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Drones are increasingly widely used in both civilian and military fields, and their development has attracted attention from various countries. The role of trajectory tracking control in the flight process of drones is particularly important, which can further improve their dynamic performance and provide strong support for drones to complete various tasks safely and efficiently.
The rapid development of drones has only a few decades of history. First, the United States used drones as target planes for training during the Vietnam War, and later used drones to take photos and scout Ho Chi Minh Trail. In the 1982 Lebanon War, Israel used drones for practical combat and used military drones for firepower reconnaissance. Later on, in the
During the Gulf War, the United States began to extensively use drones, mainly as reconnaissance aircraft, electronic jammers, artillery target guidance aircraft, and target aircraft. In recent years, the US military has started using drones to attack terrorist convoys in Afghanistan, and has achieved great results. Several senior Taliban officers have died in the attacks.
More than 50 types of drones have been developed in 32 countries around the world, and 55 countries are equipped with drones. In the development of unmanned aerial vehicles, the United States is at the forefront and has developed validation aircraft for the Air Force and Navy. Boeing is one of the major drone manufacturers in the United States. Since the beginning of the 21st century, with the development of a new type of unmanned aerial vehicle - unmanned combat aircraft, drones will no longer be the main auxiliary role on the battlefield in the past. In the past, drones were mainly used for aerial reconnaissance, battlefield monitoring, and combat damage assessment tasks, upgraded to be able to execute air defense systems, ground attacks, and even air combat missions. Drones will not only collaborate and fight alongside manned fighter jets on future battlefields, but may also replace manned fighter jets in dangerous combat tasks under certain conditions, potentially becoming the main aviation weapon equipment for future air combat. The emergence of unmanned combat aircraft has significant strategic significance and may lead to significant changes in the organization, principles, regulations, tactical thinking, and equipment procurement strategies of future air operations.
1. Task centered design without considering human factors.
2. The structure of the drone itself is simple, but the system is complex.
3. Drones can operate in hazardous environments.
The cost of using drones is relatively low.
5. Drones have strong endurance.
6. Zero casualties.
Generally speaking, the performance and flight quality of drones are determined by their aerodynamic and engine characteristics. But as the altitude and speed of drones increase, their own characteristics will deteriorate. When a drone is flying at high altitude, due to the thin air, its damping characteristics deteriorate, causing serious oscillation in its angular motion. In addition, when designing a drone, in order to reduce mass and drag, and improve lift, it is often designed as statically unstable. Therefore, for such statically unstable drones, different types of control systems need to be installed to change their performance.
In this way, how to adjust the flight control system of the drone to better and faster track the predetermined trajectory, that is, design the flight control system through the establishment of the drone model, and then study the trajectory tracking control of the drone, is of great significance for improving the overall performance of the drone and the development of the aviation industry.
The six degree of freedom nonlinear aircraft equation is used as the model, and the error between the command signal and the actual state is solved by solving the guidance force, which is then converted into command signals such as angle of attack α, sideslip angle β, trajectory roll angle μ, and thrust T as input commands for the attitude loop. The attitude control system adopts a mature dynamic inversion method to design fast and slow inversion loops, which can meet the requirements of maneuvering flight.
The ultimate goal of flight path tracking control is to enable the aircraft to maintain or track the predetermined flight path with sufficient accuracy. The system that controls the movement and trajectory of an aircraft is called a guidance system. If the aircraft deviates from the given trajectory, the guidance device will measure its deviation and control the angular motion according to a certain control law, so that the aircraft can return to the given trajectory with the required accuracy. The center of gravity movement of an aircraft can be divided into three types: vertical, tangential, and lateral deviation. Lateral deviation is usually corrected by the aircraft tilting and turning, and sideslip is generally not desired. Lateral deviation control is based on the control of roll angle. The deviation in the vertical direction is corrected by controlling the angle of attack. The deviation from the tangent direction of the flight path is corrected by controlling the engine to change thrust and speed. Guidance force consists of two parts, one of which is the force required for the aircraft to perform the desired maneuver. The other part is the force required to eliminate guidance errors, including position errors, velocity errors, and horizontal and vertical trajectory angle errors.
The controller can also adopt PID control, including classical PID control and intelligent control developed in recent years. The classic PID control is widely used in unmanned aerial vehicle control systems due to its simple algorithm, easy implementation, and high reliability. But with the discipline of artificial intelligence
With the development of intelligent control, it has become increasingly popular in practical control systems and has become a new direction for control development. And by combining the methods of artificial intelligence with traditional PID, taking their respective advantages, a new PID controller is formed, which greatly improves the performance of traditional PID control.
Drone development
Unmanned Aerial Vehicle (UAV), also known as unmanned aerial vehicle or remote-controlled aircraft, is a type of unmanned aerial vehicle controlled by radio remote control equipment or pre programmed control. It has many advantages that manned aircraft do not have, and can perform various tasks such as combat and training support, with broad military application prospects.The rapid development of drones has only a few decades of history. First, the United States used drones as target planes for training during the Vietnam War, and later used drones to take photos and scout Ho Chi Minh Trail. In the 1982 Lebanon War, Israel used drones for practical combat and used military drones for firepower reconnaissance. Later on, in the
During the Gulf War, the United States began to extensively use drones, mainly as reconnaissance aircraft, electronic jammers, artillery target guidance aircraft, and target aircraft. In recent years, the US military has started using drones to attack terrorist convoys in Afghanistan, and has achieved great results. Several senior Taliban officers have died in the attacks.
More than 50 types of drones have been developed in 32 countries around the world, and 55 countries are equipped with drones. In the development of unmanned aerial vehicles, the United States is at the forefront and has developed validation aircraft for the Air Force and Navy. Boeing is one of the major drone manufacturers in the United States. Since the beginning of the 21st century, with the development of a new type of unmanned aerial vehicle - unmanned combat aircraft, drones will no longer be the main auxiliary role on the battlefield in the past. In the past, drones were mainly used for aerial reconnaissance, battlefield monitoring, and combat damage assessment tasks, upgraded to be able to execute air defense systems, ground attacks, and even air combat missions. Drones will not only collaborate and fight alongside manned fighter jets on future battlefields, but may also replace manned fighter jets in dangerous combat tasks under certain conditions, potentially becoming the main aviation weapon equipment for future air combat. The emergence of unmanned combat aircraft has significant strategic significance and may lead to significant changes in the organization, principles, regulations, tactical thinking, and equipment procurement strategies of future air operations.
The characteristics of drones
Manned fighter jets, attack planes, etc. are the main forces in aerial combat and enemy attacks. With the rapid development of air combat weapons and integrated air defense systems, relying solely on manned aircraft to carry out aerial combat and ground attack missions in the future battlefield will entail greater risks and higher costs, and war losses and political risks will become increasingly difficult to bear. To this end, countries around the world have begun to study and evaluate the military effectiveness and practical value of drones on the battlefield, and have invested heavily in exploring various solutions and developing various types of unmanned combat aircraft. Unmanned combat aircraft have the following characteristics:1. Task centered design without considering human factors.
2. The structure of the drone itself is simple, but the system is complex.
3. Drones can operate in hazardous environments.
The cost of using drones is relatively low.
5. Drones have strong endurance.
6. Zero casualties.
Development of Track Tracking Control Systems
The trajectory tracking control of drones is mainly achieved through the flight control system of drones. The reason why drones can play such a huge role is not only because they have made significant breakthroughs in aerodynamics, structure, and engines, but also because it is crucial to install flight control systems with various functions on drones. Flight control systems are generally composed of subsystems or components with different functions, which can control the center of gravity (trajectory motion), angular motion, and flight speed of unmanned aerial vehicles, and improve the flight quality and ensure the flight safety of unmanned aerial vehicles. Its basic function is to achieve automatic flight of drones and improve their dynamic performance.Generally speaking, the performance and flight quality of drones are determined by their aerodynamic and engine characteristics. But as the altitude and speed of drones increase, their own characteristics will deteriorate. When a drone is flying at high altitude, due to the thin air, its damping characteristics deteriorate, causing serious oscillation in its angular motion. In addition, when designing a drone, in order to reduce mass and drag, and improve lift, it is often designed as statically unstable. Therefore, for such statically unstable drones, different types of control systems need to be installed to change their performance.
In this way, how to adjust the flight control system of the drone to better and faster track the predetermined trajectory, that is, design the flight control system through the establishment of the drone model, and then study the trajectory tracking control of the drone, is of great significance for improving the overall performance of the drone and the development of the aviation industry.
Overall structure of the controller
On the basis of in-depth understanding and research on existing advanced flight control technologies, and considering the characteristics and functional requirements of unmanned aerial vehicles, a maneuvering trajectory tracking control scheme is proposed, with guidance and attitude control designed separately as shown in Figure 1.The six degree of freedom nonlinear aircraft equation is used as the model, and the error between the command signal and the actual state is solved by solving the guidance force, which is then converted into command signals such as angle of attack α, sideslip angle β, trajectory roll angle μ, and thrust T as input commands for the attitude loop. The attitude control system adopts a mature dynamic inversion method to design fast and slow inversion loops, which can meet the requirements of maneuvering flight.
The ultimate goal of flight path tracking control is to enable the aircraft to maintain or track the predetermined flight path with sufficient accuracy. The system that controls the movement and trajectory of an aircraft is called a guidance system. If the aircraft deviates from the given trajectory, the guidance device will measure its deviation and control the angular motion according to a certain control law, so that the aircraft can return to the given trajectory with the required accuracy. The center of gravity movement of an aircraft can be divided into three types: vertical, tangential, and lateral deviation. Lateral deviation is usually corrected by the aircraft tilting and turning, and sideslip is generally not desired. Lateral deviation control is based on the control of roll angle. The deviation in the vertical direction is corrected by controlling the angle of attack. The deviation from the tangent direction of the flight path is corrected by controlling the engine to change thrust and speed. Guidance force consists of two parts, one of which is the force required for the aircraft to perform the desired maneuver. The other part is the force required to eliminate guidance errors, including position errors, velocity errors, and horizontal and vertical trajectory angle errors.
The controller can also adopt PID control, including classical PID control and intelligent control developed in recent years. The classic PID control is widely used in unmanned aerial vehicle control systems due to its simple algorithm, easy implementation, and high reliability. But with the discipline of artificial intelligence
With the development of intelligent control, it has become increasingly popular in practical control systems and has become a new direction for control development. And by combining the methods of artificial intelligence with traditional PID, taking their respective advantages, a new PID controller is formed, which greatly improves the performance of traditional PID control.
