CN-122018559-A - Event-triggered self-locking-prevention multi-four-rotor safety formation control method and system

CN122018559ACN 122018559 ACN122018559 ACN 122018559ACN-122018559-A

Abstract

A multi-four-rotor safety formation control method and system based on event triggering and self-locking comprise the steps of building an underactuated four-rotor unmanned aerial vehicle power model under the condition of external uncertainty, building a multi-four-rotor unmanned aerial vehicle formation, building an expected formation track model, designing collision avoidance constraints among the multi-four-rotor unmanned aerial vehicles, designing an outer ring formation controller based on event triggering, generating expected angular speed and angular acceleration of the four-rotor unmanned aerial vehicle by adopting a designed differential flattening method, and designing a Litsea algebraic attitude controller for realizing global attitude stability and compensating attitude uncertainty in a limited time. The invention adopts a control barrier function to realize safety constraint, including collision prevention and direct collision prevention of a robot, and aims to avoid self-locking of the output of the control barrier function caused by the fact that the control barrier function is in local optimum, thereby causing failure of safety formation.

Inventors

LIN JIE
YANG FENG
MO YANG
WANG YAONAN
ZHANG HUI
LIU MIN

Assignees

湖南大学

Dates

Publication Date: 20260512
Application Date: 20260408

Claims (10)

1. The multi-four-rotor safety formation control method based on event triggering and self-locking is characterized by comprising the following steps of: s1, establishing an underactuated quadrotor unmanned aerial vehicle dynamic model under the condition of external uncertainty, wherein the underactuated quadrotor unmanned aerial vehicle dynamic model comprises a translational dynamic model and a rotational dynamic model, establishing a multi-quadrotor unmanned aerial vehicle formation based on a pilot-follower structure, and constructing an expected formation tracking track; S2, designing an outer ring formation controller based on event triggering, solving the self-locking problem of the multi-quad-rotor unmanned aerial vehicle according to the outer ring formation controller, inputting the space three-dimensional position of the quad-rotor unmanned aerial vehicle in a desired formation tracking track into the outer ring formation controller, generating the net thrust of the quad-rotor unmanned aerial vehicle, and inputting the net thrust into a translational dynamics model to realize translational control of the multi-quad-rotor unmanned aerial vehicle; S3, designing a differential flattening method, and mapping and generating expected angular speed and expected angular acceleration of the four-rotor unmanned aerial vehicle according to the differential flattening method; S4, designing a supercoiled observer, designing an inner ring observer according to the supercoiled observer, then constructing a gesture controller according to the inner ring observer, the expected angular speed and the expected angular acceleration of the quadrotor unmanned aerial vehicle, generating moment input in real time by using the gesture controller, and substituting the moment input into a rotation dynamics model to realize rotation control of the quadrotor unmanned aerial vehicle.
2. The multi-quad rotor safety formation control method based on event-triggered anti-self-locking according to claim 1, wherein the step S1 specifically comprises the following steps: S11, establishing an underactuated four-rotor unmanned aerial vehicle dynamic model under the condition of external uncertainty, wherein the model comprises a translational dynamics model and a rotational dynamics model, the translational dynamics model comprises a position dynamics model and a speed dynamics model, and the rotational dynamics model comprises a gesture dynamics model and an angular speed dynamics model; S12, establishing a multi-quad-rotor unmanned aerial vehicle formation based on a pilot-follower structure, wherein the multi-quad-rotor unmanned aerial vehicle formation comprises a virtual pilot and a plurality of followers, the multi-quad-rotor unmanned aerial vehicle formation expected formation is determined by expected position deviation delta ij between an ith and a jth quad-rotor unmanned aerial vehicles, delta ij =δ i -δ j , delta i represents expected relative positions between the virtual pilot and the ith follower, delta j represents expected relative positions between the virtual pilot and the jth follower, and expected track of a multi-quad-rotor unmanned aerial vehicle formation center is recorded as ∈ ; Representing a real set; S13, constructing a four-rotor unmanned aerial vehicle to achieve expected formation, and simultaneously keeping an expected formation tracking track corresponding to a time-invariant formation mode; s14, designing collision prevention constraint among the four-rotor unmanned aerial vehicle.
3. The multi-quad rotor safety formation control method based on event-triggered anti-self-locking according to claim 2, wherein expressions of the position dynamics model, the speed dynamics model, the attitude dynamics model and the angular speed dynamics model in S11 are as follows: (1) (2) (3) (4) Wherein, the Representing the spatial three-dimensional position of the ith quadrotor unmanned aerial vehicle; , A point above the parameter represents the first derivative of the parameter; Representing the speed of the ith quad-rotor unmanned helicopter; And Respectively representing the net thrust and moment inputs of the ith quadrotor unmanned, Representing a rotation matrix of the ith quad-rotor unmanned helicopter; is a constant vector which is used for the data processing, Representing a transpose of the matrix; gravitational acceleration; And Representing the total damping of the external disturbance and the unmodeled dynamics acting on the translational and rotational movements, respectively; And The mass and normal symmetrical inertia matrix of the ith four-rotor unmanned aerial vehicle are respectively; indicating the angular velocity of the ith four-rotor unmanned aerial vehicle Representing an operation of converting the vector into an antisymmetric matrix; indicating angular velocity A corresponding antisymmetric matrix; the expression of the desired formation tracking track in S13 is specifically as follows: (5) Wherein t represents the time, and the time, Representing a very small positive constant; Means "arbitrary"; represents a positive integer; the four-rotor unmanned aerial vehicle collision prevention constraint in the S14 is specifically as follows: (6) Wherein, the Is the minimum collision-free distance between adjacent quad-rotor unmanned vehicles.
4. The multi-quad rotor safety formation control method based on event-triggered anti-self-locking according to claim 3, wherein the step S2 specifically comprises the following steps: s201, reconstructing a speed dynamics model in an underactuated four-rotor unmanned aerial vehicle dynamic model to obtain a reconstructed speed dynamics model; S202, designing a robust filter to completely counteract the first custom variable Influence of the reconstructed velocity dynamics model, and designing an initial robust compensator by combining a robust filter; S203, constructing a first custom variable Is calculated according to the formula (I); S204, the first custom variable is processed Substituting the calculated value into the initial robust compensator to obtain an optimized robust compensator; S205, defining formation tracking errors of each four-rotor unmanned aerial vehicle; S206, calculating the time derivative of the formation tracking error of each quadrotor unmanned aerial vehicle ; S207, utilizing formation tracking error Time derivative Designing nominal formation controllers ; S208, utilizing a nominal formation controller Rewriting a position dynamics model and a speed dynamics model in an underactuated four-rotor unmanned aerial vehicle dynamics model to obtain a position subsystem dynamics model And robust compensation input Difference between ; S209, encoding collision avoidance targets among the multi-four-rotor unmanned aerial vehicle as a safety set for avoiding collision And according to the security set Constructing a control barrier function; S210, combining control barrier functions and utilizing nominal formation controllers External disturbance And robust compensation input Difference between Constructing a safety constraint; S211, constructing an obstacle function aiming at the ith four-rotor unmanned aerial vehicle and the kth obstacle; S212, defining relative speed for dynamic obstacle ; S213, optimizing the safety constraint by using the barrier function to obtain an optimized safety constraint; S214, correcting the thrust of the ith four-rotor unmanned aerial vehicle based on the optimized safety constraint to obtain an optimal solution of the corrected thrust; s215, when the control barrier function obtains the optimal control input When the system falls into local optimum, a formation system formed by a plurality of quadrotor unmanned aerial vehicles can generate a self-locking phenomenon of a control barrier function, namely the formation system always meets safety constraint, but the control input is restrained and dominant due to the degradation of a feasible control space, and the formation system falls into a stagnation state and cannot continue to propel a task target; s216, designing a switching control strategy of jump-out self-locking so as to assist a control barrier function used by the formation system to jump out self-locking; s217, designing a robust formation controller for each four-rotor unmanned aerial vehicle, and then designing an event trigger control rate according to the robust formation controller and an optimal solution of the modified thrust; s218, combining intermediate control input to be designed Rotation matrix of four rotor unmanned aerial vehicle Quality of four rotor unmanned aerial vehicle Designing an event trigger formation controller; The construction of the outer ring formation controller is completed, the outer ring formation controller comprises a robust filter, a nominal formation controller, a control barrier function and an event trigger formation controller which are sequentially connected, and then the event trigger formation controller is utilized to generate the net thrust of the ith four-rotor unmanned aerial vehicle Inputting the translational dynamic model to realize translational control of a plurality of quadrotor unmanned aerial vehicles; S219, giving a reference yaw angle of each four-rotor unmanned aerial vehicle According to the reference yaw angle Calculating expected unit direction vector of each quadrotor unmanned aerial vehicle on the x axis of a machine body coordinate system Then calculating expected unit direction vector of each quadrotor unmanned aerial vehicle on the z-axis of the machine body coordinate system according to the robust formation controller ; S220, defining the expected unit direction vector of each quadrotor unmanned aerial vehicle on the y axis of the machine body coordinate system as ; S221, constructing expected postures of each four-rotor unmanned aerial vehicle according to expected unit direction vectors of each four-rotor unmanned aerial vehicle on x, y and z axes 。
5. The multi-quad rotor safety formation control method based on event-triggered anti-self-locking according to claim 4, wherein the speed dynamics model reconstructed in S201 is specifically as follows: (7) Wherein, the Representing an intermediate control input to be designed, the intermediate control input First custom variable The expressions of (2) are as follows: (8) (9) Wherein, the Representing an expected rotation matrix corresponding to the expected formation of the ith four-rotor unmanned aerial vehicle; Is a coupling term between a velocity dynamics model and a gesture dynamics model when When this coupling term will disappear; the initial robust compensator in S202 is specifically: (10) Wherein, the Representing a robust compensation input; a robust filter is represented by the representation, Representing three components of a robust filter, and component sequence numbers S is Laplacian; Is a normal number to be determined; the first custom variable in S203 The formula of (c) is as follows: (11) the robust compensator optimized in S204 is specifically as follows: (12) Wherein, the Are all robust filter states; representing three positive constants; The formation tracking error of each quadrotor unmanned aerial vehicle in S205 is specifically as follows: (13) Wherein, the Indicating a formation tracking error of the ith four-rotor unmanned aerial vehicle; the calculation formula of the time derivative of the formation tracking error of each quadrotor unmanned aerial vehicle in S206 is as follows: (14) Wherein, the A time derivative representing a formation tracking error of the ith quad-rotor unmanned aircraft; the nominal formation controller in S207 The method comprises the following steps: (15) Wherein, the For a scalar coupling gain, A positive parameter matrix is determined; representing a difference in spatial three-dimensional position between the ith and jth quadrotor drones; representing a speed differential between the ith and jth quad-rotor drones; two points on a parameter represent the second derivative of the parameter; representing a connection weight between the virtual pilot and the ith quad-rotor unmanned helicopter; representing connection weights between the ith and jth quad-rotor drones; the location subsystem dynamics model in S208 is specifically as follows: (16) Wherein, the Represents a second custom variable, an ; Representing a third custom variable, and ; Represent a fourth custom variable, an ; Represents a fifth custom variable, and ; Representing external disturbances of an ith quad-rotor unmanned helicopter And robust compensation input A difference between them; The security set in S209 The expression of (2) is as follows: (17) Wherein, the Is a control barrier function of relative order two, and the expression of the control barrier function is specifically as follows: (18) The safety constraint in S210 is specifically as follows: (19) Wherein, the Representing a first intermediate variable; Representing a second intermediate variable; represents a third intermediate variable, and the third intermediate variable The formula of (2) is as follows: (20) the calculation formula of this term is: ; In the formula (19) The calculation formula of this term is: ; the obstacle function in S211 is specifically as follows: (21) Wherein, the Representing a distance relationship between the ith quadrotor drone and the kth obstacle; representing a distance between the ith quadrotor drone and the kth obstacle; representing the safe distance from the ith quadrotor unmanned aerial vehicle to the kth obstacle; representing the radius of the obstacle; The relative speed in S212 The expression of (2) is as follows: (22) Wherein, the Representing the speed of obstacle k; the safety constraint after optimization in S213 is specifically as follows: (23) wherein the fourth intermediate variable The formula of (2) is as follows: (24) the corrected thrust expression in S214 is as follows: (25) Wherein, the Represents the optimal solution of the corrected thrust force, Representing the thrust before correction, requiring an optimal solution; constraint of the corrected thrust expression: wherein Representing a sixth custom variable; The seventh custom variable is represented, and the calculation formulas of the seventh custom variable and the seventh custom variable are respectively as follows: ; ; , ; Wherein, the Representing the total number of obstacles; The feasible margin calculation formula in S215 is as follows: (26) Wherein, the Representing a viable margin; and the duration of self-locking exceeds Judging that the vehicle is self-locking; Representing a viable margin threshold; Representing a preset self-locking duration threshold; The robust formation controller in S217 is specifically as follows: (27) Wherein, the Representing an event-triggered control rate for achieving a desired tracking trajectory for a nominal translational dynamics model, a robust compensation input For suppressing external disturbances Influence on translational dynamics model; event-triggered control rate The formula of (2) is as follows: ; Wherein, the Representing a minimum directional disturbance input; the calculation formula of the event triggering formation controller in S218 is as follows: (28) the desired unit direction vector in S219 The formula of (2) is as follows: ; the desired unit direction vector in S219 The formula of (2) is as follows: (29) the desired unit direction vector in S220 The formula of (2) is as follows: (30) Each four-rotor unmanned aerial vehicle expected gesture in S221 The formula of (2) is as follows: (31)。
6. The event-triggered self-locking-based multi-quad-rotor safety formation control method according to claim 5, wherein the switching control strategy of the jump-out self locking in S216 is specifically as follows: increasing minimum directional disturbance input at event trigger level The minimum directional disturbance input is the vector that can increase the feasible margin by solving the minimum directional disturbance input The formula is as follows: (32) ; Wherein, the Representing a disturbance input variable; Represents a relaxation variable; representing maximum allowable disturbance, minimum directional disturbance input After the solving is completed, the self-locking state of the four-rotor unmanned aerial vehicle is jumped out.
7. The multi-quad rotor safety formation control method based on event-triggered anti-self-locking according to claim 6, wherein the step S3 specifically comprises the following steps: s31, giving a flat output space as Wherein three points on the parameter represent the third derivative of the parameter, four points on the parameter represent the fourth derivative of the parameter, and the third derivatives of the three-dimensional space position of the quadrotor unmanned aerial vehicle are respectively constructed Is calculated according to the formula (I); s32, giving intermediate variable And take intermediate variables Third derivative substituted into three-dimensional position of four-rotor unmanned aerial vehicle In the calculation of (a), an intermediate variable is obtained Is calculated according to the formula (I); s33, intermediate variable Transforming the calculation formula of the reference angular velocity to obtain a calculation formula of the reference angular velocity; S34, in the intermediate variable Calculated medium jerk of (2) Third derivative for replacing spatial three-dimensional position of quadrotor unmanned aerial vehicle Obtaining the eighth custom variable Is calculated according to the formula (I); s35, for fourth intermediate variable Both sides and rotation components of the calculation of (a) Dot product operation is carried out, and the net thrust first derivative is obtained by solving ; S36 first derivative of net thrust Deriving to obtain the second derivative of the net thrust ; S37, obtaining the first derivative of the net thrust by solving Second derivative of net thrust Substituted into eighth custom variable In the calculation formula of (2), an eighth custom variable is obtained ; S38, utilizing eighth custom variable And calculating to obtain the expected angular acceleration of the four-rotor unmanned aerial vehicle.
8. The event-triggered anti-self-locking multi-quad-rotor safety formation control method according to claim 7, wherein the third derivative in S31 Fourth order derivative The calculation formula of (2) is as follows: (33) (34) the intermediate variable in S32 The formula of (c) is as follows: (35) Wherein, the Representing the rotation component of the ith four-rotor unmanned aerial vehicle in the z-axis direction of the machine body coordinate system; representing the second derivative of the desired trajectory of the formation center; The calculation formula of the desired angular velocity in S33 is specifically as follows: (36) Wherein, the Indicating a desired angular velocity; representing the rotation component of the ith quadrotor unmanned aerial vehicle in the y-axis direction of the body coordinate system; representing the rotation component of the ith quadrotor unmanned aerial vehicle in the x-axis direction of the body coordinate system; The eighth custom variable in S34 The formula of (c) is as follows: (37) The first derivative of the net thrust in S35 The formula of (c) is as follows: (38) The second derivative of the net thrust in S36 The formula of (c) is as follows: (39) Wherein, the A derivative representing jerk; the calculation formula of the desired angular acceleration in S38 is specifically as follows: (40) Wherein, the Indicating the desired angular acceleration of the ith quad-rotor drone.
9. The multi-quad rotor safety formation control method based on event-triggered anti-self-locking according to claim 8, wherein the step S4 specifically comprises the following steps: S41, providing a supercoiled observer for identifying and compensating the uncertainty of an inner ring in a limited time, wherein the inner ring refers to an attitude error, and the supercoiled observer has the following expression: (41) Wherein, the Representing an error variable; indicating angular velocity Is a function of the estimated value of (2); S42, designing an inner ring observer by utilizing the supercoiled observer Inner ring observer The expression of (2) is as follows: (42) Wherein, the And Gain for normal number; Representing error variables Is a derivative of (2); Representation of Is a derivative of (2); S43, defining a rotation matrix error Error of rotation matrix The expression of (2) is as follows: (43) S44, according to the rotation matrix error Defining logarithmic configuration posing errors on lie algebra space Logarithmic configuration attitude error The expression of (2) is as follows: (44) Wherein, the Representing the transformation of the anti-symmetric matrix in brackets into a three-dimensional vector; S45, defining related speed errors Related velocity error The expression of (2) is as follows: (45) S46, logarithmic configuration attitude error Related speed error And obtaining a time derivative to obtain an attitude error dynamics model, wherein the expression of the attitude error dynamics model is as follows: ; (46) Wherein, the Representing a fifth intermediate variable; Represents a sixth intermediate variable; Represents a seventh intermediate variable; then solving according to the expression of the attitude error dynamics model 、 The calculation formula is as follows; (47) (48) Wherein, the Representing logarithmic configuration posing errors Is an antisymmetric matrix of (a); Representing a binary norm; Representing a 3x3 identity matrix; s47, controlling the part according to the nominal And inner ring observer Constructing a gesture controller, wherein the calculation formula of the gesture controller is specifically as follows: (49) Wherein, the Representing the moment input and the moment of force, Representing a nominal control input The formula of (c) is as follows: (50) Wherein, the And Gain for normal number; s49, combining the gesture controller and the supercoiled observer to construct an inner ring controller, and generating moment input in real time by using the inner ring controller And substituting the attitude uncertainty into a rotation dynamics model to realize rotation control of the multi-quad-rotor unmanned helicopter and compensate attitude uncertainty in a limited time.
10. A multi-quad-rotor safety formation control system based on event-triggered anti-self-locking, characterized by comprising a multi-quad-rotor unmanned aerial vehicle configured or executing a multi-quad-rotor safety formation control method based on event-triggered anti-self-locking as claimed in any one of claims 1 to 9.

Description

Event-triggered self-locking-prevention multi-four-rotor safety formation control method and system Technical Field The invention relates to the technical field of multi-unmanned aerial vehicle safety formation, in particular to a multi-four-rotor wing safety formation control method and system based on event triggering and self-locking prevention. Background In the engineering field, the four-rotor unmanned aerial vehicle has been widely applied to various scenes such as inspection, mapping, emergency response and the like by virtue of the advantages of strong maneuverability, small volume, high task adaptability and the like. Compared with a single aircraft, the four-rotor formation flying system has the remarkable advantages of lower cost, higher efficiency and stronger fault tolerance in complex tasks such as collaborative transportation, environment monitoring and collaborative rescue, and therefore becomes a research hot spot in the unmanned system field. However, as the application scenario is continuously expanded from an ideal environment to a real complex environment, the multi-four rotor system faces a plurality of engineering challenges in the process of formation tracking and cooperative control. On one hand, factors such as uncertain disturbance of external environment, incomplete model, saturation of an actuator and the like seriously affect formation control performance, and on the other hand, when a plurality of unmanned aerial vehicles fly in a dense coordination mode, safety collision prevention constraint between the unmanned aerial vehicles and dynamic obstacles must be met at the same time. In addition, the existing formation control method based on the control barrier function is easy to cause a self-locking problem in practical application, so that the feasible solution space of the system is limited, even formation tasks fail, and the engineering applicability of the formation control method is further limited. Under the background, aiming at the dynamics characteristics of underactuation and high coupling of a four-rotor system, how to construct a distributed, safe and robust multi-rotor formation control framework in a complex uncertain environment, effectively cope with external uncertainty and actuator saturation constraint while ensuring dynamic obstacle avoidance and unmanned aerial vehicle safety collision avoidance, and become key science and technical problems to be broken through in multi-rotor system engineering application. Disclosure of Invention The invention provides a multi-four-rotor safety formation control method and system based on event triggering and self-locking prevention, which are used for solving the technical problems mentioned in the background art. In order to achieve the above purpose, the technical scheme of the invention is realized as follows: The invention provides a multi-four-rotor wing safety formation control method based on event triggering and self-locking prevention, which comprises the following steps: s1, establishing an underactuated quadrotor unmanned aerial vehicle dynamic model under the condition of external uncertainty, wherein the underactuated quadrotor unmanned aerial vehicle dynamic model comprises a translational dynamic model and a rotational dynamic model, establishing a multi-quadrotor unmanned aerial vehicle formation based on a pilot-follower structure, and constructing an expected formation tracking track; S2, designing an outer ring formation controller based on event triggering, solving the self-locking problem of the multi-quad-rotor unmanned aerial vehicle according to the outer ring formation controller, inputting the space three-dimensional position of the quad-rotor unmanned aerial vehicle in a desired formation tracking track into the outer ring formation controller, generating the net thrust of the quad-rotor unmanned aerial vehicle, and inputting the net thrust into a translational dynamics model to realize translational control of the multi-quad-rotor unmanned aerial vehicle; S3, designing a differential flattening method, and mapping and generating expected angular speed and expected angular acceleration of the four-rotor unmanned aerial vehicle according to the differential flattening method; S4, designing a supercoiled observer, designing an inner ring observer according to the supercoiled observer, then constructing a gesture controller according to the inner ring observer, the expected angular speed and the expected angular acceleration of the quadrotor unmanned aerial vehicle, generating moment input in real time by using the gesture controller, and substituting the moment input into a rotation dynamics model to realize rotation control of the quadrotor unmanned aerial vehicle. Further, the step S1 specifically includes the following steps: S11, establishing an underactuated four-rotor unmanned aerial vehicle dynamic model under the condition of external uncertainty, wherein the model comprises a translati