A dual-rotary force control ultrasonic impact strengthening device and method

Abstract

This invention relates to the field of metal surface processing technology, specifically disclosing a dual-rotation force-controlled ultrasonic impact strengthening device and method. The device includes a frame, a lifting and rotating mechanism, a specimen translation and rotation mechanism, an impact gun, and a specimen fixing seat. The lifting and rotating mechanism includes a lifting component and a first rotary driver. The lifting component drives the impact gun to rise and fall, and the first rotary driver drives the impact gun to rotate around a horizontal axis. The specimen translation and rotation mechanism includes a planar displacement component and a second rotary driver. The planar displacement component drives the specimen fixing seat to move horizontally, and the second rotary driver drives the specimen fixing seat to rotate around a vertical axis. The method includes acquiring the target strengthening path and discretizing it into process points, driving each mechanism to make the impact gun reach the target posture, acquiring the actual contact force fed back by the force sensor and driving the lifting component in a closed loop for micro-displacement compensation, and triggering impact output when the force condition is met. This invention achieves dual-rotation coordination and force-controlled closed loop, ensuring positional accuracy and data traceability.

Description

Technical Field

[0001] This invention relates to the field of metal surface processing technology, specifically to a dual-rotation force-controlled ultrasonic impact strengthening device and method. Background Technology

[0002] Ultrasonic impact strengthening technology uses a high-frequency impact needle to repeatedly impact the metal surface, causing plastic deformation in the near-surface layer and forming a beneficial residual compressive stress layer, which can effectively improve the fatigue strength of welded joints and metal structures. This technology has been applied to the strengthening treatment of weld toes, weld transition zones, notch roots, and specific areas of standard specimens, showing promising application prospects in aerospace, automotive, railway, and bridge structures. The effectiveness of ultrasonic impact strengthening is influenced by multiple parameters, including static pressure, impact direction, moving speed, and the number of effective impacts. The optimal selection of different process parameters has a significant impact on the strengthening of material properties.

[0003] Existing ultrasonic impact strengthening devices are mainly divided into two categories: handheld and CNC. Handheld operation relies on the operator to control the gun's posture and downward pressure, making it difficult to maintain consistent impact conditions when the weld direction changes or when the fixture obstructs the weld. As for CNC devices, existing CNC strengthening devices can achieve planar movement, constant load, or swing angle adjustment, while robotic strengthening devices can also perform path tracking.

[0004] However, the strengthening of flat welded parts and standard specimens faces a common problem: when the weld direction changes, the specimen clamping orientation is adjusted, or local areas are blocked by the fixture, the existing device cannot simultaneously ensure the target posture of the impact gun, the stable contact force, and the millimeter-level consistency between the actual impact position and the preset path. This results in significant fluctuations in the strengthening effect between different areas, and it is impossible to link and trace the actual execution data with the preset process parameters point by point. This limits the consistency and repeatability of ultrasonic impact strengthening technology in complex weld directions and batch standardized specimen processing. Summary of the Invention

[0005] To address the technical problems in the prior art, the present invention provides a dual-rotation force-controlled ultrasonic impact strengthening device and method, aiming to solve the problem that limits the consistency and repeatability of ultrasonic impact strengthening technology in complex weld seam orientation and batch standardized specimen processing.

[0006] The technical solution of the present invention is as follows: A dual-rotation force-controlled ultrasonic impact strengthening device includes a frame, a lifting and rotating mechanism, a specimen translation and rotation mechanism, an impact gun, and a specimen fixing seat, wherein: The lifting and rotating mechanism includes a lifting assembly and a first rotary drive. The lifting assembly is located on the top of the frame and connected to the impact gun, and is used to drive the impact gun to move in the vertical direction. The first rotary drive is connected between the lifting assembly and the impact gun, and is used to drive the impact gun to rotate around the horizontal axis to change the impact direction of the impact gun. The specimen translation and rotation mechanism includes a planar displacement component and a second rotary driver. The planar displacement component is located on the top of the frame and connected to the specimen fixing seat, and is used to drive the specimen fixing seat to move in the horizontal plane. The second rotary driver is connected between the planar displacement component and the specimen fixing seat, and is used to drive the specimen fixing seat to rotate around the vertical axis to change the orientation of the specimen.

[0007] Optionally, the lifting assembly includes a column, a slide, and a first driving member, wherein: The column is fixedly installed on the top of the frame, and a limiting slide rail is vertically provided on one side of the specimen fixing seat; The slide block is longitudinally slidably mounted on the limiting slide rail, and the impact gun is mounted on the slide block via the first rotary driver; The first driving component is located at the top of the column and is connected to the slide block drive to drive the slide block to slide back and forth along the limiting slide rail.

[0008] Optionally, the planar displacement assembly includes a guide rail assembly and a second drive element, wherein: The guide rail assembly is horizontally mounted on the top of the frame, and the specimen fixing seat is slidably mounted on the guide rail assembly; The second driving component is driven to the specimen fixing seat and is used to drive the specimen fixing seat to slide back and forth along the guide rail assembly.

[0009] Optionally, the guide rail assembly includes a first guide rail, a second guide rail, and a third drive member, wherein: The first guide rail is horizontally positioned at the top of the frame; The second guide rail is horizontally mounted on the top of the frame and perpendicular to the first guide rail. The second guide rail is slidably mounted on the first guide rail and can slide back and forth along the first guide rail. The specimen fixing seat is slidably mounted on the second guide rail and can reciprocate along the second guide rail; The third driving component is driven to connect with the second guide rail and is used to drive the second guide rail to slide back and forth along the first guide rail.

[0010] Optionally, the specimen holder includes a clamping base, a clamping block, and a fourth driving member, wherein: The clamping seat is mounted on the planar displacement assembly via a second rotary driver, and a clamping groove is provided on the top of the clamping seat; The clamping block is slidably disposed in the clamping groove for pressing and fixing the specimen; The fourth driving member is located at one end of the clamping seat and is connected to the clamping block drive, and is used to drive the clamping block to slide along the clamping groove to clamp or release the specimen.

[0011] Optionally, a dual-rotation force-controlled ultrasonic impact enhancement device may also include a force sensor; The force sensor is located on the force transmission path between the specimen fixing base and the second rotary drive, and is used to detect the actual contact force of the impact gun on the specimen.

[0012] The present invention also provides a dual-rotation force-controlled ultrasonic shock enhancement method, wherein the dual-rotation force-controlled ultrasonic shock enhancement device described above, the enhancement method includes: Obtain the target reinforcement path and discretize the target reinforcement path into several process points. Each process point is associated with at least target position information, target attitude information and target contact force information. Based on the target position information and target posture information of the current process point, the target height of the lifting component, the target rotation angle of the first rotary driver, the target plane position of the planar displacement component, and the target rotation angle of the second rotary driver are determined respectively, and the mechanisms are driven to move in coordination so that the ultrasonic impact gun reaches the target position and target posture corresponding to the current process point. The actual contact force fed back by the force sensor is obtained, and the deviation between the actual contact force and the target contact force information is used as feedback to drive the lifting component in a closed loop to perform micro-displacement compensation until the actual contact force meets the preset force tolerance. When the actual contact force meets the preset force condition, the ultrasonic impact gun is triggered to perform impact output at the current process point.

[0013] Optionally, discretizing the target enhancement path into several process points specifically includes: Extract the path tangent vector and surface normal vector of each process point based on the geometric information of the target reinforcement path; The path tangent vector is used to determine the impact direction in the target attitude information, and the surface normal vector is used to determine the impact tilt angle in the target attitude information; The spacing between adjacent process points is determined based on the geometric information of the target reinforcement path, and the spacing is inversely correlated with the curvature of the target reinforcement path.

[0014] Optionally, determining the target height of the lifting assembly, the target rotation angle of the first rotary drive, the target planar position of the planar displacement assembly, and the target rotation angle of the second rotary drive based on the target position information and target attitude information of the current process point specifically includes: Based on the target position information of the current process point, determine the target height of the lifting component and the target planar position of the planar displacement component; Based on the path tangent vector and surface normal vector of the current process point, and combined with the current rotation angle of the second rotary drive, calculate the target impact direction of the current process point in the device coordinate system; The impact axis direction of the ultrasonic impact gun when it is in a preset zero position is obtained, and the impact axis direction is compared with the target impact direction to calculate the target rotation angle of the first rotary driver.

[0015] Optionally, the closed-loop drive of the lifting assembly for micro-displacement compensation specifically includes: The actual contact force fed back by the force sensor is obtained, and the force deviation between the actual contact force and the target contact force information is calculated. Based on the force deviation, the micro-displacement compensation amount of the lifting component is calculated according to the proportional-integral control law; The lifting component is driven to move according to the micro-displacement compensation amount until the force deviation meets the preset force tolerance.

[0016] Compared with the prior art, the dual-rotation force-controlled ultrasonic impact enhancement device and method provided by the present invention have the following beneficial effects: (1) By setting up a lifting and rotating mechanism and a specimen translation and rotating mechanism, the ultrasonic impact gun has the freedom to rotate around the horizontal axis, and the specimen fixing seat has the freedom to move in the horizontal plane and rotate around the vertical axis. This forms a mechanical structure with dual rotation coordination between the impact gun and the specimen. Thus, under different weld directions, specimen clamping positions or partial obstruction conditions, the impact gun can reach the target position and target posture through the coordinated adjustment of the dual rotation angles, effectively improving the device's adaptability to complex working conditions.

[0017] (2) By placing the force sensor on the force transmission path between the specimen fixing seat and the second rotary drive, the actual contact force of the impact gun acting on the specimen is acquired in real time and used as closed-loop feedback. Before the impact output, the actual contact force is adjusted to the preset force tolerance range through the micro-displacement compensation of the lifting component, thereby avoiding contact force fluctuations caused by clamping errors, posture adjustments or local height changes of the specimen, and ensuring the consistency of impact conditions at each process point.

[0018] (3) By discretizing the target reinforcement path into process points with target position information, target attitude information and target contact force information, and associating each process point with path tangent vector and surface normal vector, a data basis is provided for the solution of dual rotation angles; at the same time, the geometric information of the target reinforcement path is used to determine the spacing between adjacent process points, so that the point cloud is automatically densified in areas with large corners or curvatures, further ensuring the positional consistency between the actual impact position and the preset path.

[0019] (4) The micro-displacement compensation of the lifting component is calculated based on the force deviation according to the proportional integral control law, and the lifting component is continuously driven to move until the force deviation meets the preset force tolerance, forming a closed-loop adjustment mechanism for contact force; at the same time, the impact output is triggered only after the force condition is met, so that the impact of each process point is established on the premise of force stability, effectively eliminating the invalid impact caused by the failure of contact force, and improving the controllability of the strengthening process and the consistency of process data. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a dual-rotation force-controlled ultrasonic impact strengthening device according to the present invention; Figure 2 This is a schematic diagram of the lifting and rotating mechanism of a dual-rotation force-controlled ultrasonic impact strengthening device according to the present invention; Figure 3 This is a schematic diagram of the specimen translation and rotation mechanism of a dual-rotation force-controlled ultrasonic impact strengthening device according to the present invention; Figure 4 This is a schematic diagram of the specimen fixing seat structure of the dual-rotation force-controlled ultrasonic impact strengthening device of the present invention; Figure 5 This is a flowchart illustrating the steps of a dual-rotation force-controlled ultrasonic impact enhancement method according to the present invention. Figure 6 This is a control logic block diagram of a dual-rotation force-controlled ultrasonic impact strengthening method according to the present invention.

[0021] In the diagram: 1. Frame; 2. Lifting and rotating mechanism; 21. Lifting assembly; 211. Column; 212. Slide; 213. First driving component; 2111. Limiting slide rail; 22. First rotary driver; 3. Specimen translation and rotation mechanism; 31. Planar displacement assembly; 311. Guide rail assembly; 3111. First guide rail; 3112. Second guide rail; 3113. Third driving component; 312. Second driving component; 32. Second rotary driver; 4. Impact gun; 5. Specimen fixing seat; 501. Clamping groove; 51. Clamping seat; 52. Clamping block; 53. Fourth driving component; 6. Force sensor. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0024] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0026] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0028] Please see Figures 1-4 The present invention provides a dual-rotation force-controlled ultrasonic impact strengthening device, including a frame 1, a lifting and rotating mechanism 2, a specimen translation and rotation mechanism 3, an impact gun 4, and a specimen fixing seat 5.

[0029] like Figures 1-3 As shown, the lifting and rotating mechanism 2 includes a lifting assembly 21 and a first rotary driver 22. The lifting assembly 21 is located on the top of the frame 1 and is connected to the impact gun 4, used to drive the impact gun 4 to move vertically. The first rotary driver 22 is connected between the lifting assembly 21 and the impact gun 4, used to drive the impact gun 4 to rotate around the horizontal axis to change the impact direction of the impact gun 4. The specimen translation and rotating mechanism 3 includes a planar displacement assembly 31 and a second rotary driver 32. The planar displacement assembly 31 is located on the top of the frame 1 and is connected to the specimen fixing seat 5, used to drive the specimen fixing seat 5 to move in the horizontal plane. The second rotary driver 32 is connected between the planar displacement assembly 31 and the specimen fixing seat 5, used to drive the specimen fixing seat 5 to rotate around the vertical axis to change the orientation of the specimen.

[0030] Specifically, the lifting and rotating mechanism 2 and the specimen translation and rotating mechanism 3 together form a dual-rotation coordinated mechanical structure; the lifting assembly 21 drives the impact gun 4 to move vertically, realizing the feed and retraction of the impact gun 4 in the height direction; the first rotary driver 22 drives the impact gun 4 to rotate around the horizontal axis, so that the impact pin of the impact gun 4 can impact the specimen surface at different angles to adapt to the impact direction requirements of different strengthening areas such as weld toe, weld transition zone and notch root; the planar displacement assembly 31 drives the specimen fixing seat 5 to move in the horizontal plane, realizing the X and Y direction positioning of the specimen in the horizontal plane; the second rotary driver 32 drives the specimen fixing seat 5 to rotate around the vertical axis, so that... The specimen fixed on the specimen holder 5 can be positioned in the horizontal plane. When the weld direction on the specimen changes, or when a certain area of ​​the specimen is blocked by the clamp, preventing the impact gun 4 from approaching in the target posture, the specimen can be rotated by the second rotary driver 32 to rotate the area to be strengthened to a position that is easy for the impact gun 4 to approach. At the same time, the pitch angle of the impact gun 4 can be adjusted by the first rotary driver 22 so that the impact pin is always aligned with the area to be strengthened in the preset impact direction. The above-mentioned dual-rotation coordination mechanism enables the same equipment to adapt to flat welds with different orientations, plate welded parts with different clamping postures, and standard specimens of different specifications, effectively improving the adaptability of the device to complex working conditions.

[0031] In some embodiments, such as Figure 2 As shown, the lifting assembly 21 includes a column 211, a slide 212, and a first driving member 213. The column 211 is fixedly installed on the top of the frame 1, and a limiting slide rail 2111 is vertically provided on one side corresponding to the specimen fixing seat 5. The slide 212 is longitudinally slidably installed on the limiting slide rail 2111, and the impact gun 4 is installed on the slide 212 through the first rotary driver 22. The first driving member 213 is located on the top of the column 211 and is drivenly connected to the slide 212 to drive the slide 212 to slide back and forth along the limiting slide rail 2111.

[0032] Specifically, the column 211 is fixed to the top of the frame 1, providing a stable support base for the lifting assembly 21; the limiting slide rail 2111 is vertically set on the side of the column 211 facing the specimen fixing seat 5, constraining the sliding direction of the slide 212 to ensure that the slide 212 moves only in the vertical direction without swaying; the impact gun 4 is mounted on the slide 212 via the first rotary drive 22, that is, the slide 212 serves as the mounting base for the first rotary drive 22, and the first rotary drive 22 rises and falls synchronously with the slide 212; the first driving component 213 is fixed to the top of the column 211, and its power output end is connected to the slide 211. The first driving component 213 drives the slide block 212 to slide up and down along the limiting slide rail 2111, thereby realizing the vertical feeding and retraction of the impact gun 4. Through the cooperation between the column 211 and the slide block 212, the vertical movement of the impact gun 4 during the impact process has high straightness and repeatability, which is beneficial to the accurate execution of micro-displacement compensation in the subsequent force control closed-loop adjustment. The setting of the limiting slide rail 2111 also ensures that the impact gun 4 will not be deflected due to gravity or impact reaction force during the lifting and lowering process, thereby ensuring that the impact needle can carry out impact in a stable vertical position at each process point.

[0033] In some embodiments, such as Figure 3 As shown, the planar displacement component 31 includes a guide rail component 311 and a second driving component 312. The guide rail component 311 is horizontally disposed on the top of the frame 1, and the specimen fixing seat 5 is slidably disposed on the guide rail component 311. The second driving component 312 is drivenly connected to the specimen fixing seat 5 and is used to drive the specimen fixing seat 5 to slide back and forth along the guide rail component 311.

[0034] Specifically, the guide rail assembly 311 is horizontally mounted on the top of the frame 1 to provide horizontal guidance for the specimen fixing seat 5; the specimen fixing seat 5 is slidably mounted on the guide rail assembly 311, and the second driving member 312 is mounted on the guide rail assembly 311 and drivenly connected to the specimen fixing seat 5. The specimen fixing seat 5 is driven by the second driving member 312 to slide back and forth along the guide rail assembly 311, thereby realizing the translational positioning of the specimen in the horizontal plane; through this setting, the position of the specimen in the horizontal plane can be adjusted by the second driving member 312, providing translational freedom for each process point on the specimen fixing seat 5 to reach the working area of ​​the impact gun 4 in sequence, so that the impact gun 4 can carry out point-by-point strengthening at different positions on the surface of the specimen.

[0035] In some embodiments, such as Figure 3As shown, the guide rail assembly 311 includes a first guide rail 3111, a second guide rail 3112, and a third drive member 3113. The first guide rail 3111 is horizontally disposed on the top of the frame 1; the second guide rail 3112 is horizontally disposed on the top of the frame 1 and perpendicular to the first guide rail 3111. The second guide rail 3112 is slidably disposed on the first guide rail 3111 and can reciprocate along the first guide rail 3111; the specimen fixing seat 5 is slidably disposed on the second guide rail 3112 and can reciprocate along the second guide rail 3112; the third drive member 3113 is drivenly connected to the second guide rail 3112 and is used to drive the second guide rail 3112 to reciprocate along the first guide rail 3111.

[0036] Specifically, the first guide rail 3111 is horizontally fixed to the top of the frame 1, and the second guide rail 3112 is perpendicular to the first guide rail 3111 and slidably mounted on the first guide rail 3111, forming an XY orthogonal planar motion structure; the third driving member 3113 drives the second guide rail 3112 to slide back and forth along the first guide rail 3111, realizing displacement in the X direction; the specimen fixing seat 5 is slidably mounted on the second guide rail 3112 and is driven by the second driving member 312 to slide back and forth along the second guide rail 3112, realizing displacement in the Y direction; the superposition of the above X and Y direction movements allows any process point on the specimen fixing seat 5 to reach any planar position within the working range of the impact gun 4; through the perpendicular orthogonal layout of the first guide rail 3111 and the second guide rail 3112, the motion trajectory of the specimen fixing seat 5 in the horizontal plane is precisely controllable, and the displacement in both directions can be independently calculated and driven according to the planar coordinates of the process point, thus providing an execution basis for planar positioning in dual rotational coordinate registration.

[0037] In some embodiments, such as Figure 4 As shown, the specimen fixing seat 5 includes a clamping seat 51, a clamping block 52, and a fourth driving member 53. The clamping seat 51 is mounted on the planar displacement assembly 31 via a second rotary driver 32. A clamping groove 501 is provided on the top of the clamping seat 51. The clamping block 52 is slidably disposed in the clamping groove 501 for pressing and fixing the specimen. The fourth driving member 53 is disposed at one end of the clamping seat 51 and is drivenly connected to the clamping block 52 for driving the clamping block 52 to slide along the clamping groove 501 to clamp or release the specimen.

[0038] Specifically, the clamping seat 51 is mounted on the planar displacement assembly 31 via the second rotary actuator 32. The clamping seat 51 serves two functions: as a platform supporting the specimen and as the driving object of the second rotary actuator 32 to change the orientation of the specimen. A clamping groove 501 is formed on the top of the clamping seat 51 to accommodate the specimen and provide clamping space. A clamping block 52 is slidably disposed within the clamping groove 501. A fourth driving member 53 is disposed at one end of the clamping seat 51 and is driven by the clamping block 52. The fourth driving member 53 drives the clamping block 52 to slide along the clamping groove 501 towards or away from the specimen. When the clamping block 52 slides towards the specimen, it presses against the specimen, fixing it within the clamping groove 501. When the clamping block 52 slides away from the specimen, it releases the specimen, facilitating its removal and replacement.

[0039] Through the cooperation of the clamping seat 51, the clamping block 52 and the fourth driving component 53, the specimen is quickly clamped and reliably fixed, ensuring that the specimen always maintains a fixed position relative to the clamping seat 51 during the rotation of the specimen fixing seat 5 with the second rotary driver 32 and the translation with the planar displacement component 31, avoiding the deviation of the position and posture of the process point from the preset value due to loose clamping; of course, this clamping method is not limited to this.

[0040] In some embodiments, such as Figure 3 As shown, a dual-rotation force-controlled ultrasonic impact strengthening device also includes a force sensor 6; the force sensor 6 is located on the force transmission path between the specimen fixing seat 5 and the second rotary driver 32, and is used to detect the actual contact force of the impact gun 4 acting on the specimen.

[0041] Specifically, the force sensor 6 is positioned on the force transmission path between the specimen holder 5 and the second rotary drive 32. When the impact pin of the impact gun 4 presses against the surface of the specimen, the contact force applied by the impact pin to the specimen is transmitted to the second rotary drive 32 via the specimen holder 5. The force sensor 6 is located in this force transmission path, thus enabling real-time detection of the actual contact force exerted by the impact gun 4 on the specimen. The force sensor 6 can be a single-axis force sensor, with its sensitive direction consistent with the loading direction of the impact gun 4, to accurately reflect the axial contact force. Alternatively, a multi-axis force sensor can be used to simultaneously detect tangential disturbances and axial forces, providing the controller with more comprehensive force information. The actual contact force signal detected by the force sensor 6 is sent to the internal control system in real time as feedback for force closed-loop control. By arranging the force sensor 6 on the force transmission path between the specimen holder 5 and the second rotary drive 32, the inertial force interference that might be introduced by placing the sensor on the impact gun 4 is avoided, making the measured contact force signal more realistically reflect the actual force between the impact pin and the specimen.

[0042] It should be understood that the internal control system is electrically connected to the lifting assembly 21, the first rotary drive 22, the planar displacement assembly 31, the second rotary drive 32, and the impact gun 4, respectively. It is used to receive the detection signal from the force sensor 6 and send drive commands to each mechanism to control the coordinated action of each mechanism. The control and drive methods here are all existing technologies and will not be described in detail here.

[0043] Please see Figures 5-6 The present invention also provides a dual-rotation force-controlled ultrasonic shock enhancement method, based on the aforementioned dual-rotation force-controlled ultrasonic shock enhancement device, wherein the enhancement method includes: S10: Obtain the target reinforcement path and discretize the target reinforcement path into several process points, each of which is associated with at least target position information, target attitude information and target contact force information.

[0044] In application, the target strengthening path originates from the weld centerline, weld toe line, or preset strengthening area of ​​the standard specimen, and can be imported through a two-dimensional design path, a three-dimensional model path, or a path after measurement correction. The process of discretizing the target strengthening path into several process points is essentially transforming a continuous geometric path into a series of discrete spatial coordinate points. Each process point serves as an independent execution unit, and subsequent position positioning, attitude adjustment, force control adjustment, and impact output are all executed one by one based on the process point. Each process point is associated with at least target position information, target attitude information, and target contact force information. These are used to determine the driving targets of the planar displacement component 31 and the lifting component 21, the rotation targets of the first rotary drive 22 and the second rotary drive 32, and the given values ​​for force closed-loop control, respectively. The above information together constitutes the process parameters required for the execution of subsequent steps.

[0045] In some embodiments, the target enhancement path is discretized into several process points, specifically including: The path tangent vector and surface normal vector of each process point are extracted based on the geometric information of the target reinforcement path; the path tangent vector is used to determine the impact direction in the target attitude information, and the surface normal vector is used to determine the impact tilt angle in the target attitude information; the spacing between adjacent process points is determined based on the geometric information of the target reinforcement path, and the spacing is inversely correlated with the curvature of the target reinforcement path.

[0046] In the application, the target enhancement path is a continuous spatial curve, and the geometric information of each discrete point on it is determined by the position coordinates of that point and its first derivative; for the i-th process point, its path tangent vector τ i By taking the first derivative and normalizing the position vector P(s) of the target enhancement path at that point, where s is the arc length parameter, we obtain: ; The tangent vector τ i Used to determine the direction of movement of the impact gun 4 along the path and the offset side of the impact gun 4 relative to the path in subsequent dual-rotation attitude calculations; the surface normal vector n of each process point i. i The preset impact angle of the impact pin relative to the specimen surface is determined by calculating the gradient of the specimen surface equation or by fitting the plane normal to the coordinates of multiple points in the path's vicinity. When the impact gun 4 operates in normal impact mode, the target impact direction is the opposite direction of the surface normal vector. When the impact gun 4 is required to form a preset angle β with the normal, the target impact direction is the opposite direction of the normal vector. i At that time, the target impact direction is determined by the tangent vector τ i Normal vector n i and tilt angle β i To be determined jointly.

[0047] The spacing between adjacent process points is adaptively determined based on the curvature of the target reinforcement path; curvature k i Defined as the rate of change of the tangent vector direction of the path at that point, a larger curvature indicates a greater degree of path curvature; to ensure sufficient path tracking accuracy in weld corners, weld toe transition zones, and areas near notches, the spacing between process points needs to be reduced in these areas; in straight areas, the spacing between process points is increased to improve path planning efficiency; as a specific adaptive discretization method, the arc length spacing Δs between adjacent process points is... i Determine using the following formula: = ; Where, Δs ref For reference spacing, it can be preset within the range of 0.05 to 1.00 mm according to the reinforcement bandwidth and process requirements; k i The curvature of the path at the current process point, in mm. -1 α is the curvature sensitivity coefficient, used to adjust the degree of influence of curvature on spacing. The value of α ranges from 1 to 10, and its selection is based on the following: when α is a smaller value, such as 1 to 3, the effect of curvature change on spacing is milder, suitable for paths with gentle curvature changes; when α is a larger value, such as 5 to 10, the effect of curvature change on spacing is more significant, suitable for weld paths with sharp corners or abrupt curvature changes. The specific value of α can be determined through process experiments. Discretization is performed on typical weld paths with different α values, and the maximum deviation between the discretized path and the original path is compared. The path with the maximum deviation not exceeding the position tolerance is selected. The minimum α value is preferably no greater than 1 mm; when k i When it approaches zero, i.e., a straight path, Δs i Approaching Δs ref When k i When the value is large, i.e., the turning path, Δs i Significantly reduced, process points are automatically encrypted.

[0048] Each process point is associated with a processing status identifier s during execution. i The status identifier includes at least the following types: Unprocessed, indicating that the process point has not yet been executed; Positioned, indicating that the position and attitude adjustment of the process point have been completed; Force Stable, indicating that the actual contact force of the process point has entered the force tolerance zone and reached the stabilization time requirement; Impacted, indicating that the impact output of the process point has been successfully executed; Pending Recalibration, indicating that the process point is waiting for recalibration because the position, attitude, or force deviation has not met the triggering conditions; Skipped, indicating that the process point is marked as skipped due to a hard fault or an unrecoverable deviation; Fault, indicating that a hard fault occurred during the execution of the process point; The control system updates the status based on the real-time status of the current process point during execution. i The value of .

[0049] After each process point is completed, the control system writes the actual execution data back to the corresponding attribute of that process point; among which, the actual tool center point position of the current process point is... The actual rotation angle of the second rotary drive 32 and the actual rotation angle of the first rotary drive 22 The angle change is calculated when selecting the equivalent angle combination for subsequent process points. and The baseline value, and the basis for re-registration during retries in the exception queue; the status of the impact output result is used to update the status flag s of this process point. i After the write-back is completed, the status flag s for this process point will be updated. i Updated to the corresponding final state, i.e. impacted, pending readjustment, skipped, or faulted, forming a complete process execution record with a one-to-one correspondence between planned and measured values. Among them, process data such as average contact force and force fluctuation range are used for offline quality traceability and process parameter optimization.

[0050] S20: Based on the target position information and target posture information of the current process point, determine the target height of the lifting component, the target rotation angle of the first rotary driver, the target plane position of the planar displacement component, and the target rotation angle of the second rotary driver, and drive each mechanism to move in coordination so that the ultrasonic impact gun reaches the target position and target posture corresponding to the current process point.

[0051] In application, based on the process point generated in S10, the control system calculates the target height of the lifting assembly 21, the target rotation angle of the first rotary driver 22, the target plane position of the planar displacement assembly 31, and the target rotation angle of the second rotary driver 32 according to the target position information and target attitude information of the current process point. The above four driving quantities correspond to the four degrees of freedom of motion of the device: the lifting assembly 21 provides vertical feed, the first rotary driver 22 provides attitude adjustment of the impact gun 4 around the horizontal axis, the planar displacement assembly 31 provides XY positioning in the horizontal plane, and the second rotary driver 32 provides orientation adjustment of the specimen around the vertical axis. The control system simultaneously sends the above four driving quantities to each actuator, so that each mechanism moves in coordination, and finally the impact pin of the impact gun 4 reaches the target position corresponding to the current process point, and at the same time aligns the axis of the impact pin with the target impact direction, thus completing the positioning and attitude preparation of the current process point.

[0052] In some embodiments, the target height of the lifting assembly, the target rotation angle of the first rotary drive, the target planar position of the planar displacement assembly, and the target rotation angle of the second rotary drive are determined based on the target position information and target attitude information of the current process point, specifically including: Based on the target position information of the current process point, determine the target height of the lifting component and the target plane position of the planar displacement component; based on the path tangent vector and surface normal vector of the current process point, and combined with the current rotation angle of the second rotary driver, calculate the target impact direction of the current process point in the device coordinate system; obtain the impact axis direction of the ultrasonic impact gun when it is in a preset zero position posture, and compare the impact axis direction with the target impact direction to calculate the target rotation angle of the first rotary driver.

[0053] In application, the target position of the i-th process point in the specimen coordinate system W is denoted as P. i W It is directly obtained from the discrete time of the target enhancement path. Based on the target position information P at the current process point... i W Based on the fixed transformation relationship T between the specimen coordinate system W and the device coordinate system D DW Calculate the target position P of the process point in the device coordinate system D. i D :

[0054] ; The target location P i D 3D coordinates (x) i D y i D , zi D The x and y values ​​of the planar displacement component 31 are respectively determined by the target plane position of the planar displacement component 31. i D and y i D The component; and the target height of the lifting assembly 21, i.e., z i D The component, denoted as P, represents the target plane position. XY,i That is, P XY,i = (x i D y i D Let the target height be denoted as z. i , i.e. z i =z i D : Based on the path tangent vector τ of the current process point i W and surface normal vector n i W First, by fixing the rotation transformation matrix R DW The two coordinates are transformed from the specimen coordinate system W to the reference direction of the device coordinate system D, and then rotated by the second rotary actuator 32 at an angle θ. s,i about the vertical axis a s Rotate to obtain the path tangent vector and surface normal vector of the current process point in the device coordinate system D: ; ; Among them, R DW The fixed rotational transformation matrix from the specimen coordinate system W to the device coordinate system D is obtained from the clamping datum calibration of the specimen fixing seat 5 and remains unchanged during the machining process; a s The direction of the rotation axis of the second rotary drive 32 is the vertical axis direction, R(a) s θ s ) is about the axis a s Rotation angle θ s The rotation matrix; through the above transformation, the path tangent vector and surface normal vector of the process point rotate synchronously with the rotation of the specimen in the horizontal plane.

[0055] Construct the lateral unit vector b i D : ; If the impact gun 4 is required to impact along the surface normal, then the target impact direction is: ; If the impact gun 4 is required to have a preset tilt angle β with the normal direction. i If there is an impact, the direction of the impact is: ; Where, η i Taking +1 or -1 indicates the direction in which the impact gun 4 is positioned, selected from both sides of the weld; β i The preset impact angle ranges from 0° to 30°, and is determined based on β. i At 0°, the impact gun 4 impacts along the surface normal, suitable for conventional weld toe strengthening; β i When the angle is 5° to 15°, the impact gun 4 is slightly tilted, which is suitable for the weld transition zone or for situations where interference between the impact pin and the base material needs to be avoided; β i When the impact gun is tilted at four angles between 15° and 30°, it is suitable for confined spaces or special weld configurations; β i The specific value is determined through process testing based on the specimen material, weld type, and strengthening process requirements; different β values ​​are applied to typical specimens. i Impact tests were conducted, and the optimal value was selected by comparing the depth of the reinforced residual compressive stress layer and the surface roughness. The target rotation angle of the second rotary actuator 32. The determination method is as follows: within the range of 0° to 360°, a certain step size is used, preferably 1° to 2°. The step size is selected based on the following criteria: a 1° step size can provide sufficient angular resolution to ensure attitude accuracy, while the calculation of 360 candidate values ​​can be completed in real time within the computing power of current industrial controllers; traversal For each candidate value, the corresponding target impact direction is calculated using the above formula. ( Select the target rotation angle of the first rotary drive 22 obtained in subsequent calculations. The candidate value that satisfies the preset attitude tolerance and has no interference between the impact gun 4 and the specimen and fixture is used as the target rotation angle of the second rotary drive 32.

[0056] Finally, the target rotation angle of the first rotary drive 22 is determined; the axial direction of the impact pin of the impact gun 4 when it is in the preset zero position is obtained. This direction is the inherent directional parameter determined during factory calibration or power-on zeroing of the impact gun 4; and the direction of impact with the target Projected onto the rotation axis a perpendicular to the first rotary drive 22 respectively g On the plane: ; ; Among them, a gThe direction of the rotation axis of the first rotary driver 22 is the horizontal axis direction; u0 is the direction of the zero-position impact axis of the impact gun 4 perpendicular to a. g The projected unit vector on the plane, u i The target impact direction is perpendicular to a. g Projected unit vector on the plane. Target rotation angle of the first rotary actuator 22. Calculate using the following formula:

[0057] ; Where atan2 is the arctangent function in the fourth quadrant, and its return value range is (-π, π]. This represents the cosine of the angle between two projection vectors. This represents the cross product of two projected vectors on the rotation axis a. g The ratio of the directional components determines the magnitude and direction of the rotation angle; the value calculated using this formula... That is, to make the actual impact axis of the impact gun 4 aligned with the target impact direction. The deviation between them satisfies the target rotation angle of the first rotary drive 22 required by the preset attitude tolerance; it should be noted that in the path discretization stage of S10, each process point has been associated with a path tangent vector τ. i W and surface normal vector n i W This step directly uses this related information for calculation; at the same time, due to the target rotation angle of the second rotary drive 32 and the target rotation angle of the first rotary drive 22 There is a coupling relationship between them. Changes will alter the target's impact direction. This will affect The calculation results are as follows; in actual solution, the two angles need to be solved together as a set of coupled variables, rather than independently.

[0058] After completing the above calculation of the dual rotation angles, it is also necessary to verify whether the positioning error between the actual tool center point position of the impact gun 4 and the current process point target position meets the preset position tolerance. Let the homogeneous coordinate of the process point in the specimen coordinate system W be P. i W The transformation from the zero position of the specimen to the coordinate system of the device is T. DS,0 The reference pose of the impact gun 4 is T. DG,0 (q xyz ), where q xyz This indicates the position of the impact gun 4 in the device coordinate system; the fixed offset of the impact pin tip in the impact gun coordinate system G is r. tip G Then the target position of the current process point in the device coordinate system D. for:

[0059] ; The actual position of the impact needle tip in the device coordinate system D for: ; Among them, (x) i y i , z i R(a) represents the actual position coordinates reached by the lifting assembly 21 and the planar displacement assembly 31 driving the impact gun 4. g , (a) is the axis of rotation about the first rotary drive 22. g Rotation angle The rotation matrix.

[0060] The positioning constraint requires that the Euclidean distance between the actual position of the impact needle tip and the target position of the current process point satisfy the following: ; in, This is to allow for a preset position tolerance. The actual impact axis direction of the impact gun 4 is:

[0061] ; The above positioning constraint formula defines the target rotation angle of the second rotary drive 32. and the target rotation angle of the first rotary drive 22 The position error and attitude error are both included in the calculation, and together they determine whether the actual position and impact direction of the impact needle tip meet the process requirements.

[0062] Regarding the preset position tolerance The method for determining the location tolerance should satisfy the error budget constraint: ; Where, σ cal σ is the standard deviation of the calibration error of the tool center point. reg σ represents the standard deviation of the registration error between the process point cloud and the device coordinate system. enc σ represents the standard deviation of the encoder feedback error for each axis. fixture This represents the standard deviation of the repeatability error in specimen clamping; simultaneously... The deviation must not exceed the maximum allowable deviation by the process; in this application, the preset position tolerance... The preferred tolerance is no greater than 1mm. This value is based on the following: this accuracy can be achieved through a combination of the repeatability of a commercially available high-precision ball screw (±0.005mm) and the resolution of an absolute encoder (≤0.001mm). Simultaneously, the 1mm tolerance provides ample budget space for the accumulation of path discrepancy errors, calibration errors, and registration errors. During equipment debugging, the total error budget must be verified using a laser displacement gauge or coordinate measuring machine. This value can only be applied after confirming that the actual total error is indeed less than 1mm.

[0063] S30: Obtain the actual contact force fed back by the force sensor, and use the deviation between the actual contact force and the target contact force information as feedback to drive the lifting assembly in a closed loop to perform micro-displacement compensation until the actual contact force meets the preset force tolerance.

[0064] In the application, after the impact gun 4 reaches the target position and orientation of the current process point, the impact pin of the impact gun 4 contacts the surface of the specimen, and the force sensor 6 begins to detect the actual contact force in real time. The control system acquires the actual contact force signal fed back by the force sensor 6 and calculates the deviation between it and the target contact force. Based on the direction and magnitude of this deviation, the control system drives the lifting assembly 21 in a closed loop to perform micro-displacement compensation—when the actual contact force is less than the target contact force, the lifting assembly 21 drives the impact gun 4 to move slightly downward to increase the contact force; when the actual contact force is greater than the target contact force, the lifting assembly 21 drives the impact gun 4 to move slightly upward to decrease the contact force. This micro-displacement compensation process continues until the actual contact force enters the preset force tolerance zone.

[0065] In some embodiments, the closed-loop drive of the lifting assembly performs micro-displacement compensation, specifically including: The actual contact force fed back by the force sensor is obtained, and the force deviation between the actual contact force and the target contact force information is calculated; based on the force deviation, the micro-displacement compensation amount of the lifting component is calculated according to the proportional-integral control law; the lifting component is driven to move according to the micro-displacement compensation amount until the force deviation meets the preset force tolerance.

[0066] In the application, after the impact gun 4 reaches the target position and orientation of the current process point, the impact pin of the impact gun 4 contacts the surface of the specimen, and the force sensor 6 begins to detect the actual contact force in real time. Because the impact pin applies a high-frequency impact to the specimen surface under ultrasonic vibration during the ultrasonic impact process, the original signal detected by the force sensor 6 contains a high-frequency impact component. If this high-frequency component is directly used for force closed-loop control, it will cause frequent shaking of the lifting assembly 21. Therefore, before calculating the force deviation, the original signal of the force sensor 6 is preprocessed. ; Where k is the control cycle number, Fraw (k) represents the initial output value of force sensor 6 in the kth control cycle, F offset For zero-point offset, data was collected under no-load conditions after the impact pin was removed from the specimen. LPF{ } represents the low-pass filtering operation, F f (k) represents the actual contact force in the kth control cycle; the cutoff frequency of the low-pass filter is preferably 10-50Hz, and its value is determined based on the following: the ultrasonic impact frequency is usually above 20kHz, and setting the cutoff frequency to 10-50Hz can effectively suppress high-frequency impact components while retaining the low-frequency envelope information of contact force changes; if the cutoff frequency is too low, i.e. less than 10Hz, the force control response speed is insufficient and the contact force overshoot increases; if the cutoff frequency is too high, i.e. greater than 50Hz, the high-frequency component suppression is insufficient and the lifting component 21 is prone to jitter; if a sliding mean filter is used, its window length corresponds to a time window of 10-50ms.

[0067] The target contact force at the current process point is denoted as F. tar,i Then the force deviation e in the kth control cycle F (k) is: ; When |e F (k) | Not greater than the preset force control dead zone ΔF dead When |e| indicates that the current actual contact force is within an acceptable range near the target contact force, no additional micro-feed is required in this cycle; F (k)|When the dead zone is exceeded, the micro-displacement compensation Δz(k) of the lifting component 21 is calculated according to the incremental proportional-integral control law: ; Among them, K p K is a proportionality coefficient, with a value ranging from 0.002 to 0.02 mm / N. This value is determined based on a comprehensive estimation of the contact stiffness of a typical metal specimen (approximately 10–100 N / mm) and the transmission ratio of the lifting assembly 21. p When the value is too large, i.e., greater than 0.02 mm / N, it is easy to cause oscillation in the force closed-loop system. p If the value is too small, i.e., less than 0.002 mm / N, the response speed will be insufficient; K i This is the integral coefficient, and its value ranges from 0.01 to 0.20 mm / (N). s), the value is determined based on: K i Used to eliminate steady-state error, its value is determined by the desired force error settling time. The settling time corresponding to the above range is approximately 0.2–1.0 s, which matches the force stability requirements of ultrasonic impact processes; T s To control the cycle, the corresponding closed-loop refresh frequency is 100–500 Hz, i.e., T s =1 / fs f s The closed-loop refresh rate is determined based on the following: 100Hz meets the basic requirements for force control response, 500Hz is the highest usable frequency for most industrial controllers, and frequencies higher than 500Hz place excessive demands on hardware with limited benefits; F (k-1) represents the force deviation from the previous control cycle; Δz max This is the maximum allowable micro-feed amount within a single control cycle, ranging from 0.005 to 0.05 mm. The value is determined by considering the Z-axis resolution of the lifting assembly 21, which is typically ≤0.001 mm, and the contact stiffness, which is approximately 10–100 N / mm. 0.005 mm corresponds to a force resolution of approximately 0.05–0.5 N, and 0.05 mm corresponds to a force resolution of approximately 0.5–5 N, which can cover the adjustment requirements of 50–200 N target contact force in typical ultrasonic impact processes. ,-Δz max ,Δz max} is the amplitude limiting function, which limits the output to [-Δz]. max ,Δz max Within the specified range, to prevent excessive single compensation from causing rigid collision between the impact pin and the specimen.

[0068] The meanings of the above-mentioned micro-displacement compensation amount Δz(k) are as follows: a positive value indicates that the lifting assembly 21 drives the impact gun 4 to feed downward slightly, so that the impact pin presses deeper against the surface of the specimen, thereby increasing the contact force; a negative value indicates that the lifting assembly 21 drives the impact gun 4 to retract upward slightly, so that the impact pin reduces the pressure on the surface of the specimen, thereby reducing the contact force; the target height command z of the lifting assembly 21 is... cmd (k) Updated using the following formula: ; Among them, z min and z max These represent the lower and upper boundaries of the axial position allowed at the current process point, respectively; meanwhile, the integral term saturates at the actuator, i.e. zcmd (k) reaches z min or z max The system freezes upon impact pause or when the force sensor 6 signal malfunctions to prevent integral saturation. This process is repeated within each control cycle until |e F (k)∣≤ΔF dead .

[0069] Regarding the systematic tuning method for control parameters, the above K p and K i The numerical range is not arbitrarily given, but is obtained through comprehensive tuning via the following experimental steps: First, conduct an unloaded noise test on the force sensor 6 to obtain the standard deviation σ of the background noise of the force signal. FForce control dead zone ΔF dead At least 3σ should be covered F The first step is to sum the sensor resolution margins; the second step is to conduct a contact stiffness step test, where the impact pin of the impact gun 4 approaches and contacts the specimen surface at a low speed of 0.1–1.0 mm / s, records the force response curve, and estimates the contact stiffness based on the slope of the force-displacement curve; the third step is to first set K... i =0, gradually increase K p Until the force closed-loop system exhibits continuous oscillation, the critical K is taken. p 30% to 60% of the value is used as K p The setpoint value; K p Choosing 30% to 60% of the critical value, rather than a higher value, is to ensure sufficient stability margin for the system while maintaining response speed, preventing system instability due to changes in equipment stiffness or differences in specimen materials; the fourth step is to maintain K... p Keep K unchanged and gradually increase it. i The force deviation is kept within the preset force tolerance zone of 0.2 to 1.0 s, and the maximum overshoot does not exceed 10% of the target contact force. The overshoot of no more than 10% is to prevent excessive impact force from causing excessive deformation or damage to the surface of the specimen.

[0070] Regarding the preset values ​​for force tolerance and settling time, the preferred value for force tolerance is max(0.05F). tar,i ,3σ F +Sensor resolution margin), its value is based on: 0.05 Ftar,i This ensures that the force tolerance changes proportionally with the target contact force, avoiding excessively lenient tolerance for small target forces or excessively stringent tolerance for large target forces; 3σ F It covers 99.7% of the no-load noise distribution, and together with the sensor resolution margin, ensures that the force tolerance is greater than the sensor's physical measurement limit. The force tolerance is typically ±5% to ±10% of the target contact force; the settling time, i.e., the time it takes for the actual contact force to continuously meet the requirements within the force tolerance band, ranges from 0.2 to 1.0 s, preferably 0.5 s. The value is determined based on the following: it should not be less than the maximum of three factors: 5 times the filter time constant, the minimum duration required for consecutive sampling points, and the time required to enter the tolerance band during a contact stiffness step test. The cutoff frequency of 10–50 Hz corresponds to τ. f =3.2~16ms, 5 times is 16~80ms, sampling frequency of 500Hz requires 0.2s for 100 consecutive points; 0.5s is the preferred value to ensure sufficient force stability judgment without excessively prolonging the process cycle.

[0071] Before the impact pin of the impact gun 4 contacts the surface of the specimen, the lifting assembly 21 drives the impact gun 4 to move towards the specimen at a low approach speed. The value of this speed is in the range of 0.1 to 1.0 mm / s. The basis for this value is that the speed needs to be low enough to ensure that the impact force overshoot does not exceed 10% of the target force when the impact pin contacts the surface of the specimen. This speed is determined by the response capability and sampling frequency of the force closed-loop control system. At the same time, it should not be too low to affect the process cycle. Within the range of 0.1 to 1.0 mm / s, the lower speed of 0.1 to 0.3 mm / s is suitable for thin plates or specimens with low rigidity, and the higher speed of 0.5 to 1.0 mm / s is suitable for thick plates or specimens with high rigidity. The specific value is determined by process tests based on the hardness, surface roughness and contact stiffness of the specimen material.

[0072] During the impact output process, the control system continuously monitors the actual contact force fed back by the force sensor 6. When the actual contact force continuously exceeds the preset force tolerance band for a duration of 50-200ms, the control system determines that the force state is abnormal, suspends the ultrasonic impact output, and enters the readjustment process. The time threshold is determined based on the following: the time window of 50-200ms needs to be greater than the response time of the force closed-loop adjustment, usually 50-100ms, to allow the system to recover on its own through closed-loop adjustment, while being less than the critical time that may cause a decrease in impact quality due to continuous force deviation. It is determined by process tests, and the typical preferred value is 100ms.

[0073] S40: The actual contact force meets the preset force condition, triggering the ultrasonic impact gun to perform impact output at the current process point.

[0074] In application, when the force closed-loop adjustment of S30 causes the actual contact force to enter the preset force tolerance zone and remain stable for a preset stabilization time (preferably 0.2–1.0 s), the specific value is determined based on the response characteristics of the force closed-loop adjustment and the process cycle requirements; the control system determines that the force condition of the current process point meets the preset force condition. At this time, the control system sends an impact trigger signal to the ultrasonic impact gun 4, starts the ultrasonic generator output, and the impact needle performs high-frequency impact strengthening on the surface of the specimen under the action of ultrasonic vibration; after the impact output continues for a preset time, determined by the ultrasonic impact time in the process parameters, it is usually 0.1–2.0 s, and the specific value is determined based on the material type, strengthening depth requirements, and process test results; the control system stops the ultrasonic output, the strengthening of the current process point is completed, and then enters the next process point, repeating S20 to S40, until all process points are completed.

[0075] When the target rotation angle θ of the second rotary drive 32 s,iWhen multiple candidate values ​​satisfy the preset attitude tolerance, the control system first uses hard constraints to screen and eliminate candidate angle combinations. The hard constraints include: any angle in the candidate angle combination exceeds the soft limit range of the corresponding rotary actuator; the envelope model of the impact gun 4 or specimen holder 5 under the candidate angle combination collides and interferes with the envelope model of the fixture, specimen, or frame 1, i.e., the digital envelope check fails; the actual position of the impact pin tip under the candidate angle combination exceeds the reachable working space in the device coordinate system D; the cumulative value of continuous rotation corresponding to the candidate angle combination exceeds the cable anti-tangling threshold; and the position error ep,i or attitude error e under the candidate angle combination... a,i Exceeding the corresponding preset tolerance or Attitude tolerance ε a The typical value range is 2° to 5°, and the basis for this value is as follows: the cone angle of the impact pin is usually 45° to 60°, and the deviation range of 2° to 5° can ensure that the change in the contact area between the impact pin and the surface of the specimen does not exceed 5% to 10%. At the same time, this accuracy can be achieved by commercially available high-precision angle encoders, whose resolution is usually ≤0.01°. The specific value is determined by process experiments based on the impact pin type, such as cone angle, tip radius and weld toe geometry, such as transition radius and weld toe angle. Any candidate angle combination that meets any of the above hard constraints is directly eliminated and does not enter the cost function calculation stage.

[0076] For the remaining candidate angle combinations, calculate the cost function J. i : ; Among them, e p e represents the position error under the current candidate angle combination. a This represents the attitude error under the current candidate angle combination. To preset the position tolerance, To preset the attitude tolerance, Δθ s The target rotation angle of the second rotary drive 32 in the current candidate angle combination is θ, which is the actual rotation angle θ of the second rotary drive 32 relative to the previous process point. s,i-1,act The shortest surrounding angle difference, Δθ g The target rotation angle of the first rotary drive 22 in the current candidate angle combination is θ relative to the actual rotation angle θ of the first rotary drive 22 at the previous process point. g,i-1,act The shortest surrounding angle difference, Θ s and Θ g These are the nominal rotation ranges of the second rotary drive 32 and the first rotary drive 22, respectively, preferably 360°. Δz is the change in height of the lifting assembly 21 relative to the actual height of the lifting assembly 21 at the previous process point under the current candidate angle combination. Z0 is the nominal stroke of the lifting assembly 21. clearAs a penalty term related to obstacle safety clearance, when the minimum safety clearance between the impact gun 4 or the specimen holder 5 and the obstacle under the candidate angle combination is less than a preset threshold, this term takes a larger positive value; otherwise, it takes zero. The typical value range and basis for each weight coefficient are as follows: w p =0.20~0.30, positional accuracy is the key indicator to ensure that the impact point does not deviate from the preset path, and has the highest weight among all items; w a =0.20~0.30, attitude accuracy directly affects the deviation between the impact direction and the surface normal, and is as important as position accuracy; w s =0.10~0.20, θ s The continuity of rotation affects the smoothness of specimen rotation and cable life, and its priority is slightly lower than position and attitude accuracy; g =0.15~0.25, θ g The continuity affects the smoothness of the rotation of the impact gun 4 and the cable life, because the cable of the impact gun 4 is more sensitive to torsion and has a slightly higher weight than θ. s ;w z =0.03~0.08, the height variation in the z-direction has a relatively small impact on process continuity, and therefore has a low weight; w c =0.08~0.15, the safety clearance plays a key role when approaching the interference region, but should not dominate the angle selection under normal operating conditions.

[0077] As a specific implementation method, a feasible initial weight set is w p =0.25、w a =0.25、w s =0.15、w g =0.20、w z =0.05、w c=0.10, the above weight coefficients reflect the priority of each optimization objective in the selection of the dual rotation angle combination: position accuracy and attitude accuracy have the highest weights, 0.25 each, reflecting the core process requirement of "ensuring the accuracy of the impact point position and direction"; angle continuity has the next highest weights, 0.15 and 0.20, used to suppress angle jumps between adjacent points and reduce frequent driver reversals and cable twisting; height change has the lowest weight, 0.05, indicating that height direction changes have the least impact on process quality; safety clearance has a weight of 0.10, which plays a constraining role when approaching the interference area; using this set of weights as the initial values, its rationality is verified by comparison during the prototype debugging stage: run the complete process on a typical weld path, and compare the execution results of the angle combination optimized by the cost function with those of the fixed angle scheme. The fixed angle scheme only uses the first candidate value that meets the attitude tolerance; if the average angle change between adjacent process points after optimization is reduced by more than 30% compared with the fixed angle scheme, and the increase in position error and attitude error does not exceed 10%, then the weight configuration is effective; otherwise, adjust the corresponding weights according to the deviation; increase w when the angle change is not significantly reduced. s and w g When the position or attitude error increases significantly, increase w. p and w a This verification was performed using 3-5 weld seams as samples. If this set of weights is used directly without verification, improper weight configuration may cause the cost function to be overly biased towards a certain optimization objective. For example, excessively pursuing angular continuity at the expense of positional accuracy could cause the impact point to deviate from the preset path beyond the positional tolerance ε. p This ultimately causes the impact zone to deviate from the weld toe, reducing the strengthening effect. The control system selected is J. i The combination of angles with the smallest value is taken as the optimal combination of double rotation angles for the current process point.

[0078] To prevent adjacent process points from frequently jumping between two sets of equivalent angle combinations, when the cost J of the current candidate angle combination... i If the cost reduction compared to the currently used consecutive candidate angle combinations is less than 10%–20%, no switching operation will be performed, and the currently used angle combination will continue to be used. The switching threshold is determined based on the following: a cost improvement of less than 10% is not cost-effective relative to the commutation wear of the driver and cables, while a cost improvement of more than 20% may result in excessive accumulation of position or attitude errors due to persisting with the suboptimal angle combination. The 10%–20% threshold range is an engineering experience value and can be fine-tuned during the equipment commissioning phase based on the actual processing cycle and cable torsional fatigue life. Switching to the new candidate angle combination is only permitted when the cost of the new candidate angle combination is reduced by more than the above threshold compared to the currently used angle combination, or when the currently used angle combination fails due to the triggering of hard constraints.

[0079] Before performing the strengthening process, a unified safety height benchmark needs to be established; with the vertical direction of the device coordinate system D as Z. D Axis, safety height z safe Defined as the safe retracted position of the impact pin of the impact gun 4 in its non-processing state, this position should ensure that the impact pin and any part of the impact gun 4 are higher than all obstacles in the current movement area. Safe height z safe The value is determined by the equipment's geometric parameters and error budget:

[0080] ; Among them, z obs,max The highest envelope of the fixture, specimen, and obstacles within the current motion region is defined in the device coordinate system D by the Z-axis. D To coordinate value; h tool δ is the axial dimension projection from the tip of the impact needle to the lowest interference point of the impact gun 4; cal For the tool center point calibration error; δ reg For the registration error between the process point cloud and the device coordinate system; δ follow h is the upper limit of servo following error. margin To provide an additional safety margin, the typical range is 5–10 mm. The basis for this margin is that it must be greater than the cumulative value of calibration error and registration error, usually 2–5 mm. At the same time, it leaves sufficient room for dynamic fluctuations during the movement of each axis, introduced by servo following error, usually 0.5–2 mm. This ensures that the impact gun 4 will not collide with obstacles under any unexpected movement deviation. As a specific implementation, the safe position of the impact pin is set to be 10–30 mm higher than the highest obstacle in the current movement area, while retaining the above-mentioned additional safety margin. The final value is determined during the equipment debugging stage through collision checks and no-load operation verification.

[0081] During the enhanced processing, the control system continuously monitors the operating status of the device and executes corresponding handling strategies based on the type of anomaly. Anomaly criteria are categorized into the following four types:

[0082] Positional anomaly: refers to a situation where, after the motion stabilizes, the Euclidean distance between the actual tool center point of the impact gun 4 and the target position of the current process point exceeds the preset position tolerance ε. p If the position deviation exceeds the set value of the driver, or the servo following error exceeds the set value of the driver, the control system first performs local fine-tuning in the XY and Z directions. If the position deviation still exceeds the limit after the second attempt, the angle encoder values ​​of the first rotary driver 22 and the second rotary driver 32 are reread and the forward kinematics are recalculated. If the position tolerance requirement still cannot be met, the control system drives the lifting assembly 21 to raise the impact gun 4 to a safe height z. safe Then, re-register the coordinates of the current local area or mark the process point as an anomaly.

[0083] Angle anomaly: This refers to a situation where the dual-rotation solution of the first rotary driver 22 or the second rotary driver 32 is infeasible, or the difference between the encoder measured angle and the target angle exceeds the preset attitude tolerance ε. a The system triggers a soft limit switch or the cumulative value of continuous rotation reaches the cable anti-tangling threshold. When an angle abnormality occurs, the control system calls the next set of dual rotation angle combinations from the equivalent angle candidate list; if no candidate angle is available, the lifting assembly 21 is driven to raise the impact gun 4 to a safe height z. safe After shifting to the intermediate obstacle avoidance posture, it approaches the current process point again.

[0084] Force anomaly: refers to force sensor 6 exceeding its range, disconnection or communication timeout, zero drift exceeding 3 times the standard deviation of no-load noise, abnormal force change rate, or the actual contact force failing to enter the preset force tolerance zone within the specified adjustment time; when force anomaly occurs, if the force is insufficient and no contact is detected, the control system continues to micro-feed along the current impact axis at a low speed, preferably 0.1 to 1.0 mm / s; if contact has been made but the force error continues to exceed the limit, proportional-integral force closed-loop adjustment continues to be executed; if the force exceeds the upper limit, the force change rate is abnormal, or the force sensor 6 malfunctions, the control system immediately stops the impact output, controls the lifting assembly 21 to drive the impact gun 4 back, and prohibits automatic increase of the target contact force.

[0085] Collision anomaly: This refers to a failure of the digital envelope check, i.e., interference occurs between the envelope model of the impact gun 4 or the specimen holder 5 and the obstacle envelope model, or the safety input signal is triggered. When a collision anomaly occurs, the control system immediately stops all motion outputs, prohibits impact outputs, and drives the lifting assembly 21 to raise the impact gun 4 to a safe height z. safe It will be restored after manual confirmation.

[0086] Of the four types of anomalies mentioned above, the recoverable types of position anomalies, angle anomalies, and force anomalies allow for automatic re-adjustment, and the re-adjustment mechanism is detailed above; force sensor 6 disconnection, collision anomaly, and servo hard fault are hard faults and will not enter the automatic retry process. The operator must stop the machine to confirm and troubleshoot the fault before processing can be resumed.

[0087] During the execution of each process point, the control system follows the sequence of "safe movement, double angle calculation, pose positioning, low-speed approach, force stabilization, gating judgment, impact, and recording". When a process point fails to meet the preset triggering conditions in the force stabilization or gating judgment stage, the control system enters the re-adjustment process.

[0088] Re-adjustment when position is not satisfied: The control system first performs local fine-tuning in the XY and Z directions; if the position deviation still exceeds the limit after the second attempt, the angle encoder values ​​of the first rotary driver 22 and the second rotary driver 32 are reread and the forward kinematics are recalculated; if it still fails, the lifting assembly 21 is controlled to raise the impact gun 4 to a safe height z. safe If necessary, re-register the coordinates of the current local area or mark the current process point as an anomaly point, and retry once the remaining process points of this path are completed.

[0089] When the attitude is not satisfied, the control system calls the next set of dual rotation angle combinations from the equivalent angle candidate list, which is the target rotation angle of the second rotary actuator 32. Target rotation angle of the first rotary drive 22 Alternative combinations; if no candidate angle is available, the drive lifting assembly 21 will raise the impact gun 4 to a safe height z. safe After shifting to the intermediate obstacle avoidance posture, it approaches the current process point again.

[0090] Rebalancing when force is insufficient: If the force is insufficient and no contact is detected, the control system continues to feed at a low speed along the current impact axis direction, preferably 0.1 to 1.0 mm / s; if contact has been made but the force error continues to exceed the limit, proportional-integral force closed-loop adjustment continues; if the force exceeds the upper limit, the force change rate is abnormal, or the force sensor 6 malfunctions, the control system immediately stops the impact output, controls the lifting assembly 21 to drive the impact gun 4 back, and prohibits the automatic increase of the target contact force.

[0091] Number of automatic retuning operations and parameter adjustments: N times of automatic retuning for each process point retry,max The upper limit is 2-3 times, based on the following: 2-3 retests can cover most occasional failures caused by temporary disturbances, such as vibration and signal noise, without significantly affecting the process cycle time. Exceeding this number indicates a systematic deviation at the process point, such as coordinate registration errors or abnormal path generation. Continuing automatic retries is not only difficult to recover from, but may also exacerbate equipment wear or cause collision risks, so manual intervention should be used. During each retest, the control system can reduce the low-speed approach speed of the impact gun 4 from 1.0 mm / s to 0.5 mm / s or 0.2 mm / s, and reduce the maximum micro-feed amount Δz per cycle, from a pre-verified parameter set. max For example, reducing the angle from 0.05mm to 0.02mm or 0.01mm, switching to the next candidate in the equivalent angle combination, or extending the force stabilization observation time from 0.5s to 1.0s, but the target contact force F tar,i The process validation scope must not be exceeded, and the proportionality coefficient K p and integral coefficient K iOnline unlimited self-increment is not allowed; the value of this restriction is based on the fact that the target contact force and control gain are both process-sensitive parameters. Temporary adjustments without process verification may change the impact strengthening effect or cause the force closed-loop system to become unstable. Therefore, only adjustments to motion parameters and equivalent angle combinations are allowed within a safe range. Motion parameters include speed, micro-feed amount, and settling time.

[0092] Distinguishing between recoverable failures and hard faults: Failures that can be safely corrected locally, such as force deviation exceeding limits or attitude deviation exceeding limits, will be retried immediately at the current process point; failures that require re-registration or will significantly disrupt the main path will be added to the exception queue, such as coordinate registration failure or position deviation that still does not meet the requirements after three attempts, and will be retried uniformly after the completion of this path segment; force sensor 6 disconnection, collision anomaly, and servo hard faults will not enter the automatic retry process and must be stopped for confirmation.

[0093] It should be understood that, regarding the control execution entity in each step of the above method, the control functions involved in S10 to S40, such as force signal acquisition and preprocessing, force deviation calculation, proportional-integral control law calculation, dual rotation angle collaborative solution, and generation and transmission of drive commands for each mechanism, are all executed by the control system. The control system is electrically connected to the lifting assembly 21, the first rotary drive 22, the planar displacement assembly 31, the second rotary drive 32, the force sensor 6, and the impact gun 4. The control system receives the actual contact force signal fed back by the force sensor 6, reads the angle encoder feedback values ​​of the first rotary drive 22 and the second rotary drive 32, as well as the position encoder feedback values ​​of the lifting assembly 21 and the planar displacement assembly 31, executes the calculations in the above steps, and sends the corresponding drive commands to the lifting assembly 21, the first rotary drive 22, the planar displacement assembly 31, and the second rotary drive 32 to control each mechanism to coordinate its actions according to the calculated drive amount; when the preset trigger condition in S40 is met, the control system sends an impact trigger signal to the impact gun 4 to start the ultrasonic output. The electrical connections and signal transmission methods between the control system and the aforementioned mechanisms are well-known technologies in the field and will not be described in detail here.

[0094] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A dual-rotation force-controlled ultrasonic impact enhancement device, characterized in that, It includes a frame (1), a lifting and rotating mechanism (2), a specimen translation and rotation mechanism (3), an impact gun (4), and a specimen fixing seat (5), wherein: The lifting and rotating mechanism (2) includes a lifting assembly (21) and a first rotary driver (22). The lifting assembly (21) is located on the top of the frame (1) and connected to the impact gun (4) for driving the impact gun (4) to move in the vertical direction. The first rotary driver (22) is connected between the lifting assembly (21) and the impact gun (4) for driving the impact gun (4) to rotate around the horizontal axis to change the impact direction of the impact gun (4). The specimen translation and rotation mechanism (3) includes a plane displacement component (31) and a second rotary driver (32). The plane displacement component (31) is located on the top of the frame (1) and connected to the specimen fixing seat (5) for driving the specimen fixing seat (5) to move in the horizontal plane. The second rotary driver (32) is connected between the plane displacement component (31) and the specimen fixing seat (5) for driving the specimen fixing seat (5) to rotate around the vertical axis to change the orientation of the specimen.

2. The dual-rotation force-controlled ultrasonic impact enhancement device according to claim 1, characterized in that, The lifting assembly (21) includes a column (211), a slide (212), and a first driving member (213), wherein: The column (211) is fixedly installed on the top of the frame (1), and a limiting slide rail (2111) is vertically provided on one side of the specimen fixing seat (5). The slide block (212) is longitudinally slidably mounted on the limiting slide rail (2111), and the impact gun (4) is mounted on the slide block (212) via the first rotary driver (22); The first driving member (213) is located on the top of the column (211) and is driven to connect with the slide (212) to drive the slide (212) to slide back and forth along the limiting slide rail (2111).

3. The dual-rotation force-controlled ultrasonic impact enhancement device according to claim 1, characterized in that, The planar displacement assembly (31) includes a guide rail assembly (311) and a second drive element (312), wherein: The guide rail assembly (311) is horizontally disposed on the top of the frame (1), and the specimen fixing seat (5) is slidably disposed on the guide rail assembly (311); The second driving member (312) is drivingly connected to the specimen fixing seat (5) and is used to drive the specimen fixing seat (5) to slide back and forth along the guide rail assembly (311).

4. The dual-rotation force-controlled ultrasonic impact enhancement device according to claim 3, characterized in that, The guide rail assembly (311) includes a first guide rail (3111), a second guide rail (3112), and a third drive member (3113), wherein: The first guide rail (3111) is horizontally positioned at the top of the frame (1); The second guide rail (3112) is horizontally disposed on the top of the frame (1) and perpendicular to the first guide rail (3111). The second guide rail (3112) is slidably disposed on the first guide rail (3111) and can slide back and forth along the first guide rail (3111). The specimen fixing seat (5) is slidably disposed on the second guide rail (3112) and can slide back and forth along the second guide rail (3112); The third driving member (3113) is driven to connect with the second guide rail (3112) and is used to drive the second guide rail (3112) to slide back and forth along the first guide rail (3111).

5. The dual-rotation force-controlled ultrasonic impact enhancement device according to claim 1, characterized in that, The specimen fixing seat (5) includes a clamping seat (51), a clamping block (52), and a fourth driving member (53), wherein: The clamping seat (51) is mounted on the planar displacement assembly (31) via the second rotary drive (32), and the top of the clamping seat (51) is provided with a clamping groove (501). The clamping block (52) is slidably disposed in the clamping groove (501) for pressing and fixing the specimen; The fourth driving member (53) is located at one end of the clamping seat (51) and is driven to connect with the clamping block (52), and is used to drive the clamping block (52) to slide along the clamping groove (501) to clamp or release the specimen.

6. The dual-rotation force-controlled ultrasonic impact enhancement device according to claim 1, characterized in that, It also includes a force sensor (6); The force sensor (6) is located on the force transmission path between the specimen fixing seat (5) and the second rotary drive (32) and is used to detect the actual contact force of the impact gun (4) on the specimen.

7. A dual-rotation force-controlled ultrasonic shock enhancement method, characterized in that, Based on the dual-rotation force-controlled ultrasonic impact strengthening device according to claim 6, the strengthening method includes: Obtain the target reinforcement path and discretize the target reinforcement path into several process points. Each process point is associated with at least target position information, target attitude information and target contact force information. Based on the target position information and target posture information of the current process point, the target height of the lifting component, the target rotation angle of the first rotary driver, the target plane position of the planar displacement component, and the target rotation angle of the second rotary driver are determined respectively, and the mechanisms are driven to move in coordination so that the ultrasonic impact gun reaches the target position and target posture corresponding to the current process point. The actual contact force fed back by the force sensor is obtained, and the deviation between the actual contact force and the target contact force information is used as feedback to drive the lifting component in a closed loop to perform micro-displacement compensation until the actual contact force meets the preset force tolerance. When the actual contact force meets the preset force condition, the ultrasonic impact gun is triggered to perform impact output at the current process point.

8. The dual-rotation force-controlled ultrasonic shock enhancement method according to claim 7, characterized in that, Discretizing the target enhancement path into several process points specifically includes: Extract the path tangent vector and surface normal vector of each process point based on the geometric information of the target reinforcement path; The path tangent vector is used to determine the impact direction in the target attitude information, and the surface normal vector is used to determine the impact tilt angle in the target attitude information; The spacing between adjacent process points is determined based on the geometric information of the target reinforcement path, and the spacing is inversely correlated with the curvature of the target reinforcement path.

9. The dual-rotation force-controlled ultrasonic shock enhancement method according to claim 8, characterized in that, The step of determining the target height of the lifting assembly, the target rotation angle of the first rotary drive, the target planar position of the planar displacement assembly, and the target rotation angle of the second rotary drive based on the target position information and target attitude information of the current process point specifically includes: Based on the target position information of the current process point, determine the target height of the lifting component and the target planar position of the planar displacement component; Based on the path tangent vector and surface normal vector of the current process point, and combined with the current rotation angle of the second rotary drive, calculate the target impact direction of the current process point in the device coordinate system; The impact axis direction of the ultrasonic impact gun when it is in a preset zero position is obtained, and the impact axis direction is compared with the target impact direction to calculate the target rotation angle of the first rotary driver.

10. The dual-rotation force-controlled ultrasonic shock enhancement method according to claim 7, characterized in that, The closed-loop drive for micro-displacement compensation of the lifting assembly specifically includes: The actual contact force fed back by the force sensor is obtained, and the force deviation between the actual contact force and the target contact force information is calculated. Based on the force deviation, the micro-displacement compensation amount of the lifting component is calculated according to the proportional-integral control law; The lifting component is driven to move according to the micro-displacement compensation amount until the force deviation meets the preset force tolerance.

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