A multi-station welding and forming device for automobile C-pillar inner panel assembly

Abstract

The present invention relates to the technical field of automobile sheet metal welding, and discloses a multi-station welding forming device for an automobile C-pillar inner panel assembly, comprising a welding point grouping and path optimization module for grouping input welding point data information and calculating and outputting optimal welding path coordinate data; a PLC system and a Profibus-DP communication bus, wherein the PLC system is used to receive the optimal welding path coordinate data and temporarily store it internally after calculation, and when called, output a welding instruction via the Profibus-DP communication bus; and a welding module, wherein the welding module is used to respond to the welding instruction and execute a welding action. The welding point grouping and path optimization module developed by the present invention based on the Matlab platform not only solves the problem of uneven residual stress distribution during welding, but also solves the problem of thermal field imbalance, and improves welding efficiency. The piezoelectric ceramic sensors provided in each clamping area of the feed fixture trigger the PLC system to dynamically adjust the clamping pressure of the corresponding clamping area of the feed fixture to compensate for thermal deformation displacement and suppress deformation.

Description

Technical Field

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

[0002] As a key load-bearing component of the vehicle body structure, the C-pillar inner panel assembly is typically formed from high-strength steel plates (such as HC340 / 590DP) through stamping. The base plate, reinforcement ribs, and flange structure are connected through multiple weld points. The quality of the welding directly affects the vehicle body safety, NVH performance, and assembly quality.

[0003] Especially during the welding process in areas with multiple weld points, local high temperatures (such as the instantaneous temperature of resistance spot welding can reach 1500°C) cause uneven thermal expansion of the base plate within the C-pillar assembly, generating shrinkage stress after cooling. Moreover, when multiple weld points are densely distributed, adjacent heat-affected zones overlap, forming a "heat input chain reaction", which aggravates longitudinal shrinkage, angular deformation and wave deformation.

[0004] However, existing welding devices often use fixed welding paths, failing to consider weld point grouping and thermal field balancing. This results in uneven residual stress distribution and localized sheet metal deformation. Furthermore, conventional fixtures employ uniform clamping force, failing to dynamically suppress localized stress variations during welding, leading to constraint failure. This is particularly true in the flanged area, where the welding thermal cycle reduces the material's yield strength and exacerbates plastic deformation. Therefore, a multi-station welding and forming device for automotive C-pillar inner panel assemblies is urgently needed to address these issues. Summary of the Invention

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

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a multi-station welding and forming device for an automobile C-pillar inner panel assembly, comprising: a welding point grouping and path optimization module for grouping input welding point data information and calculating and outputting optimal welding path coordinate data;

[0007] A PLC system and a Profibus-DP communication bus, wherein the PLC system is used to receive the optimal welding path coordinate data, calculate it, and temporarily store it internally, and when called, output welding instructions through the Profibus-DP communication bus;

[0008] A welding module, configured to respond to the welding instruction and perform welding operations;

[0009] A feeding module, a piezoelectric ceramic sensor and an industrial computer, wherein the feeding module includes a feeding fixture;

[0010] The feeding module is used to automatically feed the C-pillar inner panel assembly, the piezoelectric ceramic sensor is used to detect the clamping pressure data of each clamping area of the feeding fixture, and the industrial computer is used to receive the clamping pressure data and transmit it to the PLC system via the Modbus TCP protocol.

[0011] In which, the welding module is arranged in the middle of the feeding module. During the welding action performed by the welding module, when the clamping pressure data exceeds the rated threshold, the PLC system is triggered to send instructions to the feeding fixture through the Profibus-DP communication bus, and dynamically adjust the clamping pressure of the corresponding clamping area of the C-pillar inner panel assembly in the feeding fixture.

[0012] As a further preferred embodiment of the present technical solution: the welding point grouping and path optimization module includes a welding point information input unit, a welding point grouping unit, a welding path optimization algorithm and an optimal path output unit;

[0013] The welding point information input unit is used to receive the welding point data of the entire C-pillar inner panel and transmit the welding point data to the welding point grouping unit for grouping. The welding point data is n welding points on the entire C-pillar inner panel. The welding module is equipped with m welding robots ;

[0014] Among them, n solder joints In the process, some welding points that need to be welded symmetrically to reduce the longitudinal displacement of the weldment are pre-set as a group;

[0015] Among them, n solder joints In the case of a small area with multiple solder joints, the solder joints that need to be staggered are pre-set into a group;

[0016] The grouping mathematical model in the solder joint grouping unit is:

[0017] (1)

[0018] Solder point grouping constraints:

[0019] (2)

[0020] (3)

[0021] (4)

[0022] in, is the optimal welding point allocation result of multiple welding robots in this welding assembly forming device. For solder joints Distance-distributed welding robots distance, Indicates welding robot Spatial range of welding work area, Indicates the maximum radius of the welding work area. It represents the minimum radius of the welding work area. Formula (1) indicates the shortest distance between the welding spot and the welding robot. Formulas (2) and (3) indicate that a single welding spot is assigned to only one robot. Formula (4) indicates the upper and lower limits of the number of welding spots assigned to each robot.

[0023] As a further preferred embodiment of the present technical solution: the welding path optimization algorithm is used to receive the n welding point grouping result data output by the welding point grouping unit and construct a path optimization objective function with the shortest robot welding path as the goal, and then output the shortest global welding path parameters after logical operation;

[0024] The path optimization objective function is:

[0025] (5)

[0026] In formula (5), represents the shortest global welding path, Indicates two adjacent welding points and The distance between Indicates the distance between the first solder point and the last solder point.

[0027] As a further preferred embodiment of the present 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;

[0028] Among them, the PLC system includes a power module, a CPU module, an IO signal module, a storage module and a communication module. The power 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 for temporary storage of welding instruction data after calculation by the CPU module. When the welding instruction data is called by the CPU, the PLC system sends the welding instruction to the welding module through the Profibus-DP communication bus.

[0029] As a further preferred embodiment of the present technical solution: the welding module includes a first welding robot and a second welding robot, the first welding robot is provided with a first welding gun, and the second welding robot is provided with a second welding gun;

[0030] The first welding robot is used to receive the welding instruction logic calculation and then send a driving instruction to the motor to adjust the rotation angle posture and movement trajectory;

[0031] The first welding robot is also used to receive the welding instruction and perform logical calculations, and then send a welding instruction to the first welding gun to output welding voltage and welding current so that the first welding gun can perform the welding task on the entire body of the C-pillar inner panel.

[0032] As a further preferred embodiment of the present technical solution: the second welding robot is configured to receive the welding instruction and perform logical calculations thereafter, and then send a driving instruction to the motor to adjust the rotation angle, posture and movement trajectory;

[0033] The second welding robot is further configured to receive the welding instruction, perform logical calculations, and then send a welding instruction to the second welding gun to output welding voltage and welding current so that the second welding gun can perform the welding task on the entire C-pillar inner panel.

[0034] As a further preferred embodiment of the present technical solution: the storage module in the PLC system also stores feeding program data, the CPU module is used to call the feeding program data for logical operation and then send feeding instructions to the feeding module through the Profibus-DP communication bus, and the feeding module is used to receive the feeding instructions and then perform feeding, feeding and clamping actions.

[0035] As a further preferred embodiment of the present technical solution: the feeding module includes a first feeding production line and a second feeding production line, the first feeding production line is provided with a first feeding fixture, and the second feeding production line is provided with a second feeding fixture;

[0036] The first feeding production line and the second feeding production line receive the feeding instruction to execute automatic feeding actions of the production lines.

[0037] As a further preferred embodiment of the present technical solution: the feeding module further includes a first feeding robot and a second feeding robot;

[0038] The first feeding robot and the second feeding robot are used to perform feeding and handling functions on the C-pillar inner panel assembly after receiving the feeding instruction;

[0039] The feeding fixture is used to receive the feeding instruction and then perform the clamping function on the C-pillar inner panel assembly;

[0040] The first feeding robot and the second feeding robot are both arranged between the first loading production line and the second loading production line, and the feeding fixture is arranged between the first feeding robot and the second feeding robot;

[0041] The feeding fixture is also disposed between the first welding robot and the second welding robot.

[0042] As a further preferred embodiment of the present technical solution: the piezoelectric ceramic sensor is arranged on the feeding fixture, and a plurality of groups of the piezoelectric ceramic sensors are provided.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The weld point grouping and path optimization module developed based on the Matlab platform in the present invention first groups the weld point information data of the imported C-pillar inner panel. Continuous weld points are staggered and grouped, some weld points are symmetrically grouped, and weld points without obvious geometric distribution characteristics and process requirements are independently grouped. The grouped data output by the weld point grouping unit not only solves the problem of uneven residual stress distribution during welding, but also solves the problem of thermal field imbalance through the symmetrical grouping jump welding method. This achieves the technical effect of optimal weld point distribution for the entire C-pillar inner panel, effectively improving welding quality.

[0045] 2. The welding path optimization algorithm in the weld point grouping and path optimization module of the present invention receives the weld point grouping parameters output by 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 and second welding robots respond to the welding instructions to achieve the coordinated welding function of the two robots. Because the welding path optimization algorithm constructs the shortest global welding path, it improves welding efficiency and production cycle time.

[0046] 3. Each clamping area of the feed fixture in the present invention is provided with a piezoelectric ceramic sensor, which is used to detect the clamping pressure data of each clamping area of the feed fixture. The industrial computer is used to receive the clamping pressure data and transmit it to the PLC system via the Modbus TCP protocol. During the welding process, when the clamping pressure data exceeds the rated threshold, the PLC system is triggered to send a command to the feed fixture via the Profibus-DP communication bus, thereby dynamically adjusting the clamping pressure of the corresponding clamping area of the C-pillar inner panel in the feed fixture to compensate for thermal deformation displacement, suppress local stress changes during welding, and thus suppress deformation;

[0047] 4. In the present invention, the feeding module receives the timing control instructions sent by the PLC system through the Profibus-DP communication bus, controls the orderly operation of the entire system, and ensures that the first feeding production line drives the first feeding fixture to advance a preset number of steps, and then the first feeding robot clamps the C-pillar inner panel assembly in the first feeding fixture and turns it to the feeding fixture and places it. After the feeding fixture clamps the C-pillar inner panel assembly, it provides welding conditions for the welding module. The PLC system executes the welding instruction after receiving the pressure signal from the piezoelectric ceramic sensor, and the second feeding production line also executes the timing control instruction. The two production lines feed in sequence, which ensures feeding efficiency and quality and improves the welding rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a schematic diagram of the three-dimensional structure of a multi-station welding and forming device for an automobile C-pillar inner panel assembly according to the present invention;

[0049] Figure 2 for Figure 1 Schematic diagram of the enlarged structure at A in the middle;

[0050] Figure 3 for Figure 1 Schematic diagram of the enlarged structure at B in the middle;

[0051] Figure 4 This is a schematic diagram of the operating structure of a multi-station welding and forming device for an automobile C-pillar inner panel assembly according to the present invention;

[0052] Figure 5 This is a flowchart of the operation of the welding point grouping and path optimization module in the multi-station welding forming device for the inner panel assembly of the automobile C-pillar of the present invention;

[0053] Figure 6 This is a flow chart of the operation of a welding path optimization algorithm in a multi-station welding forming device for an automobile C-pillar inner panel assembly according to the present invention;

[0054] Figure 7 This is a schematic diagram of the module structure of a PLC system in a multi-station welding and forming device for an automobile C-pillar inner panel assembly according to the present invention;

[0055] Figure 8 This is a flowchart of the multi-station welding and forming apparatus for an automotive C-pillar inner panel assembly according to the present invention. In the diagram: 10, first feeding robot; 20, second feeding robot; 30, first welding robot; 301, first welding gun; 40, second welding robot; 401, second welding gun; 50, first loading line; 501, first loading fixture; 60, second loading line; 601, second loading fixture; 70, feeding fixture; 80, piezoelectric ceramic sensor; 90, C-pillar inner panel assembly. DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0057] In the description of the present invention, it should be understood that terms such as "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0058] Example

[0059] In order to solve the problems that the existing welding devices mostly use fixed welding paths without considering the grouping of welding points and the balance of thermal fields, resulting in uneven residual stress distribution and local sheet metal deformation; and the traditional fixtures use uniform clamping force, which cannot dynamically suppress the local stress changes during welding, resulting in constraint failure, a multi-station welding forming device for the inner panel assembly of the automobile C-pillar is designed in the embodiment of the present application. Figure 1-Figure 7 As shown, it includes: a welding point grouping and path optimization module, which is used to group the input welding point data information and calculate and output the optimal welding path coordinate data;

[0060] The weld point grouping and path optimization module developed based on the Matlab platform first groups the weld point information data of the imported C-pillar inner panel total body 90. Among them, continuous weld points are staggered and grouped, some weld points are symmetrically grouped, and welds without obvious geometric distribution characteristics and process requirements are grouped independently. The grouped data output by the weld point grouping unit not only solves the problem of uneven residual stress distribution during welding, but also solves the problem of thermal field imbalance through the symmetrical grouping jump welding method, thereby achieving the technical effect of optimal distribution of weld points for the total body 90 of the C-pillar inner panel, effectively improving the welding quality.

[0061] like Figure 4 As shown, the PLC system and the Profibus-DP communication bus, the PLC system is used to receive the optimal welding path coordinate data and temporarily store it internally after calculation, and output the welding instruction through the Profibus-DP communication bus when called;

[0062] like Figure 4 As shown, the welding module is used to respond to welding instructions and perform welding actions;

[0063] like Figure 4As shown, the feeding module, the piezoelectric ceramic sensor and the industrial computer are provided, and the feeding module includes a feeding fixture 70;

[0064] like Figure 4 and Figure 3 As shown, the feeding module is used to automatically feed and load the C-pillar inner panel assembly 90, 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 computer is used to receive the clamping pressure data and transmit it to the PLC system via the Modbus TCP protocol;

[0065] like Figure 1 、 Figure 2 as well as Figure 4 As shown, the welding module is arranged in the middle of the feeding module. During the welding operation performed by the welding module, when the clamping pressure data exceeds the rated threshold, the PLC system is triggered to send instructions to the feeding fixture 70 through the Profibus-DP communication bus, and dynamically adjust the clamping pressure of the corresponding clamping area of the C-pillar inner panel total body 90 in the feeding fixture 70.

[0066] In this embodiment, Figure 5 As shown, the solder point grouping and path optimization module includes a solder point information input unit, a solder point grouping unit, a solder path optimization algorithm, and an optimal path output unit;

[0067] The welding point information input unit is used to receive the welding point data of the C-pillar inner panel total body 90 and transmit the welding point data to the welding point grouping unit for grouping. The welding point data is n welding points on the C-pillar inner panel total body 90. , there are m welding robots in the welding module ;

[0068] Among them, n solder joints In the process, some welding points that need to be welded symmetrically to reduce the longitudinal displacement of the weldment are pre-set as a group;

[0069] Among them, n solder joints In the case of a small area with multiple solder joints, the solder joints that need to be staggered are pre-set into a group;

[0070] The mathematical model of grouping in the solder joint grouping unit is:

[0071] (1)

[0072] Solder point grouping constraints:

[0073] (2)

[0074] (3)

[0075] (4)

[0076] in, is the optimal welding point allocation result of multiple welding robots in this welding assembly forming device. For solder joints Distance-distributed welding robots distance, Indicates welding robot Spatial range of welding work area, Indicates the maximum radius of the welding work area. It represents the minimum radius of the welding work area. Formula (1) indicates the shortest distance between the welding spot and the welding robot. Formulas (2) and (3) indicate that a single welding spot is assigned to only one robot. Formula (4) indicates the upper and lower limits of the number of welding spots assigned to each robot.

[0077] In this embodiment, Figure 6 As shown, the welding path optimization algorithm is used to receive the n welding point grouping result data output by the welding point grouping unit and construct the path optimization objective function with the shortest robot welding path as the goal, and then output the shortest global welding path parameters after logical operation;

[0078] The path optimization objective function is:

[0079] (5)

[0080] In formula (5), represents the shortest global welding path, Indicates two adjacent welding points and The distance between Indicates the distance between the first solder point and the last solder point.

[0081] Among them, such as Figure 6 As shown in Figure 2, the welding path optimization algorithm includes the following steps:

[0082] A1, receives the solder joint parameters output from the solder joint grouping unit and initializes the algorithm;

[0083] A2, based on process requirements, to suppress deformation and displacement, construct a local welding path;

[0084] A3, after the local welding path is constructed, the local pheromone is updated, otherwise the local welding path is reconstructed;

[0085] A4, after the local pheromone update is completed, the global pheromone update is realized;

[0086] A5, after the global pheromone is updated, the shortest global welding path is finally constructed and output.

[0087] The welding path optimization algorithm in the welding point grouping and path optimization module receives the welding point 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 30 and the second welding robot 40 respond to the welding instructions to realize the coordinated welding function of the dual robots. Since the welding path optimization algorithm constructs the shortest global welding path, it improves welding efficiency and production rhythm.

[0088] like Figure 5 As 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;

[0089] Among them, such as Figure 4 and Figure 7 As shown, the PLC system includes a power module, a CPU module, an IO signal module, a storage module and a communication module. The power 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 for temporary storage of welding instruction data after calculation by the CPU module. When the welding instruction data is called by the CPU, the PLC system sends the welding instruction to the welding module through the Profibus-DP communication bus.

[0090] In this embodiment, Figure 1 、 Figure 2 and Figure 4 As shown, the welding module includes a first welding robot 30 and a second welding robot 40 . The first welding robot 30 is provided with a first welding gun 301 , and the second welding robot 40 is provided with a second welding gun 401 .

[0091] The first welding robot 30 is used to receive the welding instruction logic calculation and then send the driving instruction to the motor to adjust the rotation angle posture and movement trajectory;

[0092] The first welding robot 30 is also used to receive welding instructions, perform logical calculations, and send welding instructions to the first welding gun 301 to output welding voltage and welding current so that the first welding gun 301 can perform the welding task on the C-pillar inner panel assembly 90.

[0093] The second welding robot 40 is used to receive the welding instruction logic calculation and send the driving instruction to the motor to adjust the rotation angle posture and movement trajectory;

[0094] Among them, such as Figure 1 and Figure 2As shown, the second welding robot 40 is also used to receive welding instructions, perform logical calculations, and send welding instructions to the second welding gun 401 to output welding voltage and welding current so that the second welding gun 401 can perform the welding task on the C-pillar inner panel assembly 90.

[0095] like Figure 4 and Figure 7 As 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 logical operation and then send the feeding instruction to the feeding module through the Profibus-DP communication bus. The feeding module is used to receive the feeding instruction and then perform the loading, feeding and clamping actions.

[0096] A multi-station welding and forming device for an automobile C-pillar inner panel assembly in an embodiment of the present application can be used in the process of automobile sheet metal welding. Specifically, the automobile sheet metal is not limited to the C-pillar inner panel assembly body 90, the front longitudinal beam assembly, the A-pillar inner panel assembly body, etc.

[0097] In this embodiment, Figure 1 and Figure 3 As shown, the feeding module includes a first feeding production line 50 and a second feeding production line 60. The first feeding production line 50 is provided with a first feeding fixture 501, and the second feeding production line 60 is provided with a second feeding fixture 601;

[0098] Each clamping area of the feeding fixture 70 is provided with a piezoelectric ceramic sensor 80, which is used to detect the clamping pressure data of each clamping area of the feeding fixture 70. The industrial computer is used to receive the clamping pressure data and transmit it to the PLC system via the Modbus TCP protocol. During the welding process, when the strain pressure data exceeds the rated threshold, the PLC system is triggered to send a command to the feeding fixture 70 via the Profibus-DP communication bus, thereby dynamically adjusting the clamping pressure of the corresponding clamping area of the feeding fixture 70 on the C-pillar inner panel body 90 to compensate for thermal deformation displacement, suppress local stress changes during welding, and thus suppress deformation;

[0099] The first loading production line 50 and the second loading production line 60 receive the loading instructions and execute the automatic loading action of the production line.

[0100] In this embodiment, Figure 1 、 Figure 2 and Figure 3 As shown, the feeding module further includes a first feeding robot 10 and a second feeding robot 20;

[0101] The first feeding robot 10 and the second feeding robot 20 are used to perform feeding and handling functions on the C-pillar inner panel assembly 90 after receiving the feeding instruction;

[0102] Among them, such as Figure 2 As shown, the feeding fixture 70 is used to perform the clamping function of the C-pillar inner panel assembly 90 after receiving the feeding instruction;

[0103] like Figure 1 and Figure 2 As shown, the first feeding robot 10 and the second feeding robot 20 are both arranged between the first loading production line 50 and the second loading production line 60, and the feeding fixture 70 is arranged between the first feeding robot 10 and the second feeding robot 20;

[0104] Among them, the feeding module receives the timing control instructions sent by the PLC system through the Profibus-DP communication bus, controls the orderly operation of the entire system, and ensures that the first feeding production line 50 drives the first feeding fixture 501 to move forward a preset number of steps, and then the first feeding robot 10 clamps the C-pillar inner panel assembly body 90 in the first feeding fixture 501 and turns it to the feeding fixture 70 and places it. After the feeding fixture 70 clamps the C-pillar inner panel assembly body 90, it provides welding conditions for the welding module. After receiving the pressure signal from the piezoelectric ceramic sensor 80, the PLC system executes the welding instruction, and the second feeding production line 60 also executes the timing control instruction. The two production lines feed in sequence, which ensures the feeding efficiency and quality and improves the welding rate.

[0105] like Figure 1 and Figure 2 As shown, the feeding fixture 70 is also disposed between the first welding robot 30 and the second welding robot 40 .

[0106] In this embodiment, Figure 2 As shown, the piezoelectric ceramic sensors 80 are disposed on the feeding fixture 70 , and a plurality of piezoelectric ceramic sensors 80 are provided.

[0107] 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 , a specific embodiment is described in detail below:

[0108] During the first run, welding parameters and material feeding parameters are pre-set on the PLC system, and the weld point information data on the C-pillar inner panel assembly 90 is imported into the Matlab platform. The weld point grouping and path optimization module developed on the Matlab platform receives the weld point information data and outputs weld point path coordinate data after performing logical operations. The PLC system responds to the weld point path coordinate data from the weld point grouping and path optimization module, and after calculation by the CPU module, outputs welding instructions that are temporarily stored in the storage module within the PLC system.

[0109] Secondly, the CPU module in the PLC system calls the feeding program data on the storage module for calculation and sends the 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 to advance a preset number of steps, and then the first feeding robot 10 clamps the C-pillar inner panel total body 90 in the first feeding fixture 501 and turns it to the feeding fixture 70 and places it. Similarly, the second feeding production line 60 drives the second feeding fixture 601 to advance a preset number of steps, and then the second feeding robot 20 clamps the C-pillar inner panel total body 90 in the second feeding fixture 601 and turns it to the feeding fixture 70 and places it.

[0110] Then, the feeding fixture 70 responds to the feeding instruction sent from the PLC system via the Profibus-DP communication bus, and clamps the C-pillar inner panel assembly 90 with uniform pressure in each clamping area. Since each clamping area of the feeding fixture 70 is provided with a piezoelectric ceramic sensor 80, after the piezoelectric ceramic sensor 80 obtains the clamping pressure value of each clamping area of the feeding fixture 70, the industrial computer receives the pressure signal of the piezoelectric ceramic sensor 80 and transmits it to the PLC system via the Modbus TCP protocol. After the PLC system responds to the pressure signal of the piezoelectric ceramic sensor 80, the welding conditions are ready, and the PLC system calls the welding instruction on the storage module through the CPU module.

[0111] Finally, the first welding robot 30 receives the welding instruction, calculates and drives the adjustment posture, and controls the welding voltage and welding current output by the first welding gun 301 to perform the welding task of the C-pillar inner panel body 90. The second welding robot 40 receives the welding instruction, calculates and drives the adjustment posture, and controls the welding voltage and welding current output by the second welding gun 401 to perform the welding task of the C-pillar inner panel body 90.

[0112] During the welding process, when the pressure data of individual clamping areas obtained by the piezoelectric ceramic sensor 80 exceeds the rated threshold, the PLC system is triggered to send instructions to the feeding fixture 70 through the Profibus-DP communication bus to increase the clamping pressure of the corresponding clamping area, and then dynamically adjust the corresponding clamping force of the feeding fixture 70 on the total body 90 of the C-pillar inner panel, thereby compensating for thermal deformation displacement and suppressing deformation.

[0113] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A multi-station welding and forming device for an automobile C-pillar inner panel assembly, characterized in that: include: The welding point grouping and path optimization module is used to group the input welding point data information and calculate and output the optimal welding path coordinate data; A PLC system and a Profibus-DP communication bus, wherein the PLC system is used to receive the optimal welding path coordinate data, calculate it, and temporarily store it internally, and when called, output welding instructions through the Profibus-DP communication bus; A welding module, configured to respond to the welding instruction and perform welding operations; A feeding module, a piezoelectric ceramic sensor and an industrial computer, wherein the feeding module includes a feeding fixture; The feeding module is used to automatically feed the C-pillar inner panel assembly, the piezoelectric ceramic sensor is used to detect the clamping pressure data of each clamping area of the feeding fixture, and the industrial computer is used to receive the clamping pressure data and transmit it to the PLC system via the Modbus TCP protocol. The welding module is arranged in the middle of the feeding module. When the clamping pressure data exceeds the rated threshold value during the welding operation of the welding module, the PLC system is triggered to send instructions to the feeding fixture via the Profibus-DP communication bus to dynamically adjust the clamping pressure of the corresponding clamping area of the C-pillar inner panel assembly in the feeding fixture. The welding point grouping and path optimization module includes a welding point information input unit, a welding point grouping unit, a welding path optimization algorithm and an optimal path output unit; The welding point information input unit is used to receive the welding point data of the entire C-pillar inner panel and transmit the welding point data to the welding point grouping unit for grouping. The welding point data is n welding points on the entire C-pillar inner panel. The welding module is equipped with m welding robots ; Among them, n solder joints In the process, some welding points that need to be welded symmetrically to reduce the longitudinal displacement of the weldment are pre-set as a group; Among them, n solder joints In the case of a small area with multiple solder joints, the solder joints that need to be staggered are pre-set into a group; The grouping mathematical model in the solder joint grouping unit is: （1） Solder point grouping constraints: （2） （3） （4） in, is the optimal welding point allocation result of multiple welding robots in this welding assembly forming device. For solder joints Distance-distributed welding robots distance, Indicates welding robot Spatial range of welding work area, Indicates the maximum radius of the welding work area. It represents the minimum radius of the welding work area. Formula (1) represents the shortest distance between the welding spot and the welding robot. Formulas (2) and (3) represent that a single welding spot is assigned to only one robot. Formula (4) represents the upper and lower limits of the number of welding spots assigned to each robot. The welding path optimization algorithm is used to receive the n welding point grouping result data output by the welding point grouping unit and construct a path optimization objective function with the shortest robot welding path as the goal, and then output the shortest global welding path parameters after logical operation; The path optimization objective function is: （5） In formula (5), represents the shortest global welding path, Indicates two adjacent welding points and The distance between Indicates the distance between the first solder point and the last solder point.

2. The multi-station welding and forming device for the automobile C-pillar inner panel assembly according to claim 1 is characterized in that: 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 module, a CPU module, an IO signal module, a storage module and a communication module. The power 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 for temporary storage of welding instruction data after calculation by the CPU module. When the welding instruction data is called by the CPU, the PLC system sends the welding instruction to the welding module through the Profibus-DP communication bus.

3. The multi-station welding and forming device for the automobile C-pillar inner panel assembly according to claim 2 is characterized in that: The welding module includes a first welding robot and a second welding robot, the first welding robot is provided with a first welding gun, and the second welding robot is provided with a second welding gun; The first welding robot is used to receive the welding instruction logic calculation and then send a driving instruction to the motor to adjust the rotation angle posture and movement trajectory; The first welding robot is also used to receive the welding instruction and perform logical calculations, and then send a welding instruction to the first welding gun to output welding voltage and welding current so that the first welding gun can perform the welding task on the entire body of the C-pillar inner panel.

4. The multi-station welding and forming device for the automobile C-pillar inner panel assembly according to claim 3 is characterized in that: The second welding robot is used to receive the welding instruction and perform logical calculations, and then send a driving instruction to the motor to adjust the rotation angle posture and movement trajectory; The second welding robot is further configured to receive the welding instruction, perform logical calculations, and then send a welding instruction to the second welding gun to output welding voltage and welding current so that the second welding gun can perform the welding task on the entire C-pillar inner panel.

5. The multi-station welding and forming device for the automobile C-pillar inner panel assembly according to claim 4 is characterized in that: The storage module in the PLC system also stores feeding program data. The CPU module is used to call the feeding program data for logical operation and then send feeding instructions to the feeding module through the Profibus-DP communication bus. The feeding module is used to receive the feeding instructions and then perform feeding, feeding and clamping actions.

6. The multi-station welding and forming device for the automobile C-pillar inner panel assembly according to claim 5 is characterized in that: The feeding module includes a first feeding production line and a second feeding production line, the first feeding production line is provided with a first feeding fixture, and the second feeding production line is provided with a second feeding fixture; The first feeding production line and the second feeding production line receive the feeding instruction to execute the automatic feeding action of the production line.

7. The multi-station welding and forming device for the automobile C-pillar inner panel assembly according to claim 6 is characterized in that: The feeding module further includes a first feeding robot and a second feeding robot; The first feeding robot and the second feeding robot are used to perform feeding and handling functions on the C-pillar inner panel assembly after receiving the feeding instruction; The feeding fixture is used to receive the feeding instruction and then perform the clamping function on the C-pillar inner panel assembly; The first feeding robot and the second feeding robot are both arranged between the first loading production line and the second loading production line, and the feeding fixture is arranged between the first feeding robot and the second feeding robot; The feeding fixture is also disposed between the first welding robot and the second welding robot.

8. The multi-station welding and forming device for the automobile C-pillar inner panel assembly according to claim 7 is characterized in that: The piezoelectric ceramic sensors are arranged on the feeding fixture, and a plurality of groups of the piezoelectric ceramic sensors are provided.

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