Flight control system of aircraft for transportation

Abstract

The invention discloses a flight control system of an aircraft for transportation. The flight control system comprises a position subsystem, an attitude subsystem, an attitude controller, a position controller and an attitude resolving module, a position controller obtains a vertical speed control quantity and inputs the vertical speed control quantity to a position subsystem, and a required expected attitude Euler angle is solved at the same time; selecting a control mode according to the preliminarily calculated expected attitude Euler angle, and recalculating the attitude Euler angle; an attitude Euler angle control quantity is obtained through an attitude controller of the attitude subsystem, and the attitude Euler angle control quantity is output to the attitude subsystem; according to the method, the unknown cargo swing disturbance variable can be added into the mathematical model of the four-rotor unmanned aerial vehicle, and the attitude of the four-rotor unmanned aerial vehicle is controlled through the PID controller; and the transportation unmanned aerial vehicle is introduced into the cruise machine to replace a subsequent transportation task through a unit time processing time sequence in an emergency state, so that the transportation efficiency of the transportation unmanned aerial vehicle is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of transport unmanned aerial vehicle control, and in particular to a flight control system of an aircraft for transportation. Background Art

[0002] At present, with the continuous advancement of technology, unmanned aerial vehicles have been widely used in all walks of life. For example, unmanned aerial vehicles are used to transport goods in mountainous areas; transportation is usually between mountains, and between mountains and the bottom of mountains; this type of transportation is affected by the terrain, and the cost of building roads is high. Considering all factors, unmanned aerial vehicles are usually used for transportation, and large quad-rotor unmanned aerial vehicles are generally used for transportation. During the transportation flight of existing unmanned aerial vehicles, sometimes the wind blows the goods they carry, causing interference with the swing of the goods, which in turn affects the Euler angle of the flight attitude. Summary of the invention

[0003] To this end, the present invention provides a flight control system for a transportation aircraft to solve the above-mentioned problems in the prior art.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] According to a first aspect of the present invention, a flight control system for a transportation aircraft,

[0006] A flight control system for a transportation aircraft, comprising a position subsystem, an attitude subsystem, an attitude controller, a position controller and an attitude solving module; the position subsystem comprises a position controller, the position controller obtains a vertical speed control amount and inputs it into the position subsystem, and simultaneously solves the required desired attitude Euler angle; the attitude Euler angle comprises a pitch angle θ, a roll angle and yaw angle ψ; select the control mode according to the initially calculated desired attitude Euler angle, and recalculate the attitude Euler angle; obtain the attitude Euler angle control quantity, i.e., the pitch angle control quantity, roll angle control quantity and yaw angle control quantity, through the attitude controller of the attitude subsystem, and output the attitude Euler angle control quantity to the attitude subsystem; set the virtual control quantity u of the position controller x 、u y 、u z The calculation formula is:

[0007]

[0008] According to the above formula, the calculation formula of the vertical speed control quantity U1 is:

[0009]

[0010] According to the calculation formula of the virtual control quantity of the position controller and the mathematical model of the quadrotor aircraft, the position subsystem model can be simplified as follows:

[0011]

[0012] The position error is defined using a sliding mode controller:

[0013]

[0014] Where: the lift generated by the four propellers is F1-F4 respectively, the UAV has four control inputs: vertical speed control quantity U1, roll angle control quantity U2, pitch angle control quantity U3, yaw angle control quantity U4; x, y, z are the position coordinates of the UAV in the inertial coordinate system; f x 、f y 、f z is the unknown swing disturbance of the cargo; m is the mass of the aircraft; g is the acceleration of gravity; e x 、e y 、e z is the coordinate of the position error; x d 、x y 、x z is the coordinate of the corresponding virtual position of the drone in the inertial coordinate system.

[0015] Further: The relationship between the lift and the control amount is:

[0016] ;

[0018] Where l is the distance between the center of each propeller and the center of mass of the drone O b distance;

[0019] From the Newton-Euler equation, the mathematical model of the quadrotor aircraft can be obtained as:

[0020]

[0021] Where: x, y, z are the position coordinates of the drone in the inertial coordinate system; f x 、f y 、f z It is the unknown swing interference of the cargo; x ,I y ,I z is the X coordinate system around the body b , Y b , Z b The moment of inertia of the axis; m is the mass of the aircraft; g is the acceleration due to gravity.

[0022] Furthermore: a PID controller is used to control the attitude of the quadrotor drone, and the difference between the expected attitude Euler angle and the calculated value of the current attitude Euler angle is used as the input of the PID controller; and a PWM signal is output to each motor to drive the motor; the outputs of the three PID controllers are superimposed on the electronic speed regulators at different positions, and the speed of the driving motor changes, so that the drone can complete the movement in the three-dimensional space.

[0023] Furthermore: in order to ensure the transportation efficiency of multiple drone transports, a cruise aircraft is set up outside the normal drone formation, and the drones being transported are assumed to be mission aircraft; when a mission aircraft encounters an emergency, a cruise aircraft is assigned to the mission aircraft, and the cruise aircraft performs circle cruising in the middle area of ​​the transportation location; when multiple mission aircraft encounter multiple emergencies, the ground station uses a first-come-first-served scheduling mechanism to assign a cruise aircraft to the mission aircraft where the incident occurred earlier; when emergencies occur at the same time, cruise aircraft are assigned to mission aircraft with smaller emergency mission aircraft numbers first; the emergency mission aircraft number is determined by the distance of the outbound drone closest to the location where the goods are to be transported.

[0024] Further: There are three objects in the UAV transportation network, namely the mission aircraft, the ground station and the cruise aircraft. Then, in each unit time, each UAV first detects its own status parameters, judges whether it is urgent or non-urgent on the UAV body, and sends an emergency or non-urgent signal to the ground station through the network. The ground station updates the status of each UAV and allocates a cruise aircraft to the mission aircraft based on a first-come-first-served mechanism; then the command information for changing the Locked bit is sent to the cruise aircraft, and finally the cruise aircraft makes an adjusted flight time Δt according to the flight control algorithm.

[0025] Furthermore: the Locked position is a flag that indicates whether the mission machine and the cruise machine can be paired with each other; when the ferry machine is assigned to the emergency mission machine, the Locked position of the cruise machine and the mission machine is real; when the motor status parameter in the cruise machine reaches the warning value, the cruise machine and the mission machine originally paired with it will be unlocked.

[0026] The present invention has the following advantages: the present invention can add unknown swing interference of cargo into the mathematical model of the quad-rotor UAV, and control the attitude of the quad-rotor UAV through a PID controller; and introduces the concept of a cruise aircraft, so that the transport UAV can introduce a cruise aircraft to replace subsequent transport tasks through a unit time processing sequence in an emergency state, thereby further improving the transport efficiency of the transport UAV. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the quadrotor aircraft in the present invention.

[0028] Figure 2The present invention is a schematic structural diagram of a flight control system of an aircraft for transportation.

[0029] Figure 3 It is a schematic diagram of the attitude PID control process in the flight control system of the present invention.

[0030] Figure 4 It is a timing diagram of unit time processing under emergency state in the present invention. DETAILED DESCRIPTION

[0031] The following is an explanation of the implementation of the present invention by specific specific examples. People familiar with this technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. It should be understood that these embodiments are only to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Technical engineers in this field can make some non-essential improvements and adjustments to the present invention based on the contents of the above invention; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] like Figure 1-4 As shown, a flight control system for a transportation aircraft in an embodiment of the first aspect of the present invention includes a position subsystem, an attitude subsystem, an attitude controller, a position controller and an attitude solving module; the position subsystem includes a position controller, the position controller obtains a vertical speed control amount and inputs it into the position subsystem, and simultaneously solves the required desired attitude Euler angle; the attitude Euler angle includes a pitch angle θ, a roll angle and yaw angle ψ; select the control mode according to the initially solved desired attitude Euler angle, and recalculate the attitude Euler angle; obtain the attitude Euler angle control quantity, i.e. the pitch angle control quantity, roll angle control quantity and yaw angle control quantity, through the attitude controller of the attitude subsystem, and output the attitude Euler angle control quantity to the attitude subsystem.

[0034] The structure of a quad-rotor drone is as follows: Figure 1 As shown, first establish the relational coordinate system e and the drone coordinate system b; θ, ψ represents the pitch angle, roll angle and yaw angle of the drone respectively; R1-R4 are the four propellers of the aircraft, and the directions of any two adjacent propellers are opposite; the lifts generated by the four propellers are F1-F4 respectively, and the drone has four control inputs: vertical speed control quantity U1, roll angle control quantity U2, pitch angle control quantity U3, and yaw angle control quantity U4; the relationship between the lift and the control quantity is:

[0035]

[0036] Where l is the distance between the center of each propeller and the center of mass of the drone O b distance;

[0037] From the Newton-Euler equation, the mathematical model of the quadrotor aircraft can be obtained as:

[0038]

[0039] Where: x, y, z are the position coordinates of the drone in the inertial coordinate system; f x 、f y 、f z Unknown swing interference of cargo; I x ,I y ,I z is the X coordinate system around the body b , Y b , Z b The moment of inertia of the axis; m is the mass of the aircraft; g is the acceleration due to gravity.

[0040] Assume that the virtual control quantity u of the position controller x 、u y 、u z The calculation formula is:

[0041]

[0042] According to the above formula, the calculation formula of the vertical speed control quantity U1 is:

[0043]

[0044] According to the calculation formula of the virtual control quantity of the position controller and the mathematical model of the quadrotor aircraft, the position subsystem model can be simplified as follows:

[0045]

[0046] The position error is defined using a sliding mode controller:

[0047]

[0048] f x 、f y 、f z For unknown swing disturbance of goods, RBF neural network is introduced to predict the unknown swing disturbance and obtain the predicted value; the predicted value is brought into the non-singular terminal sliding membrane controller function, and the virtual control amount of the position controller can be obtained.

[0049] In the embodiment of the present invention, Figure 3As shown in the figure, a PID controller is used to control the attitude of a quadrotor drone, and the difference between the expected attitude Euler angle and the calculated value of the current attitude Euler angle is used as the input of the PID controller; and a PWM signal is output to each motor to drive the motor; the outputs of the three PID controllers are superimposed on the electronic speed regulators at different positions, and the speed of the driving motor changes, so that the drone can complete the movement in the three-dimensional space.

[0050] In the above embodiment, it should be noted that the adopted PID controller can advance the phase of the entire system through differential parameters, and can also eliminate the jitter of the drone during flight, thereby ensuring the stability of the entire drone system.

[0051] In addition, since most existing drone transportation is carried out by multiple drone formations, in an embodiment of the present invention, in order to ensure the transportation efficiency of multiple drone transportations, a cruise aircraft is set outside the normal drone formation, and the drone being transported is assumed to be a mission aircraft.

[0052] When an emergency occurs on a mission aircraft, a cruise aircraft will be assigned to the mission aircraft, and the cruise aircraft will circle around the middle area of ​​the transportation location. When multiple emergencies occur on multiple mission aircraft, the ground station uses a first-come-first-served scheduling mechanism to assign a cruise aircraft to the mission aircraft where the incident occurred earlier. When emergencies occur at the same time, cruise aircraft will be assigned to mission aircraft with smaller emergency mission aircraft numbers. The emergency mission aircraft number is determined by the distance of the outbound drone closest to the location where the goods are to be transported.

[0053] Further: Figure 4 As shown in the figure, assuming that there are three objects in the UAV transportation network, namely the mission aircraft, the ground station and the cruise aircraft, then in each unit time, each UAV first detects its own state parameters, judges whether it is urgent or non-urgent on its own (each UAV), and sends an emergency or non-urgent signal to the ground station through the network. The ground station updates the status of each UAV and allocates a cruise aircraft to the mission aircraft according to the first-come-first-served mechanism; then the command information of changing the Locked bit is sent to the cruise aircraft, and finally the cruise aircraft makes an adjusted flight time Δt according to the flight control algorithm.

[0054] In this embodiment, the Locked bit is a flag bit that indicates whether the mission aircraft and the cruise aircraft can be paired with each other; when the ferry is assigned to the emergency mission aircraft, the Locked bits of the cruise aircraft and the mission aircraft are true; when the motor status parameters in the cruise aircraft (which can also be UAV status parameters, including endurance time, etc.) reach the warning value, the cruise aircraft and the mission aircraft originally paired with it will be unlocked.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A flight control system for a transportation aircraft, characterized in that: It includes a position subsystem, an attitude subsystem, an attitude controller, a position controller and an attitude solving module; the position subsystem includes a position controller, which obtains the vertical speed control amount and inputs it into the position subsystem, and simultaneously solves the required desired attitude Euler angle; the attitude Euler angle includes the pitch angle θ, the roll angle and yaw angle ψ; select the control mode according to the initially calculated desired attitude Euler angle, and recalculate the attitude Euler angle; obtain the attitude Euler angle control quantity, i.e., the pitch angle control quantity, roll angle control quantity and yaw angle control quantity, through the attitude controller of the attitude subsystem, and output the attitude Euler angle control quantity to the attitude subsystem; set the virtual control quantity u of the position controller x 、u y 、u z The calculation formula is: According to the above formula, the calculation formula of the vertical speed control quantity U1 is: According to the calculation formula of the virtual control quantity of the position controller and the mathematical model of the quadrotor aircraft, the position subsystem model can be simplified as follows: The position error is defined using a sliding mode controller: Where: the lift generated by the four propellers is F1-F4 respectively, the UAV has four control inputs: vertical speed control quantity U1, roll angle control quantity U2, pitch angle control quantity U3, yaw angle control quantity U4; x, y, z are the position coordinates of the UAV in the inertial coordinate system; f x 、f y 、f z is the unknown swing disturbance of the cargo; m is the mass of the aircraft; g is the acceleration of gravity; e x 、e y 、e z is the coordinate of the position error; x d 、x y 、x z is the coordinate of the corresponding virtual position of the drone in the inertial coordinate system.

2. The flight control system of a transportation aircraft according to claim 1, characterized in that: The relationship between the lift and the control amount is: Where l is the distance between the center of each propeller and the center of mass of the drone O b distance; From the Newton-Euler equation, the mathematical model of the quadrotor aircraft can be obtained as: Where: x, y, z are the position coordinates of the drone in the inertial coordinate system; f x 、f y 、f z Unknown swing interference of cargo; I x ,I y ,I z is the X coordinate system around the body b , Y b , Z b The moment of inertia of the axis; m is the mass of the aircraft; g is the acceleration due to gravity.

3. The flight control system of a transportation aircraft according to claim 1, characterized in that: A PID controller is used to control the attitude of a quadrotor UAV. The difference between the expected attitude Euler angle and the calculated value of the current attitude Euler angle is used as the input of the PID controller. A PWM signal is output to each motor to drive the motor. The outputs of the three PID controllers are superimposed on the electronic speed regulators at different positions, and the speed of the driving motor changes, so that the UAV can complete the movement in the three-dimensional space.

4. A flight control system for a transportation aircraft according to any one of claims 1 to 3, characterized in that: In order to ensure the transportation efficiency of multiple drone transports, cruise aircraft are set up outside the normal drone formation, and the drones being transported are assumed to be mission aircraft; when a mission aircraft encounters an emergency, a cruise aircraft is assigned to the mission aircraft, and the cruise aircraft performs circle cruising in the middle area of ​​the transportation location; when multiple mission aircraft encounter multiple emergencies, the ground station's first-come-first-served scheduling mechanism assigns a cruise aircraft to the mission aircraft where the incident occurred earlier; when emergencies occur at the same time, cruise aircraft are assigned to mission aircraft with smaller emergency mission aircraft numbers first; the emergency mission aircraft number is determined by the distance of the outbound drone closest to the location where the goods are to be transported.

5. The flight control system of a transportation aircraft according to claim 4, characterized in that: There are three objects in the UAV transportation network, namely the mission aircraft, the ground station and the cruise aircraft. Then, in each unit time, each UAV first detects its own status parameters, judges whether it is emergency or non-emergency on the UAV body, and sends an emergency or non-emergency signal to the ground station through the network. The ground station updates the status of each UAV and allocates a cruise aircraft to the mission aircraft based on a first-come-first-served mechanism; then the command information to change the Locked bit is sent to the cruise aircraft, and finally the cruise aircraft makes an adjusted flight time Δt according to the flight control algorithm.

6. The flight control system of a transportation aircraft according to claim 4, characterized in that: The Locked position is a flag that indicates whether the mission machine and the cruise machine can be paired with each other; when the ferry is assigned to the emergency mission machine, the Locked position of the cruise machine and the mission machine is real; when the motor status parameter in the cruise machine reaches the warning value, the cruise machine and the mission machine originally paired with it will be unlocked.

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