Aircraft propeller wireless variable pitch control system and method

Abstract

The application discloses an airplane propeller wireless variable-pitch control system and method, and the system comprises a control panel, a controller, a coupling coil group, an electric steering engine, an angle sensor, a rechargeable battery, a battery state sensor, a high-frequency signal generation module, a fuselage battery and a high-frequency oscillator. The control system and method provided by the application adopt the electric steering engine as a variable-pitch actuating mechanism to provide variable-pitch power, and the feedback information of the electric steering engine can reflect the actual rotating angle, speed, temperature and other information of the electric steering engine. The controller can accurately adjust the output control signal according to the feedback information of the electric steering engine, and then adjust the rotating angle of the electric steering engine, so that the variable-pitch error of the propeller is reduced to the maximum extent, and the variable-pitch precision is improved.

Description

A wireless pitch control system and method for aircraft propellers Technical Field

[0001] This invention relates to the field of aviation wireless pitch control technology, and in particular to a wireless pitch control system and method for aircraft propellers. Background Technology

[0002] The core design principle of an aircraft propulsion system is to ensure high propeller efficiency throughout flight. This primarily involves designing a perfect control and distribution method to maximize the energy absorbed by the propeller from the engine, thereby maximizing the overall efficiency of the aircraft. There are many methods to improve propeller efficiency. Flight tests have shown that the application of variable pitch propellers significantly improves the aircraft's adaptability and greatly enhances the aircraft's power absorption from the propeller. The application of variable pitch propellers improves the efficiency of the propulsion system, resulting in significant improvements in the aircraft's maneuverability, endurance, and overall system efficiency.

[0003] Currently, aircraft propeller electric pitch control systems typically use conductive slip rings to connect the aircraft fuselage to the high-speed rotating propeller, providing electrical power and transmitting signals to the pitch motor. Due to the complex operating environment of aircraft, the slip ring material must possess high impact toughness, corrosion resistance, wear resistance, and be resistant to accidental dragging or contact. Compared to using slip rings for power and signal transmission, wireless power and signal transmission technology offers numerous advantages, including non-contact operation, no wear, and flexibility. Wireless propeller electric pitch control systems offer advantages such as smaller size, lighter weight, and higher control precision compared to current electric pitch control systems. Furthermore, the wireless pitch control system effectively avoids problems such as excessively high surface temperatures of the conductive slip ring caused by prolonged high-speed rotation of the aircraft propeller, which could lead to overheating failures of the conductive slip ring and brushes.

[0004] Therefore, it is of great significance to provide a wireless pitch control system and method for aircraft propellers. Summary of the Invention

[0005] In view of this, the present invention discloses a wireless pitch control system and method for aircraft propellers to improve the efficiency of aircraft propulsion systems.

[0006] The technical solution provided by the present invention is as follows: Firstly, the present invention provides a wireless pitch control system for an aircraft propeller, including a control panel, a controller, a coupling coil group, an electric servo, an angle sensor, a rechargeable battery, a battery status sensor, a high-frequency signal generation module, a fuselage battery, and a high-frequency oscillator.

[0007] The control panel is signal-connected to the controller and is used to switch the controller's control mode; the controller is signal-connected to the electric servo motor and rechargeable battery through a coupling coil group and is used to send drive control signals to the electric servo motor and rechargeable battery.

[0008] The angle sensor and battery status sensor are connected to the controller via a coupling coil group to send feedback signals to the controller; the feedback signals are rotation angle feedback signals and battery status feedback signals.

[0009] The aircraft fuselage battery is connected to a high-frequency oscillator, which is used to generate AC power signals. The high-frequency signal generation module and the high-frequency oscillator are respectively connected to a power amplifier, and the controller is connected to the high-frequency signal generation module.

[0010] The display screen is connected to the controller and is used to show the flight status.

[0011] Furthermore, the auxiliary power conversion circuit includes a 15V voltage regulator chip, a 5V conversion chip, and a 3.3V conversion chip. The input terminal of the 15V voltage regulator chip is connected to a 15V power supply, the input terminal of the 5V conversion chip is connected to the output terminal of the 15V voltage regulator chip, and the input terminal of the 3.3V conversion chip is connected to the output terminal of the 5V conversion chip.

[0012] The control panel 1 includes an automatic / manual control joystick S1, a take-off / landing switch S2, a climb switch S3, a cruise switch S4, a hold switch S5, and a feathering switch S6. The stationary contact of the automatic / manual control joystick S1 is connected to the PA0 pin of the controller, and the moving contact of the automatic / manual control joystick S1 is connected to ground or a resistor, with the other end of the resistor connected to a 3.3V power supply. The take-off / landing switch S2 is connected to the 22.0 pin of the controller, the climb switch S3 is connected to the PC13 pin of the controller, the cruise switch S4 is connected to the PE3 pin of the controller, the hold switch S5 is connected to the PA0 pin of the controller U4, and the feathering switch S6 is connected to the PB11 pin of the controller U4. The system is grounded through an operating switch, which is connected to the PG15 pin of the controller through its control panel.

[0013] On the other hand, the present invention provides a method for controlling the wireless pitch change of an aircraft propeller using the system described above, comprising the following steps:

[0014] Step 1: The AC power signal generated by the high-frequency oscillator and the control signal generated by the signal generation module are both passed through the power amplifier;

[0015] Step 2: The power amplifier transmits the generated high-frequency energy signal to the coupling coil and then to the transmitting coil. The receiving coil couples the energy signal in the magnetic field and converts it into the charging current of the battery used by the DC load and the drive signal of the servo motor through the extraction and rectification device.

[0016] S3: Change the control signal output by the controller through the control panel. The control signal is delivered to the servo motor through the coupling coil group, thereby changing the servo motor drive signal. The servo motor starts to rotate the corresponding angle to realize the switching of flight state.

[0017] S4: The rotation angle feedback signal generated by the sensor on the servo motor and the battery status feedback signal generated by the battery status sensor in the battery module are jointly transmitted to the controller through the coupling coil group;

[0018] S5: The controller further adjusts the output control signal precisely based on the feedback signal and displays it on the display screen.

[0019] The servo drive signal uses RS485 communication.

[0020] This invention provides a wireless pitch control system and method for aircraft propellers. It uses an electric servo motor to provide pitch control power to the pitch actuator. The feedback information from the electric servo motor can reflect the actual rotation angle, speed, temperature, and other information of the electric servo motor. The controller can accurately adjust the output control signal based on the feedback information from the electric servo motor, thereby adjusting the rotation angle of the electric servo motor, minimizing the pitch error of the propeller and improving the pitch accuracy.

[0021] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the disclosure of the present invention. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 is a structural diagram of the wireless pitch control system for aircraft propellers provided by the present invention.

[0025] Figure 2 is a schematic diagram of the servo motor described in this invention;

[0026] Figure 3 is a pin schematic diagram of the STM32F103ZET6 controller chip described in this invention.

[0027] Figure 4 is a schematic diagram of the 485 communication chip used in this invention. Detailed Implementation

[0028] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of systems consistent with some aspects of the invention as detailed in the appended claims.

[0029] To address the problems of overheating faults in the conductive slip rings and brushes in existing electric pitch control systems, as shown in Figure 1, this implementation provides a wireless pitch control system for aircraft propellers, including a control panel 1, a controller 2, a coupling coil group 3, an electric servo motor 41, an angle sensor 42, a rechargeable battery 51, a battery status sensor 52, a high-frequency signal generation module 7, a fuselage battery 8, and a high-frequency oscillator 9.

[0030] The control panel 1 is signal-connected to the controller 2 and is used to switch the control mode of the controller 2; the controller 2 is signal-connected to the electric servo motor 41 and the rechargeable battery 51 through the coupling coil group 3 and is used to send drive control signals to the electric servo motor 41 and the rechargeable battery 51.

[0031] The angle sensor 42 and the battery status sensor 52 are signal-connected to the controller 2 via the coupling coil group 3, and are used to send feedback signals to the controller 2; the feedback signals are rotation angle feedback signals and battery status feedback signals.

[0032] The aircraft fuselage battery 8 is connected to the high-frequency oscillator 9, which is used to generate AC power signals. The high-frequency signal generation module 7 and the high-frequency oscillator 9 are respectively connected to the power amplifier 10. The controller 2 is connected to the high-frequency signal generation module 7.

[0033] Display screen 6 is connected to controller 2 and is used to display flight status.

[0034] The system also includes an auxiliary power conversion circuit, which includes a 15V voltage regulator chip, a 5V conversion chip, and a 3.3V conversion chip. The input terminal of the 15V voltage regulator chip is connected to a 15V power supply, the input terminal of the 5V conversion chip is connected to the output terminal of the 15V voltage regulator chip, and the input terminal of the 3.3V conversion chip is connected to the output terminal of the 5V conversion chip.

[0035] Figure 3 shows the pin diagram of the controller used in this embodiment. The control panel 1 includes an automatic / manual control joystick S1, a take-off / landing switch S2, a climb switch S3, a cruise switch S4, a hold switch S5, and a feathering switch S6. The stationary contact of the automatic / manual control joystick S1 is connected to the PA0 pin of the controller, and the moving contact of the automatic / manual control joystick S1 is connected to ground or a resistor. The other end of the resistor is connected to a 3.3V power supply. The take-off / landing switch S2 is connected to the 22.0 pin of the controller, the climb switch S3 is connected to the PC13 pin of the controller, the cruise switch S4 is connected to the PE3 pin of the controller, the hold switch S5 is connected to the PA0 pin of the controller U4, and the feathering switch S6 is connected to the PB11 pin of the controller U4. The system is grounded through the control switch, and the control switch is connected to the PG15 pin of the controller through its control panel.

[0036] Through the aforementioned control circuit, the aircraft propeller wireless pitch control system can achieve two control modes: manual and automatic. The corresponding control mode can be selected via a switch. In manual mode, the propeller pitch can be changed in real time by manipulating a joystick. In automatic mode, five position switches are set for takeoff / landing, climb, cruise, hold, and feathering. The takeoff / landing, climb, and feathering switches correspond to fixed pitch angles; pressing the corresponding switch adjusts the propeller pitch up to the desired pitch angle. The cruise switch corresponds to the aircraft's cruise flight state; when the cruise switch is pressed, the controller uses the airspeed indicator... The collected flight speed information is used to calculate the optimal propeller pitch angle and send the adjustment control signal to the electric servo. The electric servo has a feedback signal output interface that can output information such as the servo's rotation angle, speed, and temperature. This feedback data is sent to the controller, which processes the received feedback information and displays it on the screen in real time. Based on this feedback, the controller adjusts the electric servo, such as increasing or decreasing the rotation angle, thereby maximizing the propeller pitch accuracy. When the hold switch is pressed, the current propeller pitch remains unchanged.

[0037] Preferably, the controller is an STM32F103ZET6, the battery is a JUHAI35C, the electric servo motor is an SM60CL, the battery status sensor is a Yuanzheng 5-15V, and the display screen is an ILI9341.

[0038] The controller is connected to a 5V power supply, the battery charging voltage is 4.2V, the electric servo motor input voltage is 12V, the angular velocity sensor power supply voltage is 3-5V, and the battery status sensor 52 input voltage is 2.2-5V.

[0039] The coupling coil group used in this implementation adopts a frequency division multiplexing (FDM) wireless power and signal synchronization transmission system structure, including a FDM wireless power and signal forward synchronization transmission system structure and a FDM wireless power and signal reverse synchronization transmission system structure. The power supply frequency is assumed to be the frequency that allows the system to reach resonance. The power transmission process is as follows: the alternating power source generates low-frequency power, which is wirelessly transmitted to the secondary resonant circuit inductor coil via coupling through the primary resonant circuit inductor coil, and then transmitted through the secondary resonant circuit to power the power load. The signal transmission process is as follows: the signal source outputs a modulated signal, which is wirelessly transmitted to the primary resonant circuit inductor coil via coupling through the transmitting circuit inductor coil, and the signal acquisition module acquires the signal from the primary resonant circuit.

[0040] Further optimization revealed that the servo control signal uses RS485 communication, which features support for multiple nodes (32 nodes), long transmission distance (maximum 1219m), high receiving sensitivity (200mV voltage), simple connection (only one pair of twisted-pair cables is needed as the transmission line when forming a communication network), suppression of common-mode interference (differential transmission), and low cost. It has been widely used in various industrial control environments such as multi-station and long-distance communication.

[0041] In an RS485 communication network, a RS485 transceiver is typically used to convert TTL levels into RS485 differential signals. The MCU's serial port controller (TxD) sends data, which is converted into differential signals by the RS485 transceiver and transmitted to the bus. When receiving data, the RS485 transceiver converts the differential signals on the bus back into TTL signals, which are then transmitted from RxD to the serial port controller. Typically, there is only one master in the entire communication network, with the rest being slaves. In an RS485 bus, approximately 120Ω terminating resistors are usually added at the start and end points of the bus to ensure its stability. The controller's USART2_RX pin is connected to the RO and DI pins of the RS485 chip. Figure 4 shows the schematic of the RS485 section of the development board. U16 is a 3.3V low-power half-duplex transceiver that meets the RS-485 standard. The USART's RX and TX pins are converted by U16 to become the RS485 A and B ports. Pin 2 (RE) of U16 is the receive enable, and the overline indicates that it is active low. That is, when pin 2 of U16 is low, U16 receives data. Pin 3 (DE) of U16 is the output enable, and it is active high. That is, when pin 3 of U16 is high, U16 transmits data.

[0042] The controller's USART2_RX and USART2_RX pins are connected to the RO and DI pins of the RS485 chip. Figure 4 shows the schematic diagram of the RS485 section of the development board. U16 is a 3.3V low-power half-duplex transceiver that meets the RS-485 standard. The USART's RX and TX pins are converted to RS485 A and B pins by U16. Pin 2 (RE) of U16 is the receive enable pin; the overline indicates that it is active low, meaning that U16 receives data when pin 2 is low. Pin 3 (DE) of U16 is the output enable pin; it is active high, meaning that U16 transmits data when pin 3 is high.

[0043] Further optimization yielded the SM-60CL electric servo motor, a 12V serial bus intelligent servo motor featuring an all-aluminum alloy casing, brushless motor, steel gearbox, RS485 control board, 12-bit high-precision magnetic encoder sensor, and external stainless steel main servo disc. It has a stall torque of 60 kg·cm, enabling 360-degree controllable rotation, multi-turn continuous rotation, and one-button setting of the neutral position. It also features acceleration soft start and soft stop, and can provide feedback on position, speed, current, voltage, temperature, and load parameters, thus achieving overload and overcurrent protection.

[0044] The aforementioned wireless pitch control system for aircraft propellers also incorporates parameter design for the power and signal transmission circuits based on the varying impedance characteristics at different frequencies, ensuring high impedance characteristics at each other's transmission frequencies. Furthermore, using coupling coils to construct the signal acquisition and processing module effectively filters out interference from low-frequency power, improving the signal-to-noise ratio. This allows for low-interference synchronous transmission of power and signals with only simple modifications to the wireless power transmission circuit topology. Secondly, to increase the signal transmission rate, the carrier frequency must be as high as possible. According to the LC circuit resonant frequency calculation formula, since the capacitor C has an adjustable lower limit, increasing the carrier frequency requires reducing the coil inductance L, which can be achieved by flexibly selecting the size of some coil sections.

[0045] The method for controlling the wireless pitch of an aircraft propeller using the above system includes the following steps:

[0046] Step 1: The AC power signal generated by the high-frequency oscillator 9 and the control signal generated by the signal generation module are jointly passed through the power amplifier 10;

[0047] Step 2: The power amplifier 10 transmits the generated high-frequency energy signal to the coupling coil and then to the transmitting coil. The receiving coil couples the energy signal in the magnetic field and converts it into the charging current of the battery 51 used by the DC load and the drive signal of the servo motor 41 through the extraction and rectification device.

[0048] Step 3: Change the control signal output by the controller 2 through the control panel 1. The control signal is delivered to the servo motor through the coupling coil group 3, thereby changing the servo motor drive signal. The servo motor starts to rotate the corresponding angle to realize the switching of flight state.

[0049] Step 4: The rotation angle feedback signal generated by the sensor 42 on the servo motor and the battery status feedback signal generated by the battery status sensor 52 in the battery module are jointly transmitted to the controller through the coupling coil group 3.

[0050] Step 5: The controller 2 further adjusts the output control signal precisely based on the feedback signal and displays it on the display screen.

[0051] The wireless pitch control system for aircraft propellers in this implementation uses wireless power and signal transmission to provide power to the pitch control servo and transmit and receive control commands. Compared with the use of conductive slip rings, this solution has many advantages such as non-contact operation, no wear, and flexibility. Compared with current electric pitch control systems, the wireless propeller electric pitch control system has advantages such as small size, light weight, and high control precision. Furthermore, the wireless pitch control system effectively avoids problems such as excessively high surface temperature of the conductive slip ring caused by prolonged high-speed rotation of the aircraft propeller, leading to overheating failures of the conductive slip ring and brushes.

[0052] The electric variable-pitch propeller control system of this implementation uses a microcontroller as the core chip of the control system, which significantly improves the response speed and control efficiency of the controller, achieving the purpose of real-time control and real-time response. Through the wireless power and signal transmission via the coupling coil, the control signal output by the controller can be transmitted to the electric servo motor, and the feedback signal of the electric servo motor can be transmitted to the controller. After processing by the controller, it can be displayed in real time on the display screen.

[0053] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

Claims

1. A wireless pitch control system for an aircraft propeller, characterized in that, The system includes a control panel (1), a controller (2), a coupling coil group (3), an electric servo motor (41), an angle sensor (42), a rechargeable battery (51), a battery status sensor (52), a high-frequency signal generation module (7), a fuselage battery (8), and a high-frequency oscillator (9). The control panel (1) is signal-connected to the controller (2) and is used to switch the control mode of the controller (2). The controller (2) is connected to the electric servo motor (41) and the rechargeable battery (51) through the coupling coil group (3) and is used to send drive control signals to the electric servo motor (41) and the rechargeable battery (51). The angle sensor (42) is also connected to the controller (2). Sensor (42) and battery status sensor (52) are connected to controller (2) via coupling coil group (3) to send feedback signals to controller (2); the feedback signals are rotation angle feedback signals and battery status feedback signals; the aircraft fuselage battery (8) is connected to high frequency oscillator (9), which is used to generate AC power signals; the high frequency signal generation module (7) and high frequency oscillator (9) are respectively connected to power amplifier (10); the controller (2) is connected to high frequency signal generation module (7); the display screen (6) is connected to controller (2) to display flight status.

2. The wireless pitch control system for an aircraft propeller according to claim 1, characterized in that, It also includes an auxiliary power conversion circuit, wherein the auxiliary power conversion circuit includes a 15V voltage regulator chip, a 5V conversion chip and a 3.3V conversion chip, wherein the input terminal of the 15V voltage regulator chip is connected to a 15V power supply, the input terminal of the 5V conversion chip is connected to the output terminal of the 15V voltage regulator chip, and the input terminal of the 3.3V conversion chip is connected to the output terminal of the 5V conversion chip.

3. The wireless pitch control system for an aircraft propeller according to claim 1, characterized in that, The control panel (1) includes an automatic / manual control joystick S1, a take-off and landing switch S2, a climb switch S3, a cruise switch S4, a hold switch S5, and a feathering switch S6. The stationary contact of the automatic / manual control joystick S1 is connected to the PA0 pin of the controller, and the moving contact of the automatic / manual control joystick S1 is connected to ground or a resistor. The other end of the resistor is connected to a 3.3V power supply. The take-off and landing switch S2 is connected to the PF10 pin of the controller, the climb switch S3 is connected to the PC13 pin of the controller, the cruise switch S4 is connected to the PE3 pin of the controller, the hold switch S5 is connected to the PA0 pin of the controller U4, and the feathering switch S6 is connected to the PB11 pin of the controller (2). The system is grounded through the control switch, and the control switch is connected to the PG15 pin of the controller through its control panel.

4. A method for controlling the wireless pitch variation of an aircraft propeller using the system described in any one of claims 1-3, characterized in that, The process includes the following steps: Step 1: The high-frequency oscillator (9) generates an AC power signal, which, together with the control signal generated by the signal generation module, passes through the power amplifier (10); Step 2: The power amplifier (10) transmits the generated high-frequency energy signal to the coupling coil and the transmitting coil. The receiving coil is coupled in the magnetic field to obtain the energy signal, which is converted into the charging current of the battery (51) used by the DC load and the driving signal of the electric servo (41) through the extraction and rectification device; S3: The control signal output by the controller (2) is changed through the control panel (1). The control signal is delivered to the servo through the coupling coil group (3), thereby changing the servo drive signal. The servo starts to rotate the corresponding angle to realize the switching of the flight state; S4: The angle sensor (42) on the servo generates a rotation angle feedback signal, and the battery status sensor (52) in the battery module generates a battery status feedback signal, which is transmitted to the controller through the coupling coil group (3); S5: The controller (2) further adjusts the output control signal according to the feedback signal and displays it on the display screen.

5. The control method for wireless pitch control of an aircraft propeller according to claim 4, characterized in that, The servo drive signal uses RS485 communication.

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