Adaptive sliding mode cooperative guidance method for accelerated target

Abstract

The invention discloses a self-adaptive sliding mode cooperative guidance method for an accelerated target. The method comprises the following steps: establishing a relative motion model of a single target and multiple aircrafts; obtaining a state equation of the guidance system based on the relative motion model; a switching surface is set, so that the sight angle error is 0; setting a self-adaptive reaching law, and obtaining a self-adaptive guidance law in combination with the switching surface; and the aircraft flies by adopting the obtained guidance law. According to the self-adaptive sliding mode cooperative guidance method for the accelerated target, a plurality of aircrafts can intercept the same target at different expected angles, the aircrafts fly stably in the interception process, and the anti-disturbance capability is achieved.

Description

Technical Field

[0001] The invention relates to an adaptive sliding mode collaborative guidance method oriented to an acceleration target, belonging to the technical field of flight control. Background Art

[0002] For intercepting highly maneuverable and high-value targets, engineering usually adopts a multi-aircraft coordinated interception method to increase the probability of intercepting the target.

[0003] In order to improve the damage effect and interception accuracy of multiple aircraft on the target, multiple aircraft are required to meet angle constraints and overload constraints at the end of the interception, and have a certain anti-interference ability during the interception process. However, the existing guidance methods are difficult to meet the above requirements at the same time.

[0004] Due to the above reasons, it is necessary to conduct in-depth research on the existing collaborative guidance methods to solve the above problems. Summary of the invention

[0005] In order to overcome the above problems, an in-depth study was conducted and an adaptive sliding mode collaborative guidance method for acceleration target was proposed, which includes the following steps:

[0006] S1. Establish the relative motion model of single target and multiple aircrafts;

[0007] S2. Obtaining the state equation of the guidance system based on the relative motion model;

[0008] S3, setting the switching surface so that the sight angle error is 0;

[0009] S4, setting an adaptive approaching law and combining it with the switching surface to obtain an adaptive guidance law;

[0010] S5. The aircraft flies using the obtained guidance law.

[0011] In a preferred embodiment, in S1, the relative motion model is expressed as:

[0012]

[0013] Among them, the subscript i represents different aircraft, r i represents the relative line of sight distance between aircraft i and the target, represents the speed of aircraft i, represents the track angle of aircraft i, q i represents the sight angle between aircraft i and target, V T represents the speed of the target, θ T represents the target’s track angle, represents the acceleration of aircraft i, a T Indicates the acceleration of the target.

[0014] In a preferred embodiment, in S2, the system state quantity is set to x 1 =-q,

[0015] Among them, x 1 、x 2 is the system state quantity, q represents the sight angle between the aircraft and the target, is the angular velocity between the aircraft and the target.

[0016] In a preferred embodiment, the guidance system state equation is expressed as:

[0017]

[0018] Among them, u is the control quantity, which represents the component of the aircraft acceleration in the normal direction of the line of sight between the aircraft and the target; ω is the interference quantity, which represents the component of the target acceleration in the normal direction of the line of sight between the aircraft and the target; r represents the relative line of sight distance between the aircraft and the target.

[0019] In a preferred embodiment, in S3, the switching surface s is set to:

[0020]

[0021] Among them, θ f represents the desired interception angle, V M is the speed of the aircraft, λ and c are configurable parameters.

[0022] In a preferred embodiment, in S4, the adaptive reaching law is set to:

[0023]

[0024] Among them, k and ε are configurable parameters.

[0025] In a preferred embodiment, the obtained adaptive guidance law is expressed as:

[0026]

[0027] The beneficial effects of the present invention include:

[0028] (1) Multiple aircraft can intercept the same target at different desired angles;

[0029] (2) The aircraft flies with a small overload during the interception process, so that the aircraft flies smoothly when approaching the target;

[0030] (3) It has a certain anti-disturbance capability, reduces the impact of internal and external disturbances on interception accuracy, and weakens the vibration during flight. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic flow chart of an adaptive sliding mode collaborative guidance method for an acceleration target according to a preferred embodiment of the present invention is shown;

[0032] Figure 2 The simulation result of the flight trajectory of the aircraft in the embodiment is shown;

[0033] Figure 3 The simulation result of the aircraft overload curve in the embodiment is shown;

[0034] Figure 4 The simulation results of the aircraft interception angle curve in the embodiment are shown. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below through the accompanying drawings and embodiments. Through these descriptions, the characteristics and advantages of the present invention will become more clear and distinct.

[0036] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0037] According to the adaptive sliding mode collaborative guidance method for acceleration target provided by the present invention, Figure 1 As shown, the following steps are included:

[0038] S1. Establish the relative motion model of single target and multiple aircrafts;

[0039] S2. Obtaining the state equation of the guidance system based on the relative motion model;

[0040] S3, setting the switching surface so that the sight angle error is 0;

[0041] S4, setting an adaptive approaching law and combining it with the switching surface to obtain an adaptive guidance law;

[0042] S5. The aircraft flies using the obtained guidance law.

[0043] In the present invention, by setting a switching surface and an adaptive approach law, a guidance law is obtained based on a sliding mode variable structure control method, so that multiple aircraft can intercept targets at different desired angles. At the same time, the aircraft can be controlled with a smaller overload, thereby providing a good working environment for the measuring device carried on the aircraft and reducing the impact of measurement errors and external disturbances such as aerodynamic changes and meteorological conditions on interception accuracy.

[0044] In S1, the relative motion model is expressed as:

[0045]

[0046] Among them, the subscript i represents different aircraft, r i represents the relative line of sight distance between aircraft i and the target, represents the speed of aircraft i, represents the track angle of aircraft i, q i represents the sight angle between aircraft i and target, V T represents the speed of the target, θ T represents the target’s track angle, represents the acceleration of aircraft i, a T represents the acceleration of the target, and the superscript · represents the first-order derivative.

[0047] In S2, based on the relative motion model, for any aircraft, the first and second equations of the relative motion model are differentiated with respect to time to obtain:

[0048]

[0049] make:

[0050]

[0051] Substituting it into the above formula, we can get:

[0052]

[0053] Among them, u r and ω r are the components of the aircraft acceleration and target acceleration in the aircraft-target line of sight direction; u q and ω q are the components of the vehicle acceleration and the target acceleration in the normal direction of the vehicle-target line of sight, respectively. The superscript ·· indicates the second-order derivative.

[0054] In actual guidance, generally no control is applied to the aircraft in the direction of the aircraft-target line of sight. It is only necessary to ensure that the relative speed between the aircraft and the target in this direction is less than 0. It is only necessary to control the component u of the aircraft acceleration in the normal direction of the aircraft-target line of sight. r To achieve guidance, we have:

[0055]

[0056] Among them, u is the control variable and ω is the disturbance variable.

[0057] According to a preferred embodiment of the present invention, the system state quantity is set to x 1 =-q,

[0058] Among them, x 1 、x 2 is the system state quantity, q represents the sight angle between the aircraft and the target, is the angular velocity between the aircraft and the target.

[0059] Based on the above derivation, the state equation of the guidance system can be obtained:

[0060]

[0061] Among them, u is the control quantity, which represents the component of the aircraft acceleration in the normal direction of the line of sight between the aircraft and the target; ω is the interference quantity, which represents the component of the target acceleration in the normal direction of the line of sight between the aircraft and the target; r represents the relative line of sight distance between the aircraft and the target.

[0062] In S3, set the switching surface s to:

[0063]

[0064] Among them, θ f represents the desired interception angle, V M is the speed of the aircraft, λ and c are configurable parameters.

[0065] The above switching surface ensures that the overload of the aircraft is small during the interception process, and the overload constraint is achieved. During the interception, the line of sight angular rate between the aircraft and the target is 0, and the line of sight angle between the aircraft and the target is kept constant, so that the line of sight angle error is 0, so that the aircraft can attack at the desired angle θ f Hit the target.

[0066] Furthermore, according to the first term of the switching surface equation, when the aircraft flies towards the target from far to near, The value of will change from small to large, which means that the rate of zeroing of the first term will also change from slow to fast, and the meaning of the first term is exactly the interception angle constraint. Therefore, the above switching surface can achieve that when the aircraft approaches the target, its interception angle quickly approaches the expected attack angle, which is adaptive.

[0067] In S4, the adaptive reaching law is set to:

[0068]

[0069] Among them, k and ε are configurable parameters.

[0070] The adaptive approaching law set in the present invention is that when the aircraft is far away from the target, the approaching speed is low. As the aircraft continues to approach the target and the distance between the aircraft and the target continues to decrease, the approaching speed quickly increases to ensure that θ f -q, It can converge to zero, ensuring the interception accuracy and interception angle of the aircraft. In addition, since the above approach law can adaptively adjust the approach speed throughout the whole process, and consider using the hyperbolic tangent function to replace the sign function in the design of the switching function, the chattering is weakened to a certain extent.

[0071] In S4, the adaptive guidance law obtained is expressed as:

[0072]

[0073] Example

[0074] Example 1

[0075] Conduct a simulation experiment of seven aircraft intercepting a single target, including the following steps:

[0076] S1. Establish the relative motion model of single target and multiple aircrafts;

[0077] S2. Obtaining the state equation of the guidance system based on the relative motion model;

[0078] S3, setting the switching surface so that the sight angle error is 0;

[0079] S4, setting an adaptive approaching law and combining it with the switching surface to obtain an adaptive guidance law;

[0080] S5. The aircraft flies using the obtained guidance law.

[0081] In S1, the relative motion model is expressed as:

[0082]

[0083] In S2, the state equation of the guidance system is expressed as:

[0084]

[0085] In S3, set the switching surface s to:

[0086]

[0087] In S4, the adaptive reaching law is set to:

[0088]

[0089] The obtained adaptive guidance law is expressed as:

[0090]

[0091] During the simulation experiment, the parameter values ​​can be set as:

[0092] c=1.14, k=10, ε=0.22, λ=1.07

[0093] The initial target position is The initial track direction is The initial velocity is V T =10m / s, target at 5m / s 2 The acceleration is accelerated.

[0094] The simulation conditions are shown in Table 1.

[0095] Table 1

[0096]

[0097] The simulation results are as follows Figure 2-4 shown.

[0098] in, Figure 2 The flight trajectory simulation results are shown. Figure 3 shows the overload curve simulation results, Figure 4 The interception angle curve simulation results are shown.

[0099] from Figure 2-4 It can be seen that the seven aircraft can accurately intercept the target and meet the interception angle constraint when intercepting the target. They can capture the uniformly accelerated target, and the overload of the seven aircraft during the interception process is relatively small, which can meet the overload constraint.

[0100] The present invention has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, the present invention may be subjected to a variety of substitutions and improvements, all of which fall within the scope of protection of the present invention.

Claims

1. An adaptive sliding mode collaborative guidance method for acceleration target, characterized in that: The following steps are involved: S1. Establish the relative motion model of single target and multiple aircrafts; S2. Obtaining the state equation of the guidance system based on the relative motion model; S3, setting the switching surface so that the sight angle error is 0; S4, setting an adaptive approaching law and combining it with the switching surface to obtain an adaptive guidance law; S5. The aircraft flies using the obtained guidance law.

2. The adaptive sliding mode collaborative guidance method for acceleration target according to claim 1 is characterized in that: In S1, the relative motion model is expressed as: Among them, the subscript i represents different aircraft, r i represents the relative line of sight distance between aircraft i and the target, represents the speed of aircraft i, represents the track angle of aircraft i, q i represents the sight angle between aircraft i and target, V T represents the speed of the target, θ T represents the target’s track angle, represents the acceleration of aircraft i, a T Indicates the acceleration of the target.

3. The adaptive sliding mode collaborative guidance method for acceleration target according to claim 1, characterized in that: In S2, set the system state quantity to Among them, x1 and x2 are system state quantities, q represents the sight angle between the aircraft and the target, is the angular velocity between the aircraft and the target.

4. The adaptive sliding mode collaborative guidance method for acceleration target according to claim 1, characterized in that: The guidance system state equation is expressed as: Among them, u is the control quantity, which represents the component of the aircraft acceleration in the normal direction of the line of sight between the aircraft and the target; ω is the interference quantity, which represents the component of the target acceleration in the normal direction of the line of sight between the aircraft and the target; r represents the relative line of sight distance between the aircraft and the target.

5. The adaptive sliding mode collaborative guidance method for acceleration target according to claim 1, characterized in that: In S3, set the switching surface s to: Among them, θ f represents the desired interception angle, V M is the speed of the aircraft, λ and c are configurable parameters.

6. The adaptive sliding mode collaborative guidance method for acceleration target according to claim 1, characterized in that: In S4, the adaptive reaching law is set to: Among them, k and ε are configurable parameters.

7. The adaptive sliding mode collaborative guidance method for acceleration target according to claim 6, characterized in that: The obtained adaptive guidance law is expressed as:

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