Self-adaptive shape follow-up clamping device for welding automobile seat framework

Abstract

The invention discloses a self-adaptive shape follow-up clamping device for welding of an automobile seat framework, and relates to the technical field of welding fixtures, the self-adaptive shape follow-up clamping device comprises a clamping mechanism of a three-jaw structure, and the contact claw clamping mechanism is arranged at the side end of the driving mechanism. A fine adjustment ball array is arranged in a flexible contact bag assembly, in the initial clamping stage, a workpiece is allowed to move passively so as to eliminate positioning deviation, and meanwhile a coating is prevented from being scratched; the pressure of each point is monitored in real time in combination with a bottom distributed pressure sensor, a built-in logic controller drives a side auxiliary adjusting mechanism to carry out macroscopic attitude compensation, micron-scale pushing is carried out on a local contact bag through a micro control columnar air bag, it is ensured that the pressure of all the contact points is uniform, and the contact points are completely attached to the curved surface of a workpiece; and in the process, the thermal stress is continuously adjusted and released, the method effectively adapts to a complex curved surface, and the welding precision is improved.

Description

Technical Field

[0001] This invention relates to the field of welding fixture technology, specifically to an adaptive conformal clamping device for welding automotive seat frames. Background Technology

[0002] Automotive seat frames are typically welded from various specifications of thin-walled tubular components and stamped parts. Their structure is complex, with varied curvatures, and requires high welding precision and appearance quality. During the welding process, the clamping and positioning of the workpiece is a crucial step in ensuring weld quality.

[0003] Currently, there are two main methods for welding and clamping automotive seat frames: one is the traditional rigid mechanical clamp, which clamps the workpiece using fixed positioning blocks and a clamping mechanism. The disadvantages of this method are: since seat frames are mostly thin-walled parts, rigid clamps are prone to causing localized indentations or deformation; and they are difficult to adapt to the complex curved shapes of the frame, often resulting in clamping blind spots, leading to workpiece vibration or displacement during welding, affecting welding accuracy. The other method uses vacuum adsorption or electromagnetic adsorption clamps, but vacuum adsorption requires a high degree of workpiece surface cleanliness and cannot withstand high-temperature welding environments; electromagnetic adsorption is only suitable for ferromagnetic materials, and the clamping force distribution is uneven, also resulting in clamping deformation.

[0004] Currently, some flexible clamping technologies using magnetorheological fluids also exist, which control the solidification and liquefaction of the magnetorheological fluid through a magnetic field to achieve adaptive clamping of the workpiece. However, existing technologies mostly employ a single bag structure or piston array structure, which cannot achieve precise control of microscopic contact forces. This results in limited fit to complex curved surfaces and a lack of effective mechanisms to cope with welding thermal stress. Consequently, the deformation of the workpiece caused by thermal expansion during welding cannot be released, leading to large residual stress after welding. Furthermore, it cannot eliminate positioning deviations from the previous process, requiring high precision in the preceding processes. At the same time, the clamping posture adjustment capability is limited, making it difficult to adapt to the multi-angle welding requirements of the skeleton. Summary of the Invention

[0005] The purpose of this invention is to provide an adaptive conformal clamping device for welding automotive seat frames, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an adaptive conformal clamping device for welding automotive seat frames, comprising a clamping mechanism configured with a three-jaw structure, wherein one jaw of the clamping mechanism includes: Drive mechanism; A contact claw clamping mechanism is installed on the side of the drive mechanism, and its interior is provided with a main cavity for containing magnetorheological fluid. The side adjustment mechanism is located at the bottom of the drive mechanism and is used to cooperate with the contact claw clamping mechanism to clamp the workpiece. A flexible contact bladder assembly is embedded in the clamping working surface of a contact claw mechanism. The flexible contact bladder assembly includes multiple independent flexible contact bladders. The top of the inner cavity of each flexible contact bladder is sequentially connected to a miniature one-way check valve, a magnetorheological fluid secondary chamber, and an independent channel. The independent channel is connected to the main cavity. A fine-tuning ball array is embedded in the clamping working surface of each flexible contact bladder. The fine-tuning ball array includes multiple independently arranged miniature balls. The spherical surface of the miniature balls is slightly higher than the surface of the flexible contact bladder for contacting the workpiece. A distributed pressure sensor is installed at the bottom of each flexible contact bladder for real-time monitoring of the clamping pressure at the corresponding contact point and generating a pressure signal. The contact claw gripper mechanism includes: The main electromagnet matrix is ​​fixed at the bottom of the main cavity and is correspondingly set with multiple independent flexible contact bladders. It is used to generate a magnetic field when energized to drive the magnetorheological fluid in the main cavity to flow into the corresponding flexible contact bladder and solidify it.

[0007] Preferably, the contact claw gripping mechanism further includes: The built-in logic controller is electrically connected to the main electromagnet matrix and the distributed pressure sensors respectively, and is used to receive pressure signals and independently control the energizing state of each main electromagnet. A drive rod, which is connected to the actuating end of the drive mechanism; The top surface of the slotted frame is provided with a slot to allow space for the drive rod to move, and the side wall surface of the slotted frame is provided with an arc groove. The multi-hinged rod has its side end connected to the fixed frame at the bottom of the drive mechanism, and its other end is rotatably connected via a rotating shaft and an arc groove.

[0008] Preferably, the contact claw clamping mechanism further includes: The main electromagnet mounting contact seat is hinged to the side end of the drive rod and is used to mount the main electromagnet. A central drive rod frame is hinged to a slot frame, and an end drive rod frame is hinged to the side end of the central drive rod frame. The bottoms of the drive rod, the central drive rod frame, and the end drive rod frame are respectively connected to the main electromagnet mounting contact seat.

[0009] Preferably, the flexible contact pouch assembly further includes: The mounting cavity is embedded in the bottom surface of the main electromagnet mounting contact seat; The mounting plate, which is coaxially positioned at the bottom of the mounting cavity, is used to limit the fine-tuning ball array and the distributed pressure sensor; The sliding plate is integrated with the installation plate. An outer sliding frame is installed at the bottom of the mounting cavity. The connection end between the outer sliding frame and the sliding disk has an installation space. An annular air guide is installed inside the mounting space. A miniature control columnar airbag is arranged around the annular air guide. The miniature control columnar airbag and the sliding edge of the sliding disk are correspondingly arranged.

[0010] Preferably, the flexible contact bladder assembly further includes: An air pipe, which is embedded in the body of the mounting cavity, is used to connect to an external air pump. A miniature solenoid valve is installed on the side end of the air pipe. An auxiliary excitation coil is fitted outside the magnetorheological fluid secondary chamber and electrically connected to the built-in logic controller. It is used to energize the clamping mechanism before it comes into contact with the workpiece to generate a magnetic field to lock the magnetorheological fluid in the magnetorheological fluid secondary chamber and prevent it from flowing into the flexible contact bag. The magnetorheological fluid distributor is installed at the bottom of the miniature one-way check valve and is located inside the flexible contact bladder.

[0011] Preferably, each of the micro-balls has an independent damping cavity below it. The independent damping cavity is connected to the annular directional pipe at the bottom of the micro one-way check valve. The independent damping cavity is isolated from the inner cavity of the flexible contact bladder and filled with magnetorheological fluid. The bottom of the micro-ball is immersed in the magnetorheological fluid in the independent damping cavity. A secondary micro excitation coil is arranged around each of the independent damping cavities. The secondary micro excitation coil is electrically connected to the built-in logic controller for independently controlling the rotational damping force of the micro-ball.

[0012] Preferably, the drive mechanism includes: Drive components; A gear set, which is connected to the output end of the drive component; A threaded rod that connects to the top gear in a gear set; An external drive threaded sleeve is connected to the external thread of a drive threaded rod, and the side end of the external drive threaded sleeve is hinged to the drive rod.

[0013] Preferably, the side adjustment mechanism includes: The mounting section is connected to the side end and multiple hinged rods; A rotating shaft is rotatably mounted inside an installation section. A first half-ring gear is sleeved on the outer side of the rotating shaft, and a first gear drive component is meshed with the side end of the first half-ring gear. A rotating shaft column is rotatably connected to the bottom end of a rotating shaft. A second half-ring gear is sleeved on the outside of the rotating shaft in the rotating shaft column, and a second gear drive component is meshed at the bottom end of the second half-ring gear. The first contact element has a second contact element rotatably connected to its bottom end; A connecting member is connected to the bottom of the rotating shaft column, which is used to connect the first contact member and the second contact member.

[0014] Preferably, the built-in logic controller is used to control the auxiliary excitation coil and the secondary micro excitation coil to be energized before the clamping mechanism contacts the workpiece, so as to keep all flexible contact bladders in a soft and collapsed state. After the clamping mechanism is fully attached to the workpiece, according to the preset clamping requirements, the power supply of the auxiliary excitation coil corresponding to the target flexible contact bladder is selectively disconnected, and the corresponding main electromagnet is energized at the same time, so that the magnetorheological fluid flows into and solidifies the target flexible contact bladder first, forming a support surface with the curvature of the workpiece surface.

[0015] Preferably, the built-in logic controller supplies a first current to the secondary micro excitation coil, causing the magnetorheological fluid in the independent damping cavity to completely solidify and lock the micro-ball. The built-in logic controller also supplies a second current, lower than the first current, to the secondary micro excitation coil, causing the magnetorheological fluid in the independent damping cavity to be in a semi-solid state, providing controllable damping for the rotation of the micro-ball, allowing the workpiece to achieve controlled passive displacement under welding thermal stress. The built-in logic controller is signal-connected to the displacement sensor. The built-in logic controller receives feedback signals from the displacement sensor and applies a directional pulse current to the auxiliary excitation coil corresponding to the target micro-ball, causing it to generate an instantaneous driving torque and drive the workpiece to perform micron-level displacement reset.

[0016] Compared with the prior art, the beneficial effects of the present invention are: In this invention, a fine-tuning ball array is incorporated within the flexible contact bladder assembly. This allows for passive workpiece displacement during the initial clamping phase, eliminating positioning deviations and preventing coating scratches. Combined with bottom-distributed pressure sensors that monitor pressure at various points in real time, a built-in logic controller drives a side-assisted adjustment mechanism for macroscopic attitude compensation. Furthermore, a micro-controlled columnar airbag provides micron-level pushing to local contact bladders, ensuring uniform pressure at all contact points and complete fit to the workpiece's curved surface. Once the fit is achieved, the main electromagnet matrix instantly solidifies the magnetorheological fluid, transforming the flexible bladder into a high-rigidity conformal pad. This, along with the secondary excitation coil locking the fine-tuning balls, creates a fully rigid lock from macro to micro, effectively resisting welding stress and suppressing deformation. During welding, the system continuously monitors pressure fluctuations, releasing thermal stress and achieving controlled displacement by adjusting the magnetic field strength or fine-tuning the ball damping, and even actively resetting the workpiece. This effectively solves the problems of traditional clamps being unable to adapt to complex curved surfaces, easily causing clamping damage or inaccurate positioning, and significantly improves the welding accuracy and quality stability of automotive seat frames. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the main body of an adaptive conformal clamping device for welding automotive seat frames according to the present invention; Figure 2 This is a side view of the structure of an adaptive conformal clamping device for welding automotive seat frames according to the present invention. Figure 3 This invention relates to an adaptive conformal clamping device for welding automotive seat frames. Figure 1 A magnified structural diagram at point A; Figure 4 This is a schematic diagram of the drive mechanism and contact claw clamping mechanism in an adaptive conformal clamping device for welding automotive seat frames according to the present invention. Figure 5 This invention relates to an adaptive conformal clamping device for welding automotive seat frames. Figure 1 A magnified structural diagram at point B; Figure 6 This is a schematic diagram of the flexible contact bladder assembly in an adaptive conformal clamping device for welding an automotive seat frame according to the present invention. Figure 7 This is a schematic diagram of the internal cross-sectional structure of the flexible contact bladder assembly in an adaptive conformal clamping device for welding an automotive seat frame according to the present invention. Figure 8 This is a schematic diagram of the separation structure of the flexible contact bladder assembly in an adaptive conformal clamping device for welding an automotive seat frame according to the present invention.

[0018] In the diagram: 100, Drive mechanism; 101, Drive component; 102, Gear set; 103, Transmission threaded rod; 104, External transmission threaded sleeve; 200, Side auxiliary adjustment mechanism; 201, Mounting section; 202, First gear drive component; 203, First half-ring gear; 204, Rotating shaft; 205, First contact component; 206, Rotating shaft column; 207, Second half-ring gear; 208, Second gear drive component; 210, Second contact component; 220, Section connector; 300, Contact claw clamping mechanism; 301, Groove bracket; 302, Multi-hinged rod; 303, Arc groove; 304, Drive rod; 305, Main electromagnet matrix; 306, Main electromagnet mounting. 307. Contact seat; 308. Middle drive rod; 409. End drive rod; 400. Flexible contact bladder assembly; 401. Mounting cavity; 402. Mounting plate; 403. Air passage; 404. Miniature solenoid valve; 405. Flexible contact bladder; 406. Fine-tuning ball array; 407. Distributed pressure sensor; 408. Magnetorheological fluid secondary chamber; 409. Auxiliary excitation coil; 410. Miniature one-way check valve; 411. Magnetorheological fluid distributor; 412. Outer slide rail; 413. Sliding plate; 414. Annular air guide; 415. Miniature control columnar air bladder; 416. Independent channel; 417. Independent damping chamber; 418. Secondary miniature excitation coil. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Reference Figure 1 , Figure 2 and 4 As shown: An adaptive conformal clamping device for welding automotive seat frames includes a clamping mechanism configured with a three-jaw structure. One jaw of the clamping mechanism includes: a drive mechanism 100, which serves as the power source for this individual jaw; a contact jaw clamping mechanism 300, mounted on the side of the drive mechanism 100, which has an internal main cavity for containing magnetorheological fluid. The magnetorheological fluid is a carbonyl iron powder-based magnetorheological fluid, ensuring rapid response while providing sufficient clamping rigidity, suitable for welding thin-walled automotive seat frame components; a side auxiliary adjustment mechanism 200 located at the bottom of the drive mechanism 100, used to cooperate with the contact jaw clamping mechanism 300 to clamp the workpiece, performing minute angle or position compensation to ensure optimal clamping posture; and a flexible contact bladder assembly 400 embedded in the clamping working surface of the contact jaw clamping mechanism 300, comprising multiple independent flexible contact bladders. 405, the top of the inner cavity of each flexible contact bladder 405 is sequentially connected to a miniature one-way check valve 410, a magnetorheological fluid secondary chamber 408, and an independent channel 416. The independent channel 416 is connected to the main cavity. Each flexible contact bladder 405 has a fine-tuning ball array 406 embedded on its clamping working surface. The fine-tuning ball array 406 includes multiple independently arranged miniature balls. The spherical surface of the miniature balls is slightly higher than the surface of the flexible contact bladder 405 for contacting the workpiece. A distributed pressure sensor 407 is installed at the bottom of each flexible contact bladder 405 for real-time monitoring of the clamping pressure at the corresponding contact point and generating a pressure signal. The contact claw clamping mechanism 300 includes: a main electromagnet matrix 305 fixed to the bottom of the main cavity and corresponding to multiple independent flexible contact bladders 405, for generating a magnetic field when energized to drive the magnetorheological fluid in the main cavity to flow into the corresponding flexible contact bladder 405 and solidify it.

[0021] Specifically, the operator or host computer system calls a pre-stored clamping program based on the model of the car seat frame to be welded. The three-jaw clamping mechanism moves to the vicinity of the workpiece under the drive of an external robotic arm or translation mechanism. At this time, the drive mechanism 100 receives an initial displacement command, causing the contact claw clamping mechanism 300 to move closer to the workpiece surface. During this stage, the main electromagnet matrix 305 is de-energized, so the magnetorheological fluid in the main cavity exhibits a well-flowing Newtonian fluid state. Due to the connection of the independent channels 416, the magnetorheological fluid can freely flow into the inner cavity of each flexible contact bladder 405, keeping the flexible contact bladder 405 soft and freely deformable. Simultaneously, the balls of the fine-tuning ball array 406 can rotate freely. Next, the drive mechanism 100 continues to advance until some of the flexible contact bladders 405 first make physical contact with the complex curved surface of the car seat frame. Because the flexible contact bladders 405 are soft at this time, they will passively deform according to the shape of the contacting curved surface, beginning to initially conform to the workpiece surface. The fine-tuning ball array 406 embedded in the contact surface first contacts the workpiece and rolls as the clamping action proceeds. This avoids the fixture from scratching the coating on the workpiece surface and also allows the workpiece to perform minor self-positioning between the jaws, eliminating the positioning deviation caused by the previous process.

[0022] Simultaneously, the distributed pressure sensors 407 at the bottom of each flexible contact bladder 405 begin to operate in real time, acquiring pressure data at their respective contact points using an extremely high sampling frequency and feeding these real-time pressure signals back to the built-in logic controller. Upon receiving the pressure signals from all the distributed pressure sensors 407, the built-in logic controller immediately analyzes and processes them to determine whether the pressure at each contact point is uniform and whether the total clamping force has reached a preset threshold. For example, if the workpiece surface has a tilt or local bulge, the distributed pressure sensor 407 on the first contacting flexible contact bladder 405 will show a rapid increase in pressure, while the readings of the distributed pressure sensors 407 on other flexible contact bladders 405 that have not yet made effective contact will be close to zero. Based on this uneven pressure distribution, the built-in logic controller sends commands to the drive mechanism 100 and the side auxiliary adjustment mechanism 200. The built-in logic controller can be an STM32F407 series microcontroller, using a PID control algorithm for analysis and control. The drive mechanism 100 slows down or even stops the macroscopic propulsion, while the side-adjustment mechanism 200 starts working. Through slight oscillation or translation, it finely adjusts the clamping angle of the body contact claw mechanism 300, allowing the workpiece surface to contact more of the flexible contact pouches 405, thus gradually equalizing the pressure readings at each point. This facilitates the entire flexible contact pouch assembly 400 contacting the complex curved surfaces of the workpiece, achieving a seamless conformal fit, while ensuring that the pressure at all contact points is controlled within a reasonable range that will neither crush the workpiece (e.g., thin-walled pipes) nor cause clamping instability.

[0023] Once the built-in logic controller confirms through the distributed pressure sensor 407 that the pressure at all contact points has reached the preset equilibrium range and clamping force threshold, it immediately sends an energizing command to the main electromagnet matrix 305. Each main electromagnet in the main electromagnet matrix 305 generates a powerful, controllable magnetic field based on preset logic or feedback from the corresponding distributed pressure sensor 407. This controllable magnetic field acts on the magnetorheological fluid in the main cavity, independent channel 416, magnetorheological fluid secondary chamber 408, and the flexible contact bladder 405. Under the influence of the magnetic field, the rheological properties of the magnetorheological fluid change drastically within milliseconds, transforming from a low-viscosity Newtonian fluid to a high-viscosity, high-yield-stress Bingham fluid—instantly solidifying. This transforms each flexible contact bladder 405 conforming to the workpiece's curved surface into a solid pad with sufficient supporting rigidity, precisely replicating and locking the workpiece's local shape. At this point, even under external welding stress, the clamping state remains extremely stable, and the workpiece will not experience any slight displacement or deformation.

[0024] Subsequently, after the magnetorheological fluid has solidified and the workpiece is firmly and stress-free clamped, the welding robot begins welding the corresponding parts of the seat frame. Throughout the welding process, despite the high temperature and thermal stress generated, the distributed pressure sensor 407 remains continuously operational, monitoring changes in clamping force at each point in real time. If abnormal fluctuations in clamping force due to thermal expansion or stress release are detected, the built-in logic controller can fine-tune the magnetic field strength of the main electromagnet matrix 305, or perform minor force compensation through the side auxiliary adjustment mechanism 200, ensuring optimal clamping conditions are maintained, effectively suppressing welding deformation and guaranteeing welding accuracy.

[0025] Finally, after the welding process is completed, the built-in logic controller first cuts off the current to the main electromagnet matrix 305. With the magnetic field gone, the magnetorheological fluid instantly changes from a solidified state back to a flowing liquid state. Each flexible contact capsule 405 returns to its flexible state. At this time, the drive mechanism 100 reverses its movement, causing the contact claw clamping mechanism 300 to return to its initial position. The flexible contact capsules 405 recover their original shape under the action of their own elasticity and the backflow of the magnetorheological fluid, and the fine-tuning ball array 406 is also ready for the next clamping. The entire device awaits the instruction for the next work cycle.

[0026] Preferred, according to Figure 4 and Figure 5As shown, the contact claw gripping mechanism 300 further includes: a built-in logic controller, which is electrically connected to the main electromagnet matrix 305 and the distributed pressure sensor 407 respectively, for receiving pressure signals and independently controlling the energizing state of each main electromagnet; a drive rod 304 connected to the execution end of the drive mechanism 100; a groove is provided on the top surface of the slot frame 301 to allow the drive rod 304 to move, and an arc groove 303 is provided on the side wall surface of the slot frame 301; the side end of the multi-hinged rod 302 is connected to the fixed frame at the bottom of the drive mechanism 100, and the other end is rotatably connected to the arc groove 303 through a rotating shaft. The contact claw clamping mechanism 300 further includes: a main electromagnet mounting contact seat 306 and a drive rod 304 with the side ends hinged for mounting the main electromagnet; a middle drive rod frame 307 and a slot frame 301 with the middle drive rod frame 307 with an end drive rod frame 308 hinged to the side end; and the bottoms of the drive rod 304, the middle drive rod frame 307 and the end drive rod frame 308 are respectively connected to the main electromagnet mounting contact seat 306.

[0027] Specifically, when the three-jaw gripping mechanism moves to the vicinity of the workpiece under the drive of an external robotic arm or translation mechanism, the drive mechanism 100 receives an initial displacement command, and the drive rod 304 begins to extend. During the advancement of the drive rod 304, the main electromagnet mounting contact seat 306, hinged to it, in cooperation with the hinge mechanism composed of multiple hinged rods 302, a slotted frame 301, and an arc groove 303, drives the entire contact jaw gripping mechanism 300 to smoothly approach the workpiece surface. Simultaneously, the built-in logic controller keeps the main electromagnet matrix 305 in a de-energized state, thus the magnetorheological fluid in the main cavity exhibits a well-flowing Newtonian fluid state. Due to the connection of the independent channels 416, the magnetorheological fluid can freely flow into the inner cavity of each flexible contact capsule 405, keeping the flexible contact capsule 405 soft and freely deformable. At the same time, the balls of the fine-tuning ball array 406 can rotate freely. Next, the drive rod 304 continues to advance, ensuring the synchronous and smooth adjustment of the main electromagnet mounting contact seat 306 through the transmission of the middle drive rod bracket 307 and the end drive rod bracket 308, until some of the flexible contact bladders 405 first make physical contact with the complex curved surface of the car seat frame. Since the flexible contact bladders 405 are soft at this point, they passively deform according to the shape of the contact surface, beginning to initially conform to the workpiece surface. The fine-tuning ball array 406 embedded in the contact surface first contacts the workpiece and rolls as the clamping action proceeds. This avoids the clamp scratching the coating on the workpiece surface and allows the workpiece to perform minor self-positioning between the jaws, eliminating positioning deviations caused by the previous process. Simultaneously, the distributed pressure sensors 407 at the bottom of each flexible contact bladder 405 begin to operate in real time. The built-in logic controller sends commands to the drive mechanism 100 and the side auxiliary adjustment mechanism 200 based on this uneven pressure distribution. The drive mechanism 100 slows down or even stops the macroscopic propulsion, while the side auxiliary adjustment mechanism 200 starts working, fine-tuning the clamping angle of the body contact claw mechanism 300 through slight oscillation or translation, so that more flexible contact pouches 405 can contact the workpiece surface. At the same time, due to the parallel linkage structure formed by the drive rod 304, the middle drive rod frame 307 and the end drive rod frame 308, the contact claw mechanism 300 can always maintain the optimal contact posture during the fine-tuning process.

[0028] Preferred, according to Figures 6-7As shown, the flexible contact bladder assembly 400 further includes: a mounting cavity 401 embedded in the bottom surface of the main electromagnet mounting contact seat 306; a mounting disk 402 coaxially disposed at the bottom of the mounting cavity 401 for limiting the fine-tuning ball array 406 and the distributed pressure sensor 407; a sliding disk 413 and the mounting disk 402 integrated; an outer sliding frame 412 installed at the bottom of the mounting cavity 401, with a mounting space left at the connection end of the outer sliding frame 412 and the sliding disk 413, and an annular air guide 414 installed inside the mounting space, with a miniature control columnar airbag 415 arranged around the periphery of the annular air guide 414, and the sliding edges of the miniature control columnar airbag 415 and the sliding disk 413 correspondingly arranged. The flexible contact bladder assembly 400 also includes: an air pipe 403 embedded in the mounting cavity 401 for connecting to an external air pump, and a miniature solenoid valve 404 installed on the side end of the air pipe 403; an auxiliary excitation coil 409 sleeved outside the magnetorheological fluid secondary chamber 408 and electrically connected to the built-in logic controller for energizing before the clamping mechanism is in contact with the workpiece to generate a magnetic field to lock the magnetorheological fluid in the magnetorheological fluid secondary chamber 408 and prevent it from flowing into the flexible contact bladder 405; and a magnetorheological fluid distributor 411 installed at the bottom of the miniature one-way check valve 410 and located inside the flexible contact bladder 405. Each micro ball has an independent damping cavity 417 located below it. The independent damping cavity 417 is connected to the annular directional pipe at the bottom of the micro one-way check valve 410. The independent damping cavity 417 is isolated from the inner cavity of the flexible contact bladder 405 and filled with magnetorheological fluid. The bottom of the micro ball is immersed in the magnetorheological fluid in the independent damping cavity 417. A secondary micro excitation coil 418 is arranged around each independent damping cavity 417. The secondary micro excitation coil 418 is electrically connected to the built-in logic controller and is used to independently control the rotational damping force of the micro ball.

[0029] Specifically, the three-jaw gripper moves to the vicinity of the workpiece under the drive of an external robotic arm or translation mechanism. At this time, the built-in logic controller issues a command to close the micro solenoid valve 404, depressurizing the annular air guide 414 and the micro control columnar airbag 415; while the auxiliary excitation coil 409 is energized, generating a magnetic field to lock the magnetorheological fluid in the magnetorheological fluid secondary chamber 408, preventing it from flowing into the flexible contact bladder 405. Therefore, the flexible contact bladder 405 remains deflated and contracted, facilitating access to the workpiece without interference; the secondary micro excitation coil 418 is de-energized, the magnetorheological fluid in the independent damping chamber 417 is liquid, and the micro ball bearings can rotate freely. The drive mechanism 100 receives the initial displacement command, and the drive rod 304 begins to extend. During the advancement of the drive rod 304, the main electromagnet mounting contact seat 306 smoothly drives the entire contact claw clamping mechanism 300 toward the workpiece surface through the parallel transmission of the middle drive rod frame 307 and the end drive rod frame 308, in conjunction with the multi-hinged rod 302, the slot frame 301 and the arc groove 303.

[0030] Next, when the contact claw mechanism 300 reaches the predetermined working area, the built-in logic controller issues a new command, causing the auxiliary excitation coil 409 to be de-energized. The magnetorheological fluid in the magnetorheological fluid secondary chamber 408 regains its fluidity. Under the pressure difference or gravity between the main chamber and the magnetorheological fluid secondary chamber 408, the magnetorheological fluid flows evenly into the inner cavity of each flexible contact bladder 405 through the magnetorheological fluid distributor 411, causing it to slowly fill and expand, presenting a soft initial state. At the same time, the drive rod 304 continues to advance until some of the filled flexible contact bladders 405 first make physical contact with the complex curved surface of the car seat frame. The fine-tuning ball array 406 embedded on the contact surface first contacts the workpiece. Since the secondary micro excitation coil 418 is still de-energized at this time, the magnetorheological fluid in the independent damping cavity 417 is liquid and does not dampen the rotation of the micro balls. Therefore, the micro balls can roll extremely sensitively with the clamping action. At the same time, the distributed pressure sensors 407 at the bottom of each flexible contact bladder 405 perform real-time detection and feed these real-time pressure signals back to the built-in logic controller.

[0031] When the drive mechanism 100 drives the contact claw clamping mechanism 300 to advance towards the workpiece surface, the fine-tuning ball array 406 embedded in the clamping working surface of each flexible contact bladder 405 first makes physical contact with the surface of the car seat frame. Since the magnetorheological fluid in the independent damping cavity 417 is in a liquid state at this time, and the secondary micro excitation coil 418 does not generate a magnetic field, the spherical surface of each micro ball can rotate freely and flexibly within the independent damping cavity 417 with its sphere center as the axis when subjected to the normal pressure and tangential force of the workpiece surface. Since the magnetorheological fluid in the independent damping cavity 417 is in a liquid state at this time, and the secondary micro excitation coil 418 does not generate a magnetic field, the spherical surface of each micro ball can rotate freely and flexibly within the independent damping cavity 417 with its center as the axis when subjected to the normal pressure and tangential force from the workpiece surface. After receiving the pressure signals from all distributed pressure sensors 407, the built-in logic controller immediately analyzes and processes them.

[0032] Furthermore, the built-in logic controller, based on the uneven pressure distribution, directs a weak current through the corresponding secondary micro excitation coil 418 to contact points with excessive pressure. This generates a weak magnetic field, slightly increasing the viscosity of the magnetorheological fluid in the independent damping chamber 417, thereby increasing the rotational damping of the corresponding micro-balls. This increases the rolling resistance of the micro-balls at that point, causing them to tend to stay still rather than continue rolling, thus slowing down the pressure increase rate at that contact point and buying time for other areas to make contact. For areas with zero or insufficient pressure, i.e., empty areas that have not yet made effective contact, the built-in logic controller instructs the micro solenoid valve 404 to open slightly. At this time, depending on the actual usage, the external air pump inflates or releases a small amount of gas through the air pipe 403 into the annular air guide 414 and the corresponding micro control columnar airbag 415. The micro-controlled columnar airbag 415 inflates, pushing the sliding disk 413 and its mounting disk 402 downwards or upwards slightly, thereby pushing or retracting the flexible contact bag 405 in that area closer to the workpiece surface, prompting it to actively seek contact. If the above local adjustment still cannot make the pressure distribution more even, the side auxiliary adjustment mechanism 200 starts to work, finely adjusting the clamping angle of the body contact claw mechanism 300 through slight oscillation or translation.

[0033] By using the above adjustments, the entire flexible contact capsule assembly 400 can contact the complex local curved surface of the workpiece in a very short time, achieving a seamless conformal fit, and ensuring that the pressure at all contact points is controlled within a reasonable range that will neither crush the workpiece nor cause instability in clamping. Finally, the pressure readings at each point gradually tend to be balanced.

[0034] Next, once the built-in logic controller confirms through the distributed pressure sensor 407 that the pressure at all contact points has reached the preset equilibrium range and clamping force threshold, the adaptive conformal stage is successfully completed. At this point, the built-in logic controller issues a strong energizing command to the main electromagnet matrix 305. This causes each main electromagnet in the main electromagnet matrix 305 to independently generate a precisely controllable strong magnetic field based on feedback from the corresponding distributed position pressure sensor 407. This magnetic field acts on the magnetorheological fluid in the main cavity, independent channel 416, magnetorheological fluid secondary chamber 408, and the inner cavity of the flexible contact bladder 405, causing it to solidify instantly. This transforms each flexible contact bladder 405, which has perfectly conformed to the workpiece surface, into a solid pad with sufficient supporting rigidity, precisely replicating and locking the local shape of the workpiece.

[0035] At the same time, the built-in logic controller also sends a strong energizing command to the secondary micro excitation coil 418, which solidifies the magnetorheological fluid in the independent damping cavity 417, firmly locking each micro ball in its current position to prevent it from rolling during subsequent welding vibrations, thus ensuring the absolute stability of the microstructure.

[0036] At this point, the entire clamping surface, from the macroscopic capsule to the microscopic ball bearings, is rigidly locked, and the workpiece is firmly and stress-free clamped. Even under external welding stress, the workpiece will not undergo any slight displacement or deformation.

[0037] For example, if the workpiece surface has a tilt or local protrusion, the distributed pressure sensor 407 on the first contact flexible contact bladder 405 will show a rapid increase in pressure, while the sensor readings on other bladders that have not yet made effective contact will be close to zero. If the workpiece experiences a slight positional deviation in the previous process or during transport, causing its actual arrival position to deviate from the theoretical clamping center, when the fine-tuning ball array 406 on multiple grippers simultaneously contacts the workpiece surface, due to the positional differences at each contact point, the workpiece will apply tangential forces of different directions and magnitudes to the micro-balls at different positions. Under the action of these tangential forces, the micro-balls at the corresponding positions begin to rotate, and their rotation direction is adapted to the direction the workpiece wants to move. Because the rotational resistance of the micro-balls is extremely small, the workpiece is effectively placed on a bed of freely rolling balls. At this point, if the advancing speed of a certain jaw is slightly faster or the clamping force is slightly greater, the micro-balls at its contact point will rotate in the corresponding direction, thereby allowing the workpiece to slide or rotate slightly between the jaws. That is, the workpiece itself does not need to be actively adjusted, but is guided to a mechanically balanced position by these freely rotating micro-balls as multiple jaws gradually approach each other.

[0038] More specifically, when the three jaws in the three-jaw gripper move synchronously towards the center, if there is a deviation in the workpiece position, the micro-balls on the jaw that first contacts the workpiece will rotate due to the reaction force applied by the workpiece. This rotation actually creates space, allowing the workpiece to move towards the jaw that is not in contact or has a smaller contact force. As the jaws continue to advance, the workpiece surface comes into contact with more and more micro-balls, and guided by the rolling of these micro-balls, it automatically finds a stable position that balances the force at each contact point. This process is entirely passively completed by mechanical contact and the free rotation of the micro-balls, without the need for external power to drive the workpiece to actively move; hence, it is called passive workpiece displacement or workpiece self-positioning.

[0039] Once the workpiece reaches a position of force equilibrium through the aforementioned passive displacement mechanism, the pressure at each point monitored by the distributed pressure sensor 407 begins to converge. At this point, the built-in logic controller determines whether the ideal clamping posture has been achieved based on the pressure signal. Before entering the magnetorheological fluid solidification and locking stage, the built-in logic controller can, as needed, supply a weak current to the secondary micro excitation coil 418 to generate a weak magnetic field, appropriately increasing the viscosity of the magnetorheological fluid in the independent damping cavity 417. This provides a certain rotational damping for the micro-ball bearings, preventing them from rolling unexpectedly during subsequent minor vibrations and thus maintaining their posture.

[0040] Subsequently, the welding robot begins welding the corresponding parts of the seat frame. Throughout the welding process, the distributed pressure sensor 407 remains continuously operational, monitoring changes in clamping force at various points in real time. If abnormal fluctuations in clamping force due to thermal expansion or stress release are detected, the built-in logic controller can immediately fine-tune the magnetic field strength of the electromagnets in the corresponding area of ​​the main electromagnet matrix 305. For example, it can demagnetize and re-excite within a very small range to achieve minute stress release, or perform minute force compensation through the side auxiliary adjustment mechanism 200 to ensure the optimal clamping state is maintained, effectively suppressing welding deformation and guaranteeing welding accuracy. After the welding process is completed, the entire device structure returns to its original position and awaits instructions for the next work cycle.

[0041] Preferred, according to Figure 4 As shown, the drive mechanism 100 includes: a drive member 101; a gear set 102 connected to the output end of the drive member 101; a transmission threaded rod 103 connected to the top gear in the gear set 102; an external transmission threaded sleeve 104 connected to the external thread of the transmission threaded rod 103, and the side end of the external transmission threaded sleeve 104 is hinged to the drive rod 304.

[0042] The drive component 101 is a servo motor or hydraulic motor used to output rotational power. A gear set 102, consisting of at least two meshing gears, is connected to the output end of the drive component 101 to achieve speed reduction and torque amplification. The top gear in the gear set 102 is fixedly connected to a transmission threaded rod 103, thereby transmitting rotational motion to the transmission threaded rod 103. An external transmission threaded sleeve 104 is threadedly connected to the external thread of the transmission threaded rod 103, and the internal thread of the external transmission threaded sleeve 104 engages with the external thread of the transmission threaded rod 103 to form a screw-nut pair. The side end of the external transmission threaded sleeve 104 is hinged to the drive rod 304. When the drive component 101 rotates, the gear set 102 reduces speed and increases torque, driving the transmission threaded rod 103 to rotate, which in turn drives the external transmission threaded sleeve 104 to move linearly along the axial direction, ultimately transmitting power to the drive rod 304 to achieve the advancement and retraction of the contact claw clamping mechanism 300.

[0043] Preferred, according to Figures 1-4As shown, the side adjustment mechanism 200 includes: a mounting section 201 connected to a side end and a multi-hinged rod 302; a rotating shaft 204 rotatably mounted inside the mounting section 201, with a first half-ring gear 203 sleeved on the outer side end of the rotating shaft 204, and a first gear drive 202 meshing with the side end of the first half-ring gear 203; a rotating shaft support 206 rotatably connected to the bottom end of the rotating shaft 204, with a second half-ring gear 207 sleeved on the outside of the rotating shaft in the rotating shaft support 206, and a second gear drive 208 meshing with the bottom end of the second half-ring gear 207; a second contact 210 rotatably connected to the bottom end of the first contact 205; and a section connector 220 connected to the bottom of the rotating shaft support 206, which is used to connect the first contact 205 and the second contact 210.

[0044] Specifically, when the workpiece surface has a large overall tilt or angular deviation, the built-in logic controller activates the side auxiliary adjustment mechanism 200 to perform overall attitude fine-tuning. When adjusting the horizontal swing angle, the built-in logic controller instructs the first gear drive 202 to rotate, driving the first half-ring gear 203 to rotate. The first half-ring gear 203 drives the rotating shaft 204 to rotate, causing the rotating shaft column 206 and the entire contact claw clamping mechanism 300 below it to swing horizontally around the axis of the rotating shaft 204. When adjusting the vertical pitch angle, the built-in logic controller instructs the second gear drive 208 to rotate, driving the second half-ring gear 207 to rotate. The second half-ring gear 207 drives the second contact member 210 to pitch relative to the first contact member 205. This pitch motion is transmitted to the entire contact claw clamping mechanism 300 through the joint connector 220. These two levels of adjustment can be performed independently or in conjunction, achieving fine-tuning of the spatial attitude of the contact claw clamping mechanism 300 and ensuring good contact between all flexible contact pouches 405 and the workpiece surface.

[0045] Further preferred, based on Figure 1As shown, the built-in logic controller is used to control the auxiliary excitation coil 409 and the secondary micro excitation coil 418 to be energized before the clamping mechanism contacts the workpiece, keeping all flexible contact bladders 405 in a soft and collapsed state. After the clamping mechanism is fully attached to the workpiece, according to the preset clamping requirements, the power supply of the auxiliary excitation coil 409 corresponding to the target flexible contact bladder 405 is selectively disconnected, and the corresponding main electromagnet is energized at the same time, so that the magnetorheological fluid flows into and solidifies the target flexible contact bladder 405 first, forming a support surface with the curvature of the workpiece surface. The built-in logic controller supplies a first current to the secondary micro excitation coil 418, causing the magnetorheological fluid in the independent damping cavity 417 to completely solidify and lock the micro ball. The built-in logic controller supplies a second current, lower than the first current, to the secondary micro excitation coil 418, causing the magnetorheological fluid in the independent damping cavity 417 to be in a semi-solid state, providing controllable damping for the rotation of the micro ball, so that the workpiece can achieve controlled passive displacement under the action of welding thermal stress. The built-in logic controller is signal-connected to the displacement sensor. The built-in logic controller receives the feedback signal from the displacement sensor and applies a directional pulse current to the auxiliary excitation coil 409 corresponding to the target micro ball, so that it generates an instantaneous driving torque and drives the workpiece to perform micron-level displacement reset.

[0046] Specifically, when the contact claw clamping mechanism 300 reaches the predetermined working area, the built-in logic controller begins to execute the selective contact bladder deployment program according to the preset clamping strategy. The controller first sends a de-energizing command to the auxiliary excitation coil 409 in the target area, and simultaneously sends a weak energizing command to the corresponding main electromagnet matrix 305 unit. After the auxiliary excitation coil 409 is de-energized, the magnetorheological fluid in the secondary chamber 408 of that area regains its fluidity. Under the pressure difference between the main chamber and the secondary chamber, the magnetorheological fluid flows into the inner cavity of the corresponding flexible contact bladder 405 through the magnetorheological fluid distributor 411, causing it to slowly fill and expand, presenting a soft initial state. Meanwhile, the flexible contact bladders 405 in other non-target areas remain collapsed because the auxiliary excitation coil 409 is still energized. This selective deployment strategy allows the device to prioritize the contact of the flexible contact bladders 405 in specific areas with the workpiece shape, forming initial support points.

[0047] At this time, the built-in logic controller sends an instruction to the secondary micro excitation coil 418 corresponding to these target flexible contact bladders 405, switching the current from the first current to the second current, which is lower than the first current, so that the magnetorheological fluid in the independent damping cavity 417 changes from a completely solidified state to a semi-solid state, providing controllable damping for the rotation of the micro ball bearings. The welding robot begins to work on the seat frame.

[0048] Welding is performed on the corresponding parts. During welding, the workpiece may experience slight deformation due to thermal stress. To release this stress, the built-in logic controller switches the current flowing through the secondary micro excitation coil 418 in a certain area from a first current to a second current, causing the magnetorheological fluid in the corresponding independent damping cavity 417 to become semi-solid, providing controllable damping for the rotation of the micro-balls. In this way, under the action of welding thermal stress, the workpiece can drive the micro-balls to rotate slowly, achieving micron-level controlled passive displacement, thereby releasing internal stress and preventing welding deformation. During this process, the distributed pressure sensor 407 and the external displacement sensor monitor the pressure changes and displacement of the workpiece in real time and feed the data back to the built-in logic controller.

[0049] After the welding process is completed and the workpiece cools, the built-in logic controller determines whether the workpiece has shifted based on the signal from the displacement sensor. If a deviation between the workpiece position and the theoretical position is detected, the controller initiates an active reset procedure: the controller applies a directional pulse current to the auxiliary excitation coil 409 in the area where the deviation occurred. Since the auxiliary excitation coil 409 is sleeved outside the magnetorheological fluid secondary chamber 408, the pulse current generates an instantaneous, directional magnetic field. This magnetic field acts on the magnetorheological fluid within the secondary chamber 408 and is then transmitted to the micro-ball bearings through the magnetorheological fluid distributor 411 and the independent damping cavity 417, subjecting the micro-ball bearings to an instantaneous driving torque. This torque drives the micro-ball bearings to rotate, thereby propelling the workpiece to a micrometer-level displacement, gradually resetting the workpiece to the theoretical position. The controller repeatedly performs detection, pulse driving, and re-detection through closed-loop control until the deviation value fed back by the displacement sensor returns to zero.

[0050] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive conformal clamping device for welding automotive seat frames, characterized in that, Includes a clamping mechanism configured with a three-jaw structure, wherein the clamping mechanism of one jaw includes: Drive mechanism (100); The contact claw clamping mechanism (300) is installed on the side of the drive mechanism (100), and its interior is provided with a main cavity for accommodating magnetorheological fluid; A side adjustment mechanism (200) is installed at the bottom of the drive mechanism (100) and is used to cooperate with the contact claw clamping mechanism (300) to clamp the workpiece; A flexible contact bladder assembly (400) is embedded in the clamping working surface of the contact claw clamping mechanism (300). The flexible contact bladder assembly (400) includes multiple independent flexible contact bladders (405). The top of the inner cavity of each flexible contact bladder (405) is sequentially connected to a miniature one-way check valve (410), a magnetorheological fluid secondary chamber (408), and an independent channel (416). The independent channel (416) is connected to the main cavity. A fine-tuning ball array (406) is embedded in the clamping working surface of each flexible contact bladder (405). The fine-tuning ball array (406) includes multiple independently arranged miniature balls. The spherical surface of the miniature balls is slightly higher than the surface of the flexible contact bladder (405) for contacting the workpiece. A distributed pressure sensor (407) is installed at the bottom of each flexible contact bladder (405) for real-time monitoring of the clamping pressure at the corresponding contact point and generating a pressure signal. The contact claw gripper mechanism (300) includes: The main electromagnet matrix (305) is fixed at the bottom of the main cavity and is correspondingly set with multiple independent flexible contact bladders (405). It is used to generate a magnetic field when energized, so as to drive the magnetorheological fluid in the main cavity to flow into the corresponding flexible contact bladder (405) and solidify it.

2. The adaptive conformal clamping device for welding automotive seat frames according to claim 1, characterized in that: The contact claw gripping mechanism (300) further includes: The built-in logic controller is electrically connected to the main electromagnet matrix (305) and the distributed pressure sensor (407) respectively, and is used to receive pressure signals and independently control the energizing state of each main electromagnet. A drive rod (304) is connected to the actuating end of the drive mechanism (100); The top surface of the slotted frame (301) is provided with a slot to allow space for the drive rod (304) to move, and the side wall surface of the slotted frame (301) is provided with an arc groove (303). The multi-hinged rod (302) is connected at one end to the frame at the bottom of the drive mechanism (100), and at the other end is rotatably connected to the shaft and the arc groove (303).

3. The adaptive conformal clamping device for welding automotive seat frames according to claim 1, characterized in that: The contact claw gripper mechanism (300) further includes: The main electromagnet mounting contact seat (306) is hinged to the side end of the drive rod (304) for mounting the main electromagnet; The middle drive rod frame (307) is hinged to the slot frame (301), and the side end of the middle drive rod frame (307) is hinged to the end drive rod frame (308). The bottom of the drive rod (304), the middle drive rod frame (307) and the end drive rod frame (308) are respectively connected to the main electromagnet mounting contact seat (306).

4. The adaptive conformal clamping device for welding automotive seat frames according to claim 1, characterized in that: The flexible contact pouch assembly (400) further includes: The mounting cavity (401) is embedded in the bottom surface of the main electromagnet mounting contact seat (306); Mounting plate (402), which is coaxially disposed at the bottom of mounting cavity (401), is used to limit the fine-tuning ball array (406) and the distributed pressure sensor (407). The sliding plate (413) is integrated with the mounting plate (402); An outer sliding frame (412) is installed at the bottom of the mounting cavity (401). The connection end of the outer sliding frame (412) and the sliding disk (413) has an installation space. An annular air guide (414) is installed inside the installation space. A miniature control columnar airbag (415) is arranged around the annular air guide (414). The miniature control columnar airbag (415) and the sliding edge of the sliding disk (413) are correspondingly arranged.

5. The adaptive conformal clamping device for welding automotive seat frames according to claim 1, characterized in that: The flexible contact bladder assembly (400) also includes: An air pipe (403) is embedded in the body of the mounting cavity (401) and is used to connect to an external air pump. A miniature solenoid valve (404) is installed on the side end of the air pipe (403). An auxiliary excitation coil (409) is sleeved outside the magnetorheological fluid sub-chamber (408) and electrically connected to the built-in logic controller. It is used to energize the clamping mechanism before it comes into contact with the workpiece to generate a magnetic field to lock the magnetorheological fluid in the magnetorheological fluid sub-chamber (408) and prevent it from flowing into the flexible contact bladder (405). A magnetorheological fluid distributor (411) is installed at the bottom of a miniature one-way check valve (410) and inside a flexible contact bladder (405).

6. The adaptive conformal clamping device for welding automotive seat frames according to claim 1, characterized in that: Each of the micro-balls is provided with an independent damping cavity (417) below it. The independent damping cavity (417) is connected to the annular directional pipe at the bottom of the micro one-way check valve (410). The independent damping cavity (417) is isolated from the inner cavity of the flexible contact bladder (405) and filled with magnetorheological fluid. The bottom of the micro-ball is immersed in the magnetorheological fluid of the independent damping cavity (417). A secondary micro excitation coil (418) is provided around each of the independent damping cavities (417). The secondary micro excitation coil (418) is electrically connected to the built-in logic controller and is used to independently control the rotational damping force of the micro-ball.

7. The adaptive conformal clamping device for welding automotive seat frames according to claim 2, characterized in that: The built-in logic controller is used to control the auxiliary excitation coil (409) and the secondary micro excitation coil (418) to be energized before the clamping mechanism contacts the workpiece, so as to keep all flexible contact bladders (405) in a soft and collapsed state.

8. The adaptive conformal clamping device for welding automotive seat frames according to claim 2, characterized in that: The built-in logic controller is used to selectively disconnect the power supply of the auxiliary excitation coil (409) corresponding to the target flexible contact bladder (405) according to the preset clamping requirements after the clamping mechanism is fully attached to the workpiece, and at the same time energize the corresponding main electromagnet so that the magnetorheological fluid flows into and solidifies the target flexible contact bladder (405) first, forming a support surface with the curvature of the workpiece surface.

9. The adaptive conformal clamping device for welding automotive seat frames according to claim 2, characterized in that: The built-in logic controller supplies a first current to the secondary micro excitation coil (418), causing the magnetorheological fluid in the independent damping cavity (417) to be completely solidified for locking the micro ball. The built-in logic controller supplies a second current lower than the first current to the secondary micro excitation coil (418), causing the magnetorheological fluid in the independent damping cavity (417) to be in a semi-solid state, providing controllable damping for the rotation of the micro ball, so as to allow the workpiece to achieve controlled passive displacement under the action of welding thermal stress.

10. The adaptive conformal clamping device for welding automotive seat frames according to claim 2, characterized in that: The built-in logic controller is connected to the external displacement sensor of the workpiece. The built-in logic controller receives the feedback signal from the displacement sensor and applies a directional pulse current to the auxiliary excitation coil (409) corresponding to the target micro ball, so that it generates an instantaneous driving torque and drives the workpiece to perform micron-level displacement reset.

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