A UAV control method, device and medium based on random key stream

Abstract

The present application discloses a method, device, and medium for controlling a drone based on a random key stream, and relates to the field of aircraft control technology. The method includes: presetting a chaotic initial value for the main chaotic system of the encryption end; selecting a switching strategy based on the current state component of the main chaotic system to switch the auxiliary chaotic system; generating a random key stream coefficient through a seed random number generator, combining the random key stream coefficient with the chaotic initial value to obtain a private key; obtaining the plaintext of the aircraft measurement data, injecting the plaintext into the chaotic system, and generating ciphertext in combination with the random key stream coefficient; transmitting the ciphertext to the decryption end, synchronizing the private key and the switching strategy at the decryption end, and restoring the plaintext; inputting the restored plaintext into a state feedback controller to generate an anti-saturation control instruction, and the state feedback controller includes a nonlinear compensation function. The present application uses the above method to implement encryption and decryption of the aircraft's measurement data using the chaotic system key stream, extend the private key length, and improve security.

Description

Technical Field

[0001] The present application relates to the field of aircraft control technology, and in particular to a method, device, and medium for controlling a drone based on a random key stream. Background Art

[0002] As a new type of aircraft that combines the high-speed cruising capabilities of fixed-wing aircraft with the flexible take-off and landing characteristics of rotary-wing aircraft, the complexity and industry challenges of Vertical Take-Off and Landing Fixed-Wing Aircraft (VTOL-FW) are mainly reflected in the contradictions between safety, real-time performance and adaptability to dynamic environments.

[0003] Currently, technological development in this field faces dual pressures: on the one hand, the rapid penetration of military and civilian scenarios requires aircraft to maintain reliable control in complex electromagnetic environments and highly dynamic airspace; on the other hand, existing security architectures struggle to meet the real-time encryption requirements of aircraft during mode switching, significantly expanding the attack surface. Successful malicious attacks are concentrated during takeoff and landing, and are carried out by reverse engineering unencrypted measurement data, highlighting the fatal flaw of traditional communication protocols that rely solely on basic verification mechanisms.

[0004] Furthermore, existing encryption technologies are limited. While general-purpose algorithms like AES-256 (Advanced Encryption Standard - 256-bit Key) offer excellent data confidentiality, their millisecond-level computational latency cannot meet the stringent real-time measurement feedback requirements during transitional flight. This is particularly true during critical maneuvers such as tilt-rotor rotation or thrust vectoring adjustments, where encryption delays can lead to attitude instability or even crashes. Furthermore, the frequency hopping and topology reconfiguration caused by multimodal flight frequently render traditional static key distribution mechanisms ineffective. While most commercial flight control systems utilize full-link encryption, their lack of differentiated protection places them at high risk of system crashes in the face of selective replay attacks. This "security redundancy trap" stems from existing solutions failing to incorporate dynamic flight state parameters into the encryption matrix, resulting in a disconnect between key updates and flight phases.

[0005] The V-247 drone uses a hardware acceleration module to compress AES-256 processing time to 60ms, but this still fails to meet transitional requirements. Airbus' quantum key distribution technology, while theoretically resistant to cracking, is limited by the cost of deploying quantum repeaters and is only suitable for fixed-route scenarios. Domestically, a lightweight national encryption algorithm developed by the Institute of Automation under the Chinese Academy of Sciences reduces encryption latency to 35ms, but the lack of a dynamic key update mechanism leads to a surge in bit error rates in frequency-hopping scenarios. DJI's command signature verification technology, while resistant to replay attacks, suffers from control loop lag due to the time-consuming signature generation process. These examples demonstrate that simply optimizing algorithms or hardware alone cannot systematically address the balance between security and real-time performance.

[0006] Furthermore, technological breakthroughs are evolving from single-layer encryption to cross-domain collaboration. The widespread adoption of distributed electric propulsion technology, such as NASA's GL-10 Lightning UAV, has spurred the need for an integrated "energy-communication-control" security architecture, driving deeper integration of encryption mechanisms with the powertrain. For example, the Boeing Phantom Swift leverages the tilting characteristics of its wingtip ducted propulsion units to generate a dynamic key seed, binding the aircraft's motion state to encryption timing and initially achieving 15ms-level encryption efficiency. Furthermore, adaptive key distribution technology, leveraging link quality prediction models, improves key synchronization success rates in frequency-hopping scenarios, significantly exceeding the baseline of traditional solutions. In the future, the integration of chaotic encryption and artificial intelligence may become crucial. By using neural networks to analyze low-altitude airflow data in real time and optimize encryption matrix parameters, command integrity verification and operation legitimacy assessment can be simultaneously completed within milliseconds, thereby establishing a three-pronged security protection system characterized by "spatiotemporal correlation, dynamic evolution, and autonomous repair."

[0007] Furthermore, during the complex and highly dynamic mode transitions of VTOL-FW, from hover to level flight and back again, the real-time, integrity, and authenticity of measurement information are crucial for maintaining stability in the Flight Control System (FCS). During these transitions, the aircraft experiences dramatic changes in aerodynamic characteristics and uneven control efficiency, such as changes in tiltrotor angle and thrust vector direction adjustments. The FCS's reliance on core measurement data, such as attitude angle, angular rate, acceleration, position, and velocity, reaches peak levels. If an attacker tampers with, replays, or forges these millisecond-updated measurements, for example by injecting false attitude angle data, the FCS will generate catastrophic control commands based on erroneous state perception. Actuators are forced to respond to these erroneous commands, instantly driving them to their physical limits—a phenomenon known as actuator saturation. Saturated actuators not only lose the ability to further adjust flight attitude, but also generate unexpected, high-amplitude erroneous actuation torques that can directly lead to loss of control, instability, and even structural damage. Therefore, ensuring the security of measurement information throughout the entire transmission and processing chain is the first and most important technical barrier to prevent malicious attacks from inducing actuator saturation and causing catastrophic consequences.

[0008] Through the above analysis, the problems and defects of the existing technology are as follows:

[0009] The aircraft encryption algorithm in the existing technology cannot meet the real-time encryption requirements of measurement data during the transition flight phase due to delays, and the encryption delay of the measurement data causes the actuator to saturate and lose control, further causing disasters. Summary of the Invention

[0010] The embodiments of the present application provide a drone control method, device, and medium based on a random key stream, which can solve the problem that the aircraft encryption algorithm in the prior art cannot meet the real-time encryption requirements of measurement data during the transition flight phase due to delay, and the encryption delay of the measurement data causes the actuator to saturate and lose control, further causing a disaster.

[0011] In the first aspect, an embodiment of the present application provides a drone control method based on a random key stream, the method comprising: presetting a chaotic initial value for the main chaotic system of the encryption end based on a chaotic system including a main chaotic system and an auxiliary chaotic system; selecting a switching strategy according to the current state component of the main chaotic system to switch the auxiliary chaotic system; generating a random key stream coefficient through a seed random number generator, combining the random key stream coefficient with the chaotic initial value to obtain a private key; obtaining plaintext of aircraft measurement data, injecting the plaintext into the chaotic system, and generating ciphertext in combination with the random key stream coefficient; transmitting the ciphertext to the decryption end, synchronizing the private key and the switching strategy at the decryption end, and restoring the plaintext; inputting the restored plaintext into a state feedback controller to generate an anti-saturation control instruction, and the state feedback controller includes a nonlinear compensation function.

[0012] In one implementation of the present application, a switching strategy is selected based on the current state components of the main chaotic system to switch the auxiliary chaotic system, specifically including: based on the auxiliary chaotic system including a first auxiliary system and a second auxiliary system; calculating the state components of the main chaotic system in real time according to the initial value, and activating the first auxiliary system when the state component is less than a preset value; activating the second auxiliary system when the state component is greater than a preset value.

[0013] In one implementation of the present application, a random key stream coefficient is generated by a seed random number generator, and the random key stream coefficient is combined with a chaotic initial value to obtain a private key, specifically including: using a digital sequence of a preset length as a seed, inputting the seed into a random number generator to generate a random key stream coefficient; using the seed as a prefix of the private key, and combining it with the chaotic initial value to obtain the private key.

[0014] In one implementation of the present application, the ciphertext is transmitted to the decryption end, the private key and switching strategy are synchronized at the decryption end, and the plaintext is restored, specifically including: distributing the seed to the decryption end through a secure channel; synchronously running the same random number generation algorithm at the encryption end and the decryption end; synchronously running the main chaotic system according to the chaotic initial value in the private key, and determining the auxiliary chaotic system.

[0015] In one implementation of the present application, the restored plaintext is input into a state feedback controller to generate anti-saturation control instructions, specifically including: establishing a linear state space model of a vertical take-off and landing fixed-wing aircraft at a preset working point, the linear state space model including an output saturation constraint; using a hyperbolic tangent function to approximate the saturation constraint; collecting the aircraft state vector, the state vector including position, velocity, attitude angle and angular velocity components; designing a state feedback control law so that the output value of the state feedback controller is the inverse hyperbolic tangent function of the product of the state vector and a preset gain matrix, and the gain matrix is ​​used to make all eigenvalues ​​of the state vector have a negative real part.

[0016] In one implementation of the present application, a state feedback control law is designed, and the output value is the inverse hyperbolic tangent function of the state vector and the preset gain matrix, specifically including: calculating the product of the state vector and the feedback gain parameter to generate an intermediate control vector; applying the inverse hyperbolic tangent function to each component of the intermediate control vector to obtain the operation result; and outputting the operation result to the actuator to drive the rudder and the motor.

[0017] In one implementation of the present application, after using the hyperbolic tangent function to approximate the saturation constraint, the method also includes: calculating the approximation error between the output value of the hyperbolic tangent function and the saturation constraint, and estimating the upper bound of the approximation error; injecting the upper bound into the state feedback control law to obtain the compensation gain, and adaptively adjusting the compensation gain.

[0018] In one implementation of the present application, the method further includes: freezing the current control instruction when the number of consecutive decryption failures exceeds a threshold number; switching to a preset gain matrix, and calculating a conservative control instruction according to the preset gain matrix.

[0019] In a second aspect, an embodiment of the present application also provides a drone control device based on a random key stream, the device comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so as to enable the at least one processor to: preset a chaotic initial value for the main chaotic system of the encryption end based on the chaotic system comprising a main chaotic system and an auxiliary chaotic system; select a switching strategy according to the current state component of the main chaotic system to switch the auxiliary chaotic system; generate a random key stream coefficient through a seed random number generator, combine the random key stream coefficient with the chaotic initial value to obtain a private key; obtain plaintext of aircraft measurement data, inject the plaintext into the chaotic system, and generate ciphertext in combination with the random key stream coefficient; transmit the ciphertext to the decryption end, synchronize the private key and the switching strategy at the decryption end, and restore the plaintext; input the restored plaintext into the state feedback controller to generate an anti-saturation control instruction, and the state feedback controller includes a nonlinear compensation function.

[0020] On the third aspect, an embodiment of the present application also provides a non-volatile computer storage medium for drone control based on a random key stream, which stores computer executable instructions, and the computer executable instructions are set to: based on the chaotic system including a main chaotic system and an auxiliary chaotic system, presetting the chaotic initial value for the main chaotic system of the encryption end; selecting a switching strategy according to the current state component of the main chaotic system to switch the auxiliary chaotic system; generating a random key stream coefficient through a seed random number generator, combining the random key stream coefficient with the chaotic initial value to obtain a private key; obtaining the plaintext of the aircraft measurement data, injecting the plaintext into the chaotic system, and generating ciphertext in combination with the random key stream coefficient; transmitting the ciphertext to the decryption end, synchronizing the private key and the switching strategy at the decryption end, and restoring the plaintext; inputting the restored plaintext into the state feedback controller to generate an anti-saturation control instruction, and the state feedback controller includes a nonlinear compensation function.

[0021] The embodiments of the present application provide a drone control method, device, and medium based on a random key stream. By switching a chaotic system in an encryption algorithm and randomly distributing key stream coefficients, the chaotic system key stream is amplified or reduced. The new key stream is then used to encrypt and decrypt the aircraft's measurement data, thereby improving security by extending the private key length. In addition, the key stream coefficients generated by a seed random number generator also improve the security of encryption and decryption. On the basis of ensuring the security of the measurement data, the hyperbolic tangent function and state feedback control law are used to convert the actuator's physical constraints into smooth functions, eliminating the flutter phenomenon caused by traditional hard saturation, designing an aircraft control algorithm that is resistant to actuator saturation, and improving the application of aircraft in practical scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0023] Figure 1 A flowchart of a drone control method based on random key stream provided in an embodiment of the present application;

[0024] Figure 2 A schematic diagram of the overall process architecture of a drone control method based on random key stream provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the encryption end process of a drone control method based on random key stream provided in an embodiment of the present application;

[0026] Figure 4 A schematic diagram of the decryption end process of a drone control method based on a random key stream provided in an embodiment of the present application;

[0027] Figure 5 A schematic diagram of random key stream expansion and distribution for a random key stream-based drone control method provided in an embodiment of the present application;

[0028] Figure 6 A schematic diagram of the internal structure of a drone control device based on a random key stream provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0030] The embodiments of the present application provide a drone control method, device, and medium based on a random key stream, which solves the problem that the aircraft encryption algorithm in the prior art cannot meet the real-time encryption requirements of measurement data during the transition flight phase due to delay, and the encryption delay of the measurement data causes the actuator to saturate and lose control, further causing a disaster.

[0031] The technical solutions proposed in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0032] Figure 1 This is a flow chart of a drone control method based on random key stream provided by an embodiment of the present application. Figure 1 As shown, the embodiment of the present application provides a drone control method based on a random key stream, which specifically includes the following steps:

[0033] Step 10: Based on the fact that the chaotic system includes a main chaotic system and an auxiliary chaotic system, a chaotic initial value is preset for the main chaotic system of the encryption end.

[0034] The embodiment of the present application consists of a chaotic encryption part based on key stream coefficients and an aircraft control part, specifically a saturation control algorithm for vertical take-off and landing fixed-wing aircraft based on lengthened key and switching chaotic system encryption. The specific algorithm architecture diagram is as follows Figure 2 The following two parts will be introduced separately.

[0035] First, it can be understood that the Lorenz nonlinear system is a typical chaotic system. Its dynamical equations consist of three nonlinear differential equations, with parameters including σ (Prandtl number), ρ (Rayleigh number), and β. This system is famous for the "butterfly effect," exhibiting the typical chaotic characteristic of exponential trajectory divergence caused by small differences in initial conditions. Its attractor is a double-scroll structure, and its state equation is:

[0036]

[0037] in, , , is the state of the system, is the output of the system. , , When , the Lorenz system shows chaotic phenomenon. It is worth noting that the state of the Lorenz chaotic system is The amplitude is .

[0038] The Chen chaotic system is considered an extension of the Lorenz system. Its equation form is similar to that of the Lorenz system, but by adjusting parameters and coupling terms, the Chen system exhibits more complex dynamical behavior. For example, the attractor structure exhibits both folding and rotational characteristics, and there is a richer range of chaotic and periodic state switching within the parameter range. Due to its high parameter sensitivity, this system is widely used in secure communications and chaotic synchronization control research. The state space expression of the Chen nonlinear system is given as follows:

[0039]

[0040] in, , , is the state of the system, is the output of the system. , , When , the Chen system shows chaotic phenomenon.

[0041] In this step, for the Lorenz chaotic system and the Chen chaotic system, the embodiment of the present application first considers injecting the plaintext to be encrypted into the output equations of the two systems respectively, and then multiplying the key stream by a coefficient respectively. and ,Right now:

[0042] Lorenz plaintext injection system :

[0043]

[0044] Chen plaintext injection system :

[0045]

[0046] Then inject two plaintexts into the system and The generalized switching chaotic system is formed, namely:

[0047]

[0048] in, Is the switching signal, indicating that at time , chaotic system or is activated.

[0049] Switching signal The switching strategy is as follows:

[0050] In the encryption module, the embodiment of the present application considers the Lorenz chaotic system as the basis for the judgment model, and sets the initial value of the chaotic system. Under these conditions, the encryption end determines the state of the Lorenz chaotic system. ,if ,but ;if ,but The mathematical expression is as follows:

[0051]

[0052] Chaotic encryption algorithms based on switching chaotic systems such as Figure 3 As shown. Note that this encryption scheme can be extended to multiple chaotic systems for switching. Specifically, consider the Lorenz chaotic system, the Chen chaotic system and the Rossler chaotic system. The Rossler system is a chaotic model with a relatively simple structure, containing only one nonlinear term. Under parameter adjustment, it can present the mixed characteristics of spiral attractor and folding trajectory. Typical behaviors include single vortex chaos and periodic oscillation. Due to its low-dimensional characteristics, the Rossler system is often used to analyze the basic mechanism of chaos, and is used as a benchmark model for theoretical research in interdisciplinary fields such as chemical oscillations and biological rhythms. The state equation of the Rossler chaotic system is as follows:

[0053]

[0054] in, , , is the state of the system, is the output of the system. , , , When , the Rossler system exhibits chaotic phenomena.

[0055] Step 20: Select a switching strategy based on the current state components of the main chaotic system to switch the auxiliary chaotic system.

[0056] As an optional embodiment, a switching strategy is selected based on the current state components of the main chaotic system to switch the auxiliary chaotic system, which may specifically include: based on the auxiliary chaotic system including a first auxiliary system and a second auxiliary system; step 201: calculating the state components of the main chaotic system in real time according to the initial value, and activating the first auxiliary system when the state components are less than the preset value; step 202: activating the second auxiliary system when the state components are greater than the preset value.

[0057] In this step, the Lorenz chaotic system is still used as the basic model, but the switching signal The switching strategy needs to be updated as follows:

[0058] When the state of the Lorenz chaotic system ,but ; When the state of the Lorenz chaotic system ,but ; The state of the Lorenz chaotic system ,but The mathematical expression is as follows:

[0059]

[0060] like Figure 3 As shown, note that the key stream coefficient is further introduced , and The generation of key stream coefficients can be combined with the initial value of the Lorenz system state as the private key for chaotic encryption and decryption, which will increase the length of the private key; at the same time, the key stream coefficients can be real numbers, so the encryption and decryption scheme greatly improves the security.

[0061] The key stream coefficients are explained below.

[0062] Step 30: Generate a random key stream coefficient through a seed random number generator, combine the random key stream coefficient with the chaotic initial value, and obtain the private key.

[0063] As an optional embodiment, a random key stream coefficient is generated by a seed random number generator, and the random key stream coefficient is combined with a chaotic initial value to obtain a private key. Specifically, it may include: Step 301: Using a digital sequence of a preset length as a seed, inputting the seed into a random number generator to generate a random key stream coefficient; Step 302: Using the seed as a prefix of the private key, and combining it with the chaotic initial value to obtain the private key.

[0064] In this step, in order to increase system security, the embodiment of the present application adopts an extended key scheme of random key stream coefficients, which is specifically described as follows: The 9 digits in the cipher are used as the seed and also as the first two digits of the private key; the encryption unit and the decryption unit share this seed; then a random number generator is used to generate the cipher based on the seed. , the encryption unit and decryption unit generate the same random number at the same time , these two random numbers are used as key stream coefficients to prepare for subsequent plaintext encryption and decryption.

[0065] Chaotic cryptographic systems leverage the high sensitivity and unpredictability of chaotic sequences to achieve excellent encryption performance, making them particularly suitable for communication scenarios that are sensitive to initial values ​​and require high complexity. However, system security relies heavily on the confidentiality and synchronization of keys, initial conditions, and system parameters. Therefore, key distribution is an essential component of the security architecture of chaotic cryptographic systems. If the key distribution process is insecure, even if the encryption algorithm itself is highly chaotic, key leakage can easily lead to system failure. A secure and reliable key distribution mechanism not only ensures the synchronous generation of chaotic sequences by both communicating parties but also prevents man-in-the-middle and replay attacks, making it a fundamental prerequisite for the practical application of chaotic cryptographic systems.

[0066] The chaotic sequence generated by a chaotic system is extremely sensitive to the system's initial value. A slight perturbation of the initial value can drastically change the chaotic sequence generated by the chaotic system. Therefore, the initial value of the chaotic system is usually used as the key for chaotic encryption. Since this scheme uses a switching chaotic system as the key stream generator, the key is selected as:

[0067]

[0068] Therefore, the private key structure is ,like Figure 5 shown.

[0069] Step 40: Obtain the plaintext of the aircraft measurement data, inject the plaintext into the chaotic system, and generate ciphertext by combining it with the random key stream coefficient.

[0070] Step 50: Transmit the ciphertext to the decryption end, synchronize the private key and switching strategy at the decryption end, and restore the plaintext.

[0071] In this step, the presence of a decryption module is crucial in chaotic encryption communication systems. Because the encryption process introduces a chaotic sequence that performs complex nonlinear transformations on the original information, the receiving end must have an effective decryption mechanism to accurately reconstruct the original data based on the known key information. The high sensitivity of chaotic systems means that even small parameter errors can cause decryption failures. Therefore, the decryption module must not only achieve synchronous reproduction of the chaotic sequence but also ensure a certain degree of robustness against disturbances and noise. Without a decryption module, the encrypted information cannot be correctly recovered, rendering the entire communication process meaningless. Therefore, designing a high-precision, highly synchronized, and robust decryption module is fundamental to the reliable application of chaotic encryption systems.

[0072] As an optional embodiment, the ciphertext is transmitted to the decryption end, the private key and switching strategy are synchronized at the decryption end, and the plaintext is restored. Specifically, it may include: step 501: distributing the seed to the decryption end through a secure channel; step 502: synchronously running the same random number generation algorithm at the encryption end and the decryption end; step 503: synchronously running the main chaotic system according to the chaotic initial value in the private key, and determining the auxiliary chaotic system.

[0073] In this step, as mentioned in step 302, the encryption unit and the decryption unit share the seed; then a random number generator is used to generate the random number according to the seed. , the encryption unit and decryption unit generate the same random number at the same time The decryption end reproduces the same chaotic sequence based on the chaotic initial value.

[0074] Then, the key stream is subtracted from the ciphertext to obtain the measurement plaintext, such as Figure 4 As shown, the decryption equation is as follows:

[0075]

[0076] Step 60: Input the restored plain text into a state feedback controller to generate an anti-saturation control instruction. The state feedback controller includes a nonlinear compensation function.

[0077] First of all, it can be understood that a vertical take-off and landing fixed-wing aircraft is an innovative aircraft that combines the vertical take-off and landing capabilities of a multi-rotor with the long-endurance and high-speed flight characteristics of a fixed-wing. Its core design achieves vertical take-off and landing through a multi-rotor or tilt-rotor power system, and then switches to fixed-wing mode for efficient cruising.

[0078] Typically, a vertical take-off and landing fixed-wing aircraft is characterized by 12 states to characterize its dynamic and kinematic models, namely , representing position, velocity, attitude, and angular velocity, respectively. Due to the coupling between the states of a vertical take-off and landing fixed-wing aircraft, the dynamic system of a vertical take-off and landing fixed-wing aircraft has strong nonlinear characteristics. These systems are affected by factors such as aerodynamic changes, large attitude adjustments, and coupling with the propulsion system. Designing a controller directly for a complete nonlinear model often faces complex modeling, difficult analysis, and difficulty in solving control laws.

[0079] Therefore, in this step, in order to simplify the controller design, we can choose to linearize the system near the specific operating point related to the flight mission. Through the linearization of the operating point, we can obtain a local linear approximate model, which enables the application of traditional linear control theory: pole placement, optimal control, robust control, etc., thereby greatly reducing the complexity of controller design and stability analysis, while facilitating efficient engineering deployment and performance verification. Therefore, after the linearization of the operating point, the linear system description is as follows:

[0080]

[0081] in , ,

[0082]

[0083]

[0084] x(t) is the system's state vector, containing position, velocity, attitude angle, angular velocity, and other variables, describing the current state of the aircraft. A is the system matrix, reflecting the aircraft's inherent dynamic characteristics, such as inertia and aerodynamic coupling, which determine how the state naturally changes over time. B is the input matrix, describing the influence of control inputs on the state, such as how rudder deflection changes the aircraft's attitude. u(t) is the control input vector, such as motor thrust and rudder deflection angle, generated by the controller. This equation describes how the aircraft's state changes over time—the current state x and the control input u together determine the state at the next moment.

[0085] The output equation of the system is ;

[0086]

[0087] The encryption function defined in the embodiment of the present application can be ,Right now , the decryption function is ,Right now

[0088] As an optional embodiment, the restored plain text is input into a state feedback controller to generate anti-saturation control instructions, which may specifically include: Step 601: establishing a linear state space model of the vertical take-off and landing fixed-wing aircraft at a preset working point, the linear state space model including an output saturation constraint.

[0089] In this step, it is assumed that the decryption error is 0, and considering that the actuator of the vertical take-off and landing fixed-wing aircraft needs to be limited, it is necessary to study the actuator saturation problem. In this problem, the linearization equation of the vertical take-off and landing fixed-wing aircraft is changed to:

[0090]

[0091] The saturation function is expressed as follows:

[0092]

[0093] in, It is the upper bound of the saturated input. The embodiment of the present application uses the hyperbolic tangent function to limit the amplitude of the state control input, that is, it does include the constraints of the upper and lower limits of the physical output capacity of the actuator.

[0094] Step 602: using a hyperbolic tangent function to approximate the saturation constraint;

[0095] In this step, the mathematical properties of the hyperbolic tangent function are used to construct a smooth and continuous function to simulate and approximate the physical output limit of the actuator. A smooth function is defined as:

[0096]

[0097] Then, the saturation function can be expressed as:

[0098]

[0099] Approximation error Is a bounded unknown function, assuming the upper bound is ,but , the linearized equation of the vertical take-off and landing fixed-wing aircraft is transformed into:

[0100]

[0101] Step 603: Collect the aircraft state vector, which includes position, velocity, attitude angle and angular velocity components; Step 604: Design a state feedback control law so that the output value of the state feedback controller is the inverse hyperbolic tangent function of the product of the state vector and a preset gain matrix. The gain matrix is ​​used to make all eigenvalues ​​of the state vector have negative real parts.

[0102] In this step, the final output control command value is equal to the result vector obtained by multiplying the current state vector of the aircraft by the preset gain matrix. Then, the mathematical operation of the inverse hyperbolic tangent function is performed on each element of the result vector. After that, the specific parameter values ​​of the gain matrix are adjusted and determined, so that the control system formed after applying this control law has stable internal dynamic characteristics.

[0103] As an optional embodiment, a state feedback control law is designed, and the output value is the inverse hyperbolic tangent function of the state vector and the preset gain matrix. Specifically, it may include: Step 6041: Calculate the product of the state vector and the feedback gain parameter to generate an intermediate control vector; Step 6042: Apply the inverse hyperbolic tangent function to each component of the intermediate control vector to obtain the operation result; Step 6043: Output the operation result to the actuator to drive the rudder and the motor.

[0104] The present embodiment assumes a simple state feedback control scheme, namely:

[0105]

[0106] in To control the gain parameters, in a control system, state feedback can directly utilize all or part of the system state variables and adjust the input in real time to achieve precise regulation of the system's dynamic performance. The control law is then solved as:

[0107]

[0108] Here the symbol arh=arctanh.

[0109] Compared to control methods that rely solely on output feedback, state feedback can significantly improve system stability, response speed, and robustness. It not only optimizes the system's dynamic characteristics through pole placement, but also enhances its resistance to disturbances and model uncertainties. It is the basis for implementing high-performance control strategies such as optimal control, adaptive control, and robust control. The state equation of the closed-loop control system of a vertical take-off and landing fixed-wing aircraft is as follows:

[0110]

[0111] In the process of adjusting the control system parameters, as long as the control gain is selected Make The real part of the eigenvalue is less than 0, which can theoretically prove that the closed-loop system is stable from the saturation function approximation error to the input state, which can satisfy the boundedness of the state of the system near the operating point.

[0112] As an optional embodiment, after using the hyperbolic tangent function to approximate the saturation constraint, the method may also include: calculating the approximation error between the output value of the hyperbolic tangent function and the saturation constraint, and estimating the upper bound of the approximation error; injecting the upper bound into the state feedback control law to obtain a compensation gain, and adaptively adjusting the compensation gain.

[0113] In this step, the limitations of traditional static saturation compensation can be overcome by actively suppressing the impact of the hyperbolic tangent function approximation error on stability through an error observer and an adaptive injection mechanism, thereby reducing the deviation between the actual output of the actuator and the theoretical instruction.

[0114] As an optional embodiment, the method may further include: freezing the current control instruction when the number of consecutive decryption failures exceeds a threshold number; switching to a preset gain matrix, and calculating a conservative control instruction according to the preset gain matrix.

[0115] In this step, a cross-domain action between encryption failure and control security is established, and the control instructions are forced to be restricted to the linear working area of ​​the actuator through the security gain matrix to avoid instantaneous saturation and loss of control caused by malicious attacks or channel failures.

[0116] In summary, the present invention utilizes the characteristic that chaotic nonlinear systems are extremely sensitive to initial values, and designs a saturation control algorithm for vertical take-off and landing fixed-wing aircraft based on encryption of chaotic systems with key stream coefficient switching. This encryption algorithm relies on different chaotic systems and, according to the designed switching strategy, utilizes key streams generated by different chaotic systems and randomly generated key stream coefficients to encrypt the aircraft measurement data, so that the measurement data is transmitted in the form of ciphertext; when the decryption module receives the ciphertext measurement data, it uses the key to obtain the switching strategy of the key stream, and then calculates the original measurement data. In the key distribution module, a seed random number generator is used to distribute key stream coefficients, increase the length of the private key, distribute the key, and improve the security of plaintext encryption. The embodiment of the present application is applied to the encryption of measurement data of vertical take-off and landing aircraft, so that sensitive measurement data of the aircraft is protected.

[0117] In addition, this scheme designs an anti-actuator saturation state feedback control algorithm based on the characteristics of the hyperbolic tangent function. This control algorithm, combined with the proposed chaotic encryption and decryption algorithm, makes the aircraft flight safer and can be further applied in practical scenarios.

[0118] The above is an embodiment of the method proposed in this application. Based on the same inventive concept, this application embodiment also provides a drone control device based on a random key stream, the structure of which is as follows: Figure 6 shown.

[0119] Figure 6 This is a schematic diagram of the internal structure of a drone control device based on a random key stream provided in an embodiment of the present application. Figure 6 As shown, the equipment includes:

[0120] at least one processor 601;

[0121] and, a memory 602 communicatively coupled to the at least one processor;

[0122] Among them, the memory 602 stores instructions that can be executed by at least one processor, and the instructions are executed by at least one processor 601 so that the at least one processor 601 can: based on the chaotic system including the main chaotic system and the auxiliary chaotic system, preset the chaotic initial value for the main chaotic system of the encryption end; select the switching strategy according to the current state component of the main chaotic system to switch the auxiliary chaotic system; generate a random key stream coefficient through a seed random number generator, combine the random key stream coefficient with the chaotic initial value to obtain a private key; obtain the plaintext of the aircraft measurement data, inject the plaintext into the chaotic system, and generate ciphertext in combination with the random key stream coefficient; transmit the ciphertext to the decryption end, synchronize the private key and the switching strategy at the decryption end, and restore the plaintext; input the restored plaintext into the state feedback controller to generate an anti-saturation control instruction, and the state feedback controller includes a nonlinear compensation function.

[0123] Some embodiments of the present application provide corresponding Figure 1 A non-volatile computer storage medium for UAV control based on a random key stream stores computer executable instructions, wherein the computer executable instructions are configured to: based on a chaotic system including a main chaotic system and an auxiliary chaotic system, preset a chaotic initial value for the main chaotic system of an encryption end; select a switching strategy according to the current state component of the main chaotic system to switch the auxiliary chaotic system; generate a random key stream coefficient through a seed random number generator, combine the random key stream coefficient with the chaotic initial value to obtain a private key; obtain plaintext of aircraft measurement data, inject the plaintext into the chaotic system, and generate ciphertext by combining the random key stream coefficient; transmit the ciphertext to a decryption end, synchronize the private key and the switching strategy at the decryption end, and restore the plaintext; input the restored plaintext into a state feedback controller to generate an anti-saturation control instruction, wherein the state feedback controller includes a nonlinear compensation function.

[0124] The various embodiments in this application are described in a progressive manner. Similar portions between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from the other embodiments. In particular, the IoT device and media embodiments are generally similar to the method embodiments, so their description is relatively simple. For relevant portions, refer to the description of the method embodiments.

[0125] The system and medium provided in the embodiments of the present application correspond one-to-one to the method. Therefore, the system and medium also have similar beneficial technical effects to their corresponding methods. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the system and medium will not be repeated here.

[0126] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0127] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0128] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0129] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0130] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0131] Memory may include non-permanent storage in a computer-readable medium, in the form of random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

[0132] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can be implemented using any method or technology to store information. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change RAM (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media such as modulated data signals and carrier waves.

[0133] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0134] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A UAV control method based on random key stream, characterized in that: The method comprises: Based on the fact that the chaotic system includes a main chaotic system and an auxiliary chaotic system, a chaotic initial value is preset for the main chaotic system of the encryption end; Selecting a switching strategy according to the current state component of the main chaotic system to switch the auxiliary chaotic system specifically includes: Based on the auxiliary chaotic system including a first auxiliary system and a second auxiliary system; Calculating the state component of the main chaotic system in real time according to the initial value, and activating the first auxiliary system when the state component is less than a preset value; activating the second auxiliary system when the state component is greater than a preset value; Generate a random key stream coefficient by using a seed random number generator, and combine the random key stream coefficient with the chaotic initial value to obtain a private key, specifically including: Using a digital sequence of a preset length as a seed, inputting the seed into a random number generator to generate the random key stream coefficients; Using the seed as a prefix of the private key and combining it with the chaotic initial value to obtain the private key; Obtaining plaintext of aircraft measurement data, injecting the plaintext into the chaotic system, and generating ciphertext by combining the random key stream coefficients; Transmitting the ciphertext to a decryption terminal, synchronizing the private key and the switching strategy at the decryption terminal, and restoring the plaintext; The restored plaintext is input into a state feedback controller to generate an anti-saturation control instruction, wherein the state feedback controller includes a nonlinear compensation function.

2. The method for controlling a drone based on a random key stream according to claim 1, characterized in that: Transmitting the ciphertext to the decryption end, synchronizing the private key and the switching strategy at the decryption end, and restoring the plaintext, specifically includes: Distributing the seed to the decryption terminal through a secure channel; Synchronously running the same random number generation algorithm on the encryption end and the decryption end; According to the chaotic initial value in the private key, the main chaotic system is synchronously operated and the auxiliary chaotic system is determined.

3. The method for controlling a drone based on a random key stream according to claim 1, wherein: The restored plaintext is input into the state feedback controller to generate anti-saturation control instructions, specifically including: Establishing a linear state-space model of a vertical take-off and landing fixed-wing aircraft at a preset operating point, wherein the linear state-space model includes an output saturation constraint; Using a hyperbolic tangent function to approximate the saturation constraint; Collecting an aircraft state vector, wherein the state vector includes position, velocity, attitude angle, and angular velocity components; A state feedback control law is designed so that the output value of the state feedback controller is an inverse hyperbolic tangent function of the state vector and a preset gain matrix, and the gain matrix is ​​used to make all eigenvalues ​​of the state vector have negative real parts.

4. The method for controlling a drone based on a random key stream according to claim 3, wherein: Design a state feedback control law, the output value of which is the inverse hyperbolic tangent function of the state vector and the preset gain matrix, specifically including: Calculating the product of the state vector and the feedback gain parameter to generate an intermediate control vector; Applying an inverse hyperbolic tangent function to each component of the intermediate control vector to obtain a calculation result; The calculation result is output to the actuator to drive the control surface and the motor.

5. The method for controlling a drone based on a random key stream according to claim 3, wherein: After the hyperbolic tangent function is used to approximate the saturation constraint, the method further includes: Calculating an approximation error between an output value of the hyperbolic tangent function and a saturation constraint, and estimating an upper bound of the approximation error; The upper bound is injected into the state feedback control law to obtain a compensation gain, and the compensation gain is adaptively adjusted.

6. The method for controlling a drone based on a random key stream according to claim 4, characterized in that: The method further comprises: When the number of consecutive decryption failures exceeds a threshold, the current control instruction is frozen; Switch to the preset gain matrix and calculate conservative control instructions according to the preset gain matrix.

7. A drone control device based on random key stream, characterized in that: The device comprises: at least one processor; and, a memory communicatively coupled to the at least one processor; The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least a processor to execute so that the at least one processor is capable of: Execute the steps of a drone control method based on random key stream as described in any one of claims 1-6.

8. A non-volatile computer storage medium for drone control based on a random key stream, storing computer-executable instructions, characterized in that: The computer executable instructions are configured to: Execute the steps of a drone control method based on random key stream as described in any one of claims 1-6.

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