Adaptive sliding mode cooperative guidance method for acceleration target

Abstract

The application discloses an adaptive sliding mode cooperative guidance method for accelerating targets, and comprises the following steps: establishing a relative motion model of a single target and multiple aircrafts; obtaining a state equation of a guidance system based on the relative motion model; setting a switching surface so that a line-of-sight angle error is 0; setting an adaptive approach law, and obtaining an adaptive guidance law in combination with the switching surface; and flying the aircrafts by using the obtained guidance law. The adaptive sliding mode cooperative guidance method for accelerating targets can realize that multiple aircrafts intercept the same target at different desired angles, and the aircrafts are stable during the interception process and have anti-disturbance capability.

Description

TECHNICAL FIELD

[0001] The application relates to an adaptive sliding mode cooperative guidance method for accelerating targets and belongs to the technical field of flight control. BACKGROUND

[0002] For intercepting high-maneuvering high-value targets, a multi-aircraft cooperative interception mode is usually adopted in engineering to improve the target capture probability.

[0003] In order to improve the damage effect and interception accuracy of the multi-aircraft on the target, the multi-aircraft is required to meet the angle constraint and overload constraint at the interception end simultaneously, and has a certain anti-interference ability during the interception process. However, the existing guidance method is difficult to meet the above requirements simultaneously.

[0004] Due to the above reasons, it is necessary to conduct in-depth research on the existing cooperative guidance method to solve the above problems. SUMMARY

[0005] In order to overcome the above problems, in-depth research is conducted, and an adaptive sliding mode cooperative guidance method for accelerating targets is proposed, which comprises the following steps:

[0006] S1, a relative motion model of a single target and a multi-aircraft is established;

[0007] S2, a state equation of a guidance system is obtained based on the relative motion model;

[0008] S3, a switching surface is set so that the line-of-sight angle error is 0;

[0009] S4, an adaptive approach law is set, and an adaptive guidance law is obtained in combination with the switching surface;

[0010] S5, the aircraft adopts the obtained guidance law to fly.

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

[0012]

[0013] Wherein, the subscript i represents different aircrafts, r i represents the relative line-of-sight distance of the aircraft i and the target, represents the speed of the aircraft i, represents the track angle of the aircraft i, q i represents the line-of-sight angle of the aircraft i and the target, V T represents the speed of the target, theta T represents the track angle of the target, represents the acceleration of the aircraft i, a T represents the acceleration of the target.

[0014] In one preferred embodiment, in S2, the system state quantity is set as x1=-q,

[0015] wherein x1, x2 are system state quantities, q represents the line-of-sight angle of the aircraft and the target, is the line-of-sight angle rate of the aircraft and the target.

[0016] In one preferred embodiment, the guidance system state equation is represented as:

[0017]

[0018] wherein u is a control quantity, representing the component of the aircraft acceleration in the normal direction of the line-of-sight of the aircraft and the target; ω is a disturbance quantity, representing the component of the target acceleration in the normal direction of the line-of-sight of the aircraft and the target; r represents the relative line-of-sight distance of the aircraft and the target.

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

[0020]

[0021] wherein θ f represents the desired intercept angle, V M is the speed of the aircraft, λ, c are settable parameters.

[0022] In one preferred embodiment, in S4, the adaptive approach law is set as:

[0023]

[0024] wherein k, ε are settable parameters.

[0025] In one preferred embodiment, the obtained adaptive guidance law is represented as:

[0026]

[0027] The present application has the beneficial effects including:

[0028] (1) Multiple aircrafts can achieve interception of the same target at different desired angles;

[0029] (2) The aircrafts fly at a small overload during the interception process, so that the aircrafts fly smoothly when approaching the target;

[0030] (3) It has certain anti-disturbance ability, reduces the influence of internal and external disturbances on the interception accuracy, and weakens the chattering in the flight process. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Fig. 1 shows a flow chart of an adaptive sliding mode cooperative guidance method for accelerating targets according to a preferred embodiment of the present application;

[0032] Figure 2 Fig. 4 shows a simulation result of flight trajectory of a vehicle in an embodiment;

[0033] Figure 3 Fig. 5 shows a simulation result of overload curve of a vehicle in an embodiment;

[0034] Figure 4 Fig. 6 shows a simulation result of intercept angle curve of a vehicle in an embodiment. DETAILED DESCRIPTION

[0035] The present application will be further described by the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present application will become more apparent.

[0036] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Unless specifically stated otherwise, the drawings are not drawn to scale and the disclosure is not limited to the specific embodiments illustrated in the drawings.

[0037] The adaptive sliding mode cooperative guidance method for accelerating targets according to the present application comprises the following steps as shown in Fig. 1: Figure 1

[0038] S1, establishing a relative motion model of a single target and multiple vehicles;

[0039] S2, obtaining a state equation of a guidance system based on the relative motion model;

[0040] S3, setting a switching surface so that a line-of-sight angle error is 0;

[0041] S4, setting an adaptive approaching law to obtain an adaptive guidance law in combination with the switching surface;

[0042] S5, the vehicles fly by using the obtained guidance law.

[0043] In the present application, by setting a switching surface and an adaptive approaching law, the guidance law is obtained based on a sliding mode variable structure control method, which can realize that multiple vehicles intercept targets at different desired angles, and control the vehicles at a small overload, thereby providing a good working environment for a measuring device carried on the vehicles and reducing the influence of external disturbances such as measurement error, change of air dynamics, change of weather conditions, and the like on the intercept accuracy.

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

[0045] ​

[0046] wherein subscript i represents different aircraft, r i represents the relative line-of-sight distance of aircraft i to the target, represents the velocity of aircraft i, represents the track angle of aircraft i, q i represents the line-of-sight angle of aircraft i to the target, V T represents the velocity of the target, θ T represents the track angle of the target, represents the acceleration of aircraft i, a T represents the acceleration of the target, and the superscript · represents first-order derivation.

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

[0048]

[0049] Let:

[0050]

[0051] Substituting the above formula, we obtain:

[0052]

[0053] wherein u r and ω r are the components of the aircraft acceleration and the target acceleration in the line-of-sight direction of the aircraft-target, respectively; u q and ω q are the components of the aircraft acceleration and the target acceleration in the normal direction of the line-of-sight direction of the aircraft-target, respectively, and the superscript ·· represents second-order derivation.

[0054] In actual guidance, the aircraft is generally not controlled in the line-of-sight direction of the aircraft-target, and only the relative velocity of the aircraft and the target in this direction needs to be less than 0, and only the component u r of the aircraft acceleration in the normal direction of the line-of-sight direction of the aircraft-target needs to be controlled to achieve the guidance, and thus we have:

[0055]

[0056] wherein u is the control quantity, and ω is the interference quantity.

[0057] According to a preferred embodiment of the present application, the system state quantity is set as x1=-q,

[0058] wherein x1, x2 are system state quantities, and q represents the line-of-sight angle of the aircraft to the target. The angle rate of line of sight between the aircraft and the target.

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

[0060]

[0061] Wherein, u is a control quantity, indicating the component of the aircraft acceleration in the normal direction of the line of sight between the aircraft and the target; ω is an interference quantity, indicating the component of the target acceleration in the normal direction of the line of sight between the aircraft and the target; r indicates the relative distance of the line of sight between the aircraft and the target.

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

[0063]

[0064] Wherein, θ f Indicates the desired intercept angle, V M is the speed of the aircraft, λ and c are settable parameters.

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

[0066] Further, according to the first item after setting the switching surface equation, when the aircraft flies towards the target from far to near, The value will change from small to large, which means that the zero rate of the first item will also change from slow to fast, and the meaning of the first item is just the intercept angle constraint, so the above switching surface can realize that when the aircraft approaches the target, the intercept angle quickly approaches the desired attack angle, which has self-adaptivity.

[0067] In S4, the adaptive approaching law is set as:

[0068]

[0069] Wherein, k and ε are settable parameters.

[0070] The adaptive approaching law set in the application has a small approaching speed when the aircraft is far away from the target, and the approaching speed quickly becomes fast when the aircraft continuously approaches the target and the distance between the aircraft and the target continuously decreases, so that θ f -q, The convergence to zero guarantees the interception accuracy and interception angle of the aircraft. In addition, the above-mentioned approaching law can adaptively adjust the approaching speed throughout the process, and the hyperbolic tangent function is used to replace the sign function in the design of the switching function, so that the chattering is weakened to a certain extent.

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

[0072]

[0073] Embodiment

[0074] Embodiment 1

[0075] Seven aircraft-to-single-target interception simulation experiments are carried out, including the following steps:

[0076] S1, a relative motion model of a single target and multiple aircrafts is established;

[0077] S2, a state equation of a guidance system is obtained based on the relative motion model;

[0078] S3, a switching surface is set so that the line-of-sight angle error is 0;

[0079] S4, an adaptive approaching law is set, and an adaptive guidance law is obtained in combination with the switching surface;

[0080] S5, the aircraft uses the obtained guidance law to fly.

[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, the switching surface s is set as:

[0086]

[0087] In S4, the adaptive approaching law is set as:

[0088]

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

[0090]

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

[0092] c=1.14, k=10, ε=0.22, λ=1.07

[0093] The initial position of the target is The initial trajectory direction is The initial velocity is V T =10m / s, the target moves at 5m / s 2 It accelerates its motion with acceleration.

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

[0095] Table 1

[0096]

[0097] Simulation results are as follows Figures 2-4 As shown.

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

[0099] from Figures 2-4 As can be seen, all seven aircraft were able to accurately intercept the target, and the interception angle constraints were met when intercepting the target. They were able to surround and capture uniformly accelerating targets, and the overload of the seven aircraft during the interception process was relatively small, which met the overload constraints.

[0100] The present invention has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present invention based on these embodiments, all of which fall within the scope of protection of the present invention.

Claims

1. An adaptive sliding mode cooperative guidance method for accelerating targets, characterized in that, Includes the following steps: S1. Establish a relative motion model for a single target and multiple aircraft; S2. Obtain the state equation of the guidance system based on the relative motion model; S3. Set the switching surface so that the viewing angle error is 0; S4. Set an adaptive approach law and combine it with the switching surface to obtain an adaptive guidance law; S5. The aircraft uses the acquired guidance law to fly. In S3, the switching surface s is set as follows: Where, θ f V represents the desired interception angle. M Let be the speed of the aircraft, λ and c be configurable parameters, r represent the relative line-of-sight distance between the aircraft and the target, and q represent the line-of-sight angle between the aircraft and the target. The line-of-sight angular rate between the aircraft and the target; In S4, the adaptive reaching law is set as follows: Where k and ε are settable parameters; The obtained adaptive guidance law is expressed as: u is a control variable, representing the component of the aircraft's acceleration in the normal direction of the line of sight between the aircraft and the target.

2. The adaptive sliding mode cooperative guidance method for acceleration targets according to claim 1, characterized in that, In S1, the relative motion model is represented as: Where the subscript i represents different aircraft, r i This indicates the relative line-of-sight distance between aircraft i and the target. Indicates the speed of aircraft i. q represents the trajectory angle of aircraft i. i V represents the line-of-sight angle between aircraft i and the target. T θ represents the velocity of the target. T Indicates the target's trajectory angle. a represents the acceleration of aircraft i. T This indicates the target's acceleration.

3. The adaptive sliding mode cooperative guidance method for acceleration targets according to claim 1, characterized in that, In S2, the system state variable is set to x1 = -q. Where x1 and x2 are system state variables.

4. The adaptive sliding mode cooperative guidance method for acceleration targets according to claim 3, characterized in that, The state equation of the guidance system is expressed as: Where ω is the interference quantity, representing the component of the target acceleration in the normal direction of the line of sight between the aircraft and the target.

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