Aircraft rapid guidance control method with momentum device as actuator
By using momentum devices as actuators in low-speed aircraft and using the angular momentum principle for maneuver control, the problem of inefficiency of air rudders during low-speed flight or large overload maneuvering is solved, efficient and precise control is achieved, and the impact on aerodynamic envelopes and design costs are reduced.
Patent Information
- Application Number
- CN202411773801.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-05
- Publication Date
- 2025-03-04
AI Technical Summary
In the prior art, when a small, light and small fixed-wing aircraft flying at low speed is controlled by an air rudder, the control efficiency is low and the accuracy is poor. Especially when maneuvering at low speed or large overload, the efficiency of the air rudder is greatly reduced and effective control cannot be provided.
The momentum device is used as the actuator, and the maneuver control is performed through the angular momentum principle, and the control torque command of the momentum device is designed to ensure that the attitude angle tensor during the attitude adjustment process is in the target attitude adjustment tensor plane and follows the angular velocity of the target state trajectory.
It realizes efficient control during low-speed flight or large overload maneuvering, with faster response speed and higher accuracy, with almost no impact on the aerodynamic envelope of the entire machine, reducing design and production costs.
Smart Images
Figure CN119556715A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of guidance control, and in particular to a method for rapid guidance control of an aircraft using a momentum device as an actuator. Background Art
[0002] Light and small aircraft flying at low speeds, including some drones, missiles, cruise missiles, etc., use aerodynamics to fly in the atmosphere.
[0003] Currently, fixed-wing aircraft generally use air rudders as actuators, using the rudder blades to disturb the airflow to form aerodynamic torque, change the aircraft attitude, and then achieve closed-loop center of mass control. Although the air rudder technology is very mature, because it uses aerodynamic effects to provide control, its flight speed cannot be too low, otherwise the control efficiency of the air rudder will be greatly reduced.
[0004] Generally speaking, when the flight speed is lower than 0.3 Mach, the aerodynamic torque that the air rudder can provide is extremely limited. In addition, when the angle of attack is too large, the efficiency of the rudder surface drops significantly, and even when the angle of attack exceeds 20°, the efficiency of the rudder surface is almost completely lost. Therefore, the air rudder is not suitable for large-scale maneuvering control, especially for light and small aircraft flying at low speeds. The control efficiency and accuracy of the air rudder are low. Summary of the invention
[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for rapid aircraft guidance and control using a momentum device as an actuator, which is used for rapid attitude adjustment and stabilization of fixed-wing aircraft / rotorcraft flying at low speed to achieve guidance. It has faster response speed and higher precision, has almost no effect on the aerodynamic envelope of the entire aircraft, and always maintains efficient control when the aircraft is flying at low speed or maneuvering with high overload.
[0006] In order to achieve the purpose of the present invention, the following scheme is proposed: A method for rapid guidance and control of an aircraft using a momentum device as an actuator comprises the following steps: S100. Estimate the required angular momentum based on the expected flight time and mission requirements using the following formula: In the formula, L n is the required angular momentum, k is the margin coefficient, k ≥1, T is the expected mission flight time, M is the instantaneous torque, || M|| represents the generalized norm; S200, selecting a momentum device according to the estimated required angular momentum, the maximum required torque in the flight mission, and the control accuracy requirement; S300, designing a guidance law according to the characteristics of the flight mission, adopting a state trajectory planning method, and determining a target state trajectory with the maneuverability of the selected momentum device as a constraint; S400. Set the angular velocity as the target state variable, take the maneuverability of the selected momentum device as a constraint, and directly design the control torque instructions of each installation channel of the momentum device based on the linear relationship between the control torque formed by the momentum device and the synthesized resultant torque as shown by the angular momentum principle, so as to ensure that the attitude angle tensor in the attitude adjustment process is always in the target attitude adjustment tensor plane and always follows the angular velocity that adapts the target state trajectory.
[0007] Among them, the selected momentum device is at least one of an inertia wheel, a control moment gyro CMG, a frame-type momentum wheel, and a momentum ball. The inertia wheel is a reaction wheel with an average momentum of 0 or a momentum wheel with an average momentum of a non-zero constant. The control moment gyro CMG is a set of single-frame control moment gyro CMG or a set of double-frame control moment gyro CMG. The frame-type momentum wheel is a single-frame momentum wheel or a double-frame momentum wheel.
[0008] Further, step S400 specifically includes: S410, setting the angular velocity as the target state variable, taking the maneuverability of the selected momentum device as a constraint, and planning an angular velocity adjustment and maintenance curve that matches the target state trajectory; S420, according to the linear relationship between the resultant torque of the target state trajectory indicated by the angular momentum principle and the control torque that can be provided by the selected momentum device, directly solve the control torque according to the angular velocity adjustment and maintenance curve; S430. According to the installation method of the selected momentum device, the solved control torque is decomposed into the installation channels corresponding to the components in the selected momentum device to form control torque instructions for each installation channel, so as to ensure that the attitude angle tensor in the attitude adjustment process is always in the target attitude adjustment tensor plane and always follows the angular velocity of the adapted target state trajectory.
[0009] Furthermore, the aircraft is a fixed-wing aircraft or a rotorcraft.
[0010] The beneficial effects of the present invention are: 1. The present invention uses a momentum device as an actuator for a low-speed, light and small fixed-wing aircraft. The actuator is completely inside the aerodynamic envelope and uses the principle of angular momentum for maneuvering control. The entire flight process will not change the overall aerodynamic envelope, and the influence of the maneuvering method using an air rudder or thrust vector mechanism on the aerodynamic envelope and the influence of the hinge torque of the air rudder are completely eliminated. The advantage of not affecting the aerodynamic envelope of the entire aircraft is that when the aerodynamic angle changes, the aerodynamic force can be directly obtained by looking up the table and interpolating, without the need to calculate complex local corrections (greatly reducing the amount of onboard calculations), and there is no need to perform additional simulations or tests for local corrections (shortening the design cycle and improving the reusability and inheritance of the same model of aircraft scale-down or scale-up). This improves the reliability of scale-down and reuse of the same type of aerodynamic structure from a design level, while reducing the difficulty of control system design for such low-speed, light and small fixed-wing aircraft; furthermore, if the solution of the present invention is used for large-scale production of such aircraft, it will greatly reduce the design, testing and production costs; 2. Compared with the method of using pneumatic rudder for control, the control method of the present invention uses the momentum device as the actuator. The control process of the present invention has a shallow nesting depth and high resolution, so the response speed is faster and the accuracy is higher. The scheme of the present invention greatly improves the control accuracy and response speed at the software algorithm and hardware mechanism level, ensuring that the guidance control is more accurate and faster; further, even in low-speed and high-overload maneuvers, there is no problem of reduced aerodynamic efficiency of the rudder surface, thereby fundamentally avoiding the problem of reduced control efficiency of the air rudder or even failure to provide control; 3. For rotorcraft, the present invention uses a momentum device as an actuator to bypass the problem of overlap between the power surface and the control surface, directly adjust the attitude of the drone from the inside, avoids dynamic difficulties such as nonlinear coupling, underactuation, and multivariables, improves control stability, and simplifies the control mechanism; 4. The momentum device can be completely inside the aircraft, and there is no necessary motion mechanism device outside the aircraft, which can better carry out the overall airtight, watertight and stealth design; and the momentum device can be located at any position inside the aircraft, and the required power of the actuator can be greatly reduced by configuring the installation position and installation method of the momentum device, thereby optimizing the energy demand of the control system. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 The present invention is a schematic diagram of the aircraft guidance control process using a pneumatic rudder as an actuator in the prior art.
[0012] Figure 2 This is a schematic diagram of the aircraft guidance control process using a momentum device as an actuator in an embodiment of the present application.
[0013] Figure 3 This is a flowchart of the control method steps of an embodiment of the present application.
[0014] Figure 4 It is a schematic diagram of a trapezoidal angular velocity adjustment and maintenance curve according to an embodiment of the present application.
[0015] Figure 5 Schematic diagram of a cosine-shaped angular velocity adjustment and maintenance curve according to an embodiment of the present application. DETAILED DESCRIPTION
[0016] like Figure 1 The figure shows the prior art aircraft guidance control process using pneumatic rudder as actuator. Figure 1 In the example of the pitch maneuver in the longitudinal symmetry plane, the expected result of the guidance process is the coordinate position of the center of mass (in addition, acceleration, line of sight angular displacement and other observables can usually be selected as the expected result of the guidance process, which can be flexibly handled according to the specific situation). The lateral control can refer to this example and be handled according to the common practice in the industry, which will not be repeated here. y t represents the expected center of mass of the vehicle y coordinates, is the expected result after the guidance is realized; ∆ y Indicates the center of mass position deviation y Directional weight; δ zc Indicates the elevator deflection angle command; δ z Indicates the elevator deflection angle; Indicates the control force of the rudder surface; represents the steering torque; ω z express z Directional angular velocity component, the dot on any symbol indicates the time derivative of it, and the number of dots indicates the number of derivatives; ϑ Indicates the pitch angle; α represents the angle of attack; F y represents the normal force; f y represents the normal acceleration; θ Indicates the ballistic inclination angle; y m The actual center of mass of the aircraft y coordinate.
[0017] The specific process is as follows: the difference between the expected coordinates and the actual coordinates of the center of mass of the aircraft is used as the control input, and an appropriate control algorithm is used to calculate the rudder deflection command. The rudder deflection command is input into the air rudder, and the actual rudder deflection angle is obtained by execution, which disturbs the airflow and obtains the rudder surface control force. The rudder surface control force forms the rudder control torque and determines the angular acceleration in the pitch direction. After two time integrations, the pitch angle that changes with the control is obtained. After the pitch angle changes, the angle with the incoming flow direction, that is, the angle of attack, changes, and changes the normal vector force. At the same time, the rudder surface control force itself also makes a small contribution to the change of the normal force. The normal forces from the two sources are combined to change the normal acceleration, which then acts on the change in the angular velocity of the ballistic inclination angle. The ballistic inclination angle is changed after time integration, thereby changing the actual coordinates of the center of mass of the aircraft.
[0018] In the above process, the process of obtaining the rudder control force by the rudder deflection angle disturbing the airflow depends on the aerodynamic parameters. The rudder control force has complex aerodynamic effects and system dynamics due to the processes of "forming control torque and then changing the normal acceleration" and "directly changing the normal acceleration". Therefore, the control algorithm for calculating the rudder deflection command has a relatively large amount of calculation.
[0019] In this example, a momentum device is selected as the actuator. The momentum device uses a control torque gyro, a momentum wheel, a flywheel, etc. Figure 2 The aircraft guidance and control process shown in FIG. p t represents the expected coordinates of the center of mass of the aircraft, which is the expected result after the guidance is achieved; ∆ p represents the deviation of the center of mass position; M Mc Indicates the control torque command; M Mc,i Represents the control torque command of each channel, where the subscript i The momentum device i Installation channels; M M represents the achieved control torque; ω represents angular velocity; Ω Represents the Euler angle, which can be further decomposed into roll angle, yaw angle, and pitch angle; α K Indicates the aerodynamic angle; F Indicates aerodynamic force; f represents acceleration; Θ It represents the ballistic angle, which can be further decomposed into velocity tilt angle, ballistic deviation angle, and ballistic inclination angle; p m Indicates the actual coordinates of the vehicle's center of mass.
[0020] The specific process is as follows: the difference between the expected coordinates and the actual coordinates of the center of mass of the aircraft is used as the control input, and an appropriate control algorithm is used to calculate the control torque command, which is distributed to each installation channel to form a channel command input momentum device, and the actual control torque is obtained by execution. The torque applied to the system determines the angular acceleration, and after two time integrations, the Euler angle that changes with the control is obtained, thereby changing the angle with the incoming flow direction, changing the aerodynamic force, forming an acceleration change, and then acting on the angular velocity change of the ballistic angle. The ballistic angle is changed after time integration, thereby changing the actual coordinates of the center of mass of the aircraft.
[0021] Compared with the traditional method of using pneumatic rudders as actuators, the method of using momentum devices as actuators compresses the nesting depth of the guidance control loop, simplifies the process of the rudder surface aerodynamic force forming aerodynamic torque, avoids the cross-coupling effect of the rudder surface aerodynamic force on the overall aerodynamic force, and can directly adjust the attitude.
[0022] Since the angular momentum distribution between the target angular momentum and the actuator controlled angular momentum has a linear characteristic, the general control method using the momentum device as the actuator can directly design the target angular momentum state trajectory. Specifically for the application of this method in low-speed, light and small fixed-wing aircraft, there are some application points that need special attention in each step.
[0023] Specifically, the present application provides a method for rapid guidance and control of an aircraft using a momentum device as an actuator, which is suitable for low-speed, large-amplitude maneuvering aircraft, such as fixed-wing aircraft, such as Figure 3 As shown, the control method includes the steps of: S100. Estimate the required angular momentum based on the expected flight time and mission requirements. Since fixed-wing aircraft and other aircraft fly in the atmosphere, the damping effect of aerodynamic drag on the aircraft should be considered, and a certain margin should be left for the "required angular momentum". Preferably, some generalized norm operation can be performed on the angular momentum during the expected mission to obtain the upper (confirm) bound as a reference for the required angular momentum. Use the following formula: In the formula, L n is the required angular momentum, k is the margin coefficient, k ≥1, preferably, k is 1.15, T is the expected mission flight time, M is the instantaneous torque, || M|| It represents the generalized norm, which is usually 2-norm. You can also use 1-norm or infinite norm according to design requirements or task characteristics.
[0024] S200, selecting a momentum device according to the estimated required angular momentum, the maximum required torque in the flight mission, and the control accuracy requirements.
[0025] Among them, the selected momentum device is at least one of an inertia wheel, a control moment gyro CMG, a frame-type momentum wheel, and a momentum ball. The inertia wheel is a reaction wheel with an average momentum of 0 or a momentum wheel with an average momentum of a non-zero constant. The control moment gyro CMG is a set of single-frame control moment gyro CMG or a set of double-frame control moment gyro CMG. The frame-type momentum wheel is a single-frame momentum wheel or a double-frame momentum wheel.
[0026] Optionally, the specific installation method of the momentum device matches its structural characteristics and the way of generating control. Commonly used devices and their installation methods mainly include: a reaction wheel with three-axis orthogonal installation, or a zero momentum system consisting of four offset momentum wheels with three-axis orthogonal installation and a fourth equal-inclination oblique installation, or a fixed installation or V-shaped oblique installation offset momentum wheel system, or a double-frame momentum wheel, or a control torque gyroscope CMG.
[0027] It should be noted that here, not only the models of the components of the momentum device are selected, but also, because the current low-cost momentum device has an upper limit, for long-term missions, the angular momentum demand may be dissipated. At the end of the mission, the angular momentum pre-installed in the momentum device is dissipated, so that the terminal control cannot be completed. Therefore, it is necessary to select control torque devices that meet the mission requirements, such as gyroscopes, based on the reference required angular momentum, the maximum required torque in the flight mission, and the control accuracy requirements. Note that the quality and power consumption of the device should be paid attention to during the design.
[0028] S300. Design a guidance law according to the characteristics of the flight mission, adopt a state trajectory planning method, and determine the target state trajectory with the maneuverability of the selected momentum device as a constraint.
[0029] Specifically, as attached Figure 1 and attached Figure 2 As shown, this embodiment uses the mass center position deviation closed-loop guidance instruction; other guidance methods can also be used, which will not be described in detail.
[0030] S400, setting the angular velocity as the target state variable, taking the maneuverability of the momentum device as a constraint, and based on the linear relationship between the control torque formed by the momentum device and the synthesized resultant torque as shown by the angular momentum principle, directly design the control torque instructions for each installation channel of the momentum device to ensure that the attitude angle tensor during the attitude adjustment process is always in the target attitude adjustment tensor plane and always follows the angular velocity that adapts to the target state trajectory.
[0031] Specifically, step S400 includes the following steps: S410, setting the angular velocity as the target state variable, taking the maneuverability of the selected momentum device as a constraint, and planning an angular velocity adjustment and maintenance curve that matches the target state trajectory; Optionally, in step S300, the target state trajectory is determined by maneuvering along the minimum path in accordance with the Euler axis-angle method, and the angular velocity adjustment and maintenance curve planned in step S410 is a trapezoid.
[0032] Optionally, in step S300, the target state trajectory is determined by maneuvering along the trajectory of minimum angular acceleration in accordance with the Euler axis-angle method, and the angular velocity adjustment and maintenance curve planned in step S410 is cosine-shaped.
[0033] S420, according to the linear relationship between the resultant torque of the target state trajectory indicated by the angular momentum principle and the control torque that can be provided by the selected momentum device, directly solve the control torque according to the angular velocity adjustment and maintenance curve; S430. According to the installation method of the selected momentum device, the solved control torque is decomposed into the installation channels corresponding to the components in the selected momentum device to form control torque instructions for each installation channel, so as to ensure that the attitude angle tensor in the attitude adjustment process is always in the target attitude adjustment tensor plane and always follows the angular velocity of the adapted target state trajectory.
[0034] At this point, the momentum device performs attitude adjustment and stabilization of the fixed-wing aircraft according to the guidance instructions to complete the guidance and control closed loop.
[0035] The control system established by adopting the solution of this example is low-cost and reusable, and is particularly suitable for reusable UAV systems.
[0036] The method of this example is specifically designed and can be expanded to be applied to rotorcraft, so as to achieve precise and stable control of rotorcraft flying at low speeds and reduce the requirements for the rotor blade control system.
[0037] Compared with the method of using pneumatic rudders for control, the control process of this embodiment has a shallow nesting depth, high resolution, faster response speed and higher accuracy; unlike the air rudder that forms control force by directly interfering with the airflow and the thrust vector mechanism that uses the mass discharge method to change the local flow field, this embodiment uses angular momentum exchange to achieve control, which has almost no effect on the aerodynamic envelope of the entire aircraft; this embodiment also solves the problem of low efficiency or even uncontrollable control of pneumatic rudders when the aircraft is flying at low speed or maneuvering with high overload.
[0038] The above are only preferred embodiments of the present invention, and are not intended to be the only or limiting embodiments of the present invention. Those skilled in the art should understand that various changes or equivalent substitutions made to the present invention without departing from the scope of the present invention are within the scope of protection of the present invention.
Claims
1. A method for rapid guidance and control of an aircraft using a momentum device as an actuator, characterized in that: Includes steps: S100. Estimate the required angular momentum based on the expected flight time and mission requirements using the following formula: In the formula, L n is the required angular momentum, k is the margin coefficient, k ≥1, T is the expected mission flight time, M is the instantaneous torque, || M || represents the generalized norm; S200, selecting a momentum device according to the estimated required angular momentum, the maximum required torque in the flight mission, and the control accuracy requirement; S300, designing a guidance law according to the characteristics of the flight mission, adopting a state trajectory planning method, and determining a target state trajectory with the maneuverability of the selected momentum device as a constraint; S400, setting the angular velocity as the target state variable, taking the maneuverability of the selected momentum device as a constraint, and directly designing the control torque instructions of each installation channel of the momentum device according to the linear relationship between the control torque formed by the momentum device and the synthesized resultant torque as shown by the angular momentum principle, so as to ensure that the attitude angle tensor in the attitude adjustment process is always in the target attitude adjustment tensor plane and always follows the angular velocity of the adapted target state trajectory; Among them, the selected momentum device is at least one of an inertia wheel, a control moment gyro CMG, a frame-type momentum wheel, and a momentum ball. The inertia wheel is a reaction wheel with an average momentum of 0 or a momentum wheel with an average momentum of a non-zero constant. The control moment gyro CMG is a set of single-frame control moment gyro CMG or a set of double-frame control moment gyro CMG. The frame-type momentum wheel is a single-frame momentum wheel or a double-frame momentum wheel.
2. The method for rapid guidance and control of an aircraft using a momentum device as an actuator according to claim 1, characterized in that: The momentum device selected is a reaction wheel with three axes orthogonally mounted, or a zero momentum system consisting of four offset momentum wheels with three axes orthogonally mounted and a fourth equal-inclination angle mounted obliquely, or an offset momentum wheel system with fixed mounting or V-shaped oblique mounting, or a double-frame momentum wheel, or a control moment gyro CMG.
3. The method for rapid guidance and control of an aircraft using a momentum device as an actuator according to claim 1, characterized in that: || M|| Take the 2-norm, 1-norm, or infinity-norm.
4. The method for rapid guidance and control of an aircraft using a momentum device as an actuator according to claim 1, characterized in that: Step S400 includes: S410, setting the angular velocity as the target state variable, taking the maneuverability of the selected momentum device as a constraint, and planning an angular velocity adjustment and maintenance curve that matches the target state trajectory; S420, according to the linear relationship between the resultant torque of the target state trajectory indicated by the angular momentum principle and the control torque that can be provided by the selected momentum device, directly solve the control torque according to the angular velocity adjustment and maintenance curve; S430. According to the installation method of the selected momentum device, the solved control torque is decomposed into the installation channels corresponding to the components in the selected momentum device to form control torque instructions for each installation channel, so as to ensure that the attitude angle tensor in the attitude adjustment process is always in the target attitude adjustment tensor plane and always follows the angular velocity of the adapted target state trajectory.
5. The method for rapid guidance and control of an aircraft using a momentum device as an actuator according to claim 4, characterized in that: In step S300, the target state trajectory is determined by maneuvering along the minimum path in the Euler axis-angle method, and the angular velocity adjustment and maintenance curve planned in step S410 is a trapezoid.
6. The method for rapid guidance and control of an aircraft using a momentum device as an actuator according to claim 4, characterized in that: In step S300, the target state trajectory is determined by adopting the Euler axis-angle method and the trajectory of the minimum angular acceleration maneuver. In step S410, the angular velocity adjustment and maintenance curve planned is a cosine shape.
7. The method for rapid guidance and control of an aircraft using a momentum device as an actuator according to claim 1, characterized in that: The aircraft is a fixed-wing aircraft.
8. The method for rapid guidance and control of an aircraft using a momentum device as an actuator according to claim 1, characterized in that: The aircraft is a rotorcraft.