Method for using accelerometer of high-precision inclinometer

Abstract

The invention relates to the technical field of inclinometers, in particular to an accelerometer using method of a high-precision inclinometer, which comprises the technical means of dynamic sampling frequency adjustment, multi-stage filtering architecture, dual-channel redundancy check, temperature compensation and the like. The signal acquisition and processing flow is optimized through combination of hardware and software, and the measurement precision and the anti-interference capability are remarkably improved. According to the invention, the problem of measurement errors caused by vibration, noise and temperature change in an underground complex environment can be effectively solved, the stability and adaptability of the system are enhanced, and a reliable guarantee is provided for the application of the inclinometer in high-precision detection.

Description

Technical Field

[0001] The present invention relates to the technical field of inclinometers and accelerometer applications, and in particular to a method for using an accelerometer of a high-precision inclinometer. Background Art

[0002] With the widespread use of inclinometers in downhole exploration, the demand for high-precision measurements is increasing. Existing inclinometers use a combination of multiple sensors to measure well depth and attitude angles, but the use of accelerometers still has certain limitations, affecting measurement accuracy, stability, and adaptability.

[0003] After searching, an electronic inclinometer capable of measuring well depth and a method for measuring well depth were disclosed with publication number CN105317423B, and the publication date is December 13, 2022. This patent realizes real-time measurement of the attitude angle and acceleration of the well trajectory and can directly record the well depth by integrating a three-axis magnetic sensor, a three-axis gyroscope sensor and a three-axis acceleration sensor in the probe short section of the electronic inclinometer. However, in this technical solution, the use method of the accelerometer mainly relies on data fusion with other sensors, and lacks an optimized design for the measurement characteristics of the accelerometer itself. Under complex working conditions, the measurement accuracy may decrease. In addition, the solution has limited consideration of anti-interference capabilities, especially in high-vibration or strong interference environments, the reliability and stability of the data may be affected to a certain extent.

[0004] The above issues demonstrate that existing inclinometers have shortcomings in their accelerometer usage, particularly in adaptability and anti-interference capabilities for high-precision measurements. Therefore, the present invention provides a method for using an accelerometer in a high-precision inclinometer. This method aims to improve measurement accuracy and stability by optimizing the accelerometer's signal processing algorithm and anti-interference design, thereby meeting the high-precision measurement requirements under complex working conditions. Summary of the Invention

[0005] This invention provides a method for using an accelerometer in a high-precision inclinometer. It aims to overcome the existing issues of reduced measurement accuracy and stability caused by inadequate signal processing algorithms and lack of anti-interference design. By improving the data acquisition and processing process and optimizing the design's adaptability to complex environments, this invention can significantly enhance the performance of inclinometers in downhole exploration.

[0006] To achieve the above objectives, the present invention proposes a data processing method based on a dynamic compensation mechanism. Specifically, in the signal acquisition stage of the accelerometer, a segmented sampling frequency adjustment strategy is adopted. According to the changing characteristics of the downhole environment, the sampling frequency is dynamically adjusted to match the vibration intensity and interference level under different working conditions. For example, in a low-vibration environment, the sampling frequency can be set to a lower value to reduce data redundancy; in a high-vibration or strong interference environment, it automatically switches to a high-frequency sampling mode to capture more subtle dynamic changes. This frequency adjustment strategy is implemented through a frequency control module in the hardware circuit, which contains a programmable clock generator and a set of logic gate circuits for real-time control of the sampling period.

[0007] Furthermore, the present invention introduces a multi-stage filtering architecture for optimizing the quality of the accelerometer output signal. The first stage of filtering uses a hardware-implemented analog low-pass filter, whose cutoff frequency is pre-set according to the range of the accelerometer to remove high-frequency noise. The second stage of filtering is completed by a digital signal processing unit, and the collected acceleration signal is post-processed using an adaptive Kalman filter algorithm. The algorithm combines real-time environmental parameter estimation and gradually approaches the true signal value by recursively updating the state prediction value and covariance matrix. It is worth noting that the initial parameters of the Kalman filter are determined through offline calibration experiments and stored in non-volatile memory for actual operation.

[0008] In response to the problem of insufficient anti-interference ability under complex working conditions, the present invention designs a signal verification mechanism based on dual-channel redundant verification. The output signal of the accelerometer is simultaneously transmitted to two independent signal processing channels, each channel is equipped with an independent analog-to-digital converter and signal conditioning circuit. After the two signals undergo the same filtering and processing process, they are compared and analyzed by the central processing unit. If the deviation of the two signals exceeds the preset threshold, it is determined that there is strong interference in the current environment, and the system will start the backup signal source and recalibrate the reference value. The redundant verification mechanism is implemented through a double-layer wiring structure on the circuit board, in which each signal path is wrapped with a shielding layer and isolated by a ground plane to reduce the impact of electromagnetic interference.

[0009] In addition, the present invention also proposes a zero-drift correction method based on temperature compensation. Due to the large fluctuations in the ambient temperature downhole, the zero-drift of the accelerometer can significantly affect the measurement results. To this end, a set of micro-thermistors is embedded in the accelerometer housing to monitor ambient temperature changes in real time. The output signal of the thermistor is amplified and input into a microcontroller, which performs linear compensation on the original output of the accelerometer based on a preset temperature-zero-drift relationship curve. This compensation curve is obtained through laboratory calibration and covers the entire temperature range from low to high temperatures, ensuring that zero-drift can be effectively suppressed throughout the entire operating temperature range.

[0010] To further improve the stability and reliability of the system, the present invention also designs a modular installation structure. The accelerometer and its related circuit components are encapsulated in an independent functional module, which is fixed to the main frame of the inclinometer via a threaded connection. A flexible circuit board is used inside the module to connect the various electronic components to reduce the impact of mechanical stress on signal transmission. At the same time, the module housing is made of high-strength aluminum alloy material and coated with a conductive shielding coating on the surface to enhance the ability to resist electromagnetic interference. The electrical connection between the module and the main frame is achieved through a plug-in connector, and an anti-loosening mechanism is integrated inside the connector to ensure that a stable electrical connection can be maintained even in a strong vibration environment.

[0011] In practical applications, the aforementioned technical approaches work together to improve the accelerometer's measurement performance in complex downhole environments. The dynamic sampling frequency adjustment strategy enables the system to flexibly respond to different operating conditions, avoiding the data redundancy or information loss problems caused by traditional fixed sampling frequencies. The multi-stage filtering architecture effectively removes various types of noise interference and improves signal purity through a combination of hardware and software. The dual-channel redundant verification mechanism significantly enhances the system's anti-interference capabilities, ensuring data reliability even in extreme environments. The temperature compensation method addresses the characteristics of downhole temperature fluctuations, fundamentally solving the zero-point drift problem and significantly improving measurement accuracy.

[0012] In summary, the present invention addresses numerous deficiencies in the prior art by comprehensively optimizing accelerometer signal acquisition, processing, verification, and installation. Innovative designs, including a dynamic sampling frequency adjustment strategy, a multi-stage filtering architecture, a dual-channel redundant verification mechanism, and a temperature compensation method, not only significantly improve the inclinometer's measurement accuracy and stability, but also enhance its adaptability to complex operating conditions. The specific implementations of these technical approaches have been carefully designed and verified to ensure that those skilled in the art can accurately replicate the present invention's technical solutions based on the descriptions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the system structure of the method for using the accelerometer of the high-precision inclinometer in an embodiment of the present invention.

[0014] In the figure: 1. Accelerometer; 2. Dynamic sampling frequency adjustment module; 3. Analog low-pass filter; 4. Digital signal processing unit; 5. Dual-channel signal processing path; 6. Temperature compensation module; 7. Thermistor; 8. Central processing unit; 9. Modular packaging structure. DETAILED DESCRIPTION

[0015] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] The present invention provides a method for using an accelerometer of a high-precision inclinometer. Figure 1 The system structure diagram shown in the figure describes its implementation process in detail. Figure 1 The figure shows the specific components and connections of the accelerometer 1, dynamic sampling frequency adjustment module 2, analog low-pass filter 3, digital signal processing unit 4, dual-channel signal processing path 5, temperature compensation module 6, thermistor 7, central processing unit 8, and modular packaging structure 9. The following describes the connection method, positional relationship, and specific implementation of the interaction of each component according to the system operation process.

[0017] In practical applications, the accelerometer 1 serves as the core sensing element and is installed in the center of the modular packaging structure 9. The modular packaging structure 9 is made of high-strength aluminum alloy and is internally connected to the accelerometer 1 via a flexible printed circuit board, minimizing the impact of mechanical stress on signal transmission. One end of the flexible printed circuit board is welded to the signal output of the accelerometer 1, while the other end extends to the edge of the modular packaging structure 9 and connects to the input of the dynamic sampling frequency adjustment module 2. The dynamic sampling frequency adjustment module 2 includes a programmable clock generator and a set of logic gate circuits. These components are electrically connected via wires on the printed circuit board and form a communication link with the signal output of the accelerometer 1 via a hardware interface.

[0018] The dynamic sampling frequency adjustment module 2 operates by adjusting the sampling period in real time based on the changing characteristics of the downhole environment. Specifically, when downhole vibration intensity is low, the logic gate circuit reduces the sampling frequency by lowering the output frequency of the programmable clock generator, thereby avoiding data redundancy. In high-vibration or strong interference environments, the logic gate circuit automatically switches to high-frequency mode, increasing the sampling frequency to capture more subtle dynamic changes. This frequency adjustment strategy is implemented by a frequency control module in the hardware circuit. The output signal of the programmable clock generator directly acts on the analog-to-digital converter of accelerometer 1 to control its sampling rate. The output signal of the dynamic sampling frequency adjustment module 2 is then transmitted to the input of the analog low-pass filter 3.

[0019] The analog low-pass filter 3 is located after the dynamic sampling frequency adjustment module 2. Its primary function is to remove high-frequency noise. It consists of resistors, capacitors, and an operational amplifier. These components are soldered to a printed circuit board and connected to the output of the dynamic sampling frequency adjustment module 2 via wires. The cutoff frequency of the analog low-pass filter 3 is pre-set based on the measuring range of the accelerometer 1, typically at 1.5 times the upper frequency limit of the accelerometer 1 to effectively filter out high-frequency interference outside the measuring range. The signal processed by the analog low-pass filter 3 is then transmitted to the input of the digital signal processing unit 4.

[0020] The digital signal processing unit 4 is located after the analog low-pass filter 3. Its core part is an embedded microprocessor, which is connected to the memory and input and output interfaces via a bus. The main function of the digital signal processing unit 4 is to post-process the collected acceleration signal using an adaptive Kalman filter algorithm. The initial parameters of the Kalman filter algorithm are determined through offline calibration experiments and stored in a non-volatile memory. During actual operation, the digital signal processing unit 4 recursively updates the state prediction value and covariance matrix based on the real-time environmental parameter estimation, gradually approximating the true signal value. The output signal of the digital signal processing unit 4 is then transmitted to the two independent channels of the dual-channel signal processing path 5.

[0021] The dual-channel signal processing path 5 consists of two independent analog-to-digital converters and signal conditioning circuits. Each circuit is wrapped in a shielding layer and connected to the ground plane to reduce the impact of electromagnetic interference. The two channels of the dual-channel signal processing path 5 receive the same signal from the digital signal processing unit 4 and perform the same filtering and processing procedures. The output signal of each channel is transmitted to the input end of the central processing unit 8 through a wire, and the central processing unit 8 compares and analyzes the two signals. If the deviation between the two signals exceeds the preset threshold, it is determined that there is strong interference in the current environment. The central processing unit 8 will start the backup signal source and recalibrate the reference value. The design of the dual-channel signal processing path 5 ensures the reliability of the data even in extreme environments.

[0022] The temperature compensation module 6 is located within the housing of the accelerometer 1. Its core component is a set of miniature thermistors 7. These are connected to the signal input of the temperature compensation module 6 via wires, while the output of the module is connected to the input of a central processing unit 8 via wires. The output signal of the thermistors 7 is amplified and fed into a microcontroller, which applies linear compensation to the raw output of the accelerometer 1 based on a preset temperature-zero drift curve. The design of the temperature compensation module 6 addresses the significant temperature fluctuations found underground, fundamentally resolving the zero drift problem.

[0023] The design of the modular packaging structure 9 further enhances the system's stability and reliability. It is secured to the inclinometer's main frame via threaded connections and coated with a conductive shielding coating to enhance resistance to electromagnetic interference. The electrical connection between the modular packaging structure 9 and the main frame is established via a plug-in connector with an integrated anti-loosening mechanism, ensuring a stable electrical connection even in high-vibration environments.

[0024] In practical applications, the above-mentioned technical means work together to improve the measurement performance of the accelerometer in complex downhole environments. The dynamic sampling frequency adjustment module 2 enables the system to respond flexibly to different working conditions, avoiding the data redundancy or information loss caused by the traditional fixed sampling frequency. The analog low-pass filter 3 and the digital signal processing unit 4 effectively remove various types of noise interference and improve the purity of the signal through a combination of hardware and software. The dual-channel signal processing path 5 significantly enhances the system's anti-interference ability and can ensure data reliability even in extreme environments. The temperature compensation module 6 fundamentally solves the zero drift problem based on the characteristics of downhole temperature fluctuations, thereby greatly improving measurement accuracy.

[0025] In order to better enable relevant personnel in this technical field to fully understand and implement the present invention, the specific implementation principle of the present invention is supplemented below with reference to a specific application scenario.

[0026] Before lowering the inclinometer downhole, the operator must install the accelerometer 1 in the center of the modular packaging structure 9 and connect it to the dynamic sampling frequency adjustment module 2 via a flexible printed circuit board. The modular packaging structure 9 is constructed from high-strength aluminum alloy, and its internal design minimizes the impact of mechanical stress on signal transmission. One end of the flexible printed circuit board is soldered to the signal output terminal of the accelerometer 1, while the other end extends to the edge of the modular packaging structure 9 and connects to the input terminal of the dynamic sampling frequency adjustment module 2. The programmable clock generator and logic gate circuit in the dynamic sampling frequency adjustment module 2 are electrically connected via wires on the printed circuit board, forming a communication link. In actual operation, once the inclinometer is in the downhole environment, the dynamic sampling frequency adjustment module 2 adjusts the sampling period in real time based on changes in downhole vibration intensity. If downhole vibration is weak, the logic gate circuit reduces the output frequency of the programmable clock generator, thereby reducing the sampling frequency to avoid data redundancy. In environments with high vibration or strong interference, the logic gate circuit switches to high-frequency mode, increasing the sampling frequency to capture more subtle dynamic changes. This segmented sampling frequency adjustment strategy is implemented by a frequency control module in the hardware circuit, wherein the output signal of the programmable clock generator directly acts on the analog-to-digital converter of the accelerometer 1, thereby controlling its sampling rate.

[0027] The signal collected by the accelerometer 1 is then transmitted to the analog low-pass filter 3 for processing. This filter consists of resistors, capacitors, and an operational amplifier, soldered to a printed circuit board (PCB) and connected to the output of the dynamic sampling frequency adjustment module 2. The cutoff frequency of the filter is pre-set based on the measuring range of the accelerometer 1, typically 1.5 times the upper frequency limit, to effectively filter out high-frequency noise that exceeds the measuring range. The signal processed by the filter is then transmitted to the digital signal processing unit 4. The core of the digital signal processing unit 4 is an embedded microprocessor connected to memory and input / output interfaces via a bus. During actual operation, the digital signal processing unit 4 uses an adaptive Kalman filter algorithm to post-process the collected acceleration signal. The initial parameters of the Kalman filter algorithm are determined through offline calibration experiments and stored in non-volatile memory. During operation, the digital signal processing unit 4 recursively updates the state prediction value and covariance matrix based on real-time environmental parameter estimates, gradually approximating the true signal value and thus further improving signal purity.

[0028] Next, the signal processed by the digital signal processing unit 4 is transmitted to the dual-channel signal processing path 5. The dual-channel signal processing path 5 consists of two independent analog-to-digital converters and signal conditioning circuits. Each circuit is wrapped by a shielding layer and connected to the ground plane to reduce the impact of electromagnetic interference. The two channels of the dual-channel signal processing path 5 receive the same signal from the digital signal processing unit 4 and perform the same filtering and processing procedures. The output signal of each channel is transmitted to the input end of the central processing unit 8 through a wire, and the central processing unit 8 compares and analyzes the two signals. If the deviation between the two signals exceeds the preset threshold, it is determined that there is strong interference in the current environment. The central processing unit 8 will start the backup signal source and recalibrate the reference value. For example, in a certain underground detection, due to strong external electromagnetic interference, the dual-channel signal processing path 5 detects that the deviation between the two signals exceeds the normal range. At this time, the central processing unit 8 automatically switches to the backup signal source and recalibrates the reference value to ensure the reliability of the data.

[0029] At the same time, the temperature compensation module 6 monitors changes in the downhole ambient temperature in real time and compensates the output signal of the accelerometer 1. The temperature compensation module 6 is located inside the housing of the accelerometer 1, and its core component is a group of miniature thermistors 7. The thermistors 7 are connected to the signal input terminal of the temperature compensation module 6 via wires, and their output signals are amplified and input to the microcontroller. The microcontroller performs linear compensation on the original output of the accelerometer 1 based on a preset temperature-zero drift relationship curve. For example, as the downhole temperature rises from 20°C to 80°C, the temperature compensation module 6 adjusts the output signal of the accelerometer 1 in real time based on the temperature changes monitored by the thermistors 7, thereby eliminating the zero drift problem caused by temperature fluctuations.

[0030] Finally, the design of the modular packaging structure 9 further improves the stability and reliability of the system. The modular packaging structure 9 is fixed to the main frame of the inclinometer through a threaded connection, and its surface is coated with a conductive shielding coating to enhance its anti-electromagnetic interference capability. The electrical connection between the modular packaging structure 9 and the main frame is achieved through a plug-in connector, and an anti-loosening mechanism is integrated inside the connector to ensure that a stable electrical connection can be maintained even in a strong vibration environment. For example, during a certain underground operation, due to the strong vibration of the drilling equipment, the modular packaging structure 9 effectively reduced the impact of mechanical stress on signal transmission through its internal flexible circuit board and external high-strength aluminum alloy material. At the same time, the anti-loosening mechanism of the plug-in connector ensures the stability of the electrical connection.

[0031] In summary, the above-mentioned technical means work synergistically in practical applications to jointly improve the measurement performance of the accelerometer in complex downhole environments. The dynamic sampling frequency adjustment module 2 enables the system to respond flexibly under different working conditions, avoiding the data redundancy or information loss problems caused by the traditional fixed sampling frequency. The analog low-pass filter 3 and the digital signal processing unit 4 effectively remove various types of noise interference and improve the purity of the signal by combining hardware and software. The dual-channel signal processing path 5 significantly enhances the system's anti-interference ability and can ensure data reliability even in extreme environments. The temperature compensation module 6 fundamentally solves the zero drift problem based on the characteristics of downhole temperature fluctuations, thereby greatly improving the measurement accuracy. The contents not described in detail in the specification belong to the existing technology known to those skilled in the art, and the model parameters of each electrical appliance are not specifically limited, and conventional equipment can be used. In this technical solution, the electrical control components not mentioned are not shown in the figure because they belong to the existing technology and are not described here.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0033] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for using an accelerometer of a high-precision inclinometer, characterized in that The following steps are involved: The sampling frequency of the accelerometer (1) is adjusted in real time according to the change of the vibration intensity of the downhole environment through the dynamic sampling frequency adjustment module (2); The signal output by the accelerometer (1) is transmitted to an analog low-pass filter (3) to remove high-frequency noise; The signal processed by the analog low-pass filter (3) is input into the digital signal processing unit (4), and the signal is post-processed using an adaptive Kalman filter algorithm; The processed signals are transmitted to two independent channels of the dual-channel signal processing path (5), and the central processing unit (8) compares and analyzes the two signals, and activates the backup signal source and recalibrates the reference value when the deviation exceeds a preset threshold; The temperature compensation module (6) linearly compensates the zero drift of the accelerometer (1) according to the change of the ambient temperature monitored by the thermistor (7).

2. The method for using the accelerometer of the high-precision inclinometer according to claim 1, characterized in that: The dynamic sampling frequency adjustment module (2) includes a programmable clock generator and a logic gate circuit. The logic gate circuit adjusts the output frequency of the programmable clock generator according to the change of the vibration intensity of the underground environment to control the sampling period of the accelerometer (1).

3. The method for using the accelerometer of the high-precision inclinometer according to claim 1, characterized in that: The analog low-pass filter (3) is composed of a resistor, a capacitor and an operational amplifier, and its cut-off frequency is set to 1.5 times the upper limit frequency of the accelerometer (1).

4. The method for using the accelerometer of the high-precision inclinometer according to claim 1, characterized in that: The modular packaging structure (9) is made of high-strength aluminum alloy material, and is internally connected to the accelerometer (1) and related circuit components through a flexible circuit board. The modular packaging structure (9) is electrically connected to the main frame of the inclinometer through a plug-in connector, and an anti-loosening mechanism is integrated inside the connector.

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