CN114035448B - A semi-physical simulation system for UAV shipboard takeoff and landing based on physical domain model - Google Patents

Abstract

The invention discloses an unmanned aerial vehicle carrier-borne take-off and landing semi-physical simulation system based on a physical domain model, and belongs to the technical field of system simulation. The method specifically comprises the following steps: firstly, establishing a ship-based unmanned aerial vehicle model and a ship model, calculating the respective postures and positions, and sending the postures and positions to a flight control computer; the flight control computer obtains rudder quantity and throttle control quantity of the ship-based unmanned aerial vehicle model through calculation of a control law, and simultaneously sends the rudder quantity and the throttle control quantity to an X-Plane11 platform and a scaling machine; the X-Plane11 platform full-flow simulation ship-borne unmanned aerial vehicle model takes off, mode switching, hovering and landing processes; meanwhile, the scaling machine deflects the control surface according to the control quantity change and rotates the motor, so that the self dynamic state is kept the same as the dynamic state of the carrier-borne unmanned aerial vehicle model; the ground control station monitors the ship-based unmanned aerial vehicle model in real time. The method and the system can acquire the information of the relative position/speed/course/gesture and the like of the unmanned aerial vehicle and the ship in real time, so that the unmanned aerial vehicle can be controlled to fly more accurately.

Description

A semi-physical simulation system for UAV shipboard takeoff and landing based on physical domain model

Technical field

The invention belongs to the field of system simulation technology, and is specifically a semi-physical simulation system for shipboard takeoff and landing of an unmanned aerial vehicle based on a physical domain model.

Background technique

The drone industry has developed rapidly since the 21st century, and various types of drones have emerged one after another and are widely used in various scenarios. Ship-borne UAVs refer to UAVs that are based on surface ships, are controlled by shipboard personnel or complete the entire flight process in a fully autonomous manner, and can be reused. During maritime operations, ship-based UAVs can be used to perform preliminary aerial reconnaissance, intelligence collection, target tracking, relay communications, electronic countermeasures, mine detection and other tasks. They can also conduct anti-missile, anti-submarine and anti-ship operations. Very extensive. Compared with traditional manned carrier-based aircraft, carrier-based UAVs are smaller, more autonomous, have flexible combat capabilities, good stealth performance, can ignore the limits of the human body, and work all-weather in harsh environments such as high altitude oxygen deficiencies. It has the advantage of zero casualties and plays a vital role in the modern navy.

However, there are many difficulties in landing a ship-based UAV. When sailing at sea, due to the influence of sea wind and waves, it will sway in various directions, affecting the guidance accuracy. The space on the ship deck for the landing of ship-based drones is very limited, so the landing accuracy of ship-based drones is required to be very high.

As an indispensable means of complex engineering systems, semi-physical simulation can realize the simulation of human and hardware in the loop, and the simulation fidelity and credibility are relatively high, so it is crucial to the development of aircraft; in order to reduce development costs and reduce With small test flight risks, the development and design of a semi-physical flight simulation system for carrier-based UAVs is very urgent and important.

The existing document "Design and Implementation of Unmanned Helicopter Landing Control Simulation System" establishes a simulation system including flight simulation, three-dimensional vision and interface and simulation console modules, but this system is only targeted at unmanned helicopters. Ship information can only be obtained through an aircraft attached to the flight deck of the ship. In essence, it is not the real six-degree-of-freedom movement information of the ship. Synchronization between the drone and the ship can only be achieved through landscape sharing. The frame view does not run directly in the same simulation environment, and there is no flight control computer hardware and scaled prototype in the environment, which reduces the simulation effect of the ship-based UAV's takeoff and landing.

Contents of the invention

In response to the above problems, the present invention proposes a physical-in-the-loop simulation system for UAV shipboard takeoff and landing based on a physical domain model, realizing the design and construction of various types of UAV shipboard takeoff and landing semi-physical simulation systems.

The specific construction process of the semi-physical simulation system is as follows:

I), establish the carrier-based UAV model and ship model on the X-Plane11 platform, calculate the attitude and position of the ship-based UAV and ship through the surface element method and leaf element method, and send them to the flight control computer;

The data sent by the ship-based UAV model includes: the three-axis position, attitude angle, three-axis speed and three-axis acceleration of the UAV;

The data output by the ship model includes: the ship's course, position, speed, deck height, etc.;

II), the flight control computer obtains the rudder and throttle control quantities of the carrier-based UAV model through the calculation of the control law, and sends them to the X-Plane11 platform and scaled prototype at the same time;

The control law designs different control channels according to different models. Each control channel is divided into an inner loop and an outer loop. The inner loop completes attitude control; the outer loop completes position/speed control; both the inner and outer loops use cascade PID controllers;

The structure of the PID controller is as follows:

u(k)＝K(u _p (k)+u _i (k)+u _d (k))

Among them, u _p (k) is the proportional term of the PID controller, k _p1 is the gain of the first proportional link, e(k) is the error term, P _div is the error threshold of the proportional term, and k _p2 is the gain of the second proportional link. ;

u _i (k) is the integral term of the PID controller, k _i is the gain of the integral link, T is the time constant of the differential term, and ε is the error threshold of the integral term;

u _d (k) is the differential term of the PID controller, k _d is the gain of the differential link, and y(k) is the current value of the differential term;

u(k) is the control quantity of the PID controller, and K is the total coefficient.

Specifically, different carrier-based UAV models correspond to different control laws:

For quad-rotor models, the control law design includes longitudinal outer ring height control-inner ring pitch angle control; heading outer ring heading distance/speed control-inner ring course angle control; lateral outer ring lateral distance/speed control-inner ring roll angle control control;

For fixed-wing aircraft, the control law design includes longitudinal outer ring height-inner ring pitch angle control; heading horizontal position/heading control; lateral outer ring sideslip distance-inner ring roll angle control; and airspeed control;

For composite aircraft, corresponding to different flight modes, the control law is a combination of quad-rotor aircraft and fixed-wing aircraft;

For helicopter models, the control law design includes longitudinal outer ring height control-inner ring pitch angle control; heading outer ring heading distance/speed control-inner ring course angle control; lateral outer ring lateral distance/speed control-inner ring roll angle control ;

III), the X-Plane11 platform simulates the entire process of takeoff, mode switching, circling and landing according to the rudder amount and throttle control amount of the ship-based UAV model; at the same time, the scaled prototype changes according to the same rudder amount and throttle control amount Deflect the rudder surface and rotate the motor to keep the dynamics of the scaled prototype the same as the dynamics of the ship-based UAV model simulation operation;

Furthermore, the flight control computer and scaled prototype are real objects;

IV), the ground control station real-time monitors the position, attitude, speed, rudder surface deflection angle, motor throttle and motor speed state quantities of the carrier-based UAV model during flight.

Specifically: when the ship-based UAV model is to land on the deck of the ship model, the ship-based UAV model first autonomously follows the movement of the ship model and gradually approaches the landing point until it reaches above the landing point.

When the ship-based UAV model is at a long distance, the speed information and heading information of the ship model are transmitted to the flight control computer through the link, and are used as the input of the desired speed control and heading information of the ship-based UAV model. The UAV model gradually approaches the ship at the desired speed and heading; at close range, the flight control computer controls the UAV model to slow down and gradually approach from the side and rear of the ship model. The UAV model passes The navigation reduces the side offset and follows the movement direction of the ship model in a consistent manner.

The relative distance calculation formula between the carrier-based UAV model and the ship model is as follows:

in: d represents the relative distance between the deck of the ship model and the carrier-based UAV model; R is the radius of the earth; φ ₁ represents the latitude of the deck of the ship model, φ ₂ represents the latitude of the vertical take-off and landing ship-based UAV model; Δδ Represents the difference in longitude between the deck of the ship-based drone model and the ship model.

Calculate the relative speed of the two by combining relative distance and time, estimate the speed of the ship model, and then adjust the speed of the ship-based UAV model to be consistent with the speed of the ship model, keeping the ship-based UAV model always located on the ship Once the model is above the deck, start lowering the height.

During the descent process, when the preset target on the deck of the ship model reaches near the visual capture point of the ship-based UAV model, the ship-based UAV model introduces visual navigation to guide the UAV to land.

Visual navigation provides auxiliary guidance at a height of 5-10m near the landing of the ship-based UAV model to improve landing accuracy.

The advantages of the present invention are:

(1) The present invention is a semi-physical simulation system for UAV shipboard take-off and landing based on a physical domain model. By running the UAV model and the ship model simultaneously in X-Plane11 in a unified physical domain simulation environment, it can be more Really simulate the actual ship and surrounding sea conditions;

(2) The present invention is a semi-physical simulation system for UAV shipboard takeoff and landing based on the physical domain model. For different shipborne UAVs, only the corresponding UAV model needs to be established, and the shipboard simulation system can be carried out on this system. Carrier-based take-off and landing simulation currently supports semi-physical simulation of ship-based take-off and landing of fixed-wing, helicopter, quad-rotor and composite aircraft types;

(3) The present invention is a semi-physical simulation system for UAV shipboard take-off and landing based on the physical domain model. During the simulation process, the ship model can add wind fields, waves, and adjustment time according to the actual situation, so as to obtain a model that is more consistent with the actual situation. The movement of the ship is fed back to the flight control system;

(4) The present invention is a semi-physical simulation system for UAV shipboard take-off and landing based on the physical domain model. By designing a three-dimensional vision module, the three-dimensional vision software can be used to intuitively display the three-dimensional model of the ship-based UAV from The whole process from shipboard take-off to shipboard landing;

(5) The invention is a semi-physical simulation system for UAV shipboard take-off and landing based on the physical domain model, which can realize the UAV model to fully autonomously land the ship model, thereby verifying the flight control law and flight management logic;

(6) The present invention is a semi-physical simulation system for UAV carrier-based takeoff and landing based on the physical domain model. By designing and producing a scaled prototype of the carrier-based UAV, the flight process of the UAV can be more intuitively observed. Movements and changing trends of the rudder surface, motor, etc.;

(7) The present invention is a semi-physical simulation system for UAV carrier-based takeoff and landing based on a physical domain model, which can effectively save costs in the development process of carrier-based UAV flight control systems, improve efficiency, save time, and at the same time Carry out human-machine interaction, and for ship-borne manned aircraft, simulated flight training can also be carried out.

Description of the drawings

Figure 1 is a schematic diagram of the scaled prototype model used in the present invention;

Figure 2 is a schematic diagram of the semi-physical simulation system for shipboard take-off and landing of UAVs based on the physical domain model of the present invention;

Figure 3 is a flow chart of the semi-physical simulation system for shipboard take-off and landing of UAV according to the present invention;

Figure 4 is a schematic diagram of the UAV shipborne landing guidance scheme of the present invention;

Figure 5 is an interface diagram of the ship model control panel simulated by the present invention;

Figure 6 is a diagram showing the fully autonomous landing of the composite UAV aircraft carrier simulated by the present invention;

Figure 7 is a diagram showing the fully autonomous landing of an unmanned helicopter destroyer simulated by the present invention;

Figure 8 is a modeling display diagram of different types of UAVs according to the present invention;

Figure 9 is a diagram showing aircraft carrier modeling in the embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and examples.

Through research on the semi-physical simulation system of ship-based UAVs, the present invention designed a semi-physical simulation system for UAV ship-based takeoff and landing based on the physical domain model, and based on the mature S60N flight control computer and ground control software of the research group, A real-time communication mechanism for ship models, ship-borne UAV models and ship-aircraft simulations has been established. Through the visual software X-Plane 11 and the ground control software UAV_GCS50 running simultaneously on the same PC computer, the flight control computer can obtain the relative position, speed, heading and attitude of the ship-based UAV model and the ship model in real time. information, so as to control UAV flight more accurately and realize semi-physical simulation of UAV shipboard take-off and landing.

As shown in Figure 2, the semi-physical simulation system consists of four parts: S60N flight control computer, visual software, ground control software, scaled prototype and communication modules between each part. The scaled prototype The model is shown in Figure 1.

As shown in Figure 3, the specific construction process is as follows:

First, build a ship-based UAV model in Plane-Maker and Airfoil-Maker of X-Plane11, use AC3D software to build ship models such as aircraft carriers, frigates or destroyers, and then import them into X-Plane11 to solve them using the surface element method and leaf element method. The attitude and position of the ship-based UAV model and ship model are sent to the communication software IBC_Sim, and then the data is sent to the flight control computer using serial communication according to the protocol;

The flight control computer and scaled prototype are real objects, and the ship-based UAV model sends data such as the three-axis position, attitude angle, three-axis speed, and three-axis acceleration of the UAV model via UDP communication;

The ship model outputs the ship's course, position, speed, deck height and other information through the virtual serial port;

Specifically: Select Data Output/Dataref Read/Write in the settings menu bar of X-Plane 11, check the corresponding boat/heading_deg, boat/velocity_msc, boat/x_mtr, boat/y_mtr, boat/y_mtr, etc., and check Sent through the virtual serial port; the ship information is first sent from the Dataref Read/Write of X-Plane 11 to the communication software IBC_Sim through the virtual serial port, and then framed together with the inertial navigation data and sent to the 232-5 serial port of the flight control computer through the serial port. .

Then, the flight control computer calculates the control law to obtain the rudder and throttle control quantities of the carrier-based UAV model, and sends them to X-Plane11 and the scaled prototype at the same time;

The control law designs different control channels according to different models. Each control channel is divided into an inner loop and an outer loop. The inner loop completes attitude control; the outer loop completes position/speed control; both the inner and outer loops use cascade PID controllers.

The structure of the PID controller according to the present invention is as follows:

u(k)＝K(u _p (k)+u _i (k)+u _d (k))

Among them, u _p (k) is the proportional term of the PID controller, k _p1 is the gain of the first proportional link, e (k) is the error term, and P _div is the error threshold of the proportional term. According to the relationship between the error term and the error threshold Perform segmented calculations; k _p2 is the gain of the second proportional link;

u _i (k) is the integral term of the PID controller, k _i is the gain of the integral link, T is the time constant of the differential term, ε is the error threshold of the integral term, and the segmented calculation is performed based on the relationship between the error term and the error threshold;

u _d (k) is the differential term of the PID controller, k _d is the gain of the differential link, and y(k) is the current value of the differential term;

u(k) is the control quantity of the PID controller, and K is the total coefficient.

Specifically, different carrier-based UAV models correspond to different control laws:

For quad-rotor models, the control law design includes longitudinal outer ring height control-inner ring pitch angle control; heading outer ring heading distance/speed control-inner ring course angle control; lateral outer ring lateral distance/speed control-inner ring roll angle control control;

For fixed-wing aircraft, the control law design includes longitudinal outer ring height-inner ring pitch angle control; heading horizontal position/heading control; lateral outer ring sideslip distance-inner ring roll angle control; and airspeed control;

For composite aircraft, corresponding to different flight modes, the control law is a combination of quad-rotor aircraft and fixed-wing aircraft;

For helicopter models, the control law design includes longitudinal outer ring height control-inner ring pitch angle control; heading outer ring heading distance/speed control-inner ring course angle control; lateral outer ring lateral distance/speed control-inner ring roll angle control ;

Then, the visual software X-Plane11 realizes the visual display of the ship-based UAV model's full-process simulation of ship-based take-off, mode switching, hovering and ship-based landing flight. At the same time, the scaled prototype will adjust the control surface as the control amount changes. The deflection and the rotation of the motor keep the dynamics of the scaled prototype the same as the dynamics of the ship-based UAV model simulated and run on the PC;

Finally, the ground control station monitors the carrier-based UAV model's position, attitude, speed, rudder deflection angle, motor throttle and motor speed status in real time during flight, and can send corresponding instructions as needed. After the entire physical-in-the-loop simulation system is running, the ship-based takeoff, sea flight and ship-based landing of the UAV model can be realized under the real-time control of the flight control computer. .

When the ship-based UAV semi-physical simulation system is running, the speed and heading of the ship are controlled through the control panel, and the landing process of the UAV model is guided, as shown in Figures 4 and 5, specifically:

When the ship-based UAV model is about to land on the deck of the ship model, the UAV model first autonomously follows the movement of the ship model and gradually approaches the landing point until the UAV reaches the top of the landing point; The degree of freedom motion information is used to estimate the landing timing and perform landing when the ship's attitude is level, ensuring that the ship's attitude is level when the drone touches the ground, and the landing will not fail due to the ship's attitude being too large.

When the UAV model is at a long distance, the speed information and heading information of the ship model are transmitted to the flight control computer through the link, which is used as input to control the expected speed of the UAV model and the UAV model heading information. The UAV model gradually approaches the ship at the desired speed and heading. When at close range, the flight control computer controls the UAV model to slow down and gradually approach from the side and rear of the ship. The UAV reduces the side offset through navigation and is consistent with the ship model. Keep the direction of movement consistent and follow.

The relative distance calculation formula between the drone model and the ship model is as follows:

in: d represents the relative distance between the deck of the ship model and the carrier-based UAV model; R is the radius of the earth; φ ₁ represents the latitude of the deck of the ship model, φ ₂ represents the latitude of the vertical take-off and landing ship-based UAV model; Δδ Represents the difference in longitude between the deck of the ship-based drone model and the ship model.

As shown in Figure 6 and Figure 7, the relative speed of the two is calculated by combining the relative distance and time, and the speed of the ship model is estimated. Then the speed of the UAV model is adjusted to be consistent with the speed of the ship to keep the UAV model always Once above the ship's deck, begin to lower the altitude.

During the descent process, when the preset target on the ship deck reaches near the visual capture point of the UAV model, the ship-based UAV model introduces visual navigation to guide the UAV to land. The semi-physical simulation of visual navigation is realized through the camera mounted on the UAV model. In X-Plane, it can be realized through the perspective plug-in x-camera, so as to obtain the precise position and attitude information of the UAV model relative to the ship model. Guide the drone model to land.

Visual navigation only provides auxiliary guidance when the UAV model lands near the ground (5-10m) to improve landing accuracy.

The specific process of visual navigation is as follows: When the ship's target reaches near the visual capture point of the UAV model, an image guidance system is introduced to collect images in real time, and image processing technology is used to extract and calculate features of the collected images to calculate the unmanned aerial vehicle. The attitude information of the aircraft relative to the ship model is then output to the flight control computer. The flight control makes the drone land on the ship model with higher accuracy based on the position and attitude information of the visual navigation system.

The collected images are target images arranged in advance on the ship model. When extracting features from the images, opencv's ArUco code can be used. The specific encoding method is Hamming code, which has error detection and correction capabilities and strong anti-interference ability. . The marker is identified by identifying the information at the four corners of ArUco. The QR code in the middle of the marker contains the marker information.

In this embodiment, different carrier-based drone models and ship models are created in Plane-Maker, as shown in Figures 8 and 9. After being imported into the visual software X-Plane11, the model position and attitude analysis can be completed. Calculate and send this information to the flight control computer through communication software. After the control law is solved, the control quantity is output to the model and scaled prototype, thereby realizing the flight path planning and flight of the ship-based UAV model by the flight control computer. attitude control;

The ground control software is used to transmit control instructions; the scaled prototype is used to synchronously display the movements of the rudder surface and motor during the movement of the UAV model; the visual software is used to display the entire flight process of the three-dimensional carrier-based UAV model. Including takeoff, following, landing, mode switching, etc.

Claims (5)

1. A semi-physical simulation system for UAV shipboard takeoff and landing based on a physical domain model, which is characterized by: First, build the carrier-based UAV model and ship model on the X-Plane11 platform, calculate the attitude and position of the ship-based UAV and ship through the surface element method and leaf element method, and send them to the flight control computer; the flight control computer After solving the control law, the rudder control amount and throttle control amount of the carrier-based UAV model are obtained, and are sent to the X-Plane11 platform and scaled prototype at the same time; Then, the X-Plane11 platform simulates the entire process of takeoff, mode switching, circling and landing according to the rudder amount and throttle control amount of the ship-based UAV model; at the same time, the scaled prototype simulates the same rudder amount and throttle control amount changes. The deflection of the rudder surface and the rotation of the motor keep the dynamics of the scaled prototype the same as the dynamics of the ship-based UAV model simulation operation; Finally, the ground control station monitors the position, attitude, speed, rudder deflection angle, motor throttle and motor speed status of the ship-based UAV model in real time during flight; The described control law designs different control channels according to different models. Each control channel is divided into an inner loop and an outer loop. The inner loop completes attitude control; the outer loop completes position/speed control; both the inner and outer loops use cascade PID controllers; The structure of the PID controller is as follows: u(k)＝K(u _p (k)+u _i (k)+u _d (k)) Among them, u _p (k) is the proportional term of the PID controller, k _p1 is the gain of the first proportional link, e(k) is the error term, P _div is the error threshold of the proportional term, and k _p2 is the gain of the second proportional link. ; u _i (k) is the integral term of the PID controller, k _i is the gain of the integral link, T is the time constant of the differential term, and ε is the error threshold of the integral term; u _d (k) is the differential term of the PID controller, k _d is the gain of the differential link, and y(k) is the current value of the differential term; u(k) is the control quantity of the PID controller, and K is the total coefficient; The different carrier-based UAV models correspond to different control laws, specifically: For the quad-rotor model, the control law design includes longitudinal outer ring height control-inner ring pitch angle control; course outer ring heading distance/speed control-inner ring course angle control; transverse outer ring lateral distance/speed control-inner ring roll angle control. control; For fixed-wing aircraft, the control law design includes longitudinal outer ring height-inner ring pitch angle control; heading horizontal position/heading control; lateral outer ring sideslip distance-inner ring roll angle control; and airspeed control; For composite aircraft, corresponding to different flight modes, the control law is a combination of quad-rotor aircraft and fixed-wing aircraft; For helicopter models, the control law design includes longitudinal outer ring height control-inner ring pitch angle control; heading outer ring heading distance/speed control-inner ring course angle control; lateral outer ring lateral distance/speed control-inner ring roll angle control . 2. A semi-physical simulation system for UAV ship-based takeoff and landing based on a physical domain model as claimed in claim 1, characterized in that the data sent by the ship-based UAV model includes: the data of the UAV. Three-axis position, attitude angle, three-axis velocity and three-axis acceleration; The data output by the ship model includes: the ship's course, position, speed and deck height. 3. A semi-physical simulation system for UAV carrier-based takeoff and landing based on a physical domain model as claimed in claim 1, characterized in that the flight control computer and the scaled prototype are physical objects. 4. A semi-physical simulation system for UAV ship-based takeoff and landing based on a physical domain model as claimed in claim 1, characterized in that the ship-based UAV model is to land on the deck of the ship model. At long distances, the ship-based UAV model first autonomously follows the movement of the ship model. The speed information and heading information of the ship model are transmitted to the flight control computer through the link and serve as the expected speed of the ship-based UAV model. With the input of control and heading information, the ship-based UAV model gradually approaches the ship at the desired speed and heading; The relative distance calculation formula between the carrier-based UAV model and the ship model is as follows: in: d represents the relative distance between the deck of the ship model and the carrier-based UAV model; R is the radius of the earth; φ ₁ represents the latitude of the deck of the ship model, φ ₂ represents the latitude of the vertical take-off and landing ship-based UAV model; Δδ Represents the difference in longitude between the deck of the ship-based drone model and the ship model; Calculate the relative speed of the two by combining relative distance and time to estimate the speed of the ship model. When at close range, the flight control computer controls the ship-based UAV model to decelerate and adjust the speed of the ship-based UAV model to the ship model. The speed is consistent and gradually approaches from the side and rear of the ship model. The ship-based UAV model reduces the side offset through navigation, follows the ship model in the same direction of movement, and lowers its altitude. 5. A semi-physical simulation system for UAV shipboard takeoff and landing based on a physical domain model as claimed in claim 4, characterized in that during the descent process, the target preset on the ship model deck reaches the shipboard When the drone model is near the visual capture point, the ship-based drone model introduces visual navigation to guide the drone to land; Visual navigation provides auxiliary guidance at a height of 5-10m near the landing of the ship-based UAV model to improve landing accuracy.