CN116125099B - MEMS closed-loop capacitive accelerometer high linearity control method and system - Google Patents
MEMS closed-loop capacitive accelerometer high linearity control method and system Download PDFInfo
- Publication number
- CN116125099B CN116125099B CN202310046653.2A CN202310046653A CN116125099B CN 116125099 B CN116125099 B CN 116125099B CN 202310046653 A CN202310046653 A CN 202310046653A CN 116125099 B CN116125099 B CN 116125099B
- Authority
- CN
- China
- Prior art keywords
- closed
- voltage
- loop
- module
- digital
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 55
- 230000001133 acceleration Effects 0.000 claims abstract description 62
- 238000005259 measurement Methods 0.000 claims abstract description 26
- 238000012545 processing Methods 0.000 claims description 59
- 238000006243 chemical reaction Methods 0.000 claims description 45
- 230000008859 change Effects 0.000 claims description 34
- 239000003381 stabilizer Substances 0.000 claims description 22
- 238000004891 communication Methods 0.000 claims description 16
- 238000004364 calculation method Methods 0.000 claims description 9
- 101100015484 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) GPA1 gene Proteins 0.000 claims description 8
- 238000012360 testing method Methods 0.000 claims description 7
- 101100067427 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) FUS3 gene Proteins 0.000 claims description 6
- 101000872084 Danio rerio Delta-like protein B Proteins 0.000 claims description 5
- 230000009471 action Effects 0.000 abstract description 15
- 238000001514 detection method Methods 0.000 description 16
- 238000006073 displacement reaction Methods 0.000 description 9
- 230000001105 regulatory effect Effects 0.000 description 8
- 239000003990 capacitor Substances 0.000 description 7
- 230000008569 process Effects 0.000 description 6
- HEZMWWAKWCSUCB-PHDIDXHHSA-N (3R,4R)-3,4-dihydroxycyclohexa-1,5-diene-1-carboxylic acid Chemical compound O[C@@H]1C=CC(C(O)=O)=C[C@H]1O HEZMWWAKWCSUCB-PHDIDXHHSA-N 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 230000008054 signal transmission Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- 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
- G01P15/125—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 by capacitive pick-up
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Pressure Sensors (AREA)
Abstract
The invention relates to the field of MEMS inertial devices, in particular to an MEMS closed-loop electric deviceHigh linearity control method and system for capacitive accelerometer, under the condition of no extra non-compensation, calculating upper plate voltage U applied to upper plate by calculating closed loop control quantity T And a lower plate voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the The electrostatic force generated by the applied voltage counteracts the inertia force to which the mass block is sensitive under the action of acceleration, and the acceleration measurement value is calculated according to the closed-loop control quantity, so that the linearity of the closed-loop capacitive accelerometer is improved while the operation quantity is reduced, and the performance of the closed-loop capacitive accelerometer is further improved.
Description
Technical Field
The invention relates to the field of MEMS inertial devices, in particular to a high linearity control method and system of an MEMS closed-loop capacitive accelerometer.
Background
The MEMS capacitive accelerometer is one of typical applications of MEMS technology in the field of inertial devices, and is a device which applies MEMS micro-manufacturing technology and detection technology to acceleration detection, and has the advantages of low cost, small volume and the like, so that the MEMS capacitive accelerometer is widely applied to consumer electronic equipment represented by automobiles and smart phones after nineties in the twentieth century, and plays an important role in the fields of industrial production, aerospace and the like.
The MEMS closed-loop variable-spacing differential capacitive accelerometer is a high-performance product of the MEMS capacitive accelerometer, and solves the problems of high nonlinearity, incapability of combining sensitivity and measuring range and the like in an open-loop structure by closed-loop control, so that the performance of the MEMS capacitive accelerometer is promoted to tactical level in one step. However, in the process of introducing closed-loop control, the closed-loop control method suitable for theoretical conditions can introduce new nonlinear quantity in practical application due to the processing error of the MEMS structure and the asymmetry of the detection circuit. The invention of China patent publication No. CN105008935A discloses a sensor with an electrostatic pendulum accelerometer and a method for controlling the sensor, wherein the sensor with a sandwich structure is characterized in that the accelerometer is subjected to closed-loop control by applying static feedback voltage to an upper capacitance plate or a lower capacitance plate to obtain electrostatic force counteracted by inertia force in positive and negative directions, and the closed-loop control can generate non-uniform sensitivity of positive and negative acceleration detection due to asymmetry of the upper capacitance plate, the lower capacitance plate and detection, so that nonlinear items are generated; the Chinese patent with publication number CN108344881A discloses a closed-loop micro-accelerometer sensitive structure, wherein the closed-loop control method of the accelerometer with the sandwich sensitive structure is that the voltage of an intermediate electrode is fixed, voltages with the same magnitude and opposite signs are applied to an upper electrode and a lower electrode, and the closed-loop control can directly generate a nonlinear item due to the asymmetry of upper and lower capacitor plates and detection.
Therefore, a new closed-loop control method is needed to improve the linearity of the MEMS capacitive accelerometer, and thus the accelerometer performance.
Disclosure of Invention
Aiming at the problem of insufficient linearity improvement of the MEMS capacitive accelerometer by the existing closing control method, the invention provides a high linearity control method and a high linearity control system of the MEMS closed-loop capacitive accelerometer, which calculate the voltage U applied to an upper polar plate by calculating the closed-loop control quantity under the condition of not carrying out additional nonlinear compensation T And a voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the The inertial force generated by the mass block under the action of acceleration is eliminated through the electrostatic force generated by the applied voltage, the acceleration measurement value is calculated, the operation quantity is reduced, the linearity of the closed-loop capacitive accelerometer is improved, and the performance of the closed-loop capacitive accelerometer is further improved.
The invention has the following specific implementation contents:
the MEMS closed-loop capacitive accelerometer high linearity control method is used for eliminating the sensitive inertial force of the closed-loop capacitive accelerometer under the action of the inertial force; the method comprises the following steps:
step 1: generating a carrier signal, and modulating the carrier signal and an acceleration signal input into a closed-loop capacitive accelerometer into a capacitance change signal;
Step 2: demodulating the capacitance change signal into a differential analog voltage signal and converting the differential analog voltage signal into a differential digital voltage signal;
step 3: generating a closed-loop control amount required for closed-loop control according to the differential digital voltage signal, and calculating an upper plate applied to the upper plate according to the closed-loop control amountVoltage U T And a lower plate voltage U applied to the lower plate B ；
Step 4: according to the upper plate voltage U applied to the upper plate T And the electrostatic force generated by the lower plate voltage UB applied to the lower plate eliminates the inertial force to which the mass block of the closed-loop capacitive accelerometer is sensitive under acceleration, and calculates an acceleration measurement value according to the closed-loop control quantity.
In order to better implement the present invention, further, the specific operation of step 4 is as follows: calculating an upper plate voltage U applied to the upper plate according to the closed-loop control quantity and in combination with closed-loop capacitive accelerometer parameters T And a lower plate voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the The closed-loop capacitive accelerometer parameter is used to indicate a maximum range obtained by the closed-loop capacitive accelerometer.
To better implement the invention, further, the calculation of the upper plate voltage U applied to the upper plate T The specific operation of (a) is as follows:
calculating a bottom plate voltage U applied to the bottom plate B The specific operation of (a) is as follows:
wherein Δb is the closed-loop control quantity, and B is the closed-loop capacitive accelerometer parameter.
In order to better implement the present invention, further, the specific operation of calculating the acceleration measurement in step 5 is as follows:
a det ＝Constant+Scale*ΔB
wherein DeltaB is closed-loop control quantity, constant is zero bias obtained by actual zero bias test, scale is Scale factor obtained by Scale factor test, a det Is an acceleration measurement.
Based on the high linearity control method of the MEMS closed-loop capacitive accelerometer, in order to better realize the invention, a MEMS closed-loop capacitive accelerometer control system is further provided and connected with the accelerometer; the accelerometer includes an accelerometer sensitive structure; the accelerometer sensitive structure comprises an upper polar plate, a lower polar plate, a middle polar plate and a mass block; the capacitive accelerometer closed-loop control system is characterized by comprising a processing module, a carrier module and a CV conversion module; the input end of the carrier module inputs a carrier signal, and the output end is connected with the middle polar plate; the middle polar plate is connected with the mass block; the input end of the CV conversion module is connected with the middle polar plate, and the output end of the CV conversion module is connected with the input end of the processing module; the output end of the processing module is connected with the upper polar plate and the lower polar plate;
The carrier module is used for modulating the carrier signal and an acceleration signal input to the accelerometer into a capacitance change signal;
the CV conversion module is used for demodulating the capacitance change signal into a differential analog voltage signal;
the processing module is used for converting the differential analog voltage signal into a differential digital voltage signal and generating a polar plate control voltage signal according to the differential digital voltage signal; then calculating closed-loop control quantity according to the polar plate control voltage signal; and calculates the voltage U applied to the upper polar plate according to the closed-loop control quantity T And a voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the Finally, eliminating the displacement of the mass block under the action of inertia force according to the electrostatic force generated by the polar plate control voltage signal and according to the voltage U T Voltage U B An acceleration measurement is calculated.
In order to better realize the invention, the processing module comprises a PID control module and a plate control voltage resolving module; the input end of the PID control module is connected with the output end of the CV conversion module, and the output end of the PID control module is connected with the input end of the plate control voltage resolving module; the output end of the plate control voltage calculating module is connected with the upper plate and the lower plate;
the PID control module is used for generating a polar plate control voltage signal according to the differential digital voltage signal and calculating closed-loop control quantity according to the polar plate control voltage signal;
A plate control voltage calculation module for calculating an upper plate voltage U applied to the upper plate according to the closed-loop control quantity and in combination with closed-loop capacitive accelerometer parameters T And a lower plate voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the Calculating an acceleration measurement value according to the closed-loop control quantity; the accelerometer parameters are used to indicate the maximum range obtained for the accelerometer.
To better implement the present invention, further, the closed-loop capacitive accelerometer control system further comprises a temperature sensor; the temperature sensor is connected with the processing module;
the temperature sensor is used for measuring temperature information of the accelerometer sensitive structure;
and the processing module is also used for compensating the drift of the accelerometer sensitive structure due to temperature according to the temperature information and generating an acceleration measurement value after temperature compensation.
In order to better realize the invention, further, the closed-loop capacitive accelerometer control system also comprises an analog-to-digital converter, a first digital-to-analog converter and a second digital-to-analog converter;
the input end of the analog-to-digital converter is connected with the input end of the CV conversion module, and the output end of the analog-to-digital converter is connected with the input end of the processing module;
the input end of the first digital-to-analog converter is connected with the output end of the processing module, and the output end of the first digital-to-analog converter is lapped between the upper polar plate and the first input end of the CV conversion module;
The input end of the second digital-to-analog converter is connected with the output end of the processing module, and the output end of the second digital-to-analog converter is lapped between the lower polar plate and the second input end of the CV conversion module.
To better implement the present invention, further, the closed-loop capacitive accelerometer control system also includes a high pass filter;
the first input end of the high-pass filter is connected with the upper polar plate and the output end of the first digital-to-analog converter, the second input end of the high-pass filter is connected with the lower polar plate and the output end of the second digital-to-analog converter, the first output end of the high-pass filter is connected with the first input end of the CV conversion module, and the second output end of the high-pass filter is connected with the second input end of the CV conversion module;
the high-pass filter is used for isolating low-frequency polar plate control voltage analog signals generated by the first digital-to-analog converter and the second digital-to-analog converter and conducting high-frequency capacitance change signals generated by the accelerometer sensitive structure.
To better implement the present invention, further, the closed-loop capacitive accelerometer control system further comprises a power module; the power supply module comprises a direct current converter, a first voltage stabilizer and a second voltage stabilizer;
the input end of the direct current transformer inputs external voltage, and the output end of the direct current transformer is connected with the input end of the first voltage stabilizer;
The output end of the first voltage stabilizer is connected with the input ends of the carrier module, the first digital-to-analog converter, the second digital-to-analog converter and the second voltage stabilizer;
the output end of the second voltage stabilizer is connected with the analog-to-digital converter and the processing module;
the direct current converter is used for converting the external voltage into a 6v stable voltage;
a first voltage regulator for converting a 6v regulated voltage to a 5v regulated voltage;
and a second voltage regulator for converting the 5v regulated voltage to a 3.3v regulated voltage.
To better implement the present invention, further, the closed-loop capacitive accelerometer control system further comprises a communication module; the input end of the communication module inputs an external communication signal and is connected with the output end of the processing module, and the output end of the communication module outputs an acceleration measurement value.
The invention has the following beneficial effects:
(1) Under the condition of no extra nonlinear compensation, the invention counteracts the inertial force generated by the mass block under the action of acceleration through the electrostatic force generated by applying voltage, calculates the acceleration measured value according to the closed-loop control quantity, reduces the operation quantity, improves the linearity of the closed-loop capacitive accelerometer, and further improves the performance of the closed-loop capacitive accelerometer.
(2) The control system provided by the invention has the characteristics of simple structure and high sensitivity, and the provided control method is suitable for all MEMS differential capacitive accelerometers, especially sandwich accelerometers, and can realize high-linearity digital closed-loop control under the non-ideal conditions of processing errors, asymmetric detection circuits and the like of the variable-spacing capacitive accelerometers.
Drawings
FIG. 1 is a schematic diagram of a control system according to the present invention;
FIG. 2 is a schematic diagram of signal transmission of a closed-loop control method according to the present invention;
fig. 3 is a schematic diagram of a sensitive structure according to an embodiment of the present invention.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it should be understood that the described embodiments are only some embodiments of the present invention, but not all embodiments, and therefore should not be considered as limiting the scope of protection. All other embodiments, which are obtained by a worker of ordinary skill in the art without creative efforts, are within the protection scope of the present invention based on the embodiments of the present invention.
In the description of the present invention, it should be noted that, unless explicitly stated and limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; or may be directly connected, or may be indirectly connected through an intermediate medium, or may be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Example 1:
the embodiment of the application provides a high-linearity control method of an MEMS closed-loop capacitive accelerometer, which is used for eliminating displacement generated by the closed-loop capacitive accelerometer under the action of inertia force; as shown in fig. 2, the method comprises the steps of:
step 1: generating a carrier signal, and modulating the carrier signal and an acceleration signal input into a closed-loop capacitive accelerometer into a capacitance change signal;
step 2: demodulating the capacitance change signal into a differential analog voltage signal and converting the differential analog voltage signal into a differential digital voltage signal;
Step 3: generating a closed-loop control amount required for closed-loop control according to the differential digital voltage signal, and calculating an upper plate voltage U applied to the upper plate according to the closed-loop control amount T And a lower plate voltage U applied to the lower plate B ；
Step 4: according to the upper plate voltage U applied to the upper plate T And the electrostatic force generated by the lower plate voltage UB applied to the lower plate eliminates the inertial force to which the mass block of the closed-loop capacitive accelerometer is sensitive under acceleration, and calculates an acceleration measurement value according to the closed-loop control quantity.
Further, the specific operation of the step 4 is as follows: calculating an upper plate voltage U applied to the upper plate according to the closed-loop control quantity and in combination with closed-loop capacitive accelerometer parameters T And a lower plate voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the The closed-loop capacitive accelerometer parameter is used to indicate a maximum range obtained by the closed-loop capacitive accelerometer.
Further, the calculation applies an upper plate voltage U to the upper plate T The specific operation of (a) is as follows:
calculating a bottom plate voltage U applied to the bottom plate B The specific operation of (a) is as follows:
wherein Δb is the closed-loop control quantity, and B is the closed-loop capacitive accelerometer parameter.
In order to better implement the present invention, further, the specific operation of calculating the acceleration measurement in step 5 is as follows:
a det ＝Constant+Scale*ΔB
wherein DeltaB is closed-loop control quantity, constant is zero bias obtained by actual zero bias test, scale is Scale factor obtained by Scale factor test, a det Is an acceleration measurement.
Working principle: the embodiment calculates the voltage U applied to the upper polar plate by calculating the closed-loop control quantity without additional non-compensation T And a voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the The inertial force of the mass block is eliminated through the electrostatic force generated by the applied voltage, and the acceleration measurement value is calculated according to the closed-loop control quantity, so that the linearity of the closed-loop capacitive accelerometer is improved while the operation quantity is reduced, and the performance of the closed-loop capacitive accelerometer is further improved.
Example 2:
based on the above embodiment 1, as shown in fig. 1, this embodiment proposes a MEMS closed-loop capacitive accelerometer control system connected to an accelerometer; the accelerometer includes an accelerometer sensitive structure; the accelerometer sensitive structure comprises an upper polar plate, a lower polar plate, a middle polar plate and a mass block; the capacitive accelerometer closed-loop control system is characterized by comprising a processing module, a carrier module and a CV conversion module; the input end of the carrier module inputs a carrier signal, and the output end is connected with the middle polar plate; the middle polar plate is connected with the mass block; the input end of the CV conversion module is connected with the middle polar plate, and the output end of the CV conversion module is connected with the input end of the processing module; the output end of the processing module is connected with the upper polar plate and the lower polar plate;
The carrier module is used for modulating the carrier signal and an acceleration signal input to the accelerometer into a capacitance change signal;
the CV conversion module is used for demodulating the capacitance change signal into a differential analog voltage signal;
the processing module is used for converting the differential analog voltage signal into a differential digital voltage signal and generating a polar plate control voltage signal according to the differential digital voltage signal; then calculating closed-loop control quantity according to the polar plate control voltage signal; and calculates the voltage U applied to the upper polar plate according to the closed-loop control quantity T And a voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the Finally, eliminating the displacement of the mass block under the action of inertia force according to the electrostatic force generated by the polar plate control voltage signal and according to the voltage U T Voltage U B An acceleration measurement is calculated.
Further, the processing module comprises a PID control module and a plate control voltage resolving module; the input end of the PID control module is connected with the output end of the CV conversion module, and the output end of the PID control module is connected with the input end of the plate control voltage resolving module; the output end of the plate control voltage calculating module is connected with the upper plate and the lower plate;
the PID control module is used for generating a polar plate control voltage signal according to the differential digital voltage signal and calculating closed-loop control quantity according to the polar plate control voltage signal;
A plate control voltage calculation module for calculating an upper plate voltage U applied to the upper plate according to the closed-loop control quantity and in combination with closed-loop capacitive accelerometer parameters T And a lower plate voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the Calculating an acceleration measurement value according to the closed-loop control quantity; the accelerometer parameters are used to indicate the maximum range obtained for the accelerometer.
Further, the closed-loop capacitive accelerometer control system further comprises a temperature sensor; the temperature sensor is connected with the processing module;
the temperature sensor is used for measuring temperature information of the accelerometer sensitive structure;
and the processing module is also used for compensating the drift of the accelerometer sensitive structure due to temperature according to the temperature information and generating an acceleration measurement value after temperature compensation.
Further, the closed-loop capacitive accelerometer control system further comprises an analog-to-digital converter, a first digital-to-analog converter and a second digital-to-analog converter;
the input end of the analog-to-digital converter is connected with the input end of the CV conversion module, and the output end of the analog-to-digital converter is connected with the input end of the processing module;
the input end of the first digital-to-analog converter is connected with the output end of the processing module, and the output end of the first digital-to-analog converter is lapped between the upper polar plate and the first input end of the CV conversion module;
The input end of the second digital-to-analog converter is connected with the output end of the processing module, and the output end of the second digital-to-analog converter is lapped between the lower polar plate and the second input end of the CV conversion module.
Further, the closed-loop capacitive accelerometer control system further comprises a high pass filter;
the first input end of the high-pass filter is connected with the upper polar plate and the output end of the first digital-to-analog converter, the second input end of the high-pass filter is connected with the lower polar plate and the output end of the second digital-to-analog converter, the first output end of the high-pass filter is connected with the first input end of the CV conversion module, and the second output end of the high-pass filter is connected with the second input end of the CV conversion module;
the high-pass filter is used for isolating low-frequency polar plate control voltage analog signals generated by the first digital-to-analog converter and the second digital-to-analog converter and conducting high-frequency capacitance change signals generated by the accelerometer sensitive structure.
Further, the closed-loop capacitive accelerometer control system further comprises a power module; the power supply module comprises a direct current converter, a first voltage stabilizer and a second voltage stabilizer;
the input end of the direct current transformer inputs external voltage, and the output end of the direct current transformer is connected with the input end of the first voltage stabilizer;
The output end of the first voltage stabilizer is connected with the input ends of the carrier module, the first digital-to-analog converter, the second digital-to-analog converter and the second voltage stabilizer;
the output end of the second voltage stabilizer is connected with the analog-to-digital converter and the processing module;
the direct current converter is used for converting the external voltage into a 6v stable voltage;
a first voltage regulator for converting a 6v regulated voltage to a 5v regulated voltage;
and a second voltage regulator for converting the 5v regulated voltage to a 3.3v regulated voltage.
Further, the closed-loop capacitive accelerometer control system further comprises a communication module; the input end of the communication module inputs an external communication signal and is connected with the output end of the processing module, and the output end of the communication module outputs an acceleration measurement value.
Other portions of this embodiment are the same as those of embodiment 1 described above, and thus will not be described again.
Example 3:
in this embodiment, on the basis of any one of the above embodiments 1-2, as shown in fig. 1, 2 and 3, the processing module and the communication module are integrated on a DSP chip, and the DSP, the analog-to-digital converter and the temperature sensor are integrated on an MCU chip, so that a specific embodiment will be described in detail.
The embodiment provides a high-linearity digital closed-loop control method suitable for MEMS closed-loop variable-spacing differential capacitive accelerometers, particularly sandwich structure accelerometers, wherein the closed-loop control method can realize theoretical complete linear closed-loop control under the actual condition of poor differential capacitance symmetry; the embodiment also provides a plate-level closed-loop capacitive accelerometer control system which can be applied to the control method and has the advantages of simple structure and low cost.
Wherein, a MEMS closed loop capacitive accelerometer control system, it includes:
the power module comprises a direct current converter, a voltage stabilizer and a power reference;
the direct current converter converts a wide-range external wide-range direct current power supply input into a stable voltage;
the voltage stabilizer converts the stable voltage output by the direct current converter into the voltage required by each electric device;
the power supply is used for outputting reference voltage with higher precision to the ADC and the DAC;
the carrier module can generate a high-frequency carrier wave with the MHz level and input the carrier wave into the accelerometer sensitive structure so as to modulate a capacitance change signal of the accelerometer sensitive structure to high frequency;
the carrier module and the CV conversion module jointly act to detect capacitance change caused by displacement of a mass block of the accelerometer sensitive structure, and then the capacitance change is converted into analog voltage, the carrier module generates a high-frequency carrier signal to modulate the capacitance change signal of the accelerometer sensitive structure to high frequency, and the CV conversion module demodulates the modulated high-frequency carrier signal containing the capacitance change signal into an analog voltage signal related to the capacitance change signal.
The accelerometer sensitive structure is manufactured by MEMS technology and comprises at least three or three groups of electrodes, wherein at least one pair of fixed differential electrodes and a movable electrode which can move under the action of inertial force, namely a middle electrode, two or two groups of differential capacitors are formed between the movable electrode and the fixed electrode, and the size of the differential capacitors can be changed under the action of inertial force;
the accelerometer sensitive structure comprises a middle electrode which has a certain mass, can sense inertia force and can generate certain elastic displacement under the action of the inertia force, and also comprises one or a group of top electrodes and one or a group of bottom electrodes, wherein the top electrodes and the bottom electrodes are almost symmetrical relative to the middle electrode, the top electrodes, the middle electrode, the bottom electrodes and the middle electrode form a capacitor, and the displacement of the middle electrode can change the distance between the capacitors so as to change the size of the capacitors.
The high-pass filter can pass the capacitance change signal modulated to the MHz high frequency and filter the KHz low-frequency control signal output by the DAC;
the high-pass filter isolates low-frequency analog voltage signals output by the first analog-to-digital converter and the second analog-to-digital converter, and meanwhile, carrier signals which pass through the accelerometer sensitive structure and modulate mass block change information to high frequency can reach the CV conversion module through the high-pass filter, so that detection/control multiplexing of the top electrode and the bottom electrode is realized.
The CV conversion module is a capacitance-voltage conversion module, and the module demodulates the capacitance change signal modulated at high frequency and outputs the capacitance change signal to the ADC as a differential voltage signal;
the ADC is an analog-to-digital converter, and the module converts the differential analog voltage signal generated by the CV conversion module into digital quantity for the processing module to use;
the analog-to-digital converter converts the analog voltage signal related to the capacitance change signal into a digital signal, outputs the digital signal to the first digital-to-analog converter and the second digital-to-analog converter to output a low-frequency control voltage signal to be output to the accelerometer sensitive structure after being controlled by the processing module, and outputs the temperature compensated acceleration measured value after obtaining the temperature information of the temperature sensor outwards through the serial communication module.
DAC1 and DAC2, wherein the DAC1 and DAC2 are a first digital-to-analog converter and a second digital-to-analog converter, and the DAC1 and DAC2 convert the digital voltage control quantity calculated by the processing module into an actual analog control voltage signal;
the DAC1 and the DAC2 are manufactured by the same process, come from a single-chip double-DAC module and use the same reference voltage;
the first digital-to-analog converter and the second digital-to-analog converter convert the low-frequency control voltage signal output by the processing module into low-frequency analog control voltage and act on the top electrode and the bottom electrode of the accelerometer sensitive structure.
The DSP is a digital signal processing module and comprises a processing module and an SPI/serial port module;
the processing module acquires the position information and the temperature information of the accelerometer sensitive structure mass block from the ADC and the temperature sensor directly or through the SPI/serial port module, performs a closed-loop control method, calculates to obtain a digital voltage control quantity and an acceleration measured value, then transmits the digital voltage control quantity to the DAC1 and the DAC2 directly or through the SPI/serial port module, and outputs the acceleration measured value and the temperature information directly or through the SPI/serial port module;
the SPI/serial port module is a communication module and is used for outputting data in the DSP in series or inputting external information in series;
the temperature sensor is used for measuring the temperature information of the whole accelerometer module and transmitting the measured temperature information to the processing module directly or through the SPI/serial port module so as to correct the influence of temperature on the acceleration measurement value;
preferably, the temperature sensor is arranged at the nearest part of the accelerometer sensitive structure;
preferably, the MCU is a micro control unit, which integrates an ADC, a temperature sensor and a DSP into a single chip, reduces the area of a device and improves the signal transmission rate;
The high-linearity digital closed-loop control method is executed in a processing module, and displacement information of a mass block of an accelerometer sensitive structure under the action of inertia force is obtained by obtaining voltage information periodically output by an analog-to-digital converter; periodically transmitting the displacement information to a PID controller to obtain a control quantity which can dynamically regulate and control a mass block of the accelerometer sensitive structure to be at a set position, resolving the control quantity into a control voltage through a polar plate voltage, and outputting the control voltage to a first digital-to-analog converter and a second digital-to-analog converter; periodically resolving the control quantity into a measured acceleration value, acquiring a temperature value of a temperature sensor to calibrate the temperature drift of the measured acceleration, and outputting a final acceleration measured value.
The differential voltage signal DeltaV obtained from the ADC is subjected to real-time operation by a PID module to obtain a control quantity DeltaB for closed-loop control, so that the DeltaV is controlled to a fixed value, namely, the mass block of the sensitive structure is controlled to a fixed position to eliminate nonlinearity caused by the sensitive structure and the CV conversion module; the control amount DeltaB obtained by PID operation is calculated by the following formula to obtain the voltage U output to the upper plate T And the voltage U of the lower polar plate B ：
Where B is a constant, the measured and output acceleration a det The method can be solved as follows:
a det ＝Constant+Scale*ΔB
wherein, constant and Scale are zero bias Constant and Scale factor Scale obtained by actual zero bias and Scale factor test;
preferably, the constant B takes the value:
B＝U TMAX 2 /2
to maximize the range of the accelerometer, where U TMAX Maximum voltage that can be output for DAC1 and DAC 2;
preferably, the voltage U of the intermediate plate M Take the value U M =0v to achieve the simplest control;
the high linearity digital closed loop control method is that when the variable-interval differential capacitance accelerometer is in a sensitive structure, two or two pairs of differential electrodes are asymmetric, and the initial interval between the two pairs of differential electrodes and the middle electrode where the sensitive mass block is positioned is d respectively T 、d B After the CV conversion circuit and the ADC have certain error detection, the position of the mass block at 0g is controlled to shift by d x The distance between the upper polar plate and the middle polar plate when the closed-loop control is stable is:
d 1 ＝d T -d x
the distance between the lower polar plate and the middle polar plate is as follows:
d 2 ＝d T +d x
the above-mentioned processing errors and detection errors which cannot be completely eliminated can cause the measured acceleration a under the existing closed-loop control method det The non-linearity with the actual acceleration a, under the control method herein, the theoretical acceleration can be solved by the electrostatic and inertial forces applied to the mass counteracting:
F Inertial force ＝-m*a
Closed loop control causes the sum of electrostatic and inertial forces to:
F electrostatic force +F Inertial force ＝0
The method can be solved as follows:
wherein epsilon is the dielectric constant of a medium between polar plates, A is the capacitance area of the polar plates, and m is the mass of a sensitive mass block;
because ofThen U T 2 ＝B+ΔB，U B 2 =b- Δb, brought to a above det Is obtained from the theoretical calculation formula:
wherein,wherein ε, A, B, m, d 1 、d 2 Both are Constant, constant1 and Scale1 are Constant, and the theoretical acceleration a is linearly related to the control amount Δb, due to the measured acceleration a det Linearly dependent on Δb, the theoretical acceleration a is then related to the measured acceleration a det The linear correlation, the differential capacitance asymmetry generated by processing, the detection errors of the CV conversion circuit and the ADC are completely eliminated under the high linearity closed loop control method, and a nonlinear term is not generated.
The closed-loop capacitive accelerometer control system of the embodiment is embodied as a plate-level high linearity MEMS closed-loop capacitive accelerometer.
A closed-loop capacitive accelerometer control system as shown in fig. 1 coupled to an accelerometer sensitive structure, the closed-loop capacitive accelerometer control system comprising: the device comprises a carrier module, a high-pass filter, a capacitor-voltage conversion module, a first digital-to-analog converter, a second digital-to-analog converter, an MCU microcontroller and a power module.
The power supply module comprises a DCDC chip and an LDO chip; the DCDC chip can convert external power supply with a wider range into power supply with a voltage greater than 6V, and any DCDC chip with an output of 6V which meets the power consumption of the whole accelerometer system can be selected; one of the LDO chips converts the voltage greater than 6V converted by the DCDC into a stable 5V power supply for the carrier module, the first digital-to-analog converter and the second digital-to-analog converter, and the other LDO chip converts the stable 5V power supply into a stable 3.3V voltage for the microcontroller.
The carrier module is powered by a power supply module, generates a high-frequency square wave of 4MHz by using a crystal oscillator and is connected with a high-pass filter to enable the effective value of an output carrier to be 0V and the amplitude to be 2.5V; the output carrier is directly connected to the electrode where the sensing mass of the accelerometer sensing structure is located.
The accelerometer sensitive structure uses a sandwich structure shown in fig. 3, and comprises a top electrode positioned at the top of an intermediate electrode where a sensitive mass is positioned and a bottom electrode positioned at the bottom of the intermediate electrode; the parallel plate capacitor plate spacing between the top electrode and the middle electrode, and between the bottom electrode and the middle electrode 17 is about 2 microns, the thickness of the middle electrode where the mass block is located is 400 microns, and the capacitance area is 3.2 square millimeters; the sensitive mass on the intermediate electrode is movable under inertial force to vary its distance d from the top and bottom electrodes 1 And d 2 Thereby changing the capacitance C with the top electrode and the bottom electrode 1 And C 2 Size of the product.
The high-pass filter is a passive RC high-pass filter, the high-frequency square wave generated by the carrier wave module can pass through the high-frequency filter completely through the accelerometer sensitive structure, and the low-frequency control voltage signal applied to the accelerometer sensitive structure by the first digital-analog converter and the second digital-analog converter can hardly pass through the high-pass filter, so that the detection signal and the control signal share a pair of differential electrodes without mutual influence.
The CV conversion module demodulates the capacitance change signal modulated by the accelerometer sensitive structure into a voltage signal for being read by the analog-to-digital converter, and the CV conversion module can use a ring diode capacitance detection structure with a simpler structure.
The analog-to-digital converter measures differential voltage signals generated by the capacitance change of the accelerometer sensitive structure, converts the differential voltage signals into digital quantities and directly reads the digital quantities by the processing module.
The processing module runs the control method in the embodiment, the input differential control signal passes through the PID controller to obtain the control quantity, then the control quantity is subjected to squaring and other operations to obtain the polar plate control voltage, and the polar plate control voltage is output to the analog-digital converter integrated by the first digital-analog converter and the second analog-digital converter through the SPI/serial port module. Meanwhile, the acceleration measured value after temperature drift correction is output in real time through the SPI/serial port module according to the temperature sensor.
The analog-to-digital converter, the processing module and the SPI/serial port module are integrated in an independent microcontroller chip so as to save the board-level circuit area.
The control method of the present embodiment is specifically implemented as follows:
the high linearity closed-loop control method is operated in the MEMS closed-loop capacitive accelerometer embodiment in which the accelerometer sensitive structure is in a variable capacitance pole plate spacing mode. The following implementation process is an implementation process in one execution period, the closed loop control is control for continuously and circularly executing the implementation process along with time, and the single execution period implementation process is as follows: the closed-loop control method executed by the calculation program runs in the microcontroller, reads the capacitance change information about the accelerometer sensitive structure output by the analog-to-digital converter 7 integrated by the chip, and calculates the real-time output control quantity through the PID controller, wherein the control quantity has the effect of controlling the mass block of the accelerometer sensitive structure to a set fixed position; the control quantity delta B output by the PID controller is calculated by the polar plate control voltage to obtain the sensitive structure to be applied to the accelerometerControl voltage data U for top and bottom electrodes T And U B The analog voltage is output to the accelerometer sensitive structure through SPI/serial port serial output to the DAC chip integrated by the first analog-digital converter and the second analog-digital converter; the implementation of the high-linearity digital closed-loop control method of the single execution period is completed. Wherein the control voltage data U T And U B The solution equation of (2) is:
wherein B is a constant, the recommended value is:
B＝U TMAX 2 /2
U TMAX the maximum voltage can be output by the DAC chip, the visual representation of the value of B is that the voltage applied to the top electrode and the bottom electrode is equal to the ideal value of 0gThe value of B is larger, so that the closed loop system is unstable, and the value of B can be properly reduced.
The high linearity digital closed-loop control method disclosed by the invention can be operated on any controller capable of executing digital program operation, and can be applied to a closed-loop control system to control any capacitance-variable distance type accelerometer sensitive structure so that the closed-loop capacitive accelerometer can obtain high linearity without nonlinear correction.
The working flow of the closed-loop capacitive accelerometer control system of the embodiment is as follows:
when the carried carrier has acceleration in the sensitive direction of the accelerometer, the sensitive mass block 18 of the accelerometer sensitive structure can feel inertia force due to certain mass sensitivity;
the sensitive mass block can displace under the action of inertial force to change the distance d between polar plates of the sensitive structure of the accelerometer 1 And d 2 Thereby causing a capacitance C 1 And C 2 Is a change in (2);
sensitive structure capacitance C 1 And C 2 The change of the voltage signal is changed into a differential voltage signal delta V through the detection and conversion of the CV conversion module and the analog-to-digital converter, so that the processing module reads the deviation of the mass block from the original position and the deviation delta V;
After the PID controller and the polar plate control voltage are resolved, the processing module outputs a control voltage signal U T And U B So that the DAC chip outputs analog control voltage;
the DAC chip outputs analog control voltage to act on the top electrode and the bottom electrode of the accelerometer sensitive structure, displacement of the mass block under the action of inertia force is eliminated by the action of the electrostatic force under the action of the electrostatic force, and after the multi-wheel control reaches a steady state, the electrostatic force is approximately equal to the inertia force;
the processing module solves the electrostatic force generated by the control voltage to obtain a measured acceleration value, corrects drift generated by temperature influence by acquiring temperature information of the temperature sensor, and outputs the corrected acceleration measurement value through the SPI/serial port module.
The control system provided by the embodiment has the advantages of low cost and simple structure; meanwhile, the control method provided by the embodiment can completely eliminate nonlinear items caused by processing errors and differential capacitance detection errors under the condition of not carrying out additional nonlinear compensation, is small in calculation amount, theoretically does not need to compensate to obtain a complete linear relation between input acceleration and detection acceleration, is beneficial to improving the linearity of the current closed-loop capacitive accelerometer, further improves the performance of the high-precision closed-loop capacitive accelerometer, and theoretically completely solves the problem that the output measured acceleration value does not need to carry out any nonlinear compensation, and is nonlinear caused by offset in the acquisition of mass block position information, such as a carrier module, a high-pass filter, a CV conversion module and an analog-digital converter module, of a capacitive distance processing error of an accelerometer sensitive structure.
Other portions of this embodiment are the same as any of embodiments 1-2 described above, and thus will not be described again.
The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent variation, etc. of the above embodiment according to the technical matter of the present invention fall within the scope of the present invention.
Claims (7)
1. A method for high linearity control of a MEMS closed-loop capacitive accelerometer, the method comprising the steps of:
step 1: generating a carrier signal, and modulating the carrier signal and an acceleration signal input into a closed-loop capacitive accelerometer into a capacitance change signal;
step 2: demodulating the capacitance change signal into a differential analog voltage signal and converting the differential analog voltage signal into a differential digital voltage signal;
step 3: generating a closed-loop control quantity required by closed-loop control according to the differential digital voltage signal, and calculating an upper plate voltage U applied to an upper plate according to the closed-loop control quantity T And a lower plate voltage U applied to the lower plate B ；
Step 4: according to the upper plate voltage U applied to the upper plate T And a lower plate voltage U applied to the lower plate B The generated electrostatic force eliminates the inertial force which is sensed by the mass block of the closed-loop capacitive accelerometer under acceleration, and calculates an acceleration measurement value according to the closed-loop control quantity;
the specific operation of the step 3 is as follows: calculating an upper plate voltage U applied to the upper plate according to the closed-loop control quantity and in combination with closed-loop capacitive accelerometer parameters T And a lower plate voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the The closed-loop capacitive accelerometer parameter is used for indicating the maximum range obtained by the closed-loop capacitive accelerometer;
the calculation of the upper plate voltage U applied to the upper plate T The specific operation of (a) is as follows:
calculating a bottom plate voltage U applied to the bottom plate B The specific operation of (a) is as follows:
wherein,is a closed-loop control quantity->Is a closed-loop capacitive accelerometer parameter;
B=U TMAX 2 /2
wherein U is TMAX Maximum voltage that can be output for DAC1 and DAC 2;
the specific operation of calculating the acceleration measurement value in the step 4 is as follows:
wherein DeltaB is closed-loop control quantity, constant is zero bias obtained by an actual zero bias test, scale is a Scale factor obtained by a Scale factor test,is an acceleration measurement.
2. A MEMS closed-loop capacitive accelerometer control system connected with a closed-loop capacitive accelerometer; the closed-loop capacitive accelerometer comprises an accelerometer sensitive structure; the accelerometer sensitive structure comprises an upper polar plate, a lower polar plate, a middle polar plate and a mass block; the closed-loop control system of the closed-loop capacitive accelerometer is characterized by comprising a processing module, a carrier module and a CV conversion module; the input end of the carrier module inputs a carrier signal, and the output end of the carrier module is connected with the middle polar plate; the middle polar plate is connected with the mass block; the input end of the CV conversion module is connected with the middle polar plate, and the output end of the CV conversion module is connected with the input end of the processing module; the output end of the processing module is connected with the upper polar plate and the lower polar plate;
The carrier module is used for modulating the carrier signal and an acceleration signal input into the closed-loop capacitive accelerometer into a capacitance change signal;
the CV conversion module is used for demodulating the capacitance change signal into a differential analog voltage signal;
the processing module is used for converting the differential analog voltage signal into a differential digital voltage signal and generating a polar plate control voltage signal according to the differential digital voltage signal; then, a closed-loop control amount required by closed-loop control is generated according to the differential digital voltage signal, and an upper plate voltage U applied to the upper plate is calculated according to the closed-loop control amount T And a lower plate voltage U applied to the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the Finally according to the upper plate voltage U applied to the upper plate T And a lower plate voltage U applied to the lower plate B The generated electrostatic force eliminates the inertial force which is sensed by the mass block of the closed-loop capacitive accelerometer under acceleration, and calculates an acceleration measurement value according to the closed-loop control quantity;
the processing module comprises a PID control module and a plate control voltage resolving module; the input end of the PID control module is connected with the output end of the CV conversion module, and the output end of the PID control module is connected with the input end of the plate control voltage resolving module; the output end of the plate control voltage resolving module is connected with the upper plate and the lower plate;
The PID control module is used for generating a polar plate control voltage signal according to the differential digital voltage signal and calculating a closed-loop control quantity according to the polar plate control voltage signal;
the plate control voltage calculation module is used for calculating the upper plate voltage U applied to the upper plate according to the closed-loop control quantity and the closed-loop capacitive accelerometer parameters T And applied to a houseLower plate voltage U of the lower plate B The method comprises the steps of carrying out a first treatment on the surface of the Calculating an acceleration measurement value according to the closed-loop control quantity;
the closed-loop capacitive accelerometer parameter is used for indicating the maximum range obtained by the closed-loop capacitive accelerometer;
the calculation of the upper plate voltage U applied to the upper plate T The specific operation of (a) is as follows:
calculating a bottom plate voltage U applied to the bottom plate B The specific operation of (a) is as follows:
wherein,is a closed-loop control quantity->Is a closed-loop capacitive accelerometer parameter;
B=U TMAX 2 /2
wherein U is TMAX Is the maximum voltage that DAC1 and DAC2 can output.
3. The MEMS closed-loop capacitive accelerometer control system of claim 2, wherein the closed-loop capacitive accelerometer control system further comprises a temperature sensor; the temperature sensor is connected with the processing module;
The temperature sensor is used for measuring temperature information of the accelerometer sensitive structure;
the processing module is further used for compensating the drift of the accelerometer sensitive structure due to temperature according to the temperature information and generating an acceleration measurement value after temperature compensation.
4. The MEMS closed-loop capacitive accelerometer control system of claim 2, wherein the processing module further comprises an analog-to-digital converter, a first digital-to-analog converter, a second digital-to-analog converter;
the input end of the analog-to-digital converter is connected with the input end of the CV conversion module, and the output end of the analog-to-digital converter is connected with the input end of the processing module;
the input end of the first digital-to-analog converter is connected with the output end of the processing module, and the output end of the first digital-to-analog converter is lapped between the upper polar plate and the first input end of the CV conversion module;
the input end of the second digital-to-analog converter is connected with the output end of the processing module, and the output end of the second digital-to-analog converter is lapped between the lower polar plate and the second input end of the CV conversion module.
5. The MEMS closed-loop capacitive accelerometer control system of claim 4, wherein the closed-loop capacitive accelerometer control system further comprises a high pass filter;
The first input end of the high-pass filter is connected with the upper polar plate and the output end of the first digital-to-analog converter, the second input end of the high-pass filter is connected with the lower polar plate and the output end of the second digital-to-analog converter, the first output end of the high-pass filter is connected with the first input end of the CV conversion module, and the second output end of the high-pass filter is connected with the second input end of the CV conversion module;
the high-pass filter is used for isolating low-frequency polar plate control voltage analog signals generated by the first digital-to-analog converter and the second digital-to-analog converter and conducting high-frequency capacitance change signals generated by the accelerometer sensitive structure.
6. The MEMS closed-loop capacitive accelerometer control system of claim 4, wherein the closed-loop capacitive accelerometer control system further comprises a power module; the power supply module comprises a direct current converter, a first voltage stabilizer and a second voltage stabilizer;
the input end of the direct current converter inputs external voltage, and the output end of the direct current converter is connected with the input end of the first voltage stabilizer;
the output end of the first voltage stabilizer is connected with the input ends of the carrier module, the first digital-to-analog converter, the second digital-to-analog converter and the second voltage stabilizer;
The output end of the second voltage stabilizer is connected with the analog-to-digital converter and the processing module;
the direct current converter is used for converting the external voltage into a 6v stable voltage;
the first voltage stabilizer is used for converting the 6v stable voltage into a 5v stable voltage;
the second voltage stabilizer is used for converting the 5v stable voltage into 3.3v stable voltage.
7. The MEMS closed-loop capacitive accelerometer control system of claim 2, wherein the closed-loop capacitive accelerometer control system further comprises a communication module; the input end of the communication module inputs an external communication signal and is connected with the output end of the processing module, and the output end of the communication module outputs an acceleration measurement value and temperature information.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310046653.2A CN116125099B (en) | 2023-01-31 | 2023-01-31 | MEMS closed-loop capacitive accelerometer high linearity control method and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310046653.2A CN116125099B (en) | 2023-01-31 | 2023-01-31 | MEMS closed-loop capacitive accelerometer high linearity control method and system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116125099A CN116125099A (en) | 2023-05-16 |
| CN116125099B true CN116125099B (en) | 2024-01-19 |
Family
ID=86296902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310046653.2A Active CN116125099B (en) | 2023-01-31 | 2023-01-31 | MEMS closed-loop capacitive accelerometer high linearity control method and system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116125099B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6035694A (en) * | 1999-03-12 | 2000-03-14 | I/O Of Austin, Inc. | Method and apparatus for calibration of stray capacitance mismatch in a closed loop electro-mechanical accelerometer |
| CN103558417A (en) * | 2013-11-08 | 2014-02-05 | 中国工程物理研究院电子工程研究所 | Detection method and device thereof for charge balance type micro-accelerometer gauge head differential capacitor |
| CN106597015A (en) * | 2016-12-02 | 2017-04-26 | 电子科技大学 | Closed-loop circuit for promoting output stability of capacitance type silicon micro-acceleration sensor |
| CN114034884A (en) * | 2021-11-19 | 2022-02-11 | 中国工程物理研究院电子工程研究所 | Multi-differential capacitance type acceleration sensor |
| CN115184639A (en) * | 2022-05-12 | 2022-10-14 | 四川微著科技有限公司 | Closed-loop reading circuit of triaxial MEMS accelerometer |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3862757B1 (en) * | 2020-02-07 | 2024-03-27 | Atlantic Inertial Systems Limited | Methods for closed loop operation of capacitive accelerometers and such capacitive accelerometers |
-
2023
- 2023-01-31 CN CN202310046653.2A patent/CN116125099B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6035694A (en) * | 1999-03-12 | 2000-03-14 | I/O Of Austin, Inc. | Method and apparatus for calibration of stray capacitance mismatch in a closed loop electro-mechanical accelerometer |
| CN103558417A (en) * | 2013-11-08 | 2014-02-05 | 中国工程物理研究院电子工程研究所 | Detection method and device thereof for charge balance type micro-accelerometer gauge head differential capacitor |
| CN106597015A (en) * | 2016-12-02 | 2017-04-26 | 电子科技大学 | Closed-loop circuit for promoting output stability of capacitance type silicon micro-acceleration sensor |
| CN114034884A (en) * | 2021-11-19 | 2022-02-11 | 中国工程物理研究院电子工程研究所 | Multi-differential capacitance type acceleration sensor |
| CN115184639A (en) * | 2022-05-12 | 2022-10-14 | 四川微著科技有限公司 | Closed-loop reading circuit of triaxial MEMS accelerometer |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116125099A (en) | 2023-05-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5095750A (en) | Accelerometer with pulse width modulation | |
| CN101384882B (en) | Physical quantity sensor | |
| CN102879020B (en) | Method for reducing non-linearity during measurement of a physical parameter and electronic circuit for implementing the same | |
| US20200041537A1 (en) | Accelerometers | |
| US9535084B2 (en) | Method for the decoupled control of the quadrature and the resonance frequency of a micro-mechanical rotation rate sensor by means of sigma-delta-modulation | |
| CN108008152B (en) | Method and device for acquiring parasitic mismatch capacitance of MEMS accelerometer | |
| US10241128B2 (en) | Accelerometer control | |
| CN103558417A (en) | Detection method and device thereof for charge balance type micro-accelerometer gauge head differential capacitor | |
| CN103842829A (en) | Linear capacitance-to-voltage converter using a single amplifier for transducer front ends with cancellation of spurious forces contributed by sensor circuitry | |
| EP3321693B1 (en) | Accelerometer control | |
| CN103842831A (en) | Electrostatic capacitance detection circuit | |
| CN208847194U (en) | Driving circuit and MEMS gyroscope for MEMS gyroscope | |
| CN106289212B (en) | Integrated measurement and control unit for silicon micro tuning fork gyroscope | |
| CN101680910A (en) | Method of work and circuit structure with capacitance type micro mechanical sensor of analog reset | |
| CN113406357B (en) | Micro-mechanical accelerometer and calibration compensation method thereof | |
| CN116125099B (en) | MEMS closed-loop capacitive accelerometer high linearity control method and system | |
| CN111273203B (en) | Feedback control device with magnetic gradient measurement and suspended superconducting ball position | |
| CN114137253B (en) | Rigidity modulation MEMS accelerometer and closed-loop control method thereof | |
| CN115598377A (en) | Zero drift self-detection self-calibration system based on digital sigma delta closed-loop accelerometer | |
| CN107979351B (en) | Coupling piezoresistive MEMS oscillator based on high-order synchronization | |
| CN115184639A (en) | Closed-loop reading circuit of triaxial MEMS accelerometer | |
| CN111623759B (en) | Method for accelerating zero-offset stabilization time of micro-electromechanical gyroscope | |
| JPH0672901B2 (en) | Capacitance-voltage conversion circuit | |
| CN116164634A (en) | Capacitive MEMS structure electrode gap measurement system and method | |
| CN213041913U (en) | Range extender separation voltage sampling circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |