Radial and axial nonlinear decoupling device and method for edge inductive sensor

Abstract

The invention provides a radial and axial nonlinear decoupling device and method of a marginal inductive sensor, and belongs to the technical field of rotating shaft displacement detection, and the device comprises a signal excitation source which is used for outputting excitation signals to a radial displacement sensor and an axial displacement sensor of the marginal inductive sensor; the signal processing unit is used for extracting a first electric signal for representing radial displacement based on a feedback signal output by the radial displacement sensor and extracting a second electric signal for representing axial displacement based on a feedback signal output by the axial displacement sensor; and the digital control unit is used for fitting an influence rule of different radial displacements on an output signal of the axial displacement sensor based on the first electric signal, the second electric signal and a coupling model of the edge inductance type sensor, and carrying out nonlinear decoupling on the radial displacements and the axial displacements based on the influence rule. According to the invention, the problem of inaccurate axial displacement detection of the edge inductive sensor can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of shaft displacement detection, and particularly to a radial and axial non-linear decoupling device and method for an edge inductive sensor. Background Art

[0002] A magnetic levitation bearing is a bearing device that uses electromagnetic force to levitate a rotor, which can replace traditional mechanical bearings and achieve non-contact operation between the rotor and the stator. In current magnetic levitation motors, although the detection of eddy current sensors is relatively sensitive, there is a certain attenuation phenomenon in the signal transmission of eddy current sensors, and at the same time, the anti-interference ability is weak.

[0003] Compared with eddy current sensors, inductive sensors have a larger linear range, stronger anti-interference ability, and are more sensitive when detecting small displacements, making them more suitable for magnetic bearing systems.

[0004] However, there is a coupling situation between the radial displacement of the edge inductive sensor and the change in axial inductance, that is, both the radial displacement and the axial displacement will affect the change in the axial inductance of the edge inductive sensor, that is, there is a coupling between the radial and axial directions of the edge inductive sensor, resulting in inaccurate detection of the axial displacement of the edge inductive sensor. Summary of the Invention

[0005] In view of this, it is necessary to provide a radial and axial non-linear decoupling device and method for an edge inductive sensor to solve the problem of inaccurate detection of the axial displacement of the edge inductive sensor.

[0006] To solve the above problems, in a first aspect, the present invention provides a radial and axial non-linear decoupling device for an edge inductive sensor, including: A signal excitation source for outputting an excitation signal to the radial displacement sensor and the axial displacement sensor of the edge inductive sensor; A signal processing unit for extracting a first electrical signal for characterizing the radial displacement based on the feedback signal output by the radial displacement sensor, and extracting a second electrical signal for characterizing the axial displacement based on the feedback signal output by the axial displacement sensor; A digital control unit for fitting the influence law of different radial displacements on the output signal of the axial displacement sensor based on the first electrical signal, the second electrical signal and the coupling model of the edge inductive sensor, and performing non-linear decoupling of the radial displacement and the axial displacement based on the influence law.

[0007] In a possible implementation manner, the signal excitation source includes: A crystal oscillator for outputting an original excitation signal; A filter circuit for filtering the original excitation signal to obtain a filtered signal; An inverting amplifier circuit is used to invert and amplify the filtered signal to obtain a sine excitation signal or a cosine excitation signal.

[0008] In a possible implementation, the signal processing unit includes: A filtering and detection circuit is used to filter and detect the feedback signal and then output a DC voltage signal; A demodulation unit is used to extract a first electrical signal for characterizing the radial displacement of the edge inductive sensor and a second electrical signal for characterizing the axial displacement of the edge inductive sensor based on the DC voltage signal.

[0009] In a possible implementation, the filtering and detection circuit includes: A first signal amplification unit is used to receive the feedback signal and the reference signal and amplify the feedback signal and the reference signal respectively; A differential unit is used to perform differential processing on the amplified feedback signal and reference signal to obtain a differential signal; A second signal amplification unit is used to amplify the differential signal to obtain a DC voltage signal.

[0010] In a possible implementation, the first signal amplification unit includes: a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a second capacitor, a third capacitor, a first diode, and a second diode; The positive input terminal of the first operational amplifier receives the feedback signal through the first resistor, and the output terminal of the first operational amplifier is output through the series-connected second resistor and the first diode. The second capacitor and the third capacitor are respectively connected to two intermediate stages of the first operational amplifier; The positive input terminal of the second operational amplifier accesses the reference signal through the third resistor, and the output terminal of the second operational amplifier is output through the series-connected fourth resistor and the second diode.

[0011] In a possible implementation, the first signal amplification unit further includes: a fifth resistor and a first capacitor; The fifth resistor and the first capacitor form a low-pass filtering unit and are connected to the first resistor.

[0012] In a possible implementation, the differential unit includes: a series-connected sixth resistor and seventh resistor, and a series-connected fourth capacitor and fifth capacitor; the series-connected sixth resistor and seventh resistor are in parallel with the series-connected fourth capacitor and fifth capacitor.

[0013] In a possible implementation, the second signal amplification unit includes: a third operational amplifier, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, and a tenth capacitor; The positive input terminal of the third operational amplifier is connected to the differential unit through the eighth resistor, and the negative input terminal of the third operational amplifier is connected to the differential unit through the ninth resistor; The eighth capacitor and the ninth capacitor are respectively connected to two intermediate stages of the third operational amplifier; The tenth resistor and the sixth capacitor are both connected in parallel between the positive input terminal and the output terminal of the third operational amplifier; The eleventh resistor and the seventh capacitor are both connected in parallel between the negative input terminal and the output terminal of the third operational amplifier; The output terminal of the third operational amplifier is grounded through the twelfth resistor and the thirteenth resistor in sequence, and the tenth capacitor is connected in parallel with the thirteenth resistor.

[0014] In a possible implementation, an edge inductive sensor includes: a three-layer iron core; the middle-layer iron core in the three-layer iron core and the coil fixed on the middle-layer iron core form a radial displacement sensor, and the upper and lower iron cores of the three-layer iron core and the coils fixed on the upper and lower iron cores respectively form an axial displacement sensor.

[0015] In a second aspect, the present invention further provides a method for radial and axial non-linear decoupling of an edge inductive sensor. The method is applied to the above-mentioned device, and the method includes: Output an excitation signal from a signal excitation source to the radial displacement sensor and the axial displacement sensor of the edge inductive sensor; Based on the signal processing unit and according to the feedback signal output by the radial displacement sensor, extract a first electrical signal for characterizing the radial displacement, and based on the feedback signal output by the axial displacement sensor, extract a second electrical signal for characterizing the axial displacement; Based on the digital control unit and according to the first electrical signal, the second electrical signal, and the coupling model of the edge inductive sensor, fit the influence law of different radial displacements on the output signal of the axial displacement sensor, and perform non-linear decoupling on the radial displacement and the axial displacement based on the influence law.

[0016] The beneficial effects of adopting the above implementation method are as follows: The radial and axial non-linear decoupling device and method for an edge inductive sensor provided by the present invention. After receiving an excitation signal, the radial displacement sensor can detect the radial displacement of the sensor and output the radial displacement as a feedback signal. After receiving an excitation signal, the axial displacement sensor can detect the axial displacement of the sensor and output the axial displacement as a feedback signal.

[0017] Both the first electrical signal and the second electrical signal are obtained in real time during the actual operation of the edge inductive sensor. The coupling model of the edge inductive sensor is a model obtained by simulating the physical parameters of the edge inductive sensor. The digital control unit combines the first electrical signal, the second electrical signal, and the coupling model of the edge inductive sensor, and can simulate the working principle between the radial displacement sensor and the axial displacement sensor and the correlation between the input and output signals, so as to fit the influence law of different radial displacements on the output signal of the axial displacement sensor. Based on the influence law, non-linear decoupling of the radial displacement and the axial displacement is performed. After non-linear decoupling of the radial displacement and the axial displacement, the influence of the radial displacement and the axial displacement on the change of the axial inductance of the edge inductive sensor is avoided, thereby solving the problem of inaccurate detection of the axial displacement of the edge inductive sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of an embodiment of the radial and axial non-linear decoupling device for an edge inductive sensor provided by the present invention; Figure 2 It is a circuit diagram of an embodiment of the signal excitation source provided by the present invention; Figure 3 It is a circuit diagram of an embodiment of the filtering and detection circuit provided by the present invention; Figure 4 It is a schematic structural diagram of the edge inductive sensor provided by the present invention; Figure 5 It is a displacement transformation diagram of the axial sensor in the X, Y, and Z directions provided by the present invention; Figure 6 It is a flowchart of an embodiment of the radial and axial non-linear decoupling method for an edge inductive sensor provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0021] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0022] In the embodiments of the present invention, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, device, product, or equipment that includes a series of steps or modules does not necessarily have to be limited to those steps or modules clearly listed, but may include other steps or modules that are not clearly listed or are inherent to these processes, methods, products, or equipment.

[0023] In the embodiments of the present invention, the naming or numbering of steps does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The named or numbered process steps can be changed in the execution order according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0024] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0025] As Figure 1 shown, the present invention provides a radial and axial nonlinear decoupling device for an edge inductive sensor, including: A signal excitation source 104 for outputting an excitation signal to the radial displacement sensor and the axial displacement sensor of the edge inductive sensor 103; A signal processing unit 102 for extracting a first electrical signal for characterizing the radial displacement based on the feedback signal output by the radial displacement sensor, and extracting a second electrical signal for characterizing the axial displacement based on the feedback signal output by the axial displacement sensor; A digital control unit 101 for fitting the influence law of different radial displacements on the output signal of the axial displacement sensor based on the first electrical signal, the second electrical signal, and the coupling model of the edge inductive sensor 103, and performing nonlinear decoupling of the radial displacement and the axial displacement based on the influence law.

[0026] It can be understood that the edge inductive sensor 103 provided by the present invention can be an edge inductive sensor 103 with a large gap. After receiving the excitation signal, the radial displacement sensor outputs a corresponding feedback signal, and after receiving the excitation signal, the axial displacement sensor also outputs a corresponding feedback signal.

[0027] The decoupling device provided by the present invention includes: a signal excitation source 104, a demodulation unit, and a digital control unit 101. The digital control unit 101 includes: a decoupling control module and a sampling unit, where: Signal excitation source 104: used to generate the excitation signal of the inductive sensor; the excitation signal can be a sine signal or a square wave signal; Radial displacement sensor probe: used to detect the radial displacement of the edge inductive sensor 103 corresponding to the rotating shaft. Specifically, during the detection process, the radial displacement sensor probe converts the inductance into a position signal; Axial displacement sensor probe: used to detect the axial displacement of the edge inductive sensor 103 corresponding to the rotating shaft and convert the inductance into a position signal; Demodulation unit: used to extract the electrical signal reflecting the position change; Sampling unit: used to collect the demodulated electrical signal; Decoupling control module: connected to the magnetic bearing controller, used to perform decoupling control of the radial and axial displacements according to the signal output by the sampling unit and the coupling model between the radial displacement sensor probe and the axial displacement sensor probe of the edge inductive sensor 103. The decoupling control module can also receive the physical parameters of the radial displacement sensor probe and the axial displacement sensor probe of the edge inductive sensor 103 for modeling. The present invention combines the coupling model and numerical fitting to be able to separate the signals of the radial displacement and the axial displacement in real time.

[0028] On the other hand, based on the above-mentioned radial and axial nonlinear decoupling device of the edge inductive sensor 103, the present invention can also provide a corresponding nonlinear decoupling control method. The digital control unit 101 can automatically adjust the parameters of the nonlinear decoupling method according to the changes in the working intervals of the specific rotor positions in the axial and radial directions to adapt to different working conditions.

[0029] Compared with the prior art, the solution provided by the present invention can achieve the following beneficial effects: (1) Based on the first electrical signal, the second electrical signal, and the coupling model of the edge inductive sensor 103, the digital control unit 101 combines the radial displacement and the axial displacement of the edge inductive sensor 103, fits the influence on the output of the axial sensor in different radial displacement cases, and effectively eliminates the coupling influence of the radial displacement on the axial displacement detection; (2) Combine the first electrical signal and the second electrical signal with the coupling model of the edge inductive sensor 103, so that the parameters of the non-linear decoupling method can be automatically adjusted according to the changes in the working ranges of the specific rotor positions in the axial and radial directions to adapt to different working conditions.

[0030] In some embodiments, the signal excitation source 104 includes: A crystal oscillator for outputting an original excitation signal; A filter circuit for filtering the original excitation signal to obtain a filtered signal; An inverting amplifier circuit for inverting and amplifying the filtered signal to obtain a sine excitation signal or a cosine excitation signal.

[0031] It can be understood that, as Figure 2 shown, the signal excitation source 104 of the edge inductive sensor 103 in this embodiment is given by a crystal oscillator, and after high-pass filtering, low-pass filtering, an inverting amplifier, etc., a sine excitation signal is output. After the excitation signal passes through the sensor inductance coil, a sine feedback signal is differentially output and enters Figure 3 the filtering and detection circuit shown.

[0032] Or, the signal excitation source 104 of the edge inductive sensor 103 is given by a crystal oscillator, and after high-pass filtering, low-pass filtering, an inverting amplifier, etc., a cosine excitation signal is output. After the excitation signal passes through the sensor inductance coil, a cosine feedback signal is differentially output and enters Figure 3 the filtering and detection circuit shown.

[0033] In some embodiments, the signal processing unit 102 includes: A filtering and detection circuit for filtering and detecting the feedback signal and then outputting a DC voltage signal; A demodulation unit for extracting, based on the DC voltage signal, a first electrical signal for characterizing the radial displacement of the edge inductive sensor 103 and a second electrical signal for characterizing the axial displacement of the edge inductive sensor 103.

[0034] It can be understood that after the feedback signal enters the filtering and detection circuit, the clutter is filtered out by a low-pass filter and then enters a follower circuit to improve the load-carrying capacity of the circuit; the feedback signal after being rectified by a diode and the signal after the reference signal is rectified and followed enter an amplifier together, and then a DC voltage signal is output after low-pass filtering; the DC voltage signal enters the controller demodulation unit to extract the electrical signal reflecting the position change; then it enters the sampling unit for the digital control module to collect the demodulated signal; finally, it enters the decoupling control module, which is connected to the magnetic bearing controller for decoupling control of the radial and axial displacements according to the directly collected signal and the probe coupling model.

[0035] In some embodiments, the filtering and detection circuit includes: A first signal amplification unit, configured to receive the feedback signal and the reference signal, and amplify the feedback signal and the reference signal respectively; A differential unit, configured to perform differential processing on the amplified feedback signal and reference signal to obtain a differential signal; A second signal amplification unit, configured to amplify the differential signal to obtain a DC voltage signal.

[0036] It can be understood that both the first signal amplification unit and the second signal amplification unit perform reverse amplification on the input signals, and both the first signal amplification unit and the second signal amplification unit can carry filtering and protection function modules.

[0037] In some embodiments, as Figure 3 shown, the first signal amplification unit includes: a first operational amplifier U1A, a second operational amplifier U1B, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a second capacitor C2, a third capacitor C3, a first diode D1, and a second diode D2; The positive input terminal of the first operational amplifier U1A receives the feedback signal through the first resistor R1, and the output terminal of the first operational amplifier U1A outputs through the series-connected second resistor R2 and the first diode D1. The second capacitor C2 and the third capacitor C3 are respectively connected to two intermediate stages of the first operational amplifier U1A; The positive input terminal of the second operational amplifier U1B accesses the reference signal through the third resistor R3, and the output terminal of the second operational amplifier U1B outputs through the series-connected fourth resistor R4 and the second diode D2.

[0038] It can be understood that both the first operational amplifier U1A and the second operational amplifier U1B can be inverting amplifiers, which can achieve a specific frequency response, such as low-pass filtering. The feedback paths of the two operational amplifiers can adjust the low-frequency or high-frequency response to enhance stability. The diodes and resistors at the output terminals of the two operational amplifiers form an output limiting circuit to prevent overvoltage from damaging subsequent circuits.

[0039] The circuit of the first signal amplification unit is a feedback-type amplification circuit with output protection, and output limiting is achieved through diodes.

[0040] In some embodiments, the first signal amplification unit further includes: a fifth resistor R5 and a first capacitor C1; The fifth resistor R5 and the first capacitor C1 form a low-pass filtering unit and are connected to the first resistor R1.

[0041] It can be understood that the circuit of the first signal amplification unit is a feedback amplification circuit with filtering, and the frequency response is adjusted through an RC network.

[0042] In some embodiments, the differential unit includes: a sixth resistor R6 and a seventh resistor R7 connected in series, and a fourth capacitor C4 and a fifth capacitor C5 connected in series; the series-connected sixth resistor R6 and seventh resistor R7 are connected in parallel with the series-connected fourth capacitor C4 and fifth capacitor C5.

[0043] It can be understood that as the differential unit in the detection circuit, it can eliminate noise and carrier leakage through common-mode rejection, can also improve linearity, reduce distortion, and support phase-sensitive detection and dynamic range compression.

[0044] In some embodiments, the second signal amplification unit includes: a third operational amplifier U2, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, and a tenth capacitor C10; The positive input terminal of the third operational amplifier U2 is connected to the differential unit through the eighth resistor R8, and the negative input terminal of the third operational amplifier U2 is connected to the differential unit through the ninth resistor R9; The eighth capacitor C8 and the ninth capacitor C9 are respectively connected to two intermediate stages of the third operational amplifier U2; The tenth resistor R10 and the sixth capacitor C6 are both connected in parallel between the positive input terminal and the output terminal of the third operational amplifier U2; The eleventh resistor R11 and the seventh capacitor C7 are both connected in parallel between the negative input terminal and the output terminal of the third operational amplifier U2; The output terminal of the third operational amplifier U2 is grounded sequentially through the twelfth resistor R12 and the thirteenth resistor R13, and the tenth capacitor C10 is connected in parallel with the thirteenth resistor R13.

[0045] It can be understood that the working principle of the second signal amplification unit is similar to that of the first signal amplification unit, and it can amplify the input signal in the reverse direction.

[0046] In some embodiments, as Figure 4 shown, the edge inductive sensor 103 includes: a three-layer iron core 403; the middle-layer iron core 403 in the three-layer iron core 403 and the coil fixed on the middle-layer iron core 403 form a radial displacement sensor, and the upper and lower iron cores 403 in the three-layer iron core 403 and the coils fixed on the upper and lower iron cores 403 respectively form an axial displacement sensor.

[0047] It can be understood that the edge inductive sensor 103 in this embodiment includes: a sensor housing 401, a laminated insulating ring 402, a core 403 assembly, a PCB 404 (printed circuit board), a coil, a screw 406, and an insulating spacer 407. Each layer of the core 403 has 8 teeth, and 1 laminated insulating ring 402 is used to separate between two cores 403. 1 laminated insulating ring 402 is also used to separate between the bottom core 403 and the sensor housing 401. 1 laminated insulating ring 402 and 1 insulating spacer 407 are used to separate between the top core 403 and the PCB 404. The coil is wound on a coil bobbin 405 to fix the coil, and the screw 406 is used to fix the PCB 404, the core 403, the insulating ring, the spacer, and the sensor housing 401.

[0048] Among the 3 layers of cores 403 of the edge inductive sensor 103, the middle layer core 403 is a radial displacement detection sensor, and the upper and lower layers of cores 403 are axial displacement detection sensors of the edge inductive sensor 103.

[0049] Two adjacent coils of the middle layer core 403 are connected in series to form a group, and the two opposite groups of coils are connected in a differential manner for use in detecting the displacement of a single degree of freedom in the radial direction. For the upper and lower layers of cores 403, 8 coils of each layer of core 403 are connected in series to form a group, and the two groups of coils of the upper and lower layers are connected in a differential manner for use in detecting the axial displacement.

[0050] In some embodiments, the decoupling control unit is configured to, based on the first electrical signal, the second electrical signal, and the coupling model, fit to obtain the non-linearity of the inductance of the axial displacement sensor with respect to the radial displacement, determine the influence law of the radial displacement on the inductance of the axial displacement sensor based on the non-linearity, and generate a decoupling signal based on the inductance influence law, and output the decoupling signal to the magnetic bearing controller to perform non-linear decoupling on the radial displacement and the axial displacement of the edge inductive sensor 103 based on the magnetic bearing controller.

[0051] It can be understood that the radial and axial position sensor probes are three stators sleeved in parallel outside the measured rotating shaft. The middle stator is opposite to the center position of the rotor for radial position detection, and the two side stators are symmetric to each other for axial position detection.

[0052] In addition, in some embodiments, the stator for radial displacement detection has a toroidal core 403 with a toothed probe, and coils are wound around the toothed probe. There are a total of 4 groups, which are evenly distributed along the circumference. The two opposite groups of probe coils are connected in a differential manner to respectively measure the position changes in the X and Y directions of the rotating shaft. The change in the radial displacement can be expressed as: , , where They are the changes in the displacements in the X and Y directions (both the X and Y directions are radial directions) when the rotor moves radially, They are the change amounts of the inductances of the probe coils connected differentially in the X and Y directions, δ is the initial air gap size, A is the equivalent magnetic pole area, μ is the air gap magnetic permeability, N is the total number of turns of each group of probe coils; the two stators for axial displacement detection are circular iron cores 403 with toothed probes. Coils are wound around the toothed probes, and there are a total of 4 groups, evenly distributed along the circumference. The windings on each stator are connected in series, and the coils on the two stators are connected in a differential manner to measure the change in the position of the rotating shaft in the Z direction. The axial displacement change can be expressed as: , where Δz is the change in the displacement in the Z direction when the rotor moves axially, ΔLz is the change amount of the inductance of the probe coil connected differentially in the Z direction, and c is the equivalent tooth width of the stator probe.

[0053] In addition, the numerical fitting method includes the following steps: (1) Fit the influence of the radial displacements in the X and Y directions on the winding inductance under the same axial displacement; (2) Fit the influence of the displacements in the X, Y, and Z directions on the axial inductance using the influence rules of X and Y on the axial coil inductance.

[0054] Furthermore, observing the inductance data of the axial sensor during simulation, it can be seen that whether the displacement of the sensor target in the X and Y directions is in the positive direction or the negative direction, the influence on the inductance change of the axial sensor is the same.

[0055] First, fit the influence of X and Y on the inductance of its axial sensor coil under the same Z displacement: ; where x, y x and y are the coordinates of the X-axis and Y-axis respectively, and a and b are the coefficients obtained by fitting.

[0056] Then, using x, y the influence rule of on the axial coil inductance, fit the influence of X, Y, and Z on it: ; where z z is the coordinate of the Z-axis, and a, b, c, and d are the coefficients obtained by fitting.

[0057] Figure 5 It is the fitting formula of the axial inductance of the large-gap edge inductive sensor 103 with respect to the displacements in the X, Y, and Z directions. Among them: the X-axis is the sum of the squares of the actual radial displacements: , the Y-axis is the actual axial displacement z, and the Z-axis is the axial inductance L Z .

[0058] Through radial-axial non-linear fitting, the coupling situation of the radial displacement of the edge inductive sensor 103 to the axial displacement detection can be effectively solved, and the detection accuracy can be improved.

[0059] The present invention also provides a method for non-linearly decoupling the radial and axial directions of an edge inductive sensor. The method is applied to the above-mentioned device, as Figure 6 shown, the method includes: S601. Output an excitation signal from a signal excitation source to the radial displacement sensor and the axial displacement sensor of the edge inductive sensor; S602. Based on the signal processing unit and according to the feedback signal output by the radial displacement sensor, extract a first electrical signal for characterizing the radial displacement, and based on the feedback signal output by the axial displacement sensor, extract a second electrical signal for characterizing the axial displacement; S603. Based on the digital control unit and according to the first electrical signal, the second electrical signal and the coupling model of the edge inductive sensor, fit the influence law of different radial displacements on the output signal of the axial displacement sensor, and perform non-linear decoupling of the radial displacement and the axial displacement based on the influence law.

[0060] Those skilled in the art can understand that all or part of the processes for implementing the methods of the above embodiments can be completed by instructing relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. Among them, the computer-readable storage medium is a magnetic disk, an optical disk, a read-only memory or a random access memory, etc.

[0061] The above has introduced in detail the device and method for non-linearly decoupling the radial and axial directions of the edge inductive sensor provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A radial and axial nonlinear decoupling device for an edge inductive sensor, characterized in that: include: A signal excitation source, used for outputting excitation signals to the radial displacement sensor and the axial displacement sensor of the edge inductive sensor; a signal processing unit, configured to extract a first electrical signal for characterizing radial displacement based on a feedback signal output by the radial displacement sensor, and to extract a second electrical signal for characterizing axial displacement based on a feedback signal output by the axial displacement sensor; The digital control unit is used to fit the influence of different radial displacements on the output signal of the axial displacement sensor based on the first electrical signal, the second electrical signal and the coupling model of the edge inductive sensor, and perform nonlinear decoupling of the radial displacement and the axial displacement based on the influence law.

2. The radial and axial nonlinear decoupling device of the edge inductive sensor according to claim 1, characterized in that: The signal excitation source comprises: Crystal oscillator, used to output the original excitation signal; A filtering circuit, used for filtering the original excitation signal to obtain a filtered signal; The reverse amplification circuit is used to reversely amplify the filtered signal to obtain a sine excitation signal or a cosine excitation signal.

3. The radial and axial nonlinear decoupling device of the edge inductive sensor according to claim 1, characterized in that: The signal processing unit comprises: A filtering and detection circuit, used for filtering and detecting the feedback signal and then outputting a DC voltage signal; The demodulation unit is used to extract a first electrical signal for characterizing a radial displacement of the edge inductive sensor and a second electrical signal for characterizing an axial displacement of the edge inductive sensor based on the DC voltage signal.

4. The radial and axial nonlinear decoupling device of the edge inductive sensor according to claim 3, characterized in that: The filtering and detection circuit comprises: a first signal amplifying unit, configured to receive the feedback signal and the reference signal, and amplify the feedback signal and the reference signal respectively; A differential unit, used for performing differential processing on the amplified feedback signal and the reference signal to obtain a differential signal; The second signal amplifying unit is used to amplify the differential signal to obtain a DC voltage signal.

5. The radial and axial nonlinear decoupling device of the edge inductive sensor according to claim 4, characterized in that: The first signal amplifying unit includes: a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a second capacitor, a third capacitor, a first diode and a second diode; The positive input terminal of the first operational amplifier receives a feedback signal through the first resistor, the output terminal of the first operational amplifier outputs through the second resistor and the first diode connected in series, and the second capacitor and the third capacitor are respectively connected to two intermediate stages of the first operational amplifier; The positive input terminal of the second operational amplifier is connected to the reference signal through the third resistor, and the output terminal of the second operational amplifier is output through the fourth resistor and the second diode connected in series.

6. The radial and axial nonlinear decoupling device of the edge inductive sensor according to claim 5, characterized in that: The first signal amplifying unit further includes: a fifth resistor and a first capacitor; The fifth resistor and the first capacitor form a low-pass filter unit connected to the first resistor.

7. The radial and axial nonlinear decoupling device of the edge inductive sensor according to claim 4, characterized in that: The differential unit includes: a sixth resistor and a seventh resistor connected in series, and a fourth capacitor and a fifth capacitor connected in series; the sixth resistor and the seventh resistor connected in series are connected in parallel with the fourth capacitor and the fifth capacitor connected in series.

8. The radial and axial nonlinear decoupling device of the edge inductive sensor according to claim 4, characterized in that: The second signal amplifying unit includes: a third operational amplifier, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor and a tenth capacitor; The positive input terminal of the third operational amplifier is connected to the differential unit through the eighth resistor, and the negative input terminal of the third operational amplifier is connected to the differential unit through the ninth resistor; The eighth capacitor and the ninth capacitor are respectively connected to two intermediate stages of the third operational amplifier; The tenth resistor and the sixth capacitor are both connected in parallel between the positive input terminal and the output terminal of the third operational amplifier; The eleventh resistor and the seventh capacitor are connected in parallel between the negative input terminal and the output terminal of the third operational amplifier; The output end of the third operational amplifier is grounded through the twelfth resistor and the thirteenth resistor in sequence, and the tenth capacitor is connected in parallel with the thirteenth resistor.

9. The radial and axial nonlinear decoupling device of an edge inductive sensor according to any one of claims 1 to 8, characterized in that: The edge inductive sensor comprises: three layers of iron core; the middle layer of the three layers of iron core and the coil fixed on the middle layer of the iron core constitute a radial displacement sensor, and the upper and lower layers of the three layers of iron core and the coils fixed on the upper and lower layers of the iron core respectively constitute an axial displacement sensor.

10. A radial and axial nonlinear decoupling method for an edge inductive sensor, characterized in that: The method is applied to the device according to any one of claims 1 to 9, and the method comprises: A radial displacement sensor and an axial displacement sensor that output excitation signals to edge inductive sensors based on a signal excitation source; Extracting a first electrical signal for characterizing radial displacement based on a signal processing unit and according to a feedback signal output by the radial displacement sensor, and extracting a second electrical signal for characterizing axial displacement based on a feedback signal output by the axial displacement sensor; Based on a digital control unit and according to a coupling model of the first electrical signal, the second electrical signal and an edge inductive sensor, the influence of different radial displacements on the output signal of the axial displacement sensor is fitted, and nonlinear decoupling of the radial displacement and the axial displacement is performed based on the influence law.

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