A non-ferromagnetic oil debris high signal-to-noise ratio inductive detection method and system

Abstract

The present invention belongs to the technology of inductive oil debris sensors, and specifically discloses a method and system for inductive detection of non-ferromagnetic oil debris with high signal-to-noise ratio. The method includes the following steps: controlled by a microcontroller, the microcontroller sends instructions to two waveform generation chips; dual signal generation, based on the two waveform generation chips, two periodic signals with adjustable waveforms and phases are generated; square wave mixing, which is used to introduce a square wave as a reference control signal for mixing operation; mixing difference adjustment, by adjusting the mixing difference, the best signal-to-noise ratio of different non-ferromagnetic debris signals is obtained. The present invention can accurately control the mixing difference between the inductive signal and the reference signal. Especially for non-ferromagnetic debris, different mixing differences are used to improve the signal-to-noise ratio of the debris. At the same time, a square wave is introduced as the reference signal to increase the amplitude of the debris signal, simplify the phase shift process, and improve the stability of the circuit, providing reliable data for the subsequent debris signal.

Description

Technical Field

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

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

[0003] In inductive on-line monitoring methods, the phase of the inductive signal is usually adjusted to be in the same phase as the reference signal, and then operations such as mixing and filtering are used to obtain the debris signal. The material of the debris is judged to be ferromagnetic or non-ferromagnetic by the phase of the debris signal, and the size of the debris is evaluated by the amplitude of the signal. There are two difficulties in the prior art for non-ferromagnetic debris monitoring. First, the traditional method has low detection sensitivity for non-ferromagnetic debris and cannot monitor non-ferromagnetic debris with smaller sizes. Second, in order to achieve the same-phase effect, the traditional method needs to use multiple phase-shifting circuits for adjustment. This process is relatively cumbersome, the adjustment process is prone to errors, and it requires a large amount of circuit space, increasing the manufacturing cost. When working conditions such as temperature and oil flow rate change, the phase needs to be adjusted additionally. To sum up, how to perform high-precision monitoring of non-ferromagnetic debris while simplifying the operation process is an urgent problem to be solved in the signal processing of inductive oil non-ferromagnetic debris sensors. Summary of the Invention

[0004] To solve the problems existing in the prior art, the present invention provides a non-ferromagnetic oil debris high signal-to-noise ratio inductive detection method and system. A microcontroller is used to control a dual-signal / waveform generation chip to generate a sine excitation signal and a square-wave reference signal respectively. Using a square wave as the reference signal can increase the amplitude of the debris signal. Compared with the traditional method, the amplitude can be increased by 23.37%. In addition, the microcontroller can quickly adjust the signal phase of the signal generator, so as to perform corresponding adjustment for debris with different attributes. In particular, the signal amplitude of non-ferromagnetic debris can be greatly increased, with a maximum increase of more than 90%. The circuit structure of the present invention can effectively simplify the circuit, reduce the number of components, save costs while reducing the extra noise generated by redundant devices, and solve the problems mentioned in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A non-ferromagnetic oil debris high signal-to-noise ratio inductive detection method, including the following steps:

[0006] S1. Microcontroller control: Send instructions to two waveform generation chips through the microcontroller;

[0007] S2. Dual-signal generation: Generate two waveforms and phase-adjustable periodic signals based on two waveform generation chips;

[0008] S3. Square-wave mixing: Used to introduce a square wave as a reference control signal for mixing operation;

[0009] S4. Mixing difference adjustment: By adjusting the mixing difference, obtain the best signal-to-noise ratio of different non-ferromagnetic debris signals.

[0010] Preferably, both of the two waveform generation chips are AD9833 chips.

[0011] Preferably, in step S2, use two waveform generation chips to generate a sine wave and a square wave, and use them as the excitation signal and the reference signal respectively. The sine wave signal is:

[0012] ;

[0013] The square-wave signal is:

[0014] ;

[0015] Among them, , are the gains of the cosine signal and the square-wave signal, and are the initial phases of the sine signal and the square-wave signal, is the frequency of the signal.

[0016] Preferably, the two waveform generation chips share an external crystal oscillator to ensure excitation synchronization.

[0017] Preferably, the microcontroller uses a total of 4 interfaces to control the two waveform generation chips; two of the interfaces are respectively used as chip select lines for the two waveform generation chips, one interface is used as a data line and is connected to the two waveform generation chips simultaneously, and one interface is used as a clock line and is connected to the two waveform generation chips simultaneously.

[0018] Preferably, in step S3, a square wave is introduced as a reference signal for mixing operation. After the subsequent mixing operation of the square wave reference signal, the obtained signal is expressed as:

[0019] ;

[0020] wherein, is the comprehensive gain, and compared with the sine signal as the reference signal, the theoretical amplitude is increased by 23.37%.

[0021] Preferably, in step S4, the initial phase of the sine signal and the initial phase of the square wave signal are adjusted through the microcontroller code, which determines the initial phase of the sensor signal. The mixing difference is expressed as:

[0022] ;

[0023] wherein, metal debris of different properties optimizes the amplitude of the debris signal by changing .

[0024] On the other hand, to achieve the above object, the present invention also provides the following technical solution: a non-ferromagnetic oil debris high signal-to-noise ratio inductive detection system, including the following modules:

[0025] A microcontroller control module, which is used to send instructions to two waveform generation chips through the microcontroller;

[0026] A dual-signal generation module, which generates two waveforms and phase-adjustable periodic signals based on two waveform generation chips;

[0027] A square wave mixing module, which is used to introduce a square wave as a reference control signal for mixing operation;

[0028] A mixing difference adjustment module, which obtains the best signal-to-noise ratio of different non-ferromagnetic debris signals by adjusting the mixing difference.

[0029] The beneficial effects of the present invention are:

[0030] 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;

[0031] 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%;

[0032] 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

[0033] Figure 1 Schematic diagram of the steps of the high signal-to-noise ratio inductive detection method for non-ferromagnetic oil liquid debris in an embodiment of the present invention;

[0034] 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;

[0035] 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;

[0036] 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;

[0037] 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;

[0038] 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;

[0039] Figure 7Schematic diagram of the non-ferromagnetic oil debris high signal-to-noise ratio inductive detection system module in the embodiment of the present invention. Detailed implementation manners

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] The present invention provides a technical solution: a non-ferromagnetic oil debris high signal-to-noise ratio inductive detection method, as Figure 1 and Figure 2 described, including the following steps:

[0042] S1. Microcontroller control: Send instructions to two waveform generation chips through the microcontroller.

[0043] Further, both waveform generation chips are AD9833 chips, and are represented by AD9833a and AD9833b respectively in Figure 2 .

[0044] The microcontroller uses a total of 4 interfaces to control the two waveform generation chips; two of the interfaces are respectively used as chip select lines of the two waveform generation chips, one interface is used as a data line and is connected to the two waveform generation chips at the same time, and one interface is used as a clock line and is connected to the two waveform generation chips at the same time.

[0045] S2. Dual signal generation: Generate two waveforms and phase-adjustable periodic signals based on the two waveform generation chips.

[0046] Use two waveform generation chips (AD9833) to generate a sine wave and a square wave, and use them as the excitation signal and the reference signal respectively. The sine wave signal is:

[0047] ;

[0048] The square wave signal is:

[0049] ;

[0050] Wherein, , are the gains of the cosine signal and the square wave signal, and are the initial phases of the sine signal and the square wave signal, is the frequency of the signal.

[0051] Two waveform generation chips share an external crystal oscillator to ensure excitation synchronization.

[0052] S3, Square wave mixing: Used to introduce a square wave as a reference control signal for mixing operations.

[0053] Introduce a square wave as a reference signal for mixing operations. After the subsequent mixing operations on the square wave reference signal, the resulting signal is expressed as:

[0054] ;

[0055] Where, is the combined gain, which is 23.37% higher in theoretical amplitude compared to using a sine signal as the reference signal.

[0056] S4, Mixing difference adjustment: By adjusting the mixing difference, the best signal-to-noise ratio of different non-ferromagnetic debris signals can be obtained.

[0057] Adjust the initial phase of the sine signal through the microcontroller code and the initial phase of the square wave signal values, determine the initial phase of the sensor signal , the mixing difference is expressed as:

[0058] ;

[0059] Where, metal debris of different properties optimizes the amplitude of the debris signal by changing .

[0060] The present invention uses a microcontroller and two AD9833 chips as dual signal generators to generate excitation signals and reference signals with adjustable phases. By adjusting the phase through the microcontroller code, it replaces the traditional method of adjusting with multiple phase-shifting circuits, avoids the complex phase adjustment process, improves the circuit stability under different working conditions, reduces the number of devices, lowers the cost, and eliminates the noise introduced by excessive circuits;

[0061] The present invention introduces a square wave as a reference signal to improve the signal-to-noise ratio of the debris signal. In order to obtain an induction signal with concentrated spectrum, the inductive method uses a sine signal as the excitation. The reference signal and the excitation signal of the traditional method are of the same origin and are also sine signals. However, in the mixing stage, the sine 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%;

[0062] The present invention adopts mixing difference adjustment. By adjusting the mixing difference, the optimal signal-to-noise ratio of different non-ferromagnetic debris signals is obtained. The optimal mixing difference of ferromagnetic debris is usually 0, that is, the phases of the induction signal and the reference signal are consistent. At this time, the amplitude and signal-to-noise ratio of the debris signal are the highest; while the optimal mixing difference of non-ferromagnetic debris is generally around 180°, and it changes with the change of the magnetic permeability of the debris. Through the dual-signal generation circuit, the mixing difference can be adjusted to 180°, thereby greatly increasing the signal amplitude of non-ferromagnetic debris, and thus improving the detection accuracy.

[0063] As Figure 3 shown, it is a comparison chart of the 200μm iron debris signal between the square wave demodulation method adopted 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 increased by 12.5% compared with the traditional method.

[0064] As Figure 4 shown, it is a signal amplitude change chart of 200μm iron debris, 400μm copper debris, and 500μm aluminum debris under different mixing differences by using the method of the present invention. It can be seen from the figure that the difference in the optimal mixing difference between ferromagnetic debris and non-ferromagnetic debris is relatively large. Specifically, the optimal mixing difference of ferromagnetic debris is around 0 and π, and the optimal mixing difference of non-ferromagnetic debris is around π / 2 and 3π / 2. Therefore, by adjusting the specific mixing difference value, a better target debris signal can be obtained. Among them, the signal diagram of 400μm copper debris obtained under the optimal mixing difference is as Figure 5 shown, and the signal diagram of 500μm aluminum debris obtained under the optimal mixing difference is as Figure 6 shown.

[0065] The present invention can greatly increase the signal amplitude of non-ferromagnetic debris represented by copper and aluminum debris in inductive debris monitoring, and at the same time simplifies the circuit adjustment steps, thereby improving the monitoring accuracy of non-ferromagnetic debris.

[0066] Based on the same inventive concept as the above method embodiment, the embodiment of the present application also provides a high signal-to-noise ratio inductive detection system for non-ferromagnetic oil fluid debris. This system can implement the functions provided by the above method embodiment, such as Figure 7 shown, the system includes the following modules:

[0067] A microcontroller control module, which is used to send instructions to two waveform generation chips through the microcontroller;

[0068] A dual-signal generation module, which generates two waveforms and phase-adjustable periodic signals based on two waveform generation chips;

[0069] A square wave mixing module, which is used to introduce a square wave as a reference control signal for mixing operations;

[0070] The mixing difference adjustment module obtains the optimal signal-to-noise ratio of different non-ferromagnetic debris signals by adjusting the mixing difference.

[0071] The present invention can accurately control the mixing difference between the induction signal and the reference signal, and obtain the debris signal after filtering. Especially for non-ferromagnetic debris, different mixing differences are used to improve the signal-to-noise ratio of the debris. At the same time, a square wave is introduced as the reference signal to increase the amplitude of the debris signal, simplify the phase shift process, and improve the stability of the circuit, providing reliable data for the subsequent processing of the debris signal.

[0072] In several embodiments provided by the embodiments of the present invention, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device and method embodiments described above are only illustrative. For example, the flowcharts and block diagrams in the drawings show the possible architectures, functions, and operations of devices, methods, and computer program products according to multiple embodiments of the present invention. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, program segment, or part of 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 blocks may occur in a different order than marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, as well as the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0073] In addition, the functional modules in each embodiment of the present invention can be integrated together to form an independent part, or each module can exist alone, or two or more modules can be integrated to form an independent part.

[0074] When the above-mentioned functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, an electronic device, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs. It should be noted that in this article, the terms "include", "comprise", or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such a process, method, article, or device. Without further limitations, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article, or device including the said element.

[0075] 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", "the", and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0076] It should be understood that the term "and / or" used herein is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0077] Depending on the context, the word "if" as used herein can be interpreted as "when", "while", "in response to determining", or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detecting (stated condition or event)" can be interpreted as "when determined", "in response to determining", "when detecting (stated condition or event)", or "in response to detecting (stated condition or event)".

[0078] The "first / second" mentioned in the embodiments is only used to distinguish similar objects and does not represent a specific order for the objects. It can be understood that the "first / second" can be interchanged with a specific order or sequence under allowable circumstances. It should be understood that the objects distinguished by the "first / second" can be interchanged under appropriate circumstances so that the embodiments described herein can be implemented in an order other than those illustrated or described herein.

[0079] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A non-ferromagnetic oil debris high signal-to-noise ratio inductive detection method, characterized in that It includes the following steps: S1. Microcontroller control: Send instructions to two waveform generation chips through the microcontroller; S2. Dual-signal generation: Generate two periodic signals with adjustable phases based on two waveform generation chips; Use two waveform generation chips to generate a sine wave and a square wave, and use them as the excitation signal and the reference signal respectively. The sine wave signal is: The square wave signal is: Among them, A c and A q are the gains of the cosine signal and the square wave signal, and are the initial phases of the sine signal and the square wave signal, and f is the frequency of the signal; S3. Square wave mixing: Used to introduce a square wave as a reference control signal for mixing operations; S4. Mixing difference adjustment: By adjusting the mixing difference, the best signal-to-noise ratio of different non-ferromagnetic debris signals is obtained; the initial phase of the sine signal is adjusted through the microcontroller code and the initial phase of the square wave signal value, determines the initial phase of the sensor signal Mixing difference is expressed as: Among them, metal filings with different properties are optimized for the amplitude of the filing signal by changing to optimize the amplitude of the filing signal.

2. The non-ferromagnetic oil debris high signal-to-noise ratio inductive detection method according to claim 1, wherein: Both of the two waveform generation chips are AD9833 chips.

3. The non-ferromagnetic oil debris high signal-to-noise ratio inductive detection method according to claim 1, wherein: The two waveform generation chips share an external crystal oscillator to ensure excitation synchronization.

4. The non-ferromagnetic oil debris high signal-to-noise ratio inductive detection method according to claim 1, characterized in that: The microcontroller uses a total of 4 I / O interfaces to control the two waveform generation chips; Two of the I / O interfaces are used as chip select lines for the two waveform generation chips respectively, one I / O interface is used as a data line and is connected to the two waveform generation chips simultaneously, and one I / O interface is used as a clock line and is connected to the two waveform generation chips simultaneously.

5. The non-ferromagnetic oil fluid debris high signal-to-noise ratio inductive detection method according to claim 1, characterized in that: In step S3, a square wave is introduced as a reference signal for mixing operations. After the subsequent mixing operations, the obtained signal is expressed as: Mq = 2A / π Where, A is the combined gain, and compared with using a sine signal as the reference signal, the theoretical amplitude is increased by 23.37%.

6. A system for the non-ferromagnetic oil debris high signal-to-noise ratio inductive detection method according to any one of claims 1-5, characterized in that: It includes the following modules: Microcontroller control module, used to send instructions to two waveform generation chips through the microcontroller; Dual-signal generation module, generating two periodic signals with adjustable phases based on two waveform generation chips; Square wave mixing module, used to introduce a square wave as a reference control signal for mixing operations; Mixing difference adjustment module, obtaining the best signal-to-noise ratio of different non-ferromagnetic debris signals by adjusting the mixing difference.

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