A high-precision fully automated oil film detection method and oil film instrument

Abstract

A high-precision, fully automated oil film detection method and oil film instrument include: allowing the oil film to be detected to float on a substrate, pushing the oil film to be detected by an oil film pushing mechanism, measuring the voltage value between the oil film to be detected and the substrate during the pushing process by a measuring device, and obtaining the position of the oil film pushing mechanism during the pushing process; using the distance between the position of the oil film pushing mechanism and a predetermined end point as the torque of the oil film pushing mechanism; determining a target relationship between the voltage value and the torque based on the voltage value and the torque during the pushing process; when the voltage value reaches a preset value, using the voltage value as the target voltage value, obtaining the torque corresponding to the target voltage value as the target torque through the target relationship, and determining the oil volume of the oil film to be detected based on the target voltage value and the target torque. The present invention can fully automatically, efficiently, and quickly measure the oil volume of the oil film, making the oil film measurement process intelligent, using step characteristics to determine the coefficient of the oil volume formula, and improving the accuracy of oil film detection.

Description

Technical Field

[0001] The present invention relates to the technical field of oil film and oil quantity detection, and in particular to a high-precision fully-automatic oil film detection method and an oil film instrument. Background Art

[0002] In the field of industrial oil film detection, existing technologies have the following technical bottlenecks:

[0003] Traditional testing equipment mostly uses outdated operating systems with limited compatibility, making it difficult to support modern data processing algorithms and interactive interface designs; motion control systems generally use open-loop stepping structures, which have insufficient positioning accuracy and stability, restricting the accuracy of test results; software systems lack adaptive data processing capabilities, have low flexibility in responding to diverse testing needs, and lack intelligence.

[0004] Therefore, there is an urgent need for a new oil film detection solution that integrates advanced hardware architecture, intelligent control algorithms and efficient software systems to break through the limitations of existing technologies. Summary of the Invention

[0005] In order to overcome the above-mentioned defects, the present invention proposes a high-precision fully-automated oil film detection method and an oil film instrument to solve the problems of inaccurate oil film detection results and insufficient intelligence of the detection process.

[0006] The present invention provides a high-precision fully automated oil film detection method, comprising the following steps:

[0007] S1, making the oil film to be tested float on the substrate, pushing the oil film to be tested by the oil film pushing mechanism, measuring the voltage value between the oil film to be tested and the substrate during the pushing process by a measuring device, and obtaining the position of the oil film pushing mechanism during the pushing process;

[0008] S2, taking the distance between the position of the oil film pushing mechanism and the predetermined end point as the torque of the oil film pushing mechanism; determining the target relationship between the voltage value and the torque according to the voltage value and the torque during the pushing process;

[0009] S3, when the voltage value reaches the preset value, the voltage value is used as the target voltage value, the torque corresponding to the target voltage value is obtained as the target torque through the target relationship, and the oil amount of the oil film to be detected is determined according to the target voltage value and the target torque.

[0010] A further improvement of the present invention is that the oil film pushing mechanism is driven by a servo motor, and the servo motor corrects the position of the oil film pushing mechanism according to a PID algorithm.

[0011] A further improvement of the present invention is that, before determining the target relationship between the voltage value and the torque according to the voltage value and the torque during the pushing process, the present invention further includes:

[0012] The voltage value during the driving process is filtered using the spectral threshold method.

[0013] A further improvement of the present invention is to determine the oil volume of the oil film to be detected according to the target voltage value and the target torque, specifically:

[0014] ;

[0015] in, is the amount of oil in the oil film to be tested, 、 is the coefficient, is the target torque.

[0016] A further improvement of the present invention is to determine 、 The process is as follows:

[0017] An oil film with a known amount of oil is floated on a substrate, and an oil film pushing mechanism is used to push the oil film. The surface tension of the oil film during the pushing process, the position of the oil film pushing mechanism, and the time of data collection are collected. The correlation between tension and position is determined based on the time of each data collection and its corresponding surface tension of the oil film and the position of the oil film pushing mechanism.

[0018] The step point of the oil film is determined according to the surface tension and the time of data collection. The time of data collection corresponding to the step point is used as the target time. The position of the oil film pushing mechanism corresponding to the target time is determined according to the correlation between tension and position. The target time is determined according to the position of the oil film pushing mechanism and the known amount of oil. 、 The value of .

[0019] Beneficial effects of the present invention:

[0020] By leveraging the relationship between the torque of the oil film pushing mechanism and the oil film voltage, the present invention can automatically and efficiently measure the oil film volume, making the oil film measurement process intelligent. The coefficient parameters in the oil film volume formula are determined based on the step characteristics of the single-molecule oil film, improving the accuracy of oil film detection. The servo mechanism drives the oil film pushing mechanism, improving the accuracy of the torque and making the oil film detection results more accurate.

[0021] The present invention provides an oil film meter, comprising: a main control unit, a servo system and an intelligent detection unit;

[0022] The main control unit is connected to the servo system for data exchange with the servo system; the main control unit is connected to the intelligent detection unit for data exchange with the intelligent detection unit and calculates the oil volume of the oil film to be detected based on the data collected by the intelligent detection unit;

[0023] The servo system includes a servo motor and a driver. The servo system is used to drive the oil film pushing mechanism, which is used to diffuse and gather the oil film to be tested.

[0024] The intelligent detection unit includes a data measurement module and an intelligent calibration module. The data measurement module is used to measure the voltage value between the oil film to be detected and the substrate during the pushing process, and the intelligent calibration module is used to calibrate the data measurement module.

[0025] Beneficial effects of the present invention:

[0026] The present invention uses a main control unit to exchange data with the servo system and intelligent detection unit, centralizing detection functions within the main control unit for integrated control. Parameters during the detection process are configured and parameter curves are displayed through the main control unit's user interface, making the detection process intelligent and easy to operate. Building an open detection platform using the main control unit can address the compatibility issues of traditional equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 1 is a curve diagram showing the change of the torque and oil film voltage value of the oil film pushing mechanism according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] A high-precision fully automated oil film detection method of the present invention comprises the following steps:

[0031] S1: The oil to be tested is dripped onto a substrate. The substrate is generally made of a hydrophobic material. In this embodiment, the substrate is an aqueous solution, and the container holding the aqueous solution is a rectangular water tank. The height of the aqueous solution is consistent with the height of the rectangular water tank, ensuring that the rectangular water tank is just full but not overflowing. The oil is dripped into the aqueous solution. Due to its hydrophilicity and insolubility in water, the oil diffuses onto the surface of the aqueous solution to form an oil film. An oil film pusher is located above the rectangular water tank, contacting the aqueous solution and pushing the spreading oil film. Repeated pushing can cause the oil film to diffuse or aggregate. The position of the oil film pusher during the pushing process, as well as the voltage between the aqueous solution and the oil film, is recorded in real time. During this process, due to the insulating properties of oil, when the oil aggregates, the resistance of the oil film increases, and the voltage between the aqueous solution and the oil film decreases. Conversely, when the oil diffuses, the resistance of the oil film decreases, and the voltage between the aqueous solution and the oil film increases.

[0032] The oil film pushing mechanism is driven by a servo motor. During the process of driving the oil film pushing mechanism, a position limit method is usually used for position calibration. An end point or protrusion is set to restrict the position of the oil film pushing mechanism and prevent it from moving. The corresponding position at this time is the position of the oil film pushing mechanism, which can prevent the position of the oil film pushing mechanism from being unstable. In this embodiment, the movement of the oil film pushing mechanism is controlled by a closed-loop servo, which can accurately move the oil film pushing mechanism according to the set instructions. At the same time, the position of the movement according to the instructions is obtained. Combined with PID algorithm control, the position of the oil film pushing mechanism is calibrated according to the instructions of the servo system, and the difference between the two is obtained. The servo system instructions are fine-tuned based on the difference, so that the positioning accuracy of the servo system driving the oil film pushing mechanism is ≤ 0.01mm, and position calibration at the ±0.02mm level can be achieved.

[0033] S2, set the top edge of the rectangular water tank parallel to the oil pushing mechanism as the starting point, and the other parallel top edge as the end point. The straight line distance between the oil pushing mechanism and the end point is used as the torque of the oil pushing mechanism. According to the torque and voltage values ​​during the pushing process, a curve of the change of torque and voltage values ​​is generated, such as Figure 1 As shown, Figure 1 The horizontal axis represents the torque of the oil-pushing mechanism, and the vertical axis represents the voltage value. The oil film undergoes a step state between point A and point B (a step refers to a characteristic of a monomolecular oil film; see the coefficient determination section in S3 for details). It should be noted that the oil-pushing mechanism divides the surface of the rectangular water tank into two areas: one area from the starting point to the oil-pushing mechanism, and the other area from the oil-pushing mechanism to the end point. In this embodiment, the oil film to be detected is located in the area from the starting point to the oil-pushing mechanism.

[0034] When determining the target relationship between the voltage value and the torque during the pushing process, the voltage value during the pushing process is filtered using the spectral threshold method. The process is as follows:

[0035] (1) Perform Fourier transform on the voltage value to convert the correlation between the voltage value and the time of measuring the voltage value from the time domain to the frequency domain, thereby determining the frequency domain spectrum of the voltage value and the time of measuring the voltage value; the Fourier transform formula is as follows:

[0036] ;

[0037] in, is the frequency domain spectrum, is the time relationship between the voltage value and the measured voltage value in the time domain, that is, the time relationship between the voltage value before Fourier transform and the measured voltage value, is the imaginary unit, is the angular frequency, is the base of natural logarithm, is the time at which the voltage is measured. Angular frequency is a fixed parameter in the Fourier transform formula and is calculated based on the sine wave in the Fourier transform.

[0038] (2) Setting a threshold value. In this embodiment, based on experience and demand considerations, the threshold value is set to 38.28 μV.

[0039] (3) The noise filtering formula is as follows:

[0040] ;

[0041] in, is the frequency domain spectrum after threshold processing, is the amplitude of the frequency component in the frequency domain spectrum, Threshold is the threshold value set in (2) (i.e. 38.28μV), For logical judgment, when When it is less than Threshold, the frequency in the frequency domain spectrum is set to 0.

[0042] (4) Convert the processed frequency domain spectrum into the time domain, that is, inverse Fourier transform, the formula is as follows:

[0043] ;

[0044] in, It is the relationship between the voltage value in the time domain after threshold processing and the time of measuring the voltage value.

[0045] The advantage of doing this is that by filtering the voltage values, voltage data exceeding the threshold (38.28 μV) can be removed, thereby effectively reducing the impact of noise voltage values ​​and improving the accuracy of subsequent data processing.

[0046] Therefore, the main purpose of measuring the voltage value in this embodiment is to determine the position of the single-molecule oil film step moment based on the voltage value, and to determine the torque based on the position. The voltage value itself does not participate in the calculation. The preprocessing (filtering) of the voltage value is also to remove noise so that the relationship between the voltage value and the torque is not affected by noise.

[0047] S3, when the voltage reaches the preset value (corresponding to Figure 1 The oil film at point A-point B in the figure undergoes a step state, forming a single-molecule oil film. The voltage values ​​corresponding to points A and B are averaged and calculated as the corresponding voltage value. The oil film corresponding to the preset value is considered to be in the single-molecule oil film state. At this time, the voltage is the target voltage, and the torque corresponding to the target voltage is the target torque. The oil volume to be tested is determined based on the target voltage and target torque. The formula is as follows:

[0048] ;

[0049] in, is the amount of oil in the oil film to be tested, 、 is the coefficient, is the target torque, that is, the straight-line distance between the oil film pushing mechanism and the end point at the target voltage moment.

[0050] Coefficient of determination 、 The process is as follows:

[0051] An oil film with a known amount of oil is floated on a substrate, and an oil film pushing mechanism is used to push the oil film. The surface tension of the oil film during the pushing process, the position of the oil film pushing mechanism, and the time of data collection are collected. Each time data is collected, a set of data about "surface tension of the oil film - position of the oil film pushing mechanism - time of data collection" is obtained. The three correspond to each other, and the correlation between the surface tension, the position of the oil film pushing mechanism, and the time of data collection can be obtained.

[0052] The step point refers to the critical phenomenon caused by a sudden change in the surface tension of a single-molecule oil film due to the step characteristics of the single-molecule oil film during its formation process. The point corresponding to this phenomenon is the step point, and the time corresponding to the step point is the step time.

[0053] Extract the surface tension of the oil film and the time of data collection in the correlation relationship, and determine the step time corresponding to the step point of the known oil amount through the surface tension and the time of data collection according to the step characteristics of the single-molecule oil film during the formation process. Use this step time as the target time for data collection, and find the corresponding position of the oil film pushing mechanism in the correlation relationship as the target position of the oil film pushing mechanism. This target position is the corresponding position of the oil film pushing mechanism when the oil film of known oil amount forms a single-molecule oil film. Repeat the experiment many times, record the target position of the oil film pushing mechanism, and combine it with the known oil amount used in the experiment to calculate the mathematical relationship between the position of the oil film pushing mechanism and the known oil amount. It is also the mathematical relationship between the torque of the oil film pushing mechanism (that is, the straight-line distance between the oil film pushing mechanism and the end point of the rectangular water tank) and the known oil amount, and the coefficient can be obtained. 、 It should be noted that, because the production process is affected by factors such as the type of oil used and the specifications of the rectangular water tank, the value before use 、 The value of needs to be calibrated according to the above coefficient determination process.

[0054] The beneficial effects of the present invention are as follows:

[0055] By leveraging the relationship between the torque of the oil film pushing mechanism and the oil film voltage, the present invention can automatically and efficiently measure the oil film volume, making the oil film measurement process intelligent. The coefficient parameters in the oil film volume formula are determined based on the step characteristics of the single-molecule oil film, improving the accuracy of oil film detection. The servo mechanism drives the oil film pushing mechanism, improving the accuracy of the torque and making the oil film detection results more accurate.

[0056] The present invention uses a method for analyzing the step characteristics of single-molecule oil films to determine their area. During the tension buildup process, the tension step characteristics are utilized to ultimately produce data that closely matches calibration with standard oil (calculated within the 30%-55% range of peak tension, with the 120Hz component as the peak frequency component). Using the proposed method to calculate single-molecule oil films significantly improves measurement consistency and repeatability, significantly improving measurement accuracy (the proposed method achieves a repeatability of 0.5%) compared to conventional algorithms (which achieve a repeatability of 2%).

[0057] An oil film meter of the present invention comprises: a main control unit, a servo system and an intelligent detection unit;

[0058] The main control unit is connected to the servo system for data exchange with the servo system; the main control unit is connected to the intelligent detection unit for data exchange with the intelligent detection unit and calculates the oil volume of the oil film to be detected based on the data collected by the intelligent detection unit. The key technical parameters of the main control unit are as follows:

[0059] The PX1811 industrial touchscreen all-in-one computer (18.5-inch, fully enclosed design) serves as the main control unit, running the Windows 10 Pro operating system and building an open control architecture. The hardware integrates a dual-port communication module and a multi-serial port expansion unit. Serial ports COM1 and COM2 are configured in RS-485 communication mode for connecting to servo drives, meeting the needs of multi-device collaborative control.

[0060] The servo system is an integrated closed-loop servo system that integrates a high-precision servo motor and driver to drive the oil film pusher to diffuse and gather the oil film. The key technical parameters of the servo system are as follows:

[0061] EtherCAT bus communication is adopted, and nanosecond-level real-time data interaction is achieved through the YK series IO controller; the closed-loop control positioning accuracy reaches ±0.01mm, the motor power dynamically matches the mechanical load, and the transmission mechanism adopts a compatible design; the introduction of the PID position compensation algorithm, combined with a high-precision hysteresis proximity switch (repeat positioning accuracy ≤ 0.01mm), achieves ±0.02mm level position calibration.

[0062] The intelligent detection unit includes a data measurement module and an intelligent calibration module. The data measurement module is used to measure the voltage between the oil film to be detected and the substrate during the pushing process, and the intelligent calibration module is used to calibrate the data measurement module. The key technical parameters of the intelligent detection unit are as follows:

[0063] Data measurement module: Equipped with a VK701NSD Ethernet 24-bit data acquisition card, it supports 4-channel true differential input (resolution 24-bit, sampling rate 400ksps), has a built-in IEPE sensor power supply module (24V / 4mA), and is directly connected to the oil film thickness sensor;

[0064] Intelligent calibration module: uses high-precision hysteresis proximity switches to achieve millimeter-level dynamic calibration of sample positions;

[0065] Distributed IO control unit: Based on the YK series distributed IO system, it realizes real-time acquisition and control of analog (4-20mA) and digital signals through the ModbusTCP protocol master controller, and supports cascade expansion of ≤32 modules.

[0066] The beneficial effects of the present invention are as follows:

[0067] The present invention uses a main control unit to exchange data with the servo system and intelligent detection unit, centralizing detection functions within the main control unit for integrated control. Parameters during the detection process are configured and parameter curves are displayed through the main control unit's user interface, making the detection process intelligent and easy to operate. Building an open detection platform using the main control unit can address the compatibility issues of traditional equipment.

[0068] Although the present invention has been described using the above preferred embodiments, they are not intended to limit the scope of protection of the present invention. Any person skilled in the art may make various changes and modifications to the above embodiments without departing from the spirit and scope of the present invention. These changes and modifications are still within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A high-precision fully automated oil film detection method, characterized in that: include: S1, making the oil film to be tested float on the substrate, pushing the oil film to be tested by the oil film pushing mechanism, measuring the voltage value between the oil film to be tested and the substrate during the pushing process by a measuring device, and obtaining the position of the oil film pushing mechanism during the pushing process; S2, taking the distance between the position of the oil film pushing mechanism and the predetermined end point as the torque of the oil film pushing mechanism; Determine the target relationship between the voltage value and the torque according to the voltage value and the torque during the pushing process; S3, when the voltage value reaches the preset value, the voltage value is used as the target voltage value, the torque corresponding to the target voltage value is obtained as the target torque through the target relationship, and the oil amount of the oil film to be detected is determined according to the target voltage value and the target torque.

2. A high-precision fully automated oil film detection method according to claim 1, characterized in that: The oil film pushing mechanism is driven by a servo motor, and the servo motor corrects the position of the oil film pushing mechanism according to a PID algorithm.

3. A high-precision fully automated oil film detection method according to claim 1, characterized in that: Before determining the target relationship between the voltage value and the torque according to the voltage value and the torque during the pushing process, it also includes: The voltage value during the driving process is filtered using the spectral threshold method.

4. A high-precision fully automated oil film detection method according to claim 1, characterized in that: The oil volume of the oil film to be tested is determined according to the target voltage value and the target torque, specifically: ； in, is the amount of oil in the oil film to be tested, 、 is the coefficient, is the target torque.

5. A high-precision fully automated oil film detection method according to claim 4, characterized in that: Sure 、 The process is as follows: An oil film with a known amount of oil is floated on a substrate, and an oil film pushing mechanism is used to push the oil film. The surface tension of the oil film during the pushing process, the position of the oil film pushing mechanism, and the time of data collection are collected. The correlation between tension and position is determined based on the time of each data collection and its corresponding surface tension of the oil film and the position of the oil film pushing mechanism. The step point of the oil film is determined according to the surface tension and the time of data collection. The time of data collection corresponding to the step point is used as the target time. The position of the oil film pushing mechanism corresponding to the target time is determined according to the correlation between tension and position. The target time is determined according to the position of the oil film pushing mechanism and the known amount of oil. 、 The value of .

6. An oil film meter, using the high-precision fully automated oil film detection method according to claim 1, characterized in that: include: Main control unit, servo system and intelligent detection unit; The main control unit is connected to the servo system and is used for data exchange with the servo system; The main control unit is connected to the intelligent detection unit and is used to exchange data with the intelligent detection unit and calculate the oil volume of the oil film to be detected based on the data collected by the intelligent detection unit; The servo system includes a servo motor and a driver. The servo system is used to drive the oil film pushing mechanism, which is used to diffuse and gather the oil film to be tested. The intelligent detection unit includes a data measurement module and an intelligent calibration module. The data measurement module is used to measure the voltage value between the oil film to be detected and the substrate during the pushing process, and the intelligent calibration module is used to calibrate the data measurement module.

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