Friction-adjustable dual-piezoelectric stick-slip driving platform and method capable of realizing rollback suppression

Abstract

The invention discloses a friction-force-adjustable dual-piezoelectric stick-slip driving platform and method capable of achieving rollback suppression, and belongs to the technical field of micro-driving precision positioning. The platform is mainly composed of a base, a crossed roller guide rail, a working sliding table, a ceramic friction plate, a grating ruler, a grating ruler reading head, a fastening screw and a driving transmission module. A flexible structure in the driving transmission module comprises two symmetrically-distributed variable-rigidity flexible beams, high-consistency bidirectional movement is completed by means of the parasitic movement principle, ordered excitation signals are cooperatively applied to enable contact points to execute an elliptic movement track, and rollback displacement is effectively reduced. The mode of combining initial pre-tightening and dynamic piezoelectric pre-tightening is provided, and friction force self-adaptive adjustment is achieved so as to adapt to different mass loads; large-stroke cross-scale sub-nanometer positioning is realized by adopting a double piezoelectric ceramic driving principle. According to the invention, the design requirement of a large-range and high-precision compatible driver can be met, large-stroke cross-scale sub-nanometer positioning can be realized, the output characteristic is ensured, the overall structure is compact, and the device is suitable for batch production.

Description

Technical Field

[0001] The invention belongs to the technical field of micro-drive precision positioning, and relates to a friction-adjustable dual piezoelectric stick-slip drive platform and a method for achieving backoff suppression. Background Art

[0002] Nanopositioning platforms based on the piezoelectric actuation principle are widely used in high-end equipment in the fields of ultra-precision manufacturing and measurement, automated assembly of micro-nano devices, and fine cell manipulation. These equipment often require precision positioning platforms to have millimeter-level travel, nanometer or sub-nanometer resolution, and the ability to adapt to different loads. In recent years, with the development of piezoelectric technology, actuators with different principles, forms, and structures have emerged. Among them, piezoelectric stick-slip actuators have the advantages of simple structure, large range of motion, high resolution, easy miniaturization, and simple control. They are currently the most widely used type of cross-scale nanopositioning devices.

[0003] Piezoelectric stick-slip actuators use the difference in dynamic and static friction and the slow-fast periodic action of the stator to drive the mover to achieve "stick-slip" stepping motion. However, traditional piezoelectric stick-slip actuators have problems with inconsistent displacement retraction and forward and reverse motion characteristics, which seriously affect the positioning accuracy and output performance of the cross-scale nanopositioning platform, and also cause adverse wear on the mover, thereby reducing the service life and reliability of the actuator. Friction adjustment is a key element in the design and assembly process of piezoelectric stick-slip actuators.

[0004] In 2013, Zhao Hongwei et al. designed a drive unit consisting of a manual precision translation stage and a piezoelectric driver in the patent "Micro-nanoscale stick-slip inertial drive platform with adjustable positive pressure", application number CN201320253409.5, in which the manual precision translation stage can realize the positive pressure adjustment between the piezoelectric driver and the workbench. In 2021, Huang Hu et al. used a flexible drive foot with an integrated strain sensing unit in the patent "Device and method for improving the nonlinearity of large strokes of stick-slip piezoelectric drivers", application number CN202111573861.5, to achieve the control of the maximum contact force between the drive unit and the mobile platform. However, none of the above methods improved the problem of retraction motion.

[0005] In 2022, Yan Peng and others designed a retraction motion suppression module in the patent "A stick-slip actuator and method for actively suppressing retraction motion", application number CN202210879202.2, which uses two piezoelectric ceramic stacks to cooperatively drive the driving foot to separate or compress the mover. However, this design is an asymmetric structure, and it is difficult to ensure the consistency of forward and reverse motion. In 2024, Huang Weiqing and others designed a symmetrical double-flexible hinge structure in the patent "A bidirectional motion stick-slip piezoelectric actuator and driving method", application number CN202410436450.9, which uses two driving feet in parallel and integrated design to meet the driving requirements of small retraction displacement and good bidirectional motion consistency, but this structure is difficult to achieve adaptive adjustment of friction and has a large overall size.

[0006] None of the above methods mentions a friction-adjustable dual piezoelectric stick-slip drive platform and method for achieving backoff suppression. Summary of the invention

[0007] In view of the defects or improvement needs of the prior art, the present invention proposes a stick-slip drive positioning platform with compact structure, adjustable friction, small retraction displacement, good bidirectional motion consistency and high precision, which can meet the requirements of compatibility with large stroke and large scanning range and realize large-stroke cross-scale nanopositioning.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A friction-adjustable dual piezoelectric stick-slip driving platform capable of realizing back-off suppression, the friction-adjustable dual piezoelectric stick-slip driving platform comprises a base 1, two cross roller guides, a working slide 3, a ceramic friction plate 4, a grating ruler 5, a grating ruler reading head 6 and a drive transmission module 8. The two cross roller guides, namely the first cross roller guide 2.1 and the second cross roller guide 2.2, are respectively mounted on the base 1 through the second fastening screw 7.2; the working slide 3 is mounted on the first cross roller guide 2.1 and the second cross roller guide 2.2 through the third fastening screw 7.3; the ceramic friction plate 4 and the grating ruler 5 are respectively mounted on the bottom of the working slide 3; the grating ruler reading head 6 is mounted on the bracket of the base 1 and is located below the working slide 3; the drive transmission module 8 is mounted on the base 1 through the first fastening screw 7.1.

[0010] Furthermore, the base surface of the grating scale reading head 6 is parallel to the base surface of the grating scale 5 .

[0011] Furthermore, the drive transmission module 8 includes a flexible structure, a ceramic drive foot, a large piezoelectric ceramic, a small piezoelectric ceramic, a pre-tightening wedge block, a pre-tightening screw and a strain gauge; specifically:

[0012] The flexible structure includes a first variable stiffness flexible beam 9.1, a second variable stiffness flexible beam 9.2 and a flexible hinge frame 9.3, and the flexible structure is manufactured in an integrated manner; the flexible hinge frame 9.3 is the main structure of the drive transmission module 8; the first variable stiffness flexible beam 9.1 and the second variable stiffness flexible beam 9.2 are symmetrically distributed on the flexible hinge frame 9.3; the first variable stiffness flexible beam 9.1 is located at the upper left of the flexible hinge frame 9.3, and has a groove at the bottom for installing a large piezoelectric ceramic 11.1; the second variable stiffness flexible beam 9.2 is located at the upper right of the flexible hinge frame 9.3, and has a groove at the bottom for installing a large piezoelectric ceramic 11.2; two accommodating grooves are symmetrically distributed on the flexible hinge frame 9.3, which are respectively located directly below the first variable stiffness flexible beam 9.1 and the second variable stiffness flexible beam 9.2, and are used to place large piezoelectric ceramics, small piezoelectric ceramics and pre-tightening wedge blocks.

[0013] The ceramic driving foot comprises two symmetrically distributed first ceramic driving feet 10.1 and second ceramic driving feet 10.2, which are respectively mounted on the bosses at the top ends of the first variable stiffness flexible beam 9.1 and the second variable stiffness flexible beam 9.2.

[0014] The large piezoelectric ceramics include a first large piezoelectric ceramic 11.1 and a second large piezoelectric ceramic 11.2, the small piezoelectric ceramics include a first small piezoelectric ceramic 12.1 and a second small piezoelectric ceramic 12.2, the pre-tightening wedge block includes a first pre-tightening wedge block 13.1 and a second pre-tightening wedge block 13.2, the pre-tightening screw includes a first pre-tightening screw 14.1 and a second pre-tightening screw 14.2, and the strain gauge includes a first group of strain gauges 15.1 and a second group of strain gauges 15.2.

[0015] There are two pre-tightening wedge blocks, a first pre-tightening wedge block 13.1 and a second pre-tightening wedge block 13.2. The first pre-tightening wedge block 13.1 is installed at the bottom of the left receiving groove of the flexible hinge frame through a first pre-tightening screw 14.1; symmetrically, the second pre-tightening wedge block 13.2 is installed at the bottom of the right receiving groove of the flexible hinge frame through a pre-tightening screw 14.2; each pre-tightening wedge block is composed of a bottom active wedge block and a top driven wedge block, wherein the driven wedge block has a groove for installing a small piezoelectric ceramic.

[0016] The first large piezoelectric ceramic 11.1 and the first small piezoelectric ceramic 12.1 are structurally connected in series to form a positive driving source, which is installed in a mounting groove formed by the top groove of the driven wedge block in the first pre-tightening wedge block 13.1 and the bottom groove of the first variable stiffness flexible beam 9.1; symmetrically, the second large piezoelectric ceramic 11.2 and the second small piezoelectric ceramic 12.2 are structurally connected in series to form a negative driving source, which is installed in a mounting groove formed by the top groove of the driven wedge block in the second pre-tightening wedge block 13.2 and the bottom groove of the second variable stiffness flexible beam 9.2; the two large piezoelectric ceramics and the two small piezoelectric ceramics are connected to the driving power supply through wires.

[0017] The first group of strain gauges 15.1 and the second group of strain gauges 15.2 are arranged symmetrically, and each group of strain gauges consists of four strain gauges, which are respectively attached to the first variable stiffness flexible beam 9.1 and the second variable stiffness flexible beam 9.2. As the first and second ceramic driving feet 10.1 and 10.2 move, the corresponding first and second groups of strain gauges 15.1 and 15.2 are deformed together with the first and second variable stiffness flexible beams 9.1 and 9.2; the full-bridge Wheatstone bridge composed of each group of strain gauges converts resistance changes into voltage changes, thereby characterizing the contact force between the ceramic driving foot and the ceramic friction plate.

[0018] Furthermore, the grating ruler 5 and the grating ruler reading head 6 constitute a sensing unit of a position feedback system, and cooperate with the control system to realize closed-loop feedback to ensure positioning accuracy.

[0019] Furthermore, the first group of strain gauges 15.1 and the second group of strain gauges 15.2 are covered with a protective layer to reduce noise interference.

[0020] A dual piezoelectric stick-slip driving method with adjustable friction that can achieve retraction suppression is implemented based on the above-mentioned dual piezoelectric stick-slip driving platform with adjustable friction that can achieve retraction suppression. The two symmetrically distributed variable stiffness flexible beams of the flexible structure in the drive transmission module use the principle of parasitic motion to complete highly consistent bidirectional motion, and apply an ordered excitation signal to make the contact point execute an elliptical motion trajectory, effectively reducing the retraction displacement. The present invention proposes a combination of initial preload and dynamic piezoelectric preload to achieve adaptive adjustment of friction to adapt to different mass loads; and adopts a dual piezoelectric ceramic drive principle to achieve large-stroke cross-scale sub-nanometer positioning. Specifically, it includes the following steps:

[0021] In the first step, the active wedge block in the pre-tightening wedge block is pushed to move by rotating the pre-tightening screw, thereby pushing the driven wedge block in contact with the active wedge block to move, so as to achieve the initial pre-tightening of the large piezoelectric ceramics and the small piezoelectric ceramics.

[0022] In the second step, different weights are placed on the working slide 3 as loads of known weight, and forward stepping mode driving and reverse stepping mode driving are realized. The voltage difference between the two ends of the Wheatstone bridge composed of each set of strain gauges is collected to generate a load-pressure difference calibration curve; this curve is used to determine the constant initial voltage U of the forward drive source 1_initial and the constant initial voltage U of the negative driving source 2_initial , to ensure the consistency of the friction between the first and second variable stiffness flexible beams 9.1, 9.2 and the working slide 3, thereby improving the working performance of the positioning platform under different loads.

[0023] The third step is to select the excitation signal to be applied according to the driving direction.

[0024] Furthermore, the present invention can realize a friction-adjustable dual piezoelectric stick-slip drive platform with retraction suppression. When the dual piezoelectric ceramic drive principle is in operation, the small piezoelectric ceramic completes stepping mode drive under the excitation of a periodic symmetrical voltage signal to achieve coarse positioning; the large piezoelectric ceramic slowly extends under the excitation of a slowly rising sawtooth voltage signal to complete scanning mode drive and achieve fine positioning. At the same time, it can provide auxiliary preload forces under different constant initial voltages for loads of different masses.

[0025] Furthermore, the specific steps of the forward stepping mode drive are as follows:

[0026] Step 1: Apply the constant initial voltage U determined in the second step to the first large piezoelectric ceramic 11.1 1_initial , so that it provides auxiliary preload force to ensure that the first ceramic driving foot 10.1 is in contact with the ceramic friction plate 4, and the contact point is P1.

[0027] Step 2: Apply a periodic symmetrical voltage signal u to the first small piezoelectric ceramic 12.1 1_step ; Symmetrical voltage signal u at the initial moment 1_step The voltage value is 0, and the first small piezoelectric ceramic 12.1 is at a natural length; in the voltage gradually rising stage, the first small piezoelectric ceramic 12.1 is extended, and the friction force between the contact point P1 and the ceramic friction plate 4 is the static friction force f s1 Driven by the first variable stiffness flexible beam 9.1, the contact point P1 generates displacements along the positive direction of the horizontal axis and the positive direction of the vertical axis, and the working slide 3 moves along the positive direction of the horizontal axis. At the same time, the displacement of the contact point P1 along the positive direction of the vertical axis increases the contact force F between the first ceramic driving foot 10.1 and the ceramic friction plate 4. c1 , within a certain range, the greater the contact force, the greater the output force; in the stage where the voltage gradually decreases, the first small piezoelectric ceramic 12.1 is shortened, and the friction force between the contact point P1 and the ceramic friction plate 4 is the dynamic friction force f d1 , the contact point P1 is driven by the first variable stiffness flexible beam 9.1 to produce a displacement along the negative horizontal axis and the negative vertical axis, and the contact force F c1 Reduced, while the dynamic friction f d1 The retraction displacement is reduced to a certain extent; within one excitation signal cycle, the motion trajectory of the contact point P1 is approximately an ellipse.

[0028] Step 3: In the above symmetrical voltage signal u 1_step In the voltage drop stage, a sawtooth wave back-off suppression voltage U is applied to the second largest piezoelectric ceramic 11.2. 2_suppression , further reducing the back-off displacement.

[0029] Furthermore, the reverse stepping mode driving step is similar to the forward stepping mode driving step.

[0030] Furthermore, the scanning mode drive is executed after the stepping mode drive; during the scanning mode drive, the small piezoelectric ceramic does not stretch, and the large piezoelectric ceramic slowly stretches under the action of the slowly rising sawtooth wave voltage, driving the working slide 3 to move slowly in the horizontal axis direction to complete precise positioning.

[0031] The beneficial effects of the present invention are:

[0032] (1) The present invention designs two symmetrically distributed variable stiffness flexible beams on the flexible hinge frame, which improves the ability to suppress the retreating motion while ensuring the consistency of the forward and reverse motions.

[0033] (2) The present invention proposes an auxiliary preload adaptive control strategy based on strain gauges, which can realize friction force adjustment for different loads and ensure output characteristics.

[0034] (3) The present invention adopts the dual piezoelectric ceramic driving principle, which can meet the design requirements of a driver with large range and high precision compatibility, and realize large-stroke cross-scale sub-nanometer positioning.

[0035] (4) The present invention integrates a position feedback sensor unit, and the overall structure is compact, which is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0037] Figure 2 The following is a schematic diagram of the connections of each component;

[0038] Figure 3 It is a schematic diagram of the structure of the drive transmission module;

[0039] Figure 4 It is a schematic diagram of the voltage signal and working status at the initial moment in the forward stepping mode driving; Figure 4 (a) is a schematic diagram of the working state of the first variable stiffness flexible beam 9.1 at the initial moment in the forward stepping mode driving;

[0040] Figure 4 (b) is a schematic diagram of the motion trajectory and voltage signal at the initial moment in the forward stepping mode drive; Figure 4The upper left figure in (b) is a schematic diagram of the motion trajectory of the contact point P1, with its horizontal axis being the displacement in the horizontal axis direction and its vertical axis being the displacement in the vertical axis direction; the middle left figure is a schematic diagram of the voltage signal of the large piezoelectric ceramic 11.1, with its horizontal axis being time and its vertical axis being voltage value; the lower left figure is a schematic diagram of the voltage signal of the small piezoelectric ceramic 12.1, with its horizontal axis being time and its vertical axis being voltage value; the upper right figure is a schematic diagram of the voltage signal of the large piezoelectric ceramic 11.2, with its horizontal axis being time and its vertical axis being voltage value; the lower right figure is a schematic diagram of the voltage signal of the small piezoelectric ceramic 12.2, with its horizontal axis being time and its vertical axis being voltage value;

[0041] Figure 5 It is a schematic diagram of the voltage signal and working status in the voltage gradually rising stage in the forward stepping mode driving; Figure 5 (a) is a schematic diagram of the working state of the first variable stiffness flexible beam 9.1 during the voltage gradually rising stage in the forward stepping mode driving; Figure 5 (b) is a schematic diagram of the motion trajectory and voltage signal during the voltage gradually rising stage in the forward stepping mode drive; Figure 5 The coordinate axes in (b) are defined as Figure 4 (b) are the same;

[0042] Figure 6 It is a schematic diagram of the voltage signal and working status in the voltage drop stage in the forward stepping mode drive; Figure 6 (a) is a schematic diagram of the working state of the first variable stiffness flexible beam 9.1 during the voltage drop stage in the forward stepping mode driving; Figure 6 (b) is a schematic diagram of the motion trajectory and voltage signal during the voltage drop phase in the forward stepping mode drive; Figure 6 The coordinate axes in (b) are defined as Figure 4 (b) are the same;

[0043] Figure 7 It is a schematic diagram of the voltage signal and working status in the forward scanning mode drive; Figure 7 (a) is a schematic diagram of the working state of the first variable stiffness flexible beam 9.1 in the forward scanning mode drive; Figure 7 (b) is a schematic diagram of the motion trajectory and voltage signal in the forward scanning mode drive; Figure 7 The coordinate axes in (b) are defined as Figure 4 (b) The same. DETAILED DESCRIPTION

[0044] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings and technical solutions.

[0045] In this embodiment, the overall structure of the friction-adjustable dual piezoelectric stick-slip driving platform that can achieve back-off suppression is as follows: Figure 1As shown, the overall length is 87mm, the width is 60mm, and the height is 62mm; the guide rail length is 75mm; the base 1, the working slide 3 and the flexible structure are processed with 7075 aluminum alloy material, and the first and second variable stiffness flexible beams 9.1, 9.2 and the flexible hinge frame 9.3 in the flexible structure are processed into one body; after the flexible structure is processed, the first group of strain gauges 15.1 and the second group of strain gauges 15.2 are respectively attached to the first and second variable stiffness flexible beams 9.1 and 9.2, and a protective layer is covered on the strain gauges to reduce noise interference; the nominal displacements of the first and second largest piezoelectric ceramics 11.1 and 11.2 are 15μm, and the nominal displacements of the first and second smallest piezoelectric ceramics 12.1 and 12.2 are 6.5μm.

[0046] like Figure 2 As shown, the connection and installation process of each component is as follows:

[0047] The first step, such as Figure 3 As shown, the first large piezoelectric ceramic 11.1 and the first small piezoelectric ceramic 12.1 are connected in series in structure and installed in the installation groove formed by the top groove of the driven wedge block in the first preloaded wedge block 13.1 and the bottom groove of the first variable stiffness flexible beam 9.1; symmetrically, the second large piezoelectric ceramic 11.2 and the second small piezoelectric ceramic 12.2 are connected in series in structure and installed in the installation grooves on the second preloaded wedge block 13.2 and the second variable stiffness flexible beam 9.2; the two large piezoelectric ceramics and the two small piezoelectric ceramics are connected to the driving power supply through wires;

[0048] In the second step, the drive transmission module 8 is mounted on the base 1 through the first fastening screw 7.1; the grating scale reading head 6 is mounted on the bracket of the base 1; the first and second cross roller guide rails 2.1 and 2.2 are respectively mounted on the base 1 through the second fastening screw 7.2;

[0049] The third step is to install the ceramic friction plate 4 and the grating ruler 5 at the bottom of the working slide 3 respectively; the working slide 3 is installed on the first and second cross roller guide rails 2.1 and 2.2 by the third fastening screws 7.3;

[0050] The fourth step is to rotate the first and second pre-tightening screws 14.1 and 14.2 to push the active wedges in the corresponding first and second pre-tightening wedge blocks 13.1 and 13.2 to move, thereby pushing the driven wedges in contact with the active wedges to move, so as to achieve the initial pre-tightening of the two large piezoelectric ceramics and the two small piezoelectric ceramics; then, different weights are placed on the working slide 3 as loads of known weight, and the voltage difference between the two ends of the Wheatstone bridge composed of each set of strain gauges is collected to generate a load-pressure difference calibration curve; this curve is used to determine the constant initial voltage U of the forward drive source. 1_initial and the constant initial voltage U of the negative driving source 2_initial, to ensure the consistency of the friction between the first and second variable stiffness flexible beams 9.1, 9.2 and the working slide 3, thereby improving the working performance of the positioning platform under different loads;

[0051] The fifth step is to install the front and rear baffles of the stick-slip drive platform to provide protection.

[0052] In this embodiment, the friction-adjustable dual piezoelectric stick-slip drive platform that can achieve retraction suppression adopts the dual piezoelectric ceramic drive principle when working, wherein the first and second small piezoelectric ceramics 12.1 and 12.2 complete stepping mode drive under the excitation of periodic symmetrical voltage signals to achieve coarse positioning; the first and second large piezoelectric ceramics 11.1 and 11.2 slowly extend under the excitation of the slowly rising sawtooth voltage signal to complete scanning mode drive to achieve fine positioning, and at the same time, can provide auxiliary preload forces under different constant initial voltages for loads of different masses.

[0053] In this embodiment, the load is a weight with a mass of 35g, and the forward stepping mode drive and scanning mode drive are performed. The voltage signal and working state of the forward movement are as follows: Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, the execution process is as follows:

[0054] First, a forward stepping mode drive is performed to apply a constant initial voltage U to the first large piezoelectric ceramic 11.1. 1_initial , the voltage value is 8V, so that it provides auxiliary preload force to ensure that the first ceramic driving foot 10.1 is in contact with the ceramic friction plate 4, and the contact point is P1; due to the existence of processing errors, a different constant initial voltage U is applied to the second largest piezoelectric ceramic 11.2 2_initial , the voltage value is 12V, so that the second ceramic driving foot 10.2 contacts the ceramic friction plate 4, and the contact point is P2;

[0055] Then, a periodic symmetrical voltage signal u is applied to the first small piezoelectric ceramic 12.1. 1_step , the maximum voltage value is 90V;

[0056] Symmetrical voltage signal u at the initial moment 1_step The voltage value is 0, and the first small piezoelectric ceramic 12.1 is at a natural length, such as Figure 4 As shown;

[0057] The voltage gradually rises, such as Figure 5 As shown, the first small piezoelectric ceramic 12.1 is stretched, and the friction force between the contact point P1 and the ceramic friction plate 4 is the static friction force f s1Driven by the variable stiffness flexible beam 9.1, the contact point P1 produces displacements along the positive direction of the horizontal axis and the positive direction of the vertical axis, and the working slide 3 moves along the positive direction of the horizontal axis. At the same time, the displacement of the contact point P1 along the positive direction of the vertical axis increases the contact force F between the ceramic driving foot 10.1 and the ceramic friction plate 4. c1 , within a certain range, the greater the contact force, the greater the output force;

[0058] The voltage gradually decreases, such as Figure 6 As shown, the first small piezoelectric ceramic 12.1 is shortened, and the friction force between the contact point P1 and the ceramic friction plate 4 is the dynamic friction force f d1 , the contact point P1 is driven by the first variable stiffness flexible beam 9.1 to produce a displacement along the negative horizontal axis and the negative vertical axis, and the contact force F c1 Reduced, while the dynamic friction f d1 The retraction displacement is reduced to a certain extent; within one excitation signal cycle, the motion trajectory of the contact point P1 is approximately an ellipse; in this stage, a sawtooth wave retraction suppression voltage U is applied to the second largest piezoelectric ceramic 11.2. 2_suppression , the maximum voltage value is 64V, further reducing the retreat displacement;

[0059] Finally, the forward scanning mode is performed, and the first large piezoelectric ceramic 11.1 is driven by a slowly rising sawtooth voltage U 1_scan Under the action of the pulley, it slowly extends, driving the working slide 3 to move slowly in the horizontal axis direction to complete the precise positioning.

[0060] In this embodiment, the voltage signal and execution process of the reverse motion are as follows:

[0061] First, a reverse stepping mode drive is performed to apply a constant initial voltage U to the second largest piezoelectric ceramic 11.2. 2_initial , the voltage value is 12V, so that it provides auxiliary preload force to ensure that the second ceramic drive foot 10.2 is in contact with the ceramic friction plate 4, and the contact point is P2; a constant initial voltage U is applied to the first large piezoelectric ceramic 11.1 1_initial , the voltage value is 8V, so that the second ceramic driving foot 10.1 contacts the ceramic friction plate 4, and the contact point is P1;

[0062] Then, a periodic symmetrical voltage signal u is applied to the second small piezoelectric ceramic 12.2. 2_step , the maximum voltage value is 90V;

[0063] Symmetrical voltage signal u at the initial moment 2_step The voltage value is 0, and the second smallest piezoelectric ceramic 12.2 is at a natural length;

[0064] In the voltage gradually rising stage, the second smallest piezoelectric ceramic 12.2 stretches, and the friction force between the contact point P2 and the ceramic friction plate 4 is the static friction force fs2 Driven by the second variable stiffness flexible beam 9.2, the contact point P2 generates displacement along the negative direction of the horizontal axis and the positive direction of the vertical axis, and the working slide 3 moves along the negative direction of the horizontal axis. At the same time, the displacement of the contact point P2 along the positive direction of the vertical axis increases the contact force F between the ceramic driving foot 10.2 and the ceramic friction plate 4. c2 , within a certain range, the greater the contact force, the greater the output force;

[0065] In the stage of voltage gradually decreasing, the second smallest piezoelectric ceramic 12.2 is shortened, and the friction force between the contact point P2 and the ceramic friction plate 4 is the dynamic friction force f d2 , the contact point P2 is driven by the second variable stiffness flexible beam 9.2 to produce displacement along the positive horizontal axis and the negative vertical axis, and the contact force F c2 Reduced, while the dynamic friction f d2 The retraction displacement is reduced to a certain extent; within one excitation signal cycle, the motion trajectory of the contact point P2 is approximately an ellipse; in this stage, a sawtooth wave retraction suppression voltage U is applied to the first large piezoelectric ceramic 11.1. 1_suppression , the maximum voltage value is 67V, further reducing the retreat displacement;

[0066] Finally, the forward scanning mode is performed, and the first large piezoelectric ceramic 11.1 is driven by a slowly rising sawtooth voltage U 2_scan It slowly extends under the action, driving the working slide 3 to move slowly in the horizontal axis direction to complete the precise positioning.

[0067] In summary, the present invention proposes a dual piezoelectric stick-slip drive platform with adjustable friction force that can achieve retraction suppression, which realizes adaptive adjustment of friction force, has the ability to suppress retraction, has good bidirectional motion consistency, is easy to process and assemble, reduces assembly errors, effectively improves the output performance of the stick-slip drive positioning platform, ensures the motion accuracy of the stick-slip drive positioning platform, is suitable for mass production, and is suitable for application in various fields with structural miniaturization and large-scale precise positioning requirements, such as micro-nano operations, micro-robots, and biological micro-operations.

[0068] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A friction-adjustable dual piezoelectric stick-slip drive platform capable of achieving backoff suppression, characterized in that: The friction-adjustable dual piezoelectric stick-slip driving platform comprises a base (1), a first cross roller guide (2.1), a second cross roller guide (2.2), a working slide (3), a ceramic friction plate (4), a grating scale (5), a grating scale reading head (6) and a drive transmission module (8); the first cross roller guide (2.1) and the second cross roller guide (2.2) are mounted on the base (1); the working slide (3) is mounted on the first cross roller guide ( 2.1) and the second cross roller guide rail (2.2); the ceramic friction plate (4) and the grating ruler (5) are respectively installed at the bottom of the working slide (3); the grating ruler reading head (6) is installed on the bracket of the base (1) and is located below the working slide (3), the base surface of the grating ruler reading head (6) is parallel to the base surface of the grating ruler (5), and the grating ruler (5) and the grating ruler reading head (6) constitute a sensing unit; the drive transmission module (8) is installed on the base (1).

2. The friction-adjustable dual piezoelectric stick-slip driving platform capable of achieving backoff suppression according to claim 1, characterized in that: The drive transmission module (8) comprises a flexible structure, a ceramic drive foot, a large piezoelectric ceramic, a small piezoelectric ceramic, a preloaded wedge block and a strain gauge; specifically: The flexible structure comprises a first variable stiffness flexible beam (9.1), a second variable stiffness flexible beam (9.2) and a flexible hinge frame (9.3), and the flexible structure is manufactured in an integrated manner; the flexible hinge frame (9.3) is the main structure of the drive transmission module (8); the first variable stiffness flexible beam (9.1) and the second variable stiffness flexible beam (9.2) are symmetrically distributed on the flexible hinge frame (9.3); two accommodating grooves are symmetrically distributed on the flexible hinge frame (9.3), which are respectively located below the first variable stiffness flexible beam (9.1) and the second variable stiffness flexible beam (9.2), and are used to place large piezoelectric ceramics, small piezoelectric ceramics and pre-tightened wedge blocks; The ceramic driving foot comprises two symmetrically distributed first ceramic driving feet (10.1) and second ceramic driving feet (10.2), which are respectively mounted on the top of the first variable stiffness flexible beam (9.1) and the second variable stiffness flexible beam (9.2); The large piezoelectric ceramic comprises a first large piezoelectric ceramic (11.1) and a second large piezoelectric ceramic (11.2); the small piezoelectric ceramic comprises a first small piezoelectric ceramic (12.1) and a second small piezoelectric ceramic (12.2); the preloaded wedge block comprises a first preloaded wedge block (13.1) and a second preloaded wedge block (13.2); and the strain gauge comprises a first group of strain gauges (15.1) and a second group of strain gauges (15.2); The first pre-tightening wedge block (13.1) is installed at the bottom of the left receiving groove of the flexible hinge frame; symmetrically, the second pre-tightening wedge block (13.2) is installed at the bottom of the right receiving groove of the flexible hinge frame; The first large piezoelectric ceramic (11.1) and the first small piezoelectric ceramic (12.1) are structurally connected in series to form a positive driving source, which is installed in a mounting groove formed by a first preloaded wedge block (13.1) and a first variable stiffness flexible beam (9.1); symmetrically, the second large piezoelectric ceramic (11.2) and the second small piezoelectric ceramic (12.2) are structurally connected in series to form a negative driving source, which is installed in a mounting groove formed by a second preloaded wedge block (13.2) and a second variable stiffness flexible beam (9.2); the two large piezoelectric ceramics and the two small piezoelectric ceramics are connected to the driving power source via wires; The first group of strain gauges (15.1) and the second group of strain gauges (15.2) are symmetrically arranged on the first variable stiffness flexible beam (9.1) and the second variable stiffness flexible beam (9.2) and are used to characterize the contact force between the ceramic driving foot and the ceramic friction plate.

3. The friction-adjustable dual piezoelectric stick-slip driving platform capable of achieving backoff suppression according to claim 2, characterized in that: The first group of strain gauges (15.1) and the second group of strain gauges (15.2) are both composed of four strain gauges, which are respectively attached to the first variable stiffness flexible beam (9.1) and the second variable stiffness flexible beam (9.2). With the movement of the first and second ceramic driving feet (10.1) and (10.2), the corresponding first and second groups of strain gauges (15.1) and (15.2) are deformed along with the first and second variable stiffness flexible beams (9.1) and (9.2); the full-bridge Wheatstone bridge composed of each group of strain gauges converts resistance changes into voltage changes, indicating the contact force between the ceramic driving foot and the ceramic friction plate.

4. The friction-adjustable dual piezoelectric stick-slip driving platform capable of achieving backoff suppression according to claim 2, characterized in that: The positive driving source is installed in a mounting groove formed by the top groove of the driven wedge block in the first preloaded wedge block (13.1) and the bottom groove of the first variable stiffness flexible beam (9.1); the negative driving source is installed in a mounting groove formed by the top groove of the driven wedge block in the second preloaded wedge block (13.2) and the bottom groove of the second variable stiffness flexible beam (9.2).

5. The friction-adjustable dual piezoelectric stick-slip driving platform capable of achieving backoff suppression according to claim 2, characterized in that: In the flexible structure, the first variable stiffness flexible beam (9.1) is located at the upper left of the flexible hinge frame (9.3), and has a groove at the bottom for installing a large piezoelectric ceramic (11.1); the second variable stiffness flexible beam (9.2) is located at the upper right of the flexible hinge frame (9.3), and has a groove at the bottom for installing a large piezoelectric ceramic (11.2).

6. The friction-adjustable dual piezoelectric stick-slip driving platform capable of achieving backoff suppression according to claim 2, characterized in that: Each preload wedge block consists of a bottom active wedge block and a top driven wedge block, wherein the driven wedge block has a groove for mounting a small piezoelectric ceramic.

7. A friction-adjustable dual piezoelectric stick-slip driving method capable of achieving backoff suppression, characterized in that: The friction-adjustable dual piezoelectric stick-slip driving method is implemented based on the friction-adjustable dual piezoelectric stick-slip driving platform capable of achieving backoff suppression as described in any one of claims 1 to 6, and comprises the following steps: The first step is to push the active wedge block in the preloaded wedge block to move, thereby pushing the driven wedge block in contact with the active wedge block to move, thereby achieving the initial preload of the large piezoelectric ceramic and the small piezoelectric ceramic; In the second step, different weights are placed on the working slide (3) as loads of known weight, and forward stepping mode driving and reverse stepping mode driving are implemented. The voltage difference between the two ends of the Wheatstone bridge composed of each set of strain gauges is collected to generate a load-pressure difference calibration curve; the load-pressure difference calibration curve is used to determine the constant initial voltage U of the forward driving source. 1_initial and the constant initial voltage U of the negative driving source 2_initial , ensuring the consistency of the friction force between the first and second variable stiffness flexible beams (9.1), (9.2) and the working slide (3); The third step is to select the excitation signal to be applied according to the driving direction.

8. The friction-adjustable dual piezoelectric stick-slip driving method capable of achieving backoff suppression according to claim 7, characterized in that: When the friction-adjustable dual piezoelectric stick-slip drive platform capable of achieving retreat suppression is working, dual piezoelectric ceramic drive is adopted, wherein the small piezoelectric ceramic completes stepping mode drive under the excitation of a periodic symmetrical voltage signal to achieve coarse positioning; the large piezoelectric ceramic slowly extends under the excitation of a slowly rising sawtooth voltage signal to complete scanning mode drive to achieve fine positioning; and at the same time, auxiliary preload forces under different constant initial voltages are provided for loads of different masses.

9. The friction-adjustable dual piezoelectric stick-slip driving method capable of achieving backoff suppression according to claim 7, characterized in that: The specific steps of forward stepping mode driving are as follows: Step 1: Apply the constant initial voltage U determined in the second step to the first large piezoelectric ceramic (11.1) 1_initial , providing auxiliary preload force to ensure that the first ceramic driving foot (10.1) is in contact with the ceramic friction plate (4), with the contact point being P1; Step 2: Apply a periodic symmetrical voltage signal u to the first small piezoelectric ceramic (12.1) 1_step Specific: Symmetrical voltage signal u at the initial moment 1_step The voltage value is 0, and the first small piezoelectric ceramic (12.1) is at a natural length; In the voltage gradually rising stage, the first small piezoelectric ceramic (12.1) stretches, and the friction force between the contact point P1 and the ceramic friction plate (4) is the static friction force f s1 The contact point P1 is displaced by the first variable stiffness flexible beam (9.1), and the working slide (3) moves in the positive direction along the horizontal axis. At the same time, the displacement of the contact point P1 in the positive direction along the vertical axis increases the contact force F between the first ceramic driving foot (10.1) and the ceramic friction plate (4). c1 ; In the stage of voltage gradually decreasing, the first small piezoelectric ceramic (12.1) is shortened, and the friction force between the contact point P1 and the ceramic friction plate (4) is the dynamic friction force f d1 , the contact point P1 is displaced by the first variable stiffness flexible beam (9.1), and the contact force F c1 Reduced, while the dynamic friction f d1 Reduce, reduce the retreat displacement; In one excitation signal cycle, the contact point P1 executes an elliptical motion trajectory; Step 3: In the symmetrical voltage signal u 1_step In the voltage drop stage, a sawtooth wave back-off suppression voltage U is applied to the second largest piezoelectric ceramic (11.2). 2_suppression , further reducing the retreat displacement; The reverse stepping mode driving steps are the same as the forward stepping mode driving steps.

10. The friction-adjustable dual piezoelectric stick-slip driving method capable of achieving backoff suppression according to claim 7, characterized in that: The scanning mode drive is executed after the stepping mode drive; during the scanning mode drive, the small piezoelectric ceramic does not extend, and the large piezoelectric ceramic slowly extends, driving the working slide (3) to move in the horizontal axis direction to complete the precise positioning.

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