Adjustable weak coupling micro pressure sensor and closed loop control and temperature compensation method

Abstract

The application provides a weak coupling micro pressure sensor and a closed loop control and temperature compensation method, which can meet the requirement of micro pressure measurement in a wide temperature range. The structure of the application is very easy to adjust, and the coupling stiffness of the weak coupling resonator is adjusted on the basis of ensuring differential sensitivity. The application adopts a constant amplitude excitation scheme, adds a phase detector to further improve the stability of the closed loop control, and uses the amplitude signal of the resonator not affected by the alternating excitation as the reference signal of the phase detector, so as to lock the mode of the coupling resonator to the working mode. The sum of the displacements of the two resonators is used for representing the ambient temperature, so as to compensate the temperature characteristics of the sensor and realize the decoupling of the sensor output and the temperature.

Description

Technical Field

[0001] This invention belongs to the field of MEMS sensor design and control, specifically relating to an easily adjustable weakly coupled micro-pressure sensor and a closed-loop control and temperature compensation method. Background Technology

[0002] Weakly coupled resonant sensors are a type of resonant sensor, named for the fact that the stiffness of the coupling structure is much smaller than that of a single resonator. Compared to traditional frequency-output resonant sensors, they are known for their high sensitivity. Applying them to micro-pressure sensors aims to achieve even higher pressure resolution. Traditional resonant sensors use frequency as the output quantity, while in weakly coupled sensors, the frequency typically has low sensitivity to the measurand, but the resonator amplitude has high sensitivity. Therefore, amplitude-related dependent variables are usually chosen as the output quantity. A comparative analysis published in the Journal of Microelectromechanical Systems in 2016 by Zhao et al., titled "A comparative study of output metrics for an MEMS resonant sensor consisting of three weakly coupled resonators," showed that using the amplitude-to-signal ratio of the main resonators (amplitude ratio) as the output quantity has significant advantages in signal-to-noise ratio, common-mode rejection ratio, and sensitivity. Subsequent studies have generally chosen the amplitude ratio as the output quantity, and this invention follows suit. The sensitivity S when using the amplitude ratio as the output... AR As shown in formula (1), where Δk is the change in equivalent stiffness of the resonator caused by the pressure to be measured, k c Let represent the coupling stiffness of the coupled structure. From this equation, it can be seen that to improve the pressure sensitivity of the sensor, one approach is to increase the equivalent stiffness change of the single resonator caused by the measured pressure, and another is to design a weakly coupled structure to reduce the coupling stiffness. Previous schemes tended to place the resonator in the region of maximum strain on the pressure-sensitive membrane, neglecting differential sensitivity and ignoring the amplification effect of differential on sensitivity and the suppression of common-mode interference. Furthermore, existing research shows that the sensitivity of weakly coupled sensors is positively correlated with the degrees of freedom of the coupled system; however, to reduce complexity and improve reliability, only a two-degree-of-freedom system is usually chosen.

[0003]

[0004] For sensors that rely on pressure-sensitive membranes to sense pressure, the membranes have regions dominated by positive stress and regions dominated by negative stress. To achieve differential sensitivity, the positions of the two single resonators on the membrane need to be adjusted so that their frequency sensitivities to pressure are equal in magnitude but opposite in sign. This requires the coupling structure to have sufficient adjustability to ensure that the resonators achieve weak coupling based on differential sensitivity. Previous solutions did not consider this issue, resulting in the differential mechanism not significantly canceling common-mode interference, which affects the measurement accuracy of the sensor over a wide temperature range.

[0005] Resonant sensors can improve their operational stability when operating in closed-loop control mode; however, weakly coupled resonant sensors, especially differentially sensitive weakly coupled sensors, have their own unique characteristics. Traditional resonant sensors generally employ control schemes based on constant-amplitude oscillations. However, in differentially sensitive weakly coupled sensors, the amplitudes of the two single resonators will exhibit large-scale variations, such as... Figure 1 As shown, forcibly using the original method will cause the sensor to produce uncertainty faults and lose differential effect, so other methods must be used to achieve closed-loop control.

[0006] Pressure sensors typically have certain requirements for operating temperature. However, current research on the temperature characteristics of weakly coupled sensors focuses on the impact of small-range temperature fluctuations on output characteristics. The tendency is to encapsulate the sensor's sensitive structure in a constant-temperature environment to solve this problem. This constant-temperature environment is achieved through additional heating components, which increases the complexity and power consumption of the system and limits the application of weakly coupled sensors in wide-temperature scenarios.

[0007] Existing weakly coupled resonant pressure sensor structures either fail to consider differential design or the unique characteristics of differential sensing structures in pressure sensors. The reasons are as follows: Differential sensing requires matching the sensitivities of two single resonators to pressure to achieve equal values ​​but opposite signs. This requirement dictates that the resonators must be located at specific positions on the pressure-sensitive membrane. However, to achieve weak coupling between the two single resonators, they must be connected via a microstructure. Traditional single-beam structures are difficult to meet these requirements, and the ability to adjust the coupling stiffness is very limited, significantly restricting improvements in sensor performance.

[0008] Traditional closed-loop control schemes based on constant amplitude oscillation of resonators limit the performance of differential sensing because they directly limit the amplitude of the resonator. This is also the reason why such closed-loop control introduces uncertainties, which may cause the sensor to malfunction.

[0009] Existing research can only demonstrate that weakly coupled sensors are insensitive to small-range ambient temperature fluctuations, i.e., they have strong common-mode rejection capabilities, but their application over a wide temperature range has not yet been mentioned. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention proposes an easily adjustable weakly coupled micro-pressure sensor, along with closed-loop control and temperature compensation methods, to meet the requirements for pressure measurement over a wide temperature range. The structure of this invention is highly adjustable, achieving a weakly coupled resonator with adjustable coupling stiffness while ensuring differential sensitivity. This invention employs a constant amplitude excitation scheme, and to further enhance the stability of the closed-loop control, a phase detector is added. The amplitude signal of the resonator not subjected to AC excitation is used as the reference signal for the phase detector, thereby locking the mode of the coupled resonator to the operating mode. This invention uses the sum of the displacements of the two resonators to characterize the ambient temperature, thus compensating for the sensor's temperature characteristics and eliminating the influence of temperature on the measured pressure value.

[0011] This invention proposes a temperature compensation scheme applicable to a wide temperature range of -20 to 60°C. The two single resonators adopt a differential sensitive design. The pressure to be measured will cause the two to produce equivalent stiffness changes of -Δk and Δk respectively. Temperature is a common-mode change, which causes both to produce equivalent stiffness changes of ΔkT. The influence of temperature is thus weakened.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] An easily adjustable weakly coupled micro-pressure sensor includes an easily adjustable weakly coupled resonator, which consists of two single resonators and a weak coupling structure. The single resonators are a first resonator and a second resonator. The first and second resonators are identical and interchangeable. Each of the first and second resonators includes an anchor point, a double-ended fixed-supported coupled beam resonator, a strain gauge piezoresistive vibration pickup structure, an electrostatic stiffness tuning structure, and an electrostatic drive structure. The electrostatic drive structure is connected in the middle of the double-ended fixed-supported coupled beam resonator and is used to drive the double-ended fixed-supported coupled beam resonator to vibrate. The strain gauge piezoresistive vibration pickup structure is located at the end of the double-ended fixed-supported coupled beam resonator. When the double-ended fixed-supported coupled beam resonator vibrates, it forces a change in the resistance of the strain gauge piezoresistive vibration pickup structure, thereby picking up vibration information. The first and second resonators are arranged parallel to each other along the length of a pressure-sensitive diaphragm and connected to the pressure-sensitive diaphragm via the anchor point. The two ends of the first connection end of the weak coupling structure are respectively connected to the anchor points near the first and second resonators.

[0014] Furthermore, the weak coupling structure includes a first coupling link, two parallel first connecting ends, and a support rod; first, the positions of the first resonator and the second resonator are adjusted to meet the differential sensitivity requirements, and then the weak coupling structure is added and its structural parameters are adjusted to achieve weak coupling.

[0015] Furthermore, the two parallel connection ends are positively parallel, and the out-of-phase mode frequency of the first-order mode of the coupled vibration of the first resonator and the second resonator is lower than that of the in-phase mode.

[0016] Furthermore, the two parallel first connection ends are antiparallel, and at this time the frequency of the antiphase mode of the first-order coupled vibration of the two single resonators is higher than that of the in-phase mode.

[0017] Furthermore, single resonators include double-ended fixed beam resonators and folded beam resonators.

[0018] Furthermore, the excitation and pickup structures of the resonator include electrostatic excitation and piezoresistive strain pickup, electrostatic excitation / capacitive pickup, or electromagnetic excitation / magnetic-electric detection.

[0019] This invention also discloses a closed-loop control method for an easily adjustable weakly coupled micro-pressure sensor, comprising:

[0020] Based on the constant excitation oscillation principle, the first and second resonators can be interchanged. The vibration displacement of the second resonator, which is not excited by the AC signal, is used as the reference phase and frequency reference of the phase detector. The vibration displacement signal of the first resonator, which receives the excitation signal, is first amplified by the pre-amplifier stage. Then, the phase of the output signal is adjusted by the phase shifter stage so that the initial phase difference between the output signal and the vibration displacement signal of the second resonator before it is connected to the phase detector is zero. The phase detector calculates the phase difference information and sends it to the voltage-controlled oscillation stage, which then generates the corresponding AC excitation signal.

[0021] This invention also discloses another closed-loop control method for an easily adjustable weakly coupled micro-pressure sensor, comprising:

[0022] It is implemented by a pre-amplifier stage and a voltage-controlled oscillator. Only one of the first and second resonators participates in closed-loop control. The vibration displacement signal of the resonator using closed-loop control is directly connected to the voltage-controlled oscillator after being processed by the pre-amplifier stage. The voltage-controlled oscillator generates a corresponding frequency excitation signal based on the amplitude of this vibration displacement signal. This frequency excitation signal is directly connected to the drive end of the resonator using closed-loop control, thereby achieving its stable vibration.

[0023] Furthermore, the closed-loop control method is used in scenarios involving differential and non-differential sensitive structures with weak coupling of two degrees of freedom.

[0024] This invention also discloses a temperature compensation method for an easily adjustable weakly coupled micro-pressure sensor, comprising the following steps: characterizing the temperature-induced shift in the resonator's vibration displacement signal through a component or measurable quantity, thereby calculating the temperature information, and then combining this with the resonator's vibration displacement signal to calculate the actual pressure value to be measured; using the sum of the vibration displacement signals of the two single resonators in the operating mode as temperature compensation, i.e., assuming the vibration displacement of the two single resonators in the in-phase mode is x. 1，i and x 2，i The vibration displacement in the reverse mode is x1，o and x 2，o The expressions for the variables used for temperature compensation are shown in equations (2) and (3). These two equations characterize the ambient temperature of the sensor, and are then combined with the amplitude ratio signal x. 1，i / x 2，i or x 1，o / x 2，o Obtaining the actual pressure signal to be measured, i.e., achieving compensation:

[0025] T i (·)=x 1，i +x 2，i (2)

[0026] T o (·)=x 1，o +x 2，o (3)

[0027] The operating mode is either in-phase or out-of-phase.

[0028] Beneficial effects:

[0029] 1. Based on the differential pressure sensitivity matching of two resonators, the coupling scheme proposed in this invention can easily form a weak coupling effect, that is, the coupling strength can be adjusted more easily without affecting the differential characteristics of the resonators. Furthermore, by changing the two coupling structures, the frequency of the in-phase mode of the weakly coupled resonator system can be adjusted to be higher or lower than the frequency of the out-of-phase mode. For example, when using the easily adjustable weak coupling first scheme, the frequency of the out-of-phase mode of the coupled resonator system is lower than that of the in-phase mode, while the easily adjustable weak coupling second scheme is the opposite.

[0030] 2. Previous closed-loop resonator schemes mostly adopted the constant amplitude oscillation principle. However, in wide-temperature-range differential weakly coupled sensors, the amplitudes of the two resonators may vary significantly, making the above scheme unsuitable. The constant amplitude excitation scheme proposed in this invention maintains constant excitation. A driving signal with the same frequency as the current resonator is generated by a voltage-controlled oscillator. To further improve stability, a phase detector is added, using the frequency signal of the second resonator as a phase reference to lock the vibration modes of the first and second resonators into the operating mode (in-phase or out-of-phase mode).

[0031] 3. Previous studies have not described compensation for the temperature characteristics of such sensors. The temperature compensation scheme proposed in this invention can be designed to have a single correspondence with all temperature and pressure test points, which can effectively characterize the temperature characteristics of weakly coupled pressure sensors and reduce the impact of temperature on the stability of the pressure test results. Attached Figure Description

[0032] Figure 1 The vibration displacement characteristics of a two-degree-of-freedom weakly coupled pressure sensor in the range of -20 to 60℃ are shown in the figure.

[0033] Figure 2 This is a schematic diagram of the first easily adjustable, weakly coupled scheme;

[0034] Figure 3 This is a schematic diagram of the easily adjustable, weakly coupled second scheme;

[0035] Figure 4 The block diagram of a two-degree-of-freedom weakly coupled sensor closed-loop control method is shown.

[0036] Figure 5 This is a block diagram of another closed-loop control method.

[0037] In the figure, 100-first resonator; 1-anchor point; 2-double-ended fixed-supported coupled beam resonator; 3-electrostatic drive structure; 4-electrostatic stiffness tuning structure; 6-strain gauge piezoresistive vibration pickup structure; 200-second resonator; 300-weakly coupled structure; 301-first coupling link; 302-first connecting end; 303-support rod; 400-coupled beam; 401-second coupling link; 402-second connecting end; 403-second support rod. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0039] This invention proposes an easily adjustable weakly coupled micro-pressure sensor and a closed-loop control and temperature compensation method to meet the needs of pressure measurement over a wide temperature range. In dual-resonator differential pressure sensors, to ensure the differential effect of the two resonators, their sensitivity to pressure must typically be numerically equal. This can be achieved by adjusting the position of the resonators on the pressure-sensitive membrane. Therefore, coupling with only a thin beam cannot meet the design requirements. This invention proposes a method such as… Figure 2 and Figure 3 Two easily adjustable coupled resonators address this problem. This invention also proposes a closed-loop control method suitable for the aforementioned easily adjustable coupled resonators, such as... Figure 4 As shown. In addition, this invention proposes a temperature compensation method that can meet the application requirements of a wide temperature range of -20 to 60°C.

[0040] like Figure 2As shown, the easily adjustable weakly coupled resonator of the present invention is suitable for weakly coupled micro-pressure sensors. This type of sensor senses the pressure to be measured through a diaphragm and senses the strain or stress of the diaphragm through a resonator anchored on the diaphragm. In the first embodiment, the easily adjustable weakly coupled resonator consists of two single resonators, namely a first resonator 100, a second resonator 200, and a weakly coupled structure 300. The first resonator 100 and the second resonator 200 are essentially the same and can be interchanged. Both the first resonator 100 and the second resonator 200 include an anchor point 1, a double-ended fixed coupled beam resonator 2, a strain gauge piezoresistive vibration pickup structure 6, an electrostatic stiffness tuning structure 4, and an electrostatic drive structure 3. The main structure of the first resonator 100 and the second resonator 200 is a double-ended fixed-support coupled beam resonator 2. The electrostatic drive structure 3 is connected in the middle of the double-ended fixed-support coupled beam resonator 2 to drive the vibration of the double-ended fixed-support coupled beam resonator 2. The strain gauge piezoresistive vibration pickup structure 6 is located at the end of the double-ended fixed-support coupled beam resonator 2. When the double-ended fixed-support coupled beam resonator 2 vibrates, it forces the resistance of the strain gauge piezoresistive vibration pickup structure 6 to change, thereby picking up vibration information. The first resonator 100 and the second resonator 200 are arranged parallel to each other along the length direction on the pressure-sensitive diaphragm and are connected to the pressure-sensitive diaphragm through the anchor point 1. The two ends of the first connection end 302 of the weak coupling structure 300 are respectively connected to the anchor point 1 near the first resonator 100 and the second resonator 200.

[0041] The weakly coupled structure 300 is further subdivided into a first coupling link 301, two parallel first connecting ends 302, and a support rod 303. One end of the support rod 303 is connected to the middle of the first coupling link 301, and the other end is connected to the pressure-sensitive membrane through an anchor point 1. The support rod 303 is connected to both ends of the first coupling link 301, and the other end is connected to the first resonator 100 and the second resonator 200, with the distance between the connection point and the anchor point 1 being 0.1 to 0.001 times the length of the double-ended fixed-supported coupled beam resonator 2. During the design process, the positions of the first resonator 100 and the second resonator 200 can be adjusted first to meet the differential sensitivity requirements. Then, a weak coupling structure 300 is added, and weak coupling is achieved by adjusting its structural parameters. With a constant structural thickness (depending on the thickness of the silicon-on-insulator device layer), the coupling stiffness can be weakened by increasing the length or decreasing the width of the support rod 303, increasing the length or decreasing the width of the first coupling link 301, or decreasing the distance from the connection point of the support rod 303 and the double-ended fixed-supported coupling beam resonator 2 to the anchor point 1, thus achieving weak coupling. In this scheme, the out-of-phase mode frequency of the first-order vibration of the coupled first resonator 100 and the second resonator 200 is lower than that of the in-phase mode.

[0042] like Figure 3As shown, in the second scheme, the basic structure of the easily adjustable weakly coupled resonator is exactly the same as that in the first scheme. It also consists of two single resonators without weak coupling characteristics, namely the first resonator 100 and the second resonator 200, and the coupling beam 400. The composition of the single resonators is exactly the same as that in the first scheme. The second support rod 403 is also connected to the middle of the second coupling link 401. However, at this time, the two second connecting ends 402 at the end of the second coupling link 401 of the coupling beam 400 are parallel in opposite directions. At this time, the frequency of the out-of-phase mode of the first-order coupled vibration of the two single resonators is higher than that of the in-phase mode.

[0043] like Figure 4 The diagram illustrates a closed-loop control method for the easily adjustable, weakly coupled micro-pressure sensor applicable to this invention. The closed-loop control method is designed based on constant-amplitude excitation oscillation. The positions of the first and second resonators can be interchanged. The resonator not excited by the AC signal (assuming it is...) Figure 4 The vibration displacement of the second resonator is used as the phase and frequency reference of the phase detector. The phase detector sends the phase difference information between the first and second resonators to the voltage-controlled oscillator (VCO) circuit, thereby generating a corresponding AC excitation signal to drive the first resonator and maintain its stable oscillation. In this method, the operating modes (in-phase or out-of-phase modes) of the two single resonators are no longer selected solely by the driving frequency, but can be further locked by the phase detector circuit, thus improving the vibration stability of the coupled system.

[0044] In the temperature compensation method of this invention, temperature compensation is achieved by using the sum of the vibration displacement signals of the two single resonators in their operating modes (in-phase or out-of-phase modes) as the temperature compensation. Specifically, it is assumed that the vibration displacement of the two single resonators in the in-phase mode is x. 1,i and x 2,i The vibration displacement in the reverse mode is x 1,o and x 2,o The variable temperature value T used for temperature compensation in the two working modes is... i (·) or T o The expression for (·) is shown in equations (2) and (3). The ambient temperature of the sensor can be calculated using this equation, thereby achieving compensation.

[0045] T i (·)=x 1，i +x 2，i (2)

[0046] T o (·)=x 1，o +x 2，o (3)

[0047] Preferably, the structure of a single resonator can be a double-ended fixed beam, a folded beam resonator, etc.

[0048] Preferably, the excitation and vibration pickup structure of the resonator is not limited to electrostatic excitation and piezoresistive strain vibration pickup, but can also be electrostatic excitation / capacitive vibration pickup, electromagnetic excitation / magnetic-electric detection, etc.

[0049] Preferably, the closed-loop control method can also consist of only a pre-amplifier stage and a voltage-controlled oscillator, such as... Figure 5 As shown, in this method, only one of the first and second resonators participates in closed-loop control. For ease of description, we focus on the first resonator. Its vibration displacement signal is directly connected to the voltage-controlled oscillator after being processed by the pre-amplifier stage. The voltage-controlled oscillator generates a corresponding frequency excitation signal based on the amplitude of this displacement signal. This excitation signal is connected to the drive end of the first resonator, thereby realizing the stable vibration of the resonator.

[0050] Preferably, the closed-loop control method can also be used in non-differential sensitive scenarios, as long as it is a sensitive structure with two degrees of freedom and weak coupling.

[0051] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An easily adjustable weakly coupled micro-pressure sensor, characterized in that, The system includes an easily adjustable weakly coupled resonator, which consists of two single resonators and a weak coupling structure. The single resonators are a first resonator and a second resonator. The first and second resonators are identical and interchangeable. Each of the first and second resonators includes an anchor point, a double-ended fixed-support coupled beam resonator, a strain gauge piezoresistive vibration pickup structure, an electrostatic stiffness tuning structure, and an electrostatic drive structure. The electrostatic drive structure is connected in the middle of the double-ended fixed-support coupled beam resonator and is used to drive its vibration. The strain gauge piezoresistive vibration pickup structure is located at the end of the double-ended fixed-support coupled beam resonator. When the double-ended fixed-support coupled beam resonator vibrates, it forces a change in the resistance of the strain gauge piezoresistive vibration pickup structure, thereby picking up vibration information. The first and second resonators are arranged parallel to each other along their length on a pressure-sensitive diaphragm and connected to the pressure-sensitive diaphragm via anchor points. The two ends of the first connection end of the weak coupling structure are connected to the anchor points near the first and second resonators, respectively. When the two parallel connection ends are positively parallel, the out-of-phase mode frequency of the first-order vibration mode of the first resonator and the second resonator is lower than that of the in-phase mode; or when the two parallel first connection ends are negatively parallel, the out-of-phase mode frequency of the first-order vibration mode of the two single resonators is higher than that of the in-phase mode. The temperature-induced shift in the resonator's vibration displacement signal is characterized by a component or measurable quantity, thereby calculating the temperature information. This temperature information is then combined with the resonator's vibration displacement signal to calculate the actual measured pressure value. The sum of the vibration displacement signals of the two single resonators in the operating mode is used for temperature compensation; that is, assuming the vibration displacement of the two single resonators in the in-phase mode is... and The vibration displacement in the reverse mode is and The variable used for temperature compensation is obtained, and the ambient temperature of the sensor is characterized by two equations, which are then combined with the amplitude ratio signal. or Compensation can be achieved by obtaining the actual pressure signal to be measured.

2. The easily adjustable weakly coupled micro-pressure sensor according to claim 1, characterized in that, The weak coupling structure includes a first coupling link, two parallel first connecting ends, and a support rod; first, adjust the positions of the first resonator and the second resonator to meet the differential sensitivity requirements, and then add the weak coupling structure to achieve weak coupling by adjusting its structural parameters.

3. The easily adjustable weakly coupled micro-pressure sensor according to claim 1, characterized in that, Single resonators include double-ended fixed beam resonators and folded beam resonators.

4. The easily adjustable weakly coupled micro-pressure sensor according to claim 1, characterized in that, The excitation and pickup structures of resonators include electrostatic excitation and piezoresistive strain pickup, electrostatic excitation / capacitive pickup, or electromagnetic excitation / magnetic-electric detection.

5. A closed-loop control method for an easily adjustable weakly coupled micro-pressure sensor according to any one of claims 1-4, characterized in that, include: Operating based on constant excitation oscillation, the first and second resonators can be interchanged. The vibration displacement of the second resonator, which is not excited by the AC signal, is used as the phase reference and frequency reference of the phase detector. The vibration displacement signal of the first resonator, which receives the excitation signal, is first amplified by the pre-amplifier stage, and then the phase of the output signal is adjusted by the phase shifter stage so that the initial phase difference between it and the vibration displacement signal of the second resonator before it is connected to the phase detector is zero. The phase detector calculates the phase difference information and sends it to the voltage-controlled oscillator stage, which then generates the corresponding AC excitation signal.

6. A closed-loop control method for an easily adjustable weakly coupled micro-pressure sensor according to any one of claims 1-4, characterized in that, include: It is achieved by only a pre-amplifier stage and a voltage-controlled oscillator. Only one of the first and second resonators participates in closed-loop control. The vibration displacement signal of the resonator participating in closed-loop control is directly connected to the voltage-controlled oscillator after being processed by the pre-amplifier stage. The voltage-controlled oscillator generates a corresponding frequency excitation signal based on the amplitude of this vibration displacement signal. This frequency excitation signal is connected to the drive end of the resonator using closed-loop control, thereby achieving its stable vibration.

7. The closed-loop control method according to claim 5 or 6, characterized in that, The closed-loop control method is used in scenarios involving differential or non-differential sensitive structures with weak coupling and two degrees of freedom.

8. A temperature compensation method for an easily adjustable weakly coupled micro-pressure sensor according to any one of claims 1-4, characterized in that, This includes the following: Characterizing the temperature-induced shift in the resonator's vibration displacement signal using a component or measurable quantity, thereby calculating the temperature information, and then combining this with the resonator's vibration displacement signal to calculate the actual pressure value to be measured; using the sum of the vibration displacement signals of the two single resonators in the operating mode as temperature compensation, i.e., assuming the vibration displacement of the two single resonators in the in-phase mode is... and The vibration displacement in the reverse mode is and The expressions for the variables used for temperature compensation are shown in equations (2) and (3). These two equations characterize the ambient temperature of the sensor, and are then combined with the amplitude ratio signal. or Compensation can be achieved by obtaining the actual pressure signal to be measured: (2) (3) The operating mode is either in-phase or out-of-phase.

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