CN219179430U

CN219179430U - Piezoelectric accelerometer automatic calibration system based on FPGA

Info

Publication number: CN219179430U
Application number: CN202222670190.0U
Authority: CN
Inventors: 杨程; 李俊; 李长武; 金涛; 孔明; 刘璐
Original assignee: Suzhou Institute Of Metrology; China Jiliang University
Current assignee: Suzhou Institute Of Metrology; China Jiliang University
Priority date: 2022-10-11
Filing date: 2022-10-11
Publication date: 2023-06-13
Anticipated expiration: 2032-10-11

Abstract

The utility model discloses an automatic calibration system of a piezoelectric accelerometer based on an FPGA (field programmable gate array), which comprises a pneumatic impact calibration device, a pressure regulating controller, an automatic pressure regulating controller and a computer, wherein the pressure regulating controller is connected with the pneumatic impact calibration device through a gas circuit and an electric signal respectively, and provides compressed gas and pressure control and display for the pneumatic impact calibration device; the automatic pressure regulating controller is connected with the pressure regulating controller through an electric signal and is used for collecting the pressure signal, sending out a trigger signal and a motor control signal; the pressure regulating controller and the automatic pressure regulating controller are respectively connected with the electromechanical signals. The beneficial effects of the utility model are as follows: according to the system, on the basis of an existing impact generating device, an electromechanical control system based on a programmable array logic FPGA is developed to conduct automatic air pressure control, a virtual instrument platform is utilized to conduct software design by adopting a high-level graphic language LABVIEW, and automatic calibration of an accelerometer is achieved.

Description

Piezoelectric accelerometer automatic calibration system based on FPGA

Technical Field

The utility model relates to the technical field of accelerometer calibration devices, in particular to an automatic calibration system of a piezoelectric accelerometer based on an FPGA.

Background

The mechanical impact is a common physical phenomenon in daily life and engineering practice, can effectively evaluate the service life of bridges or instruments, check the correctness of structural design and the like, and has important significance in practical engineering application. The essence of the impact measurement is the measurement of acceleration, and the impact speed and displacement equivalent can be deduced according to the acceleration measurement result. Accelerometers are of various types, and can be classified into piezoresistive type, piezoelectric type, capacitive type, magnetoelectric type, optical fiber type and the like according to different measurement principles. The piezoelectric accelerometer adopts a piezoelectric element as a sensitive element, can autonomously generate an electric signal with a wide dynamic range, has the advantages of high resonant frequency, high sensitivity, small volume, light weight and the like, and has wide application in civil engineering, aerospace, weapon test and other aspects.

In order to ensure that the accelerometer used in actual work can accurately measure mechanical impact, the accelerometer needs to be measured and calibrated before leaving a factory or before use, and the most applied measuring and calibrating method is a laser interference absolute method and an impact comparison method. The absolute method is a laser interference absolute calibration method, wherein the surface provided with a sensor to be measured is used as a movable reflector of a laser Doppler system, when the surface is impacted, the system frequency is Doppler shifted, and the change condition of the speed of a moving body along with time can be determined by measuring the Doppler change of the light frequency. In an absolute method calibration system, a laser interferometry system is required to test an impact surface, the measurement precision is high (the acceleration value is directly reproduced by the basic quantity of time and length measurement), but the system is complex, the requirement on an instrument is high, and the system is generally used for calibrating a standard accelerometer. The comparison method is to install the calibrated accelerometer and the standard accelerometer in the calibration system at the same time to sense the same impact effect, and the performance of the calibrated angular velocity meter can be obtained by directly comparing the output quantities of the two accelerometers. The comparison method has the advantages of simple principle, convenient operation, low requirements on equipment and the like, is widely applied, is convenient for realizing the calibration among different levels in a calibration system, and is mainly used for the calibration of the working accelerometer.

The conventional comparison method calibration device in the metering industry in China comprises a pendulum type pneumatic piston type impact calibration device, but most of the conventional devices have the defect of insufficient automation degree. In the pneumatic piston type impact calibration device, the compressed gas pressure and the thickness of the anvil cushion are required to be changed to emit half sine waves with different impact accelerations and different impact pulse widths, but the air pressure adjustment of the existing equipment is required to be performed manually, so that the accelerometer metering process is longer in time consumption, lower in working efficiency and higher in experience requirements of metering staff.

Disclosure of Invention

In order to solve the problems in the prior art, the utility model provides an automatic calibration system of a piezoelectric accelerometer based on an FPGA, which has the advantages of reasonable structural design, high efficiency and simplicity and convenience in operation.

The technical scheme of the utility model is as follows:

the piezoelectric accelerometer automatic calibration system based on the FPGA comprises a pneumatic impact calibration device, a pressure regulation controller, an automatic pressure regulation controller and a computer, wherein the pressure regulation controller is connected with the pneumatic impact calibration device through a gas circuit and an electric signal respectively, and provides compressed gas and pressure control and display for the pneumatic impact calibration device; the automatic pressure regulating controller is connected with the pressure regulating controller through an electric signal and is used for collecting the pressure signal, sending out a trigger signal and a motor control signal; the pressure regulating controller and the automatic pressure regulating controller are respectively connected with the electromechanical signals.

Further, the automatic voltage regulation controller comprises an FPGA data processing circuit, a data acquisition circuit A/D, a digital-to-analog conversion circuit D/A1, a digital-to-analog conversion circuit D/A2 and a motor control circuit, wherein the data acquisition circuit A/D is connected with the FPGA data processing circuit, the FPGA data processing circuit is respectively connected with the digital-to-analog conversion circuit D/A1 and the digital-to-analog conversion circuit D/A2, and the digital-to-analog conversion circuit D/A1 is connected with the motor control circuit and is used for controlling the motor rotating mechanism to work.

Further, be equipped with air source switch, pressure adjustment mechanism, pressure display panel and pilot lamp on the pressure regulation controller, pressure adjustment mechanism includes electronic rotating head, adjust knob and installing support, adjust knob sets up on the pressure regulation controller, links to each other with its inside valve, electronic rotating head is connected with adjust knob transmission, and electronic rotating head passes through the installing support to be fixed on the pressure regulation controller shell.

Further, the installing support adopts the U type support, U type support one end is installed on pressure regulating controller shell spliced pole through the nut, and the other end links to each other with electronic rotating head.

Further, the installing support adopts the drum support, the both ends of drum support are equipped with a set of screw hole along the circumferencial direction, drum support one end is installed on pressure regulation controller shell spliced pole through the jackscrew, and the other end passes through the jackscrew and links to each other with electronic rotating head.

The beneficial effects of the utility model are as follows: according to the system, on the basis of an existing impact generating device, an electromechanical control system based on programmable array logic (FPGA) is developed to conduct automatic air pressure control, a virtual instrument platform is utilized to conduct software design by adopting a high-level graphic language LABVIEW, and automatic calibration of an accelerometer is achieved.

Drawings

FIG. 1 is a schematic view of the overall mounting structure of the present utility model;

FIG. 2 is a U-shaped bracket mounting view of the present utility model;

FIG. 3 is a cylinder mount view of the present utility model;

FIG. 4 is a circuit diagram of the internal circuitry of the automatic voltage regulator controller of the present utility model;

FIG. 5 is an FPGA internal operation diagram of the present utility model;

FIG. 6 is a workflow diagram of the present utility model;

in the figure: 1. pneumatic impact calibration means; 101. a measured accelerometer; 102. a restraint clamp; 103. an additional mass; 104. an anvil block; 105. a piston; 106. a barrel; 107. a poppet valve; 108. a pressure regulator; 2. a pressure regulating controller; 201. an air source switch; 202. a pressure regulating mechanism; 2021. an electric rotating head; 2022. an adjustment knob; 2023. a U-shaped bracket; 2024. a nut; 2025. a cylindrical holder; 203. a pressure display panel; 204. an indicator light; 3. an automatic pressure regulating controller; 4. and a computer.

Detailed Description

The utility model is further described below with reference to the drawings.

As shown in the figure, the piezoelectric accelerometer automatic calibration system based on the FPGA mainly comprises four parts: the impact calibration table and the pressure regulation controller are existing equipment, and are specifically a pneumatic impact calibration device with the model number of SC-7103 and a pneumatic impact regulation controller with the model number of SC-2, which are produced by Hangzhou Yiheng technology limited companies.

Calibration principle: the measured accelerometer 101 is mounted back-to-back with the standard accelerometer on an anvil 104, and the anvil 104 is placed on top of the barrel 106. When the firing switch is activated, pilot poppet 107 releases compressed gas, piston 105 impacts upward from the bottom of barrel 106 and strikes anvil 104, anvil 104 lifts from the top of barrel 106, and after a short distance of travel, is decelerated by the cushioning device. The pressure of the compressed gas released by the poppet valve 107 is controlled by a pressure regulating mechanism and displayed by a pressure gauge, and the "ready to fire" indicator lamp 204 is in a normally on state when the pressure is adjusted. The magnitude of the impact acceleration is not only dependent on the gas pressure, but also on the additional mass and the thickness of the pad, and different impact pulse widths can be achieved during the experiment by selecting different anvil, additional mass and pad thickness combinations.

In order to achieve the aim of automatic verification, a manual adjusting device for pressure adjustment is replaced by an electric rotating mechanism (piezoelectric screw) on the basis of the existing pressure adjustment controller, a feedback control system based on an FPGA is designed, and a closed-loop electromechanical control system is used for enabling the outlet pressure of a poppet valve to reach a required set value.

The pressure regulating controller 2 is connected with the pneumatic impact calibration device 1 through an air circuit and an electric signal respectively, and provides compressed gas and pressure control and display for the pneumatic impact calibration device 1.

The automatic pressure regulating controller 3 is connected with the pressure regulating controller 2 through a BNC interface and is used for collecting pressure signals, sending trigger signals and sending motor control signals; the pressure setting device is connected with a computer through a USB and is mainly used for the computer to send out pressure setting signals.

The automatic voltage regulating controller 3 internally comprises an FPGA data processing circuit, a data acquisition circuit A/D, a digital-to-analog conversion circuit D/A1, a digital-to-analog conversion circuit D/A2 and a motor control circuit, wherein the data acquisition circuit A/D is connected with the FPGA data processing circuit, the FPGA data processing circuit is respectively connected with the digital-to-analog conversion circuit D/A1 and the digital-to-analog conversion circuit D/A2, and the digital-to-analog conversion circuit D/A1 is connected with the motor control circuit and used for controlling the motor rotating mechanism to work.

The control panel of the pressure regulating controller 2 is provided with an air source switch 201, a pressure regulating mechanism 202, a pressure display panel 203 and an indicator lamp 204; the pressure adjusting mechanism 202 comprises an electric rotating head 2021, an adjusting knob 2022 and a mounting bracket, the adjusting knob 2022 is arranged on the pressure adjusting controller 2, the electric rotating head 2021 is in transmission connection with the adjusting knob 2022, and the electric rotating head 2021 is fixed on the shell of the pressure adjusting controller 2 through the mounting bracket.

In order to better realize the technical scheme of the utility model, the utility model provides two mounting brackets, wherein one mounting bracket adopts a U-shaped bracket 2023, one end of the U-shaped bracket 2023 is arranged on a connecting column of a shell of the pressure regulating controller 2 through a nut 2024, and the other end of the U-shaped bracket is connected with an electric rotating head 2021 (the electric rotating head is provided with the nut). Another mounting bracket adopts a cylinder bracket 2025, a group of threaded holes are arranged at two ends of the cylinder bracket 2025 along the circumferential direction, one end of the cylinder bracket 2025 is arranged on a connecting column of a shell of the pressure regulating controller 2 through jackscrews, and the other end of the cylinder bracket 2025 is connected with the electric rotating head 2021 through jackscrews.

The implementation process comprises the following steps:

the outlet pressure of the lift valve is collected by a data collection circuit A/D and is transmitted to a programmable gate array FPGA after analog-digital conversion, the FPGA compares the measured pressure with the set pressure, and outputs a direction and a periodic signal for motor control after feedback (such as proportional-integral-derivative (PID)) operation, and the direction and the periodic signal are overlapped with a motor control signal generated by the FPGA and are output to a digital-analog conversion circuit D/A1, and the motor rotating mechanism is controlled to work after the motor control circuit amplifies and the like, so that the aim of controlling the pressure regulator is achieved. The flow is reciprocated until the outlet pressure of the lifting valve is regulated to a set value, at the moment, the FPGA generates a trigger signal and outputs the trigger signal to the D/A conversion circuit D/A2, the lifting valve is controlled to release compressed gas for impact calibration, and the FPGA is connected with a computer through a USB and is used for receiving a pressure set value instruction; for more concise and clear man-machine interaction, the upper computer software is compiled by a high-level graphic language LABVIEW.

Claims

1. The piezoelectric accelerometer automatic calibration system based on the FPGA is characterized by comprising a pneumatic impact calibration device (1), a pressure regulating controller (2), an automatic pressure regulating controller (3) and a computer (4), wherein the pressure regulating controller (2) is connected with the pneumatic impact calibration device (1) through an air circuit and an electric signal respectively to provide compressed air and pressure control and display for the pneumatic impact calibration device (1); the automatic pressure regulating controller (3) is connected with the pressure regulating controller (2) through an electric signal and is used for collecting pressure signals, sending trigger signals and motor control signals; the pressure regulating controller (2) and the automatic pressure regulating controller (3) are respectively connected with the computer (4) through electrical signals.

2. The automatic calibration system of the piezoelectric accelerometer based on the FPGA according to claim 1, wherein the automatic voltage regulation controller (3) comprises an FPGA data processing circuit, a data acquisition circuit A/D, a digital-to-analog conversion circuit D/A1, a digital-to-analog conversion circuit D/A2 and a motor control circuit, the data acquisition circuit A/D is connected with the FPGA data processing circuit, the FPGA data processing circuit is respectively connected with the digital-to-analog conversion circuit D/A1 and the digital-to-analog conversion circuit D/A2, the digital-to-analog conversion circuit D/A1 is connected with the motor control circuit and is used for controlling the motor rotating mechanism to work, and the digital-to-analog conversion circuit D/A2 is used for controlling a trigger signal.

3. The automatic calibration system of the piezoelectric accelerometer based on the FPGA according to claim 1, wherein an air source switch (201), a pressure regulating mechanism (202), a pressure display panel (203) and an indicator lamp (204) are arranged on the pressure regulating controller (2), the pressure regulating mechanism (202) comprises an electric rotating head (2021), an adjusting knob (2022) and a mounting bracket, the adjusting knob (2022) is arranged on the pressure regulating controller (2) and connected with an internal valve of the pressure regulating controller, the electric rotating head (2021) is in transmission connection with the adjusting knob (2022), and the electric rotating head (2021) is fixed on a shell of the pressure regulating controller (2) through the mounting bracket.

4. The automatic calibration system of the piezoelectric accelerometer based on the FPGA according to claim 3, wherein the mounting bracket is a U-shaped bracket (2023), one end of the U-shaped bracket (2023) is mounted on a connecting column of a shell of the pressure regulating controller (2) through a nut (2024), and the other end of the U-shaped bracket is connected with the electric rotating head (2021).

5. The automatic calibration system of the piezoelectric accelerometer based on the FPGA according to claim 3, wherein the mounting bracket adopts a cylindrical bracket (2025), two ends of the cylindrical bracket (2025) are respectively provided with a group of threaded holes along the circumferential direction, one end of the cylindrical bracket (2025) is mounted on a connecting column of a shell of the pressure regulating controller (2) through a jackscrew, and the other end of the cylindrical bracket is connected with the electric rotating head (2021) through the jackscrew.