Flap control method for take-off and landing stages of unmanned ground-effect wing ship
By simultaneously controlling flap retraction and extension during the takeoff and landing phases of the unmanned ground effect vehicle, and by establishing a linear relationship between the control quantity and the reciprocal of the dynamic pressure, the problem of lift instability during flap retraction and extension was solved, achieving stable lift and smooth control of speed and altitude, thus improving flight safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN AISHENG TECH GRP
- Filing Date
- 2025-12-10
- Publication Date
- 2026-04-10
AI Technical Summary
During takeoff and landing, the lift of unmanned ground effect vehicles is difficult to maintain during flap deployment and retraction, resulting in violent fluctuations in speed and altitude.
The flap control method is adopted, which involves simultaneously retracting and accelerating the flaps during takeoff and simultaneously releasing and decelerating the flaps during landing. The control quantity is linearly related to the reciprocal of the dynamic pressure, and the flap control quantity is adjusted in real time to maintain lift stability.
It achieved stable lift during the take-off and landing of the unmanned ground effect vehicle, ensuring smooth changes in speed and altitude, and improving flight safety and control precision.
Smart Images
Figure CN121822908A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of unmanned aerial vehicles, and in particular to a flap control method for the take-off and landing phase of an unmanned ground effect vehicle. Background Technology
[0002] Ground effect vehicles (GEVs) are special-purpose aircraft that utilize the ground effect principle, enabling them to fly at extremely low altitudes. When a GEV flies close to the ground or water surface, the airflow over the wing moves downwards and backwards, generating a reaction force from the ground or water surface. This increases the vertical pressure difference across the entire aircraft, resulting in a sharp increase in lift and a decrease in drag, preventing the wing from drooping. This physical phenomenon, which reduces induced drag and achieves a higher lift-to-drag ratio than airborne flight, is known as the ground effect. GEVs can fly at high speeds at low altitudes close to the ground or water surface and have broad application prospects in military, civilian aviation, and marine technology.
[0003] Due to their large size, high speed, low altitude, and high inertia, unmanned ground effect vehicles (GEVs) require automatic control systems to ensure flight safety. The control system of a GEV needs to guarantee good motion stability and maneuverability, with speed and altitude control during takeoff and landing being particularly critical. During takeoff, the GEV uses flaps to increase lift and reduce takeoff speed; after leaving the water, the flaps retract to increase speed. During landing, the GEV deploys flaps to reduce descent speed. GEV flaps typically have a large area and a high lift coefficient when fully deployed, leading to drastic changes in lift coefficient during flap deployment and retraction. If traditional flap deployment strategies (such as constant-speed deployment and retraction) are used, the lift experienced by the GEV during takeoff and landing is difficult to maintain stability, resulting in violent fluctuations in speed and altitude. Summary of the Invention
[0004] The main purpose of this application is to provide a flap control method for the take-off and landing phase of an unmanned ground effect vehicle, which aims to solve the problem that the lift of the ground effect vehicle is difficult to maintain during the take-off and landing phase in the existing flap deployment and retraction strategies.
[0005] To achieve the above objectives, this application provides a flap control method for the takeoff and landing phases of an unmanned ground effect vehicle (GEV), comprising: simultaneously performing flap retraction and acceleration during the climb and level flight phases of the GEV takeoff process; wherein the takeoff flap control quantity is used as the retraction control output; the takeoff flap control quantity is determined based on the GEV's weight, wing area, and takeoff dynamic pressure during the takeoff phase, and the takeoff flap control quantity is linearly related to the reciprocal of the takeoff dynamic pressure; simultaneously performing flap release and deceleration during the level flight phase of the GEV landing process; wherein the landing flap control quantity is used as the release control output; the landing flap control quantity is determined based on the GEV's weight, wing area, and landing dynamic pressure during the landing phase, and the landing flap control quantity is linearly related to the reciprocal of the landing dynamic pressure.
[0006] Optionally, the takeoff dynamic pressure is the dynamic pressure collected in real time during the acceleration of the ground effect vehicle from a safe speed to a cruising speed; the landing dynamic pressure is the dynamic pressure collected in real time during the deceleration of the ground effect vehicle from a cruising speed to a landing speed.
[0007] Optionally, the linear relationship between the takeoff flap control amount and the reciprocal of the takeoff dynamic pressure is as follows: (5); In the formula, For takeoff flap control, For takeoff dynamic pressure, For wing area, For the mass of the ground effect vehicle, It is the acceleration due to gravity; and These are the proportional value and the deviation term of the linear function, respectively, both determined based on the dynamic pressure before and after the flaps retract during the climb and level flight phases.
[0008] Optionally, and The expression is: (7); In the formula, The dynamic pressure before the flaps retract during the climb and level flight phases. The dynamic pressure after the flaps are retracted during the climb and level flight phases. This represents the maximum flap angle. This represents the minimum flap and rudder angle. Optionally, the linear relationship between the landing flap control amount and the reciprocal of the landing dynamic pressure is as follows: (9); In the formula, For landing flap control, To reduce dynamic pressure, For wing area, For the mass of the ground effect vehicle, It is the acceleration due to gravity; and These are the proportional value and the deviation term of the linear function, respectively, both determined based on the dynamic pressure before and after flap release during the level flight phase.
[0009] Optionally, and The expression is: (11); In the formula, This refers to the dynamic pressure before the flaps are released during level flight. This refers to the dynamic pressure after the flaps are released during level flight. This represents the maximum flap angle. This is the minimum flap rudder angle.
[0010] Optionally, it also includes: comparing the takeoff flap control amount with the minimum flap rudder angle and the current flap rudder angle respectively; when the takeoff flap control amount is less than the minimum flap rudder angle, the minimum flap rudder angle is used as the retraction control output; when the takeoff flap control amount is greater than the current flap rudder angle, the current flap rudder angle is used as the retraction control output.
[0011] Optionally, it also includes: comparing the landing flap control amount with the maximum flap angle and the current flap angle respectively; when the landing flap control amount is greater than the maximum flap angle, using the maximum flap angle as the release control output; when the landing flap control amount is less than the current flap angle, using the current flap angle as the release control output.
[0012] Compared with the prior art, the beneficial effects of this application are as follows: The flap control method for unmanned ground effect vehicles (GEVs) of the present invention simultaneously accelerates and retracts flaps during the climb and level flight phases of the GEV takeoff process to compensate for the lift loss caused by the decrease in lift coefficient. During the level flight phase of the GEV landing process, it simultaneously decelerates and releases flaps to eliminate the additional lift caused by the increase in lift coefficient, thereby ensuring lift stability. The flap control quantity of the unmanned GEV is expressed as a linear function of the reciprocal of dynamic pressure, so that the flap retraction and extension are adapted to the speed changes during takeoff and landing, further ensuring lift stability and facilitating smooth changes in speed and altitude during takeoff and landing. Attached Figure Description
[0013] Figure 1 This is a flowchart illustrating the takeoff process of the flap control method for the takeoff and landing phase of an unmanned ground effect vehicle according to this application. Figure 2 This is a schematic diagram of the landing process of the flap control method for the take-off and landing phase of an unmanned ground effect vehicle according to this application. Figure 3 This is a flowchart illustrating the process of determining the first output control in an embodiment. Figure 4 This is a schematic diagram of the process for determining the second output control in an embodiment.
[0014] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0015] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0016] It is worth noting that the lift of the unmanned ground effect vehicle... The calculation formula is: (1); In the formula, The lift coefficient, For dynamic pressure, For wing area, air density, Where is the vacuum velocity. The formula for calculating the lift coefficient is: (2); In the formula, The basic lift coefficient, This is the derivative of the lift coefficient with respect to the rate of attack. This is the derivative of the lift coefficient with respect to the pitch rate. Let be the derivative of the lift coefficient with respect to the elevator. The derivative of the lift coefficient with respect to the flaps. The average geometric chord length of the wing. For the angle of attack, For pitch rate, For elevator control parameters, This refers to the flap control amount.
[0017] Because unmanned ground effect vehicles typically have large flaps, they possess high... , In lift coefficient It accounts for a large proportion of the various components. Therefore, during the flap deployment and retraction process, the lift coefficient... Dramatic changes will occur. The lift experienced by the unmanned ground effect vehicle is simultaneously affected by the lift coefficient. and speed (or dynamic pressure) The impact of flap retraction. For the reasons mentioned above, the ground effect vehicle needs to continuously accelerate during flap retraction (thus increasing dynamic pressure). To compensate for the lift coefficient To reduce lift loss; during flap deployment, the ground effect vehicle needs to continuously decelerate (thus reducing dynamic pressure). To eliminate the lift coefficient The increased lift results in additional lift. In summary, to maintain stable lift, the flap control amount... Should be related to speed (or dynamic pressure) Adapt to changes in ).
[0018] In addition, to ensure a smooth ascent or descent during takeoff and landing, the lift force experienced by the unmanned ground effect vehicle should remain constant and equal to its weight, i.e. (3); In the formula, For the mass of the ground effect vehicle, For gravitational acceleration. Under the condition that the ground effect vehicle is in a stable attitude and flying at a low altitude, the lift coefficient in equation (2) is... The first four terms can be approximated as unchanged. Combining equations (2) and (3), we get: (4); Therefore, to maintain a constant lift on the unmanned ground effect vehicle, the flap control amount should be approximately linearly related to the reciprocal of the dynamic pressure. Based on the above analysis, this invention expresses the flap control amount as a linear function of the reciprocal of the dynamic pressure, thereby adjusting the flap control amount in real time to achieve a constant lift on the unmanned ground effect vehicle, as detailed below.
[0019] An embodiment of the present invention provides a flap control method for the take-off and landing phase of an unmanned ground effect vehicle, specifically including the following steps: Step S1: During the takeoff of the ground effect vehicle, the flaps are retracted and the acceleration is performed simultaneously during the climb and level flight phases. Specifically, the takeoff flap control value is used as the retraction control output; the takeoff flap control value is determined based on the gravity, wing area, and takeoff dynamic pressure of the ground effect vehicle during the takeoff phase, and the takeoff flap control value is linearly related to the reciprocal of the takeoff dynamic pressure; the takeoff dynamic pressure is the dynamic pressure collected in real time during the acceleration of the ground effect vehicle from the safe speed to the cruise speed; the linear relationship is as follows: (5); In the formula, For takeoff dynamic pressure, For wing area, For the mass of the ground effect vehicle, It is the acceleration due to gravity; and These are the proportional value and the deviation term of the linear function, respectively, determined based on the dynamic pressure before and after the flaps retract during the climb and level flight phases.
[0020] Furthermore, due to Corresponding safe speed (The corresponding dynamic pressure is) ), ( Corresponding cruising speed (The corresponding dynamic pressure is) ).therefore, and The solution can be obtained by solving the following simultaneous equations: (6); Solving for: (7); In the formula, The dynamic pressure before the flaps retract during the climb and level flight phases. The dynamic pressure after the flaps are retracted during the climb and level flight phases. This represents the maximum flap angle. This is the minimum flap rudder angle.
[0021] Since the flap retraction control output should be limited to the maximum flap angle during the flap retraction process. Minimum value of flap and rudder angle Therefore, the takeoff flap control value obtained above should be compared with the maximum flap angle and the larger value should be taken to avoid exceeding the limit of the retraction control output. That is, when the takeoff flap control value is less than the minimum flap angle, the minimum flap angle should be used as the retraction control output to control the flap retraction. To prevent the takeoff flap control value from adjusting in the opposite direction due to changes in dynamic pressure disturbance, the takeoff flap control value should be compared with the current flap angle in real time. The smaller value is selected to avoid increasing the retraction control output; that is, when the takeoff flap control value is greater than the current flap angle, the current flap angle is used as the retraction control output to control flap retraction. The expression for the retraction control output is: (8).
[0022] Specifically, such as Figure 1 As shown, the complete control process for the takeoff of the ground effect vehicle in this embodiment is as follows: a) Water taxiing phase: Align the ground effect vehicle with the takeoff direction and release the flaps to the maximum flap angle (maximum control surface value). After the flaps are fully extended, the engine is given maximum throttle to accelerate the ground effect vehicle to liftoff speed. The attitude control mode is water surface gliding control mode, and the elevator is fixed. The heading is controlled by differential engine throttle and rudder, and the heading command is the current heading.
[0023] b) Takeoff Phase: The ground effect vehicle reaches takeoff speed Subsequently, the longitudinal control mode is pitch control, which raises the nose of the ground effect vehicle to the given pitch angle command and lifts it off the water; the lateral control mode maintains the roll angle at [value missing]. .
[0024] c) Climbing Phase: The ground effect vehicle reaches a safe altitude. and speed Then, the engine control mode was switched to speed control, and the speed command was set to cruise speed. The longitudinal control mode was changed to vertical velocity control based on pitch angle; the flaps were gradually retracted to the minimum flap angle by controlling the retraction control output. (Right now Meanwhile, the ground effect vehicle continues to accelerate and climb steadily.
[0025] d) Level flight phase: The ground effect vehicle reaches cruising altitude Then, longitudinal control was changed to height hold, and the height command was... If the flaps are not fully retracted, the ground effect vehicle continues to accelerate to cruising speed. Its rear flaps remain The speed is maintained at The takeoff process is now complete.
[0026] Step S2: During the descent of the ground effect vehicle (GEV), the flaps are released and deceleration are performed simultaneously during the level flight phase. The descent flap control value is used as the release control output. This descent flap control value is determined based on the GEV's weight, wing area, and descent dynamic pressure during the descent phase, and it has a linear relationship with the reciprocal of the descent dynamic pressure. The descent dynamic pressure is the dynamic pressure collected in real-time during the GEV's deceleration from cruising speed to descent speed. Specifically, this linear relationship is as follows: (9); In the formula, and These are the scale value and the deviation term of the linear function, respectively. To reduce dynamic pressure, For wing area, For the mass of the ground effect vehicle, It is the acceleration due to gravity; and Determined based on the dynamic pressure before and after flap release during level flight.
[0027] Furthermore, due to Corresponding descent speed (The corresponding dynamic pressure is) ), ( Corresponding cruising speed (The corresponding dynamic pressure is) ).therefore, and The solution can be obtained by solving the following simultaneous equations: (10); (11); In the formula, This refers to the dynamic pressure before the flaps are released during level flight. This refers to the dynamic pressure after the flaps are released during level flight. This represents the maximum flap angle. This is the minimum flap rudder angle.
[0028] Since the release control output during flap deployment should be limited to the maximum flap angle... Minimum value of flap and rudder angle Therefore, the landing flap control value obtained above should be compared with the maximum flap angle and the smaller value should be taken to avoid the release control output exceeding the limit. That is, when the landing flap control value is greater than the maximum flap angle, the maximum flap angle will be used as the release control output.
[0029] To prevent the landing flap control from adjusting in the opposite direction due to changes in dynamic pressure disturbances, the landing flap control should be compared with the current flap angle in real time. The larger value is selected to avoid reducing the release control output; that is, when the landing flap control amount is less than the current flap angle, the current flap angle is used as the release control output. Release control output The expression is: (12).
[0030] Specifically, such as Figure 2 As shown, the complete control process for the landing of the ground effect vehicle in this embodiment is as follows: a) Level flight phase: The ground effect vehicle enters the predetermined landing path. The longitudinal control mode is altitude hold based on pitch angle, and the altitude command is... The lateral control mode maintains the roll angle at a certain value. The engine control mode is speed control, and the speed command is the descent speed. By releasing the control output, the flaps are gradually released until the flap angle reaches its maximum value. Meanwhile, the ground effect vehicle's cruising speed Continue to decelerate to And maintain altitude.
[0031] b) Descent phase: The ground effect vehicle reaches its descent speed Furthermore, after the flaps are fully deployed, the longitudinal control mode switches to pitch control, keeping the nose at the given pitch angle command; the engine control mode switches to throttle-based vertical speed control; and the flaps remain in [position missing]. This allows the ground effect vehicle to glide smoothly.
[0032] c) Leveling-off phase: The ground effect vehicle's altitude decreases to the leveling-off altitude. Then, the vertical speed command is reduced, causing the ground effect vehicle to descend at a slower speed until it enters the water in a fixed attitude.
[0033] d) Water gliding phase: After the ground effect vehicle enters the water, the attitude control mode is switched to water gliding control mode, and the elevator is fixed. The heading command is the current heading; the engine throttle is set to 0, causing the ground effect vehicle's speed to gradually decrease to 0; then the flaps are retracted to the minimum flap rudder angle. (Right now (The landing process is completed.)
[0034] In this embodiment, during the climb and level flight phases of the ground effect vehicle's takeoff, acceleration and flap retraction are performed simultaneously to compensate for the lift loss caused by the decrease in the lift coefficient. During the level flight phase of the ground effect vehicle's landing, deceleration and flap release are performed simultaneously to eliminate the additional lift caused by the increase in the lift coefficient, thereby ensuring lift stability. A linear function of flap control quantity and the reciprocal of dynamic pressure is established to adjust the flap control quantity in real time according to the change in dynamic pressure during acceleration or deceleration, further ensuring lift stability.
[0035] Example 1) Taking an unmanned ground effect vehicle as the object, the basic parameters of the object are: 2) Quality ; 3) Moment of inertia ; 4) Wing area ; 5) Wingspan ; 6) Mean aerodynamic chord of the wing ; 7) Flaps and rudder angle range .
[0036] The takeoff speed of the ground effect vehicle during its takeoff phase To reach a safe speed at a safe altitude cruising speed The dynamic pressure at cruising speed is obtained through sensors. That is, the dynamic pressure after the flaps are retracted during the climb and level flight phases, at a safe speed. That is, the dynamic pressure before the flaps retract during the climb and level flight phases. Substituting this into formula (7) yields:
[0037] The takeoff flap control values during the takeoff phase are:
[0038] Among them, dynamic pressure Measured by sensors. Flange angle limits and current values are taken into account. Due to limitations, the control output was ultimately reduced. A schematic diagram of flap retraction control during the takeoff phase of an unmanned ground effect vehicle is shown below. Figure 3 As shown.
[0039] 8) The cruising speed of the ground effect vehicle during the landing phase. descent speed According to equation (10), we can obtain:
[0040] Therefore, the landing flap control amount during the descent phase is:
[0041] Considering the flap angle limit and current value The limitation is ultimately released, thus releasing the control output. A schematic diagram of flap release control during the landing phase of an unmanned ground effect vehicle is shown below. Figure 4 As shown.
[0042] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.
Claims
1. A flap control method for the takeoff and landing phase of an unmanned ground effect vehicle, characterized in that, include: During the climb and level flight phases of the ground effect vehicle's takeoff, the flaps are retracted and the acceleration process is carried out simultaneously. Among them, the takeoff flap control value is used as the retraction control output; The takeoff flap control amount is determined based on the gravity, wing area and takeoff dynamic pressure of the ground effect vehicle during the takeoff phase, and the takeoff flap control amount is linearly related to the reciprocal of the takeoff dynamic pressure. During the level flight phase of the ground effect vehicle's landing process, the flaps are deployed and the deceleration process is carried out simultaneously. Among them, the landing flap control amount is used as the release control output; The landing flap control amount is determined based on the gravity, wing area, and landing dynamic pressure of the ground effect vehicle during the landing phase, and the landing flap control amount is linearly related to the reciprocal of the landing dynamic pressure.
2. The flap control method for the takeoff and landing phase of an unmanned ground effect vehicle according to claim 1, characterized in that, The takeoff dynamic pressure is the dynamic pressure collected in real time during the acceleration of the ground effect vehicle from a safe speed to a cruising speed; The landing dynamic pressure is the dynamic pressure collected in real time during the process of the ground effect vehicle decelerating from cruising speed to landing speed.
3. The flap control method for the takeoff and landing phase of an unmanned ground effect vehicle according to claim 1, characterized in that, The linear relationship between the takeoff flap control amount and the reciprocal of the takeoff dynamic pressure is as follows: （5）； In the formula, For takeoff flap control, For takeoff dynamic pressure, For wing area, For the mass of the ground effect vehicle, It is the acceleration due to gravity; and These are the proportional value and the deviation term of the linear function, respectively, both determined based on the dynamic pressure before and after the flaps retract during the climb and level flight phases.
4. The flap control method for the takeoff and landing phase of an unmanned ground effect vehicle according to claim 3, characterized in that, and The expression is: （7）； In the formula, The dynamic pressure before the flaps retract during the climb and level flight phases. The dynamic pressure after the flaps are retracted during the climb and level flight phases. This represents the maximum flap angle. This is the minimum flap rudder angle.
5. The flap control method for the takeoff and landing phase of an unmanned ground effect vehicle according to claim 1, characterized in that, The linear relationship between the landing flap control amount and the reciprocal of the landing dynamic pressure is as follows: （9）； In the formula, For landing flap control, To reduce dynamic pressure, For wing area, For the mass of the ground effect vehicle, It is the acceleration due to gravity; and These are the proportional value and the deviation term of the linear function, respectively, both determined based on the dynamic pressure before and after flap release during the level flight phase.
6. The flap control method for the takeoff and landing phase of an unmanned ground effect vehicle according to claim 5, characterized in that, and The expression is: （11）； In the formula, This refers to the dynamic pressure before the flaps are released during the level flight phase. This refers to the dynamic pressure after the flaps are released during level flight. This represents the maximum flap angle. This is the minimum flap rudder angle.
7. The flap control method for the takeoff and landing phase of an unmanned ground effect vehicle according to claim 1, characterized in that, Also includes: Compare the takeoff flap control value with the minimum flap rudder angle and the current flap rudder angle respectively; When the takeoff flap control value is less than the minimum flap angle, the minimum flap angle is used as the retraction control output. When the takeoff flap control value is greater than the current flap rudder angle, the current flap rudder angle will be used as the retraction control output.
8. The flap control method for the takeoff and landing phase of an unmanned ground effect vehicle according to claim 1, characterized in that, Also includes: The landing flap control value is compared with the maximum flap rudder angle and the current flap rudder angle, respectively; When the landing flap control value is greater than the maximum flap angle, the maximum flap angle is used as the release control output. When the landing flap control value is less than the current flap rudder angle, the current flap rudder angle is used as the release control output.