CN-121995440-A - Low-noise seismometer feedback system and device

CN121995440ACN 121995440 ACN121995440 ACN 121995440ACN-121995440-A

Abstract

The invention discloses a low-noise seismometer feedback system and a device, which relate to the field of seismic observation, wherein a feedback system is formed by an analog and digital dual-PID feedback network and a parameter correction network, a high-frequency cut-off frequency is realized by an analog PID network, a digital PID plays a role in fine adjustment of parameters, so that quick response to a high-frequency signal is realized, a low-frequency cut-off frequency is realized by the combination of the analog PID and the digital PID, proper analog PID parameters are selected according to different low-frequency cut-off frequencies, and then a low-frequency cut-off period is spread by the digital PID. The MCU is used for controlling the DAC to output calibration signals, the digital PID parameters are dynamically regulated by combining the output voltage acquired by the ADC, the automatic calibration of the seismometer parameters is realized, the consistency of amplitude-frequency characteristics of different seismometers is ensured, and the labor production cost is reduced. The invention can realize a low-noise and high-performance seismometer feedback system and improve the detection capability of the seismometer on tiny signals.

Inventors

KANG LULU
NIU LINGHUI
ZHAO ZIHAO
LIU MINGHUI
DA SHUAI
Zhou yinxing
ZHU XIAOYI
WU WEIYUAN

Assignees

北京港震科技股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260227

Claims (7)

1. The low-noise seismometer feedback system is characterized by comprising an analog PID feedback network, a digital PID feedback network and a parameter correction network, wherein the analog PID feedback network and the digital PID feedback network are connected in parallel and then connected to a feedback coil of the force balance seismometer, and the parameter correction network is linked with the analog PID feedback network and the digital PID feedback network and is used for automatically adjusting parameters of the digital PID feedback network.
2. The low noise seismometer feedback system of claim 1, wherein the analog PID feedback network comprises a proportional resistor R 1,a , a differential capacitor C 1,a and an integrating network, the integrating network comprises an integrating resistor R 2,a , an integrating capacitor C 2,a and an integrating output resistor R 3,a , the proportional resistor R 1,a , the differential capacitor C 1,a and the integrating network are connected in parallel, an integral common input is connected with a voltage signal output by a displacement transducer, and a common output is connected with a feedback coil of the seismometer.
3. The low noise seismometer feedback system of claim 2, wherein said digital PID feedback network comprises an ADC, an MCU, a digital PID algorithm module, a DAC and a constant voltage to constant current circuit connected in sequence.
4. A low noise seismometer feedback system according to claim 3, characterized in that said digital PID algorithm module is calculated on the principle of: in the formula, Is a low frequency cut-off period; sampling period for ADC; Is a high frequency cut-off frequency; The proportional resistance is an analog part; Is an analog differential capacitance; Collecting a voltage value for an ADC at a time t; And collecting a voltage value for the ADC at the time t-1.
5. The low noise seismometer feedback system of claim 1, wherein the parameter correction network comprises a DAC, a calibration resistor R10, and a calibration coil electromagnetically coupled to the feedback coil, the DAC, the calibration resistor R10, and the calibration coil are sequentially connected in series, and the DAC, the ADC, and the MCU are electrically connected.
6. The low noise seismometer feedback system of claim 1, wherein the analog PID feedback network is designed according to a seismometer target low frequency cut-off period, wherein the analog PID feedback network is designed according to a 2s low frequency cut-off period when the target low frequency cut-off period is 60s, and the analog PID feedback network is designed according to a 60s low frequency cut-off period when the target low frequency cut-off period is 120s or 360 s.
7. A low noise seismometer feedback device based on a low noise seismometer feedback system according to any one of claims 1-6, characterized in that it comprises a force balance seismometer body and a low noise seismometer feedback system, said force balance seismometer body comprises a mechanical pendulum body, a displacement transducer, a feedback coil and a magnetic system, said displacement transducer is connected with the mechanical pendulum body, an analog PID feedback network, a digital PID feedback network, respectively, and the feedback coil of said low noise seismometer feedback system is connected into the magnetic system of the force balance seismometer body.

Description

Low-noise seismometer feedback system and device Technical Field The invention relates to the technical field of seismic observation, in particular to a low-noise seismometer feedback system and a low-noise seismometer feedback device. Background At present, the force balance seismometer is a core sensor for earthquake monitoring, is widely applied to a seismic monitoring and observing system in China, and adopts a mechanical pendulum body and hardware circuit simulation PID feedback electromechanical integrated feedback technology to realize long-period and low-noise earthquake signal monitoring. The traditional force balance seismometer consists of a mechanical pendulum body, a displacement transducer, a feedback network, a feedback coil and a magnetic system, wherein the displacement transducer converts the earth movement acceleration detected by the mechanical pendulum body into a voltage signal, then the voltage signal is converted into a current signal through the feedback network, and the feedback coil and the magnetic system generate electromagnetic force by utilizing the current signal to prevent the relative movement of a pendulum of the mechanical pendulum body. The dynamic range of the digital PID feedback is far lower than 240dB of the analog PID feedback due to the technical development limitation of the ADC and the DAC, and even if the 32-bit ADC and the 20-bit DAC are exposed, the dynamic range of the digital PID feedback is only 140dB at most, so that the force balance seismometer on the market basically adopts a pure analog PID feedback scheme. However, with the requirements of deep observation of the earth planned by the state, the application of the very wide-band force balance seismometer with the low-frequency cut-off period ranging from 360s is more and more extensive, and the lower the low-frequency cut-off frequency of the seismometer is, the larger the resistance and capacitance parameters required by the feedback network are, the larger the resistance and the larger capacitance can introduce extremely large thermal noise, so that the noise of the seismometer is increased. In addition, because of the machining difference of the mechanical pendulum body and the precision error of electronic components, in order to ensure the consistency of the low-frequency cut-off period, the damping, the high-frequency cut-off frequency and the damping of different seismometers, each force balance seismometer needs to independently adjust feedback parameters, and the process is time-consuming and labor-consuming, so that the production cost is greatly increased. In summary, the existing force balance seismometer has two main core problems that the noise of pure analog PID feedback is high in an ultra-wideband scene, the dynamic range of pure digital PID feedback is insufficient, the noise and the wide dynamic range are difficult to be considered, and the feedback parameters are required to be adjusted manually and independently, so that the production cost is high and the parameter consistency is poor. Therefore, how to solve the problems of large thermal noise of pure analog PID feedback and insufficient dynamic range of pure digital PID feedback, and simultaneously realize automatic adjustment of the feedback parameters of seismometers, ensure the consistency of parameters of different seismometers, and reduce the production cost is a problem which needs to be solved by the technicians in the field. Disclosure of Invention In view of the foregoing, the present invention provides a low noise seismometer feedback system and apparatus to solve the problems in the background art. In order to achieve the above purpose, the present invention adopts the following technical scheme: The utility model provides a low noise seismometer feedback system, includes analog PID feedback network, digital PID feedback network and parameter correction network, the feedback coil of force balance seismometer is connected to after analog PID feedback network and digital PID feedback network are parallelly connected, parameter correction network links with analog PID feedback network, digital PID feedback network for automatically regulated digital PID feedback network's parameter. Optionally, the analog PID feedback network comprises a proportional resistor R 1,a, a differential capacitor C 1,a and an integral network, the integral network comprises an integral resistor R 2,a, an integral capacitor C 2,a and an integral output resistor R 3,a, the proportional resistor R 1,a, the differential capacitor C 1,a and the integral network are connected in parallel, the integral common input end is connected with a voltage signal output by the displacement transducer, and the common output end is connected with a feedback coil of the seismometer. Optionally, the digital PID feedback network comprises an ADC, an MCU, a digital PID algorithm module, a DAC and a constant voltage-to-constant current circuit which are sequentially