Lever displacement amplification double-shaft complete decoupling rapid tool servo device and topological optimization method thereof

Abstract

The invention discloses a lever displacement amplification double-shaft complete decoupling rapid tool servo device and a topological optimization method thereof. The tool servo device comprises a base body, a double-shaft amplification driving module, a double-shaft decoupling module and a tool apron. The double-shaft amplification driving module comprises two single-shaft driving modules. The single-shaft driving module comprises a lever amplification structure and a piezoelectric stack. And the double-shaft decoupling module comprises two decoupling units. The decoupling unit comprises two sine type decoupling hinges which are in axial symmetry. The slender straight circular hinge connected with the lever amplification structure and the sine type decoupling hinge connected with the base body are arranged on the periphery of the tool apron, so that the driving displacement error caused by motion bending deformation is reduced, the displacement control precision of the tool apron in different directions is improved, and the influence of pretightening force on coupling disturbance is reduced to the maximum extent. Meanwhile, topological optimization is carried out on a connecting lever amplification structure, and the problem that dynamic performance and light weight are difficult to consider at the same time is solved.

Description

Technical Field

[0001] This invention belongs to the field of ultra-precision metal cutting technology, specifically relating to a topology optimization design and method for a lever displacement amplification dual-axis fully decoupled high-speed tool servo device. Background Technology

[0002] Optical microstructures, such as diffractive elements, artificial compound eyes, and two-dimensional gratings, have shown broad application prospects in optical imaging, photoelectric detection, and high-energy lasers due to their significant advantages in improving optical system performance, simplifying system design, and enhancing imaging quality. Despite these surface structures' numerous functional advantages, their highly complex structures and nanoscale precision requirements pose significant challenges to the fabrication process. Currently, commonly used technologies for manufacturing optical microstructures include high-energy beam processing, photolithography, special energy field processing, ultra-precision machining based on natural cutting tools, and nanoimprinting. In comparison, ultra-precision cutting technologies (such as diamond turning and milling) utilize the excellent properties of cutting tools to efficiently process components with ultra-smooth surfaces and complex structures. Therefore, they are considered a very promising and efficient method for manufacturing optical microstructures and are widely used in the production of optical components such as microgratings, microdiffractive elements, and microlens arrays.

[0003] In the field of diamond ultra-precision machining, Fast Tool Servo (FTS) systems have become a rapidly developing technology in the fabrication of optical microstructure surfaces in recent years due to their high machining performance, wide material applicability, low cost, and high flexibility in machining complex structures. FTS technology uses high-frequency driven tool dynamic modulation at the micro- and nano-scale, enabling the machining trajectory to precisely follow the geometry of complex surfaces, thus overcoming the limitations of traditional ultra-precision turning techniques. Currently, common FTS systems mainly employ single-axis drive methods, including piezoelectric stack drive, Lorentz electromagnetic force drive, and Maxwell electromagnetic force drive. Among these, piezoelectric drive is widely used in micro- and nano-precision machining due to its high force density and fast response. However, single-axis driven FTS systems have limitations when dealing with complex three-dimensional optical surfaces. Therefore, multi-axis tool servo technology has gradually become a research focus, and researchers both domestically and internationally are dedicated to developing dual-axis or more degrees of freedom FTS systems to improve the machining capabilities of complex surfaces.

[0004] In existing multi-axis FTS systems, piezoelectric stack actuation remains the most common approach, typically combined with uniaxial flexible hinge mechanisms to achieve high-precision motion control. However, the strain limitations of piezoelectric materials result in a short actuation stroke (generally between a few micrometers and tens of micrometers), which cannot meet the demands of large-scale dynamic machining. To extend the stroke of piezoelectric actuation, researchers have proposed multi-stage displacement amplification mechanisms using uniaxial flexible hinges, such as bridge structures, lever structures, and Scott–Russell structures. These solutions have effectively addressed the limited motion stroke problem to some extent. Summary of the Invention

[0005] The purpose of this invention is to provide a topology optimization design and method for a lever displacement amplification dual-axis fully decoupled fast tool servo device.

[0006] In a first aspect, the present invention provides a lever displacement amplification dual-axis fully decoupled rapid tool servo device, comprising a base, a dual-axis amplification drive module, a dual-axis decoupling module, and a tool holder. The dual-axis amplification drive module includes two orthogonally arranged single-axis drive modules. Each single-axis drive module includes a lever amplification structure and a piezoelectric stack. The lever amplification structure is configured to amplify the displacement output by the piezoelectric stack and transmit it to the tool holder.

[0007] The dual-axis decoupling module comprises two decoupling units. Each decoupling unit includes two spaced-apart and axisily symmetrical sinusoidal decoupling hinges. The sinusoidal decoupling hinges have a sinusoidal corrugated elastic sheet structure. The two decoupling units correspond to two single-axis drive modules, respectively. The corresponding decoupling units and single-axis drive modules are connected to a set of opposite sides of the tool holder. The sinusoidal flexible hinges in the two decoupling units cooperate to provide a mechanical basis for decoupling motion in two directions, ensuring that the tool can move independently and precisely in different axes.

[0008] Preferably, the single-axis drive module further includes a slender decoupling hinge. One end of the lever amplification structure is connected to the base via a flexible hinge. The slender decoupling hinge is connected to the other end of the lever amplification structure and to the tool holder. The slender decoupling hinge includes two parallel elastic connecting pieces.

[0009] Preferably, the lever amplification structure includes a lever body and a connecting fulcrum structure. The lever body and the connecting fulcrum structure are connected in an L-shape. The end of the connecting fulcrum structure facing away from the lever body is integrally connected to the base.

[0010] Preferably, the connecting fulcrum structure has a straight edge near the piezoelectric stack and an arc-shaped edge away from the piezoelectric stack, comprising a concave arc segment and a convex arc segment. The concave arc segment is connected to the substrate; the convex arc segment smoothly transitions to the side edge of the lever body.

[0011] Preferably, the front end of the lever body has a convex arc shape on the side opposite to the tool holder. The lever amplification structure has multiple hollow structures formed through topology optimization iteration. The positions of the hollow structures are offset from the support points of the piezoelectric stack.

[0012] Preferably, the piezoelectric stack abuts against the side of the lever amplification structure. The piezoelectric stack is preloaded via a straight-plate hinge preload mechanism.

[0013] Preferably, the substrate has a central receiving groove for accommodating the tool holder, the dual-axis amplification drive module, and the dual-axis decoupling module.

[0014] Preferably, the system also includes a mounting base and a displacement detection module. The mounting base is fixed to the base. The displacement detection module includes a positioning slot in the mounting base, two detection holes orthogonally arranged and connected to the positioning slot, and displacement sensors. The positioning slot is aligned with the tool holder; a positioning block located within the positioning slot is fixed to the back of the tool holder. The two displacement sensors are respectively mounted on the detection holes. The detection parts of the two displacement sensors face two orthogonal sides of the positioning block through the two detection holes.

[0015] Preferably, the mounting base has a clearance groove on its side facing the base. A support pad is provided on the bottom surface of the clearance groove. The support pad contacts the base and is fixed by bolts. The position of the support pad is offset from the dual-axis amplification drive module and the dual-axis decoupling module.

[0016] Secondly, the present invention provides a topology optimization method for optimizing the aforementioned lever displacement amplification dual-axis fully decoupled fast tool servo device.

[0017] The topology optimization method includes:

[0018] Construct the objective function The constraints are set, including constraints on output coupling coefficient, input coupling coefficient, displacement amplification ratio, input compliance, and element relative density.

[0019]

[0020] in, To optimize the set of design variables, Let be the relative density of the unit cells in the lever-guided topology, i = 1, 2, ..., n; and n be the number of topological partitioning units in the lever-guided topology. For the first The eigenvalues ​​corresponding to the first natural frequencies; As a weighting factor; , These are the actual output displacement and the target output displacement of the output port, respectively.

[0021] An analysis domain is established, encompassing the dual-axis amplification drive module and the area where the tool holder is located. This analysis domain is divided into a design domain corresponding to the lever-guided topology, a physical non-design domain corresponding to the tool holder, and an empty non-design domain. Two input ports are set in the design domain at the positions where the piezoelectric stacks apply thrust; two output ports are set in the physical non-design domain; each of the two input ports and two output ports is equipped with a virtual spring.

[0022] The design domain is iteratively optimized based on the objective function and constraints to obtain the optimized lever-guided topology.

[0023] Thirdly, the present invention provides a tool servo control method for driving the aforementioned tool servo device. The tool servo control method includes: during the machining process of a workpiece, driving a corresponding single-axis drive module according to the predetermined movement direction of the tool, causing the piezoelectric stack therein to generate a telescoping displacement, thereby causing the tool to move along the target direction. The displacement of the tool is acquired in real time through a dual-axis displacement detection module, and negative feedback adjustment is performed based on the detection results to correct the piezoelectric stack input signal of the relevant single-axis drive module until the tool reaches the desired position.

[0024] The present invention has the following beneficial effects.

[0025] 1. This invention uses a slender decoupling hinge in the lever guide topology, combined with a sinusoidal decoupling hinge set on the other side of the tool holder, to make eight hinges evenly connected around the tool holder, thereby reducing the driving displacement error caused by motion bending deformation, improving the displacement control accuracy of the tool holder in different directions, and minimizing the influence of preload on coupling disturbance.

[0026] 2. This invention introduces a lever amplification structure into the dual-axis drive path to effectively amplify and stably output the minute axial displacement of the piezoelectric stack to the tool holder, thereby significantly improving the effective stroke of the tool while maintaining the advantages of high frequency response and high resolution of piezoelectric drive.

[0027] 3. This invention combines the four-node finite element method and compliant mechanism design theory, fully utilizing the advantages of topology optimization in structural optimization, and proposes a flexible guiding mechanism based on a four-node model. It uses the SIMP interpolation model from the variable density method to correlate the relationship between material physical parameters and density. Simultaneously, this invention comprehensively considers constraints such as volume fraction, motion decoupling, displacement amplification ratio, and input compliance, achieving a significant improvement in the structure's natural frequency and output displacement performance while effectively reducing structural mass, thus solving the problem of balancing dynamic performance and lightweight design.

[0028] 4. This invention optimizes the shape of both sides of the connecting fulcrum structure of the lever amplification structure and rationally arranges the position of the driving force, so as to reduce the bending moment and stress concentration in the fulcrum area during the force amplification process of the lever, reduce the output displacement error caused by the flexible deformation of the fulcrum, and improve the structural reliability and long-term operating accuracy of the dual-axis amplification drive module. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention.

[0030] Figure 2 This is a front structural diagram of Embodiment 1 of the present invention.

[0031] Figure 3 This is a schematic diagram showing the connection of the substrate, the dual-axis amplification drive module, the dual-axis decoupling module, and the tool holder in Embodiment 1 of the present invention.

[0032] Figure 4 This is a schematic diagram showing the connection between the mounting base and the displacement detection module in Embodiment 1 of the present invention.

[0033] Figure 5 This is a simulation diagram of the maximum displacement deformation of the tool servo device along the x-axis direction provided in Embodiment 1 of the present invention.

[0034] Figure 6 This is a simulation diagram of the maximum displacement deformation of the tool servo device along the y-axis direction provided in Embodiment 1 of the present invention.

[0035] Figure 7 This is an equivalent stress simulation diagram of the tool servo device along the x-axis direction provided in Embodiment 1 of the present invention.

[0036] Figure 8 This is an equivalent stress simulation diagram of the tool servo device along the y-axis provided in Embodiment 1 of the present invention.

[0037] Figure 9 This is a schematic diagram of the analysis domain of the topology optimization method provided in Embodiment 2 of the present invention.

[0038] Figure 10This is a schematic diagram of the iterative process of the topology optimization method provided in Embodiment 2 of the present invention.

[0039] Reference numerals: 1. Base; 2. Mounting base; 2-1. Positioning slot; 2-2. Displacement sensor; 2-3. Support pad; 2-4. Sensor pre-tightening threaded hole; 3. Dual-axis amplification drive module; 3-1. Lever amplification structure; 3-2. Slender decoupling hinge; 3-3. Piezoelectric stack; 4. Dual-axis decoupling module; 4-1. Sine decoupling hinge; 5. Tool holder; 5-1. Positioning solid block; 6. Tool; 7. Straight hinge pre-tightening mechanism; 7-1. Pre-tightening threaded hole. Detailed Implementation

[0040] The present invention will be further described below.

[0041] To more clearly present the objectives, technical solutions, and advantages of this invention, a more detailed explanation will follow with reference to the accompanying drawings and specific embodiments. It should be noted that the specific embodiments described herein are for illustrative purposes only and do not constitute a limitation on the scope of protection of this invention.

[0042] Example 1

[0043] The slender decoupling hinge described in this embodiment refers to a flexible hinge that allows rotation in two or more directions, such as a bidirectional semi-circular notch flexible hinge, an omnidirectional notch flexible hinge, or other flexible hinge structures that meet motion requirements, preferably a flexible hinge with a double straight circle structure.

[0044] like Figure 1 and Figure 2 As shown, a lever displacement amplification dual-axis fully decoupled high-speed tool servo device includes a base 1, a mounting base 2, a dual-axis amplification drive module 3, a dual-axis decoupling module 4, a tool holder 5, a tool 6, and a displacement detection module. The base 1 is fixed to the mounting base 2 through six threaded holes.

[0045] The base 1 has a central receiving groove for accommodating the tool holder 5, two driving receiving grooves for accommodating the dual-axis amplification drive module 3, and two decoupling receiving grooves for accommodating the dual-axis decoupling module 4. The two driving receiving grooves and the two decoupling receiving grooves are sequentially connected around the central receiving groove.

[0046] The dual-axis amplification drive module 3 includes two single-axis drive modules located in two drive receiving slots. Each single-axis drive module includes a lever-guided topology, a piezoelectric stack 3-3, and a straight-plate hinge pre-tensioning mechanism 7. The lever-guided topology includes a lever amplification structure 3-1 and a slender decoupling hinge 3-2. The lever amplification structure 3-1 includes a lever body and a connecting fulcrum structure. The lever body and the connecting fulcrum structure are connected in an L-shape. The end of the connecting fulcrum structure facing away from the lever body is integrated with the base 1, and the lever body and the base 1 form a flexible hinge connection.

[0047] The slender decoupling hinge 3-2 includes two parallel elastic connecting plates. The end of the lever body away from the connecting fulcrum structure is connected to the knife holder 5 via the two parallel elastic connecting plates. The shape of the elastic connecting plates is obtained through topology optimization, with both sides being concave, presenting a near-straight circular structure that gradually narrows from both ends to the middle.

[0048] The piezoelectric stack 3-3 is installed in a corresponding groove structure on the base 1. Both ends of the piezoelectric stack 3-3 abut against the lever body side of the lever amplification structure 3-1 and the straight-plate hinge pre-tightening mechanism 7, respectively. In this embodiment, the piezoelectric stack 3-3 is located between the connecting fulcrum structure and the slender decoupling hinge 3-2, and is close to the connecting fulcrum structure. The piezoelectric stack 3-3 is pre-tightened by the straight-plate hinge pre-tightening mechanism 7.

[0049] The straight-plate hinge pre-tightening mechanism 7 includes a straight-plate flexible hinge, a support block, a pre-tightening threaded hole 7-1, and a pre-tightening screw. Two straight-plate flexible hinges are parallel to each other, and both ends are fixed to the sidewalls of the receiving groove of the base 1. The support block is disposed between the two straight-plate flexible hinges and is integrally formed with them. The pre-tightening threaded hole 7-1 is formed on the base 1. The piezoelectric stack 3-3, the support block, and the pre-tightening threaded hole 7-1 are arranged and aligned sequentially. The pre-tightening screw is threaded into the pre-tightening threaded hole 7-1 and abuts against the side of the straight-plate flexible hinge away from the piezoelectric stack. Through the support and flexible deformation of the straight-plate hinge pre-tightening mechanism 7, the piezoelectric stack 3-3 moves smoothly during the feeding process, ensuring that the piezoelectric stack 3-3 does not deflect, thus guaranteeing the accuracy of the tool displacement.

[0050] In this embodiment, the end of the lever amplification structure 3-1 connected to the slender decoupling hinge 3-2 is taken as the head end, and the end connected to the base 1 is taken as the tail end. Therefore, the connecting fulcrum structure is located at the tail end of the lever amplification structure 3-1. When the lever amplification structure 3-1 is subjected to the thrust of the piezoelectric stack 3-3 and rotates around the tail fulcrum, the tail fulcrum will be subjected to a bending moment; at this time, the tail fulcrum of the lever amplification structure 3-1 will undergo a certain degree of bending deformation, thereby affecting the output displacement accuracy of the dual-axis amplification drive module 3; in this embodiment, the shape of the connecting fulcrum structure at the tail end of the lever amplification structure 3-1 is optimized:

[0051] The connecting fulcrum structure has a straight edge near the piezoelectric stack 3-3 and an arc-shaped edge away from the piezoelectric stack 3-3, comprising a concave arc segment and a convex arc segment. The concave arc segment is connected to the base 1; the convex arc segment smoothly transitions to the side edge of the lever body. Furthermore, placing the driving force direction at a point where the lever body thickness is uniform and close to the fulcrum of the lever amplification structure 3-1 can minimize structural strain caused by fulcrum deformation during operation.

[0052] The first end of the lever amplification structure 3-1, facing away from the side of the tool holder 5, is a convex arc shape. This reduces the weight of the lever amplification structure 3-1 while ensuring smooth force transmission and avoiding stress concentration. The lever amplification structure 3-1 has six hollow structures formed through topology optimization iterations. The shape of the hollow structures is an optimal solution for saving materials while ensuring lightweight movement. Furthermore, since the range of motion is relatively small macroscopically, the substrate is designed to closely fit the shape of the dual-axis amplification drive module 3, without affecting the output range and performance of the device.

[0053] In this embodiment, the shape profile of the lever amplification structure 3-1 is obtained by using a four-node finite element in Matlab software with the help of a classic 99-line topology optimization program, and an optimal profile is obtained when the objective function and constraints have converged.

[0054] The two single-axis drive modules in the dual-axis amplification drive module 3 are perpendicularly distributed to each other and connected in an L-shape to two adjacent sides of the tool holder 5. Through the telescopic movement of the piezoelectric stack 3-3 in the two single-axis drive modules, the tool holder 5 can be driven to move in two degrees of freedom, and the lever amplification structure 3-1 can play a motion amplification role.

[0055] In the dual-axis amplification drive module 3, when a voltage is applied to the piezoelectric stack, due to the inverse piezoelectric effect, an axial force is generated at the output ends before and after the piezoelectric stack, which in turn drives the lever amplification structure 3-1 to amplify the displacement, and the displacement is transmitted through the slender decoupling hinge 3-2.

[0056] like Figure 1 and Figure 2 As shown, the dual-axis decoupling module 4 includes two decoupling units located in two decoupling receiving slots. Each decoupling unit includes two sinusoidal decoupling hinges 4-1 spaced apart and axially symmetrical. The sinusoidal decoupling hinges 4-1 adopt an integrated sinusoidal corrugated elastic sheet structure design. The decoupling unit with the symmetrical double sinusoidal hinge structure not only has bending characteristics, but also has natural stretchability due to the corrugated structure design. Through multiple cycles, the flexibility can be further enhanced, thereby achieving precise adjustment of tensile stiffness.

[0057] Two decoupling units are arranged orthogonally, with one end of each of the two sinusoidal decoupling hinges 4-1 in the same decoupling unit connected to the inner wall of the receiving groove of the base 1. The other end of each of the two sinusoidal decoupling hinges 4-1 in the same decoupling unit is connected to the tool holder 5. The dual-axis decoupling module 4 is used for motion decoupling between the two axes. The principle of the dual-axis motion decoupling mechanism is based on the precise control and isolation of motion in two mutually perpendicular directions (usually the X and Y axes); when the tool holder 5 moves along one of the axes, the dual-axis decoupling module 4 can effectively avoid interfering with or affecting the motion state of the other axis. This structure can greatly improve the motion accuracy and stability of the system.

[0058] The cutting tool 4 is fixed to the front of the tool holder 5; in some embodiments, the cutting tool 4 is a diamond cutting tool. A positioning block 5-1 is fixed to the back of the tool holder 5, and the block works in conjunction with the displacement sensor 2-2 in the displacement detection module to perform necessary positioning and correction of the cutting tool 6.

[0059] The displacement detection module is mainly mounted on the mounting base 2, including a positioning slot 2-1, two displacement sensors 2-2, a support pad 2-3, and two sets of sensor pre-tightening threaded holes 2-4. The positioning slot 2-1 is located at the center of the mounting base 2 and aligned with the center receiving groove of the base 1. The positioning block 5-1 is located inside the positioning slot 2-1. The mounting base 2 has two orthogonally arranged detection holes. Both detection holes communicate with the positioning slot 2-1. The two displacement sensors 2-2 are respectively mounted on the detection holes and fixed by set screws in the sensor pre-tightening threaded holes 2-4. The detection parts of the two displacement sensors 2-2 face the X and Y orthogonal sides of the positioning block 5-1 through the two detection holes. The two displacement sensors 2-2 can detect the dual-axis displacement of the positioning block 5-1, thereby realizing the dual-axis displacement negative feedback control of the tool 6.

[0060] The mounting base 2 has a clearance groove on its side facing the base 1 to prevent the mounting base 2 from interfering with the movement of the dual-axis amplification drive module 3, the dual-axis decoupling module 4, and the tool holder 5. A support pad 2-3 is fixed to the bottom surface of the clearance groove. The support pad 2-3 is in direct contact with the base 1 and is fixed by bolts and threaded holes to reduce vibration of the base 1 caused by the tool during rapid movement. The position of the support pad 2-3 is offset from the dual-axis amplification drive module 3 and the dual-axis decoupling module 4, which helps to minimize the impact of friction on the decoupling movement of the tool, while ensuring a tight connection between the mounting base 2 and the base 1.

[0061] In this embodiment, the dual-axis displacement detection module can detect the displacement direction of the tool holder 5 to realize the servo process of the entire system motion.

[0062] The tool servo device provided in this embodiment has the advantages of large stroke, compact structure, high driving force, high resolution, high frequency response and high motion bandwidth in two-dimensional space.

[0063] In some preferred embodiments, the cutting tool is fixed to the tool holder by a set screw.

[0064] In some preferred embodiments, the tool holder 5 is fixed to the positioning block 5-1 by both set screws and fixing screws.

[0065] The working principle of this invention is as follows:

[0066] The two single-axis drive modules serve as the X-axis drive module and the Y-axis drive module, respectively.

[0067] When it is necessary to control the movement of the tool along the x-axis, the X-axis drive module is activated. By changing the voltage, the piezoelectric stack in the X-axis drive module generates an axial thrust, which in turn drives the corresponding lever amplification structure 3-1 to move. The amplified displacement is transmitted through the corresponding hinge structure, thereby realizing the movement of the tool 6 in the X-axis direction.

[0068] Similarly, when it is necessary to control the tool to move along the y-axis, the y-axis drive module is activated. By changing the voltage, the corresponding piezoelectric stack generates a propulsive force on the axial direction, thereby driving the corresponding lever amplification structure to move, thus realizing the movement of tool 6 in the y-axis direction.

[0069] The tool servo device provided in this embodiment amplifies displacement through levers, enabling complete decoupling of the two axes. It has advantages such as high frequency response, sub-nanometer motion resolution, high driving force, and high motion bandwidth of piezoelectric stack drive, thereby achieving high-efficiency cutting capability in single-point diamond turning.

[0070] To verify the dual-axis decoupled drive performance of the lever displacement amplification dual-axis fully decoupled rapid tool servo device in this embodiment, the tool servo device provided in this embodiment was simulated along the x-axis and y-axis directions using the Static Structural module in ANSYS software, including Total Deformation and Directional Deformation. The results are as follows: Figure 5 and 6 As shown. From Figure 5 and 6 As can be seen, when a force is applied to the input end of a single piezoelectric stack on the x-axis, the tool servo device provided in this embodiment can achieve a maximum total deformation of 3.3964 μm in the x-axis direction; when a force is applied to the input end of the piezoelectric stack on the y-axis, the maximum displacement on the y-axis can reach 3.0895 μm, which has a large stroke displacement and can meet the needs of large stroke processing of complex optical microstructure surfaces.

[0071] In the Static Structural module of ANSYS software, an Equivalent Stress simulation was performed on the tool servo device provided in this embodiment. The strength and safety results under the loads on the x and y axes under Equivalent Stress are shown below. Figure 7 , 8 As shown. From Figure 7 , 8 As can be seen, the equivalent stress on the x-axis of the tool servo device provided in this embodiment is 3.0335 MPa, indicating that the stress level of the component is low and the structural strength is sufficient under the current working conditions. The equivalent stress on the y-axis is 0.031109 MPa, which is far lower than the allowable stress of conventional structural materials, indicating that the component has a high strength redundancy under this working condition and good structural safety.

[0072] Based on the above data, it can be seen that the lever displacement amplification dual-axis fully decoupled rapid tool servo device provided in this embodiment...

[0073] Breaking through the limitations of traditional FTS systems, this invention combines piezoelectric drive with an amplification mechanism to achieve superior performance, meeting the high-precision and long-stroke machining requirements of practical applications. This embodiment uses piezoelectric drive to realize the two-dimensional spatial movement of the tool and can decouple the two axes, offering advantages such as large stroke, compact structure, high driving force, and suppression of motion coupling effects. Four sinusoidal decoupling hinges in two directions around the tool holder minimize the impact of preload on coupling disturbances. The overall architecture of this invention is optimized, compact, easy to install and integrate, structurally sound, stable, and reliable. It features a large planar motion stroke, wide bandwidth, and high motion accuracy, providing an innovative and practical solution for related fields.

[0074] Example 2

[0075] A topology optimization method is provided to optimize the shape (i.e., the distribution of solid and empty parts) of the lever guide topology in the lever displacement amplification dual-axis fully decoupled rapid tool servo device provided in Embodiment 1. It automatically generates a platform structure that meets the requirements of "motion decoupling, displacement amplification, and lightweighting" through a multi-constraint objective topology optimization algorithm. The specific process is as follows:

[0076] Step 1: Establish the objective function of the basic topology optimization model for the lever-guided topology structure as follows:

[0077]

[0078] in, To optimize the set of design variables, For lever-guided topology The relative density of each unit, ranging from [0,1]. n is the number of topological partitioning units in the lever-guided topology.

[0079] Regarding the objective function expression, It is about optimizing the objective function (maximizing the objective), and the core is to balance the dynamic performance of the structure with the output displacement; It is the structure number The eigenvalues ​​corresponding to the first natural frequencies ( The value is the first The square of the first natural angular frequency reflects the dynamic stiffness of the structure; For output port exist The actual output displacement in the direction. For output port exist The target output displacement in the direction, where The direction is the same as the X direction in the design drawing; This is the weighting factor.

[0080] Regarding constraints, , These are the output coupling coefficient and the input coupling coefficient, respectively. , These are the maximum allowable values ​​for the output coupling coefficient and the input coupling coefficient, respectively. , These are displacement amplification ratio and input compliance, respectively. , These are the constraint thresholds corresponding to the displacement amplification ratio and the input compliance, respectively. Represents actual volume, Maximum permissible volume; For the first The maximum volume of the nth unit (i.e., the largest volume of the nth unit) (volume of the space containing each unit). , , , , These are the global stiffness matrix, global mass matrix, nodal displacement vector, external force vector, and mode shape vector, respectively. This represents the minimum relative density of all units. , m and k are the output direction index, cross direction index, modal order, and output direction index, respectively. This represents the total degrees of freedom of the structure.

[0081] Under constraints such as element density range, motion decoupling, displacement amplification ratio, input compliance, and volume, the element density is optimized. This achieves the dual goals of "increasing the natural frequency of the structure and meeting the output displacement target", ultimately resulting in a dual-axis micro-nano positioning platform topology that combines high dynamic performance, long stroke, and low coupling.

[0082] Step 2: Analytical domain partitioning.

[0083] 2-1. Establish and distribute the analysis domain.

[0084] In this embodiment, the size of the analysis domain is Discretize it into Each finite element mesh element has a size of 1mm × 1mm × 1mm.

[0085] 2-2. Divide the analysis domain.

[0086] The basic structural layout for topology optimization of the positioning platform is constructed, and the analysis domain is divided into three core regions:

[0087] (1) Design Domain Present The shape is the core region of topology optimization, and the cell density will decrease from its minimum value during the iteration process. It is gradually updated to version 1, eventually forming the optimized main structure.

[0088] (2) Entity non-design domain Area is A rectangular area is used to set the output port. The unit density within the region is fixed at 1 to ensure the structural stiffness of the output end.

[0089] (3) Empty non-design domain : Blank areas reserved for the structure, which do not participate in material distribution optimization and are used to avoid structural interference.

[0090] In the design domain input port and Apply vertically upward forces respectively. and a force to the right horizontally Each is equipped with a virtual spring as a guiding mechanism; at the output port and A virtual spring is connected to ensure output stiffness. When subjected to force, it will generate output displacement and output force in the corresponding direction.

[0091] Step 3: Topology Optimization Iteration

[0092] Based on preset design domain parameters, material properties, and constraints, structural optimization is achieved by progressively updating the element density. The core iterative process revolves around the iterative evolution diagram, as detailed below:

[0093] 3-1. In the iterative initialization phase, initialize the relative density of all elements within the design domain, and set the design domain... The density of each unit within the cell is initially set to a uniform distribution; for example... Figure 10 As shown, when the number of iterations reaches 5, there is no obvious differentiation between the solid region (black part), the transition region (gray part) and the empty region (white part) in the iteration diagram. Only the basic initial layout is presented, which lays the initial structural foundation for subsequent iteration optimization.

[0094] 3-2. In the early iterative evolution stage, based on the core formula of the SIMP interpolation method The element density is updated by combining the preset objective function (increasing natural frequency and output displacement) and constraints (motion decoupling, volume fraction, etc.). Figure 10 As shown, when the number of iterations reaches 10 to 20, it can be seen in the iteration diagram that the solid regions (black parts) gradually gather and initially form a general distribution trend, the empty regions (white parts) begin to appear, the transition regions (gray parts) still occupy a certain proportion, the structure initially evolves in the direction of meeting the constraint requirements, and the invalid material regions are gradually eliminated.

[0095] 3-3. In the mid-term iterative optimization stage, as the number of iterations increases, the accuracy of the unit density update improves, and the structural morphology is further optimized. For example... Figure 10 As shown in the figure, when the number of iterations reaches 50, the iteration diagram shows that the solid region (black part) gradually forms a more regular and continuous main structure, the area of ​​the transition region (gray part) continues to shrink, the distribution of the empty region (white part) becomes more reasonable, the material distribution of the region corresponding to the input / output port of the structure gradually becomes clear, the structural separation characteristics required for motion decoupling are initially revealed, and the core performance indicators such as natural frequency and output displacement gradually approach the target value.

[0096] 3-4. In the later iterative convergence phase, the iteration process terminates when the number of iterations reaches the preset maximum number of iterations (99 times). For example... Figure 10 As shown, when the number of iterations reaches 80-99, the solid region (black part) in the iteration diagram forms a stable and continuous optimal topology, the transition region (gray part) basically disappears, and the distribution of the empty region (white part) and the boundary of the solid region are clear. The structure fully meets the preset volume fraction constraint (0.2). When the optimized structure is subjected to force through the input port, it can achieve stable deformation and motion output in the dual-axis direction. The constraint indicators such as motion coupling ratio and displacement amplification ratio all meet the standards, and finally a dual-axis micro-nano positioning platform topology configuration that meets the design requirements is formed.

[0097] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A lever displacement amplification dual-axis fully decoupled rapid tool servo device, comprising a base (1), a dual-axis amplification drive module (3), and a tool holder (5), characterized in that: It also includes a dual-axis decoupling module (4); The dual-axis amplification drive module (3) includes two orthogonally arranged single-axis drive modules; the single-axis drive module includes a lever amplification structure (3-1) and a piezoelectric stack (3-3); the lever amplification structure (3-1) is configured to amplify the displacement output by the piezoelectric stack (3-3) and transmit it to the tool holder (5). The dual-axis decoupling module (4) includes two decoupling units; each decoupling unit includes two sinusoidal decoupling hinges (4-1) that are spaced apart and axially symmetrical; the two decoupling units correspond to two single-axis drive modules respectively; the corresponding decoupling units and single-axis drive modules are respectively connected to a set of opposite sides of the tool holder (5).

2. The lever displacement amplification dual-axis fully decoupled rapid tool servo device according to claim 1, characterized in that: The single-axis drive module also includes a slender decoupling hinge (3-2); one end of the lever amplification structure (3-1) is connected to the base (1) by a flexible hinge; the slender decoupling hinge (3-2) is connected to the other end of the lever amplification structure (3-1) and to the tool holder (5); the slender decoupling hinge (3-2) includes two elastic connecting pieces that are parallel to each other.

3. The lever displacement amplification dual-axis fully decoupled rapid tool servo device according to claim 2, characterized in that: The lever amplification structure (3-1) includes a lever body and a connecting fulcrum structure; the lever body and the connecting fulcrum structure are connected in an L-shape; the end of the connecting fulcrum structure away from the lever body is integrated with the base (1).

4. The lever displacement amplification dual-axis fully decoupled rapid tool servo device according to claim 3, characterized in that: The edge of the connecting fulcrum structure near the piezoelectric stack (3-3) is straight; the edge of the connecting fulcrum structure away from the piezoelectric stack (3-3) is arc-shaped, including a concave arc segment and a convex arc segment; the concave arc segment is connected to the substrate (1); the convex arc segment is smoothly connected to the side edge of the lever body.

5. The lever displacement amplification dual-axis fully decoupled rapid tool servo device according to claim 3, characterized in that: The head end of the lever body is convex arc-shaped away from the side of the knife holder (5); the lever amplification structure (3-1) is provided with multiple hollow structures formed by topology optimization iteration; the position of the hollow structure is offset from the support point position of the piezoelectric stack (3-3).

6. The lever displacement amplification dual-axis fully decoupled rapid tool servo device according to claim 1, characterized in that: The piezoelectric stack (3-3) abuts against the side of the lever amplification structure (3-1); the piezoelectric stack (3-3) is provided with preload through the straight plate hinge preload mechanism (7).

7. The lever displacement amplification dual-axis fully decoupled rapid tool servo device according to claim 1, characterized in that: The substrate (1) has a central receiving groove for accommodating the tool holder (5), the dual-axis amplification drive module (3) and the dual-axis decoupling module (4).

8. The lever displacement amplification dual-axis fully decoupled rapid tool servo device according to claim 1, characterized in that: It also includes a mounting base (2) and a displacement detection module; the mounting base (2) is fixed to the base (1); the displacement detection module includes a positioning slot (2-1) opened in the mounting base (2), two detection holes orthogonally arranged and connected to the positioning slot (2-1), and a displacement sensor (2-2); the positioning slot (2-1) is aligned with the tool holder (5); the back of the tool holder (5) is fixed with a positioning block (5-1) located in the positioning slot (2-1); the two displacement sensors (2-2) are respectively installed on the detection holes; the detection parts of the two displacement sensors (2-2) are respectively directed to the two orthogonal sides of the positioning block (5-1) through the two detection holes.

9. A lever displacement amplification dual-axis fully decoupled rapid tool servo device according to claim 8, characterized in that: The mounting base (2) has a clearance groove on the side facing the base (1); a support pad (2-3) is provided on the bottom surface of the clearance groove; the support pad (2-3) contacts the base (1) and is fixed by bolts; the position of the support pad (2-3) is offset from the dual-axis amplification drive module (3) and the dual-axis decoupling module (4).

10. A topology optimization method, characterized in that: Used to optimize a lever displacement amplification dual-axis fully decoupled rapid tool servo device as described in claim 1; The topology optimization method includes: Construct the objective function The constraints are set, including constraints on output coupling coefficient, input coupling coefficient, displacement amplification ratio, input flexibility, and element relative density. in, To optimize the set of design variables, Let be the relative density of the unit cells in the lever-guided topology, i = 1, 2, ..., n; and n be the number of topological partitioning units in the lever-guided topology. For the first The eigenvalues ​​corresponding to the first natural frequencies; As a weighting factor; , These are the actual output displacement and the target output displacement of the output port, respectively. An analysis domain is established that includes the area where the dual-axis amplification drive module (3) and the tool holder (5) are located. The analysis domain is divided into a design domain corresponding to the lever-guided topology, a solid non-design domain corresponding to the tool holder (5), and an empty non-design domain. Two input ports are set at the position where the two piezoelectric stacks (3-3) apply thrust on the design domain. Two output ports are set in the solid non-design domain. The two input ports and the two output ports are equipped with virtual springs respectively. The design domain is iteratively optimized based on the objective function and constraints to obtain the optimized lever-guided topology.

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