Rotor phase regulation and control method for active vibration control of multi-rotor aircraft

Abstract

The invention provides a rotor phase regulation and control method for active vibration control of a multi-rotor aircraft. The rotor phase regulation and control method is characterized by comprising a multi-rotor phase coordination strategy, an active control method and a rotor phase regulation and control algorithm. Active coordination of multi-rotor phases is realized through independent control of different paired dual-rotor phases and phase differences between the paired two rotors; establishing a control channel model from rotor loads to control points, taking three-way weighted vibration acceleration at the control points as a control target, and adopting an optimal control strategy to optimize multi-rotor phase control parameters; multi-rotor phase optimal regulation and control are realized through a rotating speed planning strategy, so that the vibration level of the multi-rotor aircraft is effectively reduced, and the comfort and reliability of the multi-rotor aircraft are improved.

Description

Technical field:

[0001] The present invention relates to the field of vibration control technology, and in particular to a rotor phase control method for active vibration control of a multi-rotor aircraft. Background technology:

[0002] With the development of multi-rotor aircraft technology, large-load and manned electric multi-rotor aircraft have received more and more attention. The research and development of electric vertical take-off and landing (eVTOL) aircraft faces many challenges. Among them, the fields of multi-rotor aerodynamic interference, aerodynamic noise and handling quality have received more attention and research. However, so far, there has been little research on structural vibration and its control technology that are closely related to comfort and reliability. The anti-vibration needs of airborne equipment are usually achieved by traditional vibration isolation technology.

[0003] As a rotorcraft, the vibration control technology of helicopters has been developed for many years, including active control strategies such as high-order harmonic control, independent blade control, active torsion rotor and active control of structural response, as well as passive control strategies such as hub vibration absorption and main vibration reduction isolation. However, due to the small size of the rotor system of multi-rotor aircraft, the simple control strategy and the additional weight and space requirements of the vibration reduction system, the traditional helicopter vibration control technology is difficult to apply in the vibration control of multi-rotor aircraft. The present invention proposes a multi-rotor aircraft vibration active control method, which takes the three-way weighted vibration acceleration at the point of interest as the control target, controls different rotor phases through multi-rotor active coordination to achieve the optimal control of the vibration level of the multi-rotor aircraft. Summary of the invention:

[0004] The present invention proposes a rotor phase control method for active vibration control of a multi-rotor aircraft, which effectively reduces the vibration level of the multi-rotor aircraft and improves the comfort and reliability of the multi-rotor aircraft.

[0005] 1. The rotor phase control method for active vibration control of a multi-rotor aircraft is characterized by comprising a multi-rotor phase coordination strategy, an active control method and a rotor phase control algorithm;

[0006] 2. The multi-rotor phase coordination strategy is to control the phases of different rotors of the multi-rotor aircraft to change the phase characteristics of the rotor dynamic load;

[0007] 201. The multi-rotor phase coordination strategy is achieved by different phases between paired dual rotors and between paired two rotors.

[0008] Phase difference independent control is achieved;

[0009] 202. The paired double rotors are two rotors that are symmetrically reversed relative to the longitudinal axis of the fuselage;

[0010] 203. The phase difference between the different pairs of dual rotors is independently controlled to be Yk =Y0+DY k , where Y k k

[0011] The first pair of dual rotor control phase, Y0 is the initial value, DY k is the phase difference of the kth pair of dual rotors;

[0013] 204. The phase difference between the two paired rotors is independently controlled to be Y k =Y k ±Df k , where Y k For the kth pair

[0014] The left and right rotor control phase, Df k is the control phase difference of the kth pair of two rotors;

[0015] 3. The active control method includes control system modeling and control algorithm;

[0016] 301. The control system modeling includes the calculation modeling of the dynamic load of the rotor of the multi-rotor aircraft and the rotor to the target

[0017] Modeling of control channels with marked control points;

[0018] 302. In the rotor dynamic load calculation modeling, the structural modeling adopts elastic beams, and the aerodynamic modeling adopts quasi-fixed

[0019] Constant or unsteady aerodynamic model, optional use of moderate deformation beam model, Leishman-Beddoes

[0020] The cross-section aerodynamic model and the Peters-He dynamic inflow model are used to solve the aeroelastic coupling model to obtain the rotor hub dynamic load R(N, Y) = F x F y F z M x M y M z T ×e iNW+Y ,in

[0021] F x ,F y ,F z ,M x ,M y ,M z is the function of motor speed, attitude angle and flight speed, Y is

[0022] Rotor phase;

[0023] 303. The motor speed, attitude angle and flight speed are provided by the control computer;

[0024] 304. The control channel modeling adopts finite element method and model correction technology, and adopts structural finite element modeling.

[0025] The finite element model of the three-dimensional body is constructed, and the finite element model is modified by modal testing technology. The control channel model from the kth rotor to the i-th control point is obtained by frequency response function calculation.

[0026] 305. The control algorithm adopts the frequency domain optimal control algorithm, and the acceleration response of the control target point is

[0027]

[0028] 306. The control target of the control algorithm is Where W is the i-th control point

[0029] Adding a vibration weighting matrix;

[0030] 307. The frequency domain optimal control algorithm is Among them U k =u r +iu i , 4. The rotor phase adjustment is achieved by controlling the motor speed;

[0031] 401. The motor speed control is characterized by controlling the target phase value Y k and angular velocity trajectory planning module;

[0032] 402. The angular velocity trajectory planning module has another feature of taking the angular velocity as a polynomial form with respect to the control time t, and optionally using a fifth-order polynomial ω(t)=a5t 5 +a4t 4 +a3t 3 +a2t 2 +a1t+a0; 403. The angular velocity trajectory planning module is based on the angle boundary conditions ω(0), ω(T), angular acceleration boundary conditions And control target phase Y k With the current phase Difference calculation, where T is the phase control time, and ω(0)=ω(T)=ω c , At the same time, the power minimization requirement of the control process is met; 404. The motor speed control is implemented by the speed controller in the flight control.

[0033] Beneficial effects:

[0034] The present invention performs active vibration control of a multi-rotor aircraft by optimizing and regulating the multi-rotor pairing phase, achieving a better control effect than active vibration control without optimizing and regulating the multi-rotor pairing phase. Figure 3 As shown in the figure, after the active vibration control of the multi-rotor pairing phase optimization regulation is carried out, the acceleration response amplitudes in three directions at the center of gravity of the aircraft are significantly reduced, and a significant vibration control effect is achieved. Description of the drawings:

[0035] Figure 1 Schematic diagram of active vibration control method for multi-rotor aircraft;

[0036] Figure 2 Schematic diagram of multi-rotor pairing phase control strategy.

[0037] Figure 3 Comparison of the acceleration response amplitudes in three directions at the center of gravity of the aircraft with and without active vibration control for multi-rotor pairing phase optimization control Specific implementation method:

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The illustrated embodiment is only one implementation of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The present invention proposes a rotor phase control method for active vibration control of a multi-rotor aircraft. In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings, taking a six-rotor as an example and its specific implementation method. Figure 1 , Figure 2 1. The multi-rotor aircraft vibration active control method is characterized by including a multi-rotor phase coordination strategy, an active control method and a rotor phase control algorithm;

[0040] 2. The multi-rotor phase coordination strategy is to control the phases of different rotors of the multi-rotor aircraft to improve

[0041] Phase characteristics of variable rotor wing dynamic loads;

[0042] 201. The multi-rotor phase coordination strategy is achieved by using the phase difference DY between different paired dual rotors (1-2), (3-4) and (5-6) 1-2 , DY 3-4 , DY 4-5 The phase difference Df between the two paired rotors 1-2, 3-4, 5-6 1-2 , Df 3-4 , Df5-6 Independent control implementation;

[0043] 202. The paired double rotors are two rotors that are symmetrically reversed relative to the longitudinal axis of the fuselage. Figure 2 Middle 1-2, 3-4, 5-6;

[0045] 203. The phase difference between the different pairs of dual rotors is independently controlled as Y1=Y2=Y0+DY 1-2 ,

[0046] Y3=Y4=Y0+DY 3-4 , Y1=Y2=Y0+DY 5-6 , Y0 is the initial value, which can be selected as 0; 204. The phase difference between the two paired rotors is independently controlled as Y1=Y1+Df 1-2 , Y2=Y2-Df 1-2 ,

[0047] Y3=Y3+Df 3-4 , Y4=Y4-Df 3-4 , Y5=Y5+Df 5-6 , Y6=Y6-Df 5-6 ; 3. The active control method includes control system modeling and control algorithm;

[0048] 301. The control system modeling includes the calculation modeling of the dynamic load of the rotor of the multi-rotor aircraft and the rotor to the target

[0049] Modeling of control channels with marked control points;

[0050] 302. In the rotor dynamic load calculation modeling, the structural modeling adopts elastic beams, and the aerodynamic modeling adopts quasi-fixed

[0051] Constant or unsteady aerodynamic model, optional use of moderate deformation beam model, Leishman-Beddoes

[0052] The cross-section aerodynamic model and the Peters-He dynamic inflow model are used to solve the aeroelastic coupling model to obtain the rotor hub dynamic load R(N, Y) = F x F y F z M x M y M z T ×e iNW+Y ,in

[0053] F x ,F y ,F z ,M x ,M y ,Mz is the function of motor speed, attitude angle and flight speed, Y is

[0054] The fourth phase;

[0055] 303. The control channel modeling adopts finite element method and model correction technology, and structural finite element modeling

[0056] The finite element model of the three-dimensional body is constructed, and the finite element model is modified by modal testing technology. The control channel model from the kth rotor to the i-th control point is obtained by frequency response function calculation.

[0057] 304. The control algorithm adopts the frequency domain optimal control algorithm, and the control target point response is

[0058]

[0059] 305. The control target of the control algorithm is Where W is the i-th control point

[0060] Adding a vibration weighting matrix;

[0061] 306. The frequency domain optimal control algorithm is Among them U k =u r +iu i , 4. The rotor phase adjustment is achieved by controlling the motor speed;

[0062] 401. The motor speed control is characterized by controlling the target phase value Y k and angular velocity trajectory planning module;

[0063] 402. The angular velocity trajectory planning module has another feature of taking the angular velocity as a polynomial form with respect to the control time t, and optionally using a fifth-order polynomial ω(t)=a5t 5 +a4t 4 +a3t 3 +a2t 2 +a1t+a0; 403. The angular velocity trajectory planning module is based on the angle boundary conditions ω(0), ω(T), angular acceleration boundary conditions And control target phase Y k With the current phase Difference calculation, where T is the phase control time, and ω(0)=ω(T)=ω c , At the same time, the power minimization requirement of the control process is met; 404. The motor speed control is implemented by the speed controller in the flight control.

Claims

1. A rotor phase control method for active vibration control of a multi-rotor aircraft, characterized in that It includes multi-rotor phase coordination strategy, active control method and rotor phase control algorithm.

2. According to claim 1, the multi-rotor phase coordination strategy is to control the phases of different rotors of the multi-rotor aircraft to change the phase characteristics of the rotor dynamic load.

3. According to claim 1, the multi-rotor phase coordination strategy is implemented by independently controlling the phase between different paired dual rotors and the phase difference between the paired two rotors.

4. According to claim 3, the paired twin rotors are two rotors that are symmetrically reversed relative to the longitudinal axis of the fuselage.

5. According to claim 3, the phases between different pairs of dual rotors are independently controlled as Y k =Y0+DY k , where Y k is the kth pair of dual rotor control phase, Y0 is the initial value, DY k is the control phase of the kth pair of dual rotors.

6. According to claim 3, the phase difference between the two paired rotors is independently controlled to be Y k =Y k ±Df k , where Y k is the control phase of the kth pair of left and right rotors, Df k is the control phase difference between the kth pair of rotors.

7. The active control method according to claim 1 comprises control system modeling and control algorithm.

8. According to claim 7, the control system modeling includes the calculation modeling of the dynamic load of the rotor of the multi-rotor aircraft and the modeling of the control channel from the rotor to the target control point.

9. In the rotor dynamic load calculation modeling according to claim 8, the structural modeling adopts an elastic beam, the aerodynamic model adopts a quasi-steady or unsteady aerodynamic model, and the medium deformation beam model, the Leishman-Beddoes section aerodynamic model and the Peters-He dynamic inflow model are optionally adopted to solve the aeroelastic coupling model to obtain the rotor hub dynamic load R(N, Y) = F x F y F z M x M y M z T × e iNW+Y , where F x ,F y ,F z ,M x ,M y ,M z is a function of motor speed, attitude angle, and flight speed, and Y is the initial rotor phase.

10. According to claim 8, the control channel modeling adopts the finite element method and model correction technology, the body finite element model is established by structural finite element, and the finite element model is corrected by modal testing technology, and the control channel model from the kth rotor to the ith control point is obtained by frequency response function calculation 11. According to claim 7, the control algorithm adopts the frequency domain optimal control algorithm, and the acceleration response of the control target point is 12. The control target of the control algorithm according to claim 7 is Where W is the three-way vibration weighted matrix of the i-th control point.

13. According to claim 11, the frequency domain optimal control algorithm is Among them U k =u r +iu i , 14. According to claim 1, the rotor phase adjustment is achieved by controlling the motor speed.

15. The motor speed control according to claim 14, characterized in that the control target phase value Y k And angular velocity trajectory planning module.

16. The angular velocity trajectory planning module according to claim 15, wherein the angular velocity is expressed as a polynomial with respect to the control time t, and a fifth-order polynomial is optionally used.

17. The angular velocity trajectory planning module according to claim 15 is configured by using angle boundary conditions ω(0), ω(T), angular acceleration boundary conditions And control target phase Y k With the current phase Difference calculation, where T is the phase control time, and ω(0)=ω(T)=ω c , At the same time, it meets the power minimization requirements of the control process.

18. According to claim 15, the motor speed control is achieved by a speed controller in flight control.

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