panel body 90 and transmit the solder joint data to the solder joint grouping unit for grouping. The solder joint data are n solder joints on the total C-pillar inner panel body 90 , and there are m welding robots set in the welding module ; Among them, for the n solder joints , some of the solder joints that need to be symmetrically welded to reduce the longitudinal displacement of the welded parts are preset as a group; Among them, for the n solder joints , for the small-area multi-solder-joint area, the solder joints that need to be spaced and staggered are preset as a group; The grouping mathematical model in the solder joint grouping unit is: (1) Solder joint grouping constraint conditions: (2) (3) (4) Among them, is the optimal solder joint allocation result of multiple welding robots in this total welding forming device, is the distance from the solder joint to the welding robot , represents the spatial range of the welding working area of the welding robot , represents the maximum radius of the spatial range of the welding working area, represents the minimum radius of the spatial range of the welding working area. Formula (1) means that the distance between the solder joint and the welding robot is the shortest. Formulas (2) and (3) mean that a single solder joint is only allocated to one robot. Formula (4) means to limit the upper and lower limits of the number of solder joints allocated to each robot.

[0023] In this embodiment, as Figure 6 shown, the welding path optimization algorithm is used to receive the n solder joint grouping result data output by the solder joint grouping unit and construct a path optimization objective function with the shortest robot welding path as the goal. After logical operation, the shortest global welding path parameters are output; The path optimization objective function is: (5) In formula (5), represents the shortest global welding path, represents the distance between two adjacent solder joints and , Indicates the distance between the first solder joint and the last solder joint.

[0024] Among them, as Figure 6 shown, the welding path optimization algorithm includes the following steps: A1. Receive the solder joint parameters output from the solder joint grouping unit and initialize the algorithm; A2. Based on the process requirements, construct a local welding path to suppress deformation displacement; A3. After the local welding path is constructed, update the local pheromone, otherwise reconstruct the local welding path; A4. After the local pheromone is updated, further implement the global pheromone update; A5. After the global pheromone is updated, finally construct and output the shortest global welding path.

[0025] The welding path optimization algorithm in the solder joint grouping and path optimization module receives the solder joint grouping parameters output from the welding grouping unit. After logical operations based on the Matlab platform and the path optimization objective function, it outputs the optimal welding path coordinate data to the PLC system. The PLC system issues welding instructions, and the first welding robot 30 and the second welding robot 40 respond to the welding instructions to achieve the coordinated welding function of the dual robots. Since the welding path optimization algorithm constructs the shortest global welding path, the welding efficiency and production rhythm are improved.

[0026] As Figure 5 shown, the optimal path output unit is used to receive the shortest global welding path parameters output by the welding path optimization algorithm and transmit them to the PLC system; Among them, as Figure 4 and Figure 7 shown, the PLC system includes a power supply module, a CPU module, an IO signal module, a storage module, and a communication module. The power supply module is used to provide power to the entire PLC system. The IO signal module is used to receive the shortest global welding path parameters and transmit them to the storage module through calculation by the CPU module to temporarily store the welding instruction data. When the welding instruction data is called by the CPU, the PLC system sends welding instructions to the welding module through the Profibus-DP communication bus.

[0027] In this embodiment, as Figure 1 , Figure 2 and Figure 4 shown, the welding module includes a first welding robot 30 and a second welding robot 40. A first welding torch 301 is provided on the first welding robot 30, and a second welding torch 401 is provided on the second welding robot 40; Among them, the first welding robot 30 is used to receive welding instructions, perform logical calculations, and send drive instructions to the motor to adjust the rotation angle, pose, and movement trajectory; The first welding robot 30 is also used to receive welding instructions, perform logic calculations, send welding instructions to the first welding torch 301, output welding voltage and welding current, and the first welding torch 301 executes the welding task on the overall body 90 of the C-pillar inner panel.

[0028] The second welding robot 40 is used to receive welding instructions, perform logic calculations, send driving instructions to the motor, and adjust the rotation angle, pose, and movement trajectory; Among them, as Figure 1 and Figure 2 shown, the second welding robot 40 is also used to receive welding instructions, perform logic calculations, send welding instructions to the second welding torch 401, output welding voltage and welding current, and the second welding torch 401 executes the welding task on the overall body 90 of the C-pillar inner panel.

[0029] As Figure 4 and Figure 7 shown, the storage module in the PLC system also stores the feeding program data. The CPU module is used to call the feeding program data, perform logic operations, and send feeding instructions to the feeding module through the Profibus-DP communication bus. The feeding module is used to receive the feeding instructions, perform calculations, and execute feeding, material supply, and clamping actions.

[0030] The multi-station welding forming device for the automobile C-pillar inner panel assembly in the embodiment of the present application can be applied in the process of automobile sheet metal welding. Specifically, the automobile sheet metal is not limited to the overall body 90 of the C-pillar inner panel, the front longitudinal beam assembly, the overall body of the A-pillar inner panel, etc.

[0031] In this embodiment, as Figure 1 and Figure 3 shown, the feeding module includes a first feeding production line 50 and a second feeding production line 60. A first feeding fixture 501 is arranged on the first feeding production line 50, and a second feeding fixture 601 is arranged on the second feeding production line 60; Piezoelectric ceramic sensors 80 are arranged in each clamping area of the feeding fixture 70. They are used to detect the clamping pressure data of each clamping area of the feeding fixture 70. The industrial control computer is used to receive the clamping pressure data and transmit it to the PLC system through the Modbus TCP protocol. During the welding process, when the strain pressure data exceeds the rated threshold, it triggers the PLC system to send instructions to the feeding fixture 70 through the Profibus-DP communication bus, and then dynamically adjusts the clamping pressure of the corresponding clamping area of the feeding fixture 70 for the overall body 90 of the C-pillar inner panel to compensate for the thermal deformation displacement, suppress the local stress change during the welding process, and thus suppress deformation; Among them, the first feeding production line 50 and the second feeding production line 60 receive the feeding instructions and execute the automatic feeding action of the production line.

[0032] In this embodiment, as Figure 1 、Figure 2 and Figure 3 As shown in Figure 3 , the feeding module further includes a first feeding robot 10 and a second feeding robot 20; Among them, the first feeding robot 10 and the second feeding robot 20 are used to perform the feeding and handling function of the total body 90 of the C-pillar inner panel after receiving the feeding instruction; Among them, as Figure 2 shown, the feeding fixture 70 is used to perform the clamping function of the total body 90 of the C-pillar inner panel after receiving the feeding instruction; As Figure 1 and Figure 2 shown, both the first feeding robot 10 and the second feeding robot 20 are arranged between the first feeding production line 50 and the second feeding production line 60, and the feeding fixture 70 is arranged between the first feeding robot 10 and the second feeding robot 20; Among them, the feeding module receives the timing control instruction sent by the PLC system through the Profibus-DP communication bus, controls the orderly operation of the whole system, ensures that after the first feeding production line 50 drives the first feeding fixture 501 to advance a preset number of steps, the first feeding robot 10 clamps the total body 90 of the C-pillar inner panel in the first feeding fixture 501, turns it to the feeding fixture 70 and places it. After the feeding fixture 70 clamps the total body 90 of the C-pillar inner panel, it provides welding conditions for the welding module. After the PLC system receives the pressure signal from the piezoelectric ceramic sensor 80, it executes the welding instruction. The second feeding production line 60 also executes the timing control instruction, and the two production lines supply materials in sequence, ensuring the feeding efficiency and quality and improving the welding speed.

[0033] As Figure 1 and Figure 2 shown, the feeding fixture 70 is also arranged between the first welding robot 30 and the second welding robot 40.

[0034] In this embodiment, as Figure 2 shown, the piezoelectric ceramic sensor 80 is arranged on the feeding fixture 70, and there are multiple groups of piezoelectric ceramic sensors 80.

[0035] In order to more clearly understand the working process of a multi-station welding forming device for an automobile C-pillar inner panel assembly according to an embodiment of the present application, refer to Figures 1 - 8 , and the following is a detailed description with a specific embodiment: When running for the first time, welding parameters and feeding parameters are preset on the PLC system. The solder joint information data on the total C-pillar inner panel 90 is imported into the Matlab platform. The solder joint grouping and path optimization module developed on the Matlab platform receives the solder joint information data, performs logical operations, and outputs the solder joint path coordinate data. The PLC system responds to the solder joint path coordinate data from the solder joint grouping and path optimization module, performs calculations through the CPU module, and outputs the welding instructions, which are temporarily stored in the storage module within the PLC system. Secondly, the CPU module in the PLC system calls the feeding program data on the storage module, calculates, and sends a feeding instruction to the feeding module through the Profibus-DP communication bus. The first feeding production line 50 and the second feeding production line 60 receive the above feeding instruction and execute the automatic feeding function. Specifically, the first feeding production line 50 drives the first feeding fixture 501 forward by a preset number of steps, and then the first feeding robot 10 clamps the total C-pillar inner panel 90 in the first feeding fixture 501, turns it to the feeding fixture 70, and places it. Similarly, the second feeding production line 60 drives the second feeding fixture 601 forward by a preset number of steps, and then the second feeding robot 20 clamps the total C-pillar inner panel 90 in the second feeding fixture 601, turns it to the feeding fixture 70, and places it. Then, the feeding fixture 70 responds to the feeding instruction sent by the PLC system through the Profibus-DP communication bus, and clamps the total C-pillar inner panel 90 with uniform pressure in each clamping area. Since piezoelectric ceramic sensors 80 are provided in each clamping area of the feeding fixture 70, after the piezoelectric ceramic sensors 80 obtain the clamping pressure values of each clamping area of the feeding fixture 70, the industrial control computer receives the pressure signals of the piezoelectric ceramic sensors 80 and transmits them to the PLC system through the Modbus TCP protocol. After the PLC system responds to the pressure signals of the piezoelectric ceramic sensors 80, the welding conditions are ready, and the PLC system calls the welding instructions on the storage module through the CPU module. Finally, the first welding robot 30 receives the welding instruction, calculates, drives, adjusts its posture, and then controls the welding voltage and welding current output by the first welding torch 301 to perform the welding task on the total C-pillar inner panel 90. The second welding robot 40 receives the welding instruction, calculates, drives, adjusts its posture, and then controls the welding voltage and welding current output by the second welding torch 401 to perform the welding task on the total C-pillar inner panel 90. During the welding process, when the pressure data of individual clamping areas obtained by the piezoelectric ceramic sensors 80 exceeds the rated threshold, it triggers the PLC system to send an instruction to the feeding fixture 70 through the Profibus-DP communication bus to increase the clamping pressure of the corresponding clamping area, thereby dynamically adjusting the corresponding clamping force of the total C-pillar inner panel 90 in the feeding fixture 70, compensating for the thermal deformation displacement, and suppressing deformation.

[0036] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-station welding and forming device for the inner panel assembly of an automobile C-pillar, characterized in that: Including: A solder joint grouping and path optimization module, which is used to group the input solder joint data information and calculate and output the optimal welding path coordinate data; A PLC system and a Profibus-DP communication bus. The PLC system is used to receive the optimal welding path coordinate data, temporarily store it internally, and when called, output welding instructions through the Profibus-DP communication bus; A welding module, which is used to respond to the welding instructions and perform welding actions; A feeding module, a piezoelectric ceramic sensor, and an industrial control computer. The feeding module includes a feeding fixture; Among them, the feeding module is used to automatically feed and supply the total body of the C-pillar inner panel. The piezoelectric ceramic sensor is used to detect the clamping pressure data of each clamping area of the feeding fixture. The industrial control computer is used to receive the clamping pressure data and transmit it to the PLC system through the Modbus TCP protocol; Among them, the welding module is arranged in the middle of the feeding module. During the welding action of the welding module, when the clamping pressure data exceeds the rated threshold, it triggers the PLC system to send an instruction to the feeding fixture through the Profibus-DP communication bus to dynamically adjust the clamping pressure of the corresponding clamping area of the total body of the C-pillar inner panel in the feeding fixture.

2. The multi-station welding and forming device for the inner panel assembly of the C-pillar of an automobile according to claim 1, wherein: The solder joint grouping and path optimization module includes a solder joint information input unit, a solder joint grouping unit, a welding path optimization algorithm, and an optimal path output unit; Among them, the solder joint information input unit is used to receive the solder joint data of the total C-pillar inner panel body and transmit the solder joint data to the solder joint grouping unit for grouping. The solder joint data are n solder joints on the total C-pillar inner panel body , and m welding robots are arranged in the welding module ; Among them, n solder joints Among them, some of the solder joints that need to be symmetrically welded to reduce the longitudinal displacement of the welded parts are preset as a group; Among them, n solder joints In , for a small-area multi-solder-joint region, the spaced and staggered solder joints are preset as a group; The grouping mathematical model in the solder joint grouping unit is: （1） Solder joint grouping constraint conditions: （2） （3） （4） Among them, is the optimal solder joint allocation result of multiple welding robots in this total welding forming device, is the solder joint distance to the welding robot distance, represents the welding robot welding working area spatial range, represents the maximum radius of the welding working area spatial range, represents the minimum radius of the welding working area spatial range. Formula (1) represents the shortest distance between the solder joint and the welding robot. Formulas (2) and (3) represent that a single solder joint is only allocated to one robot. Formula (4) represents the upper and lower limits of the number of solder joints allocated to each robot.

3. The multi-station welding and forming device for the inner panel assembly of the C-pillar of an automobile according to claim 2, wherein: The welding path optimization algorithm is used to receive the n solder joint grouping result data output by the solder joint grouping unit, construct a path optimization objective function with the shortest robot welding path as the goal, perform logical operations, and output the shortest global welding path parameters; The path optimization objective function is: （5） In formula (5), represents the shortest global welding path, represents the distance between two adjacent welding points and respectively, and represents the distance between the first welding point and the last welding point.

4. The multi-station welding and forming device for the inner panel assembly of the C-pillar of an automobile according to claim 2, wherein: The optimal path output unit is used to receive the shortest global welding path parameters output by the welding path optimization algorithm and transmit them to the PLC system; Among them, the PLC system includes a power supply module, a CPU module, an IO signal module, a storage module, and a communication module. The power supply module is used to provide power to the entire PLC system. The IO signal module is used to receive the shortest global welding path parameters, calculate them through the CPU module, and transmit them to the storage module to temporarily store the welding instruction data. When the welding instruction data is called by the CPU, the PLC system sends a welding instruction to the welding module through the Profibus-DP communication bus.

5. The multi-station welding forming device for the inner panel assembly of the C-pillar of an automobile according to claim 4, wherein: The welding module includes a first welding robot and a second welding robot. A first welding torch is arranged on the first welding robot, and a second welding torch is arranged on the second welding robot; Among them, the first welding robot is used to receive the welding instruction, perform logical calculations, and send a driving instruction to the motor to adjust the rotation angle position and movement trajectory; The first welding robot is also used to receive the welding instruction, perform logical calculations, and send a welding instruction to the first welding torch to output welding voltage and welding current, and the first welding torch executes the welding task of the total body of the C-pillar inner panel.

6. The multi-station welding forming device for the inner panel assembly of the C-pillar of an automobile according to claim 5, wherein: The second welding robot is used to receive the welding instruction, perform logic calculation, and then send a driving instruction to the motor to adjust the rotation angle, pose, and movement trajectory. Among them, the second welding robot is also used to receive the welding instruction, perform logic calculation, and then send a welding instruction to the second welding torch to output welding voltage and welding current, and the second welding torch is used to perform the welding task on the total body of the inner panel of the C-pillar.

7. The multi-station welding forming device for the inner panel assembly of the C-pillar of an automobile according to claim 6, characterized in that: The storage module in the PLC system also stores the data for the feeding program. The CPU module is used to call the data for the feeding program, perform logic operation, and then send a feeding instruction to the feeding module through the Profibus-DP communication bus. The feeding module is used to receive the feeding instruction, perform calculation, and then execute the feeding, material supply, and clamping actions.

8. The multi-station welding forming device for the inner panel assembly of the C-pillar of an automobile according to claim 7, characterized in that: The feeding module includes a first feeding production line and a second feeding production line. A first feeding fixture is arranged on the first feeding production line, and a second feeding fixture is arranged on the second feeding production line. Among them, the first feeding production line and the second feeding production line receive the feeding instruction and execute the automatic feeding action of the production line.

9. The multi-station welding forming device for the inner panel assembly of the C-pillar of an automobile according to claim 8, wherein: The feeding module further includes a first feeding robot and a second feeding robot. Among them, the first feeding robot and the second feeding robot are used to receive the feeding instruction and then perform the feeding and handling function on the total body of the inner panel of the C-pillar. Among them, the feeding fixture is used to receive the feeding instruction and then perform the clamping function on the total body of the inner panel of the C-pillar. Both the first feeding robot and the second feeding robot are arranged between the first feeding production line and the second feeding production line, and the feeding fixture is arranged between the first feeding robot and the second feeding robot. The feeding fixture is also arranged between the first welding robot and the second welding robot.

10. The multi-station welding and forming device for the inner panel assembly of the C-pillar of an automobile according to claim 9, characterized in that: The piezoelectric ceramic sensor is arranged on the feeding fixture, and multiple groups of piezoelectric ceramic sensors are provided.

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