Novel decoupling double-shaft elliptical vibration auxiliary cutting platform and control method thereof

Abstract

The invention discloses a novel decoupling double-shaft elliptical vibration auxiliary cutting platform and a control method thereof. The novel decoupling double-shaft elliptical vibration auxiliary cutting platform comprises a base, a corner mounting seat, a middle mounting seat, two driving units and a cutter mounting block, wherein the two driving units are vertically arranged at an angle of 90 degrees. The driving unit comprises a piezoelectric actuator, a swing block, a movement restraining block, an amplification output block and a fixing block. The two opposite side faces of the swing block are connected with the corner installation base and the middle installation base through flexible hinges respectively. And the two groups of moving constraint blocks and amplification output blocks are respectively connected with the two sides of the opposite surfaces of the swing block and the fixed block through flexible hinges. And the amplification output block is in flexible transmission connection with the cutter mounting block. Double parallel straight plate hinges are used as an input guide mechanism, and double parallelogram mechanisms are used as an output guide mechanism. By the adoption of the guide mechanism, the device has the advantages of being good in flexibility, high in precision, controllable in motion trail and the like.

Description

Technical Field

[0001] The present invention relates to the field of elliptical vibration assisted cutting (EVC) technology and mechanism motion modeling and design, and more specifically, to the application of flexible mechanism design theory and method and piezoelectrically actuated high-precision micro-nano positioning platform and other related fields. Background Art

[0002] Elliptical vibration assisted cutting (EVC) is an advanced manufacturing technology. Due to its superior precision machining performance when machining difficult-to-machine materials, it has been widely used in many fields, including micro-nano structure manufacturing, optical mold manufacturing, and composite material processing. However, with the growing demand for high-precision and complex structures in the manufacturing industry, the design of high-performance elliptical vibration assisted cutting (EVC) devices faces several new challenges.

[0003] First, the spatial complexity of the micro-nanostructure surface inevitably requires the tool to have multiple degrees of freedom to match the required geometry. Second, the extreme miniaturization of the device size requires the tool to have a higher working bandwidth and relative stability. Finally, in addition to ensuring high precision and high performance, the design must also consider cost-effectiveness and find a balance between precision requirements and manufacturing costs.

[0004] The driving force in EVC is mainly achieved by piezoelectric actuators, which have the advantages of high rigidity, fast frequency response and precise positioning accuracy. Motion guidance mechanisms are generally divided into four categories: flexible hinge mechanisms, high-precision gas bearings, ultrasonic suspension and magnetic suspension. Considering factors such as structural size and cost, flexible hinge mechanisms are mainly used to achieve force transmission and motion guidance at submillimeter and millimeter scales. At present, the main theoretical frameworks and methods for motion modeling and design of EVC mechanisms include pseudo-rigid body theory, integral card second theorem (ICST), finite element analysis (FEA), inverse kinematics modeling (IKM) based on Lagrange equations, screw theory (ST) and matrix-based flexibility modeling (MCM). However, due to the coupling characteristics between motions, the design method of EVC mechanisms faces challenges, which limits the improvement of the performance of dual-axis EVC worktables.

[0005] In summary, given that the screw theory (ST) is geometrically intuitive and efficient in kinematic analysis, and matrix-based flexibility modeling provides higher accuracy and simplicity in static analysis and small deformation behavior description, the present invention proposes a method that combines the stiffness matrix method with the screw theory. This comprehensive method is used to reconstruct the mathematical model of the EVC workbench flexible mechanism to analyze its kinematic, static and dynamic characteristics. In order to further improve the accuracy and efficiency of ultra-precision auxiliary equipment, the development of the cutting platform requires not only the design of the mechanical structure but also the control of the motion. Considering the simplicity of the PID controller, the convenience of parameter adjustment and the effective control ability, and its strong compatibility with other control algorithms, the problem of achieving high-performance motion control in the EVC system is solved by combining the coupled PID control strategy with dynamic feedforward control. Therefore, this invention not only provides important reference and guidance for multiple fields such as precision engineering, elliptical vibration-assisted cutting, and topological optimization design of flexible mechanisms, but also has certain academic and practical value. Summary of the invention

[0006] The purpose of the present invention is to provide a novel decoupled dual-axis elliptical vibration assisted cutting platform and a structural design method thereof.

[0007] In the first aspect, the present invention provides a novel decoupled dual-axis elliptical vibration assisted cutting platform, which includes a base, a corner mounting seat, a middle mounting seat, two drive units arranged vertically at a 90° angle, and a tool mounting block. The corner mounting seat and the middle mounting seat are both fixed at the corners of the base. The two drive units are both connected between the corner mounting seat and the middle mounting seat. The drive unit includes a piezoelectric actuator, a pendulum block, a mobile constraint block, an amplifying output block and a fixed block. The two opposite sides of the pendulum block are respectively connected to the corner mounting seat and the middle mounting seat by flexible hinges. The fixed block is fixed on the base. Two groups of mobile constraint blocks and the amplifying output block are respectively connected to the two sides of the opposite surfaces of the pendulum block and the fixed block by flexible hinges. The piezoelectric actuator is connected between the fixed block and the pendulum block. The amplifying output block is flexibly connected to the tool mounting block.

[0008] During operation, the telescopic movement of the piezoelectric actuator is amplified and rotated 90° through the swing block, the mobile constraint block, and the amplified output block. The two drive units jointly drive the tool mounting block to move in two degrees of freedom.

[0009] Preferably, the driving unit further comprises two directional constraint beams arranged between the amplifying output block and the tool mounting block. One end of the two directional constraint beams parallel to each other is connected to two positions on the same side of the corresponding amplifying output block through a flexible hinge. The other end of the two directional constraint beams parallel to each other is connected to two positions on the same side of the corresponding tool mounting block through a flexible hinge.

[0010] Preferably, the tool further comprises a displacement detection component, wherein the displacement detection component comprises two displacement sensors. Both displacement sensors are fixed to the base and face the tool mounting block or the displacement detection identification block fixed on the tool mounting block. The detection directions of the two displacement sensors are perpendicular to each other.

[0011] Preferably, the flexible hinges between the pendulum block and the movable constraint block, between the movable constraint block and the amplifying output block, between the amplifying output block and the direction constraint beam, and between the direction constraint beam and the tool mounting block are semicircular flexible hinges; the hinge thickness of the semicircular flexible hinge is 0.4mm to 0.8mm, and more preferably 0.5mm.

[0012] Preferably, the radius of the semicircular flexible hinge is 1 mm to 2 mm, more preferably 1.5 mm.

[0013] Preferably, the flexible hinges between the pendulum block and the corner mounting seat and the middle mounting seat are connected by double parallel straight plate hinges.

[0014] Preferably, the flexible hinge between the amplifying output block and the fixed block is connected by a double parallel straight plate hinge.

[0015] Preferably, two ends of the piezoelectric actuator respectively abut against opposite ends of the pendulum block and the fixed block and are pre-tightened by bolts.

[0016] In a second aspect, the present invention provides a cutting platform structure optimization method, characterized in that it is used to optimize a novel decoupled dual-axis elliptical vibration assisted cutting platform as described in claim 1. The cutting platform structure optimization method is as follows:

[0017] Construct the stiffness matrix for the first drive unit; According to the 90° rotationally symmetrical relative position between the two drive units, the stiffness matrix of the second drive unit is obtained by rotating the stiffness matrix of the first drive unit; The stiffness matrix corresponding to the two drive units is used to form the stiffness model of the entire cutting platform; According to the stiffness model, the objective function of structural optimization is established, the structural parameters of the drive unit are adjusted, the overall stiffness of the cutting platform is optimized, the ability of the cutting platform to withstand cutting forces is enhanced, and while ensuring stiffness control, the frequency is optimized to facilitate error compensation in subsequent cutting processing.

[0018] Preferably, the optimized structural parameters include the sizes of the pendulum block, the movement constraint block, the amplified output block, the fixed block and the direction constraint beam, as well as the sizes of each flexible hinge.

[0019] In a third aspect, the present invention provides a cutting control method, which uses the aforementioned novel decoupled dual-axis elliptical vibration assisted cutting platform. The cutting control method is as follows: two drive units are used as two controlled systems respectively; the two controlled systems are dynamically controlled according to the displacement error of the tool mounting block (6).

[0020] Preferably, the dynamic control of the two controlled systems is performed by means of PID controllers.

[0021] The present invention has the following beneficial effects.

[0022] 1. In the present invention, two drive units are arranged orthogonally, and a new decoupling bridge-type amplification structure is used in the drive unit, so that the two-axis drive of the tool is realized and the axial coupling existing in the output displacement of the two-axis cutting platform is effectively suppressed.

[0023] 2. The present invention performs stiffness matrix modeling for a single drive unit, and obtains the stiffness matrix of the second drive unit by rotating 90° around the z-axis and flipping 180° around the x-axis, thereby conveniently and accurately obtaining the overall stiffness model of the dual-axis cutting platform, and then using the stiffness model to achieve rapid optimization of the drive unit structural parameters, thereby improving the performance of the hardware, while improving the stiffness to resist cutting force and obtaining the optimal frequency for error compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to better interpret the patent of the present invention, the following will briefly introduce the implementation drawings of the technical solution of the present invention. Obviously, the following drawings are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 It is a schematic diagram of the overall structure of Example 1 of the present invention.

[0026] Figure 2 It is a schematic diagram of the back structure of Example 1 of the present invention.

[0027] Figure 3 It is a schematic diagram of the connection structure between two drive units and a tool mounting block in Example 1 of the present invention.

[0028] Figure 4 It is a schematic diagram of the positions of the coordinate systems corresponding to the rigid bodies when the rigidity model is established in Example 2 of the present invention.

[0029] Figure 5 This is a system block diagram of a PID controller with a feedforward compensator used in Example 2 of the present invention.

[0030] Figure 6 This is a Y-axis driving simulation diagram of Example 2 of the present invention.

[0031] Figure 7 This is an x-axis drive simulation diagram of Example 2 of the present invention.

[0032] Figure 8 It is a sinusoidal trajectory tracking diagram of the driving cutting platform in different directions in Example 2 of the present invention.

[0033] Fig. 9 This is a trajectory tracking diagram of a nano-stepping experiment in which a cutting platform is driven in different directions in Example 2 of the present invention.

[0034] Fig.10 This is a trajectory tracking diagram of the harmonic superposition signal experiment of the driving cutting platform in Example 2 of the present invention.

[0035] Figure markings: 1. base; 2. corner mounting seat; 3. driving unit; 3-1. piezoelectric actuator; 3-2. pendulum block; 3-3. movement constraint block; 3-4. amplification output block; 3-5. fixed block; 3-6. direction constraint beam; 4. middle mounting seat; 5. displacement detection assembly; 5-1. sensor mounting seat; 5-2. displacement sensor; 6. tool mounting block; 7. diamond tool. DETAILED DESCRIPTION

[0036] In order to more clearly illustrate the purpose, technical solutions and advantages of the present invention, the embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0037] Example 1 like Figure 1 , Figure 2 As shown, a novel decoupled dual-axis elliptical vibration assisted cutting platform includes a base 1, a corner mounting seat 2, a middle mounting seat 4, two drive units 3 arranged vertically at a 90° angle, a tool mounting block 6 and a displacement detection component 5. The corner mounting seat 2 is fixed to the corner of the base 1 by bolts. Both drive units 3 are movably connected between the corner mounting seat 2 and the middle mounting seat 4. The two drive units 3 jointly drive the tool mounting block 6 to move freely in the plane in the x-axis and y-axis directions. The displacement detection component 5 is used to detect the displacement of the tool mounting block 6 in the xy plane.

[0038] The driving unit 3 includes a piezoelectric actuator 3-1, and a pendulum block 3-2, two movable constraint blocks 3-3, two amplification output blocks 3-4, a fixed block 3-5 and two directional constraint beams 3-6 that constitute a decoupled bridge amplification structure.

[0039] The specific connection method of the decoupled bridge amplification structure is as follows: the two opposite sides of the pendulum block 3-2 are connected to the corner mounting seat 2 and the middle mounting seat 4 respectively through double parallel straight plate hinges. The fixed block 3-5 is fixed to the base 1 by bolts. The two mobile constraint blocks 3-3 and the two amplification output blocks 3-4 are arranged between the pendulum block 3-2 and the fixed block 3-5. One end of the two mobile constraint blocks 3-3 is connected to the two ends of the same side of the pendulum block 3-2 respectively through flexible hinges. One end of the two mobile constraint blocks 3-3 is connected to one end of the two amplification output blocks 3-4 respectively through flexible hinges.

[0040] The two ends of the piezoelectric actuator 3-1 are respectively against the opposite ends of the pendulum block 3-2 and the fixed block 3-5, and are pre-tightened by bolts. The two ends of the same side of the amplifying output block 3-4 located near the tool mounting block 6 are connected to one end of the two-direction constraint beam 3-6 through a flexible hinge. The two ends of the side of the tool mounting block 6 facing the amplifying output block 3-4 are connected to the other end of the two-direction constraint beam 3-6 through a flexible hinge.

[0041] In the decoupled bridge amplification structure of this embodiment, the swing block 3-2, two moving constraint blocks 3-3, two amplification output blocks 3-4, and one fixed block 3-5 form an input guide mechanism, which is used to ensure that the movement direction of the amplification output block 3-4 of the tool mounting block 6 is perpendicular to the piezoelectric actuator 3-1. Two mutually parallel direction constraint beams 3-6 form a parallelogram mechanism, which helps to keep the movement direction of the tool mounting block 6 consistent with the connected amplification output block 3-4.

[0042] The two drive units 3 are rotationally symmetrical at 90°, and the telescopic directions of the piezoelectric actuators 3-1 in the two drive units 3 are parallel to the x-axis and the y-axis respectively. The presence of the input guide mechanism enables the amplified output block 3-4 close to the tool mounting block 6 to provide a stable and precise amplified movement perpendicular to the telescopic direction of the piezoelectric actuator 3-1; thereby, the drive unit 3 whose telescopic direction of the piezoelectric actuator 3-1 is parallel to the x-axis is used for the translation of the tool mounting block 6 along the y-axis. The drive unit 3 whose telescopic direction of the piezoelectric actuator 3-1 is parallel to the y-axis is used for the translation of the tool mounting block 6 along the x-axis.

[0043] The displacement detection assembly 5 includes a sensor mounting seat 5-1 and two displacement sensors 5-2. The sensor mounting seat 5-1 is fixed on the middle mounting seat 4. The two displacement sensors 5-2 are respectively fixed to the two ends of the sensor mounting seat 5-1 by bolts, and both face the tool mounting block 6. The detection directions of the two displacement sensors 5-2 are perpendicular to each other, and in this embodiment, they are parallel to the x-axis and the y-axis respectively.

[0044] In this embodiment, the displacement sensor 5 - 2 is a capacitive displacement sensor 5 - 2 ; in some other embodiments, the displacement sensor 5 - 2 may also be other existing displacement sensors 5 - 2 such as a laser displacement sensor 5 - 2 .

[0045] In this embodiment, a diamond tool 7 is mounted on the tool mounting block 6. A displacement detection identification block fixed at the front end of the diamond tool 7 cooperates with two displacement sensors 5-2 to measure the displacement of the diamond tool 7 in two axial directions.

[0046] Example 2 A cutting platform control method is a method combining a stiffness matrix method with a screw theory. It is used to reconstruct a mathematical model of an EVC worktable flexible mechanism to analyze its kinematic, static and dynamic characteristics, so as to accurately drive the novel decoupled dual-axis elliptical vibration-assisted cutting platform provided in Example 1.

[0047] The cutting platform control method comprises the following steps: Step 1: Establish the stiffness matrix model of the entire cutting platform as follows: Based on the Lagrange equation, the dynamic differential equation describing the cutting platform can be expressed as: Formula (1) in, and denote the displacement vector and acceleration vector respectively; and denote the mass matrix and stiffness matrix respectively; Represents the external force vector.

[0048] Next, the cutting platform stiffness matrix Using the observation method, the stiffness matrix Mid-diagonal elements represents the total stiffness calculated by all elastic elements connected to the front of the i-th rigid body. Represents the composite stiffness calculated by the elastic element connecting the ith rigid body and the jth rigid body.

[0049] Establish , mass matrix , stiffness matrix , external force vector as follows: Formula (2) in, Extract the diagonal matrix.

[0050] matrix and The i-th element of is represented as: Formula (3) When only free vibration is considered, is set to zero. By Set to zero, the static force-displacement relationship can be derived from equation (1). When the force vector When , the output displacement vector can be expressed as:

[0051] Formula (4) Stiffness Matrix In The diagonal submatrix of is derived as follows: Assume that The flexible element is connected to the ith rigid body. Establishment: The coordinate system is a coordinate system with a point on the i-th rigid body as the origin; for the j-th rigid body In the case of one-way translation on the coordinate axis of the coordinate system Coordinate system, get the origin On the jth rigid body Coordinate system. For the jth rigid body not in In the case of coordinate system coordinate axis; bidirectional translation Coordinate system, get the origin on the jth rigid body Coordinate system.

[0052] The displacement of the i-th rigid body from Coordinate system conversion to The coordinate system is expressed as: Formula (5) in, is the i-th rigid body Displacement spinor in coordinate system; is from Coordinate system to Coordinate transformation matrix of the coordinate system; and Represent the rotation matrix and position matrix respectively.

[0053] Formula (6) When the force vector f i,j =[ f x,i,j , f y,i,j , f z,i,j ] T Act on point When, about The additional torque vector for: Formula (7) in, for point to The direction vector of .

[0054] express The force component acting on The equivalent spinor It can be described as: F i = [ f i , m i ] T = J i,j F i,j = J i,j K j,i ∆ d i,j = J i,j K j,i J i,j T ∆ d i Formula (8) Therefore, the matrix Has the following form: Formula (9) Stiffness Matrix The matrix in Derivation of the non-diagonal matrix: Assume that there is A flexible element connects the i-th rigid body and the j-th rigid body, and the displacement of the j-th rigid body is from Coordinate system conversion to The expression of the coordinate system is: Formula (10) in, is from Coordinate system to The coordinate transformation matrix of the coordinate system. and Represent the rotation matrix and position matrix respectively.

[0055] Act on point The force twist is: Formula (11) Rotate the force from Coordinate system conversion to Coordinate system, we get: Formula (12) Therefore, the matrix It can be expressed as: Formula (13) Step 2: Kinematic modeling description: like Figure 4 As shown, the coordinate origins of the coordinate systems on the pendulum block 3-2, the two moving constraint blocks 3-3, the two amplifying output blocks 3-4, the fixed block 3-5, the two directional constraint beams 3-6 and the tool mounting block 6 are set to be O1~O8 respectively, and the forces are set to be F1~F8 respectively.

[0056] According to the static equilibrium condition, the elastic model of the bridge-type amplification structure can be expressed as: Formula (14) in, Indicates from point To point Stiffness; Indicates force Under the effect, point Horizontal displacement of Indicates force Under the effect, point The vertical displacement of and It can be expressed as:

[0057] Formula (15) in, is from Coordinate system to Coordinate transformation matrix of the coordinate system; is from Coordinate system to Coordinate transformation matrix of the coordinate system; It is from the point To point Stiffness; It is from the point To point Stiffness. Point The center point of the flexible hinge connecting the mobile constraint block 3-3 to the pendulum block 3-2; The center point of the flexible hinge of the mobile constraint block 3-3 is connected to the enlarged output block 3-4.

[0058] Amplification factor of the input guide mechanism in the drive unit , calculated by the following formula: Formula (16) in, , .

[0059] Step 3: Stiffness modeling description: First, perform stiffness modeling on the output end. To coordinate system The stiffness matrix can be expressed as:

[0060] K ̃ 1,1,out = ∑ j=1 4 J 1,j K 1,j (L) J 1,j T + [ T 4,1 K ̃ 4,4 T 4,1 T −1 + T 2,1 K ̃ 2,4 T 2,1 T −1 + K ̃ 1,2 −1 ] −1 Formula (17) in, ,express Hinge stiffness on the right side; ,express and Hinge stiffness between coordinate systems; ,express and The stiffness of the hinge between the coordinate systems.

[0061] From the coordinate system To coordinate system The stiffness matrix can be expressed as: K ̃ 5,5,out = ∑ j=1 2 J 5,j K 5,j (L) J 5,j T + [ T 3,5 K ̃ 3,1 T 3,5 T −1 + T 2,1 K ̃ 5,3 T 2,1 T −1 T 1,5 K ̃ 1,1,out T 1,5 T −1 ] −1 Formula (18) in, express The hinge stiffness below the coordinate system; express and Hinge stiffness between coordinate systems; express and The stiffness of the hinge between the coordinate systems. is from arrive The coordinate transformation matrix.

[0062] Considering that the two drive units of the cutting platform have a symmetrical structure; the stiffness of the first drive unit at the output end calculated above can be converted to the stiffness of the second drive unit at the output end by first rotating 90° counterclockwise around the z-axis and then rotating 180° clockwise around the x-axis to obtain the stiffness matrix of the input guide mechanism in the second drive unit as follows: Formula (20) Therefore, the output stiffness of the input guide mechanism in the drive unit It can be expressed as: (twenty one) Then, the input end stiffness modeling is performed. from The stiffness concentration is converted to The stiffness can be divided into two steps.

[0063] (1) Confirm to The stiffness can be described as: Formula (22) in , , as well as .

[0064] (2) Calculate from arrive The stiffness of and The relationship between is in series. Therefore, the stiffness can be described as:

[0065] K ̃ 1,1,1 = ∑ j=1 4 J 1,j K 1,j (L) J 1,j T + [ T 1,5 K ̃ 5,5,in T 1,5 T −1 + K ̃ 1,3 −1 + T 1,3 K ̃ 3,5 T 1,3 T −1 ] −1 Formula (23) in , .

[0066] Therefore, the input guide mechanism in the drive unit is at point The input stiffness is: Formula (24) in , .

[0067] The present invention selects aluminum alloy as the structural material of the cutting platform, with an elastic modulus of "E=71 GPa" and a density of "ρ=2.7×10⁻³ kg / m³". In order to solve the multi-parameter minimization problem, the differential evolution (DE) algorithm is used to determine the optimal size. The design goal is to achieve high bandwidth and high output stiffness. Therefore, the objective function is defined as:

[0068] (29) in, , , are the first and second order natural frequencies of the cutting platform respectively; , Enter the stiffness matrix of the guide mechanism in the two drive units; , , , are four weight vectors.

[0069] Considering the overall size of the cutting platform, the constraints of the dimensional parameters are listed in Table 1. As shown in the table, according to the dimensional and geometric constraints imposed by SPA, the ranges of the 11 optimization parameters are all set accordingly to ensure the compactness of the overall mechanical structure of the dual-axis EVC platform. The increase of will inevitably improve some characteristics. Therefore, the weight vector : : : The final choice is 2:2:1:2 to effectively balance these weights and obtain the optimal structural parameters. Input stiffness ( , ) is 20.02N / µm, the first-order frequency ( ) is 1641.4Hz, the second-order frequency ( ) is 1641.4Hz.

[0070] Table 1 Structural optimization results, unit: mm. parameter #timg# #timg# #timg# #timg# #timg# #timg# Parameter range [0.4, 0.8] #heart# [10, 15] #heart# [1, 2] #heart# [0.4, 0.8] #heart# [4, 8] #heart# [1, 2] #heart# Best Value 0.5 #timg# #timg# #timg# #timg# #timg# parameter #timg# #timg# #timg# #timg# Parameter range. [5, 10] #heart# [10, 15] #heart# [0.4, 0.8] #heart# [4, 8] #heart# Best Value #timg# #timg# #timg# #timg# Among them (see Fig. 9 ): is the width of the constrained beam; is the length of the constrained beam; is the radius of the semicircular flexible hinge connected to the other end of the beam constrained in two directions; The width of the hinge connecting the two enlarged output blocks and the fixed block; is the length of the hinge connecting the two enlarged output blocks and the fixed block; is the radius of the semicircular flexible hinge between the two enlarged output blocks and the fixed block; To enlarge the width of the output block; To enlarge the length of the output block; The width of the double parallel straight plate hinge connecting the swing block and the middle mounting seat; It is the length of the double parallel straight plate hinge connecting the swing block and the middle mounting seat.

[0071] Step 4: Closed-loop test description: In this embodiment, a classic PID controller combined with a dynamic feedforward compensator based on an inverse hysteresis model is used as the main controller, such as Figure 5 As shown. G(s) represents the unfiltered controlled system and The parameters of the PID controller are obtained by repeated trials, and the transfer functions of the feedforward compensator are expressed as and .

[0072] In order to test the trajectory tracking capability of the cutting platform, a simulation was performed to track a sinusoidal trajectory with an amplitude of 10 μm and a frequency of 100 Hz. The simulation results of driving the tool mounting block along the y direction are shown in Figure 2. Figure 6 The simulation results along the x direction are shown in Figure 7 As shown;

[0073] The trajectory tracking results of the nano-stepping experiment of the cutting platform are as follows: Fig. 9 shown; from Fig. 9 It can be seen that the cutting platform tracks the trajectory along the x-axis and y-axis at the same time, and the corresponding tracking errors are ±0.09μm and ±0.08μm respectively. The tracking accuracy is approximately ±0.9% and ±0.8% respectively. In addition, in order to verify the motion resolution and positioning accuracy of the cutting platform under closed-loop conditions, a nanometer-level step tracking experiment was carried out, with a position change of 5nm per second. The tracking results are shown in Figure 6 As shown in the figure, the designed controller can reliably achieve stable closed-loop positioning with a resolution of 5nm and effectively realize nanometer-level positioning. In order to further reflect the high precision of the designed device, harmonic superposition signals are used to drive the two axes separately.

[0074] Formula (25) The trajectory tracking results of the harmonic superposition signal experiment of the cutting platform are as follows: Fig.10 As shown. The results show that the maximum tracking errors of the x-axis and y-axis are "±0.08µm" and "±0.11µm" respectively. Based on the x-axis motion range of 15μm, the maximum tracking error is about 0.79% of the total motion range. Similarly, the maximum tracking error of the y-axis is about 1.33%. The results show that the learning platform provided in this embodiment can effectively track complex trajectories for layered surface texturing.

Claims

1. A new type of decoupled dual-axis elliptical vibration assisted cutting platform, characterized in that: The invention comprises a base (1), a corner mounting seat (2), a middle mounting seat (4), two drive units (3) arranged vertically at a 90° angle, and a tool mounting block (6); the corner mounting seat (2) and the middle mounting seat (4) are both fixed at the corners of the base (1); the two drive units (3) are both connected between the corner mounting seat (2) and the middle mounting seat (4); the drive unit (3) comprises a piezoelectric actuator (3-1), a pendulum block (3-2), a movement constraint block (3-3), an amplifying output block and a fixing block (3-4); -5); two opposite side surfaces of the pendulum block (3-2) are respectively connected to the corner mounting seat (2) and the middle mounting seat (4) via flexible hinges; the fixed block (3-5) is fixed on the base (1); two groups of movable constraint blocks (3-3) and the amplifying output block are respectively connected to the two sides of the opposite surfaces of the pendulum block (3-2) and the fixed block (3-5) via flexible hinges; the piezoelectric actuator (3-1) is connected between the fixed block (3-5) and the pendulum block (3-2); and the amplifying output block is flexibly connected to the tool mounting block (6).

2. According to claim 1, the novel decoupled dual-axis elliptical vibration assisted cutting platform is characterized by: It also includes a displacement detection component (5); the displacement detection component (5) includes two displacement sensors (5-2); the two displacement sensors (5-2) are both fixed to the base (1) and both face the tool mounting block (6) or the displacement detection identification block fixed on the tool mounting block (6); the detection directions of the two displacement sensors (5-2) are perpendicular to each other.

3. According to claim 1, the novel decoupled dual-axis elliptical vibration assisted cutting platform is characterized by: The drive unit (3) further comprises two directional constraint beams (3-6) arranged between the amplifying output block and the tool mounting block (6); one end of the two directional constraint beams (3-6) parallel to each other is respectively connected to two positions on the same side of the corresponding amplifying output block via flexible hinges; and the other end of the two directional constraint beams (3-6) parallel to each other is respectively connected to two positions on the same side of the corresponding tool mounting block (6) via flexible hinges.

4. According to claim 3, the novel decoupled dual-axis elliptical vibration assisted cutting platform is characterized in that: The flexible hinges between the swing block (3-2) and the movement constraint block (3-3), between the movement constraint block (3-3) and the amplification output block, between the amplification output block and the direction constraint beam (3-6), and between the direction constraint beam (3-6) and the tool mounting block (6) are semicircular flexible hinges; the hinge thickness of the semicircular flexible hinge is 0.4 mm to 0.8 mm.

5. According to claim 4, the novel decoupled dual-axis elliptical vibration assisted cutting platform is characterized in that: The radius of the semicircular flexible hinge is 1 mm to 2 mm.

6. The novel decoupled dual-axis elliptical vibration assisted cutting platform according to claim 1 is characterized by: The flexible hinges between the pendulum block (3-2) and the corner mounting seat (2) and the middle mounting seat (4) are connected by double parallel straight plate hinges.

7. The novel decoupled dual-axis elliptical vibration assisted cutting platform according to claim 1 is characterized by: The flexible hinge between the amplifying output block and the fixed block (3-5) is connected by a double parallel straight plate hinge.

8. The novel decoupled dual-axis elliptical vibration assisted cutting platform according to claim 1 is characterized by: Two ends of the piezoelectric actuator (3-1) respectively abut against the opposite ends of the pendulum block (3-2) and the fixed block (3-5), and are pre-tightened by bolts.

9. A cutting platform structure optimization method, characterized in that: Used to optimize a new decoupled dual-axis elliptical vibration assisted cutting platform as described in claim 1; the cutting platform structure optimization method is as follows: Construct the stiffness matrix for the first drive unit (3); According to the 90° rotationally symmetrical relative positions between the two drive units (3), the stiffness matrix of the second drive unit (3) is obtained by rotating the stiffness matrix of the first drive unit (3); Using the stiffness matrices corresponding to the two drive units (3) to form a stiffness model of the entire cutting platform; An objective function for structural optimization is established based on the stiffness model, and the structural parameters of the drive unit (3) are adjusted to optimize the overall stiffness of the cutting platform.

10. A cutting control method, characterized in that: Using a novel decoupled dual-axis elliptical vibration assisted cutting platform as described in claim 1; The cutting control method is as follows: two driving units (3) are respectively used as two controlled systems; and the two controlled systems are dynamically controlled by a PID controller according to the displacement error of a tool mounting block (6).

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