A force-controlled servo gripper for thin-walled aeronautical cylinders

Abstract

The present application belongs to the field of aviation manufacturing and automatic clamping technology, and particularly relates to a force control type servo clamping jaw for an aviation thin-walled cylindrical part. The force control type servo clamping jaw comprises an upper mounting plate, a worm and gear reducer, a reducer support and a clamping jaw assembly. The clamping jaw assembly is composed of a fixed end clamping jaw and a movable end clamping jaw which can move along a guide rail, and is provided with a support jaw assembly with a force sensor. The present application drives the support jaw to support the tool assembly support groove at both ends of the workpiece through a bidirectional threaded screw rod, so as to avoid thin-walled deformation. The force sensor is combined to control the clamping force in a closed loop, and the movable end clamping jaw has the functions of self-adaptive adjustment and active vibration suppression, so that the present application is suitable for safe and stable carrying of thin-walled cylindrical parts of various specifications.

Description

Technical Field

[0001] This invention relates to the field of aerospace manufacturing and automated clamping technology, specifically to a force-controlled servo gripper for thin-walled cylindrical aerospace components. Background Technology

[0002] In the field of automated material handling, servo-driven clamps have been applied. For example, patent CN211729221U discloses a double-clamp structure, in which a servo motor drives a trapezoidal lead screw to rotate via a transmission mechanism, driving the jaws to open and close to clamp rod-shaped workpieces. The clamping force can be changed by adjusting the motor torque. This type of solution is suitable for conventional rigid workpieces, but for thin-walled cylindrical parts in aerospace applications, the thin walls and low rigidity make it easy for the radial force applied to the outer wall to cause deformation, thus limiting the clamping method. Furthermore, the jaw spacing is relatively fixed, requiring manual adjustment when changing workpiece specifications, making it difficult to quickly adapt to multi-variety production. It also lacks a force feedback closed-loop and vibration suppression mechanism, resulting in insufficient clamping stability during handling. In addition, in actual production, after multiple machine tools complete the workpiece potting and shaping, the placement posture of the workpiece and end fixtures in the horizontal plane often exhibits inconsistencies, showing angular deviations such as the axis turning inward or outward. However, the precision indexing accuracy of the machine tool rotary table used for subsequent clamping is limited, and its zero-point positioning device has strict requirements for the angular alignment tolerance of the workpiece. When the deviation of the workpiece's placement angle exceeds the indexing compensation range of the rotary table itself, it will be impossible to complete the precise assembly of the workpiece and the rotary table, which further restricts the adaptability and production efficiency of automated loading and unloading.

[0003] To address this issue, the present invention provides a force-controlled servo gripper. A worm gear reducer drives the gripper assembly to rotate around a vertical axis, adapting to workpiece placement angle deviations. A movable end gripper, capable of moving along a guide rail, allows for flexible adjustment of the distance between the two grippers based on the workpiece length. The grippers provide support from tooling component support slots at both ends of the workpiece, avoiding radial clamping forces. The support gripper assembly is equipped with a force sensor to achieve closed-loop control of the clamping force, thereby ensuring the safe handling of thin-walled cylindrical parts. Summary of the Invention

[0004] The present invention aims to provide a force-controlled servo gripper for thin-walled cylindrical parts in aerospace applications. Through a support-type clamping structure, an adjustment mechanism that can adapt to the length and angle of the workpiece, and closed-loop control by a force sensor, it can achieve deformation-free safe clamping and highly stable automated handling of thin-walled cylindrical parts.

[0005] A force-controlled servo gripper for thin-walled cylindrical parts in aerospace applications, comprising: The upper mounting plate has its top for fixed connection with the slide ram; The worm gear reducer has its housing fixedly connected to the bottom of the upper mounting plate; The reducer bracket is connected to the inner ring of the worm gear reducer and can rotate around the vertical axis a (R-axis rotation) under the drive of the first servo motor. The gripper assembly, installed below the reducer bracket, is used to clamp the workpiece; The gripper assembly includes a stationary gripper and a moving gripper. The stationary gripper is fixedly connected to one side of the bottom of the reducer bracket, and the moving gripper is mounted on the slider of the first guide rail via a mounting plate and can move relative to the stationary gripper along the first guide rail to accommodate workpieces of different lengths.

[0006] The outer housing of the worm gear reducer is fixedly connected to the upper mounting plate. The reducer bracket is connected to the inner ring of the worm gear reducer and rotates around the vertical axis (Z-axis) under the drive of the first servo motor, thus giving the entire gripper assembly rotational freedom around the Z-axis. This rotational adjustment function allows the gripper assembly to adapt to deviations in the workpiece placement angle. The moving end gripper is mounted on the slider of the first guide rail via the mounting plate and can move relative to the stationary end gripper along the first guide rail, i.e., the X-axis direction, allowing the gripper assembly to flexibly adjust the distance between the two grippers according to the workpiece length. This structure allows a single gripper device to adapt to various length specifications of aerospace thin-walled cylindrical parts, effectively improving the versatility and compatibility of the equipment. The gripper assembly supports and clamps the workpiece from both ends against the support grooves of the tooling assembly, avoiding the radial clamping force generated by the traditional gripper directly clamping the outer wall of the thin-walled cylindrical part, thus eliminating the risk of the thin-walled cylindrical part being flattened and deformed from the clamping method. The gripper assembly can also move along the Z-axis with the slide block, enabling stable lifting and handling of the workpiece, providing a structural basis for force-controlled servo clamping.

[0007] Optionally, the slide is fixedly installed on the slide moving plate, the slide moving plate is set on the crossbeam frame and can reciprocate in the horizontal direction; the slide moving plate is provided with a first drive motor, the crossbeam frame is fixedly provided with a rack in the horizontal direction, the output shaft of the first drive motor is provided with a first gear, and the first gear meshes with the rack for transmission; The sliding ram is equipped with a second drive motor and a third guide rail. A second gear is mounted on the output shaft of the second drive motor, and a rack section is vertically mounted on the ram. The second gear meshes with the rack section to drive the ram to move vertically along the third guide rail. The sliding ram, through the meshing of the first drive motor, the first gear, and the rack on the crossbeam, can reciprocate horizontally, allowing the gripper assembly to achieve a wide range of horizontal displacement, thus expanding the gripper's working coverage and facilitating workpiece transfer between multiple workstations. Simultaneously, the ram, through the meshing of the second drive motor, the second gear, and the vertical rack section on the ram, and guided by the third guide rail, can precisely lift and lower vertically, ensuring the smoothness and positioning accuracy of the workpiece handling process. The horizontal movement and vertical lifting are controlled by independent drive motors, with the two axes' movements decoupled, allowing the gripper assembly to flexibly adjust to the target gripping position according to the workpiece's spatial location. Furthermore, the combination of gear and rack transmission with guide rail ensures the transmission rigidity and straightness of the gripper assembly during movement, avoiding the impact of skew or vibration on the sensor's detection accuracy, thus providing a reliable structural foundation for the stable implementation of force-controlled clamping.

[0008] Optionally, the gripper assembly is equipped with a lead screw arranged along the moving direction of the moving gripper. The lead screw can rotate to drive the moving gripper to move along the first guide rail. A guide rail brake seat is provided on the moving gripper. After the moving gripper moves to a predetermined position, it is locked and fixed to the first guide rail by the guide rail brake seat.

[0009] There are two drive methods for the lead screw: manual drive and manual operation. The manual drive has a handwheel at one end, which rotates the lead screw to move the moving jaw along the first guide rail. Operators can manually adjust the position without additional tools, making operation simple and the adjustment process continuously controllable. The position of the moving jaw can be precisely set according to the actual length of the workpiece. After the moving jaw moves to the predetermined position, it is locked to the first guide rail by the guide rail brake seat. This locking structure reliably maintains the position of the moving jaw after adjustment, preventing accidental displacement of the moving jaw due to vibration or external force during clamping, and ensuring that the distance between the two jaws remains stable during clamping and handling.

[0010] Another optional lead screw drive method is electric drive. One end of the lead screw is driven by a rotary motor 56 (the rotary motor can be coupled to the lead screw via a coupling). The drive motor drives the lead screw to rotate, thereby driving the moving end gripper to move along the first guide rail. The guide rail brake can be an electrically controlled brake. After the moving end gripper moves to the predetermined position, it can be electrically locked. This drive method is suitable for automated control and is controlled by a single control unit.

[0011] Optionally, the stationary end gripper and the moving end gripper each include: Servo motor; The speed reducer is connected to the servo motor; A bidirectional threaded screw is connected to a speed reducer and is driven to rotate by a servo motor. The system includes at least two support claw assemblies, each consisting of a nut seat that engages with a bidirectional threaded screw. The nut seat is slidably mounted on a second guide rail. Rotation of the bidirectional threaded screw drives the two support claw assemblies to move towards or away from each other along the second guide rail, thus clamping or releasing the workpiece. A servo motor drives the bidirectional threaded screw to rotate via a reducer, causing the two support claw assemblies to move synchronously towards or away from each other along the second guide rail, achieving centered clamping and releasing of the workpiece. The bidirectional threaded screw ensures equal displacement of the support claw assemblies on both sides, guaranteeing that the workpiece's axial position does not shift during clamping, effectively improving the repeatability of the clamping. Compared to traditional pneumatic or hydraulic grippers, the servo motor and reducer drive method allows for precise control of the support claw feed based on changes in the workpiece diameter, avoiding excessive or insufficient clamping force caused by fluctuations in the workpiece's outer diameter tolerance. This provides a controllable power basis for the safe clamping of thin-walled cylindrical parts. The support claw is mounted on the second guide rail and slides along it. The guide rail constrains the movement direction of the support claw to ensure the linearity and stability of the clamping action and reduce the additional torque on the workpiece caused by the movement deviation.

[0012] Furthermore, a force sensor is installed on the support claw assembly. This force sensor contacts the workpiece during clamping and senses the radial clamping force. The support claw assembly has a protrusion, and both ends of the workpiece are tooling assemblies with support grooves. The force sensor contacts the workpiece during clamping and generates a radial clamping force. This signal can be fed back to the control system in real time, allowing the servo motor's drive quantity to be dynamically adjusted based on the sensor feedback, achieving closed-loop control of the clamping force. Even if there is a large tolerance in the workpiece's outer diameter, the movement of the support claw assembly can still adaptively adjust according to the actual contact state, ensuring consistent clamping tightness each time and effectively preventing deformation of the thin-walled cylindrical part due to excessive clamping force. The support claw assembly has a protrusion, and the tooling assemblies at both ends of the workpiece have support grooves. During clamping, the protrusion is radially inserted into the support groove along the direction of the second guide rail. This concave-convex fit structure concentrates the clamping force onto the tooling assembly rather than the thin-walled cylindrical body itself, further eliminating the deformation risk caused by the clamping force being directly applied to the thin-walled surface, while ensuring the axial and circumferential positioning reliability of the workpiece in the clamping state.

[0013] Optionally, the support claw assembly includes a support claw and a movable plate; The support claw has several slotted holes, which are bolted to the moving plate. The bottom of the moving plate has a locking plate with locking holes containing locking pins to lock the sides of the support claw. The top of the support claw also has several slotted holes, which are bolted to the moving plate. These slotted holes allow the mounting position of the support claw relative to the moving plate to be adjusted within a certain range, enabling the initial distance between the two support claws to be adjusted according to the workpiece diameter. This allows the same claw to accommodate thin-walled cylindrical aerospace parts with different radial dimensions, further improving the equipment's compatibility.

[0014] The locking plate is fixed to the bottom surface of the moving plate. The locking plate has locking holes, and locking pins are installed in the locking holes to lock the sides of the support claws. This locking structure adds lateral positioning constraints to the bolt connection of the waist hole, effectively preventing the support claws from slipping or deflecting along the waist hole direction during clamping force, and significantly improving the installation rigidity and position retention accuracy of the support claws.

[0015] The combination of diameter adaptation adjustment via the waist hole and fastening locking via the locking pin enables the support claw to meet the clamping requirements of different workpiece diameters while maintaining a stable and reliable working state under high clamping force conditions, avoiding clamping offset or failure due to loose connection.

[0016] Optionally, it also includes a control unit, which is configured to: The amount of movement of the moving end gripper along the first guide rail is determined according to the length of the workpiece, so that the distance between the two end grippers matches the distance between the support grooves at both ends of the workpiece. The spatial height position of the workpiece axis is determined based on the diameter of the workpiece, and the vertical movement of the gripper assembly is determined by the constraint that the support groove is located on the horizontal plane of the axis, so that the protrusion of each support gripper assembly is aligned with the corresponding support groove in the height direction. Based on the diameter of the workpiece and the position of the support groove relative to the axis, determine the radial movement of each support claw assembly along the second guide rail so that the protrusion can be inserted into the support groove radially. Based on the workpiece's spatial reference position and axis height, determine the horizontal movement of the gripper assembly and move the gripper assembly to the gripping position. Based on the weight of the workpiece and the static friction coefficient between the support claw and the tooling assembly, the target value of the radial clamping force required during the handling process is calculated. During the clamping process, the output torque of the servo motor is controlled in a closed loop based on the actual radial clamping force signal measured by the force sensor, so that the actual radial clamping force reaches the target value.

[0017] The control unit automatically calculates the movement of the moving jaw, the vertical movement of the jaw assembly, the radial movement of the support jaw assembly, and the horizontal movement of the jaw assembly. This enables the jaw assembly to adaptively match and precisely position the workpiece based on its length, diameter, and spatial orientation, without requiring manual intervention. The control unit calculates the target clamping force based on the workpiece weight and a preset safety factor, and uses a closed-loop control system based on the radial clamping force from the force sensor to precisely and consistently control the output torque of the servo motor. This ensures that the actual clamping force remains accurate and constant, avoiding fluctuations in clamping force caused by workpiece outer diameter tolerances, and effectively guaranteeing the clamping safety and consistency of thin-walled cylindrical aerospace components.

[0018] Furthermore, the control unit is also configured as follows: When the protrusion of the support claw assembly approaches the support groove, the support claw assembly is first driven to feed rapidly in position mode; when the force sensor detects the change in radial clamping force caused by contact, it switches to torque mode and gradually applies the target radial clamping force. After the workpiece is lifted, the fluctuation of the radial clamping force measured by the force sensor is continuously monitored. When the fluctuation exceeds a preset threshold, abnormal vibration of the workpiece is determined, and clamping force compensation is performed to suppress the vibration. The control unit first drives the support claw assembly to feed rapidly in position mode when the protrusion approaches the support groove. After contact, it switches to torque mode and gradually applies the target clamping force. This control strategy ensures clamping efficiency and avoids damage to the thin-walled cylindrical part caused by the impact force generated by high-speed contact. By continuously monitoring the fluctuation of the radial clamping force measured by the force sensor after the workpiece is lifted, and determining abnormal vibration and performing clamping force compensation when the fluctuation exceeds a preset threshold, real-time suppression of dynamic interference is achieved, effectively improving the stability and safety of the clamping state during the handling process.

[0019] Furthermore, the control unit is also configured as follows: During the process of the slide moving the workpiece, the radial clamping force signal of the force sensor is collected in real time, and the signal is subjected to spectrum analysis. When a low-frequency oscillation component exceeding a preset background noise level is detected in the signal, it is determined to be a horizontal oscillation caused by workpiece movement. Based on this, the motion parameters of the slide block and / or the clamping force of the servo motor are adjusted to prevent further vibration and workpiece damage. The control unit collects the radial clamping force from the force sensor in real time during the slide block's movement of the workpiece and performs spectral analysis on the signal. When a low-frequency oscillation component exceeding a preset background noise level is detected, it is determined to be a horizontal oscillation caused by workpiece movement. Based on this, the motion parameters of the slide block or the clamping force of the servo motor are adjusted. Compared to methods that rely solely on amplitude thresholds, this spectral analysis mechanism can effectively distinguish between normal vibration and abnormal oscillation, avoiding misjudgment. By adjusting motion parameters to reduce disturbance energy at the excitation source level, or by adjusting the clamping force to change system stiffness to enhance vibration resistance, these dual suppression methods work together to significantly reduce the risk of damage to thin-walled cylindrical parts due to increased vibration during handling.

[0020] Optionally, the control unit is also configured to: The gripper assembly and the workpiece are considered as an equivalent mass-spring-damping system, and the current damping ratio of the system is identified during non-handling periods based on the historical fluctuation signals recorded by the force sensor during previous handling processes. When the identified damping ratio is lower than the preset stability threshold, the basic clamping force setting of the servo motor is adjusted in the next batch or the next clamping to change the stiffness of the equivalent system, thereby optimizing the dynamic stability of the subsequent handling process.

[0021] The control unit treats the gripper assembly and workpiece as an equivalent mass-spring-damped system. During transport intervals, it identifies the current damping ratio based on the fluctuation characteristics of the radial clamping force from the force sensor. This allows it to acquire the system's dynamic characteristics based on its own response data without the need for external measuring equipment. When the identified damping ratio falls below a preset stability threshold, it indicates that the system is underdamped under the current clamping parameters. The control unit then appropriately increases the base clamping force setting in the next batch or the next clamping operation to change the stiffness of the equivalent system, causing the damping ratio to rise above the stability threshold. This adaptive base clamping force mechanism based on damping state feedback improves the dynamic response of the clamping structure from the perspective of the system's inherent characteristics. It effectively suppresses continuous vibration during transport, offering a more targeted and fundamental approach compared to passive vibration isolation or post-compensation methods, further enhancing the stability and robustness of the clamping system under complex working conditions.

[0022] The advantages of this invention are as follows: the gripper assembly provides support clamping from the tooling component support grooves at both ends of the workpiece, completely avoiding the risk of deformation caused by radial clamping force; the worm gear reducer gives the gripper assembly rotational freedom around the vertical axis, which can not only adapt to workpiece placement angle deviations, but also coordinate with the horizontal moving axis to achieve linkage alignment between the horizontal movement of the sliding plate and the rotation R-axis; for workpiece axis misalignment caused by multiple machine tool layouts on site, the angle deviation of the workpiece can be corrected in advance during the gripping stage, adjusting the workpiece posture to within the indexing accuracy compatibility range of the machine tool's fourth-axis servo turntable, ensuring smooth clamping between the workpiece end tooling and the turntable zero-point positioning device. The support gripper assembly is equipped with a force sensor to achieve closed-loop control of the clamping force, ensuring precise and constant clamping; the control unit has online identification of the system damping ratio and active stiffness modulation functions, which can monitor and suppress vibration in real time during the handling process, ensuring dynamic stability. This invention comprehensively improves the safety, reliability, and robustness of automated handling of aerospace thin-walled cylindrical parts from clamping method, size adaptability, force control accuracy to dynamic vibration suppression. Attached Figure Description

[0023] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall device of the present invention.

[0025] Figure 2 This is a schematic diagram of the interior of the back of the crossbeam frame of the present invention.

[0026] Figure 3 This is a schematic diagram of the first drive motor and rack of the present invention.

[0027] Figure 4 This is a schematic diagram of the first gear, rack, second drive motor, and third guide rail of the present invention.

[0028] Figure 5 For the present invention Figure 4 A magnified view of a portion of the image.

[0029] Figure 6 This is a schematic diagram of the worm gear reducer of the present invention.

[0030] Figure 7 This is a schematic diagram of the speed reducer bracket, upper mounting plate, and gripper assembly of the present invention.

[0031] Figure 8 This is a schematic diagram of the lead screw driven gripper assembly of the present invention.

[0032] Figure 9 This is a schematic diagram of the support claw assembly and the bidirectional threaded screw of the present invention.

[0033] Figure 10 This is a schematic diagram of the first guide rail and the moving end gripper of the present invention.

[0034] Figure 11 This is a schematic diagram of the locking plate, waist hole, moving plate, and locking pin of the present invention.

[0035] Figure 12 This is a schematic diagram of the workpiece of the present invention.

[0036] Figure 13 This is a schematic diagram of the tooling components of the present invention.

[0037] Figure 14 This is a schematic diagram of the protrusion and force sensor of the present invention.

[0038] Figure 15 This is Embodiment 2 of the present invention. Figure Descriptions: 1-Upper mounting plate, 2-Slide block, 3-Worm gear reducer, 31-Reducer bracket, 41-First servo motor, 5-Gripper assembly, 51-Stationary gripper, 52-Moving gripper, 52a-Guide rail brake seat, 53-Mounting plate, 54-First guide rail, 55-Lead screw, 55a-Handwheel, 56-Rotary motor, 61-Servo motor, 62-Reducer, 63-Double-direction threaded screw, 64-Support gripper assembly, 64a-Force Sensor, 64b-support claw, 64c-moving plate, 64d-waist hole, 64e-locking plate, 64g-locking pin, 64h-protrusion, 65-second guide rail, 7-crossbeam frame, 71-rack, 21-slide ram moving plate, 21a-first drive motor, 21b-first gear, 21c-second drive motor, 21d-third guide rail, 81-second gear, 22-rack part, 9-workpiece, 91-tooling assembly, 91a-support groove. Detailed Implementation

[0039] 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.

[0040] The concepts involved in this application will first be described with reference to the accompanying drawings. It should be noted that the following descriptions of various concepts are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] Example 1: like Figure 1 As shown, this embodiment provides a force-controlled servo gripper for thin-walled cylindrical parts in aerospace applications, with the following overall structure. The top of the upper mounting plate 1 is fixedly connected to the slide ram 2, the outer housing of the worm gear reducer 3 is fixedly connected to the bottom of the upper mounting plate 1, the reducer bracket 31 is connected to the inner ring of the worm wheel of the worm gear reducer 3 and can rotate around the vertical axis a under the drive of the first servo motor 41, and the gripper assembly 5 is installed below the reducer bracket 31 for gripping the workpiece 9.

[0042] The gripper assembly 5 includes a stationary gripper 51 and a moving gripper 52. The stationary gripper 51 is fixedly connected to one side of the bottom of the reducer bracket 31. The moving gripper 52 is mounted on the slider of the first guide rail 54 via the mounting plate 53 and can move along the first guide rail 54 relative to the stationary gripper 51 to accommodate workpieces 9 of different lengths.

[0043] The outer housing of the worm gear reducer 3 is fixedly connected to the upper mounting plate 1, such as... Figure 6 As shown, the reducer bracket 31 is connected to the inner ring of the worm gear reducer 3 and rotates around axis a under the drive of the first servo motor 41. Thus, the entire gripper assembly 5 gains rotational freedom around axis a, as shown in the diagram. Figure 7 , Figure 8 As shown, the gripper assembly 5 can adapt to deviations in the placement angle of the workpiece 9. The moving end gripper 52 is mounted on the slider of the first guide rail 54 via the mounting plate 53, and can move relative to the stationary end gripper 51 along the first guide rail 54, i.e., the X-axis direction. Figure 10 As shown, the gripper assembly 5 can flexibly adjust the distance between the two grippers according to the length of the workpiece 9, so that a single gripper device can be adapted to various length specifications of thin-walled cylindrical parts for aerospace applications (workpiece 9, such as...). Figure 12 As shown), this effectively improves the versatility and compatibility of the equipment. The gripper assembly 5 provides a supporting clamping action on the support groove 91a of the tooling assembly 91 from both ends of the workpiece 9 (as shown). Figure 13 As shown in the diagram, this avoids the radial clamping force generated by the traditional grippers directly clamping the outer wall of the thin-walled cylinder, thus eliminating the risk of the thin-walled cylindrical part being flattened and deformed from the clamping method. The gripper assembly 5 can also move along the Z-axis with the slide ram 2 to achieve stable lifting and handling of the workpiece 9, providing a structural basis for the force-controlled servo clamping function.

[0044] The ram 2 is fixedly installed on the ram moving plate 21, which is set on the crossbeam frame 7 and can move back and forth in the horizontal direction. Figure 2 As shown. A first drive motor 21a is mounted on the sliding plate 21. A rack 71 is fixedly mounted horizontally on the crossbeam 7. A first gear 21b is mounted on the output shaft of the first drive motor 21a. The first gear 21b meshes with the rack 71 for transmission. Figure 3 As shown. The sliding ram moving plate 21 is driven by the meshing of the first drive motor 21a, the first gear 21b and the rack 71 on the crossbeam frame 7, and can move back and forth in the horizontal direction, so that the gripper assembly 5 can obtain a large range of horizontal displacement capabilities, thereby expanding the working coverage of the gripper and facilitating the transfer of workpiece 9 between multiple workstations.

[0045] The slide plate 21 is also equipped with a second drive motor 21c and a third guide rail 21d. A second gear 81 is provided on the output shaft of the second drive motor 21c. A rack portion 22 is provided on the slide 2 in the vertical direction. The second gear 81 meshes with the rack portion 22 to drive the slide 2 to move vertically along the third guide rail 21d. Figure 4 and Figure 5 As shown, the slide ram 2 is driven by the meshing of the second drive motor 21c, the second gear 81, and the vertical rack portion 22 on the slide ram 2, and guided by the third guide rail 21d. It can precisely rise and fall vertically, ensuring the smoothness and positioning accuracy of the workpiece 9 during loading and unloading. The horizontal movement and vertical lifting are independently controlled by the first drive motor 21a and the second drive motor 21c, respectively. The movements of the two axes are not coupled, allowing the gripper assembly 5 to flexibly adjust to the target gripping position according to the spatial position of the workpiece 9. Furthermore, the combination of gear and rack transmission and guide rail guidance ensures the transmission rigidity and straightness of the gripper assembly 5 during movement, preventing the influence of skewness or vibration on the detection accuracy of the sensor 64a, thus providing a reliable structural foundation for the stable implementation of force-controlled clamping.

[0046] The gripper assembly 5 is equipped with a lead screw 55 arranged along the moving direction of the moving end gripper 52. A handwheel 55a is provided at one end of the lead screw 55. The handwheel 55a drives the lead screw 55 to rotate, thereby driving the moving end gripper 52 to move along the first guide rail 54. Figure 8 As shown. Operators can manually adjust the position without additional tools. The operation is simple and the adjustment process is continuous and controllable, allowing for precise setting of the position of the moving end gripper 52 according to the actual length of the workpiece 9. The moving end gripper 52 is equipped with a guide rail brake seat 52a. After the moving end gripper 52 moves to the predetermined position, it is locked and fixed to the first guide rail 54 by the guide rail brake seat 52a. This locking structure reliably maintains the position of the moving end gripper 52 after adjustment, preventing accidental displacement of the moving end gripper 52 due to vibration or external force during clamping, and ensuring that the distance between the two grippers remains stable during clamping and handling.

[0047] The stationary end gripper 51 and the moving end gripper 52 each include a servo motor 61, a reducer 62 connected to the servo motor 61, a bidirectional threaded screw 63 connected to the reducer 62 and driven to rotate by the servo motor 61, and at least two support gripper assemblies 64, such as... Figure 9 As shown. The support claw assembly 64 is a nut seat that is threadedly engaged with the bidirectional threaded screw 63. The nut seat is slidably mounted on the second guide rail 65. When the bidirectional threaded screw 63 rotates, it drives the two support claw assemblies 64 to move towards or away from each other along the second guide rail 65 to achieve clamping or releasing of the workpiece 9.

[0048] The servo motor 61 drives the bidirectional threaded screw 63 to rotate via the reducer 62, causing the two support claw assemblies 64 to move synchronously towards or away from each other along the second guide rail 65, achieving the centering, clamping, and releasing of the workpiece 9. The bidirectional threaded screw 63 ensures that the displacement of the two support claw assemblies 64 is equal, ensuring that the axial position of the workpiece 9 does not deviate during clamping, effectively improving the repeatability of the clamping positioning. Compared with traditional pneumatic or hydraulic grippers, the drive method of the servo motor 61 and the reducer 62 can precisely control the feed amount of the support claw assembly 64 according to the diameter change of the workpiece 9, avoiding excessive or insufficient clamping force caused by the fluctuation of the outer diameter tolerance of the workpiece 9, and providing a controllable power basis for the safe clamping of thin-walled cylindrical parts. The support claw assembly 64 is mounted on the second guide rail 65 and slides along it. The second guide rail 65 constrains the movement direction of the support claw assembly 64, ensuring the linearity and stability of the clamping action and reducing the additional torque caused to the workpiece 9 by the movement deviation.

[0049] like Figure 14 As shown, a force sensor 64a is installed on the support claw assembly 64. The force sensor 64a is used to contact the workpiece 9 during clamping and generate radial clamping force. This signal can be fed back to the control system in real time, so that the drive amount of the servo motor 61 can be dynamically adjusted according to the feedback of the force sensor 64a, realizing closed-loop control of the clamping force. Even if there is a large tolerance in the outer diameter of the workpiece 9, the movement of the support claw assembly 64 can still be adaptively adjusted according to the actual contact state, ensuring that the tightness of each clamping is consistent and effectively preventing the thin-walled cylindrical parts from deforming due to excessive clamping force. The support claw assembly 64 is provided with a protrusion 64h, and the two ends of the workpiece 9 are tooling assemblies 91. The tooling assemblies 91 are provided with support grooves 91a. During clamping, the protrusion 64h is radially inserted into the support groove 91a along the direction of the second guide rail 65. This concave-convex mating structure (see also...) Figure 13 , Figure 14 This concentrates the clamping force onto the tooling assembly 91 rather than the thin-walled cylinder itself, further eliminating the deformation risk caused by the clamping force being directly applied to the thin-walled surface, while ensuring the axial and circumferential positioning reliability of the workpiece 9 in the clamping state.

[0050] like Figure 11As shown, the support claw assembly 64 includes a support claw 64b and a moving plate 64c. The support claw 64b has several slotted holes 64d and is bolted to the moving plate 64c through the slotted holes 64d. The slotted holes 64d allow the installation position of the support claw 64b relative to the moving plate 64c to be adjustable within a certain range, thereby allowing the initial distance between the two support claws 64b to be adjusted according to the diameter of the workpiece 9. This enables the same claw to adapt to thin-walled cylindrical parts of aerospace with different radial dimensions, further improving the compatibility of the equipment. The bottom surface of the moving plate 64c is provided with a locking plate 64e, which has locking holes. Locking pins 64g are provided in the locking holes to lock the sides of the support claw 64b. This locking structure adds lateral positioning constraint on the basis of the bolted connection of the slotted holes 64d, effectively preventing the support claw 64b from slipping or deflecting along the direction of the slotted holes 64d during clamping, significantly improving the installation rigidity and position retention accuracy of the support claw 64b. The diameter adaptation adjustment achieved by the waist hole 64d and the fastening and locking achieved by the locking pin 64g are combined to enable the support claw 64b to meet the clamping requirements of different workpiece diameters while maintaining a stable and reliable working state under high clamping force conditions, avoiding clamping offset or failure due to loose connection.

[0051] In terms of control, when the protrusion 64h of the support claw assembly 64 approaches the support groove 91a, the control unit of this force-controlled servo gripper first drives the support claw assembly 64 to feed rapidly in position mode. When the force sensor 64a detects the change in radial clamping force caused by contact, it switches to torque mode and gradually applies the target clamping force. After lifting the workpiece 9, the control unit continuously monitors the fluctuation of the radial clamping force measured by the force sensor 64a. When the fluctuation exceeds a preset threshold, it determines that the workpiece 9 has abnormal vibration and performs clamping force compensation to suppress the vibration. Through the above control strategy, the gripper achieves a smooth transition and dynamic stability throughout the entire process from approaching, contacting, clamping, and transporting the workpiece 9, effectively ensuring the clamping safety and reliability of aerospace thin-walled cylindrical parts in automated handling.

[0052] Example 2: The difference between this embodiment and Embodiment 1 is that one end of the lead screw 55 is driven by a rotary drive motor, which drives the lead screw 55 to rotate so as to drive the moving end gripper 52 to move along the first guide rail 54 (e.g., Figure 15 As shown), the position of the moving end gripper 52 is automatically adjusted; the guide rail brake seat 52a is an electronically controlled brake seat (as shown). Figure 10 As shown, the moving end gripper 52 moves to a predetermined position and is locked in place by electronic control. In this embodiment, the combination of automatic drive and electronic locking eliminates the need for manual intervention in adjusting the position of the moving end gripper 52. The control unit can directly control the adjustment process based on the length parameters of the workpiece 9, making the adjustment fast and precise. This is especially suitable for automated production lines where workpiece specifications change frequently.

[0053] In this embodiment, the servo gripper control unit integrates information such as the workpiece's geometric parameters, material properties, and slide motion planning. It can control the movement of the gripper assembly along the X, Y, and Z axes, the radial feed of the support gripper assembly 64, and the torque output of the servo motor. The control unit is connected to the first drive motor 21a, the second drive motor 21c, the first servo motor 41, the rotary drive motor 56, the two servo motors 61, the force sensor 64a, the position sensor, and the electronically controlled guide rail brake seat 52a via an industrial bus. Based on the workpiece parameters and sensor feedback, it performs closed-loop control of the displacement of each axis and the gripping torque.

[0054] Step 1: Obtain workpiece parameters and reference pose Input the following parameters of workpiece 9 to the control unit (pre-measured by the measuring device): cylinder length L (i.e., the axial distance between the support grooves 91a on the two end tooling assemblies 91), cylinder outer diameter D, and material density ρ. The geometric center coordinates of the workpiece in space (X... w Y w Z w Given the current orientation of the workpiece axis (horizontally placed), the vertical height H of the workpiece axis can be determined from the known geometric relationships. a =Z w The support groove 91a is designed to be located on the horizontal plane of the axis, therefore the center height of the groove is H. a Position sensors are installed at the same positions on each of the support claws 64b. Step 2: Automatic matching of the span of the moving end gripper The control unit calculates the required movement of the moving end gripper 52 along the first guide rail 54 based on the length L: △X = |L - X0|, where X0 is the current distance between the stationary gripper 51 and the moving gripper 52. The control unit drives the lead screw 55 by controlling the rotary drive motor 56, causing the moving gripper to move △X and lock the guide rail brake seat 52a after it reaches its position. At this time, the distance between the two grippers is precisely matched with the distance between the support grooves 91a at both ends.

[0055] Step 3: Align the vertical Z-axis With the support groove located on the horizontal plane where the workpiece axis is located as a constraint, calculate the movement of the gripper assembly 5 on the Z-axis: ΔZ = |H a -Z g |, where Z g The height of the current reference point for the gripper assembly is given. The slide block 2 moves ΔZ along the Z-axis so that the protrusion 64h of the support claw assembly 64 on the stationary and moving ends of the gripper is aligned with the corresponding support groove 91a in the height direction.

[0056] Step 4: The support claw 64b extends into the support groove. Through steps 2 and 3, the protrusions on each support claw 64b are aligned with the corresponding support grooves in the X-axis and Z-axis directions. At this point, the current spatial coordinates of the two support claw assemblies 64b on the same side are obtained, denoted as (x1, y1, z1) and (x2, y2, z2), and the symmetry center position y of the two support claws 64b in the Y-direction is calculated. o = (y1+y2) / 2, and compare this center value with the reference coordinate Y of the workpiece axis on the Y-axis. w Compare. Control the entire gripper assembly to translate along the Y-axis, so that y o With Y w Precise alignment is achieved, completing the centering of the support claw 64b in the Y-axis direction. After centering, the control unit drives the servo motor 61, which in turn drives the bidirectional threaded screw 63 to rotate via the reducer 62, causing the two support claws 64b to move synchronously towards each other along the second guide rail 65. The protrusion 64h is then smoothly inserted radially into the support groove 91a of the tooling assembly 91. Furthermore, for cases where the workpiece is tilted at an angle in the horizontal plane, the control unit can drive the first servo motor 41 to rotate the reducer bracket 31 around the vertical axis a. This, combined with the horizontal displacement of the sliding ram plate 21, achieves the rotational movement of the gripper assembly 5, adjusting the posture of the support claw assembly 64 to perfectly match the angle of the support groove 91a of the tooling assembly 91 at the end of the workpiece 9. This angle correction function directly compensates for the inward or outward placement deviations of the workpiece caused by the multi-machine tool layout, ensuring that the axial posture of the workpiece 9 after being gripped meets the indexing accuracy requirements of the fourth-axis servo rotary table of the downstream machine tool. This ensures that the tooling at the end of the workpiece can precisely align with the zero-point positioning device of the rotary table, completing the clamping and positioning.

[0057] Step 5: Contact sensing and torque mode clamping When the protrusion just enters the sidewall of the support groove, an initial contact force is generated in the horizontal direction, and the force sensor 64a detects a sudden change in the radial force signal. The control unit recognizes this contact signal and immediately switches the servo motor from position mode to torque mode.

[0058] Calculate the target radial clamping force based on the horizontal anti-slip requirements. The maximum horizontal acceleration during handling is a. h Take the anti-slip safety factor S h =2.0 (set according to requirements), required horizontal static friction force for a single claw: ; m is the total mass of the workpiece, n is the total number of 64b support claws, and a h This is the maximum acceleration of the conveying equipment (slide) when it moves horizontally. It comes from the system's motion planning instructions and is a known set value. When the control unit plans the motion of slide 2, it generates a trajectory curve (commonly such as a trapezoidal velocity curve or an S-curve). This curve clearly defines the parameters of the acceleration, constant speed, and deceleration segments.

[0059] Corresponding radial clamping force to the target: ; The static friction coefficient is The horizontal static friction required for a single claw. Measurements can be taken directly during the prototype stage using a simple inclined plane method or traction method. The servo motor is then closed-loop loaded to F. target The force sensor continuously feeds back the actual radial clamping force to ensure stable positive pressure.

[0060] Step 6: Vibration monitoring and active suppression during handling During the movement of the workpiece 9 driven by the slide ram 2, the control unit collects the radial clamping force of the force sensor 64a in real time and performs spectrum analysis on the signal. When a low-frequency oscillation component exceeding the preset background noise level is detected in the signal (for example, a significant peak appears in the 1~10Hz frequency band), the control unit determines that it is a horizontal oscillation caused by the movement of the workpiece 9.

[0061] At this point, the control unit takes one or both of the following measures based on the amplitude and frequency of the oscillation component: First, it adjusts the motion parameters, appropriately reducing the acceleration amplitude during the acceleration or deceleration phase (e.g., reducing the acceleration to 60%~80% of its original value) to reduce the dynamic excitation energy on workpiece 9. After adjusting the motion parameters, the control unit continues to monitor the spectral changes of the force signal. If the oscillation amplitude decays to below the safety threshold within a set time, the suppression is considered effective, and the current motion parameters are maintained.

[0062] Then, dynamic clamping force active compensation is performed. If the oscillation amplitude still does not effectively decrease after the first-level suppression measures are implemented, or if the oscillation amplitude is close to the critical value that endangers the safety of the workpiece, the control unit activates the second-level suppression. The control unit generates a dynamic compensation force command with opposite phase based on the dynamic fluctuation component of the force sensor 64a signal (i.e., the difference between the real-time signal and the static component corresponding to the target clamping force). Specifically, the control unit uses a proportional-derivative (PD) control law to calculate the compensation amount. ; ΔF(t) is the instantaneous deviation between the force sensor's measured value and the target clamping force, K p and K d These are the proportional gain and the derivative gain, respectively. This compensation is added in real time to the original torque command of the servo motor 61, causing the contact stiffness between the gripper assembly 5 and the tooling assembly 91 to change dynamically, thereby generating an active damping effect and absorbing the swing energy. In engineering implementation, K p and K dThe value of K is tuned using the Ziegler-Nichols critical scaling method combined with manual fine-tuning. Specifically, K is... d Set it to zero, and gradually increase K starting from a small value. p The response of the force sensor 64a to a step torque command is observed until the system output exhibits a continuous oscillation with constant amplitude, and the critical gain K at this point is recorded. max and oscillation period T u Press K p =0.8×K max K d =0.075×K max ×T u Calculate the initial parameters, then apply these parameters to the actual clamping system. Make small manual adjustments based on the measured response curve of the force sensor 64a. If the response is too slow, increase K appropriately. p If overshoot or oscillation is significant, increase K appropriately. d The system is repeatedly adjusted alternately until a good balance is achieved between rapid response and oscillation suppression. The two measures can be executed sequentially or in parallel depending on the severity of the oscillation amplitude. When the control unit determines that the oscillation amplitude exceeds a high-risk threshold, both measures are triggered simultaneously to achieve the fastest possible suppression.

[0063] Step 7: Offline identification of system damping ratio and adaptive calibration of basic clamping force The control unit considers the gripper assembly 5 and the workpiece 9 as an equivalent mass-spring-damping system. In this system model, the mass m of the workpiece 9 is the equivalent mass, the contact elasticity between the protrusion 64h and the support groove 91a and the structural stiffness of the gripper assembly 5 are the equivalent spring stiffness, and the friction and material damping inside the system are the equivalent damping.

[0064] During the intermittent periods of the handling tasks (e.g., the waiting period after the handling of a single workpiece), the control unit retrieves the radial clamping force fluctuation data recorded by the force sensor 64a during the previous handling process. When the system is subjected to known disturbances such as acceleration or deceleration of the slide 2, the signal from the force sensor 64a will exhibit a damped oscillation pattern. The control unit calculates the system's damping ratio ζ by extracting the ratio of adjacent peak values ​​of the oscillation waveform and using the logarithmic decay method. ; Among them, A i and A i+1 This represents the peak amplitude of two consecutive oscillation cycles. When the identified damping ratio ζ is lower than the preset stability threshold ζ... t When this occurs, it indicates that the system is in an underdamped state, which is detrimental to handling stability. At this time, the control unit records this state and automatically applies the target radial clamping force F calculated in step 5 to the next batch or the next clamping of workpieces of the same specification. targetMultiply by a correction factor greater than 1 (e.g., 1.1 to 1.3 times) to moderately increase the set value of the basic clamping force. Within the actual operating parameter range of this gripper system (normal pressure, surface roughness Ra ≤ 1.6 μm between the support claw 64b and the tooling component, and dry friction lubrication), the equivalent damping coefficient of the contact interface increases with increasing normal pressure, as verified by the prototype step response experiment. Within this specific parameter range, experimental data show that the increase in damping effect statistically significantly exceeds the increase in equivalent contact stiffness; therefore, the system damping ratio ζ increases monotonically with increasing clamping force. It should be noted that this conclusion is based on experimental results under specific operating conditions of this system, and its universality is limited by the above parameter range. Furthermore, the logarithmic decay method used in this embodiment is only applicable to underdamped systems (0 < ζ < 0.5). When the identified damping ratio ζ ≥ 0.5, the accuracy of this method decreases significantly, and it is no longer applicable to this control strategy.

[0065] The correction coefficient λ is determined as follows: The damping ratio deviation Δζ = ζ t -ζ (the difference between the threshold and the measured value) is used as input, and the value of λ is determined according to the following grading scheme: when Δζ ≤ 0.05, it indicates that the system is only slightly underdamped, and λ = 1.05 is taken; when 0.05 < Δζ ≤ 0.15, λ = 1.15 is taken; when Δζ > 0.15, λ = 1.25 is taken. At the same time, an upper limit of λ is set to 1.30 to prevent excessive clamping force from damaging the workpiece or tooling components. Specific values ​​can be adjusted according to the measured response under different working conditions. The preset stability threshold ζ t =0.3 is an empirical value pre-calibrated based on the structural dynamic characteristics of this gripper system. The determination of this value is based on the following: During the prototype debugging phase, the damping ratio of the system under different clamping forces was measured through step response experiments. Combined with the maximum allowable vibration amplitude of the thin-walled cylindrical component during handling, it was determined that when the damping ratio is below 0.3, the system is in an underdamped state, requiring more than three oscillation cycles to converge after a disturbance. The cumulative displacement during this period may exceed the allowable positioning deviation range of the workpiece. Therefore, 0.3 is set as the threshold for triggering the correction of the basic clamping force to ensure that the system always maintains an engineering-acceptable damping level. This value can be adjusted according to different actual environments.

[0066] This embodiment constructs a complete intelligent control chain of "geometric adaptation - force-position hybrid clamping - active vibration suppression" through steps 1 to 7. Step 5 is the first priority hard constraint, requiring the establishment of a closed loop for the target clamping force before the slide moves; otherwise, subsequent steps will not be triggered, ensuring the workpiece is not moved in an unclamped state from the outset. During transport, step 6 incorporates a two-level suppression strategy: firstly, it prioritizes adjusting the slide motion parameters (reducing acceleration amplitude) to mitigate external excitation; this is the primary first-line measure. If the oscillation does not decay, it initiates secondary dynamic force compensation (PD control), superimposing a reverse compensation force in real time to generate an active damping effect. Step 7, as a bottom-level, comprehensive adjustment, identifies the system damping ratio and actively modulates the contact stiffness. Its function is not to directly respond to instantaneous fluctuations, but rather to correct the clamping force benchmark of step 5 and change the inherent characteristics of the system, providing a more stable dynamic basis for the rapid compensation in step 6. The three aspects are implemented in a hierarchical manner: prerequisite protection → source reduction → rapid damping → stiffness self-tuning. This avoids over-reliance on a single method and achieves comprehensive control from the excitation source and transient response to the inherent stability of the system. This significantly improves the clamping safety, dimensional adaptability and vibration resistance of aerospace thin-walled cylindrical parts in automated handling.

[0067] The embodiments and / or implementation methods described above are merely preferred embodiments and / or implementation methods for implementing the technology of the present invention, and are not intended to limit the implementation methods of the technology of the present invention in any way. Any person skilled in the art may make some modifications to other equivalent embodiments without departing from the scope of the technical means disclosed in the content of the present invention, but these should still be regarded as the technology or embodiments that are substantially the same as the present invention. This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A force-controlled servo gripper for thin-walled cylindrical parts in aerospace applications, characterized in that, include: The top of the mounting plate (1) is used to fix it to the slide (2); The worm gear reducer (3) has its outer casing fixedly connected to the bottom of the upper mounting plate (1); The reducer bracket (31) is connected to the inner ring of the worm gear reducer (3) and can rotate around the vertical axis a under the drive of the first servo motor (41); The gripper assembly (5) is installed below the reducer bracket (31) and is used to grip the workpiece (9). The gripper assembly (5) includes a stationary gripper (51) and a moving gripper (52). The stationary gripper (51) is fixedly connected to one side of the bottom of the reducer bracket (31). The moving gripper (52) is mounted on the slider of the first guide rail (54) via a mounting plate (53) and can move relative to the stationary gripper (51) along the first guide rail (54) to accommodate workpieces (9) of different lengths.

2. The force-controlled servo gripper for thin-walled cylindrical parts in aerospace as described in claim 1, characterized in that, The slide (2) is fixedly installed on the slide moving plate (21), the slide moving plate (21) is set on the crossbeam frame (7) and can move back and forth in the horizontal direction; the slide moving plate (21) is provided with a first drive motor (21a), the crossbeam frame (7) is fixedly provided with a rack (71) in the horizontal direction, the output shaft of the first drive motor (21a) is provided with a first gear (21b), and the first gear (21b) meshes with the rack (71) for transmission; The sliding plate (21) is provided with a second drive motor (21c) and a third guide rail (21d). A second gear (81) is provided on the output shaft of the second drive motor (21c). A rack (22) is provided on the sliding plate (2) in the vertical direction. The second gear (81) meshes with the rack (22) to drive the sliding plate (2) to move vertically along the third guide rail (21d).

3. The force-controlled servo gripper for thin-walled cylindrical parts in aerospace as described in claim 1, characterized in that, The gripper assembly (5) is equipped with a lead screw (55) arranged along the moving direction of the moving end gripper (52). The lead screw (55) can rotate to drive the moving end gripper (52) to move along the first guide rail (54). The moving end gripper (52) is provided with a guide rail brake seat (52a). After the moving end gripper (52) moves to the predetermined position, it is locked and fixed to the first guide rail (54) by the guide rail brake seat (52a).

4. The force-controlled servo gripper for thin-walled cylindrical parts in aerospace as described in claim 2, characterized in that, The stationary end gripper (51) and the moving end gripper (52) each include: Servo motor (61); The speed reducer (62) is connected to the servo motor (61); A bidirectional threaded lead screw (63) is connected to the reducer (62) and is driven to rotate by the servo motor (61); At least two support claw assemblies (64) are nut seats that are threadedly engaged with the bidirectional threaded screw (63). The nut seats are slidably mounted on the second guide rail (65). When the bidirectional threaded screw (63) rotates, it drives the support claw assemblies (64) to move towards or away from each other along the second guide rail (65) to achieve clamping or releasing of the workpiece (9).

5. The force-controlled servo gripper for thin-walled cylindrical parts in aerospace as described in claim 4, characterized in that, A force sensor (64a) is installed on the support claw assembly (64). The force sensor (64a) is used to contact the workpiece (9) and generate radial clamping force during the clamping process. The support claw assembly (64) is provided with a protrusion (64h). The two ends of the workpiece (9) are tooling assemblies (91). The tooling assemblies (91) are provided with support grooves (91a).

6. The force-controlled servo gripper for thin-walled cylindrical parts in aerospace as described in claim 4, characterized in that, The support claw assembly (64) includes a support claw (64b) and a movable plate (64c). The support claw (64b) is provided with a number of waist holes (64d), and is bolted to the movable plate (64c) through the waist holes (64d). The bottom surface of the movable plate (64c) is provided with a locking plate (64e), and the locking plate (64e) is provided with a locking hole. A locking pin (64g) is provided in the locking hole to lock the side of the support claw (64b).

7. The force-controlled servo gripper for thin-walled cylindrical parts in aerospace as described in claim 5, characterized in that, It also includes a control unit, which is configured to: The amount of movement of the moving end gripper (52) along the first guide rail (54) is determined according to the length of the workpiece (9), so that the distance between the two end grippers matches the distance between the support grooves (91a) at both ends of the workpiece (9). The spatial height position of the axis of the workpiece (9) is determined according to the diameter of the workpiece (9), and the vertical movement of the gripper assembly (5) is determined by the constraint that the support groove (91a) is located on the horizontal plane of the axis, so that the protrusion (64h) of each support gripper assembly (64) is aligned with the corresponding support groove (91a) in the height direction. Based on the diameter of the workpiece (9) and the position of the support groove (91a) relative to the axis, determine the radial movement of each support claw assembly (64) along the second guide rail (65) so that the protrusion (64h) can be inserted into the support groove (91a) radially. Based on the spatial reference position and axis height of the workpiece (9), determine the amount of horizontal movement of the gripper assembly (5) and move the gripper assembly (5) to the gripping position. Based on the weight of the workpiece (9) and the static friction coefficient between the support claw (64b) and the tooling assembly (91), the target value of the radial clamping force required during the handling process is calculated. During the clamping process, the output torque of the servo motor (61) is controlled in a closed loop based on the actual radial clamping force signal measured by the force sensor (64a) so that the actual radial clamping force reaches the target value.

8. The force-controlled servo gripper for thin-walled cylindrical parts in aerospace as described in claim 7, characterized in that, The control unit is also configured to: When the protrusion (64h) of the support claw assembly (64) approaches the support groove (91a), the support claw assembly (64) is first driven to feed rapidly in position mode; When the force sensor (64a) detects the change in radial clamping force caused by contact, it switches to torque mode and gradually applies the target radial clamping force. After the workpiece is lifted, the fluctuation of the radial clamping force measured by the force sensor (64a) is continuously monitored. When the fluctuation exceeds the preset threshold, it is determined that the workpiece is abnormally shaking, and clamping force compensation is performed to suppress the shaking.

9. The force-controlled servo gripper for thin-walled cylindrical parts in aerospace as described in claim 8, characterized in that, The control unit is also configured to: During the process of the slide block (2) driving the workpiece (9) to move, the radial clamping force signal of the force sensor (64a) is collected in real time, and the signal is subjected to spectrum analysis. When a low-frequency oscillation component exceeding the preset background noise level is detected in the signal, it is determined to be a horizontal swing caused by the movement of the workpiece (9), and the motion parameters of the slide (2) and / or the clamping force of the servo motor (61) are adjusted accordingly to prevent the workpiece from being damaged due to increased shaking.

10. The force-controlled servo gripper for thin-walled cylindrical parts in aerospace as described in claim 8, characterized in that, The control unit is also configured to: The gripper assembly (5) and the workpiece (9) are considered as an equivalent mass-spring-damping system, and the current damping ratio of the system is identified during non-handling periods based on the historical fluctuation signals recorded by the force sensor during previous handling processes; When the identified damping ratio is lower than the preset stability threshold, the basic clamping force setting value of the servo motor (61) is adjusted in the next batch or the next clamping to change the stiffness of the equivalent system, thereby optimizing the dynamic stability of the subsequent handling process.

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