Structural design and control method of a tandem twin-rotor large-angle tiltrotor helicopter

Abstract

This invention discloses a structural design and control method for a tandem twin-rotor tiltrotor helicopter, belonging to the technical field of tiltrotor aircraft. This invention aims to solve the technical problems of limited flight speed in existing tandem helicopters, insufficient tilt angle in traditional tiltrotor models, inability to fly under the fuselage, and difficulty in balancing high payload and high maneuverability. This invention adopts a tandem twin-rotor layout with fixed wings on both sides. Through optimized design of the screw-link tilt drive mechanism, it achieves large-angle, dead-zone-free rotor tilt, enabling special attitude flight under the fuselage. A multi-mode adaptive control method is also designed to achieve seamless switching between helicopter hovering mode, transition mode, and fixed-wing high-speed level flight mode. Simultaneously, it incorporates a full-dimensional status monitoring and safety protection system. This invention effectively retains the advantages of tandem helicopters in terms of high payload and high stability, significantly improving the aircraft's flight speed, low-altitude maneuverability, and adaptability to complex scenarios. With reliable structure and precise control, it can be widely applied in various operational scenarios such as material transportation, emergency rescue, and low-altitude inspection, possessing extremely high practical value and application prospects.

Description

Technical Field

[0001] This invention belongs to the technical field of tiltrotor aircraft, specifically relating to the structural design and control method of a tandem twin-rotor tiltrotor helicopter with a large angle of inclination. It is applicable to various scenarios such as vertical take-off and landing, hovering, high-speed level flight, low-altitude narrow space maneuvering, and flight under the fuselage, and belongs to the field of helicopter structure and flight control technology improvement. Background Technology

[0002] Tandem rotor helicopters, with their symmetrical dual-rotor load-bearing structure, offer advantages such as large payload capacity, uniform load distribution, and good hovering stability, making them widely used in cargo transport, equipment hoisting, and emergency rescue. However, existing conventional tandem rotor helicopters all use a fixed rotor configuration, limiting the range of rotor disk tilt adjustment. They can only achieve attitude adjustment through differences in rotor speed, resulting in limitations such as limited level flight speed, high energy consumption at high speeds, and poor maneuverability.

[0003] Most existing tiltrotor aircraft have a side-by-side layout. A few tandem tiltrotor models suffer from unreasonable layout and limited rotor tilt angles, making it impossible to achieve a flight mode where the rotors face downwards towards the fuselage. This makes them unsuitable for complex operating conditions such as low-altitude obstacle avoidance, narrow airspace maneuvering, and special attitude flight. Furthermore, existing tiltrotor structures are prone to component interference, poor positioning accuracy, and lag in dynamic response. They cannot simultaneously combine the high payload advantages of tandem helicopters with the high-speed, high-maneuverability characteristics of tiltrotor aircraft, resulting in poor adaptability to various scenarios and difficulty in meeting the flight operation requirements of modern complex environments.

[0004] To address the shortcomings of the existing technologies, there is an urgent need to develop a tandem twin-rotor tilt-rotor helicopter structure and corresponding control methods that can achieve large-angle rotor tilting, balance large payload and high maneuverability, and seamlessly switch between multiple flight modes. Summary of the Invention

[0005] Purpose of the invention The purpose of this invention is to overcome the shortcomings of existing technologies and provide a structural design and control method for a tandem twin-rotor large-angle tilting helicopter. It retains the core advantages of traditional tandem twin-rotor helicopters, such as large payload and high stability, while achieving large-angle rotor tilting. It also features an innovative under-fuselage flight mode that can adaptively switch between helicopter hovering mode, transitional flight mode, and fixed-wing high-speed level flight mode. This effectively improves the aircraft's flight speed, maneuverability, and adaptability to complex scenarios, solving the technical problems of limited speed, insufficient tilt angle, weak maneuverability, and limited adaptability to operating conditions in traditional models. Technical solution

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A tandem twin-rotor tilt-rotor helicopter structure includes a fuselage, a fixed wing assembly, a front and rear twin-rotor power system, a tilt-drive mechanism, retractable landing gear, auxiliary function systems, and a flight control system. The front and rear twin-rotor power systems are arranged tandemly on the front and rear top of the fuselage, the fixed wing assembly is symmetrically arranged on the left and right sides of the fuselage, the tilt-drive mechanism is installed corresponding to and matched with the front and rear twin-rotor power systems, the retractable landing gear is mounted on the bottom of the fuselage, and the auxiliary function systems and flight control system are built into the fuselage.

[0008] The fuselage adopts a longitudinally arranged rectangular streamlined configuration, with an integrated enclosed payload bay in the middle of the fuselage for carrying operational loads; a V-tail is provided at the rear of the fuselage for level flight directional stability and attitude correction; the fuselage interior has reserved equipment installation cavities and high-strength support bases to provide installation support and structural protection for various functional components.

[0009] The fixed wing assembly is a symmetrical fixed wing with a streamlined aerodynamic design. High-strength reinforcing ribs are embedded inside the wing to enhance the overall structural load-bearing capacity. Spoilers and flaps electrically connected to the flight control system are installed on the trailing edge of the wing, which can adaptively adjust the wing surface angle according to the flight status. At the same time, the overall wing layout avoids the rotor tilt trajectory and is adapted to the large-angle tilt motion of the propeller, completely eliminating component interference problems.

[0010] The front and rear twin propeller power system has a symmetrical structure, each including a drive engine, a hub, and multiple variable-pitch blades. The blades are made of lightweight, high-strength composite materials and have the characteristics of resistance to deformation, high speed, and large-angle variable-pitch adaptability. The front propeller always maintains a positive thrust output state, while the rear propeller can adaptively switch between three power output states: thrust, horizontal thrust, and downward lift, depending on the flight mode.

[0011] The tilt drive mechanism consists of two identical sets, one at the front and one at the rear. Each set comprises a servo motor, a lead screw, a sliding block, a hinged link, and a positioning nut. The servo motor serves as the power source, driving the rotor to tilt as a whole through the lead screw and slider transmission in conjunction with the link mechanism. The positioning nut is used for locking and positioning to ensure the accuracy of the tilt angle. The propeller can achieve a vertically upward initial position to a vertically downward position and a large lateral tilt angle, enabling flight operations below the fuselage.

[0012] The auxiliary function system includes a built-in fuel tank, a hydraulic drive system, and a cooling system. The hydraulic drive system provides power support for large-angle rotor tilting, landing gear retraction and extension, and wing surface adjustment. The cooling system provides real-time cooling for the engine, servo motor, and control module to ensure stable operation of the equipment over a long period of time. A protective cover can be detachably installed on the outside of the propeller to prevent foreign objects from being entrained or components from colliding and interfering during flight.

[0013] The flight control system integrates a hybrid control algorithm module, a flight status monitoring module, a fault diagnosis module, and a manual intervention module. It can collect flight parameters in real time, precisely adjust the rotor tilt angle, and adaptively switch flight modes. It also has automatic fault alarm, emergency attitude correction, and manual precise control functions to ensure flight safety.

[0014] A control method for a tandem twin-rotor large-angle tilt helicopter, based on the aforementioned tandem twin-rotor large-angle tilt helicopter structure, includes three core steps: real-time flight status monitoring, multi-flight mode adaptive switching control, and all-time safety protection control, as detailed below:

[0015] (1) Real-time monitoring of flight status: Through attitude sensors, distance sensors, force sensors and airflow monitoring sensors mounted on the fuselage, the core parameters such as the flight attitude, rotor tilt angle, structural stress, airflow disturbance and fuselage ground distance are collected in real time and transmitted to the flight control system. The control system dynamically corrects the control parameters, predicts the risk of component interference, and realizes active protection.

[0016] (2) Multi-flight mode adaptive switching control:

[0017] ① Helicopter hovering mode: Control the front and rear rotors to maintain an initial vertical upward state. The rotor rotation generates vertical lift to counteract the weight of the fuselage, achieving vertical take-off and landing and hovering at a fixed point. By dynamically adjusting the difference in rotational speed between the front and rear rotors and the blade pitch, pitch, roll, and yaw attitude fine-tuning can be completed. In the hovering state, the rotor tilt angle can be slightly corrected to counteract airflow disturbances and ensure hovering stability.

[0018] ② Transitional Flight Mode: According to flight commands, the control system controls the tilt drive mechanism to tilt the front and rear propellers forward and backward at large angles respectively; synchronously linking the wing spoilers and flaps to adjust the aerodynamic angle of the wing surface, dynamically matching the rotor power output, and realizing a seamless transition between helicopter mode and fixed-wing mode, avoiding sudden attitude changes and power interruptions.

[0019] ③ Fixed-wing high-speed level flight and downward flight mode: In normal high-speed level flight, the front and rear propellers are kept horizontally arranged, the fixed wings provide the main aerodynamic lift, and the rotors output horizontal thrust to achieve high-speed cruise; when facing special conditions such as low-altitude obstacles and narrow spaces, the rotors are controlled to tilt downward to the fuselage, and the downward power output of the rear rotor is combined with the thrust of the front rotor to achieve special flight maneuvers such as flying under the fuselage, ground-hugging maneuvers, and attitude avoidance, which greatly improves flight maneuverability.

[0020] (3) All-time safety protection and control: During flight, the fault diagnosis module monitors the operating status of the power system, tilt mechanism and control system in real time. When abnormality of components, power failure or attitude deviation is detected, the system automatically triggers audible and visual alarms and performs emergency attitude correction and power redundancy control operations. The system has a reserved manual control interface, which can manually intervene to adjust the rotor tilt angle and power output. The distance sensor at the bottom of the fuselage monitors the ground clearance and distance to obstacles in real time, effectively avoiding the risk of low-altitude collision. Beneficial effects

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. This invention retains the core advantages of tandem twin-rotor helicopters, such as large payload, uniform load distribution, and high hovering stability. At the same time, by optimizing the tilt drive structure, it achieves large-angle rotor tilting, breaking through the large-angle tilting limit of traditional tilt rotor models. It also pioneers a flight mode under the fuselage, which can adapt to maneuvering flight in low-altitude narrow spaces and complex obstacle environments, making it highly adaptable to various scenarios.

[0023] 2. This invention features a fixed wing with an adaptively adjustable wing structure, combined with multi-mode power switching control, enabling seamless switching between multiple modes such as vertical hovering, transitional flight, and high-speed level flight. This solves the problems of slow flight speed and high energy consumption of traditional tandem helicopters, significantly improving flight efficiency and cruise speed.

[0024] 3. This invention employs a high-precision ball screw tilting mechanism, coupled with a hybrid control algorithm, resulting in high tilting positioning accuracy and fast dynamic response speed, effectively avoiding structural interference between the rotor and the fuselage and wings; it is also equipped with a full-dimensional condition monitoring and fault emergency system, providing dual protection for flight stability and safety.

[0025] 4. The present invention has a reasonable structural layout, high integration and strong reliability, and takes into account both load-bearing performance and mobility performance. It can be widely used in scenarios such as material transportation, emergency rescue, low-altitude inspection and special environment operation, and has extremely high practicality and promotion value. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of a tandem twin-rotor tiltrotor helicopter.

[0027] Figure 2 These are diagrams illustrating the three flight modes;

[0028] Explanation of reference numerals in the attached diagram: 1 Front propeller assembly, 2 Rear propeller assembly, 3 Rotation axis, 4 Fixed wing, 5 Fuselage, 6 Overhead flight mode, 7 Level flight mode, 8 Downward flight mode. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to specific embodiments.

[0030] The present invention discloses a tandem twin-rotor tilt-rotor helicopter with a large angle of rotation. The overall layout is a tandem twin-rotor helicopter with fixed wings on both sides. The fuselage is made of lightweight high-strength alloy material. The central payload bay can be adapted to different operational loads according to requirements. The bottom retractable landing gear extends during takeoff and landing and retracts during level flight, effectively reducing flight drag.

[0031] In conventional takeoff, landing, and hovering scenarios, the aircraft switches to helicopter mode, the tilt drive mechanism locks the rotor in a vertically upward state, and the front and rear rotors rotate synchronously to generate vertical lift. By adjusting the speed of the front and rear rotors and the blade pitch, the aircraft's ascent, descent, translation, and hovering attitude are precisely controlled. In conjunction with the V-tail, the heading is corrected, achieving stable hovering and vertical takeoff and landing.

[0032] In high-speed cruise operation scenarios, the aircraft enters a transition mode. The servo motor drives the lead screw and slider to move, which in turn drives the front and rear rotors to tilt forward and backward through the linkage mechanism. Simultaneously, the opening angle of the wing flaps and spoilers is adjusted, and the power output mode is gradually switched from rotor lift to wing aerodynamic lift. Finally, the rotors maintain a horizontal state and output horizontal thrust to achieve high-speed fixed-wing level flight, which greatly improves flight speed and reduces flight energy consumption.

[0033] In complex and confined space operations at low altitudes, the rotor can tilt and rotate to a position under the fuselage via a tilt drive mechanism. The rear rotor outputs downward force while the front rotor maintains positive thrust. Combined with obstacle monitoring data from fuselage sensors, it enables ground-hugging flight, obstacle avoidance, and precise close-range operations, solving the problem that traditional aircraft cannot perform negative-angle and under-fuselage maneuvering.

[0034] Throughout the flight, the control system collects various sensor data in real time, dynamically corrects the tilt angle, power output, and wing attitude. When equipment failure, attitude deviation, or collision risk is detected, the emergency protection mechanism is automatically activated. Manual intervention is also supported, ensuring flight operation safety in all aspects.

Claims

1. A control method for a tandem twin-rotor large-angle tilt helicopter, characterized in that: The system includes a fuselage, fixed wing assembly, front and rear twin propeller propulsion systems, tilt-drive mechanism, retractable landing gear, auxiliary function systems, and flight control system. The front and rear twin propeller propulsion systems are arranged longitudinally on the top front and rear of the fuselage. The fixed wing assembly is symmetrically arranged on the left and right sides of the fuselage. The tilt-drive mechanism is installed correspondingly to the front and rear twin propeller propulsion systems. The retractable landing gear is mounted on the bottom of the fuselage. The auxiliary function systems and flight control system are built into the fuselage. The front and rear twin propeller propulsion systems include a front propeller and a rear propeller. The front propeller always outputs forward thrust, while the rear propeller can switch between three power modes: thrust, pull, and downward lift. The tilt-drive mechanism can drive the propellers to complete large-angle, dead-zone-free tilting, enabling flight attitude operations under the fuselage.

2. The tandem twin-rotor large-angle tilting helicopter structure according to claim 1, characterized in that: The fuselage adopts a longitudinally arranged rectangular streamlined configuration, with a closed payload compartment in the middle of the fuselage, a V-shaped tail fin at the rear of the fuselage, and reserved equipment installation cavities and high-strength support bases inside the fuselage.

3. The tandem twin-rotor large-angle tilting helicopter structure according to claim 1, characterized in that: The fixed wing assembly is a symmetrical streamlined wing with pre-embedded reinforcing ribs inside. The trailing edge of the wing is fitted with spoilers and flaps that are electrically connected to the flight control system. The wing layout avoids the rotor tilt trajectory and is adapted to the large-angle tilt motion of the propeller.

4. The tandem twin-rotor large-angle tilting helicopter structure according to claim 1, characterized in that: Both the front and rear twin propeller power systems include a drive engine, a propeller hub, and multiple variable-pitch blades, the blades of which are made of lightweight, high-strength composite materials.

5. The tandem twin-rotor large-angle tilting helicopter structure according to claim 1, characterized in that: The tilt drive mechanism is set in two sets with identical structures. Each set of tilt drive mechanism consists of a servo motor, a transmission screw, a sliding block, a hinged connecting rod and a positioning nut. The positioning nut is used to lock and position the tilt angle.

6. The tandem twin-rotor large-angle tilting helicopter structure according to claim 1, characterized in that: The propeller has a vertically upward initial zero position, which can achieve large-angle tilting without dead zones and can stably maintain the tilting working state under the fuselage.

7. The tandem twin-rotor large-angle tilting helicopter structure according to claim 1, characterized in that: The auxiliary function system includes a built-in fuel tank, a hydraulic drive system, and a cooling system. A protective cover can be detachably installed on the outside of the propeller. The hydraulic drive system provides power for rotor tilting, landing gear retraction and extension, and wing surface adjustment. The cooling system dissipates heat from the airborne equipment.

8. The tandem twin-rotor large-angle tilting helicopter structure according to claim 1, characterized in that: The flight control system integrates a hybrid control algorithm module, a flight status monitoring module, a fault diagnosis module, and a manual intervention module, which are used to precisely control the rotor tilt angle, adaptively switch flight modes, provide fault alarms, and provide emergency protection.

9. A control method for a tandem twin-rotor helicopter with a large-angle tilt, characterized in that: The tandem twin-rotor large-angle tilt helicopter structure described in any one of claims 1-8 includes real-time flight status monitoring, multi-flight mode adaptive switching control, and all-time safety protection control; through the coordinated regulation of various components by the flight control system, large-angle tilting of the propellers and seamless switching of multiple flight modes are achieved, with the front propeller continuously outputting positive thrust and the rear propeller adaptively switching power output states.

10. A control method for a tandem twin-rotor large-angle tilt helicopter according to claim 9, characterized in that: The real-time flight status monitoring specifically involves: using attitude sensors, distance sensors, force sensors, and airflow monitoring sensors mounted on the fuselage to collect parameters such as aircraft attitude, rotor tilt angle, structural stress, airflow disturbance, and ground clearance in real time, dynamically correcting control parameters, and predicting structural interference risks.

11. A control method for a tandem twin-rotor large-angle tilt helicopter according to claim 9, characterized in that: The multi-flight mode adaptive switching control includes helicopter hovering mode, transitional flight mode, fixed-wing high-speed level flight and downward flight mode; in the helicopter hovering mode, the propeller remains vertically upward, and the flight attitude is controlled by adjusting the rotor speed difference and blade pitch. When hovering, the rotor tilt angle is finely adjusted to counteract airflow disturbances.

12. The control method for a tandem twin-rotor large-angle tilt helicopter according to claim 11, characterized in that: In the transitional flight mode, the front and rear propellers tilt forward and backward at large angles respectively, synchronously adjusting the rotor power output and the aerodynamic angles of the wing spoilers and flaps to achieve seamless transition between flight modes.

13. The control method for a tandem twin-rotor large-angle tilt helicopter according to claim 11, characterized in that: In the fixed-wing high-speed level flight and downward flight modes, the propeller is horizontally arranged in normal level flight, and the fixed wing provides the main lift; under special conditions, the propeller tilts at a large angle to the underside of the fuselage to achieve low-altitude maneuvering flight under the fuselage.

14. A control method for a tandem twin-rotor large-angle tilt helicopter according to claim 9, characterized in that: The all-weather safety protection and control system includes real-time equipment status monitoring, automatic fault alarm, emergency attitude correction, and manual intervention control; a distance sensor is installed on the bottom of the fuselage to monitor obstacles and ground clearance in real time to prevent low-altitude collisions.

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