Cluster aircraft semi-physical simulation system based on Pixhawk flight control

Abstract

The invention provides a Pixhawk flight control-based cluster aircraft semi-physical simulation system. The Pixhawk flight control-based cluster aircraft semi-physical simulation system comprises an airborne computer, a Pixhawk flight controller, an unmanned aerial vehicle networking communication module, a simulation machine and an AirSim simulation environment. The airborne computer is used for collecting and processing sensor data on the aircraft; the unmanned aerial vehicle networking communication module is used for distributed wireless signal transmission; the Pixhawk flight controller is used for autonomously executing a pre-planned flight task through a built-in flight control algorithm; and the simulator and the AirSim simulation environment are used for providing an accurate semi-physical simulation environment and verifying the flight effect through visual simulation. According to the semi-physical simulation system, a real physical model and a simulation environment can be combined, and the confidence coefficient of the system is improved by reducing errors; the operation condition of the distributed cluster aircraft is simulated through collaborative networking, and the research and development efficiency of the distributed cluster aircraft control system is improved.

Description

Technical Field

[0001] The present application relates to the construction of a semi-physical simulation platform for distributed swarm aircraft, and in particular to a semi-physical simulation system for swarm aircraft based on Pixhawk flight control. Background Art

[0002] Distributed swarm aircraft refers to a group of multiple drones. With the rapid development of drone technology, swarm aircraft have shown broad application prospects in the fields of military, security, rescue, aviation monitoring, logistics and distribution. These swarm aircraft can coordinate with each other through distributed control algorithms to complete tasks together. Distributed control algorithms do not have a central point of system control. They exchange information through mutual coordination between adjacent aircraft and finally complete the overall formation planning. This control method can significantly improve the efficiency, flexibility and safety of task execution, while reducing the demand and risk of human resources.

[0003] However, traditional aircraft simulation systems mainly use software such as Simulink, which cannot be combined with real flight control and are difficult to simulate the operation of aircraft in actual environments. Moreover, in the research on large-scale drone clusters, there is a lack of development of simulation systems under collaborative networking conditions. They are limited to information transmission between adjacent aircraft, rather than wireless communication between all aircraft. As a result, problems that may exist in actual flight cannot be reflected in the simulation, which makes it difficult to conduct in-depth research on distributed cluster aircraft.

[0004] In view of the characteristics of distributed cluster aircraft, such as short relative distance between modules, short signal delay and strong signal strength, the MAVLink communication protocol can be used to realize wireless information transmission of distributed cluster aircraft. In view of the difficulty in actual flight verification of cluster aircraft under collaborative networking, a semi-physical simulation system of cluster aircraft based on Pixhawk flight control can be built to simulate the formation control of distributed cluster aircraft. Summary of the invention

[0005] In response to the above problems and technical requirements, the applicant proposed a semi-physical simulation system for cluster aircraft based on Pixhawk flight control. The main technical solutions adopted in this application are as follows:

[0006] The semi-physical simulation system of cluster aircraft based on Pixhawk flight control includes:

[0007] Onboard computer, Pixhawk flight controller, drone networking communication module, simulator and AirSim simulation environment.

[0008] S1, the onboard computer is used to collect and package sensor data on the aircraft for use by the flight control algorithm, and to establish a network communication connection with other onboard computers;

[0009] S2, the UAV networking communication module is used to synchronize information and share sensor data between multiple aircraft through distributed wireless signal transmission, and transmit data information to each Pixhawk flight controller to achieve cluster control;

[0010] S3, the Pixhawk flight controller is used to exchange real-time data through UAV networking communication, autonomously execute pre-planned flight missions through built-in flight control algorithms, and reflect the aircraft operation status on the simulator by connecting to the simulator and the AirSim simulation environment to verify the predetermined flight control effect;

[0011] S4, the simulator and the AirSim simulation environment are used to provide an accurate semi-physical visual simulation environment to verify and test the flight control algorithm in the Pixhawk flight controller by simulating multiple sensors and a real flight environment.

[0012] Furthermore, the onboard computer collects position, speed, and attitude information from sensors on the aircraft, and transmits the information to the flight control algorithm for calculation.

[0013] Furthermore, the UAV networking communication module is used to ensure that each aircraft can simultaneously obtain the position, speed, and attitude information of all other aircraft while determining its own information, share the collected data with each other, and transmit task information; through the UAV networking communication module, the simulator issues task instructions, assigns tasks to each aircraft, and monitors the progress of task execution.

[0014] Furthermore, the Pixhawk flight controller integrates different types of sensors, including a three-axis gyroscope, a three-axis accelerometer, a three-axis magnetometer, a barometer, and a GPS module. By synthesizing and optimizing the data provided by the sensors, the attitude, position, and speed information of the aircraft are obtained.

[0015] Furthermore, the Pixhawk flight controller has a built-in PID controller, which enables it to fly in the expected manner; and allows users to pre-plan through ground station software, including setting take-off points, waypoints and landing points, and autonomously execute pre-planned flight missions according to the settings.

[0016] Furthermore, the flight control algorithm in the Pixhawk flight control mainly uses a quaternion-based hierarchical PID controller to manage the attitude and position of the aircraft. The MC_ATT_CONTROL module is used to implement the attitude control algorithm, including inner and outer loop PID control, outer loop control angle, inner loop control angular velocity; the MC_POS_CONTROL module is used to implement the position control algorithm, also using inner and outer loop PID control, outer loop control speed, inner loop control acceleration.

[0017] Furthermore, the simulator and AirSim simulation environment are used to provide a virtual 3D environment, which is combined with a real hardware system to simulate real flight conditions including terrain, weather, and lighting factors. By simulating various conditions in the real environment, the control effect of the above-mentioned flight control algorithm under different conditions is evaluated, and the operation status of each aircraft is displayed in real time and intuitively through the simulator screen.

[0018] Furthermore, the system connects various hardware devices and communication modules to network and communicate multiple aircraft and simulators. The specific process is as follows: in the simulator, the settings.json file automatically generated after installing the AirSim simulation environment is stored in the AirSim directory, all Pixhawk flight controllers are connected to the simulator via a USB-hub using USB cables, and the corresponding com port number is filled in the settings.json file; according to the connection sequence of the serial ports, the Pixhawk and the airborne computer are connected through the Telem 2 port of the Pixhawk flight controller, and the airborne computer and the router are connected through the network port to form a drone networking communication module, and each communication module is powered on in turn to network, and after waiting for the airborne computer to automatically communicate with the simulator, the commander command and the above-mentioned flight control algorithm are run, wherein the commander command is used to process the code of the entire control mode, and the flight control algorithm is used to ensure the stable flight of the drone and the execution of the predetermined task.

[0019] Furthermore, the operation of the system is as follows: after the cluster aircraft is networked, it unlocks and takes off by receiving external commands, and then switches the aircraft to idle mode; after giving external control information, the onboard computer first obtains the corresponding path planning algorithm through the cluster algorithm and networking communication function, and then transmits it to the Pixhawk flight control, and drives the aircraft by running the commander command and the above-mentioned flight control algorithm, so that the cluster aircraft performs formation flight missions according to given requirements and displays flight trajectory information in the simulator.

[0020] The beneficial technical effects of this application are:

[0021] The present application discloses a semi-physical simulation system for cluster aircraft based on Pixhawk flight control. The system combines digital simulation and actual hardware, can more accurately simulate the dynamic behavior and environmental interaction of aircraft, provide a test environment close to real flight conditions, reduce the error between the virtual system and the real equipment, and improve the confidence of the simulation; the use of Pixhawk flight control ensures the operation effect of the control algorithm on the actual hardware, enhances the real-time and reliability of the simulation; the wireless communication function of the UAV networking communication module ensures that all aircraft can share information in real time, and each aircraft completes the task independently, thereby realizing large-scale cluster formation under distributed control; the system can provide a safe experimental platform while controlling costs, and improve the efficiency of flight control algorithm development and optimization through multiple simulations and tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is an overall display diagram of the semi-physical simulation system of cluster aircraft based on Pixhawk flight control;

[0023] Figure 2 This is the structural block diagram of the semi-physical simulation system of cluster aircraft based on Pixhawk flight control;

[0024] Figure 3 This is the workflow diagram of the semi-physical simulation system of cluster aircraft based on Pixhawk flight control;

[0025] Figure 4 This is the flow chart of the connection between the simulator and the flight control part;

[0026] Figure 5 This is the internal structure diagram of a single flight control system based on the Pixhawk flight control and onboard computer;

[0027] Figure 6 It is the algorithm logic diagram of distributed cluster aircraft;

[0028] Figure 7 It is a communication connection diagram for the coordinated networking and information interaction of distributed cluster aircraft;

[0029] Figure 8 It is the topological structure of the distributed cluster aircraft system network;

[0030] Fig. 9 This is a diagram of the distributed cluster aircraft simulator and the AirSim simulation environment interface. DETAILED DESCRIPTION

[0031] The specific implementation of the present application is further described below in conjunction with the accompanying drawings.

[0032] In response to the problems mentioned in the background technology, this application designs a semi-physical simulation system for cluster aircraft based on Pixhawk flight control, taking into account efficiency, economy and safety. By combining the advanced functions of Pixhawk flight control and semi-physical simulation technology, the error between the virtual system and the real equipment is reduced, and the software and hardware of the flight control can be verified without a test flight, which improves the confidence of the simulation and makes the simulation results closer to the performance under real flight conditions. It can also simulate the flight trajectory of the aircraft in real time and intuitively, thereby significantly reducing experimental costs and risks.

[0033] This application discloses a semi-physical simulation system for cluster aircraft based on Pixhawk flight control. Figure 1 ,In general, the entire system includes an onboard computer, Pixhawk flight controller, UAV networking ,communication module, simulator and AirSim simulation environment.

[0034] The semi-physical simulation system of cluster aircraft based on Pixhawk flight control in this application includes:

[0035] Onboard computer, Pixhawk flight controller, drone networking communication module, simulator and AirSim simulation environment;

[0036] The onboard computer is used to collect and package sensor data on the aircraft for use by the flight control algorithm and to establish a network communication connection with other onboard computers;

[0037] The UAV networking communication module is used to synchronize information and share sensor data between multiple aircraft through distributed wireless signal transmission, and transmit data information to each Pixhawk flight controller to achieve cluster control;

[0038] The Pixhawk flight controller is used to exchange real-time data through UAV networking communication, autonomously execute pre-planned flight missions through built-in flight control algorithms, and reflect the aircraft operation status to the simulator by connecting to the simulator and the AirSim simulation environment to verify the predetermined flight control effect; the system performs networking communication for multiple aircraft and simulators by connecting various hardware devices and communication modules;

[0039] The simulator and AirSim simulation environment are used to provide an accurate semi-physical visual simulation environment to verify and test the flight control algorithm in the Pixhawk flight controller by simulating multiple sensors and a real flight environment.

[0040] The onboard computer collects position, speed, and attitude information from sensors on the aircraft and transmits the information to the flight control algorithm for calculation.

[0041] The UAV networking communication module is used to ensure that each aircraft can simultaneously obtain the position, speed, and attitude information of all other aircraft while determining its own information, share the collected data with each other, and transmit task information; the simulator issues task instructions through the UAV networking communication module, assigns tasks to each aircraft, and monitors the progress of task execution.

[0042] The Pixhawk flight controller integrates different types of sensors, including a three-axis gyroscope, a three-axis accelerometer, a three-axis magnetometer, a barometer, and a GPS module. The attitude, position, and speed information of the aircraft are obtained by synthesizing and optimizing the data provided by the sensors.

[0043] The Pixhawk flight controller has a built-in PID controller, which enables it to fly in the expected manner; and allows users to pre-plan through the ground station software, including setting the take-off point, waypoints and landing points, and autonomously execute pre-planned flight missions according to the settings.

[0044] The Pixhawk flight controller is embedded in the PX4 firmware, and the flight control algorithm is integrated in the PX4 firmware. The flight control algorithm uses a PID controller based on a quaternion hierarchical structure to manage the attitude and position of the aircraft; the quaternion hierarchical structure PID controller includes the quaternion hierarchical structure PID controller includes the MC_ATT_CONTROL module, and the MC_ATT_CONTROL module is used for the algorithm implementation of attitude control, including inner and outer loop PID control, outer loop control angle, and inner loop control angular velocity; the MC_POS_CONTROL module is used for the algorithm implementation of position control, which also adopts inner and outer loop PID control, outer loop control speed, and inner loop control acceleration.

[0045] The simulator and AirSim simulation environment are used to provide a virtual 3D environment, which is combined with the real hardware system to simulate real flight conditions including terrain, weather, and lighting factors. By simulating various conditions in the real environment, the control effect under different conditions is evaluated, and the operation status of each aircraft is displayed in real time and intuitively through the simulator screen.

[0046] The system connects various hardware devices and communication modules to network and communicate multiple aircrafts and simulators. The specific process is as follows: on the simulator, the settings.json file in the AirSim simulation environment is stored in the AirSim directory, all Pixhawk flight controllers are connected to the simulator via a USB-hub using USB cables, and the corresponding com port number is added to the settings.json file; according to the connection sequence of the serial ports, the Pixhawk and the airborne computer are connected via the Telem 2 port of the Pixhawk flight controller, and the airborne computer and the router are connected via the network port to form a UAV networking communication module, and each communication module is powered on in turn to network, and after waiting for the airborne computer to automatically network and communicate with the simulator, the commander command and the flight control algorithm are run, wherein the commander command is used to process the code of the entire control mode.

[0047] The operation of the system is as follows: after the cluster aircraft is networked, it unlocks and takes off by receiving external commands, and then switches the aircraft to idle mode; after giving external control information, the onboard computer first obtains the corresponding path planning algorithm through the cluster algorithm and networking communication function, and then transmits it to the Pixhawk flight control, and drives the aircraft by running the commander command and the flight control algorithm, so that the cluster aircraft performs formation flight missions according to given requirements and displays flight trajectory information in the simulator.

[0048] The structural block diagram of the semi-physical simulation system of cluster aircraft based on Pixhawk flight control is as follows: Figure 2 As shown. The simulator adds interfaces through the USB expansion dock to connect various flight control units, including the Pixhawk flight control and the onboard computer. The flight control units are networked through the MAVLink communication protocol to share location data and mission information. When a mission instruction is issued, the Pixhawk flight control and the onboard computer process the data and implement path planning through the corresponding flight control algorithm, and intuitively display the flight status of the cluster aircraft in the real-time simulator and AirSim simulation environment.

[0049] The workflow diagram for building a semi-physical simulation system for cluster aircraft based on Pixhawk flight control is as follows: Figure 3 As shown. First, the simulator is turned on, and the hardware devices and communication modules are connected and started. The aircraft are networked to share speed and position status information, and control instructions are sent to the Pixhawk flight controller through the MAVLink communication protocol. The Pixhawk flight controller and the onboard computer process data, implement path planning and task allocation based on the synchronization information obtained by the collaborative network, and control the operation of the cluster aircraft. The flight status of the cluster aircraft is intuitively displayed in the real-time simulator and AirSim simulation environment.

[0050] Build a semi-physical simulation system for cluster aircraft based on Pixhawk flight control. Figure 4 This is a flow chart of the connection between the simulator and the flight control unit. The simulator can add an interface through the USB expansion dock, which can be connected to multiple flight control units to achieve the collaborative networking of distributed cluster aircraft.

[0051] To build a single flight control system, each flight control system consists of a Pixhawk flight control and an onboard computer connected via a serial port, and connected to a router via an Ethernet port to achieve communication. Figure 5 This is a diagram of the internal structure of a single flight control system based on the Pixhawk flight control and the onboard computer. The controller parameters of the outer and inner loops of the remaining flight control are set to the default values. Figure 6 This is the algorithm logic diagram of the distributed cluster aircraft. Among them, the flight control algorithm is mainly provided by the Pixhawk flight control. The position control can be controlled remotely by a computer or autonomous flight trajectory planning can be performed; the attitude control is adjusted in real time by the flight control system. In the Pixhawk flight control, the outer loop position control and the inner loop attitude control simultaneously introduce the PID link to realize cascade PID control. The PID controller compares the given value r(t) with the actual output value y(t) to obtain the input error. At the same time, the error is used as input to continuously adjust the output y(t). The input error is as follows:

[0052] e(t)=r(t)-y(t);

[0053] Among them, e(t) is the input error; by performing proportional, integral, and differential operations on the input error e(t), the expression of the control quantity u(t) can be obtained as follows:

[0054]

[0055] Among them, K P is the proportionality coefficient, K I is the integration coefficient, K D is the differential coefficient; in the aircraft cascade PID control, the real-time position of the aircraft is controlled by the position loop, and the real-time attitude is controlled by the attitude loop. For the outer loop position PID control, the following relationship can be established:

[0056]

[0057] Among them, K p ,K i ,K d They are proportional, integral, and differential adjustment coefficients in PID respectively; x, y, and z are the given desired positions, x f ,y f ,z f is the actual location; The first derivative of the given desired position, representing the given desired velocity, The first derivative of the actual position, representing the actual velocity; for the inner-loop angle PID control, the input-output relationship can be constructed in the same way as the outer loop. Based on the aircraft dynamics modeling, the attitude calculation module can be obtained as follows:

[0058]

[0059] where, is the second derivative of the position, i.e., the acceleration in the three-axis directions; φ, θ, ψ are the roll angle, pitch angle, and yaw angle respectively; is the first derivative of the three attitude angles, i.e., the angular velocity about the three axes; is the second derivative of the three attitude angles, i.e., the angular acceleration about the three axes; U1 is the total lift of the rotor, U2 is the roll torque, U3 is the pitch torque, U4 is the yaw torque; m is the mass of the aircraft, g is the acceleration due to gravity; I x , I y , I z are the moments of inertia about the three axes; through the calculation module, the corresponding attitude angles can be calculated and used as the input of the attitude-loop PID controller. Based on the inverse calculation of the above system model, the attitude equations can be obtained as follows:

[0060]

[0061] In the aircraft attitude-loop PID controller, the input is the difference between the attitude angles calculated by the calculation module and the current attitude angles, and the output is the input variables of the aircraft system model. Through the aircraft system model, the real-time attitude angles are fed back into the attitude loop, and the velocity integral is fed back into the position loop.

[0062] Build the communication network structure for the collaborative networking of distributed cluster aircraft. Each aircraft has a number, and the aircrafts collaborate and network through communication connections. In terms of the network structure, the system networks through the 5GHz network band of the local area network. At the same time, the communication module also supports the network signals of the 2.4GHz band; the frequency range used in this simulation is 5GHz, with an effective transmission range of 500m, which can provide faster data transmission rate and less interference; in terms of hardware, the bridge of the first aircraft acts as a router to network the devices of the other aircrafts including the commander. The maximum number of devices that can be supported online in the network is 127; in terms of the ipv4 address allocation relationship of each device in the local area network, the IP address of the nth aircraft is: 192.168.100.n (0 < n < 127), and the IP address of the communication bridge of the nth aircraft is: 192.168.100.(255 - n), and the gateway is set to the IP address of the first aircraft. Figure 7This is a communication connection diagram for the collaborative networking and information interaction of distributed cluster aircraft.

[0063] The communication module for building a collaborative network of distributed cluster aircraft is mainly based on the nanomsg library. nanomsg is a lightweight network communication library that provides a set of advanced socket types that can easily build distributed network applications. The communication process established in this simulation is as follows: first, the information that the aircraft needs to send is serialized, and then sent using the nanomsg library. At the receiving end, the message is reconstructed using its prescribed deserialization method, thereby realizing communication between different nodes in the local area network. The characteristic of the nanomsg library is that it supports the bus mode, namely BUS, which is similar to a network-based shared memory space, allowing point-to-point communication between any number of nodes, and there is no single control node, and all nodes have equal status. Therefore, in the bus mode, each aircraft communicates with all other aircraft connected to the same bus, and can send information to each other, which is particularly suitable for communication between distributed cluster aircraft.

[0064] The topological structure of the distributed cluster aircraft system network is as follows: Figure 8 As shown. The wireless router establishes a wireless network, and each aircraft and PC display terminal are connected to the wireless network. In the distributed cluster aircraft semi-physical simulation system, the communication between each aircraft uses the MAVLink communication protocol to transmit information wirelessly in real time. The MAVLink communication protocol is a very lightweight message transmission protocol designed for the drone ecosystem. After the wireless module is configured and powered on, it first enters the network idle state; when the communication process begins, a request or negotiation process is completed between the simulator and the aircraft through the wireless router to establish a communication channel; after the networking communication process is completed, the communication channel is released and the network returns to the idle state. Such a network topology has great flexibility and scalability. The topology of the entire network is not fixed, but changes all the time according to the needs of data transmission, which can well solve the networking communication problem when the positions and attitudes of multiple aircraft change dynamically.

[0065] The specific simulation process of building a distributed swarm aircraft is that the networked aircraft receives external commands and responds accordingly: first, the external command machine sends a message to the swarm aircraft to unlock and take off; second, the aircraft is switched to idle mode; then, the aircraft can receive external information and fly from a random point on the ground to a specified position on the aircraft's NED coordinate system. It can be seen in the simulator and the AirSim simulation environment that the swarm aircraft always maintains a fixed lateral expected distance and expected formation mode during flight, such as a straight-line formation, etc. The swarm aircraft can fly directly to the corresponding position according to external information requirements and display the flight trajectory in the simulator. Fig. 9 This is a diagram of the distributed cluster aircraft simulator and the AirSim simulation environment interface.

[0066] In summary, the semi-physical simulation system of distributed cluster aircraft based on Pixhawk flight control has the characteristics of high confidence. It combines digital simulation and actual hardware, can more accurately simulate the dynamic behavior and environmental interaction of aircraft, provide a test environment close to real flight conditions, reduce the error between the virtual system and the real equipment, and improve the confidence of the simulation. It can effectively realize the collaborative networking and flight control of distributed cluster aircraft based on Pixhawk flight control, and intuitively display the trajectory of cluster aircraft during formation flight, accurately simulate the dynamic behavior of aircraft under close to real flight conditions; the use of Pixhawk flight control ensures the operation effect of the control algorithm on actual hardware, and enhances the real-time and reliability of the simulation; the system can provide a safe experimental platform while controlling costs, and improve the efficiency of flight control algorithm development and optimization through multiple simulations and tests.

[0067] It can be understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the scope of protection of the present application.

Claims

1. A semi-physical simulation system for cluster aircraft based on Pixhawk flight control, characterized by: include: Onboard computer, Pixhawk flight controller, drone networking communication module, simulator and AirSim simulation environment; The onboard computer is used to collect and package sensor data on the aircraft for use by the flight control algorithm and to establish a network communication connection with other onboard computers; The UAV networking communication module is used to synchronize information and share sensor data between multiple aircraft through distributed wireless signal transmission, and transmit data information to each Pixhawk flight controller to achieve cluster control; The Pixhawk flight controller is used to exchange real-time data through UAV networking communication, autonomously execute pre-planned flight missions through built-in flight control algorithms, and reflect the aircraft operation status to the simulator by connecting to the simulator and the AirSim simulation environment to verify the predetermined flight control effect; the system performs networking communication for multiple aircraft and simulators by connecting various hardware devices and communication modules; The simulator and AirSim simulation environment are used to provide an accurate semi-physical visual simulation environment to verify and test the flight control algorithm in the Pixhawk flight controller by simulating multiple sensors and a real flight environment.

2. The semi-physical simulation system for cluster aircraft based on Pixhawk flight control according to claim 1, characterized in that: The onboard computer collects position, speed, and attitude information from sensors on the aircraft and transmits the information to the flight control algorithm for calculation.

3. The semi-physical simulation system for cluster aircraft based on Pixhawk flight control according to claim 1, characterized in that: The UAV networking communication module is used to ensure that each aircraft can simultaneously obtain the position, speed, and attitude information of all other aircraft while determining its own information, share the collected data with each other, and transmit task information; the simulator issues task instructions through the UAV networking communication module, assigns tasks to each aircraft, and monitors the progress of task execution.

4. The semi-physical simulation system for cluster aircraft based on Pixhawk flight control according to claim 1, characterized in that: The Pixhawk flight controller integrates different types of sensors, including a three-axis gyroscope, a three-axis accelerometer, a three-axis magnetometer, a barometer, and a GPS module. The attitude, position, and speed information of the aircraft are obtained by synthesizing and optimizing the data provided by the sensors.

5. The semi-physical simulation system for cluster aircraft based on Pixhawk flight control according to claim 4, characterized in that: The Pixhawk flight controller has a built-in PID controller, which enables it to fly in the expected manner; and allows users to pre-plan through the ground station software, including setting the take-off point, waypoints and landing points, and autonomously execute pre-planned flight missions according to the settings.

6. The semi-physical simulation system for cluster aircraft based on Pixhawk flight control according to claim 5, characterized in that: The Pixhawk flight controller is embedded in the PX4 firmware, and the flight control algorithm is integrated in the PX4 firmware. The flight control algorithm uses a PID controller based on a quaternion hierarchical structure to manage the attitude and position of the aircraft; the quaternion hierarchical structure PID controller includes the quaternion hierarchical structure PID controller includes the MC_ATT_CONTROL module, and the MC_ATT_CONTROL module is used for the algorithm implementation of attitude control, including inner and outer loop PID control, outer loop control angle, and inner loop control angular velocity; the MC_POS_CONTROL module is used for the algorithm implementation of position control, which also adopts inner and outer loop PID control, outer loop control speed, and inner loop control acceleration.

7. The semi-physical simulation system for cluster aircraft based on Pixhawk flight control according to claim 1, characterized in that: The simulator and AirSim simulation environment are used to provide a virtual 3D environment, which is combined with the real hardware system to simulate real flight conditions including terrain, weather, and lighting factors. By simulating various conditions in the real environment, the control effect under different conditions is evaluated, and the operation status of each aircraft is displayed in real time and intuitively through the simulator screen.

8. The semi-physical simulation system for cluster aircraft based on Pixhawk flight control according to claim 1, characterized in that: The system connects various hardware devices and communication modules to network and communicate multiple aircrafts and simulators. The specific process is as follows: on the simulator, the settings.json file in the AirSim simulation environment is stored in the AirSim directory, all Pixhawk flight controllers are connected to the simulator via a USB-hub using USB cables, and the corresponding com port number is added to the settings.json file; according to the connection sequence of the serial ports, the Pixhawk and the airborne computer are connected via the Telem 2 port of the Pixhawk flight controller, and the airborne computer and the router are connected via the network port to form a UAV networking communication module, and each communication module is powered on in turn to network, and after waiting for the airborne computer to automatically network and communicate with the simulator, the commander command and the flight control algorithm are run, wherein the commander command is used to process the code of the entire control mode.

9. The semi-physical simulation system for cluster aircraft based on Pixhawk flight control according to claim 1, characterized in that: The operation of the system is as follows: after the cluster aircraft is networked, it unlocks and takes off by receiving external commands, and then switches the aircraft to idle mode; after giving external control information, the onboard computer first obtains the corresponding path planning algorithm through the cluster algorithm and networking communication function, and then transmits it to the Pixhawk flight control, and drives the aircraft by running the commander command and the flight control algorithm, so that the cluster aircraft performs formation flight missions according to given requirements and displays flight trajectory information in the simulator.

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