CN105759830B - Lift aircraft high-dynamic downward-pressing section guidance method - Google Patents

Abstract

The invention discloses a lift aircraft high-dynamic downward-pressing section guidance method. The steps include: calculating downward-pressing section guidance force, and calculating an downward-pressing section instruction according to the guidance force; and by tracking the downward-pressing section instruction, controlling flight of the lift aircraft in a downward-pressing section process. The lift aircraft high-dynamic downward-pressing section guidance method realizes high-speed downward-pressing section guidance of the aircraft, and solves the problem of strict constraints on downward-pressing section termination height, angle of inclination, lateral position and the like.

Description

High-dynamic pressing section guidance method for lift aircraft

Technical Field

The invention relates to the field of spaceflight, in particular to a high-dynamic pressing section guidance method for a lift type aircraft.

Background

The flight process of the lifting type aircraft generally comprises a reentry initial section, a gliding section, a pushing section and other flight sections, the aircraft needs to fly the pushing section under a high dynamic condition after gliding is finished, the aircraft needs to bear large overload and dynamic pressure, the overload and dynamic pressure are strictly limited due to the limitation of systems such as an aircraft structure, the lifting type aircraft in the high-speed aircraft is different from an axisymmetric aircraft, the lifting type aircraft needs to turn over for 180 degrees, the pushing section flight process can be realized by turning over at a large attack angle, and the corresponding height, lateral position, inclination angle, flight range and other constraint limits are also met at the pushing section terminal.

The existing guidance method is mainly used for the flight of the push-down section of the axisymmetric aircraft, and is not suitable for the problem of the push-down section of the lift aircraft under the high dynamic condition because the terminal parameters are not strictly controlled.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a high-dynamic pressing section guidance method of a lift aircraft, which realizes high-speed turning-over pressing guidance of the lift aircraft and solves the problems that the turning-over of the aircraft is difficult under the high-dynamic condition and the terminal height, the inclination angle, the lateral position and the like of the pressing section are strictly restricted.

The invention provides a high-dynamic downward-pressing section guidance method of a lift type aircraft, which is improved in that the method comprises the following steps:

(1) calculating the guidance force of the pressing section, wherein the guidance force comprises a normal force, a normal force instruction and a lateral force;

(2) calculating a pressing section command according to the guidance force, wherein the pressing section command comprises a roll angle command and an attack angle command;

(3) and the flight of the lifting type aircraft in the process of the pressing section is controlled by tracking the instruction of the pressing section.

Preferably, the normal force is calculated by:

F_yc1＝N_ycx0·m·g₀，F_yc2＝-[K_h1(h-H_cx)+K_hd1(sin(Θ)-sin(Θ_cx))V_d]wherein:

H_cxbeing height instructions, Θ_cxFor the inclination angle command, N_ycx0Normal overload command in nominal state, m aircraft mass, g₀Is gravity, N_ycx0>0，-F_N1≤F_yc2≤F_N1，F_N1>0.0, the guidance limiting force; h is the flying height; theta is the local ballistic inclination angle; v_dIs the instantaneous speed of the aircraft; k_h1Proportional link coefficient, K, for high PD control_hd1Differential link coefficients for height PD control;

the normal force command calculation method comprises the following steps: f_ycx＝F_yc1×K_sgnl+F_yc2Wherein, K is_sgnlThe turning-over mark is a turning-over mark of the lift-type aircraft, and the value is-1 if the aircraft turns over, and the value is 1 if the aircraft does not turn over.

Preferably, the calculation method of the lateral force comprises the following steps:

wherein,as a lateral position command, Z^gAs regards the lateral position of the aircraft,in order to provide a lateral velocity command,as aircraft lateral velocity, K_z、K_zdAs lateral guidance parameter, K_zProportional link coefficient, K, for lateral position PD control_zdThe differential element coefficient is controlled by the lateral position PD.

Preferably, the roll angle command is calculated by:

the problem of continuity of angles is to be considered.

Preferably, the calculation method of the angle of attack instruction is as follows:

α_cx＝(C_n-c₀)/c₁，wherein, c₀、c₁Designing parameters for guidance, and generally taking constant values; q is dynamic pressure, S_mIs the aircraft characteristic area.

The invention mainly aims at the high dynamic pressing section flight of the lifting type aircraft, adopts a turning and pressing mode, accurately controls parameters such as height, inclination angle, lateral position and the like, and meets the terminal constraint requirement of the pressing section.

Based on the PD feedback control principle, longitudinal constraint conditions, namely multiple constraint conditions such as height, inclination angle and the like, are ingeniously converted into single visual normal force requirements through normal force calculation, and normal overload constraint is considered at the same time; converting the lateral position and the lateral speed into the lateral force requirement through the calculation of the lateral force; the normal force and the lateral force are combined with the aerodynamic characteristics of the aircraft, the inclination angle instruction and the attack angle instruction are derived, the guidance instruction can be conveniently tracked by the attitude control system, and the accurate flight control of the lift type aircraft in the downward pressing section in the high dynamic environment is realized.

Drawings

Fig. 1 is a flowchart of a lift type aircraft high-dynamic hold-down section guidance method according to an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings by way of examples of preferred embodiments. It should be noted, however, that the numerous details set forth in the description are merely for the purpose of providing the reader with a thorough understanding of one or more aspects of the present invention, which may be practiced without these specific details.

FIG. 1 shows a flow chart of a lift type aircraft high dynamic depressing section guidance method according to an embodiment of the invention. As shown in FIG. 1, the lift type aircraft high dynamic depressing section guidance method comprises the following steps.

Assuming the flight longitudinal track of the push-down section as an altitude instruction H_cxTilt angle command theta_cxNominal state normal overload command N_ycxLateral position commandLateral velocity command

(1) And calculating the guidance force of the pressing section, which comprises the normal force, the normal force command and the lateral force.

The normal force calculation method comprises the following steps:

F_yc1＝N_ycx0·m·g₀，F_yc2＝-[K_h1(h-H_cx)+K_hd1(sin(Θ)-sin(Θ_cx))V_d]_；

wherein: f_yc1Normal force required for nominal condition, N_ycx0For nominal state normal overload command, N_ycx0>0, m is the aircraft mass, g₀Is gravity, F_yc2Normal force required for guidance, K_h1，K_hd1For longitudinal guidance parameters, H is the flight altitude, H_cxFor altitude command, Θ is the local ballistic dip angle, Θ_cxFor tilt angle commands, V_dIs the instantaneous speed of the aircraft, -F_N1≤F_yc2≤F_N1，F_N1>And 0.0 is the guidance limiting force.

The normal force command calculation method comprises the following steps:

F_ycx＝F_yc1×K_sgnl+F_yc2(ii) a Wherein, K_sgnlThe turning sign is a lifting force type aircraft turning sign, if the aircraft turns over, the value is-1, and if the aircraft does not turn over, the value is 1.

The calculation method of the lateral force comprises the following steps:

wherein,as a lateral position command, Z^gAs regards the lateral position of the aircraft,in order to provide a lateral velocity command,as aircraft lateral velocity, K_z、K_zdIs a lateral guidance parameter.

(2) And calculating a roll angle command and an attack angle command according to the normal force and the lateral force required by the pressing section.

The calculation method of the roll angle command comprises the following steps:

to ensure continuity of roll angle, the roll angle command can be extended to infinity.

The calculation method of the attack angle instruction comprises the following steps:

α_cx＝(C_n-c₀)/c₁，wherein, the normal force coefficient of the lift type aircraft can be expressed as C_n＝c₁α_cx+c₀Form (b) of₀、c₁The aerodynamic correlation coefficient can be obtained by fitting the aerodynamic characteristics of the aircraft, and generally takes a constant value, q is dynamic pressure, and S is_mIs the aircraft characteristic area.

(3) In practical application, the attitude control system compares the roll angle instruction and the attack angle instruction with the actual roll angle and attack angle calculated by the navigation system, outputs an aircraft control surface deflection instruction by combining with a corresponding control rule, completes tracking of a guidance instruction, and realizes control of the lift type aircraft in the flight process of a depressing stage.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.

Claims (4)

1. A lift type aircraft high-dynamic downward-pressing section guidance method is characterized by comprising the following steps:

(1) calculating the guidance force of the pressing section, wherein the guidance force comprises a normal force, a normal force instruction and a lateral force;

(2) calculating a pressing section command according to the guidance force, wherein the pressing section command comprises a roll angle command and an attack angle command;

(3) controlling the flight of the lifting type aircraft in the process of the pressing section by tracking the pressing section instruction;

the method for calculating the normal force comprises the following steps:

F_yc1＝N_ycx0·m·g₀，F_yc2＝-[K_h1(h-H_cx)+K_hd1(sin(Θ)-sin(Θ_cx))V_d]，

wherein: h_cxBeing height instructions, Θ_cxFor the inclination angle command, N_ycx0Normal overload command in nominal state, m aircraft mass, g₀Is gravity, N_ycx0>0，-F_N1≤F_yc2≤F_N1，F_N1>0.0, the guidance limiting force; h is the flying height; theta is the local ballistic inclination angle; v_dIs the instantaneous speed of the aircraft; k_h1Proportional link coefficient, K, for high PD control_hd1Differential link coefficients for height PD control;

the normal force command calculation method comprises the following steps: f_ycx＝F_yc1×K_sgnl+F_yc2Wherein, K is_sgnlThe turning-over mark is a turning-over mark of the lift-type aircraft, and the value is-1 if the aircraft turns over, and the value is 1 if the aircraft does not turn over.

2. The push down segment guidance method of claim 1 wherein the lateral force is calculated by:

wherein,as a lateral position command, Z^gAs regards the lateral position of the aircraft,in order to provide a lateral velocity command,as aircraft lateral velocity, K_z、K_zdIs a lateral guidance parameter.

3. The pushdown segment guidance method according to any one of claims 1-2, wherein the roll angle command is calculated by:

${\mathrm{\γ}}_{cx}={\mathrm{tg}}^{-1}\left(\frac{F_{zcx}}{F_{ycx}}\right),{\mathrm{\γ}}_{cx}\∈(-\mathrm{\π},\mathrm{\π}\].$

4. the push-down segment guidance method according to claim 3, wherein the attack angle command is calculated by:

α_cx＝(C_n-c₀)/c₁，wherein, c₀、c₁Designing parameters for guidance, and generally taking constant values; q is dynamic pressure, S_mIs the aircraft characteristic area.