A method and device for active control of multi-frequency vibration of helicopters with adaptive dual notch filters

Abstract

This invention provides a method and apparatus for active multi-frequency vibration control of helicopters using adaptive dual notch filters. The method includes: step 1, achieving notch response separation through reference signal synthesis, a notch response separator, and an adaptive separation algorithm; step 2, achieving notch control through reference signal synthesis, a notch controller, and an adaptive control algorithm. This invention effectively improves the multi-frequency vibration control performance of helicopter structures, increases the convergence speed of multi-frequency control, and reduces the computational load of multi-frequency multi-channel control.

Description

Technical Field

[0001] This invention belongs to the field of active vibration control for helicopters, and particularly relates to a method and device for active control of multi-frequency vibration of helicopters with adaptive dual notch filters. Background Technology

[0002] Helicopter vibration is a prominent issue. Sustained high-level vibration not only severely deteriorates the working environment for crew and equipment but also impacts the helicopter's structural fatigue and flight safety. Reducing helicopter vibration levels is one of the most important issues in the helicopter field. Active control of helicopter structural response, characterized by strong adaptability, good control performance, and low added mass, has become a crucial development direction in helicopter vibration control. The control algorithm is the core of the active vibration control system. Since helicopter vibration is primarily composed of the rotor passage frequency NΩ and its higher harmonics, multi-frequency control is required in the control algorithm. Current control algorithms, while aiming for multi-frequency control, do not consider the superposition of frequencies in the error signal, leading to reduced control performance. Summary of the Invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing an adaptive dual notch filter multi-frequency vibration active control method for helicopters. The method utilizes an adaptive dual notch filter for response separation and control, and constructs an adaptive notch filter controller and a response separator respectively. Based on the least mean square algorithm, the notch filter controller improves the convergence speed of the control algorithm, and the notch filter response separator separates the frequency components of each order in the control error response, thereby achieving independent control of each order of harmonics in the time domain and improving control performance and convergence speed.

[0004] The method of the present invention includes the following steps:

[0005] Step 1: Notch response separation is achieved through reference signal synthesis, notch response separator, and adaptive separation algorithm;

[0006] Step 2: Notch control is implemented through reference signal synthesis, notch controller, and adaptive control algorithm.

[0007] Step 1 includes:

[0008] Step 101: Determine the number of rotor blades N based on the characteristics of the helicopter rotor;

[0009] Step 102: Obtain the rotor speed signal Ω from the rotor excitation f(n), and obtain the rotor passing frequency NΩ and its higher-order harmonics iNΩ, where i = 1, 2, ..., R, and R is the harmonic order to be controlled;

[0010] Step 103: Construct the i-th order frequency reference signal x of the notch filter response separator based on the harmonic frequency iNΩ. i(n)=[sin(iNΩn) cos(iNΩn)], x i (n) contains two reference signals, a sine and a cosine, where n is a discrete-time variable;

[0011] Step 104, Notch Response Separator for Harmonic Frequency iNΩ Includes 2 response separation parameters Corresponding to sine and cosine respectively, they are represented as Initialize T denotes matrix transpose;

[0012] Step 105: Obtain the control error e(n) which includes the superposition of multiple harmonic responses;

[0013] Step 106, based on the reference signal x i (n), after notch response separator Generate the notch response separation signal for the i-th harmonic frequency

[0014] Step 107: Calculate the separation error of the control error e(n) after notch response separation.

[0015] Step 108, notch response separator The parameters are iterated.

[0016] In step 107, the control error e(n) is calculated using the following formula, which is the separation error after notch filter response separation.

[0017]

[0018] In step 108, the notch response separator The parameter iteration is implemented using the Least Mean Square (LMS) algorithm, which utilizes the notch response separator parameters from the previous time step. Separation error and reference signal x i (n) Iterates, and the notch response separator at the next time step The parameter formula is:

[0019]

[0020] in This is the correction step size for the notch response separator parameters.

[0021] Step 2 includes:

[0022] Step 201: Construct the i-th order frequency reference signal x of the notch filter controller based on the harmonic frequency iNΩ.i (n)=[sin(iNΩn) cos(iNΩn)], x i (n) contains two reference signals, a sine and a cosine, where n is a discrete-time variable;

[0023] Step 202, control channel estimation H c ′ is a finite impulse response model established based on the control channel, and the control channel estimates H. c The length of ′ is N c The notch control reference signal x at the i-th order frequency i (n) H needs to be estimated through the control channel. c Pre-filtering generates a pre-filtered reference signal.

[0024] Step 203, notch filter controller w for harmonic frequency iNΩ i (n) contains 2 control parameters w i s (n), w i c (n), corresponding to sine and cosine respectively, denoted as w i (n)=[w i s (n) w i c (n)] T Assign initial value w i (n) = [0 0] T ;

[0025] Step 204, based on the reference signal x i (n), controlled by the notch filter controller parameter w i (n), the control signal u that generates the i-th harmonic. i (n)=w i (n)x i (n);

[0026] Step 205: The control signals of each harmonic order are superimposed to form the control signal u(n).

[0027] Step 206, the rotor excitation f(n) passes through the main channel H p (n) is transmitted to the helicopter body, generating a body vibration response d(n);

[0028] Step 207, the control signal u(n) passes through the control channel H c This generates a control response y(n) = H c u(n);

[0029] Step 208: The body vibration response d(n) and the control response y(n) are superimposed to form the control error e(n);

[0030] Step 209, adjust the notch filter controller parameters w i Iterate over the parameters of (n).

[0031] In step 208, the control error e(n) is calculated using the following formula:

[0032] e(n) = d(n) - y(n),

[0033] but

[0034] In step 209, the notch filter controller parameter w i The parameter iteration of (n) is implemented using the Least Mean Square (LMS) algorithm, which utilizes the notch filter parameters w(n) and control error from the previous time step. and pre-filtered reference signal x i Iterate through ′(n) to obtain the notch controller parameters w at the next time step. i The formula for the parameter (n+1) is:

[0035] w i (n+1)=w i (n)+2μ i e i (n)x′ i (n),

[0036] Where μ i This is the correction step size for the notch filter controller parameters.

[0037] Furthermore, the present invention also provides a helicopter adaptive dual notch filter multi-frequency vibration active control device, characterized in that it includes a notch filter response separation module and a notch filter control module.

[0038] The notch response separation module is used to achieve notch response separation through reference signal synthesis, notch response separator and adaptive separation algorithm;

[0039] The notch control module is used to implement notch control through reference signal synthesis, a notch controller, and an adaptive control algorithm.

[0040] The present invention has the following beneficial effects:

[0041] (1) By using a notch filter response separator, signals of different frequencies in the response to be controlled can be separated for independent control to eliminate mutual interference and improve the control capability of the control system to control multi-frequency responses.

[0042] (2) By using a notch filter controller, the real-time tracking capability of vibration response changes is enhanced, and the convergence speed of adaptive control is improved. Attached Figure Description

[0043] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0044] Figure 1 This is a schematic diagram of the method of the present invention.

[0045] Figure 2 The technical solution provided by this invention is shown in the control effect diagram under three-frequency steady-state harmonic excitation. Detailed Implementation

[0046] like Figure 1 As shown, the present invention provides an active control method for multi-frequency vibration of helicopters based on adaptive dual notch filters, which consists of notch filter response separation and notch filter control;

[0047] Step 1, the notch response separation is achieved by reference signal synthesis, notch response separator and adaptive separation algorithm;

[0048] Step 101: Determine the number of rotor blades N based on the characteristics of the helicopter rotor;

[0049] Step 102: Obtain the rotor speed signal Ω from the rotor excitation f(n), and obtain the rotor passing frequency NΩ and its higher-order harmonics iNΩ, where i = 1, 2, ..., R, and R is the order of the harmonics to be controlled, which is determined by the controller design requirements. The optional R = 3.

[0050] Step 103: Construct the i-th order frequency reference signal x of the notch filter response separator based on the harmonic frequency iNΩ. i (n)=[sin(iNΩn) cos(iNΩn)], x i (n) contains two reference signals, a sine and a cosine, where n is a discrete-time variable;

[0051] Step 104, Notch Response Separator for Harmonic Frequency iNΩ It contains two response separation parameters, corresponding to the sine and cosine respectively, denoted as: Initialize

[0052] Step 105 includes the control error response e(n) of the superposition of multiple harmonic responses;

[0053] Step 106, based on the reference signal x i (n), parameters separated by a notch response separator Generate the notch response separation signal for the i-th harmonic frequency

[0054] Step 107, It is the control error e(n) separated by notch filtering response.

[0055] Step 108, Notch Response Separator The parameter iteration is implemented using the Least Mean Square (LMS) algorithm, which utilizes the notch filter parameters from the previous time step. Separation error and reference signal x i (n) is iterated, and the parameter formula for the next time step is:

[0056]

[0057] in This is the correction step size for the notch response separator parameters;

[0058] Step 2, the notch control is implemented by reference signal synthesis, notch controller and adaptive control algorithm;

[0059] Step 201: Construct the i-th order frequency reference signal x of the notch filter controller based on the harmonic frequency iNΩ. i (n)=[sin(iNΩn) cos(iNΩn)], x i (n) contains two reference signals, a sine and a cosine, where n is a discrete-time variable;

[0060] Step 202, control channel estimation H c ′ is a finite impulse response model established based on the control channel, and its length is N. c The notch control reference signal x at the i-th order frequency i (n), H needs to be estimated through the control channel. c Pre-filtering generates a pre-filtered reference signal.

[0061] Step 203, notch filter controller w for harmonic frequency iNΩ i (n) contains two control parameters corresponding to the sine and cosine respectively, denoted as w. i (n)=[w i s (n) w i c (n)] T Assign initial values ​​[0 0] T ;

[0062] Step 204, based on the reference signal x i (n), controlled by the notch filter controller parameter wi (n), the control signal u that generates the i-th harmonic. i (n)=w i (n)x i (n);

[0063] Step 205: The control signals of each harmonic order are superimposed to form a control signal.

[0064] Step 206, the rotor excitation f(n) passes through the main channel H p (n) is transmitted to the helicopter body, generating a body vibration response d(n);

[0065] Step 207, the control signal u(n) passes through the control channel H c This generates a control response y(n) = H c u(n);

[0066] Step 208, the body vibration response d(n) and the control response y(n) are superimposed to form the control error e(n), e(n) = d(n) - y(n), therefore

[0067] Step 209, notch controller parameters w i The parameter iteration of (n) is implemented using the Least Mean Square (LMS) algorithm, which utilizes the notch filter parameters w(n) and control error from the previous time step. and pre-filtered reference signal x i The parameter formula for the next time step of iterating through ′(n) is:

[0068] w i (n+1)=w i (n)+2μ i e i (n)x i ′(n), where μ i To adjust the step size;

[0069] Where μ i This is the correction step size for the notch filter controller parameters.

[0070] Figure 2 The figure shows a comparison between the adaptive double notch control and the traditional harmonic control under three-frequency steady-state harmonic excitation. It can be seen that the adaptive double notch algorithm reduces the response by 89% within the first 3 seconds of control and by 99% after stabilization. The traditional notch algorithm reduces the response by 73% within the first 3 seconds of control and by 95% after stabilization. The results indicate that the adaptive double notch control has better control convergence performance under three-frequency excitation and a faster convergence speed compared to the traditional harmonic control.

[0071] This invention designs a response separator and controller based on a notch filter, and proposes an active control algorithm for multi-frequency vibration of helicopters based on an adaptive dual notch filter. This algorithm can separate the frequencies of each order in the response to be controlled, realize the simultaneous independent control of multiple frequencies, improve the convergence speed of the multi-frequency control system, and reduce the computational load of multi-frequency multi-channel control.

[0072] This embodiment also provides a helicopter adaptive dual notch filter multi-frequency vibration active control device, including a notch filter response separation module and a notch filter control module.

[0073] The notch response separation module is used to achieve notch response separation through reference signal synthesis, notch response separator and adaptive separation algorithm;

[0074] The notch control module is used to implement notch control through reference signal synthesis, a notch controller, and an adaptive control algorithm.

[0075] In its specific implementation, this application provides a computer storage medium and a corresponding data processing unit. The computer storage medium is capable of storing a computer program, which, when executed by the data processing unit, can run the invention's content regarding a helicopter adaptive dual-notch filter multi-frequency vibration active control method, as well as some or all of the steps in various embodiments. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0076] Those skilled in the art will clearly understand that the technical solutions in the embodiments of the present invention can be implemented using computer programs and their corresponding general-purpose hardware platforms. Based on this understanding, the technical solutions in the embodiments of the present invention, or the parts that contribute to the prior art, can be embodied in the form of computer programs, i.e., software products. These computer program software products can be stored in a storage medium and include several instructions to cause a device containing a data processing unit (which may be a personal computer, server, microcontroller, MUU, or network device, etc.) to execute the methods described in various embodiments or certain parts of the embodiments of the present invention.

[0077] This invention provides a method for active control of multi-frequency vibration of a helicopter using an adaptive dual notch filter. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for active control of multi-frequency vibration of a helicopter using an adaptive dual notch filter, characterized in that, Includes the following steps: Step 1: Notch response separation is achieved through reference signal synthesis, notch response separator, and adaptive separation algorithm; Step 2: Notch control is implemented through reference signal synthesis, notch controller, and adaptive control algorithm; Step 1 includes: Step 101: Determine the number of rotor blades N based on the characteristics of the helicopter rotor; Step 102: Obtain the rotor speed signal Ω from the rotor excitation f(n), and obtain the rotor passing frequency NΩ and its higher-order harmonics iNΩ, where i = 1, 2, ..., R, and R is the harmonic order to be controlled; Step 103: Construct the i-th order frequency reference signal x of the notch filter response separator based on the harmonic frequency iNΩ. i (n)=[sin(iNΩn) cos(iNΩn)], x i (n) contains two reference signals, a sine and a cosine, where n is a discrete-time variable; Step 104, Notch Response Separator for Harmonic Frequency iNΩ Includes 2 response separation parameters Corresponding to sine and cosine respectively, they are represented as Assign initial values T denotes matrix transpose; Step 105: Obtain the control error e(n) which includes the superposition of multiple harmonic responses; Step 106, based on the reference signal x i (n), after notch response separator Generate the notch response separation signal for the i-th harmonic frequency Step 107: Calculate the separation error of the control error e(n) after notch response separation. Step 108, notch response separator Iterate over the parameters; Step 2 includes: Step 201: Construct the i-th order frequency reference signal x of the notch filter controller based on the harmonic frequency iNΩ. i (n)=[sin(iNΩn) cos(iNΩn)], x i (n) contains two reference signals, a sine and a cosine, where n is a discrete-time variable; Step 202, control channel estimation H c ′ is a finite impulse response model established based on the control channel, and the control channel estimates H. c The length of ′ is N c The notch control reference signal x at the i-th order frequency i (n) H needs to be estimated through the control channel. c Pre-filtering generates a pre-filtered reference signal. Step 203, notch filter controller w for harmonic frequency iNΩ i (n) contains 2 control parameters w i s (n), w i c (n), corresponding to sine and cosine respectively, denoted as w i (n)=[w i s (n) w i c (n)] T Assign initial value w i (n) = [0 0] T ; Step 204, based on the reference signal x i (n), controlled by the notch filter controller parameter w i (n), the control signal u that generates the i-th harmonic. i (n)=w i (n)x i (n); Step 205: The control signals of each harmonic order are superimposed to form the control signal u(n). Step 206, the rotor excitation f(n) passes through the main channel H p (n) is transmitted to the helicopter body, generating a body vibration response d(n); Step 207, the control signal u(n) passes through the control channel H c This generates a control response y(n) = H c u(n); Step 208: The body vibration response d(n) and the control response y(n) are superimposed to form the control error e(n); Step 209, adjust the notch filter controller parameters w i Iterate over the parameters of (n).

2. The method according to claim 1, characterized in that, In step 107, the control error e(n) is calculated using the following formula, which is the separation error after notch filter response separation.

3. The method according to claim 2, characterized in that, In step 108, the notch response separator The parameter iteration is implemented using the minimum mean square error algorithm, which utilizes the notch response separator parameters from the previous time step. Separation error and reference signal x i (n) Iterates, and the notch response separator at the next time step The parameter formula is: in This is the correction step size for the notch response separator parameters.

4. The method according to claim 3, characterized in that, In step 208, the control error e(n) is calculated using the following formula: e(n) = d(n) - y(n), but 5. The method according to claim 4, characterized in that, In step 209, the notch filter controller parameter w i The parameter iteration of (n) is implemented using the minimum mean square error algorithm, which utilizes the notch filter parameters w(n) and control error from the previous time step. and pre-filtered reference signal x i Iterate through ′(n) to obtain the notch controller parameters w at the next time step. i The formula for the parameter (n+1) is: In i (n+1)=in i (n)+2μ i e i (n)x i ′(n), Where μ i This is the correction step size for the notch filter controller parameters.

6. A helicopter adaptive dual notch filter multi-frequency vibration active control device, used to implement the method as described in any one of claims 1 to 5, characterized in that, Includes a notch response separation module and a notch control module; The notch response separation module is used to achieve notch response separation through reference signal synthesis, notch response separator and adaptive separation algorithm; The notch control module is used to implement notch control through reference signal synthesis, a notch controller, and an adaptive control algorithm.

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