WO2023240862A1 - Rocket-boosted launch and takeoff control method for unmanned aerial vehicle having flying-wing layout - Google Patents

Abstract

The present invention relates to the technical field of aviation flight control. Disclosed is a rocket-boosted launch and takeoff control method for an unmanned aerial vehicle having a flying-wing layout. The method is applicable to the control over a rocket-boosted launch and takeoff process of an unmanned aerial vehicle having a flying-wing layout. A control method that combines elevator pre-provision and pitch angle control is applied to a longitudinal controller, such that an aircraft is dynamically stable in the longitudinal direction at a launch and takeoff stage; roll angle control is applied to a transverse controller, such that wings are maintained flat, and after the aircraft climbs to a safety height, switching to flight trajectory tracking is performed; and a speed-based stability-augmentation softening factor is designed for a heading controller, such that an unmanned aerial vehicle is prevented from adverse disturbance caused by a rudder that is generated by low-speed angle-of-sideslip stability augmentation, and it is ensured that the unmanned aerial vehicle accesses stability augmentation control at a high-speed stage. The present invention is applicable to takeoff control over an unmanned aerial vehicle, which has a flying-wing layout and takes off on the basis rocket boosting.

Description

A flying-wing layout UAV rocket-assisted launch take-off control method Technical field

The invention relates to the technical field of aviation flight control. Specifically, it is a rocket-assisted launch and take-off control method for a flying-wing UAV, which is used to control the launch and take-off process of a flying-wing UAV in a rocket-assisted manner.

Background technique

The launch phase of an aircraft using rocket-assisted launch is often considered one of the most dangerous phases. At present, there are two main methods of launching UAVs: zero-length launch and wheeled take-off. Compared with rolling takeoff, zero-length launch takeoff is not restricted by the site or regional environment, and mission dispatch is more flexible. Rocket-assisted launch Take-off launch is a commonly used launch method for small UAVs. The booster rocket generates propulsion after ignition, accelerating the target drone from a static state to a safe flight height and speed in a short period of time. After the rocket fuel is burned, Automatically disengage, the drone completes takeoff and launch, and then the drone controls the aircraft to perform the mission according to the aerial strategy.

Flying-wing layout UAVs have good aerodynamic efficiency. However, because there is no vertical tail, their heading is statically unstable or weakly statically stable. The sideways slip angle needs to be used for stabilization, and its longitudinal moment arm is short, which will cause longitudinal disturbances. The inhibitory ability is weak. The flying wing layout adopts zero-length launch, which can effectively combine the advantages of zero-length launch with high take-off flexibility and flying-wing layout with high aerodynamic efficiency, but it is difficult to control. During the launch and take-off process, the controller structure, controller access timing, and lateral stability stabilization access timing are crucial to the control quality of the flying-wing layout UAV during the launch and take-off section.

Chinese patent (CN109508027) proposes a rocket-assisted launch method based on robust control theory. This method proposes a longitudinal control method based on angular rate fusion of climb angle. However, this method fails to provide a stable heading. The lateral heading control method of UAV with stable or weakly stable flying wing layout, and this method relies on the angular rate integrator, the integrator management is difficult, and the timing of controller access will have a great impact on the control effect.

Therefore, in order to solve the above problems, this application proposes a rocket-assisted take-off control method for a flying-wing layout UAV.

Contents of the invention

The object of the present invention is to provide a rocket-assisted launch and take-off control method for a flying-wing UAV, which is used to control the launch and take-off process of a flying-wing UAV in a rocket-assisted manner.

The present invention is realized through the following technical solution: a flying-wing layout UAV rocket-assisted launch take-off control method, including the following steps:

In the process of arrow-assisted launch and take-off of the flying-wing UAV, a control method combining elevator preset and pitch angle control is used in the longitudinal controller;

A control method combining roll angle and damping is used in the lateral controller;

Design sideslip angle stabilization control in the heading controller, and introduce a stabilization softening factor;

Through the combined control of the longitudinal controller, lateral controller and heading controller, the stable access of the stability control of the flying wing UAV is ensured.

In order to better implement the present invention, further, the control method using a combination of elevator preset and pitch angle control for the longitudinal controller includes:

The elevator preset is added to assist the pitch angle control. The elevator preset is used as the feedforward amount of the control. The elevator preset is used to provide a rudder feedforward value that suppresses the disturbance of the flying wing layout UAV.

In order to better implement the present invention, further, the method of using a combination of roll angle and damping control for the lateral controller includes:

The lateral controller uses a roll angle to control the wing level of the flying-wing layout UAV, and sets the roll angle to 0° during the launch and take-off process of the flying-wing layout UAV. After the flying-wing layout UAV reaches a safe height, it Use track mode.

In order to better realize the present invention, further, the method of designing sideslip angle stabilization control for the heading controller and introducing the stabilization softening factor includes:

The sideslip angle is introduced into the heading controller for stability control, and a stabilization softening factor based on surface speed is introduced to ensure that the heading stability is smoothly connected in the high-speed section.

In order to better implement the present invention, further, the formula for calculating the longitudinal controller is:

θ _g =θ ₀

为俯仰角比例控制系数，

为俯仰角速率阻尼控制系数。 Among them, θ ₀ is the angle between the aircraft axis and the ground, θ _g is the pitch angle given, δ _e0 is the elevator preset control surface, q is the pitch angle rate, θ is the pitch angle of the aircraft,

is the pitch angle proportional control coefficient,

is the pitch angle rate damping control coefficient.

In order to better implement the present invention, further, the formula for calculating the lateral controller is:

φ _g =0

数，

为滚转速率阻尼控制系数。 Among them, φ is the roll angle, φ _g is the given roll angle, p roll angle rate,

number,

is the roll rate damping control coefficient.

In order to better implement the present invention, further, the calculation formula for the heading controller is:

为滚转角控制系数，

为航向角控制系数，

为侧滑角增稳控制系数，K _v为侧滑角增稳软化因子。 Among them, φ is the roll angle, r is the roll angle rate given, β is the sideslip angle,

is the roll angle control coefficient,

is the heading angle control coefficient,

is the sideslip angle stabilization control coefficient, and K _v is the sideslip angle stabilization and softening factor.

In order to better realize the present invention, further, the design method of the sideslip angle stabilization and softening factor K _v in the heading controller includes:

Among them, V _ias is the indicated airspeed, V ₁ is the speed at which the selected stabilization starts to be connected, and V ₂ is the speed at which the selected stabilization is fully connected.

Compared with the existing technology, the present invention has the following advantages and beneficial effects:

(1) In the present invention, the longitudinal controller adopts a combination of elevator preset and attitude angle control, and uses the torque generated by the elevator preset and the damping term of the pitch angle rate in the attitude angle control to effectively suppress unfavorable disturbances during the launch and take-off process. Improve the system’s rapid response capability;

(2) The present invention designs a speed-based stabilization and softening factor for the sideslip angle for the lateral direction stabilization control of the flying-wing layout UAV, which can avoid the problems caused by the inaccurate measurement of the sideslip angle during the low-speed section of launch and take-off and the introduction of heading control. Unfavorable disturbances can also ensure that the UAV can smoothly access the sideslip angle stabilization controller during the high-speed section of launch and take-off.

Description of the drawings

The present invention will be further described with reference to the following drawings and examples. All innovative ideas and innovations of the present invention shall be regarded as the disclosed content and the protection scope of the present invention.

Figure 1 is a schematic structural diagram of a longitudinal controller in a rocket-assisted launch and take-off control method for a flying-wing layout UAV provided by the present invention.

Figure 2 is a schematic structural diagram of a lateral controller in a rocket-assisted launch takeoff control method for a flying-wing layout UAV provided by the present invention.

Figure 3 is a schematic structural diagram of a heading controller in a rocket-assisted launch takeoff control method for a flying-wing layout UAV provided by the present invention.

Figure 4 is a flow chart of a rocket-assisted launch and take-off control method for a flying-wing layout UAV provided by the present invention.

Detailed ways

In order to explain the technical solutions in the embodiments of the present invention more clearly, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be understood that the described embodiments are only Some of the embodiments of the present invention are not all embodiments, and therefore should not be regarded as limiting the scope of protection. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

In the description of the present invention, it should be noted that, unless otherwise clearly stated and limited, the terms "set", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. Connection, or integral connection; it can be a mechanical connection or an electrical connection; it can also be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

Example 1:

This embodiment is a rocket-assisted launch and take-off control method for a flying-wing UAV. As shown in Figure 4, this embodiment provides a rocket-assisted launch and take-off control method for a flying-wing UAV. This method is aimed at the launch and take-off process of a flying-wing layout UAV. A control method combining elevator preset and pitch angle control is used longitudinally to slow down the dynamics of the launch boost phase; roll angle control is used laterally to keep the wings flat and climb to a safe height. The tracking track and heading design are based on speed-based stabilization and softening factors to avoid adverse disturbances caused by the rudder caused by low-speed sideslip angle stabilization, and to ensure that the UAV can achieve normal stability control in the air.

Example 2:

This embodiment is further optimized on the basis of Embodiment 1. In this embodiment, a control method combining pitch angle control is used for the longitudinal controller, and the elevator preset auxiliary pitch angle control is added, and the elevator preset is used as the control front The amount of feedback can effectively slow down the dynamics of the aircraft when the rocket breaks away from the launch boost stage. The main task of longitudinal control is to keep the drone's longitudinal states stable during the launch process. The longitudinal states include: pitch angle, angle of attack, altitude, lifting speed, etc. The elevator preset is used to provide a rudder feedforward value that suppresses UAV disturbance. This value can be selected according to the actual aircraft characteristics. The damping term of the pitch angle rate is used to dampen the disturbance during launch and take-off to ensure a smooth launch process. .

The other parts of this embodiment are the same as those of Embodiment 1, so they will not be described again.

Example 3:

This embodiment is further optimized on the basis of the above-mentioned Embodiment 1 or 2. In this embodiment, the lateral controller uses the roll angle to control the plane of the aircraft wing. After reaching a safe height, the tracking mode is used to control the lateral heading. The main task of the UAV is to control the wing level of the UAV. The roll angle is given as 0° during the launch and take-off process, and the side slip angle is introduced to stabilize the heading. This solves the problem of insufficient heading stability of the UAV with a flying wing layout. The design is based on surface speed. The stabilization softening factor ensures the smooth access of the heading stabilization in the high-speed section.

The other parts of this embodiment are the same as those of the above-mentioned Embodiment 1 or 2, so they will not be described again.

Example 4:

This embodiment is further optimized based on any one of the above-mentioned Embodiments 1-3. In this embodiment, the heading controller adopts sideslip angle stabilization control, and the sideslip angle stabilization access adopts speed-based augmentation. Stabilize the softening factor to solve the problem of insufficient directional stability of the flying-wing UAV, avoid the adverse disturbance caused by inaccurate measurement of sideslip angle in the low-speed section of launch and take-off, and ensure the UAV in the high-speed section of launch and take-off. Smooth access to the sideslip angle stabilization controller.

The other parts of this embodiment are the same as any one of the above-mentioned Embodiments 1-3, and therefore will not be described again.

Example 5:

This embodiment is further optimized based on any one of the above-mentioned Embodiments 1-4. In this embodiment, the main task of longitudinal control is to keep the various longitudinal states of the UAV stable during the launch process. The longitudinal states include : Pitch angle, angle of attack, altitude, lifting speed, etc. The elevator preset is used to provide a rudder feedforward value that suppresses UAV disturbance. This value can be selected according to the actual aircraft characteristics. The damping term of the pitch angle rate is used to dampen the disturbance during launch and take-off to ensure a smooth launch process. .

As shown in Figure 2, the longitudinal control law structure is shown, and its control law is:

θ _g =θ ₀ , equation (2);

为俯仰角比例控制系数，控制参数

为俯仰角速率阻尼控制系数，θ ₀为飞机轴线与地面的夹角，θ _g为俯仰角给定，δ _e0为升降舵预置值。 Control parameters

is the pitch angle proportional control coefficient, control parameter

is the pitch angle rate damping control coefficient, θ ₀ is the angle between the aircraft axis and the ground, θ _g is the pitch angle given, and δ _e0 is the elevator preset value.

Formula (1) gives the pitch angle (θ _g ), and calculates the elevator control signal (δ _e ) to the elevator servo actuator, thereby controlling the elevator to control the pitching moment of the aircraft, thereby achieving longitudinal control during the launch and takeoff process.

The other parts of this embodiment are the same as any one of the above-mentioned Embodiments 1-4, and therefore will not be described again.

Example 6:

This embodiment is further optimized based on any one of the above-mentioned embodiments 1-5. In this embodiment, the main task of lateral heading control is to control the wing level of the UAV. The roll angle during launch and take-off is given as 0°. The sideslip angle stabilization is introduced in the heading to solve the problem of insufficient heading stability of the flying-wing UAV. A stabilization softening factor based on surface speed is designed to ensure the smooth access of the heading stabilization in the high-speed section.

Figure 2 shows the lateral controller structure, and its control law is:

φ _g =0, formula (4);

为比例控制系数，

为比例控制系数,跟踪公式(3)滚转角给定目标值φ _g，解算出副翼控制信号δ _a，发送给副翼执行结构，控制无人机保持发射过程翼平。 Control parameters

is the proportional control coefficient,

is the proportional control coefficient, tracking the target value φ _g of the roll angle in formula (3), and calculating the aileron control signal δ _a , which is sent to the aileron execution structure to control the UAV to keep the wings level during the launch process.

The other parts of this embodiment are the same as any one of the above-mentioned Embodiments 1-5, and therefore will not be described again.

Example 7:

This embodiment is further optimized based on any one of the above-mentioned embodiments 1-6, as shown in Figure 3, which is a schematic structural diagram of the heading controller, and its control law is:

Mode;

为侧滑角增稳比例控制系数，控制参数

为航向角比例控制系数，控制参数

为航向滚转通道比例控制系数，控制参数K _v为侧滑角增稳软化因子，V _G为地速； Control parameters

Stabilization proportional control coefficient for sideslip angle, control parameter

is the heading angle proportional control coefficient, control parameter

is the heading and roll channel proportional control coefficient, the control parameter K _v is the sideslip angle stabilization and softening factor, and V _G is the ground speed;

Substituting the surface speed V _ias into the formula (6), the sideslip angle stabilization and softening factor is obtained. Substituting the formula (6) into the formula (5), the rudder control signal formula δ _r is solved and sent to the rudder execution structure to ensure unmanned operation. The stability of the aircraft during launch and take-off.

The other parts of this embodiment are the same as any one of the above-mentioned Embodiments 1-6, and therefore will not be described again.

The above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention fall within the scope of the present invention. within the scope of protection.

Claims (8)

A rocket-assisted launch and take-off control method for a flying-wing UAV, which is characterized by including the following steps: during the arrow-assisted launch and take-off process of a flying-wing UAV, using elevator preset and A control method that combines pitch angle control; a control method that combines roll angle and damping is used in the lateral controller; a sideslip angle stabilization control is designed in the heading controller, and a stabilization softening factor is introduced; through the longitudinal controller, The combined control of the lateral controller and the heading controller ensures smooth access to the stability control of the flying-wing UAV. A rocket-assisted launch and take-off control method for a flying-wing layout UAV according to claim 1, characterized in that the control method combining elevator preset and pitch angle control includes: The elevator preset is added to assist the pitch angle control. The elevator preset is used as the feedforward amount of the control. The elevator preset is used to provide a rudder feedforward value that suppresses the disturbance of the flying wing layout UAV. A flying-wing layout UAV rocket-assisted launch take-off control method according to claim 1, characterized in that the method of using a combination of roll angle and damping for the lateral controller includes: using a roll for the lateral controller The rotation angle controls the wing plane of the flying-wing layout UAV, and the roll angle is set to 0° during the launch and take-off process of the flying-wing layout UAV. After the flying-wing layout UAV reaches a safe height, the tracking mode is used. . A flying-wing layout UAV rocket-assisted launch take-off control method according to claim 1, characterized in that the method of designing sideslip angle stabilization control for the heading controller and introducing a stabilization softening factor includes: The sideslip angle is introduced into the heading controller for stability control, and a stability softening factor based on surface speed is introduced to ensure that the heading stability is smoothly connected in the high-speed section. A flying-wing layout UAV rocket-assisted launch takeoff control method according to any one of claims 1 or 2, characterized in that it includes:

The formula for calculating the longitudinal controller is: θ _g = θ ₀ ; where δ _e is the elevator control signal, θ ₀ is the angle between the aircraft axis and the ground, θ _g is the pitch angle given, and δ _e0 is the elevator preset Set the rudder surface, q is the pitch angle rate, θ is the pitch angle of the aircraft,

is the pitch angle proportional control coefficient,

is the pitch angle rate damping control coefficient. A flying-wing layout UAV rocket-assisted launch takeoff control method according to any one of claims 1 or 3, characterized in that it includes:

The formula for calculating the lateral controller is: φ _g = 0; where δ _a is the aileron control signal, φ is the roll angle, φ _g is the given roll angle, p roll angle rate,

is the roll angle proportional control coefficient,

is the roll rate damping control coefficient. A flying-wing layout UAV rocket-assisted launch takeoff control method according to any one of claims 1 or 4, characterized in that it includes: The calculation formula for the heading controller is:

Among them, δ _r is the rudder heading control signal, φ is the roll angle, r is the roll angle rate given, β is the sideslip angle,

is the roll angle control coefficient,

is the heading angle control coefficient,

is the sideslip angle stabilization control coefficient, and K _v is the sideslip angle stabilization and softening factor. A flying-wing layout UAV rocket-assisted launch take-off control method according to claim 7, characterized in that the design method of the sideslip angle stabilizing and softening factor K _v in the heading controller includes:

Among them, V _G is the ground speed, V _ias is the indicated airspeed, V ₁ is the speed at which the selected stabilization starts to be connected, and V ₂ is the speed at which the selected stabilization is fully connected.

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