High signal-to-noise ratio inductive detection method and system for non-ferromagnetic oil liquid scraps

Abstract

The invention belongs to the induction type oil abrasive dust sensor technology, and particularly discloses a non-ferromagnetic oil abrasive dust high signal-to-noise ratio induction type detection method and system, and the method comprises the following steps: a microcontroller carries out the control, and sends an instruction to two waveform generation chips through the microcontroller; dual-signal generation: generating two waveform and phase-adjustable periodic signals based on two waveform generation chips; the square wave frequency mixing is used for introducing a square wave as a parameter control signal to carry out frequency mixing operation; and frequency mixing difference adjustment: the optimal signal-to-noise ratio of different non-ferromagnetic chip signals is obtained by adjusting the frequency mixing difference. The frequency mixing difference between the induction signal and the reference signal can be accurately controlled, especially for non-ferromagnetic chips, different frequency mixing differences are adopted to improve the chip signal-to-noise ratio, meanwhile, square waves are introduced to serve as the reference signal to improve the chip signal amplitude, the phase shift process is simplified, the stability of the circuit is improved, and reliable data are provided for subsequent chip signals.

Description

Technical Field

[0001] The invention relates to the technical field of inductive oil wear debris sensors, and in particular to a high signal-to-noise ratio inductive detection method and system for non-ferromagnetic oil wear debris. Background Art

[0002] Metal shavings are the most common contaminants in lubricating oil. During operation, metal particle contaminants are generated due to frequent friction and wear of bearings, gears, etc. In equipment status monitoring, by analyzing the material of metal shavings, the damaged parts of the equipment can be effectively located. Taking the wind turbine bearing group as an example, iron shavings are usually related to damage to components such as tooth surfaces and rollers, while copper shavings are often related to damage to bearing cages. For the inductive shavings monitoring method, metal shavings in the oil can be divided into ferromagnetic shavings and non-ferromagnetic shavings. Ferromagnetic shavings show strong ferromagnetism in an external magnetic field and can generate an additional magnetic field in the same direction as the external magnetic field, thereby enhancing the inductance. Among these metals, iron is the most common. In contrast, non-ferromagnetic materials represented by copper will resist or weaken the magnetization, resulting in a decrease in the inductance in the coil.

[0003] In the inductive online monitoring method, the phase of the induction signal is usually adjusted to be in phase with the reference signal, and then the chip signal is obtained by mixing, filtering and other operations. The phase of the chip signal is used to determine whether the material is ferromagnetic or non-ferromagnetic, and the size of the chip is evaluated by the amplitude of the signal. There are two difficulties in the existing technology for non-ferromagnetic chip monitoring. First, the detection sensitivity of the traditional method for non-ferromagnetic chips is low, and it is impossible to monitor the smaller size of non-ferromagnetic chips; second, in order to achieve the same phase effect, the traditional method needs to use multiple phase shifting circuits for adjustment. The process is relatively cumbersome, the adjustment process is prone to errors, and it takes up a lot of circuit space, which increases the manufacturing cost. When the working conditions such as temperature and oil flow rate change, the phase needs to be adjusted additionally. In summary, how to monitor non-ferromagnetic chips with high precision and simplify the operation process is an urgent problem to be solved in the signal processing of inductive oil non-ferromagnetic chip sensors. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a high signal-to-noise ratio inductive detection method and system for non-ferromagnetic oil chips. A microcontroller is used to control a dual signal / waveform generating chip to generate a sinusoidal excitation signal and a square wave reference signal respectively. The use of a square wave as a reference signal can increase the amplitude of the chip signal. Compared with the traditional method, the amplitude can be increased by 23.37%. In addition, the signal phase of the signal generator can be quickly adjusted by the microcontroller, so as to make corresponding adjustments for chips with different properties, especially the signal amplitude of non-ferromagnetic chips can be greatly improved, which can be increased by up to 90% or more. The circuit structure of the present invention can effectively simplify the circuit, reduce the number of components, save costs and reduce the additional noise generated by redundant devices, thereby solving the problems mentioned in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid chips, comprising the following steps: S1, microcontroller control: send instructions to two waveform generation chips through the microcontroller; S2, dual signal generation: Generate two waveforms and phase-adjustable periodic signals based on two waveform generation chips; S3, square wave mixing: used to introduce square wave as reference control signal for mixing operation; S4. Mixing difference adjustment: By adjusting the mixing difference, the best signal-to-noise ratio of different non-ferromagnetic chip signals can be obtained.

[0006] Preferably, the two waveform generating chips are both AD9833 chips.

[0007] Preferably, in step S2, two waveform generating chips are used to generate a sine wave and a square wave, and used as an excitation signal and a reference signal respectively. The sine wave signal is: ; The square wave signal is: ; in, , is the gain of the cosine signal and the square wave signal, and is the initial phase of the sine wave signal and the square wave signal, is the frequency of the signal.

[0008] Preferably, the two waveform generating chips share an external crystal oscillator to ensure excitation synchronization.

[0009] Preferably, the microcontroller uses a total of 4 The interface controls the two waveform generation chips; two of which The interface is used as the chip select line of two waveform generation chips, one The interface is used as a data line to connect two waveform generation chips at the same time. The interface acts as a clock line to connect two waveform generation chips simultaneously.

[0010] Preferably, in step S3, a square wave is introduced as a reference signal for a mixing operation. After the subsequent mixing operation, the square wave reference signal is expressed as: ; in, It is the comprehensive gain. Compared with the sinusoidal signal as the reference signal, the theoretical amplitude is increased by 23.37%.

[0011] Preferably, in step S4, the initial phase of the sinusoidal signal is adjusted by the microcontroller code Initial phase with square wave signal Numeric value, Determine the initial phase of the sensor signal , mixing difference It is expressed as: ; Among them, metal chips with different properties are To optimize the amplitude of the chip signal.

[0012] On the other hand, in order to achieve the above-mentioned purpose, the present invention also provides the following technical solution: a non-ferromagnetic oil liquid debris high signal-to-noise ratio inductive detection system, comprising the following modules: A microcontroller control module, used for sending instructions to two waveform generation chips through the microcontroller; The dual signal generation module generates two waveforms based on two waveform generation chips, and the phase-adjustable periodic signals; A square wave mixing module is used to introduce a square wave as a reference control signal for mixing operation; The mixing difference adjustment module obtains the best signal-to-noise ratio of different non-ferromagnetic chip signals by adjusting the mixing difference.

[0013] The beneficial effects of the present invention are: 1) The present invention uses a microcontroller and two AD9833 chips as dual signal generators to generate phase-adjustable excitation signals and reference signals. The phase is adjusted by the microcontroller code, replacing the traditional method of adjusting multiple phase shift circuits, avoiding the complex phase adjustment process, and improving the circuit stability under different working conditions. At the same time, the number of components is reduced, the cost is reduced, and the noise introduced by too many circuits is eliminated; 2) The present invention introduces square waves as reference signals to improve the signal-to-noise ratio of the debris signal. In order to obtain the induction signal with a concentrated spectrum, the induction method uses a sinusoidal signal as the excitation. The reference signal of the traditional method is the same as the excitation signal, which is also a sinusoidal signal. However, in the mixing stage, the sinusoidal wave is not the optimal solution for the reference signal. Using a square wave as the reference signal can increase the signal amplitude by 23%; 3) The present invention adopts mixing difference adjustment, and by adjusting the mixing difference, the optimal signal-to-noise ratio of different non-ferromagnetic dust signals is obtained. The optimal mixing difference of ferromagnetic dust is usually 0, that is, the phase of the induction signal is consistent with the reference signal, and the amplitude and signal-to-noise ratio of the dust signal are the highest at this time; while the optimal mixing difference of non-ferromagnetic dust is generally around 180°, which changes with the change of the magnetic permeability of the dust. Through the dual signal generating circuit, the mixing difference can be adjusted to 180°, thereby greatly improving the signal amplitude of the non-ferromagnetic dust, thereby improving the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the process flow of the high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris in an embodiment of the present invention; Figure 2 Schematic diagram of a high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris in an embodiment of the present invention; Figure 3 This is a comparison diagram of 200 μm iron filings signals using the square wave demodulation method in the embodiment of the present invention and the traditional method; Figure 4 The signal amplitude variation diagram of 200 μm iron filings, 400 μm copper filings, and 500 μm aluminum filings under different mixing differences in the embodiment of the present invention; Figure 5 This is a signal diagram obtained under the optimal mixing frequency difference of 400 μm copper chips in an embodiment of the present invention; Figure 6 This is a signal diagram obtained by using 500 μm aluminum chips under the optimal mixing frequency difference in an embodiment of the present invention; Figure 7 Schematic diagram of the module of the high signal-to-noise ratio inductive detection system for non-ferromagnetic oil debris in an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0016] The present invention provides a technical solution: a high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid chips, such as Figure 1 and Figure 2 The method comprises the following steps: S1. Microcontroller control: Send instructions to two waveform generating chips through the microcontroller.

[0017] Furthermore, both waveform generation chips are AD9833 chips. Figure 2 They are represented by AD9833a and AD9833b respectively.

[0018] The microcontroller uses a total of 4 The interface controls the two waveform generation chips; two of which The interface is used as the chip select line of two waveform generation chips, one The interface is used as a data line to connect two waveform generation chips at the same time. The interface acts as a clock line to connect two waveform generation chips simultaneously.

[0019] S2, dual signal generation: Generates two waveforms and phase-adjustable periodic signals based on two waveform generation chips.

[0020] Two waveform generation chips (AD9833) are used to generate sine waves and square waves, which are used as excitation signals and reference signals respectively. The sine wave signal is: ; The square wave signal is: ; in, , is the gain of the cosine signal and the square wave signal, and is the initial phase of the sine wave signal and the square wave signal, is the frequency of the signal.

[0021] The two waveform generation chips share an external crystal oscillator to ensure excitation synchronization.

[0022] S3, square wave mixing: used to introduce square wave as the reference control signal for mixing operation.

[0023] A square wave is introduced as a reference signal for mixing operation. After the subsequent mixing operation, the obtained signal is expressed as: ; in, It is the comprehensive gain. Compared with the sinusoidal signal as the reference signal, the theoretical amplitude is increased by 23.37%.

[0024] S4. Mixing difference adjustment: By adjusting the mixing difference, the best signal-to-noise ratio of different non-ferromagnetic chip signals can be obtained.

[0025] Adjust the initial phase of the sinusoidal signal through the microcontroller code Initial phase with square wave signal Numeric value, Determine the initial phase of the sensor signal , mixing difference It is expressed as: ; Among them, metal chips with different properties are To optimize the amplitude of the chip signal.

[0026] The present invention uses a microcontroller and two AD9833 chips as dual signal generators to generate phase-adjustable excitation signals and reference signals. The microcontroller code is used to adjust the phase, replacing the traditional method of adjusting multiple phase shift circuits, avoiding the complex phase adjustment process, and improving the circuit stability under different working conditions. At the same time, the number of components is reduced, the cost is reduced, and the noise introduced by too many circuits is eliminated; The present invention introduces square waves as reference signals to improve the signal-to-noise ratio of the debris signal. In order to obtain the induction signal with a concentrated spectrum, the induction method uses a sinusoidal signal as the excitation. The reference signal of the traditional method is the same as the excitation signal, which is also a sinusoidal signal. However, in the mixing stage, the sinusoidal wave is not the optimal solution for the reference signal. Using a square wave as the reference signal can increase the signal amplitude by 23%; The present invention adopts mixing difference adjustment, and obtains the best signal-to-noise ratio of different non-ferromagnetic dust signals by adjusting the mixing difference. The best mixing difference of ferromagnetic dust is usually 0, that is, the phase of the induction signal is consistent with that of the reference signal, and the amplitude and signal-to-noise ratio of the dust signal are the highest at this time; while the best mixing difference of non-ferromagnetic dust is generally around 180°, which changes with the change of the magnetic permeability of the dust. Through the dual signal generating circuit, the mixing difference can be adjusted to 180°, thereby greatly improving the signal amplitude of the non-ferromagnetic dust, thereby improving the detection accuracy.

[0027] like Figure 3 As shown, it is a comparison diagram of 200μm iron filings signals using the square wave demodulation method in the embodiment of the present invention and the traditional method. It can be seen from the figure that the peak-to-peak value of the signal obtained by the square wave demodulation method is improved by 12.5% ​​compared with the traditional method.

[0028] like Figure 4As shown in the figure, it is a signal amplitude change diagram of 200μm iron filings, 400μm copper filings, and 500μm aluminum filings under different mixing differences using the method of the present invention. It can be seen from the figure that the optimal mixing difference between ferromagnetic filings and non-ferromagnetic filings is quite different. Specifically, the optimal mixing difference of ferromagnetic filings is near 0 and pi, and the optimal mixing difference of non-ferromagnetic filings is near pi / 2 and 3*pi / 2. Therefore, by adjusting the specific mixing difference, a better target filing signal can be obtained. Among them, the signal diagram of 400μm copper filings under the optimal mixing difference is as follows: Figure 5 As shown in the figure, the signal diagram of 500μm aluminum chips under the best mixing difference is as follows Figure 6 shown.

[0029] The present invention can greatly increase the signal amplitude obtained in inductive chip monitoring of non-ferromagnetic chips represented by copper and aluminum chips, and simplifies the circuit adjustment steps, thereby improving the monitoring accuracy of non-ferromagnetic chips.

[0030] Based on the same inventive concept as the above method embodiment, the present application embodiment also provides a non-ferromagnetic oil liquid debris high signal-to-noise ratio inductive detection system, which can realize the functions provided by the above method embodiment, such as Figure 7 As shown, the system includes the following modules: A microcontroller control module, used for sending instructions to two waveform generation chips through the microcontroller; The dual signal generation module generates two waveforms based on two waveform generation chips, and the phase-adjustable periodic signals; A square wave mixing module is used to introduce a square wave as a reference control signal for mixing operation; The mixing difference adjustment module obtains the best signal-to-noise ratio of different non-ferromagnetic chip signals by adjusting the mixing difference.

[0031] The present invention can accurately control the mixing difference between the induction signal and the reference signal, and obtain the chip signal after filtering. Especially for non-ferromagnetic chips, different mixing differences are used to improve the chip signal-to-noise ratio, and a square wave is introduced as a reference signal to increase the chip signal amplitude, simplify the phase shift process, and improve the stability of the circuit, providing reliable data for the subsequent chip signal.

[0032] In several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed apparatus and method can also be implemented in other ways. The apparatus and method embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the apparatus, method and computer program product according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0033] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0034] If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, an electronic device, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code. It should be noted that in this article, the term "include", "include" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or device. Without more constraints, an element defined by the phrase "comprising a..." does not exclude the existence of other identical elements in the process, method, article or apparatus comprising the element.

[0035] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0036] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0037] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0038] The "first\second" mentioned in the embodiments is only to distinguish similar objects, and does not represent a specific order for the objects. It is understandable that the "first\second" can be interchanged with the specific order or sequence where permitted. It should be understood that the objects distinguished by "first\second" can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than those illustrated or described herein.

[0039] 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 protection scope of the present invention.

Claims

1. A high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris, characterized in that: The steps include: S1, microcontroller control: send instructions to two waveform generation chips through the microcontroller; S2, dual signal generation: Generate two waveforms and phase-adjustable periodic signals based on two waveform generation chips; S3, square wave mixing: used to introduce square wave as reference control signal for mixing operation; S4. Mixing difference adjustment: By adjusting the mixing difference, the best signal-to-noise ratio of different non-ferromagnetic chip signals can be obtained.

2. The high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris according to claim 1, characterized in that: The two waveform generating chips are both AD9833 chips.

3. The high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris according to claim 1, characterized in that: In step S2, two waveform generation chips are used to generate a sine wave and a square wave, which are used as an excitation signal and a reference signal respectively. The sine wave signal is: ； The square wave signal is: ； in, , is the gain of the cosine signal and the square wave signal, and is the initial phase of the sine wave signal and the square wave signal, is the frequency of the signal.

4. The high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris according to claim 1, characterized in that: The two waveform generating chips share an external crystal oscillator to ensure excitation synchronization.

5. The high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris according to claim 1, characterized in that: The microcontroller uses a total of 4 The interface controls the two waveform generation chips; two of which The interface is used as the chip select line of two waveform generation chips, one The interface is used as a data line to connect two waveform generation chips at the same time. The interface acts as a clock line to connect two waveform generation chips simultaneously.

6. The high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris according to claim 1, characterized in that: In step S3, a square wave is introduced as a reference signal for mixing operation. After the subsequent mixing operation, the square wave reference signal is expressed as: ； in, It is the comprehensive gain. Compared with the sinusoidal signal as the reference signal, the theoretical amplitude is increased by 23.37%.

7. The high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris according to claim 1, characterized in that: In step S4, the initial phase of the sinusoidal signal is adjusted by the microcontroller code Initial phase with square wave signal Numeric value, Determine the initial phase of the sensor signal , mixing difference It is expressed as: ； Among them, metal chips with different properties are To optimize the amplitude of the chip signal.

8. A system according to the high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris according to any one of claims 1 to 7, characterized in that: Includes the following modules: A microcontroller control module, used for sending instructions to two waveform generation chips through the microcontroller; The dual signal generation module generates two waveforms based on two waveform generation chips, and the phase-adjustable periodic signals; A square wave mixing module is used to introduce a square wave as a reference control signal for mixing operation; The mixing difference adjustment module obtains the best signal-to-noise ratio of different non-ferromagnetic chip signals by adjusting the mixing difference.

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