Method for stably controlling deformation process of unmanned aerial vehicle in complex environment

Abstract

The invention discloses a stable control method for a deformation process of an unmanned aerial vehicle in a complex environment, and relates to the technical field of unmanned aerial vehicle flight control. The state-space equation is used for describing flight dynamics parameters in the deformation process of the unmanned aerial vehicle in the complex environment; constructing a disturbance observer based on the state-space equation; the disturbance observer is used for observing a lumped disturbance quantity caused by a complex environment and wing tip folding deformation; constructing a sliding mode surface equation according to the attitude angle tracking error; constructing an attitude stability controller according to the disturbance observer and the sliding mode surface equation; and based on the Lyapunov stability theory, performing stable control on the unmanned aerial vehicle by using an attitude stability controller. The lumped disturbance quantity caused by the complex environment and wing tip folding deformation is considered during flight control of the unmanned aerial vehicle, and the control precision of the deformable unmanned aerial vehicle under the complex environment condition can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of unmanned aerial vehicle flight control, and in particular to a method for stabilizing the deformation process of an unmanned aerial vehicle in a complex environment. Background Art

[0002] In recent years, with the rapid development of UAV technology, UAVs have been increasingly used in civil and military fields, especially in industries such as aviation, logistics, agriculture, and environmental monitoring. They have become an indispensable key carrier. However, with the continuous expansion of UAV functions, the complexity of their flight environment and missions is also increasing. In some special missions, UAVs need to undergo structural deformation (such as wingtip folding or wing extension) to adapt to mission requirements or environmental restrictions. The disturbances caused by the deformation process undoubtedly increase the difficulty of UAV attitude and stability control. In addition, complex environmental disturbances such as gusts or turbulence also have a significant impact on the flight control and deformation stability of UAVs.

[0003] At present, there have been some studies on the anti-interference control of UAV deformation, which mainly focuses on ensuring the stability of UAV through traditional control algorithms (such as PID control or LQR control, etc.). However, these methods still have certain limitations when facing rapidly changing flight environments and large structural deformations. Traditional attitude control methods have poor adaptability to external disturbances and it is difficult to effectively deal with the nonlinear characteristics in the system. In addition, existing control methods usually lack accurate estimation and compensation of disturbances during deformation, resulting in the attitude control accuracy of UAVs in complex environments being difficult to meet the requirements of high-precision flight missions. Therefore, studying the stable control method of UAVs during deformation in complex environments is of great significance to the further technological development and progress of UAVs. Summary of the invention

[0004] The purpose of this application is to provide a method for stabilizing the deformation process of a UAV in a complex environment, which can improve the control accuracy of a deformable UAV under complex environmental conditions.

[0005] To achieve the above purpose, the present application provides the following solution: The present application provides a method for stable control of deformation process of a UAV in a complex environment, including: constructing a state space equation. The state space equation is used to describe the flight dynamics parameters of the UAV during deformation in a complex environment.

[0006] Based on the state space equation, a disturbance observer is constructed, which is used to observe the lumped disturbance caused by the complex environment and the wing tip folding deformation.

[0007] According to the expected attitude angle, the attitude angle tracking error is determined.

[0008] According to the attitude angle tracking error, the sliding surface equation is constructed.

[0009] According to the disturbance observer and the sliding surface equation, an attitude stabilization controller is constructed.

[0010] Based on Lyapunov stability theory, the attitude stabilization controller is used to stabilize the UAV.

[0011] Optionally, after constructing the sliding surface equation according to the attitude angle tracking error, the method further includes: The sliding surface equation is differentiated to obtain a differentiated sliding surface equation.

[0012] Optionally, the state space equation is: .

[0013] in, Represents the drone attitude angle variable The derivative of . Represents the attitude angular velocity variable The derivative of . and Both represent the structural quantity of the UAV system. Represents the control quantity of the UAV system. Represents the total disturbance caused by the complex environment and the wingtip folding deformation.

[0014] Optionally, the disturbance observer is: .

[0015] .

[0016] in, Represents the estimator of the drone's attitude angle variable The derivative of . An estimate of the total disturbance caused by the complex environment and the wing tip folding deformation The derivative of . are disturbance observer parameters, , . and Both represent the observer structural equation. Both represent custom parameters. , . Represents a symbolic function.

[0017] Optionally, the constraints of the disturbance observer are: .

[0018] in, is a minimum positive value.

[0019] Optionally, the sliding surface equation is: .

[0020] in, Represents the sliding surface. Both represent sliding surface parameters. represents the attitude angle tracking error, , represents the desired attitude angle.

[0021] Optionally, the sliding surface equation after derivative is: .

[0022] in, represents the sliding surface after differentiation. Represents the attitude angle tracking error after differentiation.

[0023] Optionally, the attitude stabilization controller is: .

[0024] in, All represent controller parameters. .

[0025] According to the specific embodiments provided in this application, this application discloses the following technical effects: The present application provides a stable control method for the deformation process of a UAV in a complex environment. First, by designing a disturbance observer and combining a sliding mode control method, the influence of complex environmental disturbances and deformation disturbances can be effectively estimated and compensated, ensuring that the UAV always maintains a stable attitude during structural deformations such as wingtip folding; the stability criterion of the Lyapunov method is adopted to prove that the control method of the present application can ensure the stability of the system; secondly, the control method of the present application has high adaptability and can be dynamically adjusted for different complex environmental disturbances to ensure that flight stability can be maintained in various flight missions. At the same time, by reasonably designing a sliding mode controller, the control system converges quickly, and the attitude stability of the UAV can be restored in a short time to meet the needs of rapid response. Compared with traditional control methods, the present application can show superior performance when dealing with the disturbance problem caused by wingtip folding deformation. Traditional methods are often difficult to cope with these challenges, and may even cause attitude instability. The control method of the present application effectively avoids this problem and can ensure that the UAV can still fly stably when the wingtip folding deformation is performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a flow chart of a method for stabilizing the deformation process of a UAV in a complex environment in one embodiment of the present application.

[0028] Figure 2 This is a schematic diagram of a method for stabilizing the deformation process of a UAV in a complex environment in one embodiment of the present application. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0031] In an exemplary embodiment, Figure 1 As shown, a method for stable control of deformation process of a UAV in a complex environment is provided, including: Step 101: constructing a state space equation. The state space equation is used to describe the flight dynamics parameters of the UAV during deformation in a complex environment. The state space equation is: .

[0032] in, Represents the drone attitude angle variable The derivative of . Represents the attitude angular velocity variable The derivative of . and Both represent the structural quantity of the UAV system. Represents the control quantity of the UAV system. Represents the total disturbance caused by the complex environment and the wingtip folding deformation.

[0033] Step 102: Construct a disturbance observer based on the state space equation.

[0034] The disturbance observer is used to observe the total disturbance caused by the complex environment and the wing tip folding deformation. The disturbance observer is: .

[0035] .

[0036] in, Represents the estimator of the drone's attitude angle variable The derivative of . An estimate of the total disturbance caused by the complex environment and the wing tip folding deformation The derivative of . are disturbance observer parameters, , . and Both represent the observer structural equation. Both represent custom parameters. , . Represents a symbolic function.

[0037] The constraints of the disturbance observer are: .

[0038] in, is a minimum positive value.

[0039] Step 103: Determine the attitude angle tracking error according to the expected attitude angle.

[0040] Step 104: Construct a sliding surface equation according to the attitude angle tracking error.

[0041] Based on the sliding mode method, the sliding surface is designed to achieve the overall stable control of the UAV.

[0042] The sliding surface equation is: .

[0043] in, Represents the sliding surface. Both represent sliding surface parameters. represents the attitude angle tracking error, , represents the desired attitude angle.

[0044] The sliding surface equation is differentiated (with respect to time) to obtain the differentiated sliding surface equation.

[0045] The sliding surface equation after derivation is: .

[0046] in, represents the sliding surface after differentiation. Represents the attitude angle tracking error after differentiation.

[0047] Step 105: Construct an attitude stabilization controller based on the disturbance observer and the sliding surface equation.

[0048] The attitude stabilization controller is designed to achieve stable control of complex environmental disturbances and deformation processes. The attitude stabilization controller is: .

[0049] in, All represent controller parameters. .

[0050] Step 106: Based on Lyapunov stability theory, the attitude stabilization controller is used to stabilize the UAV.

[0051] The stability of the controller is proved by Lyapunov stability theory. First, the Lyapunov candidate function is selected: .

[0052] Where V represents the Lyapunov candidate function.

[0053] right Taking the first-order derivative with respect to time and substituting it into the sliding surface equation yields: .

[0054] in, represents the derived Lyapunov candidate function.

[0055] Substituting into the state space equation and the attitude stabilization controller we get: .

[0056] because , we can further deduce that: .

[0057] This proves that the designed controller is stable.

[0058] like Figure 2 This application designs a disturbance observer and combines the sliding mode control method to design an attitude stabilization controller, and uses the Lyapunov stability method to prove the stability of the controller, so that the UAV can maintain attitude stability and safe flight under the disturbance of wing tip folding deformation and complex meteorological environment disturbance, and can provide a technical reference for the flight of deformable UAVs under complex environmental conditions. Below, taking the UAV with foldable wing tip position as an example, the complex environment UAV deformation process stabilization control method provided by this embodiment is specifically described.

[0059] The wing tips of this type of UAV can be folded and deformed to adapt to different mission requirements. In addition, this type of UAV has three sets of deflection control surfaces, including elevators, ailerons and rudders. The flight control system issues a control surface deflection command to deflect the control surface, so that the UAV can maintain the desired flight attitude when disturbed. The working condition is set to a flight altitude of 1500m so that the UAV maintains a pitch angle of 0° when the wing tips are folded and deformed under environmental disturbances. The attitude variables include a longitudinal attitude component (indicated by the subscript lon) and a lateral attitude component (indicated by the subscript lat). The methods for determining the longitudinal attitude component and the lateral attitude component are both the methods shown in this embodiment. Below, taking the longitudinal attitude control as an example, the stable control method for the deformation process of the complex environment UAV provided in this embodiment is specifically described.

[0060] The first step is to collect the structural parameters of the UAV system through numerical simulation calculations, combined with wind tunnel tests and flight tests and ; Collect pitch angles through drone-mounted sensors and pitch angular velocity ; Through the flight control system, the elevator surface deflection command can be obtained through calculation Based on the data, the state space equation of the UAV longitudinal flight dynamics is established as follows: .

[0061] in, Indicates the pitch angle of the drone The derivative of ; Represents the derivative of the pitch angular velocity of the drone; Indicates the pitch angle of the drone. Indicates the pitch angular velocity of the drone, represents the elevator deflection angle, and All represent the structural parameters of the UAV longitudinal channel system. It represents the longitudinal total disturbance caused by the complex environment and wingtip folding deformation.

[0062] In the second step, based on the state space equation expression in step 1, the longitudinal state disturbance observer is designed as: .

[0063] in, Represents the longitudinal lumped disturbance caused by the complex environment and wing tip folding deformation The derivative of and Represents the pitch angular velocity of the drone The estimated value of and the longitudinal lumped disturbance caused by the complex environment and wing tip folding deformation The estimated value of They all represent disturbance observer parameters and satisfy , . is the observer structural equation, which is expressed as: .

[0064] in, All represent custom parameters and satisfy , , the designed observer disturbance error estimate satisfies , is a minimum positive value.

[0065] The third step is to design the longitudinal channel sliding surface based on the sliding mode method to achieve the overall stability control of the UAV. Assuming the desired attitude angle is , the longitudinal component of the attitude angle tracking error is , the design sliding surface of the longitudinal channel is: .

[0066] in, All represent the sliding surface parameters of the longitudinal channel and satisfy , ; Represents the longitudinal sliding surface.

[0067] Taking the first-order derivative of the longitudinal channel sliding surface with respect to time can further yield: .

[0068] in, represents the derivative of the longitudinal sliding surface.

[0069] The fourth step is to design a longitudinal attitude stabilization controller based on the designed longitudinal state observer and the longitudinal channel sliding surface. The controller solves the required rudder deflection command according to the current attitude tracking error, thereby achieving stable control of complex environmental disturbances and deformation processes. The longitudinal attitude stabilization controller is: .

[0070] in, All represent controller parameters and satisfy , represents the longitudinal attitude stabilization controller.

[0071] Step 5: Stabilize the UAV based on the longitudinal attitude stabilization controller in step 4; Specifically, when the UAV is disturbed by complex environment and wing tip folding deformation, its attitude angle will change, resulting in attitude angle tracking error. After the UAV attitude angle sensor obtains the error value, it is input into the flight control system. The flight control system calculates the elevator rudder deflection command based on the deployed longitudinal attitude stabilization controller control algorithm, thereby controlling the deflection of the UAV rudder surface and restoring the UAV attitude to the desired state.

[0072] The sixth step is to use Lyapunov stability theory to prove the stability of the longitudinal attitude stabilization controller. According to Lyapunov stability theory, assuming that there is a Lyapunov candidate function related to the system, the function is positive definite, and the derivative is negative definite, then it can be proved that the system is asymptotically stable. Therefore, the longitudinal Lyapunov candidate function is first selected as: .

[0073] in, is the longitudinal Lyapunov candidate function.

[0074] right Taking the first-order derivative with respect to time and substituting it into the expression of the sliding surface, we can obtain: .

[0075] in, is the longitudinal Lyapunov candidate function after differentiation.

[0076] Substituting the state space equation and the longitudinal attitude stability controller expression into the above formula can further derive: .

[0077] because The above formula can be further deduced as follows: .

[0078] It can be found that the derivative of the Lyapunov candidate function is negative definite, so it can be proved that the designed longitudinal attitude controller is stable. Finally, the designed longitudinal attitude controller can realize the stable flight control of the wingtip folding deformation process of the UAV under complex environmental conditions.

[0079] In an exemplary embodiment, a computer device is provided, which may be a server or a terminal. The computer device includes a processor, a memory, an input / output interface (I / O for short) and a communication interface. The processor, the memory and the input / output interface are connected via a system bus, and the communication interface is connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a method for stabilizing the deformation process of a complex environment unmanned aerial vehicle is implemented.

[0080] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0081] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0082] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0083] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0084] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0085] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for stable control of deformation process of unmanned aerial vehicle in complex environment, characterized in that: include: Construct state-space equations; The state space equation is used to describe the flight dynamics parameters of the UAV during deformation in a complex environment; Based on the state space equation, a disturbance observer is constructed; the disturbance observer is used to observe the lumped disturbance caused by the complex environment and the wing tip folding deformation; According to the expected attitude angle, determining the attitude angle tracking error; According to the attitude angle tracking error, the sliding surface equation is constructed; Constructing an attitude stabilization controller according to the disturbance observer and the sliding surface equation; Based on Lyapunov stability theory, the attitude stabilization controller is used to stabilize the UAV.

2. The method for stable control of deformation process of a UAV in a complex environment according to claim 1 is characterized in that: After constructing the sliding surface equation based on the attitude angle tracking error, it also includes: The sliding surface equation is differentiated to obtain a differentiated sliding surface equation.

3. The method for stable control of deformation process of a UAV in a complex environment according to claim 2 is characterized in that: The state space equation is: ； in, Represents the drone attitude angle variable The derivative of ; Represents attitude angular velocity variable The derivative of ; and All represent the structural quantity of the UAV system; Indicates the control quantity of the UAV system; Represents the total disturbance caused by the complex environment and the wingtip folding deformation.

4. The method for stable control of deformation process of a UAV in a complex environment according to claim 3 is characterized in that: The disturbance observer is: ； ； in, Represents the estimator of the drone's attitude angle variable The derivative of ; An estimate of the total disturbance caused by the complex environment and the wing tip folding deformation The derivative of ; are disturbance observer parameters, , ; and All represent the observer structural equation; Both represent custom parameters. , ; Represents a symbolic function.

5. The method for stable control of deformation process of a UAV in a complex environment according to claim 4 is characterized in that: The constraints of the disturbance observer are: ; in, is a minimum positive value.

6. The method for stable control of deformation process of a UAV in a complex environment according to claim 5 is characterized in that: The sliding surface equation is: ； in, represents the sliding surface; All represent sliding surface parameters; represents the attitude angle tracking error, , represents the desired attitude angle.

7. The method for stable control of deformation process of a UAV in a complex environment according to claim 6 is characterized in that: The sliding surface equation after derivation is: ； in, represents the sliding surface after differentiation; Represents the attitude angle tracking error after differentiation.

8. The method for stable control of deformation process of a UAV in a complex environment according to claim 7 is characterized in that: The attitude stabilization controller is: ； in, All represent controller parameters. .

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