CN112180119A - Quartz flexible accelerometer, servo circuit and acceleration signal conversion method - Google Patents
Quartz flexible accelerometer, servo circuit and acceleration signal conversion method Download PDFInfo
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- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
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- G—PHYSICS
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- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
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- G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
- G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
- G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
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Abstract
The invention discloses a quartz flexible accelerometer, a servo circuit and an acceleration signal conversion method.A differential capacitance converter is connected with a differential capacitance signal in a quartz gauge head, and the differential capacitance converter signal is connected with a signal of a current integrator; the signal output end of the current integrator is simultaneously connected with the signal input end of the transconductance/compensation amplifier and the signal of the resistance-capacitance feedback network; one end of the transconductance/compensation amplifier is connected with the torquer of the quartz gauge head, and the other end of the transconductance/compensation amplifier is connected with the resistance-capacitance feedback network; the quartz gauge head torquer is connected with one end of the precision sampling resistor, and the other end of the precision sampling resistor is connected with an analog signal ground wire; the torquer is connected with the Butterworth low-pass filter, the Butterworth low-pass filter is connected with the A/D converter, and a digital signal of the A/D converter is connected with the servo circuit. The speed of signal processing is improved, the power consumption is reduced, the size can be reduced, and the internal space of the whole navigation system is expanded.
Description
Technical Field
The invention belongs to the field of accelerometers, and relates to a quartz flexible accelerometer, a servo circuit and an acceleration signal conversion method.
Background
The quartz flexible accelerometer has the characteristics of simple structure, high precision, good stability, strong anti-interference capability and the like, has become a mainstream product in a mechanical pendulum accelerometer, is an indispensable key device in the current inertial navigation and guidance system, is widely applied to the national strategic fields of aerospace flight control, remote strategic tactical weapon guidance, railway track inspection vehicle body vibration measurement, petroleum, mineral deposit and other drilling inclinometer systems, and has great social and military benefits.
In an inertial navigation system and other acceleration measurement systems, an analog current signal output by a quartz flexible accelerometer needs to be converted into a digital signal so as to be processed by a digital system such as a later-stage FPGA or a DSP. Common analog/digital conversion schemes are mainly a/D converters, current/frequency converters and voltage/frequency converters. The current/frequency converter has strong anti-interference capability, high conversion precision and good temperature characteristic, but is often used in a large-scale inertial navigation platform system with low requirements on volume and power consumption due to the huge conversion system, high power consumption and complex circuit. Voltage/frequency converters typically undergo a current/voltage conversion, thereby losing overall accuracy. Due to the rapid development of microelectronic design and process level in recent years, the conversion precision and the temperature coefficient of the A/D converter have been developed to a very high level, the A/D converter is widely applied to various data acquisition systems, the integration level is higher, a single chip can complete multi-path data acquisition, and the analog-to-digital conversion cost of the system can be reduced; the power consumption is lower, and the power consumption of the A/D converter is always in a mu W level in a non-working state; the slew rate is higher, and the slew rate of the A/D converter can reach dozens of times of that of the current/frequency converter. Therefore, the a/D converter has been widely used in the field of commercial navigation systems and military inertial navigation, which requires high volume power consumption.
When an A/D converter is used for analog-digital conversion in the conventional inertial navigation system and other similar acceleration measurement systems, current signals output by a quartz flexible accelerometer are connected to a special data acquisition system through a patch cord, and the current signals are processed in a subsequent digital system such as a Field Programmable Gate Array (FPGA) or a Digital Signal Processor (DSP) after data conversion, so that an independent data acquisition board card is required. On one hand, the method ensures that analog signals output by the quartz flexible accelerometer need to pass through a long transmission path and are easily interfered by external electromagnetic interference, thereby reducing the data conversion precision; on the other hand, the data acquisition board card occupies the internal space of the navigation system, so that the whole inertial navigation system becomes more huge.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a quartz flexible accelerometer, a servo circuit and an acceleration signal conversion method, which can improve the signal processing rate, reduce the power consumption, reduce the volume and expand the internal space of the whole navigation system.
In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:
a servo circuit of a quartz flexible accelerometer comprises a quartz gauge head, a differential capacitance converter, a current integrator, a transconductance/compensation amplifier, a resistance-capacitance feedback network, a precise sampling resistor, a Butterworth low-pass filter and an A/D converter;
the signal input end of the differential capacitance converter is connected with the signal output end of a differential capacitance in the quartz gauge head, and the signal output end of the differential capacitance converter is connected with the signal input end of the current integrator; the signal output end of the current integrator is simultaneously connected with the signal input end of the transconductance/compensation amplifier and the signal output end of the resistance-capacitance feedback network; one signal output end of the transconductance/compensation amplifier is connected with the input end of a torquer of the quartz gauge head, and the other signal output end of the transconductance/compensation amplifier is connected with the signal input end of the resistance-capacitance feedback network; the signal output end of the quartz gauge head torquer is connected with one end of a precision sampling resistor, and the other end of the precision sampling resistor is connected with an analog signal ground wire; the signal output end of the torquer is connected with the signal input end of the Butterworth low-pass filter, the signal output end of the Butterworth low-pass filter is connected with the analog signal input end of the A/D converter, and the digital signal output end of the A/D converter is connected with the leading-out end of the servo circuit.
Preferably, the butterworth low-pass filter is a4 th order butterworth low-pass filter.
Further, the 4 th-order butterworth low-pass filter comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, an operational amplifier U1 and an operational amplifier U2;
the signal output end of a torquer in the quartz gauge head is connected with one end of a resistor R1 at the signal input end of the 4-order Butterworth low-pass filter, the other end of the resistor R1 is respectively connected with one end of a resistor R2, a resistor R3 and a capacitor C1, and the other end of the capacitor C1 is grounded; the other end of the resistor R2 is respectively connected with the inverting input end of the operational amplifier U1 and one end of the capacitor C2; the other end of the resistor R3 is connected with the output end of the operational amplifier U1; the other end of the capacitor C2 is connected with the output end of the operational amplifier U1; the non-inverting input end of the operational amplifier U1 is grounded; one end of the resistor R4 is connected with the output end of the operational amplifier U1, the other end of the resistor R4 is connected with one end of the resistor R5, one end of the resistor R6 and one end of the capacitor C3, and the other end of the capacitor C3 is grounded; the other end of the resistor R5 is respectively connected with the inverting input end of the operational amplifier U2 and one end of the capacitor C4; the other end of the resistor R6 is connected with the output end of the operational amplifier U2; the other end of the capacitor C4 is connected with the output end of the operational amplifier U2; the non-inverting input end of the operational amplifier U2 is grounded; the output end of the operational amplifier U2 is connected with the analog signal input end of the A/D converter.
Preferably, the differential capacitor converter is an LZF15 type chip, the transconductance/compensation amplifier is an LC5226 type chip, and the A/D converter is an ADS1281 type chip.
When the external world has acceleration along the sensitive axis direction of the quartz gauge head, a movable pendulous reed of the quartz gauge head displaces under the action of external inertia moment to generate differential capacitance change, a differential capacitance detector converts the differential capacitance change into current, the current is integrated by a current integrator to form voltage, the voltage is converted and amplified into current iout by a transconductance/compensation amplifier, a sampling resistor converts the current iout into a voltage signal V1, the voltage signal V1 is filtered and shaped by a Butterworth low-pass filter, the voltage signal V1 enters an A/D converter to be subjected to analog-to-digital conversion, and the converted digital signal is output to the outside through a leading-out end of a servo circuit to complete acceleration measurement and digital conversion.
Preferably, the current iout passes through a torquer of the quartz gauge head to generate a rebalancing moment to balance the inertia moment caused by the acceleration and drive the movable pendulum piece in the internal differential capacitance sensor of the quartz gauge head to return to the central balance position.
Preferably, the transconductance/compensation amplifier performs equal-proportion sampling on the current iout, inputs the sampled current iout into the resistance-capacitance feedback network, and generates a proportional-integral-derivative feedback control quantity to perform closed-loop control on the transconductance/compensation amplifier.
A quartz flexible accelerometer based on any one of the circuits comprises a quartz gauge outfit, a first PCB, a second PCB and a rear cover which are coaxially and sequentially arranged;
the first PCB is provided with a differential capacitance detector, a current integrator, a transconductance/compensation amplifier, a resistance-capacitance feedback network, a precise sampling resistor and a Butterworth low-pass filter; the second PCB board is provided with an A/D converter and a corresponding peripheral circuit thereof, the first PCB board and the second PCB board are connected by metal pins, one side of the rear cover, which is far away from the quartz gauge outfit, is provided with a connector, and the connector is connected with the second PCB board.
Preferably, a cylindrical PPS resin is nested on the metal pin between the first PCB and the second PCB.
Preferably, the connector is a J63A type connector.
Compared with the prior art, the invention has the following beneficial effects:
the circuit of the invention overcomes the defects of complex circuit and large volume of the current/frequency and voltage/frequency converter by adopting the integrated A/D conversion chip. The single chip can complete multi-path data acquisition, the signal processing rate can be improved, the power consumption is reduced, the size can be reduced, and the internal space of the whole navigation system is expanded.
The acceleration signal conversion method has the advantages of high precision, low power consumption, high integration degree, high conversion speed and the like. Compared with other acceleration signal conversion methods, the method provided by the invention adopts the integrated A/D conversion chip to realize the conversion of the analog/digital signals, and overcomes the defects of complex circuit and large volume of current/frequency and voltage/frequency converters. The single chip can complete multi-path data acquisition, the signal processing rate is improved, the power consumption is reduced, the size can be reduced, the internal space of the whole navigation system is expanded, and the method is a non-second choice of acceleration signal processing technologies in the fields of commercial inertia measurement and military navigation.
The quartz flexible accelerometer realizes digital conversion of output signals on the basis of not changing the original size. Compared with the traditional quartz flexible accelerometer, the accelerometer has higher integration and smaller power consumption. The provided digital output signal can be directly supplied to a post-stage digital system for processing, a separate data acquisition card is not required to be provided, the internal space of the navigation system is effectively expanded, the interference and loss in the long-distance transmission process of the signal are reduced, and the precision of the navigation system is improved.
Drawings
FIG. 1 is a schematic block diagram of a servo circuit of the present invention;
FIG. 2 is an electrical schematic of a4 th order Butterworth low pass filter of the present invention;
FIG. 3 is an exploded view of a first perspective of the quartz flexure accelerometer of the present invention;
fig. 4 is an exploded view of a quartz flexure accelerometer of the present invention from a second perspective.
Wherein: 1-quartz watch head; 2-a first PCB board; 3-metal pin insertion; 4-a second PCB board; 5-rear cover; 6-connector.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings:
the digital output type quartz flexible accelerometer servo circuit disclosed by the invention comprises a differential capacitance converter, a current integrator, a transconductance/compensation amplifier, a resistance-capacitance feedback network, a precise sampling resistor, a Butterworth low-pass filter, an A/D converter, a precise voltage reference, a secondary power distribution source and other peripheral resistance-capacitance elements as shown in figure 1. The signal input end of the differential capacitance converter is connected with the signal output end of the inner differential capacitance converter in the quartz gauge head 1, the signal output end of the differential capacitance converter is connected with the signal input end of the current integrator, and the signal output end of the current integrator is simultaneously connected with the signal input end of the transconductance/compensation amplifier and the signal output end of the resistance-capacitance feedback network; one signal output end of the transconductance/compensation amplifier is connected with the input end of the torquer of the quartz gauge head 1, the other signal output end of the transconductance/compensation amplifier is connected with the signal input end of the resistance-capacitance feedback network, the signal output end of the torquer of the quartz gauge head 1 is connected with one end of the precise sampling resistor, and the other end of the precise sampling resistor is connected with the analog signal ground wire. Meanwhile, the signal output end of the torquer is connected with the signal input end of the Butterworth low-pass filter, the signal output end of the Butterworth low-pass filter is connected with the analog signal input end of the A/D converter, and the digital signal output end of the A/D converter is connected with the leading-out end of the shell of the servo circuit and serves as the signal output end of the quartz flexible accelerometer.
As shown in fig. 2, the butterworth low-pass filter adopts a 4-order butterworth low-pass filter, a signal output end of a torquer in the quartz gauge head 1 is connected with one end of a resistor R1 at a signal input end of the 4-order butterworth low-pass filter, and the other end of R1 is respectively connected with one end of a resistor R2, a resistor R3 and a capacitor C1; the other end of the resistor R2 is respectively connected with the inverting input end of the operational amplifier U1 and one end of the capacitor C2; the other end of the resistor R3 is connected with the output end of the operational amplifier U1; the other end of the capacitor C1 is grounded; the other end of the capacitor C2 is connected with the output end of the operational amplifier U1; the non-inverting input of operational amplifier U1 is grounded. One end of the resistor R4 is connected with the output end of the operational amplifier U1, and the other end is connected with one ends of the resistor R5, the resistor R6 and the capacitor C3; the other end of the resistor R5 is respectively connected with the inverting input end of the operational amplifier U2 and one end of the capacitor C4; the other end of the resistor R6 is connected with the output end of the operational amplifier U2; the other end of the capacitor C3 is grounded; the other end of the capacitor C4 is connected with the output end of the operational amplifier U2; the non-inverting input of operational amplifier U2 is grounded. The output end of the operational amplifier U2 is connected with the analog signal input end of the A/D converter, and the digital signal output end of the A/D converter is connected with the leading-out end of the servo circuit shell and is used as the signal output end of the quartz flexible accelerometer.
The differential capacitance converter adopts an LZF15 type chip, the transconductance/compensation amplifier adopts an LC5226 type chip, the 4-order Butterworth low-pass filter consists of an ADA4528 precision operational amplifier and a peripheral resistance-capacitance element, the A/D converter adopts an ADS1281 type chip, the precision voltage reference adopts an MAX6325 type chip, and the secondary power distribution source adopts an ADP7102 type chip and an ADP7182 type chip.
The digital output type quartz flexible accelerometer servo circuit is shown in a schematic block diagram in FIG. 1. The digital output type quartz flexible accelerometer servo circuit is combined with a special quartz gauge head 1 to complete the quartz flexible accelerometer capable of directly outputting digital quantity. The quartz gauge outfit 1 consists of a differential capacitance sensor, a torquer, a permanent magnet, a quartz gauge outfit 1 shell and other parts. When the external world does not have acceleration, the movable swinging sheet in the internal differential capacitance sensor of the quartz gauge head 1 is positioned at the central position, and the variable quantity of the differential capacitance is zero; when the outside has acceleration a along the sensitive axis direction of the quartz gauge outfit 1inWhen the current is used, the movable swinging piece is displaced under the action of external inertia moment to generate differential capacitance change, a differential capacitance detector in the servo circuit converts the capacitance change into current, the current is integrated by a current integrator to form voltage, and the voltage is converted and amplified into current i by a transconductance/compensation amplifieroutCurrent ioutPassing through the torquer of the quartz gauge head 1, generating a rebalancing torque to balance the acceleration ainThe resulting moment of inertia drives the movable pendulum in the internal differential capacitance sensor of the quartz gauge head 1 back to the center equilibrium position. At the same time, the transconductance/compensation amplifier pair current ioutAnd carrying out equal proportion sampling, inputting the equal proportion sampling into a pi-type resistance-capacitance feedback network, generating a Proportional Integral Derivative (PID) feedback control quantity to carry out closed-loop control on the transconductance/compensation amplifier so as to adjust the dynamic parameters of the system and enable the quartz flexible accelerometer to work in a stable state. Current ioutIs proportional to the input acceleration, the polarity depending on the direction of the input accelerometer.
Current ioutPassing through a torquer and then a precision sampling resistor RinTo analog ground, the precise sampling resistor Rin value and acceleration design detection range, quartz gauge head 1 scale factor and input voltage range of the post A/D converterAnd (4) correlating. If the designed detection range of the acceleration is +/-Ag, the scale factor of the quartz gauge head 1 is B mA/g, and the input voltage range of the A/D converter is +/-C V, then the following steps are carried out:
the sampling resistor converts the current signal into a voltage signal V1, and the voltage signal V1 filters and shapes the signal through a 4-order butterworth low-pass filter, wherein the 4-order butterworth low-pass filter is formed by cascading two 2-order active butterworth low-pass filters, and the circuit structure diagram is shown in fig. 2. The cut-off frequency of the filter can be changed by adjusting the value of a resistance-capacitance element in the filter so as to meet the index requirements of the system on the response time of the accelerometer and the bandwidth of the system; the signal then enters an a/D converter for analog-to-digital conversion. And finally, outputting the converted digital signals to the outside through a leading-out end of the shell of the servo circuit to finish acceleration measurement and digital conversion.
The servo circuit is manufactured by adopting a surface mounting process. The circuit principle is divided into two parts: the A/D converter and its corresponding peripheral circuit; the device comprises a differential capacitance detector, a current integrator, a transconductance compensation amplifier, a resistance-capacitance feedback network, a precision sampling resistor and a4 th-order Butterworth low-pass filter. Electronic components of the two parts are welded on the two circular flexible PCBs by adopting a reflow soldering process, and a differential capacitance detector, a current integrator, a transconductance/compensation amplifier, a resistance-capacitance feedback network, a precise sampling resistor and a Butterworth low-pass filter are arranged on the first PCB 2; the second PCB 4 is provided with an A/D converter and a corresponding peripheral circuit thereof; the outer diameters of the two PCBs are phi 24.0mm, the thicknesses of the two PCBs are 2.0mm, two phi 2.0mm circular through holes are formed in the positions of coordinates (6.1mm, -5.3mm) and (-6.1mm, -5.3mm) respectively by taking the circle center as a coordinate origin, and 12 phi 0.8mm circular through hole pads are uniformly distributed on the two PCBs at a distance of 30 degrees and with the radius of 10.5mm from the circle center. The length of a metal pin 3 used for circuit assembly is 6.0mm, the diameter is phi 0.70mm, PPS resin is coated in the middle of the pin, and the coating thickness is 1.15 mm. The servo circuit metal shell is made of 304# stainless steel, the shape is circular, the outer diameter is phi 25.4mm, the center of the shell is the origin of coordinates, the coordinates (6.1mm, -5.3mm) and (-6.1mm, -5.3mm) are respectively provided with two circular step-type through holes, the aperture is phi 6.6mm, two circular 304# stainless steel press covers are used for matching the shell, the outer diameter is phi 6.6mm, and the leading-out end of the shell is a 15-wire standard J63A type connector. The circuit assembling steps are as follows: after the PCB welded with the electronic component is subjected to plasma cleaning, a second PCB 4 is bonded to the inner cavity of the metal shell by using insulating glue, and a through hole type bonding pad of the second PCB 4 is connected with a lead post of the inner cavity of the shell by manual welding; manually welding 12 metal pins 3 on the metalized through hole bonding pad on the outer side of the second PCB 4; the first PCB 2 is manually welded and welded on the metal contact pin 3, the metal contact pin 3 completes the electrical connection between the second PCB 4 and the first PCB 2, and meanwhile the PPS resin coated by the contact pin provides mechanical support for the first PCB 2. The connection relation of the above components can enable the servo circuit to form a complete functional module, after the quartz gauge outfit 1 is in butt joint and sealed assembly with the servo circuit, five I/O interfaces of the differential capacitor upper polar plate, the differential capacitor lower polar plate, the ground, the torquer high end and the torquer low end of the quartz gauge outfit 1 can be led out through circular through holes of two PCB plates in the servo circuit and connected to corresponding metallized bonding pads on the back of the second PCB plate 4 through manual welding, and the electrical connection of the quartz gauge outfit 1 and the servo circuit is completed. And finally, using two 304# stainless steel glands to seal the stepped through hole of the servo circuit shell, and finishing the integral sealing of the quartz flexible accelerometer. The servo circuit assembly is schematically shown in FIG. 3.
According to the invention, by adding a 32-bit high-precision A/D conversion unit in a servo circuit of the traditional quartz flexible accelerometer, the servo circuit can directly output digital quantity which is directly read by a digital processing unit such as a rear-stage FPGA or a DSP. The whole size of the circuit is reduced by a longitudinal integration method of electronic components, the whole size of the assembled circuit module is smaller than phi 25.4mm multiplied by 10mm, the quartz flexible accelerometer assembled with the quartz gauge head 1 is the same as the quartz flexible accelerometer of the traditional current output, and the whole size of the inertial navigation system can be greatly reduced. The circuit shell and the gland are made of 304# stainless steel, so that a user can adopt a laser welding process when the quartz gauge outfit 1 and the servo circuit are sealed, and the overall sealing performance and appearance quality of the quartz flexible accelerometer can be improved. The leading-out end of the servo circuit shell is a J63A type connector, and when the connector is used by a user, the connector can be directly matched with a connecting wire of the matched connector 6, so that the assembly is more convenient and reliable. The invention can be generally applied to an inertial navigation system and an acceleration measurement system of which the post-stage system needs digital quantity, and has strong universality.
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.
Claims (10)
1. A servo circuit of a quartz flexible accelerometer is characterized by comprising a quartz gauge head (1), a differential capacitance converter, a current integrator, a transconductance/compensation amplifier, a resistance-capacitance feedback network, a precise sampling resistor, a Butterworth low-pass filter and an A/D converter;
the signal input end of the differential capacitance converter is connected with the signal output end of a differential capacitance in the quartz gauge head (1), and the signal output end of the differential capacitance converter is connected with the signal input end of the current integrator; the signal output end of the current integrator is simultaneously connected with the signal input end of the transconductance/compensation amplifier and the signal output end of the resistance-capacitance feedback network; one signal output end of the transconductance/compensation amplifier is connected with the input end of a torquer of the quartz gauge head (1), and the other signal output end of the transconductance/compensation amplifier is connected with the signal input end of the resistance-capacitance feedback network; the signal output end of a torquer of the quartz gauge head (1) is connected with one end of a precision sampling resistor, and the other end of the precision sampling resistor is connected with an analog signal ground wire; the signal output end of the torquer is connected with the signal input end of the Butterworth low-pass filter, the signal output end of the Butterworth low-pass filter is connected with the analog signal input end of the A/D converter, and the digital signal output end of the A/D converter is connected with the leading-out end of the servo circuit.
2. The quartz flexible accelerometer servo circuit of claim 1, wherein the butterworth low pass filter is a4 th order butterworth low pass filter.
3. The quartz flexure accelerometer servo circuit of claim 2, wherein the 4 th order butterworth low pass filter comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, an operational amplifier U1, and an operational amplifier U2;
the signal output end of a torquer in the quartz gauge head (1) is connected with one end of a resistor R1 at the signal input end of a 4-order Butterworth low-pass filter, the other end of the R1 is respectively connected with one end of a resistor R2, a resistor R3 and a capacitor C1, and the other end of the capacitor C1 is grounded; the other end of the resistor R2 is respectively connected with the inverting input end of the operational amplifier U1 and one end of the capacitor C2; the other end of the resistor R3 is connected with the output end of the operational amplifier U1; the other end of the capacitor C2 is connected with the output end of the operational amplifier U1; the non-inverting input end of the operational amplifier U1 is grounded; one end of the resistor R4 is connected with the output end of the operational amplifier U1, the other end of the resistor R4 is connected with one end of the resistor R5, one end of the resistor R6 and one end of the capacitor C3, and the other end of the capacitor C3 is grounded; the other end of the resistor R5 is respectively connected with the inverting input end of the operational amplifier U2 and one end of the capacitor C4; the other end of the resistor R6 is connected with the output end of the operational amplifier U2; the other end of the capacitor C4 is connected with the output end of the operational amplifier U2; the non-inverting input end of the operational amplifier U2 is grounded; the output end of the operational amplifier U2 is connected with the analog signal input end of the A/D converter.
4. The quartz flexure accelerometer servo circuit of claim 1, wherein the differential capacitance converter is an LZF15 type chip, the transconductance/compensation amplifier is an LC5226 type chip, and the a/D converter is an ADS1281 type chip.
5. An acceleration signal conversion method based on the circuit of any one of claims 1-4, characterized in that when the external acceleration exists along the sensitive axis direction of the quartz gauge head (1), the movable pendulous reed of the quartz gauge head (1) is displaced under the action of the external inertia moment to generate the differential capacitance change and differenceThe moving capacitor detector converts the differential capacitance variation into current, integrates the current into voltage through a current integrator, and then converts and amplifies the voltage into current i through a transconductance/compensation amplifieroutSampling resistance will current ioutThe voltage signal V1 is converted into a voltage signal V1, the voltage signal V1 is subjected to filtering shaping through a Butterworth low-pass filter, the voltage signal V1 enters an A/D converter for analog-to-digital conversion, and the converted digital signal is output outwards through a leading-out end of a servo circuit to complete acceleration measurement and digital conversion.
6. The acceleration signal conversion method of claim 5, characterized in that the current ioutThe moment device of the quartz gauge head (1) generates rebalance moment to balance the inertia moment caused by acceleration and drive the movable swinging sheet in the internal differential capacitance sensor of the quartz gauge head (1) to return to the central balance position.
7. The acceleration signal conversion method of claim 5, wherein the transconductance/compensation amplifier pair current ioutAnd carrying out equal proportion sampling, inputting the equal proportion sampling into a resistance-capacitance feedback network, and generating a proportional-integral-derivative feedback control quantity to carry out closed-loop control on the transconductance/compensation amplifier.
8. A quartz flexible accelerometer based on the circuit of any one of claims 1-4, characterized by comprising a quartz gauge head (1), a first PCB (2), a second PCB (4) and a back cover (5) which are coaxially arranged in sequence;
the first PCB (2) is provided with a differential capacitance detector, a current integrator, a transconductance/compensation amplifier, a resistance-capacitance feedback network, a precise sampling resistor and a Butterworth low-pass filter; an A/D converter and a corresponding peripheral circuit thereof are arranged on the second PCB (4), the first PCB (2) and the second PCB (4) are connected by a metal pin (3), one side of the rear cover (5) far away from the quartz gauge outfit (1) is provided with a connector (6), and the connector (6) is connected with the second PCB (4).
9. The quartz flexure accelerometer of claim 8, wherein a cylindrical PPS resin is nested on the metal pin (3) between the first PCB (2) and the second PCB (4).
10. The quartz flexure accelerometer of claim 8, wherein the connector (6) is a J63A type connector.
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| CN112858722A (en) * | 2021-01-08 | 2021-05-28 | 中国船舶重工集团公司第七0七研究所 | Saturation fault screening device of flexible accelerometer |
| CN113624993A (en) * | 2021-08-04 | 2021-11-09 | 西安微电子技术研究所 | Acceleration signal conversion method, servo circuit and quartz flexible accelerometer |
| CN113984047A (en) * | 2021-10-29 | 2022-01-28 | 西安微电子技术研究所 | I/F conversion circuit scale factor positive and negative symmetry adjusting method |
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| CN209656731U (en) * | 2019-04-23 | 2019-11-19 | 青岛航天半导体研究所有限公司 | A kind of quartz flexible accelerometer numeral output servo circuit |
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| CN113624993A (en) * | 2021-08-04 | 2021-11-09 | 西安微电子技术研究所 | Acceleration signal conversion method, servo circuit and quartz flexible accelerometer |
| CN113984047A (en) * | 2021-10-29 | 2022-01-28 | 西安微电子技术研究所 | I/F conversion circuit scale factor positive and negative symmetry adjusting method |
| CN113984047B (en) * | 2021-10-29 | 2023-05-30 | 西安微电子技术研究所 | Method for adjusting positive and negative symmetry of scale factors of I/F conversion circuit |
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