A vertical take-off and landing-fixed wing aircraft and its modes of operation and method

Abstract

The present application belongs to the technical field of aircraft control, and particularly relates to a vertical take-off and landing-fixed wing aircraft and a control mode and method thereof. The change of a vertical position is controlled by a longitudinal control of a driving rod, the change of a lateral position is controlled by a transverse control of the driving rod, the change of a forward position is controlled by a control of a throttle table, and the change of a heading is controlled by a control of a footrest. The control mode of the control mechanism is unified, consistent control perception is realized, and repeated training, understanding difference and flight safety caused by different control perceptions are avoided.

Description

Technical Field

[0001] This invention belongs to the field of aircraft control technology, and particularly relates to a vertical take-off and landing (VTOL) fixed-wing aircraft and its control mode and method. It is applicable to the control technology of manned aircraft during take-off, landing and cruise in limited fields and airspaces. Specifically, it provides the control stick operation response logic design strategy and the correspondence with the generalized operation surface response characteristics in both rotor / VTOL and fixed-wing modes. Background Technology

[0002] In traditional flight control, fixed-wing manned aircraft use control devices such as a control stick, pedals, and throttle. Takeoff is achieved by gaining lift through a long ground run, and landing is completed following a designed long flight path or five-sided approach. During this process, the control stick typically generates pitch rate or overload commands to control longitudinal position, the control stick typically generates roll rate commands to control roll flight, the pedals correspond to yaw rate commands to adjust the nose heading, and the throttle corresponds to throttle opening commands to control speed. While there is some coupling between these controls throughout the flight, the above correspondence is generally maintained. In rotor mode, flight status is controlled via the collective pitch stick, cyclic stick, and pedals. Takeoff and landing can be achieved in limited spaces. The collective pitch stick typically controls the main propeller blade tilt angle to adjust the longitudinal thrust of the fuselage shaft, thus changing the longitudinal position. The cyclic stick controls the main propeller blade angle of attack in different directions to adjust the horizontal force distribution, thus achieving left, right, forward, and backward movement. The pedals control the output power of the tail rotor and the influence of blade tilt adjustment on the horizontal direction of the rotorcraft.

[0003] In summary, fixed-wing and rotary-wing aircraft exhibit significant differences in operational perception for similar maneuvers. Operating different modes on the same aircraft type requires extensive and time-consuming training. Furthermore, existing fixed-wing flight presents numerous challenges, including stringent requirements for airport environments and facilities, such as the inability to perform routine takeoffs and landings on limited decks or crowded urban rooftops. Simultaneously, regarding flight control itself, the coupling between control axis and response characteristics necessitates lengthy training to familiarize oneself with these characteristics, resulting in differences in piloting habits between different aircraft types. Summary of the Invention

[0004] The purpose of this invention is to provide a vertical takeoff and landing (VTOL) fixed-wing aircraft and its control mode and method to improve the consistent perception of the same control response throughout the flight process.

[0005] To achieve the above objectives, the present invention employs the following technical solution.

[0006] In a first aspect, the present invention provides a vertical takeoff and landing fixed-wing aircraft, comprising at least: a lift fan and a main engine;

[0007] The lift fan generates the pitching moment and the required yaw moment by adjusting the throttle opening and its own longitudinal and lateral yaw angles;

[0008] The main engine is equipped with a three-bearing vector nozzle at the tail. The three-bearing vector nozzle can deflect at any angle in the longitudinal and lateral directions to provide thrust or lift to the airframe, as well as the yaw torque required for the airframe to deflect.

[0009] Roll nozzles are installed on both sides of the wing. By extracting the flow rate from the main duct, a downward airflow is generated, and the deviation of the flow rate of the roll nozzle is controlled to adjust the roll attitude of the aircraft.

[0010] Secondly, the present invention provides a unified vertical takeoff and landing (VTOL)-fixed-wing control mode, wherein the control mode is applied to the aircraft described in the first aspect, and the mode is as follows:

[0011] Longitudinal control of the control stick corresponds to changes in vertical position, lateral control corresponds to changes in lateral position, throttle control corresponds to changes in forward position, and pedal control corresponds to changes in heading.

[0012] Furthermore, the throttle control corresponds to changes in the forward position, including acceleration control and forward speed control, specifically implemented as follows:

[0013] In forward speed control mode:

[0014] PLA_forvel(t)=PLA0_forvel+K_P_forvel*(Vb_x_ref(t)-Vb_x(t))+K_I_forvel* ∫(Vb_x_ref(t)-Vb_x(t))dt+K_P_H*(H_ref(t)-H(t))+K_I_H*∫(H_ref(t)-H(t))dt

[0015] PLA_y_angle(t)=Angle0+K_P_y_angle*(Vb_x_ref(t)-Vb_x(t))+K_I_y_angle*∫(Vb_x_ref(t)-Vb_x(t))dt

[0016] Wherein, Vb_x_ref(t) is the forward speed command, Vb_x(t) is the forward speed feedback, H_ref(t) is the altitude command, and H(t) is the altitude feedback. The throttle opening component PLA_forvel(t) and the nozzle longitudinal deflection angle PLA_y_angle(t) are given simultaneously through proportional-integral calculation. K_P_forvel, K_I_forvel, K_P_H, K_I_H, K_P_y_angle and K_I_y_angle are the corresponding PI parameters. Angle0 is the initial preset value of the nozzle longitudinal deflection angle. The preset value is 0° when transitioning from hovering to cruising and 90° when transitioning from cruising to hovering. PLA0_forvel is the throttle preset value.

[0017] In acceleration control mode, acceleration commands and acceleration feedback are used to achieve forward acceleration closed loop through throttle opening and tail nozzle longitudinal deflection angle.

[0018] Furthermore, the longitudinal control of the control stick corresponds to changes in the vertical position, including: vertical speed control and angular rate / overload control;

[0019] Vertical speed control in vertical takeoff and landing mode provides the required lift by adjusting the thrust of the main engine, while the lift fan stabilizes the pitch attitude based on the pitch moment balance.

[0020] PLA_vz(t)=PLA0_vz+K_P_vz*(V_z_ref(t)-V_z(t))+K_I_vz*∫(V_z_ref(t)-V_z(t))dt

[0021] Where V_z_ref(t) is the vertical velocity command corresponding to the longitudinal rod displacement, V_z(t) is the vertical velocity feedback, PLA_vz(t) is the required throttle opening, K_P_vz and K_I_vz are the corresponding control parameters, and PLA0_vz is the throttle preset value;

[0022] In fixed-wing mode, angular rate / overload control is enhanced through feedback of angular rate, angle of attack, and overload to improve control and stability. Based on this, at low speeds, the pitch control command corresponds to the angular rate command, and the elevator command is generated through the angular rate closed loop. At high speeds, the pitch control command corresponds to the overload command, and the elevator command is generated through the overload closed loop, which ultimately drives the control surfaces to deflect and change the flight state of the aircraft.

[0023] Furthermore, the changes in lateral position corresponding to the lateral control of the control stick include: control stick horizontal bar-lateral speed control and control stick vertical bar-roll rate control;

[0024] In vertical takeoff and landing mode, the horizontal bar corresponds to the lateral speed command, which realizes the translation of the lateral position, drives the deflection angle of the lift fan and the main engine to provide lateral force, and the rolling nozzle needs to balance the rolling attitude during the process.

[0025] PLA_z_angle(t)=K_P_z_angle*(Vb_y_ref(t)-Vb_y(t))+K_I_z_angle*∫(Vb_y_ref(t)-Vb_y(t))dt

[0026] Where Vb_y_ref(t) is the lateral velocity command corresponding to the crossbar travel, Vb_y(t) is the actual lateral velocity feedback, PLA_z_angle(t) is the lateral deflection angle of the main engine exhaust nozzle, and K_P_z_angle and K_I_z_angle are the corresponding control parameters;

[0027] Lateral deflection generates lateral force and yaw moment. The lift fan needs to deflect accordingly to counteract the yaw moment generated by the main engine exhaust nozzle, thereby achieving lateral position translation.

[0028] In fixed-wing mode, roll characteristics are improved through angular rate and sideslip angle feedback. Based on this, the stick command generates the corresponding roll angular rate command to achieve closed-loop control of the roll angular rate, and outputs to drive the ailerons to change the flight state of the aircraft.

[0029] Furthermore, the pedal control corresponds to changes in heading, specifically as follows:

[0030] Regardless of whether it is rotor / vertical takeoff and landing mode or fixed-wing mode, the foot pedals correspond to the yaw rate command.

[0031] In fixed-wing mode, the flight state is changed by driving the rudder through a closed-loop yaw rate drive.

[0032] In vertical takeoff and landing mode, yaw moment is generated by changing the deflection angle of the lift fan and the main engine exhaust nozzle, thereby achieving on-the-spot heading adjustment. During this process, the roll nozzle is required to maintain the roll attitude.

[0033] Thirdly, the present invention provides a unified vertical takeoff and landing (VTOL)-fixed-wing control method, implemented using the control mode described in the second aspect. In manual flight mode, the method includes:

[0034] Step 1: With the ground stationary, power on the equipment and start all engines. At this time, the tail nozzle is at 90°, the roll nozzle and lift fan are turned on, the control surface deflection is at the preset value, and the control stick, throttle, and pedals are all at zero.

[0035] Step 2: Pull the control stick back. This generates an upward vertical speed command. The required throttle opening is generated based on the vertical speed control of the control stick. The full authority digital engine control system (FADEC) drives the engine to generate the corresponding thrust, and the aircraft changes its upward motion. During this process, in order to maintain the balance of pitch attitude, the lift fan needs to generate a corresponding force to balance the pitch moment.

[0036] Step 3: Adjust the heading during flight. If a left yaw is required, depress the left rudder pedal. According to the pedal-yaw rate control, the tail nozzle deflects to the left and the lift fan deflects to the right, generating a negative yaw moment, which in turn causes the nose to yaw to the left. If a right yaw is required, depress the right rudder pedal. According to the pedal-yaw rate control, the tail nozzle deflects to the right and the lift fan deflects to the left, generating a positive yaw moment, which in turn causes the nose to yaw to the right. During this process, the roll nozzle needs to be used in conjunction to maintain the roll attitude.

[0037] Step 4: Lateral translation during flight. If leftward translation is required, push the control stick to the left. According to the control stick horizontal stick-lateral speed control, the tail nozzle deflects to the right, and the lift fan also deflects to the right to counteract the yaw moment. The combined effect generates a lateral force to the left, causing the aircraft to translate to the left. If rightward translation is required, push the control stick to the right. According to the control stick horizontal stick-lateral speed control, the tail nozzle deflects to the left, and the lift fan also deflects to the left to counteract the yaw moment. The combined effect generates a lateral force to the right, causing the aircraft to translate to the right.

[0038] Step 5: After the aircraft ascends to a certain stage, it remains in a hovering state. At this time, all operating devices return to zero. Then, push the throttle forward to generate forward acceleration. This process achieves altitude hold flight. According to the throttle-acceleration control / forward speed control, the corresponding throttle opening command and tail nozzle longitudinal deflection angle are generated. Since the control stick and pedals are not deflected, the corresponding command is zero. According to the control stick longitudinal stick-angular rate / overload control, control stick transverse stick-roll angular rate control, and pedals-yaw angular rate control, the attitude is stabilized by controlling the control surfaces.

[0039] Step 6: When the speed reaches a certain value, the deflection angle of the tail nozzle will approach 0°. Switch from vertical take-off and landing mode to fixed-wing mode by pressing the toggle switch. The tail nozzle will transition to 0°, and the lift fan and roll nozzle will be turned off. At this time, control of the fixed-wing aircraft can be achieved by operating the control stick, throttle, and pedals according to the throttle-acceleration control / forward speed control, control stick vertical stick-angular rate / overload control, control stick horizontal stick-roll angular rate control, and pedal-yaw angular rate control.

[0040] Step 7: To switch from fixed-wing mode to vertical takeoff and landing mode, you first need to decelerate. After reaching the transition corridor, switch to vertical takeoff and landing mode via the button. At this time, the throttle stick is at the maximum deflection position, and the control stick and pedals are at zero. During this process, reduce the throttle stick to achieve constant altitude deceleration flight. The throttle opening and tail nozzle longitudinal deflection angle are controlled by throttle-acceleration control / forward speed control. Due to the high speed, the attitude is stabilized by controlling the control surfaces by controlling the control stick longitudinal stick-angular rate / overload control, control stick lateral stick-roll angular rate control, and pedal-yaw angular rate control.

[0041] Step 8: Gradually reduce the throttle to zero. At this point, the aircraft should be hovering. Then, adjust the aircraft's heading by pressing the pedals according to the yaw rate control, and adjust the aircraft's lateral position by pressing the left control stick according to the stick control.

[0042] Step 9: Pull back the control stick to generate downward vertical acceleration. Adjust the throttle opening of the main engine according to the vertical speed control of the control stick. The lift fan works in conjunction to maintain the longitudinal attitude, gradually reduce the flight altitude, and then achieve landing.

[0043] Furthermore, in automatic flight mode, the method includes:

[0044] Step 1: Ground status, power on the equipment, start the engine, and enter the ground waiting phase. Click takeoff, set the hovering altitude, calculate the vertical rate based on the hovering altitude, and generate the throttle opening command in combination with the control stick pitch control. The lift fan adjusts the opening to maintain the pitch attitude.

[0045] Step 2: During flight, maintain a stable heading and zero roll attitude. To control heading stability, a yaw rate command is generated based on the deviation from the current heading. The tail nozzle and lift fan are deflected accordingly based on the pedal-yaw rate control to adjust the heading. The roll attitude is zeroed through differential control of the roll nozzle.

[0046] Step 3: Enter the hovering phase. Given a forward acceleration command, and combined with the current hovering height, the main engine throttle opening command and the longitudinal deflection angle command of the tail nozzle are obtained according to the throttle-acceleration control / forward speed control. This enables control of the corresponding equipment and generates forward thrust. During this process, pitch attitude command, roll attitude command, and heading command need to be given. Through corresponding status feedback, the corresponding control surfaces are controlled in combination with the control stick pitch-angular rate / overload control, control stick yaw rate control, and pedal-yaw rate control.

[0047] Step 4: When the speed reaches a certain value, it automatically switches to fixed-wing mode and flies along the route based on throttle-acceleration control / forward speed control, control stick pitch control-angular rate / overload control, control stick yaw rate control and pedal control-yaw rate control.

[0048] Step 5: When switching from fixed-wing mode to vertical takeoff and landing mode, automatic switching is achieved when deceleration reaches a certain stage. Based on the current altitude and forward acceleration command, the main engine throttle opening and tail nozzle longitudinal deflection angle are controlled in combination with throttle-acceleration control / forward speed control to decelerate to a hovering state.

[0049] Step 6: When the hovering point does not match the desired position, the position and heading are adjusted by combining forward deviation, lateral deviation, and heading deviation with throttle-acceleration control / forward speed control, control stick-lateral speed control, and pedal-yaw rate control.

[0050] Step 7: In the hovering state, the given height command is zero. Combined with the control stick longitudinal stick-vertical speed control, the throttle opening of the main engine and lift fan is controlled, thereby achieving a smooth ground contact.

[0051] The technical solution of this invention provides a complete method for solving vertical takeoff and landing flight control, which can quickly adapt to the flying habits of vertical takeoff and landing mode and fixed-wing mode without causing differences in control perception, reduce the economic and time costs of pilot training, improve the control technology of aircraft, and promote the application and popularization of manned / unmanned aircraft in limited sites and airspaces. Detailed Implementation

[0052] This invention provides a unified control method for fixed-wing, rotary-wing, and civilian eVTOL (electric vertical takeoff and landing) aircraft during takeoff, landing, and cruise in limited spaces and airspaces. This achieves consistent control perception, thereby avoiding repetitive training, misunderstandings, and even flight safety issues caused by different control perceptions. It can provide more convenient flight control methods for aircraft in both military and civilian fields in the future, enrich the application scenarios of aircraft, popularize market demand for aircraft use, and lower the barrier to entry.

[0053] In order to maintain consistent control response and control perception across different flight modes, a unified control mode requires the cooperation of corresponding control devices, including the use of the stick and active throttle. Programmable stick-force characteristics enable more refined and accurate control perception in different modes.

[0054] Briefly introduce the aircraft object, including the wing surfaces and power configuration of the short vertical / vertical landing gear.

[0055] The following section mainly introduces the technical details of vertical takeoff and landing flight control with vectoring nozzles. First, the structure of the aircraft equipped with vectoring nozzles and its operating surfaces are explained:

[0056] The aircraft studied includes a propulsion system comprising a lift fan and a main engine. The lift fan features adjustable throttle opening and longitudinal and lateral deflection angles, primarily generating pitching moment and the required yaw moment. A three-bearing vectoring nozzle is mounted at the tail of the main engine, allowing for arbitrary longitudinal and lateral deflection, mainly providing thrust or lift and the necessary yaw moment. Roll nozzles are installed on both sides of the wings, generating downward airflow by extracting airflow from the main engine duct, enabling flow deviation control to adjust roll attitude. Furthermore, in fixed-wing mode, it features conventional elevators, ailerons, and rudders.

[0057] This invention provides a vertical takeoff and landing (VTOL) fixed-wing aircraft and its control modes and methods; the control modes are described in detail below:

[0058] 1. Unified Control Mode:

[0059] Given the differences in control methods between traditional rotor / vertical takeoff and landing and fixed-wing modes, in order to avoid flight safety issues caused by inconsistent control characteristics due to mode misjudgment, the pilot's perception of the control stick, pedals, and throttle should remain consistent at all times.

[0060] From a top-level design perspective, longitudinal control of the control stick corresponds to changes in vertical position, lateral control of the control stick corresponds to changes in lateral position, throttle control corresponds to changes in forward position, and pedal control corresponds to changes in heading. This is the most basic idea behind the unified operating mode.

[0061] In different modes, the controlled objects of each control axis differ, but the control response must conform to the aforementioned characteristics to achieve a consistent perception of the aircraft's motion in space by the pilot based on a consistent control method. The goal is to achieve consistent control across different modes and aircraft types, enabling translational maneuvers between multiple aircraft types and models.

[0062] 2. Control stick operation characteristics design

[0063] The control stick has two degrees of freedom: the pitch stick and the yaw stick. In fixed-wing mode, the pitch stick controls the pitch rate or overload command, which, through corresponding control calculations and servo drives, causes the elevator to deflect, thus changing the aircraft's flight state. In vertical takeoff and landing (VTOL) mode, it controls the vertical speed command, which, under vectoring nozzles, distributes the lift fan and main engine throttle opening to achieve longitudinal attitude balance and vertical speed control. In fixed-wing mode, the yaw stick generates the roll rate command, which, through control calculations and driven by the servo system, causes the ailerons to deflect, changing the aircraft's roll rate. In VTOL mode, it controls the lateral acceleration command. During control, it is necessary to balance the yaw moment while generating lateral force. This balance is achieved by adjusting the lateral deflection angles of the lift fan and the tailpipe. The superposition of these two forces generates a lateral force, causing the aircraft to translate laterally. During this process, the roll nozzle needs to be controlled to maintain roll attitude stability.

[0064] 3. Throttle control characteristics design

[0065] The throttle has only one degree of freedom of control and two modes: acceleration mode, corresponding to the fixed thrust command in fixed-wing mode, and speed mode, corresponding to the forward speed command. Both provide the required thrust by adjusting the main engine throttle and the longitudinal deflection of the exhaust nozzle. In acceleration mode, the active throttle console is required to hold the lever when released; in speed mode, the active throttle console is required to return the lever to zero when released.

[0066] 4. Foot pedal control design

[0067] The foot pedals correspond to yaw rate commands in both states. In fixed-wing mode, they generate yaw torque by driving the rudder, thereby changing the heading. In vertical takeoff and landing mode, by adjusting the lateral deflection angle of the lift fan and micro-jet nozzle, a corresponding yaw torque is generated under the condition of pitch torque balance, so that the heading can be controlled by hovering around a fixed point. During the process, the roll nozzle needs to be controlled to achieve roll attitude stability.

[0068] 5. Throttle-Acceleration Control / Forward Speed ​​Control

[0069] The control strategies for acceleration and speed modes are consistent, affecting two aspects: firstly, adjusting the total thrust through throttle input, and secondly, distributing forward thrust through the longitudinal deflection angle of the exhaust nozzle. In speed mode, altitude hold is generally maintained. Taking speed mode as an example:

[0070] PLA_forvel(t)=PLA0_forvel+K_P_forvel*(Vb_x_ref(t)-Vb_x(t))+K_I_forvel* ∫(Vb_x_ref(t)-Vb_x(t))dt+K_P_H*(H_ref(t)-H(t))+K_I_H*∫(H_ref(t)-H(t))dt

[0071] PLA_y_angle(t)=Angle0+K_P_y_angle*(Vb_x_ref(t)-Vb_x(t))+K_I_y_angle*∫(Vb_x_ref(t)-Vb_x(t))dt

[0072] Wherein, Vb_x_ref(t) is the forward speed command, Vb_x(t) is the forward speed feedback, H_ref(t) is the altitude command, and H(t) is the altitude feedback. The throttle opening component PLA_forvel(t) and the nozzle longitudinal deflection angle PLA_y_angle(t) are given simultaneously through proportional-integral (PI) calculation. K_P_forvel, K_I_forvel, K_P_H, K_I_H, K_P_y_angle, and K_I_y_angle are the corresponding proportional-integral (PI) parameters. Angle0 is the initial preset value of the nozzle longitudinal deflection angle. The preset value is 0° when transitioning from hovering to cruising and 90° when transitioning from cruising to hovering. PLA0_forvel is the throttle preset value.

[0073] In acceleration mode, the above control uses acceleration commands and acceleration feedback to achieve forward acceleration closed loop through throttle opening and tail nozzle longitudinal deflection angle; or directly corresponds to thrust commands, and obtains the required thrust by adjusting throttle opening.

[0074] 6. Control stick longitudinal stick - vertical speed control

[0075] In vertical takeoff and landing mode, the required lift is provided by adjusting the thrust of the main engine, while the lift fan stabilizes the pitch attitude by balancing the pitch moment.

[0076] PLA_vz(t)=PLA0_vz+K_P_vz*(V_z_ref(t)-V_z(t))+K_I_vz*∫(V_z_ref(t)-V_z(t))dt

[0077] Where V_z_ref(t) is the vertical velocity command corresponding to the longitudinal rod displacement, V_z(t) is the vertical velocity feedback, PLA_vz(t) is the required throttle opening, K_P_vz and K_I_vz are the corresponding control parameters, and PLA0_vz is the throttle preset value.

[0078] 7. Control stick trailing arm - angular rate / overload control

[0079] In fixed-wing mode, enhanced control and stability are achieved through feedback of angular rate, angle of attack, and overload in the inner loop. Based on this, at low speeds, the pitch control command corresponds to the angular rate command, and the elevator command is generated through the angular rate closed loop. At high speeds, the pitch control command corresponds to the overload command, and the elevator command is generated through the overload closed loop, which ultimately drives the control surfaces to deflect and change the flight state of the aircraft.

[0080] 8. Control stick crossbar - lateral speed control

[0081] In vertical takeoff and landing mode, the horizontal bar corresponds to the lateral speed command, which realizes the translation of the lateral position. It mainly drives the lift fan and tail nozzle to provide lateral force by adjusting the deflection angle. During the process, the rolling nozzle is required to balance the rolling attitude.

[0082] PLA_z_angle(t)=K_P_z_angle*(Vb_y_ref(t)-Vb_y(t))+K_I_z_angle*∫(Vb_y_ref(t)-Vb_y(t))dt

[0083] Where Vb_y_ref(t) is the lateral velocity command corresponding to the crossbar travel, Vb_y(t) is the actual lateral velocity feedback, PLA_z_angle(t) is the lateral deflection angle of the tail nozzle, and K_P_z_angle and K_I_z_angle are the corresponding control parameters.

[0084] Lateral deflection generates lateral force and yaw moment. The lift fan needs to deflect accordingly to counteract the yaw moment generated by the main engine and tail nozzle, thereby achieving lateral position translation.

[0085] 9. Control of the control stick crossbar and roll rate

[0086] In fixed-wing mode, roll characteristics are improved through feedback such as the angular rate and sideslip angle of the inner loop. Based on this, stick commands generate corresponding roll angular rate commands to achieve closed-loop control of the roll angular rate, and output to drive the ailerons to change the flight state of the aircraft.

[0087] 10. Foot pedal-yaw rate control

[0088] Regardless of whether it is rotor / vertical takeoff and landing mode or fixed-wing mode, the pedals correspond to the yaw rate command. In fixed-wing mode, the rudder is driven by the yaw rate closed loop to change the flight state. In vertical takeoff and landing mode, the yaw torque is generated by changing the deflection angle of the lift fan and tail nozzle, thereby achieving on-the-spot heading adjustment. During the process, the roll nozzle is required to maintain the roll attitude.

[0089] The following section discusses the generation of control strategies or commands for flight control procedures under both manual and automatic scenarios, based on the aforementioned technologies:

[0090] Example 1: Artificial Flight

[0091] Step 1: With the ground stationary, power on the equipment and start the engine. At this time, the tail nozzle is at 90°, the roll nozzle and lift fan are on, and the control surface deflection is at the preset value. Because the speed is low, there will be no significant aerodynamic impact on the flight status. The control stick, throttle, and pedals are all at zero position.

[0092] Step 2: Pull the control stick back. This generates an upward vertical speed command. According to technical point 6, the required throttle opening is generated. FADEC then drives the engine to generate the corresponding thrust, and the aircraft changes its upward motion. During this process, in order to maintain the balance of pitch attitude, the lift fan needs to generate a corresponding force to balance the pitch moment.

[0093] Step 3: Adjust the heading during the process. If a leftward yaw is needed, depress the left rudder pedal. According to Technique Point 10, the tail nozzle deflects to the left, and the lift fan deflects to the right, generating a negative yaw moment, which in turn causes the nose to yaw to the left. If a rightward yaw is needed, depress the right rudder pedal. According to Technique Point 10, the tail nozzle deflects to the right, and the lift fan deflects to the left, generating a positive yaw moment, which in turn causes the nose to yaw to the right. During this process, the roll nozzle needs to be used in conjunction to maintain the roll attitude.

[0094] Step 4: During the process, lateral translation is required. If leftward translation is needed, the left stick is pressed down. According to technical point 8, the tail nozzle deflects to the right, and the lift fan also deflects to the right, offsetting the yaw moment and generating a combined lateral force to the left, causing the aircraft to translate to the left. If rightward translation is needed, the right stick is pressed down. According to technical point 8, the tail nozzle deflects to the left, and the lift fan also deflects to the left, offsetting the yaw moment and generating a combined lateral force to the right, causing the aircraft to translate to the right.

[0095] Step 5: After the aircraft ascends to a certain stage, it maintains a hovering state, at which point all control devices return to zero. Next, the throttle is pushed forward, generating forward acceleration. This process achieves altitude hold, generating corresponding throttle opening commands and tailpipe longitudinal deflection angles according to technical point 5. Due to the increased speed, aerodynamic forces will affect flight. Since the control stick and pedals are not deflected, the corresponding commands are 0. Attitude will be stabilized by controlling the control surfaces according to technical points 7, 9, and 10.

[0096] Step 6: When the speed reaches a certain value, the deflection angle of the tail nozzle will approach 0°. Switch from vertical takeoff and landing mode to fixed-wing mode by pressing the toggle switch. The tail nozzle will transition to 0°, and the lift fan and roll nozzle will be turned off. At this time, control of the fixed-wing aircraft can be achieved by operating the control stick, throttle, and pedals according to technical points 5, 7, 9, and 10.

[0097] Step 7: To switch from fixed-wing mode to vertical takeoff and landing (VTOL) mode, you first need to decelerate. After reaching the transition corridor, switch to VTOL mode via the button. At this time, the throttle stick is at its maximum deflection position, and the control stick and pedals are at zero. During this process, reduce the throttle stick to achieve constant altitude deceleration flight. According to technical point 5, control the throttle opening and the longitudinal deflection angle of the tail nozzle is achieved. Due to the high speed, according to technical points 7, 9, and 10, the attitude will be stabilized by controlling the control surfaces.

[0098] Step 8: Gradually reduce the throttle to zero. At this point, the aircraft should be hovering. Then, according to technical point 10, adjust the aircraft's heading by pressing the pedals. According to technical point 8, adjust the aircraft's lateral position by pressing the left stick.

[0099] Step 9: Pull back the control stick to generate downward vertical acceleration. According to technical point 6, adjust the throttle opening of the main engine. The lift fan will work together to maintain the longitudinal attitude, gradually reduce the flight altitude, and then achieve landing.

[0100] Example 2: Automatic Flight

[0101] Step 1: Ground status, power on the equipment, start the engine, and enter the ground waiting phase. Click takeoff, set the hovering altitude, calculate the vertical rate based on the hovering altitude, and generate the throttle opening command in conjunction with technical point 6. The lift fan will then adjust the opening to maintain the pitch attitude.

[0102] Step 2: During the process, maintain a stable heading and zero roll attitude. To control heading stability, a yaw rate command is generated based on the deviation from the current heading, and the tail nozzle and lift fan are deflected accordingly according to technical point 10 to adjust the heading; to achieve zero roll attitude, differential control of the roll nozzle is used to achieve the desired purpose.

[0103] Step 3: Enter the hovering phase. Given a forward acceleration command, and based on the current hovering altitude, obtain the main engine throttle opening command and the tailpipe longitudinal deflection command according to technical point 5. This enables control of the corresponding equipment, generating forward thrust. During this process, pitch, roll, and heading commands need to be given. By interacting with the corresponding feedback states and combining technical points 7, 9, and 10, the corresponding control surfaces are controlled.

[0104] Step 4: When the speed reaches a certain value, automatically switch to fixed-wing mode and fly along the flight path according to technical points 5, 7, 9 and 10.

[0105] Step 5: When switching from fixed-wing mode to vertical takeoff and landing mode, automatic switching is achieved when deceleration reaches a certain stage. Based on the current altitude and forward acceleration command, the main engine throttle opening and tail nozzle longitudinal deflection angle are controlled in conjunction with technical point 5 to decelerate to a hovering state.

[0106] Step 6: When the hovering point does not match the desired position, the position and heading are adjusted by combining forward deviation, lateral deviation, and heading deviation with technical points 5, 8, and 10.

[0107] Step 7: In the hovering state, the given altitude command is zero. Combined with technical point 6, the throttle opening of the main engine and lift fan is controlled to achieve a smooth ground touchdown.

[0108] The technical solution of this invention provides a complete method for solving vertical takeoff and landing flight control, which can quickly adapt to the flying habits of vertical takeoff and landing mode and fixed-wing mode without causing differences in control perception, reduce the economic and time costs of pilot training, improve the control technology of aircraft, and promote the application and popularization of manned / unmanned aircraft in limited sites and airspaces.

Claims

1. A unified vertical takeoff and landing / fixed-wing control mode, characterized in that, The control mode is applied to a vertical takeoff and landing fixed-wing aircraft, which includes at least: a lift fan and a main engine; The lift fan generates the pitching moment and the required yaw moment by adjusting the throttle opening and its own longitudinal and lateral yaw angles; The main engine is equipped with a three-bearing vector nozzle at the tail. The three-bearing vector nozzle can deflect at any angle in the longitudinal and lateral directions to provide thrust or lift to the airframe, as well as the yaw torque required for the airframe to deflect. Roll nozzles are installed on both sides of the wing. By extracting the flow rate from the main bypass duct, a downward airflow is generated. This allows for deviation control of the roll nozzle flow rate, thereby adjusting the aircraft's roll attitude. The mode is as follows: Longitudinal control of the control stick corresponds to changes in vertical position, lateral control of the control stick corresponds to changes in lateral position, throttle control corresponds to changes in forward position, and pedal control corresponds to changes in heading. The throttle control corresponds to changes in forward position, including acceleration control and forward speed control, specifically implemented as follows: In forward speed control mode: in, Forward speed command, For forward velocity feedback, For altitude instructions, For high feedback, the throttle opening component is simultaneously calculated using a proportional-integral method. and tail nozzle longitudinal deflection angle , , , , , and These are the corresponding PI parameters. This is the initial preset value for the longitudinal deflection angle of the tail nozzle. The preset value is 0° when transitioning from hovering to cruise, and 90° when transitioning from cruise to hover. This is the preset throttle value; In acceleration control mode, acceleration commands and acceleration feedback are used to achieve forward acceleration closed loop through throttle opening and tail nozzle longitudinal deflection angle.

2. The unified vertical takeoff and landing / fixed-wing control mode according to claim 1, characterized in that, The longitudinal control of the joystick corresponds to changes in vertical position, including: vertical speed control and angular rate / overload control; Vertical speed control in vertical takeoff and landing mode provides the required lift by adjusting the thrust of the main engine, while the lift fan stabilizes the pitch attitude based on the pitch moment balance. in, This is the vertical velocity command corresponding to the displacement of the longitudinal rod. For vertical velocity feedback, The required throttle opening. and For the corresponding control parameters, This is the preset throttle value; In fixed-wing mode, angular rate / overload control is enhanced through feedback of angular rate, angle of attack, and overload to improve control and stability. Based on this, at low speeds, the pitch control command corresponds to the angular rate command, and the elevator command is generated through the angular rate closed loop. At high speeds, the pitch control command corresponds to the overload command, and the elevator command is generated through the overload closed loop, which ultimately drives the control surfaces to deflect and change the flight state of the aircraft.

3. The unified vertical takeoff and landing / fixed-wing control mode according to claim 1, characterized in that, The changes in lateral position corresponding to the lateral control of the control stick include: control stick horizontal bar-lateral speed control and control stick vertical bar-roll rate control; In vertical takeoff and landing mode, the horizontal bar corresponds to the lateral speed command, which realizes the translation of the lateral position, drives the deflection angle of the lift fan and the main engine to provide lateral force, and the rolling nozzle needs to balance the rolling attitude during the process. in This is the lateral speed command corresponding to the crossbar travel. For actual lateral velocity feedback, The lateral deflection angle of the main engine's exhaust nozzle. and For the corresponding control parameters; Lateral deflection generates lateral force and yaw moment. The lift fan needs to deflect accordingly to counteract the yaw moment generated by the main engine exhaust nozzle, thereby achieving lateral position translation. In fixed-wing mode, roll characteristics are improved through angular rate and sideslip angle feedback. Based on this, the stick command generates the corresponding roll angular rate command to achieve closed-loop control of the roll angular rate, and outputs to drive the ailerons to change the flight state of the aircraft.

4. The unified vertical takeoff and landing / fixed-wing control mode according to claim 1, characterized in that, The pedal control corresponds to changes in heading, specifically: Regardless of whether it is rotor / vertical takeoff and landing mode or fixed-wing mode, the foot pedals correspond to the yaw rate command. In fixed-wing mode, the flight state is changed by driving the rudder through a closed-loop yaw rate drive. In vertical takeoff and landing mode, yaw moment is generated by changing the deflection angle of the lift fan and the main engine exhaust nozzle, thereby achieving on-the-spot heading adjustment. During this process, the roll nozzle is required to maintain the roll attitude.

5. A unified vertical takeoff and landing / fixed-wing control method, characterized in that, Implemented using the control mode described in any one of claims 1-4, in manual flight mode, the method includes: Step 1: With the ground stationary, power on the equipment and start all engines. At this time, the tail nozzle is at 90°, the roll nozzle and lift fan are turned on, the control surface deflection is at the preset value, and the control stick, throttle, and pedals are all at zero. Step 2: Pull the control stick back. This generates an upward vertical speed command. The required throttle opening is generated based on the vertical speed control of the control stick. The full authority digital engine control system (FADEC) drives the engine to generate the corresponding thrust, and the aircraft changes its upward motion. During this process, in order to maintain the balance of pitch attitude, the lift fan needs to generate a corresponding force to balance the pitch moment. Step 3: Adjust the heading during flight. If a left yaw is required, depress the left rudder pedal. According to the pedal-yaw rate control, the tail nozzle deflects to the left and the lift fan deflects to the right, generating a negative yaw moment, which in turn causes the nose to yaw to the left. If a right yaw is required, depress the right rudder pedal. According to the pedal-yaw rate control, the tail nozzle deflects to the right and the lift fan deflects to the left, generating a positive yaw moment, which in turn causes the nose to yaw to the right. During this process, the roll nozzle needs to be used in conjunction to maintain the roll attitude. Step 4: Lateral translation during flight. If leftward translation is required, push the control stick to the left. According to the control stick horizontal stick-lateral speed control, the tail nozzle deflects to the right, and the lift fan also deflects to the right to counteract the yaw moment. The combined effect generates a lateral force to the left, causing the aircraft to translate to the left. If rightward translation is required, push the control stick to the right. According to the control stick horizontal stick-lateral speed control, the tail nozzle deflects to the left, and the lift fan also deflects to the left to counteract the yaw moment. The combined effect generates a lateral force to the right, causing the aircraft to translate to the right. Step 5: After the aircraft ascends to a certain stage, it remains in a hovering state. At this time, all operating devices return to zero. Then, push the throttle forward to generate forward acceleration. This process achieves altitude hold flight. According to the throttle-acceleration control / forward speed control, the corresponding throttle opening command and tail nozzle longitudinal deflection angle are generated. Since the control stick and pedals are not deflected, the corresponding command is zero. According to the control stick longitudinal stick-angular rate / overload control, control stick transverse stick-roll angular rate control, and pedals-yaw angular rate control, the attitude is stabilized by controlling the control surfaces. Step 6: When the speed reaches a certain value, the deflection angle of the tail nozzle will approach 0°. Switch from vertical take-off and landing mode to fixed-wing mode by pressing the toggle switch. The tail nozzle will transition to 0°, and the lift fan and roll nozzle will be turned off. At this time, control of the fixed-wing aircraft can be achieved by operating the control stick, throttle, and pedals according to the throttle-acceleration control / forward speed control, control stick vertical stick-angular rate / overload control, control stick horizontal stick-roll angular rate control, and pedal-yaw angular rate control. Step 7: To switch from fixed-wing mode to vertical takeoff and landing mode, you first need to decelerate. After reaching the transition corridor, switch to vertical takeoff and landing mode via the button. At this time, the throttle stick is at the maximum deflection position, and the control stick and pedals are at zero. During this process, reduce the throttle stick to achieve constant altitude deceleration flight. The throttle opening and tail nozzle longitudinal deflection angle are controlled by throttle-acceleration control / forward speed control. Due to the high speed, the attitude is stabilized by controlling the control surfaces by controlling the control stick longitudinal stick-angular rate / overload control, control stick lateral stick-roll angular rate control, and pedal-yaw angular rate control. Step 8: Gradually reduce the throttle to zero. At this point, the aircraft should be hovering. Then, adjust the aircraft's heading by pressing the pedals according to the yaw rate control, and adjust the aircraft's lateral position by pressing the left control stick according to the stick control. Step 9: Pull back the control stick to generate downward vertical acceleration. Adjust the throttle opening of the main engine according to the vertical speed control of the control stick. The lift fan works in conjunction to maintain the longitudinal attitude, gradually reduce the flight altitude, and then achieve landing.

6. A unified vertical takeoff and landing / fixed-wing control method, characterized in that, Implemented using the control mode described in any one of claims 1-4, in automatic flight mode, the method includes: Step 1: Ground status, power on the equipment, start the engine, and enter the ground waiting phase. Click takeoff, set the hovering altitude, calculate the vertical rate based on the hovering altitude, and generate the throttle opening command in combination with the control stick pitch control. The lift fan adjusts the opening to maintain the pitch attitude. Step 2: During flight, maintain a stable heading and zero roll attitude. To control heading stability, a yaw rate command is generated based on the deviation from the current heading. The tail nozzle and lift fan are deflected accordingly based on the pedal-yaw rate control to adjust the heading. The roll attitude is zeroed through differential control of the roll nozzle. Step 3: Enter the hovering phase. Given a forward acceleration command, and combined with the current hovering height, the main engine throttle opening command and the longitudinal deflection angle command of the tail nozzle are obtained according to the throttle-acceleration control / forward speed control. This enables control of the corresponding equipment and generates forward thrust. During this process, pitch attitude command, roll attitude command, and heading command need to be given. Through corresponding status feedback, the corresponding control surfaces are controlled in combination with the control stick pitch-angular rate / overload control, control stick yaw rate control, and pedal-yaw rate control. Step 4: When the speed reaches a certain value, it automatically switches to fixed-wing mode and flies along the route based on throttle-acceleration control / forward speed control, control stick pitch control-angular rate / overload control, control stick yaw rate control and pedal control-yaw rate control. Step 5: When switching from fixed-wing mode to vertical takeoff and landing mode, automatic switching is achieved when deceleration reaches a certain stage. Based on the current altitude and forward acceleration command, the main engine throttle opening and tail nozzle longitudinal deflection angle are controlled in combination with throttle-acceleration control / forward speed control to decelerate to a hovering state. Step 6: When the hovering point does not match the desired position, the position and heading are adjusted by combining forward deviation, lateral deviation, and heading deviation with throttle-acceleration control / forward speed control, control stick-lateral speed control, and pedal-yaw rate control. Step 7: In the hovering state, the given height command is zero. Combined with the control stick longitudinal stick-vertical speed control, the throttle opening of the main engine and lift fan is controlled, thereby achieving a smooth ground contact.

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