A crosswise double tilt-rotor aircraft flight control system

Abstract

The present invention relates to a fly-by-wire system for a tandem tilt-rotor aircraft. It consists of a flight control system, a tilt control system, and an information acquisition system. The three systems communicate via an RS485 bus. The flight control system, tilt control system, and information acquisition system respectively control the flight of the aircraft, the tilt of the rotor nacelle, and the engine speed, reducing the complexity of a single system. At the same time, each system is separately installed near the controlled object to prevent interference caused by too long signal lines. In the flight control system, all information acquisition and transmission tasks are implemented by the FPGA chip and the surrounding circuits. The airborne computer only focuses on the operation of the control algorithm, improving the utilization efficiency of the airborne computer and providing reliable support for adding more complex control algorithms. In the tilt control system, the tilt angle of the rotor nacelle is measured by using a resolver, which has the characteristics of simple installation, high precision, and fast response.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft control, and more particularly, to a fly-by-wire system for a tandem dual-rotor tilt-rotor aircraft. Background Art

[0002] A vertical takeoff and landing fixed-wing aircraft is an aircraft that combines the characteristics of a helicopter's vertical takeoff and landing and a fixed-wing aircraft's high-speed cruise. Existing vertical takeoff and landing fixed-wing aircraft mainly include types such as quadrotor compound wings, quadrotor tilt-rotors, and tandem dual-rotor tilt-rotors. Among them, the quadrotor compound wing is the mainstream vertical takeoff and landing fixed-wing aircraft due to its simple structure and control. For the tandem dual-rotor tilt-rotor, compared with the quadrotor, it has two fewer rotors and rotating mechanisms, and two fewer rotor power consumptions, resulting in a lower overall consumption and stronger endurance. The direct benefit is that its carrying capacity is significantly improved compared to the traditional quadrotor under the same volume, and the load capacity is also greater.

[0003] However, the structure and composition of the fly-by-wire system for the tandem dual-rotor tilt-rotor are complex. Its fly-by-wire system needs to simultaneously control the helicopter state servo and the fixed-wing state servo, and also needs to monitor and control the tilt angle of the rotor nacelle, and control the engine speed in both the helicopter and fixed-wing states. Therefore, it is necessary to improve the fly control circuit structure to solve this problem. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a fly-by-wire system for a tandem dual-rotor tilt-rotor aircraft, which can control the helicopter state machine and the fixed-wing state servo, monitor and control the tilt angle of the rotor nacelle, and control the engine speed according to requirements.

[0005] The technical solution adopted by the present invention to achieve the above object is as follows:

[0006] A fly-by-wire system for a tandem dual-rotor tilt-rotor aircraft, comprising: a flight control system provided on the aircraft body, and a tilt control system and an information acquisition system connected thereto through a bus;

[0007] The flight control system includes an FPGA chip and a flight control airborne computer, a sensor group, a digital frequency hopping radio, a helicopter servo, and a fixed-wing servo respectively connected thereto; the flight control system is connected to a ground station through the digital frequency hopping radio; the FPGA chip reads ground station instructions, sensor data, ECU data, gearbox temperature and pressure data collected by the information acquisition system, and the actual tilt angle of the nacelle collected by the tilt control system and sends them to the flight control airborne computer; the flight control airborne computer receives data and instructions, outputs speed control quantity signals for the helicopter servo and the fixed-wing servo, and outputs a desired tilt angle signal for the nacelle and a desired speed signal for the engine;

[0008] The tilt control system includes a tilt on-board computer, a modulation and demodulation chip, and a tilt motor that are respectively connected thereto. The modulation and demodulation chip is also connected to a tilt angle sensor. The modulation and demodulation chip collects the cos / sin signals of the resolver and converts them into angle signals and sends them to the tilt on-board computer. The tilt on-board computer collects the angle signals and converts them into the actual tilt angle of the nacelle. According to the desired tilt angle of the nacelle, through the PID control algorithm, it outputs the rotation speed of the tilt motor to control the rotation of the tilt motor.

[0009] The information acquisition system includes an information acquisition on-board computer, an engine ECU, a nacelle gearbox oil temperature sensor, a nacelle gearbox oil pressure sensor, and a throttle servo that are respectively connected thereto. The throttle servo controls the engine speed of the aircraft. The on-board computer collects the gearbox temperature and pressure data and the ECU speed data. According to the desired engine speed, through the PID control algorithm, it outputs the speed control amount of the throttle servo, which is converted into a PWM signal to control the throttle servo to keep the engine speed constant at the set value.

[0010] The flight control system, the tilt control system, and the information acquisition system communicate with each other through a 485 bus.

[0011] The sensor group includes a differential pressure sensor + pitot tube module, an inertial measurement unit, a barometric pressure sensor, a satellite positioning module, and a magnetic compass, which respectively collect airspeed data, three-axis acceleration and angle data, barometric altitude data, real-time position data, and heading data.

[0012] The FPGA chip is connected to the barometric pressure sensor, the satellite positioning module, the magnetic compass, and the digital frequency hopping radio through an RS232 interface, and is connected to the differential pressure sensor + pitot tube module, the inertial measurement unit, the barometric pressure sensor, and the flight control on-board computer through an SPI bus, and is connected to the helicopter servo and the fixed-wing servo through a PWM port.

[0013] The helicopter servo is connected to the helicopter swashplate, and the fixed-wing servo is connected to the fixed-wing control surface. The PWM port outputs a PWM signal to control the helicopter swashplate and the fixed-wing control surface.

[0014] The tilt angle sensor is a resolver and is installed on the nacelle rotating shaft.

[0015] The oil temperature sensor and the oil pressure sensor are arranged in the nacelle gearbox.

[0016] The tilt on-board computer is connected to the tilt motor through an RS232 interface and is connected to the modulation and demodulation chip through an SPI bus. The modulation and demodulation chip is connected to the tilt angle sensor through a signal line.

[0017] The information acquisition and conversion computer is connected to the engine ECU through the RS232 interface, connected to the gearbox lubricating oil temperature sensor and the nacelle gearbox lubricating oil pressure sensor through the RS232 interface, and connected to the throttle servo through the PWM port.

[0018] The present invention has the following beneficial effects and advantages:

[0019] 1. By separately improving the control circuits for the flight of the aircraft, the tilting of the rotor nacelle, and the engine speed through the flight control system, the tilting control system, and the information acquisition system, the complexity of a single system is reduced. At the same time, the circuits of each system are separately installed near the controlled object to prevent interference caused by too long signal lines.

[0020] 2. All information acquisition and transmission tasks in the flight control system are implemented by the FPGA chip and the surrounding circuits. The flight control on-board computer only focuses on the operation of the control algorithm, improving the utilization efficiency of the flight control on-board computer and providing reliable support for adding more complex control algorithms.

[0021] 3. The tilting control system measures the tilting angle of the rotor nacelle by using a resolver, featuring simple installation, high precision, and fast response. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the system structure diagram of the present invention;

[0023] Figure 2 is the structure diagram of the flight control system in the present invention;

[0024] Figure 3 is the structure diagram of the tilting control system in the present invention;

[0025] Figure 4 is the structure diagram of the information acquisition system in the present invention;

[0026] Figure 5 is the schematic diagram of a tandem dual-rotor tilting aircraft. DETAILED DESCRIPTION OF THE INVENTION

[0027] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the following describes the specific implementation method of the present invention in detail with reference to the drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the invention. Therefore, the present invention is not limited by the specific implementations disclosed below.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the invention herein are for the purpose of describing specific embodiments only and are not intended to limit the invention.

[0029] As Figure 1 shown, the flight control system of the tandem double tilt-rotor aircraft includes a flight control system, a tilt control system, and an information acquisition system; the flight control system communicates with the tilt control system through an RS485 bus, and the flight control system sends the expected tilt angle of the UAV nacelle to the tilt control system, and the tilt control system sends the actual tilt angle of the nacelle to the flight control system. The flight control system communicates with the information acquisition system through an RS485 bus, and the flight control system sends the expected engine speed to the information acquisition system, and the information acquisition system sends the collected ECU data, gearbox temperature and pressure data to the flight control system.

[0030] As Figure 2 shown, the flight control system includes an airborne computer, a field programmable gate array (FPGA) chip, sensors, a digital frequency hopping radio, a helicopter servo, and a fixed-wing servo. The airborne computer is STM32H743, the FPGA chip is EP4CE10E22, and the sensors are NEO-M8N satellite positioning module, HMR2300 magnetic compass, DO4525 differential pressure sensor + pitot tube module, ADIS16448 inertial measurement unit, and barometric pressure sensor. The helicopter servo is SF40035MG, and the fixed-wing servo is DA26-30.

[0031] As Figure 2As shown in the figure, the FPGA chip reads the airspeed data of the DO4525 differential pressure sensor + pitot tube module through the SPI bus, reads the three-axis acceleration and angular velocity data of the inertial measurement unit, and reads the barometric altitude data of the barometric pressure sensor. It reads the position and velocity data of the satellite positioning module through RS232, reads the heading data of the magnetic compass, and reads the ground personnel control instructions received by the frequency hopping radio. It reads the ECU data, gearbox temperature and pressure data collected by the information acquisition system through the RS485 bus, and reads the actual nacelle tilt angle collected by the tilt control system. Then it packs all the data and sends it to the airborne computer through the SPI bus at a frequency of 50HZ. The airborne computer parses the received data and commands, calculates the control quantities of the helicopter servo and fixed-wing servo, the expected nacelle tilt angle and the expected engine speed through the tilt-rotor flight control algorithm, or receives the control quantities of the helicopter servo and fixed-wing servo, the expected nacelle tilt angle and the expected engine speed from the ground station, and sends them to the FPGA chip through the SPI bus at a frequency of 50HZ. The FPGA chip converts the control quantities into PWM waves to control the helicopter servo and fixed-wing servo, and finally controls the helicopter swashplate and fixed-wing control surface. At the same time, it sends the expected nacelle tilt angle and the expected engine speed to the tilt control system and the information acquisition system respectively through the 485 bus.

[0032] As Figure 3 shown, the tilt control system includes an airborne computer, a tilt angle sensor, a modulation and demodulation chip, and a tilt motor controller. The airborne computer is STM32F103, the tilt angle sensor is a resolver of model TS2620N271, and the modulation and demodulation chip is AD2S1200. The modulation and demodulation chip is connected to the resolver through a signal line to convert the cos / sin signal into an angle signal. The airborne computer communicates with the modulation and demodulation chip through the SPI bus to collect the nacelle tilt angle data of the tilt angle sensor. The airborne computer communicates with the flight control system through the RS485 bus to receive the expected nacelle tilt angle and send the actual nacelle tilt angle. The airborne computer of the tilt machine calculates the rotation speed of the tilt motor through the classical PID control algorithm according to the expected nacelle tilt angle and the actual nacelle tilt angle, and controls the rotation of the tilt motor through RS232.

[0033] As Figure 4As shown, the information acquisition system includes an airborne computer, a nacelle gearbox lubricating oil temperature sensor, a nacelle gearbox lubricating oil pressure sensor, and a throttle servo. The airborne computer is an STM32F103. The airborne computer acquires the data of the nacelle gearbox lubricating oil temperature sensor and the nacelle gearbox lubricating oil pressure sensor through the RS232 interface. The airborne computer acquires the monitoring data of the engine ECU control unit through the RS232 interface. The airborne computer sends the above data to the flight control system through the RS485 bus and receives the desired rotational speed command of the flight control system. The information acquisition airborne computer obtains the control quantity of the throttle servo through the classical PID control algorithm according to the acquired rotational speed data and the desired rotational speed of the engine, converts it into PWM information to control the throttle servo, and keeps the engine rotational speed constant at the set value.

[0034] As Figure 5 shown, it is a schematic diagram of a tandem tiltrotor aircraft, where 1 is a fixed-wing control surface, 2 is a swashplate, 3 is a tilt nacelle, and 4 is a tilt motor.

[0035] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should be regarded as the protection scope of the present invention.

Claims

1. A flight control system for a transverse double tilt-rotor aircraft, characterized in that, it includes: a flight control system installed on the aircraft body, and a tilt control system and an information acquisition system connected to it through a bus; the flight control system includes an FPGA chip and a flight control on-board computer, a sensor group, a digital frequency-hopping radio, a helicopter servo, and a fixed-wing servo connected to it respectively; the flight control system is connected to the ground station through a digital frequency-hopping radio; the FPGA chip reads ground station instructions and sensor data, reads ECU data, gearbox temperature and pressure data collected by the information acquisition system, and reads the actual nacelle tilt angle collected by the tilt control system and sends it to the flight control on-board computer; the flight control on-board computer receives data and instructions, outputs the rotational speed control signal of the helicopter servo and the fixed-wing servo, and outputs the desired nacelle tilt angle signal and the desired engine speed signal; the tilt control system includes a tilt on-board computer and a modulation and demodulation chip and a tilt motor connected to it respectively, and the modulation and demodulation chip is also connected to a tilt angle sensor; the modulation and demodulation chip collects the cos / sin signals of the resolver and converts them into angle signals and sends them to the tilt on-board computer; the tilt on-board computer collects the angle signals and converts them into the actual nacelle tilt angle, and according to the desired nacelle tilt angle, through the PID control algorithm, outputs the rotational speed of the tilt motor to control the rotation of the tilt motor; the information acquisition system includes an information acquisition on-board computer and an engine ECU, a nacelle gearbox lubricating oil temperature sensor, a nacelle gearbox lubricating oil pressure sensor, and a throttle servo connected to it respectively; the throttle servo controls the engine speed of the aircraft, and the on-board computer collects gearbox temperature and pressure data and ECU speed data; according to the desired engine speed, through the PID control algorithm, outputs the rotational speed control amount of the throttle servo, and converts it into a PWM signal to control the throttle servo to keep the engine speed constant at the set value.

2. The flight control system for a transverse double tilt-rotor aircraft according to claim 1, characterized in that, the flight control system, the tilt control system, and the information acquisition system communicate through a 485 bus.

3. The flight control system for a transverse double tilt-rotor aircraft according to claim 1, characterized in that, the sensor group includes a differential pressure sensor + pitot tube module, an inertial measurement unit, a barometric pressure sensor, a satellite positioning module, and a magnetic compass, which respectively collect airspeed data, three-axis acceleration and angle data, barometric altitude data, real-time position data, and heading data.

4. The flight control system for a transverse double tilt-rotor aircraft according to claim 3, characterized in that, the FPGA chip is connected to the barometric pressure sensor, the satellite positioning module, the magnetic compass, and the digital frequency-hopping radio through an RS232 interface; connected to the differential pressure sensor + pitot tube module, the inertial measurement unit, the barometric pressure sensor, and the flight control on-board computer through an SPI bus, and connected to the helicopter servo and the fixed-wing servo through a PWM port.

5. The flight control system for a transverse double tilt-rotor aircraft according to claim 4, characterized in that, The helicopter servo is connected to the helicopter swashplate, and the fixed-wing servo is connected to the fixed-wing control surface. The PWM port outputs a PWM signal to control the helicopter swashplate and the fixed-wing control surface.

6. A flight control system for a tandem tiltrotor aircraft according to claim 1, characterized in that the tilt angle sensor is a resolver and is installed on the nacelle rotating shaft.

7. A flight control system for a tandem tiltrotor aircraft according to claim 1, characterized in that the lubricating oil temperature sensor and the lubricating oil pressure sensor are arranged in the nacelle gearbox.

8. A flight control system for a tandem tiltrotor aircraft according to claim 1, characterized in that the tilt airborne computer is connected to the tilt motor through an RS232 interface, connected to the modulation and demodulation chip through an SPI bus, and the modulation and demodulation chip is connected to the tilt angle sensor through a signal line.

9. A flight control system for a tandem tiltrotor aircraft according to claim 1, characterized in that the information acquisition tilt computer is connected to the engine ECU through an RS232 interface, connected to the lubricating oil temperature sensor of the gearbox and the lubricating oil pressure sensor of the nacelle gearbox through an RS232 interface, and connected to the throttle servo through a PWM port.

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