A dual piezoelectric driving high amplification ratio variable clamping force micro-nano clamping device

Abstract

This invention relates to a high-amplitude, variable-force micro / nano clamping device driven by dual piezoelectric actuators. The amplification base's amplification frame includes a fixed base, a connecting hinge, and a support. Two amplification lever arms are disposed on both sides of the amplification frame, with the inner force-bearing ends of the horizontal arms connected to the corresponding ends of the support and the fixed base via connecting hinges on their respective sides. The lower ends of the clamping arms on both sides of the clamping unit are connected to the upper ends of the corresponding vertical arms. Two piezoelectric ceramic units are arranged side-by-side within the piezoelectric frame. A lever hinge is provided on the vertical arm of each amplification lever arm, and the lower ends of the connecting parts on both sides of the piezoelectric frame are hinged to the corresponding lever hinges. This invention effectively achieves large displacement output from micrometer-level displacement of the piezoelectric ceramic units to the ends of the clamping arms, significantly reduces the capacitive load of the piezoelectric actuator, effectively improves the bandwidth and dynamic response performance of the drive circuit, and allows for flexible replacement of the clamping arms.

Description

Technical Field

[0001] This invention relates to the field of micro-nano manipulation, specifically a high-amplitude variable clamping force micro-nano clamping device driven by dual piezoelectric actuators. Background Technology

[0002] Micro-nano manipulation technology plays a crucial role in high-precision fields such as microelectronics manufacturing, biomedical engineering, and nanomaterial assembly. As the feature size of integrated circuits continues to shrink, the demands for dynamic microscale manipulation of cells or biological tissues in biomedicine increase, and the precision of nanomaterial manufacturing and manipulation continues to improve, research and industry are placing even more stringent technical requirements on micro-nano manipulation devices.

[0003] In existing technologies, piezoelectric ceramic actuation has become the most commonly used actuation method for micro / nano grippers due to its advantages such as fast response, high displacement accuracy, high stiffness, and strong driving force. However, this method has the following drawbacks:

[0004] I. Existing micro / nano grippers typically employ a single-stage flexible mechanism or a single lever amplification mechanism for displacement amplification, resulting in a relatively low overall amplification factor (usually not exceeding 5 times). In micro / nano-scale manipulation, the output displacement of piezoelectric ceramics is generally only at the micrometer or even sub-micrometer level, insufficient for effective gripping and control. Therefore, to achieve larger displacement output, traditional solutions usually require the use of larger-sized, higher-voltage piezoelectric ceramics or multiple piezoelectric ceramics connected in series. This not only increases the capacitive load and reduces the dynamic response speed but also increases the overall complexity and size of the device, making it difficult to meet the requirements of miniaturization and integration.

[0005] Second, piezoelectric ceramics, when used as driving units, exhibit capacitive load effects, which become a significant bottleneck severely restricting the improvement of high dynamic performance in micro-nano manipulation systems. When the capacitance of the piezoelectric ceramic is large (e.g., exceeding 1μF or even higher), the capacitive load driven by the high-voltage amplifier circuit increases dramatically, and the capacitive reactance decreases rapidly with increasing frequency. This leads to a sharp increase in the instantaneous current output by the high-voltage driving circuit, resulting in significant thermal effects and power losses. Consequently, the dynamic response bandwidth and stability of the system are significantly reduced, making it difficult to meet the requirements of rapid and precise clamping and dynamic response. For example, in microelectronic assembly, grippers need to rapidly grasp and release tiny electronic components at high frequencies of tens of kilohertz. Similarly, in the biomedical field, real-time dynamic adjustment of clamping force is required for the capture, release, and precise mechanical measurement of cell or tissue samples. Currently, in these high-frequency manipulation scenarios, the sharp decrease in capacitive reactance caused by the capacitive load of the piezoelectric ceramic results in extremely high instantaneous current demands on the amplifier, leading to lag in output voltage response, severe signal distortion, reduced amplifier efficiency, and potentially even excessive heat loss in the amplifier, damaging the equipment. Existing technologies typically compromise by increasing amplifier power, using more expensive high-current drive chips, or reducing the operating frequency. This increases equipment costs and makes it difficult to meet the operational requirements of practical applications.

[0006] Third, most existing micro / nano grippers are designed for a single, specific application scenario, such as rigid grippers designed solely for high clamping forces or low-rigidity grippers designed only for flexible clamping. This single-function design prevents existing grippers from quickly and flexibly adapting to various application scenarios. For example, grippers with high clamping forces generally have high rigidity, making it difficult to achieve precise control of small clamping forces; while precision grippers with small clamping forces generally employ lower rigidity structures, making it difficult to achieve large clamping forces and lacking real-time force feedback control. This singularity often necessitates redesigning and remanufacturing the structure for different objects being clamped in practical engineering applications, resulting in high costs, low efficiency, and severely limiting the versatility and ease of engineering application of grippers.

[0007] Therefore, in summary, there is an urgent need to develop a novel micro / nano gripper with a simple and compact structure, high amplification ratio, effective reduction of piezoelectric actuator load, significant improvement of control bandwidth, and flexible and variable clamping force, in order to overcome the above-mentioned bottlenecks and meet the comprehensive performance requirements of micro / nano manipulation devices in high-end application fields such as microelectronics manufacturing, biomedical experiments, and nanotechnology. Summary of the Invention

[0008] The purpose of this invention is to provide a high-amplification-ratio variable clamping force micro / nano clamping device with dual piezoelectric drive, which can effectively realize the micron-level displacement of the piezoelectric ceramic unit to the large displacement output at the end of the clamping arm, and can significantly reduce the capacitive load of the piezoelectric actuator, effectively improve the bandwidth and dynamic response performance of the drive circuit, and can flexibly replace the clamping arm according to actual needs.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A high-amplitude variable clamping force micro / nano clamping device driven by dual piezoelectric actuators includes a clamping unit, a piezoelectric ceramic unit, and an amplification base. The amplification base includes a piezoelectric frame, an amplification frame, and amplification lever arms. The amplification frame includes a fixed base, a connecting hinge portion, and a support portion. Two amplification lever arms are respectively disposed on both sides of the amplification frame, and each amplification lever arm includes a horizontal arm and a vertical arm arranged in an L-shape. One side of the force-bearing end of the inner side of the horizontal arm is connected to the corresponding end of the support portion through the corresponding connecting hinge portion, and the other side is connected to the corresponding end of the fixed base through the corresponding connecting hinge portion. The clamping unit includes clamping arms on both sides, and the lower end of the clamping arm is connected to the upper end of the corresponding vertical arm. The piezoelectric frame is concave and includes connecting portions on both sides and a limiting portion in the middle. Two piezoelectric ceramic units are arranged side by side in the piezoelectric frame and are located between the limiting portion and the support portion of the amplification frame. The vertical arm is provided with a lever hinge portion, and the lower ends of the connecting portions on both sides of the piezoelectric frame are respectively hinged to the lever hinge portions on the corresponding sides.

[0011] The force-bearing end on the inner side of the horizontal arm and the connecting hinge parts on both sides form a triangular structure. The connecting hinge parts are provided with multiple circular notches, and the circular notches form hinge parts that generate elastic deformation.

[0012] The upper end of the vertical arm of the amplifying lever arm is provided with a connecting block, and the connecting block is fixedly connected to the lower end of the corresponding side clamping arm by fixing screws.

[0013] The base of the magnifying frame is provided with base fixing holes.

[0014] The limiting part of the piezoelectric frame is provided with threaded holes for fixing the piezoelectric ceramic unit.

[0015] The piezoelectric ceramic unit includes a piezoelectric housing, and piezoelectric ceramic sheets and electrode layers are arranged alternately along the length direction inside the piezoelectric housing. The upper end of the piezoelectric housing is provided with positive electrode leads and negative electrode leads connected to the piezoelectric actuator. In addition, the upper end of the piezoelectric housing is provided with an insulating top cover that contacts the limiting part of the piezoelectric frame, and the lower end is provided with an insulating bottom cover that contacts the supporting part of the amplification frame.

[0016] The piezoelectric driver includes an input protection circuit module, a low-voltage amplifier circuit module, a high-voltage amplifier circuit module, an output protection circuit module, and a capacitive load matching circuit module connected in series. The low-voltage amplifier circuit module is connected to a low-voltage power supply, and the high-voltage amplifier circuit module is connected to a high-voltage power supply on one side and to a phase compensation circuit module on the other side.

[0017] The clamping unit has a connecting hole at the end of the clamping arm that is fixed to the upper end of the vertical arm of the corresponding side amplification lever arm. The clamping unit includes two types of clamping arms that can be used interchangeably, one of which is a high-rigidity clamping arm and the other is a low-rigidity strain-sensing clamping arm.

[0018] The high-rigidity clamping arm includes a clamping arm segment and a connecting arm segment connected in sequence, wherein the clamping arm segment is inclined and the free end of the connecting arm segment is provided with a connecting hole.

[0019] The low-stiffness strain sensing clamping arm includes a first arm segment, a second arm segment, a third arm segment, and a fourth arm segment connected in sequence. The first arm segment is inclined, the second arm segment and the fourth arm segment are parallel, and the two ends of the third arm segment are respectively connected to the lower ends of the second arm segment and the lower ends of the fourth arm segment. The second arm segment, the third arm segment, and the fourth arm segment form a strain sensor mounting groove, and the upper end of the fourth arm segment is provided with a connecting hole.

[0020] The advantages and positive effects of this invention are as follows:

[0021] 1. The present invention adopts a two-stage displacement amplification structure formed by an amplification frame and an amplification lever arm, which can effectively realize the micron-level displacement of the piezoelectric ceramic unit to the large displacement output at the end of the clamping arm, with a total amplification factor of more than 12 times, and the structure is compact, efficient and reliable.

[0022] 2. This invention replaces the traditional single large-capacitor piezoelectric ceramic unit with two independent piezoelectric ceramic units, which can significantly reduce the capacitive load of a single driver and effectively improve the bandwidth and dynamic response performance of the drive circuit, making it particularly suitable for high-dynamic micro-nano manipulation scenarios.

[0023] 3. The clamping unit of this invention is designed with a quick-change clamping arm structure, and different types of clamping arms with different stiffness and functions can be flexibly selected according to different application requirements. The clamping force range covers from millineutons to 10 Newtons, which can meet the clamping requirements of different scenarios and improve the application range and flexibility of the micro gripper.

[0024] 4. In the low stiffness strain sensing clamping arm of the present invention, the second arm segment, the third arm segment, and the fourth arm segment form a strain sensor mounting groove to install the strain sensor and realize the real-time detection and feedback of the clamping force. Its measurement accuracy can reach 1mN, which is particularly suitable for high-precision real-time control requirements. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention.

[0026] Figure 2 for Figure 1 A schematic diagram of the structure of the medium-sized base.

[0027] Figure 3 for Figure 1 A schematic diagram of the high-rigidity clamping arm structure used in the embodiment is shown.

[0028] Figure 4 This is a schematic diagram of a low-stiffness strain-sensing clamping arm structure used in another embodiment of the present invention.

[0029] Figure 5 for Figure 1 Schematic diagram of the structure of a medium-voltage ceramic unit.

[0030] Figure 6 for Figure 5 A schematic diagram showing the alternating stacking of piezoelectric ceramic sheets and electrode layers inside the medium-voltage housing.

[0031] Figure 7 This is a schematic diagram of the working state of the magnification frame in the magnification base of the present invention.

[0032] Figure 8 This is a schematic diagram showing the working state of the magnifying lever arm in the magnifying base of the present invention.

[0033] Figure 9 This is a schematic diagram showing the overall working state of the magnified base of the present invention.

[0034] Figure 10 This is a schematic diagram of the structure of a piezoelectric actuator that works in conjunction with the piezoelectric ceramic unit of the present invention.

[0035] Figure 11 for Figure 10 Frequency response curve of a medium-voltage electric actuator driving a 0.7μF piezoelectric ceramic.

[0036] Figure 12 for Figure 10 Frequency response curve of a medium-voltage electric actuator driving a 1.4μF piezoelectric ceramic.

[0037] Wherein, 1 is the clamping unit, 101 is the connecting arm segment, 102 is the clamping arm segment, 103 is the connecting hole, 104 is the first arm segment, 105 is the second arm segment, 106 is the strain sensor mounting slot, 107 is the third arm segment, 108 is the fourth arm segment, 2 is the piezoelectric ceramic unit, 201 is the piezoelectric housing, 202 is the insulating top cover, 203 is the insulating bottom cover, 204 is the positive electrode lead, 205 is the negative electrode lead, 206 is the piezoelectric ceramic sheet, 207 is the electrode layer, 3 is the amplification base, 301 is the amplification lever arm, 3011 is the connecting block, 3012 is the lever hinge part, 3013 is the hinge shaft, 3014 is... The components are as follows: 3015 is the force-applying end; 302 is the piezoelectric frame; 3021 is the limiting part; 3022 is the connecting part; 3023 is the threaded hole; 303 is the amplifying frame; 3031 is the connecting hinge part; 3032 is the fixed base; 3033 is the support part; 3034 is the base fixing hole; 4 is the fixing screw; 5 is the piezoelectric actuator; 501 is the input protection circuit module; 502 is the low-voltage amplification circuit module; 503 is the high-voltage amplification circuit module; 504 is the output protection circuit module; 505 is the capacitive load matching circuit module; 506 is the low-voltage power supply; 507 is the high-voltage power supply; and 508 is the phase compensation circuit module. Detailed Implementation

[0038] The invention will now be described in further detail with reference to the accompanying drawings.

[0039] like Figures 1-12 As shown, the present invention includes a clamping unit 1, a piezoelectric ceramic unit 2, and an amplifying base 3. The amplifying base 3 includes a piezoelectric frame 302, an amplifying frame 303, and an amplifying lever arm 301. The amplifying frame 303 includes a fixed base 3032, a connecting hinge portion 3031, and a support portion 3033. Two amplifying lever arms 301 are respectively disposed on both sides of the amplifying frame 303, and each amplifying lever arm 301 includes a horizontal arm and a vertical arm arranged in an L-shape. The force-bearing end 3014 on the inner side of the horizontal arm is connected to the corresponding end of the support portion 3033 through the corresponding connecting hinge portion 3031 on one side, and the other side is connected to the corresponding end of the support portion 3033 through the corresponding connecting hinge portion 303 on the other side. 1. Connected to the corresponding end of the fixed base 3032, the clamping unit 1 includes clamping arms on both sides, and the lower end of the clamping arm is connected to the upper end of the vertical arm on the corresponding side. The piezoelectric frame 302 is concave, including connecting parts 3022 on both sides and a limiting part 3021 in the middle. Two piezoelectric ceramic units 2 are arranged side by side in the piezoelectric frame 302 and are located between the limiting part 3021 and the support part 3033 of the amplifying frame 303. The vertical arm is provided with a lever hinge part 3012, and the lower ends of the connecting parts 3022 on both sides of the piezoelectric frame 302 are respectively hinged to the free ends of the lever hinge parts 3012 on the corresponding side through hinge shafts 3013. When the present invention is working, as follows... Figures 7-9As shown, when the piezoelectric ceramic unit 2 generates a driving displacement of Δx in the Z direction, a first-level amplification can be formed through the amplification frame 303. At this time, the force-receiving end 3014 on the inner side of the horizontal arm of the amplification lever arm 301 is displaced by Δx1 in the X direction, and the force-applying end 3015 on the outer side of the horizontal arm connected to the vertical arm is also displaced by Δx1 in the X direction. The force-applying end 3015 on the outer side of the horizontal arm drives the vertical arm and the clamping arm of the clamping unit 1 to rotate around the center of the hinge axis 3013, and causes the end of the clamping arm to be displaced by Δy in the X direction, thereby forming a second-level amplification. Through simulation and experimental calculations, for the micron-level initial displacement (Δx) at the output end of the piezoelectric ceramic unit 2, after the first-stage amplification by the amplification frame 303, the displacement (Δx1) can be amplified by 5 to 6 times. After the second-stage amplification by the amplification lever arm 301, the displacement (Δy) can be further amplified by 2 to 3 times. Finally, the displacement (Δy) at the end of the clamping arm can be amplified by more than 12 times. This can effectively meet the requirements of large displacement precision clamping in micro-nano manipulation scenarios. At the same time, the design structure of this invention is simple and compact, with high amplification efficiency and stable reliability, which greatly improves the ability of the clamp to meet the requirements of high precision, large displacement, and high dynamic response.

[0040] In this embodiment, both the connecting hinge portion 3031 of the magnifying frame 303 and the lever hinge portion 3012 of the magnifying lever arm 301 adopt a flexible circular hinge structure. This is a well-known technology in the art, and can be found in patents such as CN205521129U. Figures 1-2 and Figure 7 As shown, the force-bearing end 3014 on the inner side of the horizontal arm forms a triangular structure with the connecting hinge portions 3031 on both sides. The small displacement Δx generated by the piezoelectric ceramic unit 2 along the Z direction is applied to the support portion 3033, thereby causing each connecting hinge portion 3031 to produce its own elastic deformation. The circular notch on the connecting hinge portion 3031 is the elastic deformation part, that is, the hinge. After the connecting hinge portion 3031 is subjected to force, each hinge (circular notch) will produce a small angle. The superposition of the small angles can cause the inner side of the horizontal arm to deform. The force-bearing end 3014 on the side generates a significantly amplified displacement output Δx1. This amplification effect is directly related to the geometric dimensions of the triangular structure formed by the force-bearing end 3014 and the connecting hinge parts 3031 on both sides, as well as the stiffness of the connecting hinge parts 3031. Furthermore, by rationally designing the distance between the support part 3033 and the fixed base 3032, the size of the arc radius at each hinge of the connecting hinge part 3031, and the side length and included angle of the triangular structure formed by the force-bearing end 3014 and the connecting hinge parts 3031 on both sides, the present invention can achieve precise control of displacement amplification.

[0041] And such Figure 8As shown, the amplifying lever arm 301 uses the lever hinge part 3012 as a hinge fulcrum to support and rotate, thereby realizing the transmission and conversion of force and displacement. The horizontal arm force-applying end 3015 of the amplifying lever arm 301 applies a pushing force to the vertical arm, and the small-amplitude movement generated by the horizontal arm force-applying end 3015 can achieve a larger displacement output (Δy) at the end of the clamping arm of the clamping unit through the mechanical amplification effect of the lever arm length.

[0042] like Figures 1-2 As shown, in this embodiment, the upper end of the vertical arm of the magnifying lever arm 301 is provided with a connecting block 3011, and the connecting block 3011 is fixedly connected to the lower end of the corresponding side clamping arm by a fixing screw 4.

[0043] like Figures 1-2 As shown, in this embodiment, the fixed base 3032 of the magnifying frame 303 is provided with a base fixing hole 3034 for fixing to the relevant structure.

[0044] like Figures 1-2 As shown, in this embodiment, the limiting part 3021 of the piezoelectric frame 302 is provided with a threaded hole 3023 for fixing the piezoelectric ceramic unit 2.

[0045] In this embodiment, the amplification frame 303 and the amplification lever arm 301 are made of aluminum alloy 7075-T6 or titanium alloy Ti-6Al-4V, which have high elastic deformation accuracy and long fatigue life. In addition, since the displacement amplification factor of the present invention is large, the overall structure is more compact. In this embodiment, the overall external dimensions of the amplification base 3 are 45mm×45mm, which can realize efficient displacement amplification and high bandwidth piezoelectric drive in a compact space.

[0046] like Figures 5-6 As shown, in this embodiment, the piezoelectric ceramic unit 2 includes a piezoelectric housing 201, and piezoelectric ceramic sheets 206 and electrode layers 207 are staggered along the length direction inside the piezoelectric housing 201. The piezoelectric ceramic sheets 206 and electrode layers 207 are stacked and sintered in an alternating manner, and can achieve micron-level longitudinal expansion and contraction displacement by applying an external high-voltage signal. The upper end of the piezoelectric housing 201 is provided with a positive electrode lead 204 and a negative electrode lead 205, which are connected to the piezoelectric actuator 5 for applying a high-voltage signal to the piezoelectric ceramic sheets 206 and electrode layers 207. In addition, the upper end of the piezoelectric housing 201 is provided with an insulating top cover 202 that contacts the limiting part 3021 of the piezoelectric frame 302, and the lower end is provided with an insulating bottom cover 203 that contacts the supporting part 3033 of the amplification frame 303. The materials of the piezoelectric ceramic sheets 206 and electrode layers 207 are both known in the art.

[0047] like Figure 10As shown, in this embodiment, the positive electrode lead 204 and the negative electrode lead 205 are connected to the piezoelectric actuator 5. The piezoelectric actuator 5 includes an input protection circuit module 501, a low-voltage amplifier circuit module 502, a high-voltage amplifier circuit module 503, an output protection circuit module 504, and a capacitive load matching circuit module 505 connected in series. The low-voltage amplifier circuit module 502 is connected to the low-voltage power supply 506, and one side of the high-voltage amplifier circuit module 503 is connected to the high-voltage power supply 507, and the other side is connected to the phase compensation circuit module 508. The working principle of the piezoelectric driver 5 is as follows: First, the low-voltage control signal (±10V) input from the outside passes through the input protection circuit module 501 and then enters the low-voltage amplifier circuit module 502, which linearly converts the ±10V bipolar control signal into a unipolar 0 to -10V signal suitable for subsequent high-voltage amplification. Then, the 0 to -10V signal passes through the high-voltage amplifier circuit module 503, which uses the high-voltage DC bias provided by the high-voltage power supply 507 to achieve a significant voltage amplification, amplifying the 0 to -10V low-voltage signal to the 0 to 150V high-voltage signal required to drive the piezoelectric ceramic unit 2, forming a drive output signal, and finally transmitting it to the piezoelectric ceramic unit 2. During the high-voltage amplification process, since the piezoelectric ceramic is essentially a capacitive load, the larger the load capacitance, the faster the capacitive reactance decreases when the frequency of the amplifier output signal increases, and the current flowing into the load increases significantly, which leads to increased heating of the amplifier circuit and serious phase lag, thereby limiting the bandwidth of the driver. To address the aforementioned issues, this invention employs a phase compensation circuit module 508 and a capacitive load matching circuit module 505 to effectively improve the amplifier's phase characteristics, enhance overall bandwidth and stability, and ensure that the driver can efficiently and stably achieve high-bandwidth driving of the piezoelectric ceramic.

[0048] In one application example of the present invention, the piezoelectric actuator 5 described above is used to drive two individual piezoelectric ceramic units 2, each with a capacitance of 0.7 μF. The frequency response curve (Bohr plot) of each individual 0.7 μF piezoelectric ceramic unit 2 is as follows: Figure 10 As shown in the figure, the vertical axis represents the gain ratio (in dB) and phase (degrees) of the amplifier's output signal to its input signal, and the horizontal axis represents the frequency (Hz). Figure 10As can be seen, within the 1kHz to 10kHz frequency band, the gain of this application example stabilizes at around 20dB, indicating that the piezoelectric driver 5 has good driving stability and gain flatness for capacitive loads, and can reliably achieve high-voltage precision driving. Above 10kHz, the amplifier gain curve gradually decreases, showing significant attenuation near 100kHz, indicating that the system bandwidth can reach tens of kHz, fully meeting the performance requirements of the micro / nano gripper under high-frequency dynamic operating conditions. Compared with traditional single-channel piezoelectric drive schemes with large capacitors (e.g., 1.4μF and above), the scheme in this invention, which uses two low-capacitance (0.7μF per chip) piezoelectric ceramic units 2 and drives them independently, effectively halves the capacitive load of the single-channel drive amplifier, significantly reducing the difficulty of drive circuit design. This allows the amplifier to achieve higher bandwidth and better dynamic performance, making it particularly suitable for high-speed, precise gripping operations at the micro / nano scale, and significantly improving the gripper's adaptability to different application scenarios.

[0049] And such Figure 11 The diagram shows a comparative example of the above application, specifically the frequency response curve (Bode plot) of the piezoelectric driver 5 driving only one 1.4μF piezoelectric ceramic. The horizontal axis represents the input signal frequency, and the vertical axis represents the driver output gain (in dB) and phase (in °), respectively. As can be seen from the frequency response curve, when the capacitive load of the piezoelectric ceramic increases to 1.4μF, the gain and phase performance of this comparative example significantly decrease. Specifically, the amplifier can maintain a stable gain of around 20dB up to 1kHz; however, when the frequency exceeds 1kHz, the amplifier gain drops rapidly; at 10kHz, the gain has dropped to around 13dB, and at higher frequencies (above approximately 30kHz), the gain even drops below 10dB, indicating a severe bandwidth limitation. This contrasts sharply with the case of using two 0.7μF piezoelectric ceramics for independent driving (see...). Figure 10 The high capacitive load of a single 1.4μF piezoelectric ceramic results in a higher output current demand for the driver, leading to increased heat loss and reduced frequency response in the drive circuit, thus limiting high-frequency dynamic response capabilities. This invention, by comparing the frequency response characteristics of a single large-capacitance ceramic with two independent small-capacitance ceramics, clearly verifies that using a dual-path independent drive method can significantly improve the frequency bandwidth of the amplifier and the dynamic response performance of the system. This is particularly suitable for micro-nano manipulation applications with higher requirements for clamping speed, bandwidth, and stability. Therefore, this invention uses two independent small-capacitance (0.7μF) piezoelectric ceramic units to drive the system separately, replacing the conventional single large-capacitance (1.4μF) piezoelectric ceramic unit, which produces unexpected technical effects.

[0050] like Figures 3-4As shown, the clamping arm end of the clamping unit 1 of the present invention is provided with a connecting hole 103 for fixed connection with the upper end of the vertical arm of the corresponding side amplification lever arm 301. The clamping unit 1 of the present invention includes two interchangeable clamping arms, one of which is a high-rigidity clamping arm and the other is a low-rigidity strain-sensing clamping arm.

[0051] like Figure 3 As shown, in this embodiment, the high-rigidity clamping arm includes a clamping arm segment 102 and a connecting arm segment 101 connected in sequence. The clamping arm segment 102 is inclined, and the free end of the connecting arm segment 101 is provided with a connecting hole 103. The high-rigidity clamping arm can achieve a large clamping force of more than 10N.

[0052] like Figure 4 As shown, the low-stiffness strain-sensing clamping arm includes a first arm segment 104, a second arm segment 105, a third arm segment 107, and a fourth arm segment 108 connected in sequence. The first arm segment 104 is inclined for clamping, the second arm segment 105 and the fourth arm segment 108 are parallel, and the two ends of the third arm segment 107 are perpendicularly connected to the lower ends of the second arm segment 105 and the fourth arm segment 108, respectively. The second arm segment 105, the third arm segment 107, and the fourth arm segment 108 form a strain sensor mounting groove 106 to install a strain sensor for real-time detection and feedback of the clamping force. The clamping force measurement accuracy can reach 1mN. The upper end of the fourth arm segment 108 is provided with a connecting hole 103. The thickness of each arm segment of the low-stiffness strain-sensing clamping arm is reduced and the cantilever length is increased. According to Hooke's law, it will generate a relatively small clamping force on the object.

[0053] The working principle of this invention is as follows:

[0054] When this invention is working, as Figures 7-9 As shown, when the piezoelectric ceramic unit 2 generates a driving displacement of Δx in the Z direction, a first-stage amplification can be formed through the amplification frame 303. At this time, the force-receiving end 3014 on the inner side of the horizontal arm of the amplification lever arm 301 displaces Δx1 in the X direction, and the force-applying end 3015 on the outer side of the horizontal arm connected to the vertical arm also displaces Δx1 in the X direction. The force-applying end 3015 on the outer side of the horizontal arm drives the vertical arm and the clamping arm of the clamping unit 1 to rotate around the center of the hinge axis 3013, and causes the end of the clamping arm to displace Δy in the X direction, thereby forming a second-stage amplification. Through simulation and experimental calculation, the present invention can ultimately achieve an amplification factor of more than 12 times for the displacement (Δy) of the end of the clamping arm, which can effectively meet the requirements of large displacement precision clamping in micro-nano manipulation scenarios. At the same time, the present invention has a simple and compact design structure, high amplification efficiency, and stable and reliable performance, which greatly improves the ability of the clamp to meet the requirements of high precision, large displacement, and high dynamic response.

[0055] like Figures 1-2 and Figures 10-11As shown, this invention uses two independent small-capacitance (0.7μF) piezoelectric ceramic units to drive the piezoelectric ceramics separately, instead of driving it with a single conventional large-capacitance (1.4μF) piezoelectric ceramic unit. This significantly improves the frequency bandwidth and dynamic response performance of the system, making it particularly suitable for micro-nano manipulation applications where clamping speed, bandwidth, and stability are more critical. Furthermore, the piezoelectric driver 5 of this invention employs a phase compensation circuit module 508 and a capacitive load matching circuit module 505 to effectively improve the amplifier's phase characteristics, enhance overall bandwidth and stability, and ensure that the driver can efficiently and stably achieve high-bandwidth driving of the piezoelectric ceramics.

[0056] like Figures 1-4 As shown, the clamping arm end of the clamping unit 1 of the present invention is provided with a connecting hole 103 for the fixing screw 4 to pass through, thereby realizing the connection with the connecting block 3011 at the upper end of the vertical arm of the corresponding side amplifying lever arm 301. The clamping unit 1 of the present invention includes two types of clamping arms that can be used interchangeably, one of which is a high-rigidity clamping arm and the other is a low-rigidity strain sensing clamping arm. The present invention can flexibly select the appropriate clamping arm according to the situation of the clamped object, thereby meeting the needs of different clamping scenarios. Furthermore, the amplifying frame 303 and the amplifying lever arm 301 of the present invention can ultimately form an amplification factor of more than 12 times the displacement (Δy) at the end of the clamping arm, without affecting the conversion and use of the above clamping arm structure.

Claims

1. A high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive, characterized in that: The system includes a clamping unit (1), a piezoelectric ceramic unit (2), and an amplification base (3). The amplification base (3) includes a piezoelectric frame (302), an amplification frame (303), and an amplification lever arm (301). The amplification frame (303) includes a fixed base (3032), a connecting hinge (3031), and a support (3033). Two amplification lever arms (301) are respectively disposed on both sides of the amplification frame (303), and the amplification lever arm (301) includes a horizontal arm and a vertical arm arranged in an L-shape. The force-bearing end (3014) on the inner side of the horizontal arm is connected to the corresponding end of the support (3033) through the corresponding connecting hinge (3031) on one side, and the other side is connected through the corresponding connecting hinge (3031) on the other side. The hinge part (3031) is connected to the corresponding end of the fixed base (3032). The clamping unit (1) includes clamping arms on both sides, and the lower end of the clamping arm is connected to the upper end of the vertical arm on the corresponding side. The piezoelectric frame (302) is concave and includes connecting parts (3022) on both sides and a limiting part (3021) in the middle. Two piezoelectric ceramic units (2) are arranged side by side in the piezoelectric frame (302) and are located between the limiting part (3021) and the support part (3033) of the magnifying frame (303). The vertical arm is provided with a lever hinge part (3012), and the lower ends of the connecting parts (3022) on both sides of the piezoelectric frame (302) are respectively hinged to the lever hinge part (3012) on the corresponding side.

2. The high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive according to claim 1, characterized in that: The force-bearing end (3014) on the inner side of the horizontal arm and the connecting hinge parts (3031) on both sides form a triangular structure. The connecting hinge parts (3031) are provided with multiple circular notches, and the circular notches form hinge parts that generate elastic deformation.

3. The high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive according to claim 1, characterized in that: The upper end of the vertical arm of the amplifying lever arm (301) is provided with a connecting block (3011), and the connecting block (3011) is fixedly connected to the lower end of the corresponding side clamping arm by a fixing screw (4).

4. The high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive according to claim 1, characterized in that: The fixed base (3032) of the magnified frame (303) is provided with a base fixing hole (3034).

5. The high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive according to claim 1, characterized in that: The limiting part (3021) of the piezoelectric frame (302) is provided with a threaded hole (3023) for fixing the piezoelectric ceramic unit (2).

6. The high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive according to claim 1, characterized in that: The piezoelectric ceramic unit (2) includes a piezoelectric housing (201), and piezoelectric ceramic sheets (206) and electrode layers (207) are arranged alternately along the length direction inside the piezoelectric housing (201). The upper end of the piezoelectric housing (201) is provided with a positive electrode lead (204) and a negative electrode lead (205) connected to the piezoelectric actuator (5). In addition, the upper end of the piezoelectric housing (201) is provided with an insulating top cover (202) that contacts the limiting part (3021) of the piezoelectric frame (302), and the lower end is provided with an insulating bottom cover (203) that contacts the supporting part (3033) of the amplification frame (303).

7. The high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive according to claim 6, characterized in that: The piezoelectric driver (5) includes an input protection circuit module (501), a low-voltage amplifier circuit module (502), a high-voltage amplifier circuit module (503), an output protection circuit module (504), and a capacitive load matching circuit module (505) connected in series. The low-voltage amplifier circuit module (502) is connected to a low-voltage power supply (506), and the high-voltage amplifier circuit module (503) is connected to a high-voltage power supply (507) on one side and to a phase compensation circuit module (508) on the other side.

8. The high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive according to claim 1, characterized in that: The clamping unit (1) has a connecting hole (103) at the end of the clamping arm that is fixed to the upper end of the vertical arm of the corresponding side amplification lever arm (301). The clamping unit (1) includes two types of clamping arms that can be used interchangeably, one of which is a high-rigidity clamping arm and the other is a low-rigidity strain sensing clamping arm.

9. The high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive according to claim 8, characterized in that: The high-rigidity clamping arm includes a clamping arm segment (102) and a connecting arm segment (101) connected in sequence, wherein the clamping arm segment (102) is inclined and the free end of the connecting arm segment (101) is provided with a connecting hole (103).

10. The high-amplitude variable clamping force micro / nano clamping device with dual piezoelectric drive according to claim 8, characterized in that: The low-stiffness strain sensing clamping arm includes a first arm segment (104), a second arm segment (105), a third arm segment (107), and a fourth arm segment (108) connected in sequence. The first arm segment (104) is inclined, the second arm segment (105) and the fourth arm segment (108) are parallel, and the two ends of the third arm segment (107) are respectively connected to the lower ends of the second arm segment (105) and the lower ends of the fourth arm segment (108). The second arm segment (105), the third arm segment (107), and the fourth arm segment (108) form a strain sensor mounting groove (106). The upper end of the fourth arm segment (108) is provided with a connecting hole (103).

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