A time domain servo compensation control method for driver multiple frequency sinusoidal signal

Abstract

The application discloses a time domain servo compensation control method for a driver multiple frequency sinusoidal signal, which is composed of 2n+1 parallel error compensation control loops, wherein n is the number of harmonic frequencies contained in an expected signal; the error compensation control loop is divided into two types: one type of loop is a steady-state error compensation loop, and a point-by-point error compensation control method is adopted to realize error compensation of 0 / rev frequency; the other type of loop is a high-frequency harmonic signal error compensation control loop, which is used for respectively compensating and controlling positive and cosine components of high-frequency harmonic signals. The application solves the problems of actuator response lag and motion incoordination caused by inconsistent blades of a driving device such as a "piezoelectric driver-trailing edge flap device" in the application of helicopter vibration active control.

Description

Technical Field

[0001] This invention belongs to the field of active vibration control technology for helicopters, and relates to a time-domain servo compensation control method for multi-frequency sinusoidal signals of a driver. Background Technology

[0002] Vibration and noise have always been thorny issues in helicopter development and operation. As modern helicopters achieve increasingly higher performance specifications and their mission environments become more complex and variable, the inherent limitations of passive vibration suppression technologies—such as narrow bandwidth, poor low-frequency characteristics, and high structural weight—become more prominent. Active vibration control technology for helicopters, developed only in the last decade or so, has attracted widespread attention due to its unparalleled advantages over passive vibration suppression. Among active vibration control technologies for helicopters, the most attention-grabbing are the Active Structural Response Control (ACSR) system and the Active Controlled Rotor (ACF) system. The ACSR system is primarily used for active control of the airframe's structural response and has significant application prospects. The ACF system acts on the main source of helicopter vibration—the rotor—such as... Figure 6 As shown, European and American countries have already completed flight demonstration and verification tests of the ACF rotor.

[0003] ACF rotor control systems typically consist of a mission layer (vibration reduction, noise reduction, online cone balancing, etc.) and a drive servo control layer. For a four-bladed ACF rotor, vibration reduction requires the trailing edge flaps to be excitation signals of sinusoidal signals with different amplitudes and phases of 3, 4, and 5 / rev. Noise suppression usually uses 2 / rev excitation, while online cone balancing requires 0 and 1 / rev excitation. Therefore, a four-bladed ACF rotor may need to control the movement of the trailing edge flaps at frequencies of 0-5 / rev.

[0004] Currently, most ACF rotor systems employ piezoelectric actuators for trailing edge flap actuation. Due to the hysteresis effect of piezoelectric materials, the phase lag and amplitude attenuation of the actuator feedback signal increase with higher excitation frequencies. Furthermore, errors in the assembly and manufacturing of ACF actuators for different blades result in variations between the actuators of each blade. Therefore, servo control must be applied to the trailing edge flaps of each blade to ensure coordinated movement of the trailing edge flaps across the blades.

[0005] The control signal for the trailing edge flap actuator can be represented by a series of harmonics:

[0006]

[0007] In the above formula, Ω represents the rotor angular velocity, and u offset This represents the bias voltage, and n represents the n / rev harmonic.

[0008] Boeing used a continuous time-domain high-order harmonic control algorithm (CTHHC) for drive control in its "SMART ROTOR" project, such as... Figure 7 As shown, the CTHHC controller is similar to a classic sinusoidal disturbance suppression compensator, especially in the open-loop response, where the integral action makes the gain at frequency N / rev infinite, thus completely suppressing the N / rev frequency. The CTHHC control method is based on the linear quasi-static assumption, using a T matrix to represent the relationship between the driver control input and output response at each frequency. The T matrix can be obtained through open-loop identification. For the 0th-order steady-state signal, an integral controller is used. (Reference: Active Flap Control of the SMART Rotor for Vibration Reduction, 65) th (AHS, 2009)

[0009] The China Helicopter Design Institute proposed a driver hysteresis compensation control method with a two-level cascaded control system in the time domain and frequency domain in patent application number 201911232639.1, such as... Figure 8 As shown, its inner layer is time-domain point-by-point error compensation control, and the outer layer is frequency-domain error compensation control. After frequency-domain compensation, the control signal is converted into a time-domain signal. Its characteristic is that the outer-layer frequency-domain control requires the acquisition of a full-cycle feedback signal of duration T for spectrum analysis.

[0010] The time-domain CTHHC algorithm requires experimental identification of the transfer matrix of the driver at various excitation frequencies. For a single blade, controlling the 0-5 / rev signal requires identifying 11 parameters; therefore, four blades require a total of 44 parameters. The hysteresis compensation method in patent application number 201911232639.1 requires acquiring a signal for a certain duration for FFT analysis. For 0-5 / rev signal control, FFT generally requires at least one revolution of signal, meaning its outer control loop update cycle is one rotor rotation. Therefore, its convergence speed is slow, and it can only meet the needs of frequency-domain vibration reduction control tasks similar to HHC, but cannot meet the requirements of point-by-point continuous control of time-domain vibration reduction control laws such as time-domain CTHHC. Summary of the Invention

[0011] Objective: To provide a time-domain servo compensation control method for multi-frequency sinusoidal signals of actuators. This invention solves the problems of actuator response lag and motion incoordination caused by inconsistencies between blades in drive devices such as the "piezoelectric actuator-trailing edge flap device" in active vibration control applications of helicopters.

[0012] Technical Solution: A time-domain servo compensation control method for driving multi-frequency sinusoidal signals, consisting of 2n+1 parallel error compensation control loops, where n is the number of harmonic frequencies contained in the desired signal; the error compensation control loops are divided into two categories: one type is a steady-state error compensation loop, which uses a point-by-point error compensation control method to achieve error compensation at the 0 / rev frequency; the other type is a high-frequency harmonic signal error compensation control loop, used to compensate and control the sine and cosine components of the high-frequency harmonic signal respectively.

[0013] In the aforementioned time-domain servo compensation control method for multi-frequency sinusoidal signals of a driver, the steady-state error compensation loop includes one loop.

[0014] In the aforementioned time-domain servo compensation control method for multi-frequency sinusoidal signals of a driver, the point-by-point error compensation control is PID control.

[0015] In the aforementioned time-domain servo compensation control method for driving multi-frequency sinusoidal signals, the high-frequency harmonic signal error compensation control loop includes 2n loops.

[0016] In the aforementioned time-domain servo compensation control method for driving multi-frequency sinusoidal signals, the compensation control of the high-frequency harmonic signal error compensation control loop is as follows: the sine and cosine components of the multi-frequency harmonic signal are demodulated by a combination of signal modulation +1 / rev notch and low-pass filter, and then compensation is performed by a point-by-point error compensation control method.

[0017] In the aforementioned time-domain servo compensation control method for driving multi-frequency sinusoidal signals, the demodulation process is as follows:

[0018] Demodulate the feedback signal Z(t), and multiply the feedback signal Z(t) by 2cos4Ωt and 2sin4Ωt respectively to obtain:

[0019]

[0020]

[0021] Where A0~A5 are the amplitudes of the cosine signals of each order in the Z(t) signal, Ω is the fundamental frequency of the rotor speed in radians per second, and ω1t~ω5t represent the phase angles of the cosine signals of each order as a function of time.

[0022] Demodulated signal and By combining a 1 / rev notch filter and a low-pass filter, frequency components at 1 / rev and above are eliminated, resulting in:

[0023] A 4c =A4cos(ω4t)

[0024] A 4s =A4sin(ω4t);

[0025] That is, the 4 / rev frequency harmonic component of the source signal Z(t):

[0026] Z 4P (t)=A4cos(4Ωt-ω4t)

[0027] =A4cos(ω4t)cos(4Ωt)+A4sin(ω4t)sin(4Ωt)

[0028] =A 4c cos(4Ωt)+A 4s sin(4Ωt).

[0029] In the aforementioned time-domain servo compensation control method for a multi-frequency sinusoidal signal of a driver, the feedback signal Z(t) is:

[0030] Z(t)=A0+A1cos(1Ωt-ω1t)+A2cos(2Ωt-ω2t)+

[0031] A3cos(3Ωt-ω3t)+A4cos(4Ωt-ω4t)+A5cos(5Ωt-ω5t)

[0032] In the aforementioned time-domain servo compensation control method for multi-frequency sinusoidal signals of the driver, the correspondence between the frequency components in the feedback signal Z(t) and the frequency components in the 1-5 / rev demodulated signal is shown in the table below:

[0033]

[0034] Beneficial Effects: This invention proposes a time-domain servo compensation control method for a driver based on time-domain demodulation of multi-harmonic sinusoidal signals. This method avoids the problem of CTHHC method requiring prior experimental identification of a series of transfer function parameters; it also solves the problem in patent application number 201911232639.1 that the outer frequency domain control of the hysteresis compensation controller has a slow update speed and is not suitable for point-by-point control of mission layers such as time-domain vibration reduction control laws in ACF rotors. The control effect is shown in [see details]. Figure 3 .

[0035] This invention modulates a multi-harmonic sinusoidal signal Z(t). Taking the fourth-order modulation frequency as an example, the modulated signal... The signal will contain frequency components of various orders, among which the useful information is at ω4 where the frequency is much smaller than Ω. Compared with the scheme with only a "low-pass filter", the "1 / rev notch filter + low-pass filter" proposed in this invention can effectively improve the signal suppression capability at 1 / rev. Figure 4The Bode plot of the 1 / rev notch filter + low-pass filter is shown in the image. The filtering effect is as follows: Figure 5 As shown, the cosine component extracted by the "1 / rev notch filter + low-pass filter" is smooth and clean, while the cosine component extracted by the "low-pass filter" scheme still contains a certain 1 / rev frequency component. Furthermore, the lower the cutoff frequency of the low-pass filter, the greater the phase lag of the extracted sine and cosine components, and the longer the convergence time of the closed-loop system. Therefore, the combined filtering scheme of "1 / rev notch filter + low-pass filter" can also improve the convergence speed of the closed-loop control system.

[0036] This invention proposes a time-domain servo compensation control method for a driver's multi-frequency sinusoidal signal, which consists of 2n+1 parallel error compensation control loops, such as... Figure 1 As shown, it can compensate point-by-point for the steady-state value of multi-harmonic signals and the sine and cosine components (or the amplitude and phase of harmonics) of each frequency. In the uncontrolled state, the relationship between the output displacement response corresponding to a typical multi-harmonic sinusoidal excitation voltage of a piezoelectric actuator is as follows: Figure 2 The expected signal and feedback signal are shown in the figure. The control effect after adopting the closed-loop control method proposed in this invention is as follows: Figure 3 As shown, the feedback signal rapidly approaches the desired signal point by point. According to the error compensation controller parameters in the current simulation, the feedback signal basically overlaps with the desired signal after about 6 rotor rotation cycles. If the controller parameters are further adjusted, the convergence period can be further shortened. Attached Figure Description

[0037] Figure 1 This is a structural diagram of a time-domain servo compensation controller module for a driver based on a multi-frequency harmonic signal demodulation method using a combination of signal modulation +1 / rev notch filtering and low-pass filter.

[0038] Figure 2 This is a schematic diagram showing the time-domain comparison between the expected signal (0-5 / rev) and the actuator feedback signal under uncontrolled conditions.

[0039] Figure 3 A schematic diagram showing the time-domain comparison of the closed-loop control response of the 0-5 / rev expected signal for the actuator using the time-domain compensation control method described in this invention.

[0040] Figure 4 This is a Bode plot of a combination of a 1 / rev notch filter and a low-pass filter.

[0041] Figure 5 A comparison of the effects of a combination of 1 / rev notch filters and 0.5 / rev low-pass filters versus a single 0.5 / rev low-pass filter.

[0042] Figure 6 This is a schematic diagram of the trailing edge flap blade section of the ACF rotor.

[0043] Figure 7 This is a schematic diagram of the continuous-time high-order harmonic control (CTHHC) algorithm.

[0044] Figure 8 The method for driver hysteresis compensation control is described in patent application number 201911232639.1. Detailed Implementation

[0045] Example 1. A time-domain servo compensation control method for a driver's multi-frequency sinusoidal signal, participating in... Figures 1-8 Its purpose is to solve the problems of actuator response always lagging behind the desired signal and the control coordination between drivers. The time-domain control algorithm for this driver consists of multiple parallel error compensation control loops, such as... Figure 1 As shown. Parallel circuits are mainly divided into two categories. One type is the steady-state error compensation circuit, which generally requires only one circuit. It uses point-by-point error compensation control (such as PID control) to achieve error compensation for the 0 / rev frequency, i.e., the steady-state signal. The other type is the high-frequency harmonic signal error compensation control circuit, which generally contains 2n circuits (n is the number of harmonic frequencies contained in the desired signal), and performs compensation control on the sine and cosine components of the high-frequency harmonic signal respectively.

[0046] For a four-bladed ACF rotor system, the excitation frequency of its trailing edge flap actuator is typically between 0 and 5 rev, depending on mission requirements such as vibration reduction and noise reduction. Therefore, the feedback signal Z(t) of the ACF rotor trailing edge flap actuator, which generally includes aperiodic components, is:

[0047] Z(t)=A0+A1cos(1Ωt-ω1t)+A2cos(2Ωt-ω2t)+

[0048] A3cos(3Ωt-ω3t)+A4cos(4Ωt-ω4t)+A5cos(5Ωt-ω5t)

[0049] Where A represents the amplitude of the cosine signal at each frequency, Ω represents the rotor speed in radians per second, and ωt represents the slow time-varying phase angle of the cosine signal at each frequency. To track the continuously changing sine and cosine components of the desired signal for the outer task, such as the vibration reduction CTHHC control law, the sine and cosine components of the driver's harmonic excitation response must also change continuously with time. Note: This invention requires that the convergence period of the outer control be greater than the rotor rotation period T corresponding to the 1 / rev frequency, i.e., ω < Ω, so that the demodulation method formed by the 1 / rev notch filter + low-pass filter combination can extract the harmonic components in a timely and accurate manner.

[0050] The key point of this invention is the demodulation process of multi-harmonic signals based on a combination of signal modulation +1 / rev notch filtering and low-pass filter, as follows:

[0051] Taking the extraction of the 4 / rev frequency as an example, the feedback signal Z(t) is demodulated, and the feedback signal Z(t) is multiplied by 2cos4Ωt and 2sin4Ωt respectively to obtain:

[0052]

[0053]

[0054] The correspondence between the frequency components in the feedback signal Z(t) and the frequency components in the 1-5 / rev demodulated signal is shown in the table below.

[0055]

[0056] As can be seen from the table above, the demodulated signal generally contains harmonic components of 1-5 / rev and higher frequencies, while the sine and cosine components of the N / rev harmonic to be extracted are contained in the 0 / rev signal components.

[0057] Therefore, the demodulated signal and By combining a 1 / rev notch filter and a low-pass filter, frequency components at 1 / rev and above are eliminated, resulting in:

[0058] A 4c =A4cos(ω4t)

[0059] A 4s =A4sin(ω4t)

[0060] That is, the 4 / rev frequency harmonic component of the source signal Z(t):

[0061] Z 4P (t)=A4cos(4Ωt-ω4t)

[0062] =A4cos(ω4t)cos(4Ωt)+A4sin(ω4t)sin(4Ωt)

[0063] =A 4c cos(4Ωt)+A 4s sin(4Ωt)

[0064] The purpose of using a 1 / rev notch filter combined with a low-pass filter here is to balance the convergence speed of the low-pass filter with the cancellation effect of signals at frequencies of 1 / rev and above. The lower the cutoff frequency of the low-pass filter, the slower the convergence speed and the greater the phase lag of the filtered signal. Figure 4 As can be seen from the BODE diagram of the combination of 1 / rev notch and low-pass filter, the 1 / rev notch filter can effectively enhance the filtering effect of the signal at the 1 / rev frequency.

[0065] Example 2. A time-domain servo compensation control method for driving multi-frequency sinusoidal signals, consisting of 2n+1 parallel error compensation control loops, where n is the number of harmonic frequencies contained in the desired signal; the error compensation control loops are divided into two types: one type is a steady-state error compensation loop, which uses a point-by-point error compensation control method to achieve error compensation for the 0 / rev frequency (steady-state signal); the other type is a high-frequency harmonic signal error compensation control loop, used to compensate and control the sine and cosine components of the high-frequency harmonic signal respectively.

[0066] The steady-state error compensation loop consists of one loop.

[0067] The aforementioned point-by-point error compensation control is PID control.

[0068] The aforementioned high-frequency harmonic signal error compensation control loop contains 2n loops.

[0069] The aforementioned high-frequency harmonic signal error compensation control loop performs the following compensation control: the sine and cosine components of the multi-harmonic signal are demodulated by a combination of signal modulation +1 / rev notch and low-pass filter (this method can efficiently extract the sine and cosine harmonic components of each order frequency in the multi-harmonic signal point by point), and then compensation is performed by a point-by-point error compensation control method.

[0070] The aforementioned demodulation process is as follows:

[0071] Demodulate the feedback signal Z(t), and multiply the feedback signal Z(t) by 2cos4Ωt and 2sin4Ωt respectively to obtain:

[0072]

[0073]

[0074] Where A0~A5 are the amplitudes of the cosine signals of each order in the Z(t) signal, Ω is the fundamental frequency of the rotor speed in radians per second, and ω1t~ω5t represent the phase angles of the cosine signals of each order as a function of time.

[0075] Demodulated signal and By combining a 1 / rev notch filter and a low-pass filter, frequency components at 1 / rev and above are eliminated, resulting in:

[0076] A 4c =A4cos(ω4t)

[0077] A 4s =A4sin(ω4t);

[0078] That is, the 4 / rev frequency harmonic component of the source signal Z(t):

[0079] Z 4P (t)=A4cos(4Ωt-ω4t)

[0080] =A4cos(ω4t)cos(4Ωt)+A4sin(ω4t)sin(4Ωt)

[0081] =A 4c cos(4Ωt)+A 4s sin(4Ωt).

[0082] The feedback signal Z(t) is:

[0083] Z(t)=A0+A1cos(1Ωt-ω1t)+A2cos(2Ωt-ω2t)+

[0084] A3cos(3Ωt-ω3t)+A4cos(4Ωt-ω4t)+A5cos(5Ωt-ω5t)

[0085] The correspondence between the frequency components of the feedback signal Z(t) and the frequency components of the 1-5 / rev demodulated signal is shown in the table below:

[0086]

Claims

1. A time-domain servo compensation control method for a driver's multi-frequency sinusoidal signal, characterized in that... It consists of 2n+1 parallel error compensation control loops, where n is the number of harmonic frequencies contained in the desired signal; the error compensation control loops are divided into two categories: one type is a steady-state error compensation loop, which uses a point-by-point error compensation control method to achieve error compensation at the 0 / rev frequency; the other type is a high-frequency harmonic signal error compensation control loop, which is used to compensate and control the sine and cosine components of the high-frequency harmonic signal respectively. The compensation control of the high-frequency harmonic signal error compensation control loop is as follows: the sine and cosine components of the multiple harmonic signals are demodulated by a combination of signal modulation +1 / rev notch and low-pass filter, and then compensation is performed by a point-by-point error compensation control method. The demodulation process is as follows: Demodulate the feedback signal Z(t), and multiply the feedback signal Z(t) by 2cos4Ωt and 2sin4Ωt respectively to obtain: ， ， Where A0~A5 are the amplitudes of the cosine signals of each order in the Z(t) signal, Ω is the fundamental frequency of the rotor speed in radians per second, and ω1t~ω5t represent the phase angles of the cosine signals of each order as a function of time. Demodulated signal and By combining a 1 / rev notch filter and a low-pass filter, frequency components at 1 / rev and above are eliminated, resulting in: A 4c = A4 cos(ω4t) A 4s = A4sin(ω4t); That is, the 4 / rev frequency harmonic component of the source signal Z(t): Z 4P (t)=A4cos(4Ωt-ω4t) =A4cos(ω4t)cos(4Ωt)+A4sin(ω4t)sin(4Ωt) =A 4c cos(4Ωt)+A 4s sin(4Ωt); The correspondence between the frequency components of the feedback signal Z(t) and the frequency components of the 1-5 / rev demodulated signal is shown in the table below: 。 2. The time-domain servo compensation control method for a driver's multi-frequency sinusoidal signal according to claim 1, characterized in that... The steady-state error compensation circuit consists of one loop.

3. The time-domain servo compensation control method for a driver's multi-frequency sinusoidal signal according to claim 1, characterized in that... The point-by-point error compensation control mentioned above is PID control.

4. The time-domain servo compensation control method for a driver's multi-frequency sinusoidal signal according to claim 1, characterized in that... The high-frequency harmonic signal error compensation control circuit comprises 2n circuits.

5. The time-domain servo compensation control method for a driver's multi-frequency sinusoidal signal according to claim 1, characterized in that... The feedback signal Z(t) is: Z(t)=A0+A1cos(1Ωt-ω1t)+A2cos(2Ωt-ω2t)+ A3cos(3Ωt-ω3t)+A4cos(4Ωt-ω4t)+A5cos(5Ωt-ω5t).

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