New criterion of four-rotor unmanned aerial vehicle obstacle avoidance system based on affine formation control

Abstract

The invention discloses a four-rotor unmanned aerial vehicle obstacle avoidance system new criterion based on affine formation control. According to the method, an interference observer is designed to estimate an unknown interference true value of the quad-rotor unmanned aerial vehicle, and a corresponding anti-interference controller is provided. Besides, in order to avoid obstacles during formation flight, leader-follower affine formation control is realized by using an affine transformation method, and the leader decides the required collective formation. Finally, by means of the Lyapunov stability theorem, several sufficient criteria are established to ensure that the leaders are consistent and finally bounded at the zero speed, the constant speed and the time-varying speed, and then formation control is achieved.

Description

Technical Field

[0001] The invention relates to an affine formation control method, and in particular to a new criterion based on a quad-rotor unmanned aerial vehicle obstacle avoidance system. Background Art

[0002] Many dynamic models for quadcopter control systems are only established under a preset formation flight situation. In actual applications, the actual formation of the formation needs to change according to the size and shape of the obstacle to pass through the obstacle channel. In addition, the quadcopter formation control system may cause the communication information between the follower and the leader to be disconnected when it is subject to unknown external interference. Therefore, the discussion of the quadcopter obstacle avoidance system based on affine formation control is crucial to ensure the accurate observation of unknown external interference of the system. Based on this idea, researchers have carried out a lot of research on the quadcopter obstacle avoidance system of affine formation control under unknown interference and achieved a series of results. Summary of the invention

[0003] The purpose of the present invention is to propose a new criterion for a quadrotor unmanned aerial vehicle obstacle avoidance system based on affine formation control, which can effectively improve the performance of the quadrotor unmanned aerial vehicle control system;

[0004] The specific technical solution of the present invention is as follows: A new criterion for a quad-rotor unmanned aerial vehicle obstacle avoidance system based on affine formation control comprises the following steps:

[0005] Design a disturbance observer to estimate the unknown disturbance of the quadrotor drone and give the corresponding anti-interference compensator

[0006] Leader-follower affine formation control using an affine transformation approach, where the leader determines the desired collective formation

[0007] The Lyapunov stability criterion is established to ensure that the leader is ultimately bounded at zero speed, constant speed, and time-varying speed, thereby achieving formation control.

[0008] Under external interference, the obstacle avoidance system model of the quadrotor drone with formation affine control is as follows:

[0009]

[0010] In the formula, p i (t) and v i (t) represent the position and speed of the quadrotor drone, u i (t) represents the control input, d i (t) represents unknown external input, which can be represented by one of the following external systems

[0011]

[0012] For unknown interference d i (t), design the following disturbance observer:

[0013]

[0014] in is d i (t) is the estimated value, L1 and L2 are the unknown observer gains;

[0015] Define an intermediate variable θ i (t), the disturbance observer can be further written as

[0016]

[0017] The interference estimation error is defined as The estimated error system can be written as

[0018]

[0019] In addition, the control input u i (t) For the leader at zero speed, constant speed and time-varying speed, the

[0020]

[0021] in Control gain k v Adaptive control strategy approach;

[0022] For the above matrix Its The remaining parameters are selected as

[0023]

[0024] Inspired by the relationship between the leader and the follower in the affine definition, the expected position and expected velocity of the follower state are calculated as follows:

[0025]

[0006] The position error and velocity error are defined as The error system can be obtained as

[0027]

[0028] The formation control proof process is as follows:

[0029] C001: For the leader's formation flight control at zero speed, select the energy function of the following form:

[0030]

[0031] C002: Where P1 is an arbitrary positive definite matrix:

[0032] C003: Calculate the first-order derivative of V(t):

[0033]

[0034] C004: Based on Lyapunov stability theory, when <0, there is Then the affine formation error e pf (t), e vf (t) and the estimated error e d (t) is uniformly eventually bounded;

[0035] C005: For the leader's formation flight control at constant speed, select the energy function of the following form:

[0036]

[0037] C006: where P1 is any positive definite matrix;

[0038] C007: Calculate the first derivative of V(t):

[0039]

[0040] C008: Through Young's inequality, we know

[0041]

[0042] C009: Combining C007 and C008,

[0043]

[0044] C010: Based on Lyapunov stability theory, when Sometimes, there is Then the affine formation error e pj (t), e vf (t) and the estimated error e d (t) is uniformly eventually bounded;

[0045] C011: For the formation flight control of the leader under time-varying speed, select the energy function of the following form:

[0046]

[0047] C012: where P1 is an arbitrary positive definite matrix;

[0048] C013: Calculate the first derivative of V(t):

[0049]

[0050] C014: Based on Lyapunov stability theory, when Sometimes, there is Then the affine formation error e pf (t), e vf (t) and the estimated error e d (t) is uniformly eventually bounded. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The topological structure diagram of seven quadrotor drones includes three leaders and four followers;

[0052] Figure 2 Dynamic trajectory diagram for quadrotor drones to avoid obstacles in formation;

[0053] Figure 3 and 4 This is the dynamic trajectory diagram of the quadrotor unmanned connection acceleration;

[0054] Figure 5 and 6 This is the dynamic trajectory diagram of the quadrotor unmanned landing speed;

[0055] Figure 7 It is the dynamic trajectory diagram of controller gain adaptive control; DETAILED DESCRIPTION

[0056] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0057] A new criterion for the obstacle avoidance system of a quadrotor drone based on affine formation control includes the following steps:

[0058] Step 1: Set various system parameters;

[0059] Step 2: Set up an observer for unknown disturbance to estimate its true value;

[0060] Step 3: Set up formation control using affine transformation method;

[0061] Step 4: Set up the estimation error system;

[0062] Step 5: Set up the tracking error system;

[0063] An embodiment of the present invention is described below:

[0064] Consider a formation affine-controlled quadrotor UAV obstacle avoidance system, and its corresponding dynamic models are:

[0065]

[0066]

[0067] The topological structure of seven quad-rotor drones is shown below: Figure 1 As shown in the figure, the dynamic trajectory of the quadcopter UAV performing formation obstacle avoidance is as follows Figure 2 As shown in the figure, the dynamic trajectory of the quadcopter unmanned acceleration is as follows Figure 3 and 4 As shown in the figure, the dynamic trajectory of the quadcopter unmanned landing speed is as follows Figure 5 and 6 As shown, the dynamic trajectory of the controller gain adaptive control is shown in Figure 7 shown.

Claims

1. A new criterion for the obstacle avoidance system of a quadrotor drone based on affine formation control, characterized in that: The following steps are involved: Design a disturbance observer to estimate the unknown disturbance of the quadrotor drone and give the corresponding anti-interference compensator; Leader-follower affine formation control is achieved using an affine transformation approach, where the leader determines the desired collective formation; A Lyapunov stability criterion is established to ensure the consistent ultimate boundedness of the leader at zero speed, constant speed and time-varying speed, respectively, thereby achieving formation control.

2. The new criterion for the obstacle avoidance system of a quadrotor drone based on affine formation control according to claim 1 is characterized in that Under the interference caused by the external system, a disturbance observer is designed to estimate the unknown interference of the quadrotor drone. The specific steps are as follows: Under external interference, the obstacle avoidance system model of the quadrotor drone with formation affine control is as follows: In the formula, p i (t) and v i (t) represent the position and speed of the quadrotor drone, u i (t) represents the control input, d i (t) represents unknown external input, which can be represented by one of the following external systems In addition, for the unknown interference d i (t), design the following disturbance observer: in is d i (t) is the estimated value, L1 and L2 are the unknown observer gains; Define an intermediate variable θ i (t), the disturbance observer can be further written as The interference estimation error is defined as The estimated error system can be written as 3. According to the new criterion of the quadrotor unmanned aerial vehicle obstacle avoidance system based on affine formation control in claim 2, the leader-follower affine formation control is realized by using the affine transformation method, wherein the leader determines the required collective formation, and the specific steps are as follows: Control input u i (t) For the leader at zero speed, constant speed and time-varying speed, the in Control gain k v Adaptive control strategy approach; For the above matrix Its The remaining parameters are selected as Inspired by the relationship between the leader and the follower in the affine definition, the expected position and expected velocity of the follower state are calculated as follows: The position error and velocity error are defined as The error system can be obtained as 4. According to the new criterion of the quadcopter obstacle avoidance system based on affine formation control described in claim 3, a Lyapunov stability criterion is established to ensure that the leader is uniformly bounded at zero speed, constant speed and time-varying speed, respectively, and then realize formation control. The proof process is as follows: B001: For the leader's formation flight control at zero speed, select the energy function of the following form: B002: where P1 is an arbitrary positive definite matrix; B003: Calculate the first-order derivative of V(t): B004: Based on Lyapunov stability theory, when Sometimes, there are Then the affine formation error e pf (t), e vf (t) and the estimated error e d (t) is uniformly eventually bounded; B004: For the leader's formation flight control at constant speed, select the energy function of the following form: B005: where P1 is an arbitrary positive definite matrix; B006: Calculate the first derivative of V(t): B007: Through Young's inequality, we know B008： B009: Combining B006 and B008, B0010： B0011: Based on Lyapunov stability theory, when Sometimes, there are Then the affine formation error e pf (t), e vf (t) and the estimated error e d (t) is uniformly eventually bounded; B0012: For the formation flight control of the leader under time-varying speed, the energy function of the following form is selected: B0013: where P1 is any positive definite matrix; B0014: Calculate the first derivative of V(t): B0015: Based on Lyapunov stability theory, when Sometimes, there is Then the affine formation error e pf (t), e vf (t) and the estimated error e d (t) is uniformly eventually bounded.

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