An ultra-precision lathe spindle unbalance vibration signal processing method and system

Abstract

This invention belongs to the field of signal processing technology and provides a method and system for processing unbalanced vibration signals of an ultra-precision lathe spindle. The method includes: synchronously acquiring the X-axis grating follower error signal and the spindle encoder pulse signal using an ultra-precision lathe X-axis grating ruler and a spindle encoder; extracting the weak unbalance signal using a quadrature lock-in amplifier; synchronizing the quadrature reference signal with the real-time spindle angle; mixing the quadrature reference signal with the X-axis grating follower error signal; filtering the signal using a zero-phase-shift filter to obtain the DC component; and calculating the amplitude and phase of the unbalance signal; processing the amplitude and phase of the unbalance signal using the influence coefficient method to obtain the anchoring quality and angle for leveling the spindle dynamic balance. This invention can conveniently monitor changes in spindle dynamic balance, reduce the cost of spindle dynamic balance adjustment, improve the efficiency of spindle dynamic balance adjustment, and accurately calculate the phase information of the spindle unbalance.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and in particular to a method and system for processing unbalanced vibration signals of an ultra-precision lathe spindle. Background Technology

[0002] Ultra-precision machining is an important indicator of a country's high-end manufacturing capabilities, aiming to achieve nanometer-level machining accuracy and mirror-like surface quality. For ultra-precision lathes, the spindle, as the core component driving the workpiece's rotational motion, has dynamic performance, especially rotational smoothness, which is one of the fundamental factors determining the final machining quality.

[0003] When a spindle rotates at high speed, even a tiny imbalance will generate periodic excitation forces, causing micro-vibrations in the spindle system. These vibrations are directly reproduced on the machined surface, forming ripples synchronized with the rotational speed, severely damaging the surface roughness and shape accuracy of the workpiece. Therefore, precise dynamic balancing of the ultra-precision spindle is a prerequisite for ensuring it meets design performance specifications and achieving ultra-precision machining. The key to achieving spindle dynamic balancing is extracting the weak imbalance vibration signal and accurately calculating its amplitude and phase. However, in the dynamic balancing process, the imbalance vibration signal is often overwhelmed by noise, making it difficult for ordinary signal processing algorithms to accurately extract it. Summary of the Invention

[0004] This invention provides a method and system for processing unbalanced vibration signals of an ultra-precision lathe spindle to solve the problems mentioned in the background art.

[0005] In a first aspect, the present invention provides a method for processing unbalanced vibration signals of an ultra-precision lathe spindle, comprising: The X-axis grating ruler and spindle encoder of an ultra-precision lathe are used to synchronously acquire the X-axis grating following error signal and the spindle encoder pulse signal; Weak unbalanced signals are extracted using a quadrature lock-in amplifier. The quadrature reference signal is synchronized with the real-time angle of the main shaft. After mixing with the X-axis grating follower error signal, the DC component is obtained after filtering with a zero-phase-shift filter. The amplitude and phase of the unbalanced signal are then calculated. The amplitude and phase of the unbalanced signal are processed using the influence coefficient method to obtain the nailing quality and angle for dynamic balancing of the leveling spindle.

[0006] Furthermore, the method of synchronously acquiring the X-axis grating following error signal and the spindle encoder pulse signal using an ultra-precision lathe X-axis grating ruler and a spindle encoder includes: Using the acquisition function of the CNC system of the ultra-precision lathe, the actual position signal Act(t) and the command position signal Cmd(t) of the X-axis grating of the ultra-precision lathe, as well as the spindle encoder pulse signal, are synchronously acquired at a fixed sampling frequency Fs, and the following error signal Err(t) of the X-axis grating is calculated.

[0007] Furthermore, the method also includes: The real-time angular position sequence θ(t) of the spindle is decoded from the spindle encoder pulse signal. The following error signal Err(t) is then cut into an integer cycle following error signal S(t) using θ(t). At the same time, θ(t) is also cut into θ'(t).

[0008] Furthermore, the quadrature lock-in amplifier generates two orthogonal reference signals, including a co-directional reference signal and a quadrature reference signal; the co-directional reference signal is Ref_I(t)=sin(θ'(t)); the quadrature reference signal is Ref_Q(t)=cos(θ'(t)).

[0009] Furthermore, the method also includes: The integer-cycle follower error signal S(t) is multiplied by the two reference signals to obtain two mixing signals: Mix_I(t)=S(t)×Ref_I(t) and Mix_Q(t)=S(t)×Ref_Q(t).

[0010] Furthermore, the process of obtaining the DC component after filtering using a zero-phase-shift filter includes: The two mixing signals Mix_I(t) and Mix_Q(t) are subjected to zero-phase-shift filtering respectively. After filtering, the high-frequency components are removed, and the DC components are obtained: X=ZPF(Mix_I(t)) and Y=ZPF(Mix_Q(t)).

[0011] Further, the calculation of the amplitude and phase of the unbalanced signal includes: Based on the filtered DC components X and Y, the amplitude A and phase of the unbalanced vibration signal in the original signal are calculated. A = 2 × sqrt(X² + Y²) =arctan(Y / X).

[0012] Secondly, the present invention provides a signal processing system for unbalanced vibration of an ultra-precision lathe spindle, comprising: The acquisition module is used to synchronously acquire the X-axis grating tracking error signal and the spindle encoder pulse signal using the X-axis grating ruler and spindle encoder of an ultra-precision lathe. The calculation module is used to extract weak unbalanced signals using a quadrature lock-in amplifier. The quadrature reference signal is synchronized with the real-time angle of the main shaft. After mixing with the X-axis grating follower error signal, the DC component is obtained after filtering with a zero-phase-shift filter, and the amplitude and phase of the unbalanced signal are calculated. The processing module is used to process the amplitude and phase of the unbalanced signal using the influence coefficient method, thereby obtaining the nailing quality and angle for the dynamic balancing of the leveling spindle.

[0013] Thirdly, the present invention provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the ultra-precision lathe spindle unbalanced vibration signal processing method as described above.

[0014] Fourthly, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the ultra-precision lathe spindle unbalanced vibration signal processing method as described above. The method for processing unbalanced vibration signals of an ultra-precision lathe spindle provided in the first aspect of this invention has the following beneficial effects: This invention utilizes the built-in optical grating and encoder of the ultra-precision lathe spindle, replacing the spindle vibration signal with the X-axis optical grating tracking error signal and reflecting the real-time spindle angle information with encoder pulse signals. It requires no external equipment, does not affect normal machine tool processing, facilitates monitoring of spindle dynamic balance changes, reduces the cost of spindle dynamic balance adjustment, and improves the efficiency of spindle dynamic balance adjustment. This invention applies digital lock-in amplifier technology based on real-time angle feedback to spindle dynamic balance adjustment, dynamically generating a reference signal using high-resolution real-time angle data output from the spindle encoder. This achieves real-time synchronization between the reference signal and the actual physical motion, accurately calculating the phase information of the spindle imbalance.

[0015] It is understood that the beneficial effects of the second, third and fourth aspects mentioned above can be found in the relevant descriptions in the first aspect above, and will not be repeated here. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 A flowchart of a method for processing unbalanced vibration signals of an ultra-precision lathe spindle provided in an embodiment of the present invention; Figure 2 This is a time-domain diagram of the original signal of the grating following error provided in an embodiment of the present invention; Figure 3 The original signal spectrum of the grating following error provided in the embodiments of the present invention; Figure 4 This is a time-domain image of the target signal after decomposition of the grating following error provided in an embodiment of the present invention; Figure 5 The target signal spectrum after grating following error decomposition is provided in an embodiment of the present invention. Detailed Implementation

[0018] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0019] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0020] Furthermore, in the description of this invention and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0021] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of the invention include a particular feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. "A plurality" means "two or more."

[0022] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0023] This invention provides a method for processing unbalanced vibration signals from an ultra-precision lathe spindle, such as... Figure 1 As shown, the process includes the following steps: Simultaneously acquiring the X-axis grating following error signal and the spindle encoder pulse signal using an ultra-precision lathe X-axis grating ruler and spindle encoder; extracting the weak unbalance signal using an orthogonal lock-in amplifier, synchronizing the orthogonal reference signal with the real-time spindle angle, mixing it with the X-axis grating following error signal, filtering it with a zero-phase-shift filter to obtain the DC component, and calculating the amplitude and phase of the unbalance signal; processing the amplitude and phase of the unbalance signal using the influence coefficient method to obtain the nailing quality and angle for leveling the spindle dynamic balancing.

[0024] In some embodiments, the method of synchronously acquiring the X-axis grating following error signal and the spindle encoder pulse signal using the X-axis grating ruler and spindle encoder of the ultra-precision lathe includes: using the acquisition function of the CNC system of the ultra-precision lathe to synchronously acquire the actual position signal Act(t) and the command position signal Cmd(t) of the X-axis grating of the ultra-precision lathe and the spindle encoder pulse signal at a fixed sampling frequency Fs, and calculating the following error signal Err(t) of the X-axis grating.

[0025] In some embodiments, the method further includes: decoding the real-time angular position sequence θ(t) of the spindle based on the spindle encoder pulse signal, using θ(t) to cut the following error signal Err(t) into an integer cycle following error signal S(t), and θ(t) is also cut into θ'(t).

[0026] In some embodiments, the quadrature lock-in amplifier generates two orthogonal reference signals, including a co-directional reference signal and a quadrature reference signal; the co-directional reference signal is Ref_I(t)=sin(θ'(t)); the quadrature reference signal is Ref_Q(t)=cos(θ'(t)).

[0027] In some embodiments, the method further includes: multiplying the integer-cycle follower error signal S(t) with two reference signals respectively to obtain two mixing signals: Mix_I(t)=S(t)×Ref_I(t) and Mix_Q(t)=S(t)×Ref_Q(t).

[0028] In some embodiments, obtaining the DC component by filtering with a zero-phase-shift filter includes: performing zero-phase-shift filtering on the two mixing signals Mix_I(t) and Mix_Q(t) respectively, and after filtering, removing the high-frequency components to obtain the DC components: X=ZPF(Mix_I(t)) and Y=ZPF(Mix_Q(t)).

[0029] In some embodiments, calculating the amplitude and phase of the unbalanced signal includes: calculating the amplitude A and phase of the unbalanced vibration signal in the original signal based on the filtered DC components X and Y. A = 2 × sqrt(X² + Y²) =arctan(Y / X).

[0030] To achieve accurate extraction of spindle unbalanced vibration signals, this invention employs quadrature lock-in amplifier technology based on real-time angle feedback.

[0031] First, utilizing the acquisition function of the ultra-precision lathe CNC system, the actual position signal Act(t) and the command position signal Cmd(t) of the ultra-precision lathe X-axis grating, as well as the spindle encoder pulse signal, are synchronously acquired at a fixed sampling frequency Fs. Further, the following error signal Err(t) of the X-axis grating can be calculated, reflecting the vibration state of the spindle. Based on the spindle encoder pulse signal, the real-time spindle angular position sequence θ(t) can be decoded. Using θ(t), the following error signal Err(t) can be segmented into an integer-cycle following error signal S(t), and simultaneously, θ(t) is also segmented into θ'(t).

[0032] Unlike the sin(2πft) model of traditional quadrature lock-in amplifiers, this invention generates the following two orthogonal reference signals. Ref_I(t)=sin(θ'(t))——(Same-direction reference signal) Ref_Q(t)=cos(θ'(t))——(orthogonal reference signal) Here, θ(t) is not a time-based linear growth function, but rather an actual measurement from the physical hardware. Regardless of spindle speed variations or jitter, Ref_I(t) and Ref_Q(t) will accurately reflect the current phase state at each sampling instant.

[0033] Multiplying the full-cycle follower error signal S(t) by the two reference signals respectively yields two mixing signals: Mix_I(t) = S(t) × Ref_I(t) Mix_Q(t) = S(t) × Ref_Q(t) The two mixing signals, Mix_I(t) and Mix_Q(t), are subjected to zero-phase-shift filtering to avoid the phase delay caused by traditional IIR filters. After filtering, high-frequency components (second harmonic components) are removed, and the DC component is obtained.

[0034] X=ZPF(Mix_I(t))——(DC value of the same-direction component) Y=ZPF(Mix_Q(t))——(DC value of the quadrature component) Based on the filtered DC components X and Y, the amplitude A and phase of the unbalanced vibration signal in the original signal can be calculated. : Amplitude: A = 2 × sqrt(X² + Y²) Phase: =arctan(Y / X) The time-domain plot of the original signal of the grating following error is as follows Figure 2 As shown, the spectrum of the original signal of the grating following error is as follows: Figure 3 As shown, the time-domain plot of the target signal after decomposition of the grating following error is as follows: Figure 4 As shown, the spectrum of the target signal after decomposition of the grating following error is as follows: Figure 5 As shown.

[0035] Compared with the prior art, the advantages of this invention are: Advantage 1: This invention fully utilizes the built-in optical grating and encoder of the ultra-precision lathe spindle, replacing the spindle vibration signal with the X-axis optical grating following error signal, and using the encoder pulse signal to reflect the real-time angle information of the spindle. No external equipment is required, and it will not affect the normal processing of the machine tool. It can conveniently monitor changes in spindle dynamic balance, reduce the cost of spindle dynamic balance adjustment, and improve the efficiency of spindle dynamic balance adjustment.

[0036] Advantage 2: This invention applies digital lock-in amplifier technology based on real-time angle feedback to spindle dynamic balance adjustment. It uses high-resolution real-time angle data output by the spindle encoder to dynamically generate a reference signal, thereby achieving real-time synchronization between the reference signal and the actual physical motion, and accurately calculating the phase information of the spindle imbalance.

[0037] Corresponding to the ultra-precision lathe spindle unbalanced vibration signal processing method described in the above embodiments, this invention also provides an ultra-precision lathe spindle unbalanced vibration signal processing system, which includes: The acquisition module is used to synchronously acquire the X-axis grating tracking error signal and the spindle encoder pulse signal using the X-axis grating ruler and spindle encoder of an ultra-precision lathe. The calculation module is used to extract weak unbalanced signals using a quadrature lock-in amplifier. The quadrature reference signal is synchronized with the real-time angle of the main shaft. After mixing with the X-axis grating follower error signal, the DC component is obtained after filtering with a zero-phase-shift filter, and the amplitude and phase of the unbalanced signal are calculated. The processing module is used to process the amplitude and phase of the unbalanced signal using the influence coefficient method, thereby obtaining the nailing quality and angle for the dynamic balancing of the leveling spindle.

[0038] It should be noted that the information interaction and execution process between the above modules / units are based on the same concept as the method embodiments of the present invention. For details on their specific functions and technical effects, please refer to the method embodiments section, which will not be repeated here.

[0039] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this invention. The specific working process of the units and modules in the above device can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0040] This invention also provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the ultra-precision lathe spindle unbalanced vibration signal processing method provided in the first aspect.

[0041] In applications, terminal devices may include, but are not limited to, processors and memory. These are merely examples of terminal devices and do not constitute a limitation on them. They may include more or fewer components, combinations of certain components, or different components, such as input / output devices and network access devices. Input / output devices may include cameras, audio capture / playback devices, displays, etc. Network access devices may include network modules for wireless network communication with external devices.

[0042] In applications, the processor can be a Central Processing Unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0043] In applications, the memory may be an internal storage unit of the terminal device in some embodiments, such as the hard drive or RAM of the terminal device. In other embodiments, the memory may be an external storage device of the terminal device, such as a plug-in hard drive, a smart media card (SMC), or a flash card. The memory may also include both internal and external storage units of the terminal device. The memory is used to store the operating system, applications, boot loader, data, and other programs, such as the program code of a computer program. The memory can also be used to temporarily store data that has been output or will be output.

[0044] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement the steps in the above-described method embodiments.

[0045] The present invention implements all or part of the processes in the methods of the above embodiments by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to a terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, such as a USB flash drive, a portable hard drive, a magnetic disk, or an optical disk.

[0046] Those skilled in the art will recognize that the device and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0047] In the embodiments provided by this invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be through some interfaces, or indirect couplings or communication connections between devices, and may be electrical, mechanical, or other forms.

[0048] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for processing unbalanced vibration signals of an ultra-precision lathe spindle, characterized in that, include: The X-axis grating ruler and spindle encoder of an ultra-precision lathe are used to synchronously acquire the X-axis grating following error signal and the spindle encoder pulse signal; Weak unbalanced signals are extracted using a quadrature lock-in amplifier. The quadrature reference signal is synchronized with the real-time angle of the main shaft. After mixing with the X-axis grating follower error signal, the DC component is obtained after filtering with a zero-phase-shift filter. The amplitude and phase of the unbalanced signal are then calculated. The amplitude and phase of the unbalanced signal are processed using the influence coefficient method to obtain the nailing quality and angle for dynamic balancing of the leveling spindle.

2. The method for processing unbalanced vibration signals of an ultra-precision lathe spindle as described in claim 1, characterized in that, The method of synchronously acquiring the X-axis grating tracking error signal and the spindle encoder pulse signal using an ultra-precision lathe X-axis grating ruler and a spindle encoder includes: Using the acquisition function of the CNC system of the ultra-precision lathe, the actual position signal Act(t) and the command position signal Cmd(t) of the X-axis grating of the ultra-precision lathe, as well as the spindle encoder pulse signal, are synchronously acquired at a fixed sampling frequency Fs, and the following error signal Err(t) of the X-axis grating is calculated.

3. The method for processing unbalanced vibration signals of an ultra-precision lathe spindle as described in claim 2, characterized in that, The method further includes: The real-time angular position sequence θ(t) of the spindle is decoded from the spindle encoder pulse signal. The following error signal Err(t) is then cut into an integer cycle following error signal S(t) using θ(t). At the same time, θ(t) is also cut into θ'(t).

4. The method for processing unbalanced vibration signals of an ultra-precision lathe spindle as described in claim 3, characterized in that, The quadrature lock-in amplifier generates two orthogonal reference signals, including a co-directional reference signal and a quadrature reference signal; the co-directional reference signal is Ref_I(t)=sin(θ'(t)); the quadrature reference signal is Ref_Q(t)=cos(θ'(t)).

5. The method for processing unbalanced vibration signals of an ultra-precision lathe spindle as described in claim 4, characterized in that, The method further includes: The integer-cycle follower error signal S(t) is multiplied by the two reference signals to obtain two mixing signals: Mix_I(t)=S(t)×Ref_I(t) and Mix_Q(t)=S(t)×Ref_Q(t).

6. The method for processing unbalanced vibration signals of an ultra-precision lathe spindle as described in claim 5, characterized in that, The process of obtaining the DC component after filtering using a zero-phase-shift filter includes: The two mixing signals Mix_I(t) and Mix_Q(t) are subjected to zero-phase-shift filtering respectively. After filtering, the high-frequency components are removed, and the DC components are obtained: X=ZPF(Mix_I(t)) and Y=ZPF(Mix_Q(t)).

7. The method for processing unbalanced vibration signals of an ultra-precision lathe spindle as described in claim 6, characterized in that, The calculation of the amplitude and phase of the unbalanced signal includes: Based on the filtered DC components X and Y, the amplitude A and phase of the unbalanced vibration signal in the original signal are calculated. A = 2 × sqrt(X² + Y²) =arctan(Y / X).

8. A signal processing system for unbalanced vibration of an ultra-precision lathe spindle, characterized in that, include: The acquisition module is used to synchronously acquire the X-axis grating tracking error signal and the spindle encoder pulse signal using the X-axis grating ruler and spindle encoder of an ultra-precision lathe; The calculation module is used to extract weak unbalanced signals using a quadrature lock-in amplifier. The quadrature reference signal is synchronized with the real-time angle of the main shaft. After mixing with the X-axis grating follower error signal, the DC component is obtained after filtering with a zero-phase-shift filter, and the amplitude and phase of the unbalanced signal are calculated. The processing module is used to process the amplitude and phase of the unbalanced signal using the influence coefficient method, thereby obtaining the nailing quality and angle for the dynamic balancing of the leveling spindle.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the ultra-precision lathe spindle unbalanced vibration signal processing method as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the ultra-precision lathe spindle unbalanced vibration signal processing method as described in any one of claims 1 to 7.

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