Helicopter rotor attitude and vibration control method and system

Abstract

The invention relates to a helicopter rotor attitude and vibration control method and system. The control method comprises the following steps that displacement signals of a helicopter rotor hub, vibration signals of the hub and roots of blades and rotating speed signals of a rotor are collected in real time; the real-time value of the attitude angle of the rotor wing is calculated according to the displacement signal of the rotor wing propeller hub, and then the attitude angle error between the real-time value and the target value is calculated; and calculating a PID control quantity based on the attitude angle error and the vibration amplitude of the rotor, and further generating a control instruction to drive a steering engine to control the helicopter rotor to operate according to the target attitude and reduce the noise level of the rotor at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of helicopter rotor control, and in particular to a method and system for controlling the attitude and vibration of a helicopter rotor. Background Art

[0002] A helicopter is an aircraft whose lift and propulsion are generated by its rotor system. Failures during helicopter operation primarily arise from the rotor system, which consists of two components: the blades and the hub. During high-speed rotation, the blades are subject to multiple forces, including lift, air resistance, and the weight of the aircraft, causing them to flap, shimmy, and twist. These movements create complex deformations in the blades, which, over time, can lead to blade wear. Furthermore, the changing attitude of the helicopter rotor exacerbates the helicopter's vibration and noise problems. Therefore, a control method is needed that can generate effective control signals based on the helicopter rotor's attitude and vibration to adjust the rotor's attitude in real time while reducing the helicopter's vibration level. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a helicopter rotor attitude and vibration control method and system, which can adjust the rotor attitude in real time to control the stable flight of the helicopter body and reduce the vibration level of the helicopter.

[0004] The present invention solves the technical problem by adopting a technical solution: providing a method for controlling the attitude and vibration of a helicopter rotor, comprising the following steps:

[0005] Real-time acquisition of helicopter rotor hub displacement signals, hub and blade root vibration signals, and rotor speed signals;

[0006] The real-time value of the rotor attitude angle is calculated based on the displacement signal of the rotor hub, and the attitude angle error between the real-time value and the target value is calculated;

[0007] The PID control variable is calculated based on the attitude angle error and the vibration amplitude of the rotor, and then a control instruction is generated to drive the servo to control the helicopter rotor to operate according to the target attitude while reducing the rotor noise level.

[0008] Furthermore, the PID control quantity is expressed as

[0009]

[0010] Among them, y(t) is the PID control quantity, e(t) is the attitude angle error, k p , k i and k d is the adjustment parameter, k V is the vibration compensation coefficient, A V is the vibration amplitude.

[0011] Furthermore, the displacement signal of the rotor hub is collected by six displacement sensors deployed on the outer flange of the helicopter rotor hub and three displacement sensors deployed on the central platform of the helicopter rotor hub.

[0012] Furthermore, the rotor attitude angle includes the roll angle, pitch angle and heading angle, which are calculated by the following formulas:

[0013]

[0014] Δd i =d i -z0

[0015]

[0016] Among them, θ, φ and are pitch angle, roll angle and heading angle respectively, x i and y i are the coordinates of displacement sensor i on the XY plane, z0 is the overall vertical displacement of the hub, d i is the displacement of displacement sensor i, Δd i is the displacement of displacement sensor i relative to the hub, h i and α i are the radial displacement and central angle of the displacement sensor deployed on the outer flange of the helicopter rotor hub.

[0017] Furthermore, the real-time value of the rotor attitude angle is obtained by weighted averaging the roll angle, pitch angle and heading angle calculated in real time.

[0018] Furthermore, the vibration amplitude of the rotor is obtained by respectively calculating the vibration amplitudes of the hub and the blade root based on the vibration signals of the hub and the blade root, and then performing weighted averaging or taking the maximum value thereof.

[0019] The present invention also provides a helicopter rotor attitude and vibration control system, comprising:

[0020] The first sensor unit is used to collect the displacement signal of the helicopter rotor hub;

[0021] The second sensor unit is used to collect vibration signals of the helicopter rotor hub and blade roots;

[0022] The third sensor unit is used to collect the rotation speed signal of the helicopter rotor;

[0023] A signal processing unit is used to calculate the real-time value of the rotor attitude angle based on the displacement signal of the rotor hub, and then calculate the attitude angle error between the real-time value and the target value; and is also used to calculate the vibration amplitude of the rotor based on the vibration signals of the rotor hub and the blade root;

[0024] A control unit, configured to calculate a PID control variable based on the attitude angle error and the vibration amplitude, and then generate a control instruction;

[0025] The servo is used to control the helicopter rotor to operate according to the target attitude according to the control instructions while reducing the rotor noise level.

[0026] Furthermore, the first sensor unit includes 9 displacement sensors, 6 of which are deployed on the outer flange of the helicopter rotor hub, and 3 of which are deployed on the central platform of the helicopter rotor hub.

[0027] Furthermore, the displacement sensors deployed on the hub outer flange and the helicopter rotor hub central platform are distributed at equal intervals on the first circumference and the second circumference, and the first circumference and the second circumference both have the rotor main shaft center as the circle center.

[0028] Beneficial effects

[0029] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages and positive effects compared with the prior art: the present invention realizes real-time measurement and monitoring of the helicopter rotor attitude angles (roll angle, pitch angle and heading angle) through the dual-circle spatial arrangement of displacement sensors, and combines acceleration sensors and encoders to measure the rotor speed and vibration level in real time. After comprehensive judgment, the rotor attitude is dynamically adjusted through the PID closed-loop feedback dynamic adjustment algorithm to ensure that the helicopter operates smoothly while reducing the vibration level. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flow chart of a first embodiment of the present invention;

[0031] Figure 2 Schematic diagram of the deployment of displacement sensors according to the first and second embodiments of the present invention;

[0032] Figure 3 Schematic diagram of the system structure of the first and second embodiments of the present invention;

[0033] Figure 4 Schematic diagram of the rotor attitude control algorithm of the first and second embodiments of the present invention;

[0034] Figure 5 This is a diagram of the system display interface of the second embodiment of the present invention. DETAILED DESCRIPTION

[0035] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0036] The first embodiment of the present invention relates to a method for controlling the attitude and vibration of a helicopter rotor, such as Figure 1 As shown, the following steps are included:

[0037] Real-time acquisition of helicopter rotor hub displacement signals, hub and blade root vibration signals, and rotor speed signals;

[0038] The real-time value of the rotor attitude angle is calculated based on the displacement signal of the rotor hub, and the attitude angle error between the real-time value and the target value is calculated;

[0039] The PID control variable is calculated based on the attitude angle error and the vibration amplitude of the rotor, and then a control instruction is generated to drive the servo to control the helicopter rotor to operate according to the target attitude while reducing the rotor noise level.

[0040] More specifically, the PID control quantity can be expressed as

[0041]

[0042] Among them, y(t) is the PID control quantity, e(t) is the attitude angle error, k p , k i and k d is the adjustment parameter, k V is the vibration compensation coefficient, A V is the vibration amplitude. After vibration signal acquisition and attitude angle calculation, the error is calculated compared to the target value. The flight control system controls the servo to issue compensation instructions, which in turn controls the rotor motor to control the speed difference and output compensation torque. The vibration level, speed, and attitude angle are continuously monitored in real time. Once the target value is reached, the current value is saved.

[0043] The rotor attitude angle can be measured by existing methods. In some preferred embodiments, the helicopter rotor attitude angle measurement system is composed of 9 linear displacement sensors installed on the rotor hub, and high-precision measurement of roll angle, pitch angle and heading angle is achieved through multi-degree-of-freedom redundant measurement and motion decoupling algorithm. The 9 displacement sensors are spatially redundantly installed on two concentric circles, with 6 displacement sensors distributed on the outer circle, installed at intervals of 60°, and 3 displacement sensors distributed on the inner circle, installed at intervals of 120°; the outer circle measures the radial (roll angle), axial (pitch angle) and tangential (heading angle) of the rotor attitude, and the inner circle is less sensitive to the heading angle, mainly to enhance the robustness of the roll / pitch angle solution. The roll angle, pitch angle and heading angle are weighted averaged to obtain the real-time value of the attitude angle, which is then compared with the target value to obtain the real-time attitude angle error e(t).

[0044] More specifically, the 9 displacement sensors are installed as follows Figure 2 As shown in Figure 1, the 6 displacement sensors of the outer ring (radius R) are installed on the outer flange of the hub, and the 3 displacement sensors of the inner ring (radius r) are installed on the central platform of the hub. The displacement sensor output model is:

[0045] d i =-x i sinθ+y i sinφ+z0(i=1,2,...,9)

[0046] Where θ and φ are the pitch and roll angles, x i and y i is the coordinate of the displacement sensor on the XY plane, z0 is the overall vertical displacement of the hub. The coordinate of the outer ring sensor is x i =Rcosα i (i=1,2,3,4,5,6),y i =Rsinα i (i=1,2,3,4,5,6), α i =[ω α ,ω α +60°,-(60°-ω α ),-ω α ,-(60°+ω α ),60°-ω α ]; the inner circle sensor coordinate is x i =rcosα i (i=7,8,9),y i =rsinα i (i=7,8,9), α i =[ω β ,-(60°-ω β ),120°-ω β ].

[0047] The steps for calculating the attitude angle are as follows:

[0048] 1) Eliminate the overall displacement z0, the formula is The relative displacement is Δd i =d i -z0;

[0049] 2) Solve the attitude angle through the overdetermined equation

[0050]

[0051] The solution is

[0052]

[0053] 3) The heading angle calculation formula is:

[0054]

[0055] Among them, h i is the radial displacement of the outer ring sensor.

[0056] The present embodiment will be further described below in conjunction with a specific rotor attitude and vibration control system.

[0057] like Figure 3 As shown, the system's acquisition sensors include a 9-channel displacement sensor to measure rotor attitude angles (roll, pitch, and heading), a 6-channel accelerometer to measure the rotor's overall low- and medium-frequency vibrations (10-100 Hz), and a 3-channel encoder to measure rotor speed. After synchronously acquiring 18 channels of signals, the data is sent to the FPGA for signal distribution and processing. This involves data transmission to the DSP chip using the EMIF bus and SERDES technology, and the sensor signals are decoded, processed, and analyzed before being transmitted to the real-time monitoring system (host computer) via Ethernet. Simultaneously, the calculated rotor attitude and other signals are communicated with the flight control system via the RS422 serial port. The flight control system issues control commands to the servo based on the difference between the actual and target attitude angles, and references rotor vibration and speed signals. After the servo executes the command, the real-time monitoring system displays and saves the rotor status before and after the execution. The 18-channel sensors synchronously acquire the rotor status after the command is executed, providing real-time measurement, monitoring, and control. If the actual attitude angle does not differ from the target attitude angle and the vibration level is low, the flight control system does not issue a new control command.

[0058] Among them, 6-channel accelerometers and 3-channel encoders are used to measure the vibration and speed signals of the rotor as a reference for adjusting the rotor attitude angle. Among them, 3 accelerometers are used to measure the vibration of the main rotor hub, covering the layout of the lateral, axial and radial directions, and are used to capture the first-order or high-order frequency harmonic vibration signals formed by the rotor speed; 3 accelerometers are used to measure the vibration of the blade root, covering the layout of the lateral, axial and radial directions, and are used to capture modal vibrations including blade flapping and asymmetric unbalanced load vibrations. The final vibration level can be calculated by the following method:

[0059] The vibration amplitudes of the vibration signals in the three directions of the hub are extracted respectively, and the vibration amplitude of the hub is obtained by taking the square root of the sum of the squares.

[0060] The vibration amplitudes of the vibration signals in three directions of the blade root are extracted respectively, and the root sum of squares is taken to obtain the vibration amplitude of the blade root.

[0061] The vibration amplitudes of the hub and blade root are weighted averaged or the maximum value is taken as the final vibration amplitude A. V .

[0062] The rotor speed is measured by three encoders, which are installed on the main rotor drive shaft, the main reducer input end and the main reducer output end respectively. They are used to measure the rotor shaft speed, monitor the engine output shaft speed and redundantly monitor the rotor shaft speed.

[0063] After synchronous acquisition, the analog signal is processed before being used for calculation. The specific processing circuit includes an overload protection circuit, high- and low-pass filters, and a gain control circuit. The overload protection circuit ensures that the circuit does not overload, thereby improving system reliability. The high- and low-pass filters primarily filter out frequency components outside the system's high-bandwidth range. The gain control circuit is used to reduce noise and enhance common-mode voltage suppression. The embedded software uses an FPGA + DSP architecture for sensor signal acquisition and processing. The FPGA handles the real-time and highly parallel parts, including signal acquisition, data packaging, transmission, and filtering. The DSP is responsible for signal processing, including signal filtering, signal analysis, and attitude angle calculation.

[0064] The rotor attitude control algorithm performs PID (proportional, integral and differential) closed-loop feedback dynamic adjustment based on the rotor speed and vibration level, as well as the error between the actual attitude angle and the target attitude angle, to reduce the error between the actual attitude angle and the desired attitude angle while ensuring that the vibration level does not exceed the set value, such as 0.5g.

[0065] like Figure 4As shown, r(t) is the target value, including the vibration level less than 0.5g and the attitude angle error less than 0.1°, d(t) is the actual measured and calculated value, and y(t) is the controlled torque. The formula is where k p , k i and k d is the adjustment parameter, k V is the vibration compensation coefficient, A V is the vibration amplitude, and e(t) is the error between the desired attitude and the actual attitude. After collecting and calculating the vibration signal and solving the attitude angle, the error is calculated against the target value. The flight control system controls the servo to issue a compensation command, which controls the rotor motor to control the speed difference and output a compensating torque. The vibration level, speed, and attitude angle are continuously monitored in real time. The current value is saved when the target value is reached.

[0066] In some preferred embodiments, real-time monitoring and vibration control display of the rotor can also be performed, specifically including interface display of real-time sensor data collection and settled signals, data storage and data playback. At the same time, parameter settings of the software and hardware systems can be performed, including channel parameter settings, rotor attitude control algorithm PID adjustment parameter settings, RS422 serial port communication settings, encoder channel settings, and filter settings; the interface display includes rotor attitude angle signals (roll angle, pitch angle and heading angle), vibration signals (hub and blade root), speed signals (main rotor drive shaft, main reducer input end and main reducer output end) and the error between the actual attitude angle and the target attitude angle.

[0067] A second embodiment of the present invention relates to a helicopter rotor attitude and vibration control system, comprising:

[0068] The first sensor unit is used to collect the displacement signal of the helicopter rotor hub;

[0069] The second sensor unit is used to collect vibration signals of the helicopter rotor hub and blade roots;

[0070] The third sensor unit is used to collect the rotation speed signal of the helicopter rotor;

[0071] A signal processing unit is used to calculate the real-time value of the rotor attitude angle based on the displacement signal of the rotor hub, and then calculate the attitude angle error between the real-time value and the target value; and is also used to calculate the vibration amplitude of the rotor based on the vibration signals of the rotor hub and the blade root;

[0072] A control unit, configured to calculate a PID control variable based on the attitude angle error and the vibration amplitude, and then generate a control instruction;

[0073] The servo is used to control the helicopter rotor to operate according to the target attitude while reducing the rotor noise level according to the control instructions issued by the control unit.

[0074] The first sensor unit, serving as the helicopter rotor attitude angle measurement system, consists of nine linear displacement sensors mounted on the rotor hub. Through multi-degree-of-freedom redundant measurement and a motion decoupling algorithm, it achieves high-precision measurement of roll, pitch, and heading angles. The nine displacement sensors are spatially redundantly mounted on two concentric circles, with six sensors arranged at 60° intervals on the outer circle and three sensors arranged at 120° intervals on the inner circle. The outer circle measures the rotor attitude in the radial (roll), axial (pitch), and tangential directions (heading), while the inner circle is less sensitive to heading angles, primarily enhancing the robustness of the roll / pitch angle calculation. A weighted average of the roll, pitch, and heading angles is taken to obtain the real-time attitude angle value, which is then compared with the target value to determine the real-time attitude angle error, e(t).

[0075] More specifically, the 9 displacement sensors are installed as follows Figure 2 As shown in Figure 1, the 6 displacement sensors of the outer ring (radius R) are installed on the outer flange of the hub, and the 3 displacement sensors of the inner ring (radius r) are installed on the central platform of the hub. The displacement sensor output model is:

[0076] d i =-x i sinθ+y i sinφ+z0(i=1,2,...,9)

[0077] Where θ and φ are the pitch and roll angles, x i and y i is the coordinate of the displacement sensor on the XY plane, z0 is the overall vertical displacement of the hub. The coordinate of the outer ring sensor is x i =Rcosα i (i=1,2,3,4,5,6),y i =Rsinα i (i=1,2,3,4,5,6), α i =[ω α ,ω α +60°,-(60°-ω α ),-ω α ,-(60°+ω α ),60°-ω α ]; the inner circle sensor coordinate is x i =rcosα i (i=7,8,9),y i =rsinα i (i=7,8,9), α i =[ω β ,-(60°-ω β ),120°-ωβ ].

[0078] The steps for calculating the attitude angle are as follows:

[0079] 4) Eliminate the overall displacement z0, the formula is The relative displacement is Δd i =d i -z0;

[0080] 5) Solve the attitude angle through the overdetermined equation

[0081]

[0082] The solution is

[0083]

[0084] 6) The heading angle calculation formula is:

[0085]

[0086] Among them, h i is the radial displacement of the outer ring sensor.

[0087] The second sensor unit and the third sensor unit serve as wing vibration and speed measurement systems, used to measure the vibration and speed signals of the rotor, and serve as a reference for adjusting the rotor attitude angle. The second sensor unit and the third sensor unit are composed of 6 accelerometers and 3 encoders respectively. Among them, 3 accelerometers are used to measure the vibration of the main rotor hub, covering the arrangement in the lateral, axial and radial directions, and are used to capture the first-order or high-order frequency harmonic vibration signals formed by the rotor speed; 3 accelerometers are used to measure the vibration of the blade root, also covering the arrangement in the lateral, axial and radial directions, and are used to capture modal vibrations including blade flapping and asymmetric unbalanced load vibrations. The final vibration level can be calculated by the following method:

[0088] The vibration amplitudes of the vibration signals in the three directions of the hub are extracted respectively, and the vibration amplitude of the hub is obtained by taking the square root of the sum of the squares.

[0089] The vibration amplitudes of the vibration signals in three directions of the blade root are extracted respectively, and the root sum of squares is taken to obtain the vibration amplitude of the blade root.

[0090] The vibration amplitudes of the hub and blade root are weighted averaged or the maximum value is taken as the final vibration amplitude A. V .

[0091] The rotor speed is measured by three encoders, which are installed on the main rotor drive shaft, the main reducer input end and the main reducer output end respectively. They are used to measure the rotor shaft speed, monitor the engine output shaft speed and redundantly monitor the rotor shaft speed.

[0092] The signal processing unit is used to process the collected sensor data and includes hardware acquisition circuits and embedded software. The hardware acquisition circuit is mainly used for analog signal acquisition from displacement sensors and accelerometers. The hardware acquisition circuit includes an overload protection circuit, high- and low-pass filters, and a gain control circuit. The overload protection circuit ensures that the circuit will not be overloaded, thereby improving system reliability. The high- and low-pass filters are mainly used to filter out frequency components outside the bandwidth of the system's high bandwidth range. The gain control circuit is used to reduce noise and enhance common-mode voltage suppression capabilities. The embedded software uses an FPGA+DSP architecture for sensor signal acquisition and processing. The FPGA is used to handle real-time and highly parallel parts, including signal acquisition, data packaging, transmission, and filtering. The DSP is used for signal processing, including signal filtering, signal analysis, and attitude angle calculation.

[0093] The control unit executes the rotor attitude control algorithm. Based on the rotor's speed and vibration level, as well as the error between the actual and target attitude angles, it dynamically adjusts the rotor using a PID (proportional, integral, and differential) closed-loop feedback system. This reduces the error between the actual and desired attitude angles while ensuring that the vibration level does not exceed a set value, such as 0.5g. The control unit is deployed in the flight control execution system, which consists of an RS422 serial communication port and a servo control module. Based on the rotor parameter information sent by the FPGA and the PID algorithm feedback, the flight control system determines the difference between the actual and target attitude angles. Taking into account the rotor's vibration and speed, it sends execution instructions to the actuator (servo), ensuring that the helicopter rotor operates at the target attitude while reducing rotor noise.

[0094] In some preferred embodiments, the system also includes a rotor real-time monitoring and vibration control display system. The monitoring and display system includes an interface display of real-time sensor data collection and settlement signals, data storage and data playback, and can also perform parameter settings on the software and hardware systems, including channel parameter settings, rotor attitude control algorithm PID adjustment parameter settings, RS422 serial port communication settings, encoder channel settings, and filter settings; the interface display includes rotor attitude angle signals (roll angle, pitch angle and heading angle), vibration signals (hub and blade root), speed signals (main rotor drive shaft, main reducer input and main reducer output) and the error between the actual attitude angle and the target attitude angle.

[0095] like Figure 3The system's acquisition sensors include a 9-channel displacement sensor for measuring rotor attitude angles (roll, pitch, and heading), a 6-channel acceleration sensor for measuring the rotor's overall low- and medium-frequency vibrations (10-100 Hz), and a 3-channel encoder for measuring rotor speed. After synchronously acquiring 18 channels of signals, the data is sent to the FPGA for signal distribution and processing, including data transmission to the DSP chip based on the EMIF bus and SERDES technology. The sensor-collected signals are then analyzed and processed, and then transmitted to the real-time monitoring system (host computer) via Ethernet. Simultaneously, the calculated rotor attitude and other signals are communicated with the flight control system via the RS422 serial port. The flight control system issues control commands to the servo based on the difference between the actual attitude angle and the target attitude angle, and references the rotor's vibration and speed signals. After the servo executes the command, the real-time monitoring system displays and saves the rotor status before and after execution. The 18-channel sensors synchronously acquire the rotor status after the command is executed, measuring, monitoring, and controlling the next step in real time. If there is no difference between the actual attitude angle and the target attitude angle and the vibration level is low, the flight control system does not issue a new control command.

[0096] Rotor attitude control algorithm such as Figure 4 As shown, r(t) is the target value, including the vibration level less than 0.5g and the attitude angle error less than 0.1°, d(t) is the actual measured and calculated value, and y(t) is the controlled torque. The formula is where k p , k i and k d is the adjustment parameter, k V is the vibration compensation coefficient, A V is the vibration amplitude, and e(t) is the error between the desired attitude and the actual attitude. After collecting and calculating the vibration signal and solving the attitude angle, the error is calculated against the target value. The flight control system controls the servo to issue a compensation command, which controls the rotor motor to control the speed difference and output a compensating torque. The vibration level, speed, and attitude angle are continuously monitored in real time. The current value is saved when the target value is reached.

[0097] The rotor real-time monitoring and vibration control display system includes: Figure 5 The display interface shown in the figure collects signals and solved signals in real time, including rotor attitude angle signals (roll angle, pitch angle and heading angle), vibration level signals (hub and blade root), speed signals (main rotor drive shaft, main reducer input end and main reducer output end), and the error between the actual rotor attitude angle and the target attitude angle.

Claims

1. A method for controlling the attitude and vibration of a helicopter rotor, characterized in that: The following steps are involved: Real-time acquisition of helicopter rotor hub displacement signals, hub and blade root vibration signals, and rotor speed signals; The real-time value of the rotor attitude angle is calculated based on the displacement signal of the rotor hub, and then the attitude angle error between the real-time value and the target value is calculated; The PID control variable is calculated based on the attitude angle error and the vibration amplitude of the rotor, and then a control instruction is generated to drive the servo to control the helicopter rotor to operate according to the target attitude while reducing the rotor noise level.

2. The method according to claim 1, characterized in that The PID control quantity is expressed as Among them, y(t) is the PID control quantity, e(t) is the attitude angle error, k p , k i and k d is the adjustment parameter, k V is the vibration compensation coefficient, A V is the vibration amplitude.

3. The method according to claim 1, characterized in that The displacement signal of the rotor hub is collected by six displacement sensors deployed on the outer flange of the helicopter rotor hub and three displacement sensors deployed on the central platform of the helicopter rotor hub.

4. The method according to claim 3, characterized in that The rotor attitude angle includes the roll angle, pitch angle and heading angle, which are calculated by the following formulas: Δd i =d i -z0 Among them, θ, φ and are pitch angle, roll angle and heading angle respectively, x i and y i are the coordinates of displacement sensor i on the XY plane, z0 is the overall vertical displacement of the hub, d i is the displacement of displacement sensor i, Δd i is the displacement of displacement sensor i relative to the hub, h i and α i are the radial displacement and central angle of the displacement sensor deployed on the outer flange of the helicopter rotor hub.

5. The method according to claim 4, characterized in that The real-time value of the rotor attitude angle is obtained by weighted averaging the roll angle, pitch angle and heading angle calculated in real time.

6. The method according to claim 1, characterized in that The vibration amplitude of the rotor is obtained by calculating the vibration amplitudes of the hub and the blade root according to the vibration signals of the hub and the blade root respectively, and then performing weighted averaging or taking the maximum value thereof.

7. A helicopter rotor attitude and vibration control system, characterized in that: include: The first sensor unit is used to collect the displacement signal of the helicopter rotor hub; The second sensor unit is used to collect vibration signals of the helicopter rotor hub and blade roots; The third sensor unit is used to collect the rotation speed signal of the helicopter rotor; A signal processing unit is used to calculate the real-time value of the rotor attitude angle based on the displacement signal of the rotor hub, and then calculate the attitude angle error between the real-time value and the target value; and is also used to calculate the vibration amplitude of the rotor based on the vibration signals of the rotor hub and the blade root; A control unit, configured to calculate a PID control variable based on the attitude angle error and the vibration amplitude, and then generate a control instruction; The servo is used to control the helicopter rotor to operate according to the target attitude according to the control instructions while reducing the rotor noise level.

8. The system according to claim 7, characterized in that The first sensor unit includes 9 displacement sensors, 6 of which are deployed on the outer edge flange of the helicopter rotor hub, and 3 of which are deployed on the central platform of the helicopter rotor hub.

9. The system according to claim 8, characterized in that The displacement sensors deployed on the outer flange of the hub and the central platform of the helicopter rotor hub are distributed at equal intervals on the first circumference and the second circumference, and the first circumference and the second circumference both have the axis of the rotor main shaft as the center of the circle.

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