Piezoelectric macro-micro force sensing device and measuring method

Abstract

The invention discloses a piezoelectric type macro-micro force sensing device and a measurement method, solves the problem that an existing force sensor is difficult to meet quasi-static measurement of micro force, and belongs to the technical field of macro-micro force measurement. Two force measuring units with piezoelectric ceramics as sensitive elements and a piezoelectric quartz reference unit with a piezoelectric quartz wafer as a sensitive element are used as sensors, the piezoelectric quartz reference unit is used for measuring macroscopic force, the force measuring units are used for measuring micro force, and continuous quasi-static measurement of the micro force can be realized through alternation of the two force measuring units. The resolution of the sensor is improved by utilizing the characteristic of high sensitivity of piezoelectric ceramics; and the stability of the sensor is improved by utilizing the characteristics of good linearity, high temperature stability and no hysteresis of piezoelectric quartz. Two indexes of high precision and wide range of the force sensor can be considered, multi-range quasi-static macro-micro force measurement is realized, and the force sensor has the advantages of high rigidity, high frequency response and the like.

Description

Technical Field

[0001] The invention relates to a piezoelectric macro-micro force sensing device and a measuring method, belonging to the technical field of macro-micro force measurement. Background Art

[0002] In modern industry and scientific research, force sensors are increasingly used in industrial automation, medical, aerospace and other fields. With the deepening of research, the demand for measuring and monitoring tiny forces in the fields of precision measurement, precision machining, material research, biomechanics, etc. is increasing.

[0003] Current force sensors often cannot take into account both high precision and large range, and there are some limitations when measuring tiny forces, such as low sensitivity, bulky size, long response time, etc. The invention patent "Multi-range macro-micro force sensor" with publication number CN103575436A realizes the measurement of multi-range macro-micro forces by pasting strain gauges on elastic sheets with different rigidity. This macro-micro force measurement sensor has weak rigidity and is easily damaged when subjected to large forces. It has the disadvantages of weak rigidity and low frequency response during force measurement. Therefore, a new type of macro-micro force sensing device is needed to solve these problems.

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

[0005] However, existing commercial piezoelectric force sensors mainly use piezoelectric quartz as the sensitive element, which has problems in dealing with the simultaneous measurement of macroscopic and microscopic forces. Under macroscopic forces, piezoelectric quartz can provide high-precision and high-sensitivity measurement results, without hysteresis and with high temperature stability. However, when it is necessary to measure microscopic forces, the sensitivity and resolution of the sensor will be limited and cannot meet the requirements of accurate measurement.

[0006] In contrast, piezoelectric ceramics have a higher piezoelectric coefficient, a compact structure, and high sensitivity. They can generate distinguishable charges under the action of tiny forces, and can be used to measure tiny forces and improve the accuracy of force sensors. However, the insulation impedance of piezoelectric ceramics is much smaller than that of piezoelectric quartz, and the charge leakage problem is serious. There are also problems such as hysteresis and poor temperature stability, which makes it difficult to detect tiny quasi-static forces and meet the needs of quasi-static measurement of tiny forces. Summary of the invention

[0007] In view of the problem that existing force sensors are difficult to meet the requirements of quasi-static measurement of tiny forces, the present invention provides a piezoelectric macro-micro force sensing device and a measurement method.

[0008] A piezoelectric macro-micro force sensing device and a measuring method of the present invention,

[0009] It 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 single chip microcomputer and a processing module;

[0010] Both force measuring unit I and force measuring unit II use piezoelectric ceramics as sensitive elements;

[0011] The piezoelectric quartz reference unit uses a piezoelectric quartz wafer as the sensitive element;

[0012] The processing module is used to output a control signal to the single-chip microcomputer, and control the measurement states of the charge amplifier I, the charge amplifier II, and the charge amplifier III through the single-chip microcomputer, wherein the measurement states include reset, dynamic, and quasi-static;

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

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

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

[0016] Preferably, the force measuring unit I comprises a No. 1 electrode sheet 2, a No. 1 piezoelectric ceramic sheet 3 and a No. 2 electrode sheet 4;

[0017] The positive electrode of the No. 1 piezoelectric ceramic sheet 3 is in contact with the No. 1 electrode sheet 2, and the negative electrode of the No. 1 piezoelectric ceramic sheet 3 is in contact with the No. 2 electrode sheet 4. The No. 1 electrode sheet 2 and the No. 2 electrode sheet 4 are the positive and negative output terminals of the force measuring unit I.

[0018] The force measuring unit II includes a No. 3 electrode sheet 6, a No. 2 piezoelectric ceramic sheet 7 and a No. 4 electrode sheet 8;

[0019] The positive electrode of the No. 2 piezoelectric ceramic sheet 7 contacts the No. 3 electrode sheet 6 , and the negative electrode of the No. 2 piezoelectric ceramic sheet 7 contacts the No. 4 electrode sheet 8 . The No. 3 electrode sheet 6 and the No. 4 electrode sheet 8 are the positive and negative output terminals of the force measuring unit II.

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

[0021] The X0 piezoelectric quartz upper wafer 11 and the X0 piezoelectric quartz lower wafer 13 are arranged with their negative electrodes facing each other, and their Y axes are arranged at 180 degrees relative to each other;

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

[0023] Preferably, polytetrafluoroethylene sheets are used to insulate between the force measuring unit I and the force measuring unit II, and between the force measuring unit II and the piezoelectric quartz reference unit.

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

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

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

[0027] S1, charge amplifier I, charge amplifier II, and charge amplifier III are all in quasi-static mode, controlling force measuring unit I and force measuring unit II to perform alternating measurements. The duration of a single measurement of 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, resetting the charge amplifier I, charge amplifier II and charge amplifier III, setting the sensitivity coefficient and gain multiple of each charge amplifier, and normalizing the force signals output by the 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 measurement of charge amplifier I is recorded as T 11 , the end time is recorded as T 12 , calculate (T 11 +Δt) time period, the average value of the respective sampling points of charge amplifier I and charge amplifier III Calculate (T 12 -Δt) The average value of the sampling points of charge amplifier I and charge amplifier III during the time period

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

[0031] S5. In T 11 ~T 12 Time period, the force signal F1 output by the charge amplifier I is processed: the data after shaping t represents time;

[0032] S6. The start time of a measurement of charge amplifier II is recorded as T 21 , the end time is recorded as T 22 , calculate (T 21 +Δt) time period, the average value of the respective sampling points of charge amplifier II and charge amplifier III Calculate (T 22 -Δt) The average value of the sampling points of charge amplifier II and charge amplifier III during the time period

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

[0034] S8, in T 21 ~T 22 Time period, the force signal F2 output by the charge amplifier II is processed: the data after shaping

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

[0036] S10. Repeat S3 to S9 to achieve alternating measurement.

[0037] Preferably, when measuring tiny dynamic forces, charge amplifier I and charge amplifier II are both 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 perceived tiny dynamic force.

[0038] Preferably, when measuring macroscopic quasi-static force, the charge amplifier III is in quasi-static mode and the piezoelectric quartz reference unit works alone.

[0039] Preferably, when measuring macroscopic dynamic force, the charge amplifier III is in dynamic mode and the piezoelectric quartz reference unit works alone.

[0040] Preferably, when measuring the preload force, the macroscopic force is determined based on the force signal output by the piezoelectric quartz reference unit; after the preload force loading is completed, the quasi-static force from micro to macroscopic is measured as required.

[0041] The beneficial effects of the present invention are as follows: by combining piezoelectric ceramics and piezoelectric quartz, the present invention can perform macroscopic measurements in a large force range and achieve high-sensitivity measurements in a small force range, thus meeting a wide range of application scenarios. The piezoelectric quartz crystal group of the present invention provides excellent temperature stability and linearity, and the high sensitivity of piezoelectric ceramics greatly improves the resolution of small force measurements. The present invention achieves quasi-static measurement of small forces by alternating two pieces of piezoelectric ceramics, overcoming the charge leakage and hysteresis problems of traditional piezoelectric ceramics in quasi-static measurements. Compared with traditional flexible structure sensors, the present invention adopts 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 needs. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0044] Figure 3 This is the flow chart of the first quasi-static alternating measurement of tiny force signals;

[0045] Figure 4 Schematic diagram of the principle of the quasi-static measurement algorithm of tiny force signals based on alternating measurement. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0048] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present 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 single chip microcomputer and a processing module;

[0050] Both force measuring unit I and force measuring unit II use piezoelectric ceramics as sensitive elements; piezoelectric ceramics have high piezoelectric coefficients and can keenly capture tiny force signals;

[0051] The piezoelectric quartz reference unit uses a piezoelectric quartz wafer as the sensitive element;

[0052] The piezoelectric quartz reference unit continuously measures macroscopic forces and plays a key 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 works alone.

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

[0054] The force measuring unit I comprises a No. 1 electrode sheet 2, a No. 1 piezoelectric ceramic sheet 3 and a No. 2 electrode sheet 4;

[0055] The positive electrode of the No. 1 piezoelectric ceramic sheet 3 is in contact with the No. 1 electrode sheet 2, and the negative electrode of the No. 1 piezoelectric ceramic sheet 3 is in contact with the No. 2 electrode sheet 4. The No. 1 electrode sheet 2 and the No. 2 electrode sheet 4 are the positive and negative output terminals of the force measuring unit I, and are respectively connected to the input terminal of the charge amplifier I through the coaxial cable shielding layer and the wire core after the lead connector 18;

[0056] The force measuring unit II includes electrode sheet No. 3 6, piezoelectric ceramic sheet No. 2 7 and electrode sheet No. 4 8; the positive pole of piezoelectric ceramic sheet No. 2 7 contacts electrode sheet No. 3 6, and the negative pole of piezoelectric ceramic sheet No. 2 7 contacts electrode sheet No. 4 8. Electrode sheet No. 3 6 and electrode sheet No. 4 8 are the positive and negative output terminals of the force measuring unit II, which are connected to the input terminal of the charge amplifier II through the coaxial cable shielding layer and the wire core after passing through the lead connector 18.

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

[0058] The X0 piezoelectric quartz upper wafer 11 and the X0 piezoelectric quartz lower wafer 13 are arranged with their negative electrodes facing each other, and the Y axes are arranged at 180 degrees relative to each other, forming a piezoelectric quartz crystal group;

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

[0060] The force measuring unit I and the force measuring unit II are coaxially arranged with the piezoelectric quartz reference unit, so that the external forces sensed are equal;

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

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

[0063] The processing module is used to output a control signal to the single-chip microcomputer, and control the measurement states of the charge amplifier I, the charge amplifier II, and the charge amplifier III through the single-chip microcomputer, wherein the measurement states include reset, dynamic, and quasi-static;

[0064] The outputs of the 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, and the processing module determines the macro force and the micro force according to the input.

[0065] Good insulation can avoid signal interference between components. The force measuring unit I and the force measuring unit II are insulated by a No. 1 polytetrafluoroethylene sheet 5, and the force measuring unit II and the piezoelectric quartz reference unit are insulated by a No. 2 polytetrafluoroethylene sheet 9. The internal components are insulated by polytetrafluoroethylene sheets to ensure electrical isolation between the piezoelectric components. At the same time, the sensor housing made of rigid materials ensures the overall rigidity and durability of the sensor, effectively avoiding deformation and structural failure that may occur during the measurement process.

[0066] The sensor housing is composed 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 the preload force is applied, the sensor cover 1 and the sensor base 17 are welded and packaged using an electron beam.

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

[0068] The piezoelectric macro-micro force sensing device of this embodiment can measure macro force, micro quasi-static force and micro dynamic force. When performing high-precision micro quasi-static force measurement in a large range and small fluctuation range, the force measuring unit I and the force measuring unit II have a smaller range and the piezoelectric quartz reference unit has a larger range. When measuring a large static force in the early stage, the output is the force signal of the piezoelectric quartz reference unit to obtain the macro force; after the preload force loading is completed, the high-precision measurement of micro force fluctuations is started, and the output is a composite of the force signals of the force measuring unit I, the force measuring unit II and the piezoelectric quartz reference unit, which can measure micro to macro quasi-static forces according to needs.

[0069] When measuring tiny 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 dynamic force signals of force measuring unit I and force measuring unit II are weighted 50% each as output;

[0070] When measuring small quasi-static forces, 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 single-chip microcomputer, and collects the voltage signals of force measuring unit I, force measuring unit II and piezoelectric quartz reference unit through a data acquisition card.

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

[0073] Step 2, reset the charge amplifier I, charge amplifier II and charge amplifier III, set the sensitivity coefficient and gain multiple of each charge amplifier, and normalize the force signals output by the charge amplifier I, charge amplifier II and charge amplifier III, that is, divide them by the gain multiple of each charge amplifier to obtain the force signals of all channels;

[0074] Step 3: The start time of a measurement of charge amplifier I is recorded as T 11 , the end time is recorded as T 12 , calculate (T 11 +Δt) time period, the average value of the respective sampling points of charge amplifier I and charge amplifier III Calculate (T 12 -Δt) The average value of the sampling points of charge amplifier I and charge amplifier III during the time period

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

[0076] Step 5: In T 11 ~T 12 Time period, the force signal F1 output by the charge amplifier I is processed: the data after shaping t represents time;

[0077] Step 6: The start time of a measurement of the charge amplifier II is recorded as T 21 , the end time is recorded as T 22 , calculate (T 21 +Δt) time period, the average value of the respective sampling points of charge amplifier II and charge amplifier III Calculate (T 22 -Δt) The average value of the sampling points of charge amplifier II and charge amplifier III during the time period

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

[0079] Step 8: In T 21 ~T 22 Time period, the force signal F2 output by the charge amplifier II is processed: the data after shaping

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

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

[0082] When measuring macroscopic quasi-static force, the charge amplifier III is in quasi-static mode and the piezoelectric quartz reference unit works alone.

[0083] When measuring macroscopic dynamic force, the charge amplifier III is in dynamic mode and the piezoelectric quartz reference unit works alone.

[0084] In this embodiment, when performing small-range high-precision quasi-static force measurement, the ranges of the high-resolution measurement module and the piezoelectric quartz reference unit are very small to ensure high sensitivity, and when the signal of the charge amplifier I and the charge amplifier II exceeds 80% of the current range, the reset function will be triggered in advance, and the other charge amplifier will continue to measure, thereby enhancing the continuity of the measurement;

[0085] In this embodiment, two piezoelectric ceramics and a piezoelectric quartz crystal group are connected in series as a sensor. The piezoelectric quartz crystal group is used to measure macro-force, and the piezoelectric ceramics are used to measure micro-force. The two piezoelectric ceramics can be used to alternately realize continuous quasi-static measurement of micro-force. The high sensitivity of piezoelectric ceramics is used to improve the resolution of the sensor; the good linearity, high temperature stability, and no hysteresis of piezoelectric quartz are used to improve the stability of the sensor. The present invention can take into account the two indicators of high precision and large range of force sensors, realize the measurement of multi-range quasi-static macro-micro forces, and has the advantages of high stiffness and high frequency response.

[0086] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A piezoelectric macro-micro force sensing device, characterized in that: It 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 single chip microcomputer and a processing module; Both force measuring unit I and force measuring unit II use piezoelectric ceramics as sensitive elements; The piezoelectric quartz reference unit uses a piezoelectric quartz wafer as the sensitive element; The processing module is used to output a control signal to the single-chip microcomputer, and control the measurement states of the charge amplifier I, the charge amplifier II, and the charge amplifier III through the single-chip microcomputer, wherein the measurement states include reset, dynamic, and quasi-static; The piezoelectric quartz reference unit continuously measures the macroscopic quasi-static force or macroscopic dynamic force; When measuring tiny quasi-static force signals, force measuring unit I and force measuring unit II work alternately, and there is an overlap time during each alternating measurement; The measurement results of the force measuring unit I, the force measuring unit II and the piezoelectric quartz reference unit are respectively input into the charge amplifier I, the charge amplifier II and the charge amplifier III, the outputs of the charge amplifier I, the charge amplifier II and the charge amplifier III are simultaneously input into the data acquisition card, the output of the data acquisition card is input into the processing module, and the processing module determines the macroscopic quasi-static force, the macroscopic dynamic force, the microscopic quasi-static force or the microscopic dynamic force according to the input.

2. The piezoelectric macro-micro force sensing device according to claim 1, characterized in that: The force measuring unit I includes electrode sheet No. 1, piezoelectric ceramic sheet No. 1 and electrode sheet No. 2; The positive electrode of the No. 1 piezoelectric ceramic sheet contacts the No. 1 electrode sheet, and the negative electrode of the No. 1 piezoelectric ceramic sheet contacts the No. 2 electrode sheet. The No. 1 electrode sheet and the No. 2 electrode sheet are the positive and negative output terminals of the force measuring unit I. The force measuring unit II includes electrode sheet No. 3, piezoelectric ceramic sheet No. 2 and electrode sheet No. 4; The positive electrode of the No. 2 piezoelectric ceramic sheet contacts the No. 3 electrode sheet, the negative electrode of the No. 2 piezoelectric ceramic sheet contacts the No. 4 electrode sheet, and the No. 3 electrode sheet and the No. 4 electrode sheet are the positive and negative output terminals of the 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 sheet, an X0 piezoelectric quartz upper wafer, a middle electrode sheet, an X0 piezoelectric quartz lower wafer, and a lower electrode sheet; The X0 piezoelectric quartz upper wafer and the X0 piezoelectric quartz lower wafer are arranged with their negative electrodes facing each other, and the Y axes are arranged at 180 degrees relative to each other; The upper electrode sheet and the lower electrode sheet are connected by a wire as the positive output terminal of the piezoelectric quartz reference unit, and the middle electrode sheet is used 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 by polytetrafluoroethylene sheets respectively.

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

6. A method for measuring a piezoelectric macro-micro force sensing device, characterized in that: When measuring small quasi-static forces, measurement methods include: S1, charge amplifier I, charge amplifier II, and charge amplifier III are all in quasi-static mode, controlling force measuring unit I and force measuring unit II to perform alternating measurements. The duration of a single measurement of 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, resetting the charge amplifier I, charge amplifier II and charge amplifier III, setting the sensitivity coefficient and gain multiple of each charge amplifier, and normalizing the force signals output by the charge amplifier I, charge amplifier II and charge amplifier III to obtain the force signals of all channels; S3. The start time of a measurement of charge amplifier I is recorded as T 11 , the end time is recorded as T 12 , calculate (T 11 +Δt) time period, the average value of the respective sampling points of charge amplifier I and charge amplifier III Calculate (T 12 -Δt) The average value of the sampling points of charge amplifier I and charge amplifier III during the time period S4. Calculate the slope difference between charge amplifier I and charge amplifier III S5. In T 11 ~T 12 Time period, the force signal F1 output by the charge amplifier I is processed: the data after shaping t represents time; S6. The start time of a measurement of charge amplifier II is recorded as T 21 , the end time is recorded as T 22 , calculate (T 21 +Δt) time period, the average value of the respective sampling points of charge amplifier II and charge amplifier III Calculate (T 22 -Δt) The average value of the sampling points of charge amplifier II and charge amplifier III during the time period S7. Calculate the slope difference between charge amplifier II and charge amplifier III S8, in T 21 ~T 22 Time period, the force signal F2 output by the charge amplifier II is processed: the data after shaping S9, with Δt / 2 as the boundary, in (T 11 +Δt / 2)~(T 12 -Δt / 2) time period As a small quasi-static force is perceived, at (T 21 +Δt / 2)~(T 22 -Δt / 2) time period The perceived tiny quasi-static force; S10. Repeat S3 to S9 to achieve alternating measurement.

7. The measuring method according to claim 6, characterized in that: When measuring tiny 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 perceived tiny dynamic force.

8. The measuring method according to claim 6, characterized in that: When measuring macroscopic quasi-static force, the charge amplifier III is in quasi-static mode and the piezoelectric quartz reference unit works alone.

9. The measuring method according to claim 6, characterized in that: When measuring macroscopic dynamic force, the charge amplifier III is in dynamic mode and the piezoelectric quartz reference unit works alone.

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

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