CN110940232A

CN110940232A - Guidance method for BTT-90-degree guidance law missile

Info

Publication number: CN110940232A
Application number: CN201911371633.2A
Authority: CN
Inventors: 闫斌斌; 刘双喜; 戴沛; 任子君; 符文星
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2020-03-31

Abstract

The invention provides a guidance method for a BTT-90-degree guidance law missile, which comprises the steps of firstly calculating a missile normal overload instruction n_ycAnd a lateral overload command n_zcSecondly, calculating missile overload command n_cAnd roll angle command gamma_cAnd then designing a hysteresis form and width according to the obtained roll angle instruction, and carrying out nonlinear processing on the roll angle instruction: when the roll angle command is saturated, the amplitude limiting is carried out while keeping the command unchanged, and when the roll angle command is not saturated, the roll angle command is consistent with the roll angle command in the step 2, and the final roll angle command gamma 'is obtained'_c. The invention is realized by aiming at a roll angle instruction arctan (n)_zc/n_yc) A nonlinear link is designed, and the form and the width of a hysteresis loop are reasonably set, so that the phenomenon of violent change of a BTT-90-degree guidance instruction is avoided. The method does not need to measure additional physical quantity, is simple in calculation and is easy to implement.

Description

Guidance method for BTT-90-degree guidance law missile

Technical Field

The invention belongs to the field of missile guidance control, and particularly relates to a guidance algorithm for a BTT-90-degree guidance law missile.

Background

The Bank-To-Turn (BTT) guidance control technology is characterized in that the Bank-To-Turn guidance control technology can be realized by the inclination of a projectile bodyTurning or maneuvering, namely the missile quickly turns the maximum lifting surface to the direction required by maneuvering through the rolling channel on the premise of ensuring that the sideslip angle of the missile body is approximately zero, and meanwhile, the missile is controlled to generate required acceleration in the maximum lifting surface through the pitching channel, so that the quick maneuvering of the missile is realized. The advantages of the method are mainly reflected in the aspects of pneumatic efficiency, maneuvering performance, control performance, stability performance, hit precision and the like. Depending on the angular range over which the missile may roll, BTT guidance control techniques are broadly divided into: BTT-45 degrees, BTT-90 degrees and BTT-180 degrees. The BTT-90 degrees has the capability of generating positive and negative attack angles or positive and negative lift forces, and controls the missile to actively make around a longitudinal axis, so that the synthetic normal overload of the missile falls in a maximum lift force plane. In the rectangular coordinate system, the generation principle of the BTT-90 rolling angle instruction is shown in FIG. 1. The roll angle information can be according to the normal and lateral plane overload instruction n output by the flight control system_yc、n_zcOr according to the angular rate of the normal, lateral plane of the view given by the seeker

And (4) extracting.

The overload command and the roll angle command are respectively

γ_c＝arctan(n_zc/n_yc)

During the actual flight of the missile, the flight conditions are uncertain, and n is the influence of various interferences_ycAnd n_zcThe guidance instruction is changed violently, so that the stability and the hit precision of the missile are seriously influenced, and the missile is out of control. Therefore, the optimization of the guidance law algorithm adopting the BTT-90-degree missile is particularly important.

Disclosure of Invention

The invention aims to solve the problems of difficult control, low stability and the like of a guided missile in the implementation process of the conventional BTT-90-degree guidance method, and provides a guidance method for a BTT-90-degree guidance law guided missile, which can simultaneously improve the stability problem and the hit precision problem in the BTT-90-degree guidance control process.

The technical scheme of the invention is as follows:

the guidance method for the BTT-90-degree guidance law missile is characterized by comprising the following steps: the method comprises the following steps:

step 1: calculating missile normal overload instruction n_ycAnd a lateral overload command n_zc：

Wherein K_yFor normal overload command guidance ratio, K_zIn order to command the pilot ratio for a lateral overload,

for the angular rate of the normal line of sight,

the angular velocity of a lateral sight line, V the flight velocity of the missile and g the gravity coefficient of the earth;

step 2: calculating a missile overload instruction n according to the calculation result in the step 1_cAnd roll angle command gamma_cAre respectively as

γ_c＝arctan(n_zc/n_yc)

Wherein (| γ)_c|≤90°)；

And step 3: designing a hysteresis form and width according to the rolling angle instruction obtained in the step 2, and carrying out nonlinear processing on the rolling angle instruction: when the roll angle command is saturated, the amplitude limiting is carried out while keeping the command unchanged, and when the roll angle command is not saturated, the roll angle command is consistent with the roll angle command in the step 2, and the final roll angle command gamma 'is obtained'_c

p (k) is expressed by

Wherein gamma'_cRepresenting a roll angle command after nonlinear processing, [ -M, M]Represents the hysteresis region [ -b, b [ -b]Indicating the hysteresis width, and k indicates that the current time is the kth sampling time.

Advantageous effects

The invention is realized by aiming at a roll angle instruction arctan (n)_zc/n_yc) A nonlinear link is designed, and the form and the width of a hysteresis loop are reasonably set, so that the phenomenon of violent change of a BTT-90-degree guidance instruction is avoided. The method does not need to measure additional physical quantity, is simple in calculation and is easy to implement.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 shows a block diagram of the BTT guidance law missile guidance instruction calculation.

FIG. 2 shows a flow chart of a guidance algorithm for a BTT-90 ° guidance law missile.

Fig. 3 shows a schematic view of a hysteresis loop according to the present invention.

Detailed Description

The following detailed description of embodiments of the invention is intended to be illustrative, and not to be construed as limiting the invention.

Referring to fig. 2, the invention relates to a guidance algorithm for a BTT-90 ° guidance law missile, which comprises the following steps:

1. calculating missile normal overload instruction n_ycAnd a lateral overload command n_zc：

Wherein K_yFor normal overload command guidance ratio, K_zThe values of the lateral overload instruction guide ratios are all between 3 and 5.

For the angular rate of the normal line of sight,

they are measured directly by the seeker for lateral line-of-sight angular velocity. V is the missile flight speed, and g is the coefficient of gravity of the earth.

2. Calculating a missile control instruction under a BTT-90-degree guidance law:

according to the calculation result in the step 1, the missile control instruction calculation method comprises the following steps:

wherein n is_cIndicating missile overload command, gamma_cIndicating the missile roll angle command (| gamma)_c|≤90°)。

3. Calculating a control instruction under a guidance algorithm aiming at a BTT-90-degree guidance law missile:

and (3) designing a hysteresis form and width according to the roll angle instruction calculated in the step (2), and carrying out nonlinear processing on the roll angle instruction. When the rolling angle instruction is saturated, keeping the instruction unchanged, and carrying out amplitude limiting; when the roll angle command is not saturated, the roll angle command is consistent with the roll angle command in the step 2. The mathematical description of this hysteresis in said step 3 is

p (k) is expressed by

Wherein gamma'_cRepresenting a roll angle command after nonlinear processing, [ -M, M]Represents the hysteresis region [ -b, b [ -b]Represents the hysteresis width, k represents the current time being the kth sampling time, gamma_c(k) Indicating the roll angle command input value at the current time.

p(k)，γ_c(k)，γ′_cThe calculation logic of (a) is: gamma is calculated by the step 2_c(k) In combination with gamma_c(k) Judging the calculated value to obtain p (k); and step 3, correcting gamma under the influence of hysteresis_c(k) Obtaining a roll angle command gamma 'after nonlinear processing'_c。

In this example, M ═ b ═ 85, in this case γ'_cThe specific expression of (A) is as follows:

by the aid of the algorithm, the phenomenon that a BTT-90-degree guidance instruction changes violently can be avoided, a good foundation is provided for stable control of the posture of the projectile body, extra physical quantities do not need to be measured, and the algorithm is simple in calculation and easy to achieve.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.

Claims

1. A guidance method for a BTT-90-degree guidance law missile is characterized by comprising the following steps: the method comprises the following steps:

for the angular rate of the normal line of sight,

step 2: calculating a missile overload instruction n according to the calculation result in the step 1_cAnd the roll angle command γ c are respectively

γ_c＝arctan(n_zc/n_yc)

Wherein (| γ)_c|≤90°)；

And step 3: designing a hysteresis form and width according to the rolling angle instruction obtained in the step 2, and carrying out nonlinear processing on the rolling angle instruction: when the roll angle instruction is saturated, the roll angle instruction is kept unchanged, amplitude limiting is carried out, and when the roll angle instruction is not saturated, the roll angle instruction is kept as same as the roll angle instruction in the step 2To obtain a final roll angle command γ'_c

p (k) is expressed by

2. A guidance method for a BTT-90 ° guidance law missile according to claim 1, characterized in that: normal overload command guide ratio K_yAnd a lateral overload command-to-pilot ratio K_zThe value range is between 3 and 5.

3. A guidance method for a BTT-90 ° guidance law missile according to claim 1, characterized in that: the hysteresis area and the hysteresis width are M-b-85.