A scale factor adjustable electromagnetic feedback sensor and method of adjustment

Abstract

The application belongs to the field of electromagnetic feedback sensors, and specifically discloses a scale factor adjustable electromagnetic feedback sensor and an adjusting method. In the application, a sensitive probe is used to convert a displacement signal into a voltage through a sensing module, and then an adjustable resistor in a feedback execution machine is output by a feedback control module to drive. By changing the resistance value, the feedback gain is continuously adjusted, and by changing the resistance value of the adjustable resistor of the pressure-flow conversion unit in the feedback execution machine, the feedback execution machine gain is adjusted, so as to adjust the scale factor of the sensor online. This closed-loop structure enables the feedback force to drive the sensitive mass back in real time, effectively suppresses the translational and rotational noise interference of the carrier environment, and significantly improves the measurement stability. For the multi-sensor linkage scene, only the adjustable resistance values of the sensors need to be adjusted to unify the scale factor. Compared with the prior art, the present scheme realizes flexible adjustment of the scale factor and accurate matching of multiple sensors, and improves the system anti-interference ability and cooperative working precision.

Description

Technical Field

[0001] This application belongs to the field of electromagnetic feedback sensors, specifically relating to an electromagnetic feedback sensor with adjustable scaling factor and an adjustment method. Background Technology

[0002] Electromagnetic feedback can provide a large feedback force and is a common closed-loop control method for force-balanced sensors. The scaling factor is one of the core parameters of a sensor. Due to limitations in manufacturing processes, there is always a certain degree of inconsistency in the scaling factors between individual sensors. Therefore, in some precision measurement applications, especially those involving differential measurements with two or more sensors, it is generally required that the consistency of the differential sensor scaling factors be as accurate as possible, or that the scaling factors have the ability to be adjusted online with high precision.

[0003] For example, a rotating accelerometer gravity gradiometer can acquire gravity gradient signals using differential modulation of four electromagnetic feedback accelerometers. Ideally, the scaling factors of the four accelerometers should be completely identical to suppress interference from translational and rotational noise in the carrier environment. However, since the scaling factors of the four accelerometers cannot be completely identical, it is necessary to introduce an online scaling factor adjustment method to precisely match the scaling factors of the four accelerometers, thereby achieving high-precision measurement of the gravity gradient signal. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this application is to provide an electromagnetic feedback sensor with an adjustable scaling factor and an adjustment method, aiming to solve the problems of lacking a solution to achieve consistent scaling factors in scenarios involving the coordinated use of multiple sensors, and the existence of interference from translational and rotational noise in the carrier environment.

[0005] The first aspect of this application relates to an electromagnetic feedback sensor with an adjustable scaling factor, comprising: a sensitive probe for converting a measured parameter into a displacement signal of a sensitive mass; a sensing module connected to the sensitive probe for converting the displacement signal into a voltage signal; a feedback control module connected to the sensing module for receiving the voltage signal and outputting a feedback control signal; and a feedback actuator module connected to the feedback control module for receiving the feedback control signal and generating a feedback force to drive the sensitive mass back to its equilibrium position; wherein the feedback actuator module includes at least one adjustable resistor, and the feedback gain is adjusted by changing the resistance value of the adjustable resistor to change the scaling factor of the sensor.

[0006] In one embodiment, the feedback actuator module further includes: a voltage drive unit, a voltage-to-current conversion unit, and a feedback coil; the output terminal of the feedback control module is connected to the input terminal of the voltage drive unit, the output terminal of the voltage drive unit is connected to the input terminal of the voltage-to-current conversion unit, and the output terminal of the voltage-to-current conversion unit is connected to the feedback coil; the voltage drive unit is configured to receive a feedback control signal, and after amplifying or buffering the feedback control signal, provide a drive voltage to the voltage-to-current conversion unit; the voltage-to-current conversion unit is configured to convert the drive voltage into an excitation current and output it to the feedback coil; the feedback coil is used to generate a feedback force proportional to the excitation current and act on the sensitive mass.

[0007] In one embodiment, the voltage-to-current conversion unit includes at least one adjustable resistor and at least one fixed resistor; the adjustable resistor and the fixed resistor are connected in series and / or in parallel between the voltage drive unit and the feedback coil.

[0008] In one embodiment, the voltage-to-current conversion unit includes: a first fixed resistor, a second fixed resistor, and an adjustable resistor; the first fixed resistor and the adjustable resistor are connected in parallel; the first parallel terminal is connected to the second terminal of the second fixed resistor; the second parallel terminal is connected to the feedback coil; and the first terminal of the second fixed resistor is connected to the output terminal of the voltage drive unit.

[0009] In one embodiment, the voltage-to-current conversion unit includes: a first fixed resistor and two adjustable resistors; the first fixed resistor and either adjustable resistor are connected in parallel; the first terminal of the parallel connection is connected to the second terminal of the other adjustable resistor; the second terminal of the parallel connection is connected to a feedback coil; and the first terminal of the other adjustable resistor is connected to the output terminal of the voltage drive unit.

[0010] In one embodiment, the scaling factor of the sensor K The expression is: Among them, by changing the voltage-to-current conversion resistor R e To achieve adjustment of the scaling factor; m For quality that is sensitive to quality; L The length of the electromagnetic coil; B The magnetic field in which the sensitive mass is located.

[0011] In one embodiment, the adjustable resistor is adjusted by means of a rotary motor adjustment mechanism or a digital control potentiometer.

[0012] In one embodiment, the sensitive probe is a variable-gap capacitive accelerometer sensitive probe or a variable-area capacitive accelerometer sensitive probe.

[0013] The second aspect of this application relates to a multi-sensor measurement system, comprising: at least two electromagnetic feedback sensors with adjustable scaling factors as described in the first aspect; wherein the adjustable resistance of each sensor is independently adjusted to match the scaling factors of each sensor.

[0014] The third aspect of this application relates to a scaling factor adjustment method, which applies the multi-sensor measurement system of the second aspect, including: acquiring the current target scaling factor; adjusting the resistance value of the adjustable resistors of each sensor based on the target scaling factor so that the scaling factors of each sensor are matched; and fusing the output signals of each sensor. This method can be widely used in differential sensor combination measurements, such as rotational accelerometer gravity gradient meters, to suppress common-mode noise.

[0015] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: This application employs a sensitive probe to convert the measured parameter into a displacement signal of the sensitive mass, and then converts this displacement signal into a voltage signal through a sensing module, thereby establishing an initial conversion relationship between physical quantities and electrical signals, providing a measurement basis for subsequent closed-loop control. Based on this, a feedback control module receives the voltage signal and outputs a feedback control signal, while a feedback actuator module receives the output voltage and generates a feedback force to drive the sensitive mass back to its equilibrium position. This constructs a complete electromagnetic feedback closed-loop system, enabling the sensor to cancel out translational and rotational noise interference introduced by the carrier environment in real time, significantly improving measurement stability.

[0016] Furthermore, since the feedback actuator module includes at least one adjustable resistor, the feedback gain can be continuously adjusted by changing the resistance value of the adjustable resistor, thereby directly changing the scaling factor of the sensor. Thus, for scenarios where multiple sensors are used in conjunction, there is no need to replace the hardware or redesign the circuit. The scaling factors of all sensors can be made consistent simply by adjusting the resistance values ​​of the adjustable resistors of each sensor. This effectively solves the system mismatch problem caused by the lack of a unified scaling factor adjustment scheme in the prior art.

[0017] Compared with existing technologies, this solution not only achieves online adjustment of the scaling factor and consistency matching of multiple sensors, but also enhances the ability to resist environmental noise by means of a closed-loop feedback mechanism, thereby improving the overall collaborative working accuracy and reliability of the sensor array. Attached Figure Description

[0018] Figure 1 A schematic diagram of an electromagnetic feedback sensor structure with adjustable scaling factor provided in an embodiment of this application; Figure 2 This is a schematic diagram illustrating a combination of adjustable resistor and fixed resistor provided in an embodiment of this application; Figure 3A schematic diagram illustrating yet another combination of adjustable resistor and fixed resistor provided in an embodiment of this application; Figure 4 This is a schematic diagram of the scale factor adjustment structure of the electromagnetic feedback metal reed capacitor accelerometer provided in the embodiments of this application; Figure 5 This is a schematic diagram of the scale factor adjustment structure of the electromagnetic feedback micromechanical capacitive accelerometer provided in an embodiment of this application.

[0019] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 100 is the sensitive probe; 200 is the sensing module; 300 is the feedback control module; 400 is the feedback actuator module; 500 is the voltage drive unit; 600 is the voltage-to-current conversion unit; 700 is the feedback coil; 101 is the micro-mechanical encapsulation wire bonding point; 201 is the sensitive probe frame; 202 is the fixed electrode plate; 203 is the sensitive mass; 205 is the mechanical spring; 206 is the permanent magnet; 207 is the metal coating on the moving electrode plate; 601 is the first fixed resistor; 602 is the second fixed resistor; 603 is the adjustable resistor. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. In this application, the symbol " / " indicates that the related objects are in an "or" relationship, for example, A / B means A or B.

[0022] In this application, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order of objects. For example, "first response message" and "second response message," etc., are used to distinguish different response messages, not to describe a specific order of response messages. The term "connection" in this application can refer to a direct circuit connection or signal transmission via a communication protocol.

[0023] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0024] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0025] Currently, in multi-sensor collaborative applications, such as inertial navigation systems, seismic monitoring arrays, or multi-axis vibration testing platforms, each sensor needs to maintain a high degree of consistency in its scaling factor to achieve data fusion and collaborative measurement. However, existing technologies lack an effective solution for uniformly adjusting or calibrating the scaling factors of multiple sensors.

[0026] It should be noted that the scaling factor refers to the ratio of the sensor output to the input measurand, and its consistency directly affects the overall accuracy of the measurement system. Meanwhile, in actual installation environments, sensors are subject to interference from the translational acceleration of the carrier (such as the inertial force generated by the linear motion of a vehicle) and rotational angular velocity (such as the Coriolis effect caused by rotational motion). This noise is superimposed on the displacement signal of the sensitive mass, leading to output distortion. Therefore, there is an urgent need for a sensor structure that can independently adjust the scaling factor while suppressing environmental mechanical noise.

[0027] Based on this, this application proposes an embodiment of an electromagnetic feedback sensor with an adjustable scaling factor. Its core lies in flexibly adjusting the gain of the feedback loop through electrical means, thereby changing the sensor's sensitivity, i.e., the scaling factor. Please refer to... Figure 1 , Figure 1 This is a schematic diagram of an electromagnetic feedback sensor structure with adjustable scaling factor provided in an embodiment of this application.

[0028] In this embodiment, the sensor includes: Sensitive probe 100 is used to convert the measured parameter into a displacement signal of the sensitive mass. Specifically, it converts the measured parameter (such as acceleration, angular velocity, pressure, etc.) into the mechanical displacement of the sensitive mass. The sensitive probe typically uses elastic support elements such as a quartz pendulum, silicon micromechanical structure, or metal cantilever beam, and the sensitive mass can be an inertial block or diaphragm integrated on the probe.

[0029] The sensing module 200, connected to the sensitive probe 100, is used to convert displacement signals into voltage signals. Specifically, it converts the displacement signal of the sensitive mass into a voltage signal. This module can employ capacitive displacement detection circuits (such as differential capacitor bridges + charge amplifiers), inductive displacement sensors, or optical interferometers, with typical components including variable-pitch capacitor plates, differential transformers, or photoelectric encoders.

[0030] The feedback control module 300, connected to the sensing module 200, receives voltage signals and outputs feedback control signals. This module typically includes a PID controller, a proportional-integral amplifier, or an analog compensation network, and its output... VoutAs the final measurement signal of the entire sensor, it also drives the subsequent actuators.

[0031] The feedback actuator module 400, connected to the feedback control module 300, receives feedback control signals and generates a feedback force to drive the sensitive mass 203 back to its equilibrium position. The direction of the feedback force is opposite to the externally applied measured force, thus achieving a force balance closed-loop operating mode.

[0032] In the above structure, the key is that the feedback actuator module 400 includes at least one adjustable resistor. This adjustable resistor is connected in series or parallel in the drive circuit of the feedback coil. By changing its resistance value through a manual knob, digital interface, or automatic calibration algorithm, the current flowing through the feedback coil can be adjusted, thereby changing the feedback torque coefficient (i.e., the feedback force corresponding to a unit output voltage).

[0033] It should be noted that the feedback actuator circuit drives the electromagnetic feedback coil, generating an Ampere force to maintain the sensitive mass of the sensitive probe at an equilibrium position, thus completing the feedback process. The Ampere force... F=BIL , B The steady magnetic field at the location of the coil. I To adjust the current, L The length of the coil is given. At this point, the feedback force applied to the sensitive mass by the feedback actuator is proportional to the measured physicochemical parameter. Therefore, the output voltage Vout can characterize the magnitude of the measured parameter, and the proportionality coefficient between the two is the scaling factor. K It can be simply expressed as: .

[0034] It should be noted that the transfer function of the electromagnetic feedback actuator in the sensor closed-loop control circuit comprises two parts: the transfer function of the voltage-to-current conversion circuit and the electromagnetic actuator function. The entire electromagnetic feedback actuator transfer function can be expressed as: .

[0035] in, m For quality that is sensitive to quality, R e It is a voltage-to-current conversion resistor.

[0036] It should be noted that in sensor closed-loop feedback control, typically... Therefore, the formula for the sensor scaling factor is: .

[0037] In modular sensor design, the quality of the sensitive mass m Coil length L and the magnetic field BThe value of the voltage-current conversion resistor is usually kept constant, so the sensor scaling factor can be adjusted by changing the value of the voltage-current conversion resistor.

[0038] In summary, since the scaling factor of a sensor is equal to the ratio of the output voltage to the measured input quantity, and the feedback gain directly determines the magnitude of this ratio, changing the value of the adjustable resistor is equivalent to changing the voltage-to-current conversion resistor, thus linearly adjusting the scaling factor.

[0039] Alternatively, the adjustable resistor can be a mechanical potentiometer, a digital potentiometer, or a resistor network consisting of a fixed resistor and a MOSFET switch. Furthermore, voltage-controlled resistors can be used to achieve continuous electronic adjustment. All these devices allow for on-site or remote adjustment of the scaling factor without altering the sensor's mechanical structure.

[0040] Furthermore, the feedback actuator module 400 includes: a voltage drive unit 500, a voltage-to-current conversion unit 600, and a feedback coil 700; the output terminal of the feedback control module 300 is connected to the input terminal of the voltage drive unit 500, the output terminal of the voltage drive unit 500 is connected to the input terminal of the voltage-to-current conversion unit 600, and the output terminal of the voltage-to-current conversion unit 600 is connected to the feedback coil 700.

[0041] It should be noted that the voltage drive unit 500 is configured to receive feedback control signals, and after amplifying or buffering the feedback control signals, provide drive voltage to the voltage-current conversion unit 600.

[0042] Understandably, the voltage drive unit 500 is configured to receive the feedback control signal and perform necessary signal conditioning on the voltage, including voltage amplification, buffer isolation, or impedance transformation, to ensure a stable voltage signal with sufficient driving capability is provided to subsequent circuits. Specifically, the feedback control signal may originate from the output of the feedback control module 300, with an amplitude range of millivolts to several volts and a high output impedance. Directly driving the subsequent load would lead to signal attenuation or distortion. The voltage drive unit 500 uses an operational amplifier to construct a non-inverting amplifier, an inverting amplifier, or a voltage follower to achieve low-distortion amplification or unity-gain buffering of the input voltage. The presence of this unit ensures that the voltage-to-current conversion unit 600 obtains a precise and low-resistance drive voltage, avoiding conversion errors caused by changes in the output impedance of the preceding stage, thereby improving the control accuracy of the feedback force.

[0043] It should be noted that the voltage-to-current conversion unit 600 is configured to convert the driving voltage into an excitation current and output it to the feedback coil 700; the feedback coil 700 is used to generate a feedback force proportional to the excitation current and act on the sensitive mass 203.

[0044] Understandably, the voltage-to-current conversion unit 600 is configured to convert the driving voltage output by the voltage drive unit 500 into a proportional excitation current and output it to the feedback coil 700. Its core function is to achieve linear voltage-to-current conversion. Through the voltage-to-current conversion unit, a definite proportional relationship is established between the current in the feedback coil and the feedback control signal, thereby making the feedback force controllable and linear.

[0045] Understandably, the feedback coil 700 receives the excitation current output from the voltage-to-current conversion unit 600 and generates an Ampere force proportional to the current in the magnetic field. This force acts on the sensitive mass, restoring it to its equilibrium position. The feedback coil is typically made of enameled copper wire wound on a frame and placed in a constant air-gap magnetic field formed by a permanent magnet. Therefore, the feedback force is unaffected by the displacement amplitude, exhibiting better linearity and a wider dynamic range; simultaneously, due to the use of current drive, the feedback force is insensitive to temperature changes, improving long-term stability.

[0046] Understandably, this design brings the following benefits: First, the separation of voltage drive and voltage-to-current conversion facilitates independent optimization of the performance of each stage. For example, adding a low-pass filter to the voltage drive unit can further suppress high-frequency noise, and using high-precision resistors in the voltage-to-current conversion unit can improve conversion linearity. Second, the feedback coil uses current drive instead of voltage drive, avoiding the influence of coil resistance changes with temperature on the feedback force, because the output current of the current source is almost unaffected by changes in load resistance. Finally, the gain adjustment point (adjustable resistor) of the entire link can be flexibly arranged in the pre-stage or post-stage, providing users with a variety of scaling factor calibration strategies. Compared to directly connecting the feedback control signal to the coil, this solution significantly improves the robustness of feedback control and the adjustable accuracy of the scaling factor, making it particularly suitable for applications requiring long-term stable operation and large ambient temperature variations.

[0047] In one feasible embodiment, the voltage-current conversion unit 600 includes at least one adjustable resistor and at least one fixed resistor; the adjustable resistor and the fixed resistor are connected in series and / or parallel between the voltage drive unit 500 and the feedback coil 700.

[0048] Understandably, the core function of this resistor network is to collectively determine the equivalent transconductance gain G of the voltage-to-current conversion unit 600. mThis is the coefficient that converts the driving voltage into the excitation current. By adjusting the value of the adjustable resistor, the equivalent resistance of the entire network can be changed, thereby changing the current flowing through the feedback coil 700, ultimately adjusting the scaling factor. The fixed resistor is used to set the basic gain range, limit the maximum current, or improve linearity. This combined design is more flexible than using a single adjustable resistor: on the one hand, a wider adjustment range and higher resolution can be obtained through series and parallel connections; on the other hand, the thermal stability of the fixed resistor is better than that of the adjustable resistor, which helps to reduce temperature drift.

[0049] Specifically, please refer to Figure 2 , Figure 2 This is a schematic diagram of a combination of adjustable resistor and fixed resistor provided in an embodiment of this application.

[0050] Figure 2 In the middle, the voltage-current conversion unit 600 includes: a first fixed resistor 601, a second fixed resistor 602 and an adjustable resistor 603; the first fixed resistor 601 and the adjustable resistor 603 are connected in parallel; the first end of the parallel connection is connected to the second end of the second fixed resistor 602; the second end of the parallel connection is connected to the feedback coil 700; the first end of the second fixed resistor 602 is connected to the output terminal of the voltage drive unit 500.

[0051] In this structure, the output voltage of the voltage drive unit 500 V d First, the resistance is added to the total resistance formed by the second fixed resistor 602 connected in series with the parallel branch. Let the equivalent resistance of the parallel branch be... R eq = ( R 601 ×R 603 ) / ( R 601 +R 603 ), then the total resistance R total =R 602 +R eq The current flowing through the feedback coil is 700. I coil = V d / R total (Ignore the coil's own DC resistance). Adjusting the resistance of adjustable resistor 603 will change... R eq Thus change I coil For example, increase R 603It will make R eq Increase, approach R 601 As the total resistance increases, the current decreases, and the feedback force weakens. To balance the same measured force, a larger feedback control signal is needed, thus increasing the scaling factor. Conversely, a smaller resistance results in a smaller current and a weaker feedback force. R 603 Then the scaling factor decreases.

[0052] The advantage of this topology is that the first fixed resistor 601 is connected in parallel with the adjustable resistor 603, which limits the range of change of the equivalent resistance when the adjustable resistor is adjusted, and will not exceed [the specified value]. R 601 To prevent damage to the coil due to excessive current caused by an accidental open circuit in the adjustable resistor, the second fixed resistor 602 limits the current and sets the base gain, ensuring that the total resistance is not zero even if the adjustable resistor is short-circuited. In practical applications, R 601 10kΩ can be selected. R 602 If we choose a 1kΩ potentiometer and select an adjustable resistor 603, then... R eq The current can be adjusted from 0 to approximately 9.09 kΩ, and the total resistance can be adjusted from 1 kΩ to 10.09 kΩ, with a current adjustment range of approximately 10 times. In addition, the first fixed resistor can be replaced with a negative temperature coefficient thermistor to achieve temperature compensation, or the second fixed resistor can be replaced with an adjustable resistor to achieve two levels of adjustment: coarse and fine.

[0053] Specifically, please refer to Figure 3 , Figure 3 This is a schematic diagram illustrating another combination of adjustable resistor and fixed resistor provided in an embodiment of this application.

[0054] Figure 3 In the voltage-to-current conversion unit 600, there are: a first fixed resistor 601 and two adjustable resistors 603; the first fixed resistor 601 and any one of the adjustable resistors 603 are connected in parallel; the first end of the parallel connection is connected to the second end of the other adjustable resistor 603; the second end of the parallel connection is connected to the feedback coil 700; and the first end of the other adjustable resistor 603 is connected to the output terminal of the voltage drive unit 500. This structure is equivalent to... Figure 2 The second fixed resistor 602 in the circuit is also replaced with an adjustable resistor, thereby realizing two independent degrees of freedom of adjustment.

[0055] Understandably, the total resistance R total =R B + ( R 601 ×R A ) / ( R 601 +R A By adjusting the adjustable resistors A (in the parallel branch) and B separately, the transconductance gain can be controlled more precisely. For example, B can be adjusted first to set the coarse adjustment range, and then A can be adjusted for fine adjustment; or a wider adjustment range can be achieved without sacrificing resolution by using a combined change in A and B. Furthermore, this design allows for coverage of a wider scaling factor range without replacing any fixed resistors, making it suitable for general-purpose test equipment that requires frequent range changes.

[0056] However, introducing two adjustable resistors simultaneously also has drawbacks: decreased thermal stability and the potential for nonlinear coupling during adjustment (changing A affects the current distribution in the branch containing B). To overcome these problems, multi-turn precision potentiometers can be used to improve adjustment accuracy, or digital potentiometers can be used in conjunction with a microcontroller to achieve automatic calibration.

[0057] It is worth noting that the adjustable resistor 603 is adjusted via a rotary motor adjustment mechanism or a digitally controlled potentiometer. The rotary motor adjustment mechanism typically consists of a stepper motor or DC servo motor paired with a reduction gear set. The motor output shaft directly drives the potentiometer shaft to rotate via a coupling or worm gear, thereby changing the resistance value. This method is suitable for industrial environments requiring remote or automatic calibration, such as in enclosed containers or high-temperature environments where manual operation is impossible. A host computer can send pulse commands to drive the motor for gradual adjustment. Its advantages include high torque, vibration resistance, and maintaining position after power failure; its disadvantages include larger size, slower response speed, and mechanical wear.

[0058] It is worth noting that fixed resistors (such as...) Figure 2 or Figure 3 The first fixed resistor 601 and the second fixed resistor 602 in the circuit should be high-precision fixed resistors. Precision fixed resistors typically refer to metal film resistors or foil resistors with a tolerance ≤ ±0.1% and a temperature coefficient ≤ ±25ppm / °C. In the voltage-current conversion unit, the fixed resistor and the adjustable resistor together determine the equivalent transconductance gain, and the absolute accuracy and stability of their resistance values ​​directly affect the initial calibration accuracy and long-term drift of the scaling factor.

[0059] It is understandable that, regardless of Figure 2 still Figure 3The core of these resistor combination methods lies in utilizing a series-parallel network of adjustable and fixed resistors to flexibly adjust the feedback gain within the voltage-to-current conversion unit, thereby altering the sensor's scaling factor. Compared to using a single adjustable resistor directly in series in the loop, the fixed resistor limits the minimum loop resistance, preventing excessive current from burning out the coil or drive circuit when the adjustable resistor is zeroed. The parallel structure makes the curve of equivalent resistance changing with the adjustable resistor smoother, avoiding the problem of excessive sensitivity in the high-resistance region when adjusting a single adjustable resistor. Simultaneously, the fixed resistor has a lower temperature coefficient, far superior to carbon film potentiometers; therefore, the overall network temperature drift is mainly dominated by the fixed resistor, improving the long-term stability of the scaling factor.

[0060] In addition, by adding a combination of multiple fixed resistors and adjustable resistors, segmented adjustment can be achieved, or different resistor networks can be switched by relays / analog switches to achieve digital automatic range switching.

[0061] Furthermore, this application implements adjustment of the scaling factor by adjusting the voltage-to-current conversion resistor. However, to ensure that the sensor can operate normally with negative feedback and achieve optimal closed-loop control performance, the control parameters in the feedback control module 300 need to be fine-tuned and adapted when necessary.

[0062] Understandably, changes in feedback gain directly affect the open-loop transfer function of the entire closed-loop control system, including its gain margin, phase margin, bandwidth, and damping ratio. Specifically, when the feedback gain increases, the open-loop gain increases accordingly, which may lead to system instability; when the feedback gain decreases, the system response speed slows down, and the steady-state error may increase. Therefore, simply adjusting the voltage-to-current conversion resistor without adaptively adjusting the control parameters of the feedback control module 300 may cause the closed-loop control performance to deviate from the optimal state, manifested as the rise time, peak time, and settling time of the step response not meeting design requirements, or the generation of resonance peaks at specific frequencies. To ensure that the sensor always operates in a stable state with excellent dynamic performance, necessary fine-tuning and adaptation of the control parameters (such as proportional coefficient, integral time constant, and derivative time constant) in the feedback control module 300 is required.

[0063] Specifically, this application provides two sensor structures. Please refer to... Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of the scale factor adjustment structure of the electromagnetic feedback metal reed capacitor accelerometer provided in the embodiments of this application; Figure 5 This is a schematic diagram of the scale factor adjustment structure of the electromagnetic feedback micromechanical capacitive accelerometer provided in an embodiment of this application.

[0064] Figure 4In this design, the sensitive probe 100 employs a spring-mass mechanical structure, including a mechanical outer frame 201, a capacitor fixed electrode 202, a sensitive mass 203, a spring 205, a permanent magnet 206, a moving electrode metal-coated film 207, and an electromagnetic feedback coil 700. The sensitive probe 100 converts the measured acceleration signal into a sensitive mass displacement signal. The moving electrode metal-coated film 207 and the fixed electrode 202 form a capacitor, converting the displacement signal into a capacitance change. The sensing module 200 converts this capacitance change into a voltage signal, which is output to the feedback control module 300 to output the accelerometer output voltage. Vout The output voltage Vout Connect the voltage drive unit 500, which drives the voltage-current conversion unit 600 to output the excitation current of the feedback electromagnetic feedback coil 700. The excitation current of the electromagnetic coil 700 and the permanent magnet 206 generate an Ampere force to drive the sensitive mass 203 back to the force balance position, forming an accelerometer closed-loop control circuit.

[0065] Figure 5 In the variable area accelerometer, the sensitive probe 100 adopts a spring-mass mechanical structure, including a mechanical upper and lower cover plate outer frame 201, a capacitor fixed electrode plate 202 coating array, a sensitive mass 203, a spring 205, a permanent magnet 206, a moving electrode plate metal coating array 207, and a coating electromagnetic feedback coil 700.

[0066] Understandably, the sensitive probe 100 converts the acceleration signal to be measured into a sensitive mass displacement signal. The array of moving electrode metal coatings 207 and the array of fixed electrode coatings 202 form an array capacitor, which converts the displacement signal into an equivalent capacitance change. The sensing module 200 converts the capacitance change into a voltage signal, which is then output to the feedback control module 300, and finally outputs the accelerometer output voltage. Vout Output voltage Vout The voltage drive unit 500 is connected, and the voltage drive unit 500 drives the voltage-current conversion unit 600 to output the excitation current of the feedback electromagnetic feedback coil 700. The excitation current of the electromagnetic feedback coil 700 and the permanent magnet 206 generate an Ampere force to drive the sensitive mass 203 back to the force balance position, forming an accelerometer closed-loop control circuit.

[0067] In addition, this application also proposes an embodiment of a multi-sensor measurement system, including: at least two electromagnetic feedback sensors with adjustable scaling factors in the first aspect; the adjustable resistance of each sensor is independently adjusted so that the scaling factors of each sensor are matched with each other.

[0068] It is understandable that mutual matching here means that, under the same input of the measured parameter (e.g., each sensor is subjected to the same acceleration or pressure at the same time), the difference in the output voltage amplitude of each sensor is less than a preset threshold (e.g., ≤0.1% of full scale output).

[0069] It should be noted that the matching process can be achieved through the following steps: First, place each sensor under the same physical excitation source (such as a vibration table, centrifuge, or pressure calibrator) and record the original output of each sensor; then, adjust the adjustable resistor of each sensor one by one according to the output deviation until all outputs converge to the same level; finally, if necessary, fine-tune the control parameters of the feedback control module 300 to maintain the consistency of the dynamic response of each sensor.

[0070] It should be noted that the multi-sensor measurement system embodiments proposed in this application can be applied to various scenarios. For example, in a triaxial orthogonal inertial measurement unit, the scale factors of the three axes are made consistent by independently adjusting the adjustable resistors of each sensor, thereby eliminating attitude calculation errors caused by proportional misalignment; in a vehicle or aircraft multi-point vibration monitoring and active vibration isolation system, the scale factors of the sensors at each mounting point are matched to ensure accurate suppression of common-mode noise in vibration synthesis and differential operations; in a dual-sensor differential tilt angle measurement device, gravity common-mode leakage is suppressed by scale factor matching to improve tilt angle resolution; and in a structural health monitoring array, the sensitivity of each array element is unified to avoid contamination of transfer function and modal analysis results by channel differences.

[0071] Understandably, by independently adjusting the adjustable resistor of each sensor, the scaling factors of each sensor can be matched with each other, thereby effectively suppressing the translational and rotational noise interference of the carrier environment in applications such as multi-sensor vector synthesis, differential operation, or array analysis, and improving measurement accuracy and system consistency.

[0072] Compared with the prior art, the beneficial effects of the multi-sensor measurement system provided in this application are the same as those of the scale factor adjustable electromagnetic feedback sensor provided in the above embodiments, and will not be repeated here.

[0073] In addition, this application also proposes an embodiment of a scaling factor adjustment method, which applies a multi-sensor measurement system of the second aspect, including: acquiring the current target scaling factor; adjusting the resistance value of the adjustable resistor of each sensor based on the target scaling factor so that the scaling factors of each sensor are matched with each other; and fusing the output signals of each sensor. This method can be widely used in differential combination measurement of sensors, such as rotational accelerometer gravity gradient meter to suppress common-mode noise.

[0074] Understandably, the target scaling factor refers to the uniform sensitivity value that the system expects to achieve, which can typically be set by the user, issued by the host computer, or automatically selected based on historical calibration data. Mutual matching means that the deviation between the actual scaling factor of each sensor and the target scaling factor is less than a preset threshold. Fusion processing refers to performing arithmetic operations (such as weighted averaging, differential averaging, and principal component analysis) on the outputs of multiple sensors to extract useful signals and reduce common-mode components. The core of this method lies in achieving scaling factor uniformity through electrical means, and then further improving the signal-to-noise ratio through signal fusion. The two work synergistically to solve the problems of scaling factor inconsistency and environmental noise interference in multi-sensor linkage.

[0075] Compared with the prior art, the beneficial effects of the scaling factor adjustment method provided in this application are the same as those of the multi-sensor measurement system provided in the above embodiments, and will not be repeated here.

[0076] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0077] Furthermore, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0078] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A scaling factor-adjustable electromagnetic feedback sensor, characterized in that, include: A sensitive probe is used to convert the measured parameter into a displacement signal of a sensitive mass; A sensing module, connected to the sensitive probe, is used to convert the displacement signal into a voltage signal; A feedback control module, connected to the sensing module, is used to receive the voltage signal and output a feedback control signal; A feedback actuator module, connected to the feedback control module, is used to receive the feedback control signal and generate a feedback force to drive the sensitive mass back to the equilibrium position; The feedback actuator module includes at least one adjustable resistor, and the feedback gain is adjusted by changing the resistance value of the adjustable resistor to change the scaling factor of the sensor.

2. The scale-adjustable electromagnetic feedback sensor as described in claim 1, characterized in that, The feedback actuator module further includes: a voltage drive unit, a voltage-to-current conversion unit, and a feedback coil; The output terminal of the feedback control module is connected to the input terminal of the voltage drive unit, the output terminal of the voltage drive unit is connected to the input terminal of the voltage-to-current conversion unit, and the output terminal of the voltage-to-current conversion unit is connected to the feedback coil. The voltage driving unit is configured to receive the feedback control signal, and after amplifying or buffering the feedback control signal, provide a driving voltage to the voltage-to-current conversion unit. The voltage-to-current conversion unit is configured to convert the driving voltage into an excitation current and output it to the feedback coil; The feedback coil is used to generate a feedback force proportional to the excitation current and acts on the sensitive mass.

3. The scale-factor-adjustable electromagnetic feedback sensor as described in claim 2, characterized in that, The voltage-current conversion unit includes: at least one adjustable resistor and at least one fixed resistor; The adjustable resistor and the fixed resistor are connected in series and / or in parallel between the voltage drive unit and the feedback coil.

4. The scale-adjustable electromagnetic feedback sensor as described in claim 3, characterized in that, The voltage-current conversion unit includes: a first fixed resistor, a second fixed resistor, and an adjustable resistor; The first fixed resistor is connected in parallel with the adjustable resistor; the first end of the parallel connection is connected to the second end of the second fixed resistor; the second end of the parallel connection is connected to the feedback coil; and the first end of the second fixed resistor is connected to the output terminal of the voltage drive unit.

5. The scale-factor-adjustable electromagnetic feedback sensor as described in claim 3, characterized in that, The voltage-current conversion unit includes: a first fixed resistor and two adjustable resistors; The first fixed resistor and any adjustable resistor are connected in parallel; the first end of the parallel connection is connected to the second end of another adjustable resistor; the second end of the parallel connection is connected to the feedback coil; and the first end of the other adjustable resistor is connected to the output terminal of the voltage drive unit.

6. The scale-adjustable electromagnetic feedback sensor as described in any one of claims 1 to 5, characterized in that, Sensor scaling factor K The expression is: ； in, R e This is a voltage-to-current conversion resistor; m For quality that is sensitive to quality; L The length of the electromagnetic coil; B The magnetic field in which the sensitive mass is located.

7. The scale-factor-adjustable electromagnetic feedback sensor as described in any one of claims 1 to 5, characterized in that, The adjustable resistor is adjusted by means of a rotary motor adjustment mechanism or a digital control potentiometer.

8. The scale-factor-adjustable electromagnetic feedback sensor as described in claim 1, characterized in that, The sensitive probe is a variable-gap capacitive accelerometer sensitive probe or a variable-area capacitive accelerometer sensitive probe.

9. A multi-sensor measurement system, characterized in that, include: At least two scale factor-adjustable electromagnetic feedback sensors as described in any one of claims 1 to 8; The adjustable resistors of each sensor are adjusted independently to match the scaling factors of each sensor.

10. A scaling factor adjustment method, characterized in that, The multi-sensor measurement system as described in claim 9 includes: acquiring the current target scaling factor; adjusting the resistance value of the adjustable resistor of each sensor based on the target scaling factor to match the scaling factors of each sensor; and fusing the output signals of each sensor to suppress common-mode noise.

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