Piezoelectric macro- and micro force sensing devices and measurement methods

Abstract

This invention relates to a piezoelectric macro-micro force sensing device and measurement method, which solves the problem that existing force sensors cannot meet the requirements for quasi-static measurement of minute forces, belonging to the field of macro-micro force measurement technology. The invention utilizes two force-measuring units with piezoelectric ceramics as sensing elements and a piezoelectric quartz reference unit with a piezoelectric quartz crystal as the sensing element as sensors. The piezoelectric quartz reference unit measures macroscopic forces, while the force-measuring units measure minute forces. Continuous quasi-static measurement of minute forces can be achieved by alternating between the two force-measuring units. The high sensitivity of piezoelectric ceramics improves sensor resolution; the good linearity, high temperature stability, and no hysteresis of piezoelectric quartz improve sensor stability. This invention balances the high accuracy and large range of force sensors, enabling the measurement of multi-range quasi-static macro-micro forces, and also possesses advantages such as high stiffness and high frequency response.

Description

Technical Field

[0001] This invention relates to a piezoelectric macro-micro force sensing device and measurement method, belonging to the field of macro-micro force measurement technology. Background Technology

[0002] In modern industry and scientific research, force sensors are increasingly widely used in fields such as industrial automation, medicine, and aerospace. As research deepens, the demand for the measurement and monitoring of minute forces is increasing in fields such as precision measurement, precision machining, materials research, and biomechanics.

[0003] Current force sensors often fail to simultaneously achieve both high accuracy and large measurement range, and suffer from limitations when measuring minute forces, such as low sensitivity, bulky size, and long response time. The invention patent CN103575436A, "Multi-range Macro-Micro Force Sensor," achieves multi-range macro-micro force measurement by attaching strain gauges to elastic sheets of varying rigidity. However, this type of macro-micro force sensor has weak stiffness, is easily damaged under large forces, and suffers from drawbacks such as weak stiffness and low frequency response during force measurement. Therefore, a novel macro-micro force sensing device is needed to address these issues.

[0004] Piezoelectric technology is a commonly used method of force sensing. Its basic principle is to utilize the properties of piezoelectric materials to generate electric charge or voltage signals under the action of force. Piezoelectric materials have advantages such as high sensitivity, fast response, and a wide operating frequency range, and are therefore widely used in the field of force sensors.

[0005] However, existing commercial piezoelectric sensors primarily use piezoelectric quartz as the sensing element, which presents challenges when simultaneously measuring macroscopic and microscopic forces. Under macroscopic forces, piezoelectric quartz can provide high-precision and high-sensitivity measurements with no hysteresis and high temperature stability. However, when measuring microscopic forces, the sensor's sensitivity and resolution are limited, failing to meet the requirements for accurate measurement.

[0006] In contrast, piezoelectric ceramics have a higher piezoelectric coefficient and advantages such as small size and high sensitivity. They can generate distinguishable charges under the action of small forces, making them suitable for measuring small forces and improving the accuracy of force sensors. However, the insulation impedance of piezoelectric ceramics is much lower than that of piezoelectric quartz, resulting in serious charge leakage problems. They also suffer from hysteresis and poor temperature stability, making them unsuitable for detecting small quasi-static forces and failing to meet the requirements for quasi-static measurement of small forces. Summary of the Invention

[0007] To address the problem that existing force sensors are insufficient for quasi-static measurement of minute forces, this invention provides a piezoelectric macro-micro force sensing device and measurement method.

[0008] This invention relates to a piezoelectric macro-micro force sensing device and measurement method.

[0009] It includes force measuring unit I, force measuring unit II, piezoelectric quartz reference unit, charge amplifier I, charge amplifier II and charge amplifier III, data acquisition card, microcontroller and processing module;

[0010] Both force measuring unit I and force measuring unit II use piezoelectric ceramic sheets as sensing elements;

[0011] The piezoelectric quartz reference cell uses a piezoelectric quartz crystal as the sensing element;

[0012] The processing module is used to output control signals to the microcontroller, which controls the measurement states of charge amplifier I, charge amplifier II, and charge amplifier III. The measurement states include reset, dynamic, and quasi-static.

[0013] The piezoelectric quartz reference unit continuously measures macroscopic quasi-static force or macroscopic dynamic force.

[0014] When measuring minute quasi-static force signals, force measuring unit I and force measuring unit II work alternately, and there is an overlap time between each alternation measurement;

[0015] The measurement results of force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are input to charge amplifier I, charge amplifier II, and charge amplifier III, respectively. The outputs of charge amplifier I, charge amplifier II, and charge amplifier III are simultaneously input to the data acquisition card. The output of the data acquisition card is input to the processing module. The processing module determines the macroscopic quasi-static force, macroscopic dynamic force, microscopic quasi-static force, or microscopic dynamic force based on the input.

[0016] As a preferred embodiment, the force measuring unit I includes electrode plate 2 (No. 1), piezoelectric ceramic plate 3 (No. 1), and electrode plate 4 (No. 2).

[0017] The positive electrode of piezoelectric ceramic sheet 3 is in contact with electrode sheet 2, and the negative electrode of piezoelectric ceramic sheet 3 is in contact with electrode sheet 4. Electrode sheet 2 and electrode sheet 4 are the positive and negative output terminals of force measuring unit I.

[0018] Force measuring unit II includes electrode plate 6 (No. 3), piezoelectric ceramic plate 7 (No. 2), and electrode plate 8 (No. 4);

[0019] The positive electrode of piezoelectric ceramic sheet 7 is in contact with electrode sheet 6, and the negative electrode of piezoelectric ceramic sheet 7 is in contact with electrode sheet 8, which are the positive and negative output terminals of force measuring unit II.

[0020] Preferably, the piezoelectric quartz reference unit includes an upper electrode plate 10, an X0 piezoelectric quartz upper wafer 11, a middle electrode plate 12, an X0 piezoelectric quartz lower wafer 13, and a lower electrode plate 14.

[0021] The upper X0 piezoelectric quartz wafer 11 and the lower X0 piezoelectric quartz wafer 13 are arranged opposite each other with their negative electrodes facing each other and arranged 180 degrees apart along the Y-axis.

[0022] The upper electrode 10 and the lower electrode 14 are connected by a wire to serve as the positive output terminal of the piezoelectric quartz reference unit, and the middle electrode 12 serves as the negative output terminal of the piezoelectric quartz reference unit.

[0023] Preferably, the force measuring unit I and the force measuring unit II, and the force measuring unit II and the piezoelectric quartz reference unit are insulated with polytetrafluoroethylene sheets.

[0024] Preferably, the device further includes a sensor cover 1, a sensor base 17, an outer insulating sleeve 15, and an inner insulating sleeve 16;

[0025] Force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are placed inside sensor base 17. Sensor cover 1 is fixed above sensor base 17. Force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are insulated from sensor base 17 through inner insulating sleeve 16 and outer insulating sleeve 15.

[0026] The present invention also provides a measurement method for a piezoelectric macro-micro force sensing device. When measuring a small quasi-static force, the measurement method includes:

[0027] S1, charge amplifier I, charge amplifier II, and charge amplifier III are all in quasi-static mode. The force measuring unit I and the force measuring unit II perform alternating measurements. The duration of a single measurement by charge amplifier I and charge amplifier II is T, and the overlap time of each alternating measurement is Δt. Charge amplifier III performs uninterrupted measurements.

[0028] S2. Reset charge amplifier I, charge amplifier II and charge amplifier III, set the sensitivity coefficient and gain factor of each charge amplifier, and normalize the force signals output by charge amplifier I, charge amplifier II and charge amplifier III to obtain the force signals of all channels;

[0029] S3, the start time of a single measurement by charge amplifier I is denoted as T. 11 The end time is denoted as T. 12 Calculate (T) 11 The average value of each sampling point of charge amplifier I and charge amplifier III within the time period +Δt) Calculate (T) 12 The average value of each sampling point of charge amplifier I and charge amplifier III within the time period -Δt)

[0030] S4. Calculate the slope difference between charge amplifier I and charge amplifier III.

[0031] S5, in T 11 ~T 12 During a given time period, the force signal F1 output by charge amplifier I is processed: The shaped data... t represents time;

[0032] S6. The start time of a single measurement by charge amplifier II is denoted as T. 21 The end time is denoted as T. 22 Calculate (T) 21 The average value of each sampling point of charge amplifier II and charge amplifier III within the time period +Δt) Calculate (T) 22 The average value of each sampling point of charge amplifier II and charge amplifier III within the time period -Δt)

[0033] S7. Calculate the slope difference between charge amplifier II and charge amplifier III.

[0034] S8, in T 21 ~T 22 During a given time period, the force signal F2 output by charge amplifier II is processed: shaped data...

[0035] S9. Taking Δt / 2 as the boundary, in (T) 11 +Δt / 2)~(T 12 -Δt / 2) time period As a perceived minute quasi-static force, in (T 21 +Δt / 2)~(T 22 -Δt / 2) time period The perceived minute quasi-static force;

[0036] S10, repeat S3 to S9 to achieve alternating measurements.

[0037] Preferably, when measuring minute dynamic forces, both charge amplifier I and charge amplifier II are in dynamic mode, force measuring unit I and force measuring unit II work simultaneously, and the weighted sum of the dynamic force signals of force measuring unit I and force measuring unit II is the sensed minute dynamic force.

[0038] Preferably, when measuring macroscopic quasi-static forces, charge amplifier III operates in quasi-static mode, and the piezoelectric quartz reference unit operates independently.

[0039] Preferably, when measuring macroscopic dynamic forces, charge amplifier III operates in dynamic mode, and the piezoelectric quartz reference unit works independently.

[0040] As a preferred method, when measuring the preload, the macroscopic force is determined based on the force signal output by the piezoelectric quartz reference unit; after the preload is applied, the quasi-static force is measured from micro to macroscopic as needed.

[0041] The beneficial effects of this invention are that, by combining piezoelectric ceramics and piezoelectric quartz, it enables both macroscopic measurements over a large force range and high-sensitivity measurements over a small force range, meeting the needs of a wide range of applications. The piezoelectric quartz crystal assembly provides excellent temperature stability and linearity, while the high sensitivity of the piezoelectric ceramics significantly improves the resolution of small force measurements. This invention achieves quasi-static measurement of small forces through the alternating operation of two piezoelectric ceramics, overcoming the charge leakage and hysteresis problems inherent in traditional piezoelectric ceramics in quasi-static measurements. Compared to traditional flexible structure sensors, this invention employs a rigid structure design, which not only enhances the overall stiffness of the sensor but also improves its dynamic response capability, making it suitable for high-frequency force measurement requirements. Attached Figure Description

[0042] Figure 1 This is a structural diagram of the piezoelectric macro-micro force sensing device described in this invention;

[0043] Figure 2 This is a diagram showing the composition of a piezoelectric macro-micro force sensing device measurement system.

[0044] Figure 3 Flowchart for the first alternating measurement of a small force signal in a quasi-static manner;

[0045] Figure 4 This is a schematic diagram illustrating the principle of a quasi-static measurement algorithm for minute force signals based on alternating measurements. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0048] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0049] The piezoelectric macro-micro force sensing device of this embodiment includes a force measuring unit I, a force measuring unit II, a piezoelectric quartz reference unit, a charge amplifier I, a charge amplifier II and a charge amplifier III, a data acquisition card, a microcontroller and a processing module;

[0050] Both force measuring unit I and force measuring unit II use piezoelectric ceramic sheets as sensing elements; piezoelectric ceramics have a high piezoelectric coefficient and can sensitively capture minute force signals;

[0051] The piezoelectric quartz reference cell uses a piezoelectric quartz crystal as the sensing element;

[0052] The piezoelectric quartz reference unit continuously measures macroscopic forces, playing a crucial role in providing a stable reference. Macroscopic forces include macroscopic quasi-static forces and macroscopic dynamic forces. When measuring macroscopic quasi-static forces or dynamic forces, the piezoelectric quartz reference unit operates independently.

[0053] When measuring minute quasi-static force signals, force measuring unit I and force measuring unit II work alternately, and there is an overlap time between each alternation measurement;

[0054] Force measuring unit I includes electrode plate 1 (2), piezoelectric ceramic plate 1 (3), and electrode plate 2 (4);

[0055] The positive electrode of piezoelectric ceramic sheet 3 is in contact with electrode sheet 2, and the negative electrode of piezoelectric ceramic sheet 3 is in contact with electrode sheet 4. Electrode sheet 2 and electrode sheet 4 are the positive and negative output terminals of force measuring unit I. After passing through lead connector 18, they are connected to the input terminal of charge amplifier I through coaxial shielding layer and wire core, respectively.

[0056] Force measuring unit II includes electrode plate 6 (3), piezoelectric ceramic plate 7 (2), and electrode plate 8 (4). The positive electrode of piezoelectric ceramic plate 7 (2) is in contact with electrode plate 6 (3), and the negative electrode of piezoelectric ceramic plate 7 (2) is in contact with electrode plate 8 (4). Electrode plates 6 (3) and 8 (4) are the positive and negative output terminals of force measuring unit II. After passing through lead connector 18, they are connected to the input terminal of charge amplifier II through coaxial shielding layer and wire core, respectively.

[0057] The piezoelectric quartz reference unit includes an upper electrode plate 10, an X0 piezoelectric quartz upper wafer 11, a middle electrode plate 12, an X0 piezoelectric quartz lower wafer 13, and a lower electrode plate 14;

[0058] The upper X0 piezoelectric quartz crystal 11 and the lower X0 piezoelectric quartz crystal 13 are arranged opposite each other at a 180-degree angle to each other along the Y-axis, forming a piezoelectric quartz crystal assembly.

[0059] The upper electrode 10 and the lower electrode 14 are connected by a wire to serve as the positive output terminal of the piezoelectric quartz reference unit, and the middle electrode 12 serves as the negative output terminal of the piezoelectric quartz reference unit. After passing through the lead connector 18, they are respectively connected to the input terminal of the charge amplifier III through the coaxial shielding layer and the wire core.

[0060] Force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are coaxially arranged to sense equal external forces.

[0061] like Figure 2 As shown, each force measuring unit converts its generated charge signal into a voltage signal through a charge amplifier, which is then acquired by a data acquisition card and transmitted to a computer for processing. The charge amplifier has three operating states: "reset / dynamic / quasi-static," which can be automatically switched by microcontroller logic control according to actual measurement needs, ensuring the continuity and accuracy of the measurement process.

[0062] The signals from the piezoelectric ceramic plates of force measuring unit I and force measuring unit II can be acquired independently for further analysis and processing. The measurement results of force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are respectively input to charge amplifier I, charge amplifier II, and charge amplifier III.

[0063] The processing module is used to output control signals to the microcontroller, which controls the measurement states of charge amplifier I, charge amplifier II, and charge amplifier III. The measurement states include reset, dynamic, and quasi-static.

[0064] The outputs of charge amplifier I, charge amplifier II, and charge amplifier III are simultaneously input to the data acquisition card, and the output of the data acquisition card is input to the processing module. The processing module determines the macroscopic force and the microscopic force based on the input.

[0065] Good insulation prevents signal interference between components. Force measuring unit I and force measuring unit II are insulated with PTFE sheet 5 (No. 1), and force measuring unit II and piezoelectric quartz reference unit are insulated with PTFE sheet 9 (No. 2). Internal components are also insulated with PTFE sheets to ensure electrical isolation between piezoelectric elements. Meanwhile, the sensor housing, made of rigid materials, ensures the overall rigidity and durability of the sensor, effectively preventing deformation and structural failure that may occur during measurement.

[0066] The sensor housing consists of a sensor cover 1, a sensor base 17, and a lead connector 18. Both the sensor cover 1 and the sensor base 17 are provided with bosses to ensure that the force is transmitted to the force measuring unit I, the force measuring unit II, and the piezoelectric quartz reference unit. After the sensor is assembled and a pre-tightening force is applied, the sensor cover 1 and the sensor base 17 are welded and encapsulated using an electron beam.

[0067] Force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are placed inside sensor base 17. Sensor cover 1 is fixed above sensor base 17. Force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are insulated from sensor base 17 through inner insulating sleeve 16 and outer insulating sleeve 15.

[0068] The piezoelectric macro-micro force sensing device of this embodiment can measure macroscopic forces, minute quasi-static forces, and minute dynamic forces. When performing high-precision measurements of minute quasi-static forces over a large range with small fluctuations, force measuring units I and II have smaller ranges, while the piezoelectric quartz reference unit has a larger range. During the initial measurement phase with a large static force, the output is the force signal from the piezoelectric quartz reference unit, yielding the macroscopic force. After the preload is applied, high-precision measurement of minute force fluctuations is initiated, and the output is a composite of the force signals from force measuring units I, II, and the piezoelectric quartz reference unit. This allows for the measurement of quasi-static forces ranging from minute to macroscopic as needed.

[0069] When measuring minute dynamic forces, both charge amplifier I and charge amplifier II are in dynamic mode. Force measuring unit I and force measuring unit II work simultaneously, and the output is a weighted average of the dynamic force signals from force measuring unit I and force measuring unit II, each accounting for 50%.

[0070] When measuring minute quasi-static forces, the measurement methods include:

[0071] Step 1: Charge amplifier I, charge amplifier II, and charge amplifier III are all in quasi-static mode. The computer controls the acquisition logic of all charge amplifiers through a microcontroller and acquires the voltage signals of force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit through a data acquisition card.

[0072] Force measuring unit I and force measuring unit II perform alternating measurements. The duration of a single measurement by charge amplifier I and charge amplifier II is T, and the overlap time of each alternating measurement is Δt. The computer records the start and end times of the alternating measurements, and charge amplifier III performs uninterrupted measurements.

[0073] Step 2: Reset charge amplifier I, charge amplifier II and charge amplifier III, set the sensitivity coefficient and gain factor of each charge amplifier, and normalize the force signals output by charge amplifier I, charge amplifier II and charge amplifier III by dividing by the gain factor of each charge amplifier to obtain the force signals of all channels.

[0074] Step 3: The start time of the first measurement by charge amplifier I is recorded as T. 11 The end time is denoted as T. 12 Calculate (T) 11 The average value of each sampling point of charge amplifier I and charge amplifier III within the time period +Δt) Calculate (T) 12 The average value of each sampling point of charge amplifier I and charge amplifier III within the time period -Δt)

[0075] Step 4: Calculate the slope difference between charge amplifier I and charge amplifier III.

[0076] Step 5, at T 11 ~T 12 During a given time period, the force signal F1 output by charge amplifier I is processed: The shaped data... t represents time;

[0077] Step 6: The start time of the first measurement by charge amplifier II is recorded as T. 21 The end time is denoted as T. 22 Calculate (T) 21 The average value of each sampling point of charge amplifier II and charge amplifier III within the time period +Δt) Calculate (T) 22 The average value of each sampling point of charge amplifier II and charge amplifier III within the time period -Δt)

[0078] Step 7: Calculate the slope difference between charge amplifier II and charge amplifier III.

[0079] Step 8, at T 21 ~T 22 During a given time period, the force signal F2 output by charge amplifier II is processed: shaped data...

[0080] Step 9: Using Δt / 2 as the boundary, in (T) 11 +Δt / 2)~(T 12 -Δt / 2) time period As a perceived minute quasi-static force, in (T 21 +Δt / 2)~(T 22 -Δt / 2) time period The perceived minute quasi-static force;

[0081] Step 10: Repeat steps 3 through 9 to perform alternating measurements.

[0082] When measuring macroscopic quasi-static forces, charge amplifier III operates in quasi-static mode, and the piezoelectric quartz reference unit works independently.

[0083] When measuring macroscopic dynamic forces, charge amplifier III operates in dynamic mode, and the piezoelectric quartz reference unit works independently.

[0084] In this embodiment, when performing high-precision quasi-static force measurement with a small range, the ranges of the high-resolution measurement module and the piezoelectric quartz reference unit are very small to ensure high sensitivity. Furthermore, when the signals of charge amplifier I and charge amplifier II exceed 80% of the current range, the reset function will be triggered in advance, and the measurement will continue by another charge amplifier, thereby enhancing the continuity of the measurement.

[0085] This embodiment uses two piezoelectric ceramics connected in series with a set of piezoelectric quartz crystals as a sensor. The piezoelectric quartz crystals measure macroforces, while the piezoelectric ceramics measure microforces. Continuous quasi-static measurement of microforces can be achieved by alternating between the two piezoelectric ceramics. The high sensitivity of the piezoelectric ceramics improves the sensor's resolution; the good linearity, high temperature stability, and hysteresis-free properties of the piezoelectric quartz enhance the sensor's stability. This invention balances high accuracy and a large range for force sensors, enabling the measurement of multi-range quasi-static macro and microforces, and also possesses advantages such as high stiffness and high frequency response.

[0086] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A piezoelectric macro-micro force sensing device, characterized in that, It includes force measuring unit I, force measuring unit II, piezoelectric quartz reference unit, charge amplifier I, charge amplifier II and charge amplifier III, data acquisition card, microcontroller and processing module; Both force measuring unit I and force measuring unit II use piezoelectric ceramic sheets as sensing elements; The piezoelectric quartz reference cell uses a piezoelectric quartz crystal as the sensing element; The processing module is used to output control signals to the microcontroller, which controls the measurement states of charge amplifier I, charge amplifier II, and charge amplifier III. The measurement states include reset, dynamic, and quasi-static. The piezoelectric quartz reference unit continuously measures macroscopic quasi-static force or macroscopic dynamic force. When measuring minute quasi-static force signals, force measuring unit I and force measuring unit II work alternately, and there is an overlap time between each alternation measurement; The measurement results of force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are input to charge amplifier I, charge amplifier II, and charge amplifier III, respectively. The outputs of charge amplifier I, charge amplifier II, and charge amplifier III are simultaneously input to the data acquisition card. The output of the data acquisition card is input to the processing module. The processing module determines the macroscopic quasi-static force, macroscopic dynamic force, microscopic quasi-static force, or microscopic dynamic force based on the input.

2. The piezoelectric macro-micro force sensing device according to claim 1, characterized in that, Force measuring unit I includes electrode plate No. 1, piezoelectric ceramic plate No. 1, and electrode plate No. 2; The positive electrode of piezoelectric ceramic sheet No. 1 is in contact with electrode sheet No. 1, and the negative electrode of piezoelectric ceramic sheet No. 1 is in contact with electrode sheet No.

2. Electrode sheets No. 1 and No. 2 are the positive and negative output terminals of force measuring unit I. Force measuring unit II includes electrode plate No. 3, piezoelectric ceramic plate No. 2, and electrode plate No. 4; The positive electrode of piezoelectric ceramic sheet No. 2 is in contact with electrode sheet No. 3, and the negative electrode of piezoelectric ceramic sheet No. 2 is in contact with electrode sheet No.

4. Electrode sheets No. 3 and No. 4 are the positive and negative output terminals of force measuring unit II.

3. The piezoelectric macro / micro force sensing device according to claim 1, characterized in that, The piezoelectric quartz reference unit includes an upper electrode plate, an X0 piezoelectric quartz upper wafer, a middle electrode plate, an X0 piezoelectric quartz lower wafer, and a lower electrode plate; The upper and lower X0 piezoelectric quartz wafers are arranged opposite each other, with their negative electrodes facing each other and 180 degrees apart along the Y-axis. The upper and lower electrode plates are connected by a wire to serve as the positive output terminal of the piezoelectric quartz reference unit, while the middle electrode plate serves as the negative output terminal of the piezoelectric quartz reference unit.

4. The piezoelectric macro / micro force sensing device according to claim 1, characterized in that, The force measuring unit I and the force measuring unit II, and the force measuring unit II and the piezoelectric quartz reference unit are insulated with polytetrafluoroethylene sheets.

5. The piezoelectric macro-micro force sensing device according to claim 4, characterized in that, The device also includes a sensor cover, a sensor base, an outer insulating sleeve, and an inner insulating sleeve; Force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are placed inside the sensor base, and the sensor cover is fixed above the sensor base. Force measuring unit I, force measuring unit II, and piezoelectric quartz reference unit are insulated from the sensor base through an inner insulating sleeve and an outer insulating sleeve.

6. A measurement method for a piezoelectric macro-micro force sensing device, characterized in that, When measuring minute quasi-static forces, the measurement methods include: S1, charge amplifier I, charge amplifier II, and charge amplifier III are all in quasi-static mode. The force measuring unit I and the force measuring unit II perform alternating measurements. The duration of a single measurement by charge amplifier I and charge amplifier II is T, and the overlap time of each alternating measurement is Δt. Charge amplifier III performs uninterrupted measurements. S2. Reset charge amplifier I, charge amplifier II and charge amplifier III, set the sensitivity coefficient and gain factor of each charge amplifier, and normalize the force signals output by charge amplifier I, charge amplifier II and charge amplifier III to obtain the force signals of all channels; S3, the start time of a single measurement by charge amplifier I is denoted as T. 11 The end time is denoted as T. 12 Calculate (T) 11 The average value of each sampling point of charge amplifier I and charge amplifier III within the time period +Δt) Calculate (T) 12 The average value of each sampling point of charge amplifier I and charge amplifier III within the time period -Δt) S4. Calculate the slope difference between charge amplifier I and charge amplifier III. S5, in T 11 ~T 12 During a given time period, the force signal F1 output by charge amplifier I is processed: The shaped data... t represents time; S6. The start time of a single measurement by charge amplifier II is denoted as T. 21 The end time is denoted as T. 22 Calculate (T) 21 The average value of each sampling point of charge amplifier II and charge amplifier III within the time period +Δt) Calculate (T) 22 The average value of each sampling point of charge amplifier II and charge amplifier III within the time period -Δt) S7. Calculate the slope difference between charge amplifier II and charge amplifier III. S8, in T 21 ~T 22 During a given time period, the force signal F2 output by charge amplifier II is processed: shaped data... S9. Taking Δt / 2 as the boundary, in (T) 11 +Δt / 2)~(T 12 -Δt / 2) time period As a perceived minute quasi-static force, in (T 21 +Δt / 2)~(T 22 -Δt / 2) time period The perceived minute quasi-static force; S10, repeat S3 to S9 to achieve alternating measurements.

7. The measurement method according to claim 6, characterized in that, When measuring minute dynamic forces, both charge amplifier I and charge amplifier II are in dynamic mode, and force measuring unit I and force measuring unit II work simultaneously. The weighted sum of the dynamic force signals from force measuring unit I and force measuring unit II is the sensed minute dynamic force.

8. The measurement method according to claim 6, characterized in that, When measuring macroscopic quasi-static forces, charge amplifier III operates in quasi-static mode, and the piezoelectric quartz reference unit works independently.

9. The measurement method according to claim 6, characterized in that, When measuring macroscopic dynamic forces, charge amplifier III operates in dynamic mode, and the piezoelectric quartz reference unit works independently.

10. The measurement method according to claim 6, characterized in that, When measuring the preload, the macroscopic force is determined based on the force signal output by the piezoelectric quartz reference unit; after the preload is applied, the quasi-static force is measured from micro to macroscopic as required.

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