CN114047774B - Verification method for four-rotor unmanned aerial vehicle operation simulation in low-altitude layered airspace - Google Patents
Verification method for four-rotor unmanned aerial vehicle operation simulation in low-altitude layered airspace Download PDFInfo
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Abstract
The invention provides a verification method for four-rotor unmanned aerial vehicle operation simulation in a low-altitude layered airspace, which comprises the following steps: s1, determining a coordinate system required by simulation and establishing a nonlinear mathematical model of the four-rotor unmanned aerial vehicle; s2, building a four-rotor track, a gesture and an angular velocity flight control law based on a nonlinear dynamic inverse method; s3, calculating the rotating speed of the propeller according to the rotor wing tension obtained by solving the control law; s4, designing a low-altitude layered airspace below 120 meters according to the flying heading of the unmanned aerial vehicle; s5, designing a flight profile of the unmanned aerial vehicle according to the layered airspace; and S6, performing simulation verification according to the four-rotor unmanned aerial vehicle closed-loop motion model, the layered airspace and the flight profile. The method simulates the isolated operation of the four-rotor unmanned aerial vehicle in the low-altitude layered airspace to the maximum extent, and has universal applicability.
Description
Technical Field
The invention relates to the field of unmanned aerial vehicle operation simulation, in particular to a verification method for four-rotor unmanned aerial vehicle operation simulation in a low-altitude layered airspace.
Background
The unmanned aerial vehicle is widely applied to activities such as aerial photography, geographical mapping, image acquisition, air inspection, agriculture and forestry spraying, communication relay and the like at present, particularly urban air traffic which is rapidly developed in recent years is proposed, and the civil unmanned aerial vehicle is fused into a low-altitude space of a city to provide services such as logistics freight and manned traffic for urban residents. However, as the operation amount of the unmanned aerial vehicle increases, the operation risk of the unmanned aerial vehicle at a low altitude below 120 meters is increased, and the problem that how to avoid the air collision of the unmanned aerial vehicle, ensure the operation safety of the unmanned aerial vehicle and improve the airspace capacity is worth researching in the development process of the operation management technology of the civil unmanned aerial vehicle.
The Chinese patent with the application number of CN112947515A discloses an aircraft urban air traffic energy consumption control method based on an optimized cruising altitude layer, and the proposed cruising airspace layering method has a certain reference significance for relieving air congestion and guaranteeing unmanned aerial vehicle operation safety. At present, the operation safety of the unmanned aerial vehicle is researched, and the principle of corresponding actual flight verification is developed on the basis of a large number of flight simulations, so that the simulation verification method of the unmanned aerial vehicle in low-altitude operation is researched.
Disclosure of Invention
The invention aims to: in order to know the requirements of unmanned aerial vehicle low-altitude operation simulation verification, the invention builds a closed-loop model with track control capability according to the motion characteristics of the four-rotor unmanned aerial vehicle, performs nonlinear mathematical modeling and corresponding control law design, further performs layered design on a low-altitude airspace, and controls unmanned aerial vehicles with different heading to fly at corresponding flying heights according to flight profiles, thereby performing simulation verification.
The invention is realized by the following technical scheme:
a simulation verification method for operation of a quadrotor unmanned aerial vehicle in a low-altitude layered airspace comprises the following steps:
step 1, determining a coordinate system required by simulation and establishing a nonlinear mathematical model of the four-rotor unmanned aerial vehicle;
step 2, building a four-rotor track, a gesture and an angular velocity flight control law based on a nonlinear dynamic inverse method;
step 3, distributing the rotating speed of the propeller according to the rotor wing tension obtained by solving the control law;
step 4, layering the empty domain;
step 5, designing a flight profile of the unmanned aerial vehicle according to the layered airspace, wherein the flight profile comprises a vertical take-off stage, a cruising stage and a vertical landing stage of the unmanned aerial vehicle;
and 6, carrying out simulation verification.
In step 1, the coordinate system required by the simulation is determined as follows:
body coordinate system: origin of coordinate system O b Is arranged at the gravity center of the unmanned aerial vehicle, o b x b The shaft points to the direction of the machine head in the symmetry plane of the four-rotor unmanned aerial vehicle, o b z b The axis is in the symmetry plane of the four rotors and is perpendicular to o b x b Axially downwards and then according to the right hand rule o is determined b y b A shaft;
ground coordinate system: origin O of coordinate axis e Is arranged at the gravity center of the unmanned aerial vehicle, o e x e The axis points to north o e z e The axis plumb is downward and then o is determined according to the right hand rule e y e The axis is directed to the east.
In step 1, the building of the nonlinear mathematical model of the quadrotor unmanned aerial vehicle includes building the following equation:
four rotor tension equations:
in U i And omega i Respectively representing the rotor tension and the rotation speed of the ith rotor, i=1, 2,3,4, l represents a multi-rotor tension arm, C t And C q The dimensionless tension coefficient and the torque coefficient of the propeller are respectively represented, and omega is a rotating speed coefficient related to the torque generated by the propeller;
four rotor dynamics equations:
wherein m represents the mass of the quadrotor unmanned aerial vehicle and g represents the weight plus gravitySpeed, X, Y, Z, represents the unmanned aerial vehicle coordinate position,representing the derivative of coordinates with respect to time, i.e. unmanned ground speed,/->Representing the second derivative of coordinates with respect to time, namely the triaxial acceleration of the unmanned aerial vehicle, p, q and r respectively represent the roll, pitch and yaw angular velocities of the unmanned aerial vehicle, phi, theta and psi respectively represent the roll angle, pitch angle and yaw angle of the unmanned aerial vehicle, I XX 、I YY And I ZZ Respectively represent the triaxial moment of inertia of the unmanned aerial vehicle, I R Representing the moment of inertia of the rotor shaft.
The step 2 comprises the following steps:
for a multiple-input multiple-output nonlinear system, the following equation is established:
order theThen:
u＝G -1 (x)(-F(x)+K c (x c -x))
wherein x represents a state quantity vector, y represents an output vector, u represents a control quantity vector, and x c Representing a target control quantity matrix, K c A matrix of gain coefficients is represented and,the rate of change of the state quantity with respect to time is represented by F (x), the state matrix of the system is represented by G (x), the control matrix of the system is represented by H (x), and the functional relationship between x and y is represented by H (x).
In step 2, the following input/output variable matrix is used:
the rotor rotation speed distribution module inputs the variables: four rotor tension components;
rotor speed distribution module output variable: four rotor speeds;
angular velocity loop input variable: a pitch angle speed, a roll angle speed, and a yaw angle speed command;
angular velocity loop output variable: the pulling force of the three rotors;
attitude angle ring input variable: a three axis acceleration command;
attitude angle ring output variable: roll angle, pitch angle, yaw angle.
The step 3 comprises the following steps: the input instruction of the track loop is a target track, and the output instruction is a target roll angle, a target pitch angle and a tension component U 1 The method comprises the steps of carrying out a first treatment on the surface of the Firstly, calculating the target line speed according to the position error, wherein the calculation formula is as follows:
in the formula, the vector P= [ X, Y, Z] T Representing the current position coordinates of four rotors, P c The input coordinate instruction is represented as such,a derivative instruction of the four-rotor unmanned aerial vehicle coordinate to time is obtained through calculation; omega p Gain matrix, ω, representing position error x ，ω x And omega z The three direction coordinate instruction gains of X, Y and Z are respectively expressed;
the linear acceleration is calculated by the following equation:
in the vectorRepresenting the triaxial acceleration;
according to the dynamics equation of the four-rotor unmanned aerial vehicle, the tension U is obtained 1 Relationship with linear acceleration:
wherein g represents a gravitational acceleration; the target roll angle phi is calculated from the following equation c ：
Wherein psi is c Representing the input target course angle, and obtaining the target pitch angle theta c ：
The attitude angle loop inputs instructions as a target rolling angle, a pitch angle and a yaw angle, and outputs instructions as a target triaxial angular speed, and the attitude angle loop is obtained according to flight mechanics knowledge:
sorting into a nonlinear system form:
wherein F is 1 And G 1 Representing the state and control matrix, respectively, the target three-axis angular velocity is calculated from the following equation:
wherein p is c 、q c 、r c Respectively representing the calculated roll angle, pitch angle and yaw angle instructions omega attitude Bandwidth matrix, ω, representing attitude angle error φ ，ω θ And omega ψ Gains respectively representing unmanned aerial vehicle roll angle, pitch angle and yaw angle instructions; the target angular velocity instruction obtained by the loop directly enters the next loop;
the input instruction of the angular velocity loop is a target angular velocity instruction transmitted by the previous loop, and the output instruction is a tension component U 2 、U 3 And U 4 The method comprises the steps of carrying out a first treatment on the surface of the According to the four-rotor unmanned aerial vehicle kinematics equation, the four-rotor unmanned aerial vehicle is arranged as follows:
in the method, in the process of the invention,the derivatives of the roll angle speed, the pitch angle speed and the yaw angle speed with respect to time, namely the triaxial angular acceleration, are respectively expressed, and the following results are obtained:
wherein F is 2 And G 2 Representing the state and control matrix, respectively, the target tension is calculated from the following equation:
in the middle of force A bandwidth matrix representing angular velocity errors; target tension finger obtained by the loopU obtained by the ring of the command and position 1 The command enters a control law endmost rotor rotation speed distribution module;
the rotor rotation speed distribution module inputs a target tension which is obtained by a control law, outputs a multi-rotor rotation speed, and obtains according to a four-rotor tension equation:
thereby obtaining the rotation speeds of the four rotors.
Step 4 comprises: dividing airspace of more than 40 meters and less than 120 meters based on flight heading, and dividing four altitude layers in total by taking every 90-degree heading as a unit.
The step 5 comprises the following steps: the unmanned aerial vehicle takes off from the ground, vertically rises to a designated height layer, cruises at a fixed height in the height layer, and vertically falls to the ground after reaching the position right above the destination.
The step 6 comprises the following steps: inputting a height instruction into a four-rotor unmanned aerial vehicle nonlinear mathematical model to perform take-off simulation; after reaching the cruising altitude, inputting a flight path instruction into a four-rotor unmanned aerial vehicle nonlinear mathematical model to carry out cruising stage simulation; after the landing command reaches the upper air of the destination, the landing command is input into a nonlinear mathematical model of the four-rotor unmanned aerial vehicle, and landing stage simulation is developed.
In summary, the core idea of the invention is to select the cruising altitude according to the flying heading based on the four-rotor unmanned plane closed-loop mathematical model with track keeping capability, and complete the closed-loop simulation of the running process by externally inputting the track instruction and altitude instruction. As unmanned aerial vehicles with different heading are operated on different height layers and have a longitudinal interval which is wide enough, the flight safety is ensured.
Compared with the prior art, the invention has the following beneficial technical effects:
aiming at the operation simulation verification method of the quadrotor unmanned aerial vehicle in the low-altitude layered space domain, the invention adopts a nonlinear dynamic inverse control method, and builds a closed-loop motion model of the unmanned aerial vehicle with track and altitude maintenance capability based on a nonlinear mathematical model of the quadrotor unmanned aerial vehicle; on the other hand, the cruising altitude layer is determined according to the flight heading of the unmanned aerial vehicle, so that the airspace layering effect is realized, and the flight heading is designed according to the flight profile of vertical take-off, fixed altitude cruising and vertical landing, so that the whole simulation verification process of the unmanned aerial vehicle in low-altitude operation is completed.
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The foregoing and/or other advantages of the invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings and detailed description.
FIG. 1 is a schematic diagram of a ground coordinate system;
FIG. 2 is a schematic diagram of a nonlinear dynamic inverse control law;
FIG. 3 is a low-altitude spatial domain layering schematic;
FIG. 4 is a schematic illustration of a flight profile based on layered airspace;
FIG. 5 is a simulated three-dimensional flight path diagram of a four-rotor unmanned aerial vehicle running, with three-axis coordinates representing positions of the unmanned aerial vehicle in three directions, respectively;
fig. 6 is a simulated three-dimensional flight path diagram of a four-frame four-rotor unmanned aerial vehicle running simultaneously, with three-axis coordinates representing positions of the unmanned aerial vehicle in three directions.
Detailed Description
First, six degrees of freedom modeling is performed on a four-rotor unmanned aerial vehicle, and fig. 1 is a schematic diagram of a ground coordinate system: origin of coordinate system O b Is arranged at the gravity center of the unmanned aerial vehicle, o b x b The shaft points to the direction of the machine head in the symmetry plane of the four-rotor unmanned aerial vehicle, o b z b The axis is in the symmetry plane of the four rotors and is perpendicular to o b x b Axially downwards and then according to the right hand rule o is determined b y b A shaft. Fig. 1 is a schematic diagram of a four-rotor unmanned aerial vehicle body coordinate system: origin O of coordinate axis e Is arranged at the gravity center of the unmanned aerial vehicle, o e x e The axis points to north o e z e The axis plumb is downward and then o is determined according to the right hand rule e y e The axis is directed to the east.
According to the flight mechanics knowledge, a nonlinear equation set required by the modeling of the four-rotor unmanned aerial vehicle is as follows:
(1) Four rotor tension equations:
in U i And omega i (i=1, 2,3, 4) represents the rotor tension and the rotation speed of the quadrotor, respectively, and Ω is a rotation speed coefficient related to the torque generated by the propeller.
(2) Four rotor dynamics equations:
wherein m represents the mass of the quadrotor unmanned aerial vehicle, g represents the gravitational acceleration, X, Y, Z represents the unmanned aerial vehicle coordinate position, p, q, r represent the unmanned aerial vehicle roll, pitch and yaw angular velocities respectively, phi, theta and ψ represent the unmanned aerial vehicle roll angle, pitch angle and yaw angle respectively, I XX 、I YY And I ZZ Representing rotational inertia of unmanned aerial vehicle, I R Representing the moment of inertia of the rotor shaft.
Aiming at the flight path maintenance and altitude maintenance capability of a four-rotor unmanned aerial vehicle in the cruising process, the invention designs the flight control law of the unmanned aerial vehicle by adopting a Nonlinear Dynamic Inversion (NDI) method, and the basic structure of the flight control law is shown in figure 2 and consists of a flight path instruction module, a flight path loop, a gesture angle loop, an angular velocity loop, a propeller rotating speed distribution module and a six-degree-of-freedom four-rotor mathematical model respectively, wherein the flight path loop, the gesture angle loop, the angular velocity loop and the propeller rotating speed distribution module are built by the control law design method related to the patent. If the control law is designed by adopting the traditional PID gain method, the design period is long, and the stability of the flight control system of the aircraft in different altitudes and heading is difficult to ensure. Among the various parameter variables of the unmanned aerial vehicle, the attitude variable belongs to the variable with slower change, including the roll angle, the pitch angle, the yaw angle and the like, and the angular velocity variable belongs to the variable with faster change, including the pitch, the roll and the yaw angular velocity. In the nonlinear dynamic inverse control structure, a three-axis angular velocity instruction is obtained by resolving a gesture instruction through a control law slow variable loop, a control surface instruction is obtained by resolving an input fast variable loop, and the control surface instruction is obtained by resolving a control surface actuator link and is input into a six-degree-of-freedom nonlinear model of the unmanned aerial vehicle, so that a flight state at the next moment is obtained.
The control loop design method referred to in fig. 2 is described in turn below.
The track loop inputs instructions as target tracks, and the output instructions as target roll angle, target pitch angle and pull force U 1 . The loop first calculates a target line speed according to the position error, and the calculation formula is as follows:
in the formula, the vector P= [ X, Y, Z] T And the current position coordinates of the four rotors are represented, and the subscript c represents an instruction. Omega p A gain matrix representing the position error affects the response speed of the control system.
Similarly, the linear acceleration may be calculated by the following equation:
in the vectorRepresenting the three axis acceleration.
According to the dynamics equation of the four-rotor unmanned aerial vehicle, the tension U can be obtained 1 Relationship with linear acceleration:
further, the target roll angle may be calculated from the following equation:
the target pitch angle can then be found:
the attitude angle loop inputs instructions as a target roll angle, a pitch angle and a yaw angle, and the output instructions are target triaxial angular speed. The invention uses a theoretical derivation method to solve the control matrices F and G, and can obtain according to the flight mechanics knowledge:
the method is available in the form of a nonlinear system:
thus, the target triaxial angular velocity can be calculated from the following equation:
in the middle of attitude The bandwidth matrix representing the attitude angle error affects the response speed of the attitude angle loop. The target angular velocity instruction obtained by the loop directly enters the next loop.
The input instruction of the angular velocity loop is a target angular velocity instruction transmitted by the previous loop, and the output instruction is a pulling force U 2 、U 3 And U 4 . According to four rotor unmanned aerial vehicle kinematics equation, can arrange into:
and then can obtain:
thus, the target tension can be calculated from the following equation:
in the middle of force The bandwidth matrix representing the angular velocity error affects the response speed of the angular velocity loop. Target tension instruction obtained by the loop and U obtained by the position loop 1 The command enters the rotor speed distribution module.
The rotating speed distribution module inputs a command to obtain a target pulling force according to a control law, and outputs the command to obtain the rotating speed of the multiple rotors. The four-rotor tension equation can be calculated:
so far, the rotating speeds of the four rotors are all obtained, and the four-rotor unmanned aerial vehicle can directly enter a kinematic model of the four-rotor unmanned aerial vehicle.
Fig. 3 is a schematic diagram of spatial layering. The airspace layering method is that the airspace to be layered is a low-altitude airspace with the altitude of more than 40 meters and less than 120 meters, the airspace is divided into four layers according to the flying heading, and the height of each layer is 20 meters. Through unifying unmanned aerial vehicle flight course in every layer of air space, keep high interval, reduce unmanned aerial vehicle collision risk.
Fig. 4 is a schematic view of a flight profile based on a layered airspace, wherein first, the cruising altitude is determined according to the flight heading of an unmanned aerial vehicle, an altitude command is input to the unmanned aerial vehicle, and the unmanned aerial vehicle vertically takes off from a take-off point. After reaching the cruising altitude, converting the flight mode into flat flight, inputting a flight path instruction, and enabling the unmanned aerial vehicle to directly and flatly fly according to the direction of the target, and keeping the flight altitude in a specified altitude layer. After reaching and falling directly over the point, unmanned aerial vehicle switches the flight mode and is fallen, inputs 0 altitude command, and unmanned aerial vehicle begins to reduce the altitude, finally falls on ground. Through the vertical take-off and landing method, the unmanned aerial vehicle is prevented from crossing other height layers to the greatest extent, and therefore flight safety is guaranteed.
Fig. 5 is a three-dimensional track diagram of a single-frame drone operating according to the present invention, and fig. 6 is a three-dimensional track diagram of a four-frame quad-rotor drone operating simultaneously according to the present invention. The attached drawings illustrate the complete process of taking off, landing and cruising operation of a plurality of unmanned aerial vehicles in a layered airspace.
In summary, according to the verification method for the operation simulation of the quadrotor unmanned aerial vehicle in the low-altitude layered airspace, provided by the invention, the nonlinear mathematical modeling of the quadrotor unmanned aerial vehicle is completed according to the flight mechanics knowledge, and the track maintenance and altitude maintenance control law of the unmanned aerial vehicle is designed based on the nonlinear dynamic inverse method; according to the four-rotor tension equation, the rotating speeds of all the rotors are calculated and distributed; further, the low-altitude airspace suitable for flight with the flight heading of more than 40 meters and less than 120 meters is divided in a layering manner; then, designing a corresponding flight profile according to the running airspace; based on the flight task, the flight instructions from take-off to cruising to landing of the four-rotor unmanned aerial vehicle are actually set, the closed loop operation simulation of the whole process is finally completed, the problem that multiple unmanned aerial vehicles simultaneously operate and simulate in the same airspace is solved, and the verification problem of the unmanned aerial vehicle operation simulation in a low-altitude layered airspace is effectively solved.
The invention provides a verification method for operating simulation of a quadrotor unmanned aerial vehicle in a low-altitude layered airspace, and the method and the way for realizing the technical scheme are numerous, and the above description is only a preferred embodiment of the invention, and it should be pointed out that a plurality of improvements and modifications can be made to those skilled in the art without departing from the principle of the invention, and the improvements and modifications are also regarded as the protection scope of the invention. The components not explicitly described in this embodiment can be implemented by using the prior art.
Claims (8)
1. The verification method for the four-rotor unmanned aerial vehicle running simulation in the low-altitude layered airspace is characterized by comprising the following steps of:
step 1, determining a coordinate system required by simulation and establishing a nonlinear mathematical model of the four-rotor unmanned aerial vehicle;
step 2, building a four-rotor track, a gesture and an angular velocity flight control law based on a nonlinear dynamic inverse method;
step 3, distributing the rotating speed of the propeller according to the rotor wing tension obtained by solving the control law;
the step 3 comprises the following steps: the input instruction of the track loop is a target track, and the output instruction is a target roll angle, a target pitch angle and a tension component U 1 The method comprises the steps of carrying out a first treatment on the surface of the Firstly, calculating the target line speed according to the position error, wherein the calculation formula is as follows:
in the formula, the vector P= [ X, Y, Z] T Representing the current position coordinates of four rotors, P c The input coordinate instruction is represented as such,a derivative instruction of the four-rotor unmanned aerial vehicle coordinate to time is obtained through calculation; omega p Gain matrix, ω, representing position error x ，ω y And omega z The three direction coordinate instruction gains of X, Y and Z are respectively expressed;
the linear acceleration is calculated by the following equation:
in the vectorRepresenting the triaxial acceleration;
according to the dynamics equation of the four-rotor unmanned aerial vehicle, the tension U is obtained 1 Relationship with linear acceleration:
wherein g represents a gravitational acceleration; the target roll angle phi is calculated from the following equation c ：
Wherein psi is c Representing the input target course angle, and obtaining the target pitch angle theta c ：
The attitude angle loop inputs instructions as a target rolling angle, a pitch angle and a yaw angle, and outputs instructions as a target triaxial angular speed, and the attitude angle loop is obtained according to flight mechanics knowledge:
sorting into a nonlinear system form:
wherein F is 1 And G 1 Representing the state and control matrix, respectively, the target three-axis angular velocity is calculated from the following equation:
wherein p is c 、q c 、r c Respectively representing the calculated roll angle, pitch angle and yaw angle instructions omega attitude Bandwidth matrix, ω, representing attitude angle error φ ，ω θ And omega ψ Gains respectively representing unmanned aerial vehicle roll angle, pitch angle and yaw angle instructions; the target angular velocity instruction obtained by the loop directly enters the next loop;
the input instruction of the angular velocity loop is a target angular velocity instruction transmitted by the previous loop, and the output instruction is a tension component U 2 、U 3 And U 4 The method comprises the steps of carrying out a first treatment on the surface of the According to the four-rotor unmanned aerial vehicle kinematics equation, the four-rotor unmanned aerial vehicle is arranged as follows:
in the method, in the process of the invention,the derivatives of the roll angle speed, the pitch angle speed and the yaw angle speed with respect to time, namely the triaxial angular acceleration, are respectively expressed, and the following results are obtained:
wherein F is 2 And G 2 Representing the state and control matrix, respectively, calculated by the following equationStandard tension:
wherein force represents a bandwidth matrix of angular velocity errors; target tension instruction obtained by the loop and U obtained by the position loop 1 The command enters a control law endmost rotor rotation speed distribution module;
the rotor rotation speed distribution module inputs a target tension which is obtained by a control law, outputs a multi-rotor rotation speed, and obtains according to a four-rotor tension equation:
thereby obtaining the rotation speeds of the four rotors;
step 4, layering the empty domain;
step 5, designing a flight profile of the unmanned aerial vehicle according to the layered airspace, wherein the flight profile comprises a vertical take-off stage, a cruising stage and a vertical landing stage of the unmanned aerial vehicle;
and 6, carrying out simulation verification.
2. The method according to claim 1, wherein in step 1, the determination of the coordinate system required for the simulation is defined as follows:
body coordinate system: origin of coordinate system O b Is arranged at the gravity center of the unmanned aerial vehicle, o b x b The shaft points to the direction of the machine head in the symmetry plane of the four-rotor unmanned aerial vehicle, o b z b The axis is in the symmetry plane of the four rotors and is perpendicular to o b x b Axially downwards and then according to the right hand rule o is determined b y b A shaft;
ground coordinate system: origin O of coordinate axis e Is arranged at the gravity center of the unmanned aerial vehicle, o e x e The axis points to north o e z e The axis plumb is downward and then o is determined according to the right hand rule e y e The axis is directed to the east.
3. The method of claim 2, wherein in step 1, the building a non-linear mathematical model of the quadrotor unmanned aerial vehicle comprises building the following equation:
four rotor tension equations:
in U i And omega i Respectively representing the rotor tension and the rotation speed of the ith rotor, i=1, 2,3,4, l represents a multi-rotor tension arm, C t And C q The dimensionless tension coefficient and the torque coefficient of the propeller are respectively represented, and omega is a rotating speed coefficient related to the torque generated by the propeller;
four rotor dynamics equations:
where m represents the mass of the quadrotor unmanned aerial vehicle, g represents the gravitational acceleration, X, Y, Z represents the unmanned aerial vehicle coordinate position,representing the derivative of coordinates with respect to time, i.e. unmanned ground speed,/->Representing the second derivative of coordinates with respect to time, namely the triaxial acceleration of the unmanned aerial vehicle, p, q and r respectively represent the roll, pitch and yaw angular velocities of the unmanned aerial vehicle, phi, theta and psi respectively represent the roll angle, pitch angle and yaw angle of the unmanned aerial vehicle, I XX 、I YY And I ZZ Respectively represent the triaxial moment of inertia of the unmanned aerial vehicle, I R Representing the moment of inertia of the rotor shaft.
4. A method according to claim 3, wherein step 2 comprises:
for a multiple-input multiple-output nonlinear system, the following equation is established:
order theThen:
u＝G -1 (x)(-F(x)+K c (x c -x))
wherein x represents a state quantity vector, y represents an output vector, u represents a control quantity vector, and x c Representing a target control quantity matrix, K c A matrix of gain coefficients is represented and,the rate of change of the state quantity with respect to time is represented by F (x), the state matrix of the system is represented by G (x), the control matrix of the system is represented by H (x), and the functional relationship between x and y is represented by H (x).
5. The method of claim 4, wherein in step 2, the following input-output variable matrix is used:
the rotor rotation speed distribution module inputs the variables: four rotor tension components;
rotor speed distribution module output variable: four rotor speeds;
angular velocity loop input variable: a pitch angle speed, a roll angle speed, and a yaw angle speed command;
angular velocity loop output variable: the pulling force of the three rotors;
attitude angle ring input variable: a three axis acceleration command;
attitude angle ring output variable: roll angle, pitch angle, yaw angle.
6. The method of claim 5, wherein step 4 comprises: dividing airspace of more than 40 meters and less than 120 meters based on flight heading, and dividing four altitude layers in total by taking every 90-degree heading as a unit.
7. The method of claim 6, wherein step 5 comprises: the unmanned aerial vehicle takes off from the ground, vertically rises to a designated height layer, cruises at a fixed height in the height layer, and vertically falls to the ground after reaching the position right above the destination.
8. The method of claim 7, wherein step 6 comprises: inputting a height instruction into a four-rotor unmanned aerial vehicle nonlinear mathematical model to perform take-off simulation; after reaching the cruising altitude, inputting a flight path instruction into a four-rotor unmanned aerial vehicle nonlinear mathematical model to carry out cruising stage simulation; after the landing command reaches the upper air of the destination, the landing command is input into a nonlinear mathematical model of the four-rotor unmanned aerial vehicle, and landing stage simulation is developed.
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