Embedded pneumatic control plane for rocket and control method thereof
Technical Field
The application relates to the technical field of rockets, in particular to an embedded pneumatic control surface for a rocket and a control method thereof.
Background
Currently, Solid rocket engines (Solid propellant rocket engines) are chemical rocket engines that use Solid propellants. Also known as solid propellant rocket engines. The solid propellant is ignited and then burnt in the combustion chamber, and chemical energy is converted into heat energy to produce high-temperature and high-pressure combustion products. The combustion products flow through the nozzle where they expand and accelerate, and the thermal energy is converted to kinetic energy and expelled from the nozzle at high velocity to produce thrust.
In the prior art, a solid rocket engine adopts a pure rotation body layout of a swinging spray pipe, a non-wing steering engine, and a pressure center is always positioned at a position about 30% away from a rocket peak point, the static instability of the solid rocket engine is high, and the control capability of a vector power system is extremely high. The static instability refers to the distance from the aerodynamic center to the gravity center of the rocket, the static stability of the aerodynamic center behind the gravity center is positive, and the rocket is stable; the static stability of the aerodynamic center before the center of gravity is negative and the rocket is unstable.
In the prior art, the static instability degree is reduced by adding the fixed wing, and the requirement of the control capability of a vector power system is reduced, but the fixed wing provides resistance in the rocket flying process and is not beneficial to the rocket flying. In the prior art, a conventional aerodynamic control surface comprises a cross control surface and an X-shaped control surface (namely, the cross control surface rotates by 45 degrees), the control surface provides stability on one hand, and changes the flight attitude of a rocket in a deflection mode as the control surface on the other hand.
Disclosure of Invention
The application aims to provide an embedded pneumatic control surface for a rocket and a control method thereof, and the embedded pneumatic control surface has the characteristics of strong control capability, low bearing weight cost and low flight resistance of the rocket.
To achieve the above object, the present application provides an embedded pneumatic control surface for a rocket, comprising: the control surface is rotationally connected to the tail of the rocket through a rotating shaft, and the servo actuating system is fixedly connected to the tail of the rocket and connected with the control surface;
the servo actuating system comprises a power support rod and a battery power assembly; the power support rod is electrically connected with the battery power assembly; the power support rod is connected between the control surface and the rocket tail outer molded surface, and pushes the control surface to enable the control surface and the rocket tail outer molded surface to be opened at a certain angle.
The distance between the power support rod and the rotating shaft is greater than 1/3 of the length of the control surface and less than 1/2 of the length of the control surface.
The control surface comprises a first control surface, a second control surface, a third control surface and a fourth control surface which are uniformly arranged around the tail of the rocket in a spaced mode;
the power support rod comprises a first power support rod, a second power support rod, a third power support rod and a fourth power support rod which are respectively connected with the first control surface, the second control surface, the third control surface and the fourth control surface.
As described above, the control surface is formed in a circular arc plate shape, and the control surface is provided on the outer peripheral side of the rocket tail outer surface.
As above, the power support rod comprises a fixed cylinder and a telescopic rod, and the telescopic rod is telescopically connected in the fixed cylinder; the end part of the fixed cylinder is fixedly connected with the outer profile of the rocket tail, and the end part of the telescopic rod is hinged with the control surface.
The application also provides a control method of the embedded pneumatic control surface for the rocket, which comprises the following steps:
a relation model for controlling the opening angle of the control surface and the backward displacement of the pressure center is constructed in advance;
determining the minimum pressure center backward movement amount under different flight Mach numbers in the rocket flight process;
obtaining the minimum opening angle theta of the control surface according to the calculated minimum pressure center backward movement and a pre-constructed relation model for controlling the opening angle of the control surface and the pressure center backward movementmin;
Minimum opening angle theta of power support rod driving control surface openingmin。
As above, wherein the method further comprises: calculating the extending length of the power support rod according to the opening angle of the control surface;
the calculation formula of the elongation of the power support rod is as follows:
L=h·tanθ;
wherein L represents the elongation of the power strut; theta represents the opening angle of the control surface; h represents the distance between the power support rod and the rotating shaft when the control surface is not opened in the actuator box.
The method comprises the following steps of (1) calculating the control moment of the rocket under the condition that only one control surface is opened;
the formula for calculating the control moment of the rocket is as follows:
wherein m is
zRepresenting the control moment of the rocket; ρ represents the atmospheric density; v represents the rocket flight speed; s represents a reference area; c
NRepresenting the normal force coefficient; x
cpThe distance between the pressure and the sharp point when the control surface of the rocket is opened is represented; x
GIndicating the distance of the rocket center of gravity from the cusp.
As above, the method of constructing the relation model of the control surface opening angle and the pressure center back shift amount in advance is as follows:
calculating the distance X between the first pressure center of the rocket and the point of the rocket under different flight Mach numbers when the control surface is not openedcp0;
Calculating the distance between the second pressure center of the rocket and the point of the rocket under different flight Mach numbers when the control surface is controlled to be opened at different anglesXcp;
The distance X between the second pressure center and the rocket peak point is obtained according to calculationcpAnd the distance X from the first pressure center to the rocket nose pointcp0Calculating the backward displacement delta X of the pressure center of the rocket under different flight Mach numbers when the control surface is controlled to be opened at different anglescp;
And constructing a relation model of the opening angle of the control surface and the backward movement amount of the pressure center according to the backward movement amount of the pressure center corresponding to the control surface opening at different angles.
As above, the formula for calculating the amount of the pressure center back shift is: Δ Xcp=Xcp-Xcp0(ii) a Wherein, Δ XcpIndicating the amount of heart pressure retrodisplacement.
The beneficial effect that this application realized is as follows:
(1) the control surface surrounds the outer shape surface at the tail part of the rocket in the state that the rocket is not launched, the space is saved, the control starting control surface is controlled to open different angles in the rocket flying process, the control surface is controlled to play a role in controlling the control surface, the angle between the control surface and the outer shape surface at the tail part of the rocket is reduced, and the resistance in the rocket flying process is reduced.
(2) According to the control plane, the control plane is controlled to automatically open a proper angle according to the flight working condition and the control capacity requirement of the rocket in the rocket flight process, so that the rocket is in a static and stable flight state, and control torque is provided for the rocket.
(3) The four-piece control surface can provide a stabilizing effect after being opened at the same angle.
(4) In the process of controlling the rocket to raise head (or lower head), two control surfaces of the existing cross-shaped control surface need to deflect downwards (or upwards) by a certain angle around a rotating shaft to raise the head of the rocket, and in the application, after the single control surface is opened, longitudinal torque is provided to raise the head of the rocket, which is equivalent to the control effect of the traditional control surfaces with multiple control surfaces deflecting.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art according to the drawings.
Fig. 1 is a perspective view of an embedded pneumatic control surface for a rocket according to an embodiment of the present application.
Fig. 2 is a left side view of an embedded pneumatic control surface for a rocket according to an embodiment of the present application.
Fig. 3 is a perspective view of a hidden control surface of an embedded pneumatic control surface for a rocket according to an embodiment of the present application.
Fig. 4 is a front view of an embedded aerodynamic control surface for a rocket according to an embodiment of the present application.
Fig. 5 is a flowchart of a control method of an embedded pneumatic control surface for a rocket according to an embodiment of the present application.
Fig. 6 is a flowchart of a method for constructing a relation model for controlling the opening angle of the control surface and the amount of backward movement of the pressure center in advance according to an embodiment of the present application.
Reference numerals: 1-control surface; 2-a servo actuation system; 3-a rotating shaft; 4-rocket tail outer molded surface; 11-a first control surface; 12-a second control surface; 13-a third control surface; 14-a fourth control surface; 21-a first powered support bar; 22-a second powered support bar; 23-a third power support bar; 24-a fourth powered support bar.
Detailed Description
The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Example one
As shown in fig. 1-4, the application provides an embedded pneumatic control surface for a rocket, which comprises a control surface 1 and a servo actuating system 2, wherein the control surface 1 is rotatably connected to the tail of the rocket through a rotating shaft 3, and the servo actuating system 2 is connected with the control surface 1.
The control surface 1 is in a shape of a circular arc plate, and the control surface 1 is arranged on the periphery side of the rocket tail outer molded surface 4.
The control surface 1 comprises a first control surface 11, a second control surface 12, a third control surface 13 and a fourth control surface 14, the first control surface 11, the second control surface 12, the third control surface 13 and the fourth control surface 14 are uniformly arranged on the circumferential direction of the tail of the rocket at intervals, the first control surface 11 and the third control surface 13 are symmetrically arranged, and the second control surface 12 and the fourth control surface 14 are symmetrically arranged.
The first control surface 11, the second control surface 12, the third control surface 13 and the fourth control surface 14 are arc-shaped plate-shaped structures with the same size and shape. The outer profile of the rocket tail is cylindrical.
The first control surface 11, the second control surface 12, the third control surface 13 and the fourth control surface 14 are respectively and rotatably connected with the tail of the rocket through a first rotating shaft, a second rotating shaft, a third rotating shaft and a fourth rotating shaft.
According to a specific embodiment of the invention, the first rotating shaft, the second rotating shaft, the third rotating shaft and the fourth rotating shaft are all fixedly connected to the tail of the rocket, and the fixed connection mode can be fixed connection through shaft seats or welding. The first rotating shaft, the second rotating shaft, the third rotating shaft and the fourth rotating shaft are arranged at equal intervals along the circumferential direction of the tail of the rocket, the first rotating shaft and the third rotating shaft are symmetrically arranged, and the second rotating shaft and the fourth rotating shaft are symmetrically arranged. The first rotating shaft, the second rotating shaft, the third rotating shaft and the fourth rotating shaft are arranged in a tangent mode with the outer profile of the tail portion of the rocket.
According to an embodiment of the invention, the first control surface 11 is rotatably connected with the first rotating shaft through a first shaft sleeve, the second control surface 12 is rotatably connected with the second rotating shaft through a second shaft sleeve, the third control surface 13 is rotatably connected with the third rotating shaft through a third shaft sleeve, and the fourth control surface 14 is rotatably connected with the fourth rotating shaft through a fourth shaft sleeve.
The servo actuating system 2 comprises a power support rod and a battery power component, the power support rod is electrically connected with the battery power component, and the power support rod is used for pushing the control surface 1 to open a certain angle; the battery power component is used for providing a power source for the power supporting rod.
According to an embodiment of the invention, the distance between the power support rod and the rotating shaft 3 is greater than 1/3 of the length of the control surface 1 and less than 1/2 of the length of the control surface 1. The value range of the distance between the power support rod and the rotating shaft 3 is as follows: l/3 to L/2, wherein L represents the length of the control surface 1. The power support rod is arranged in the value range, so that the pneumatic support rod can control the control surface 1 to be opened at a certain angle under the condition of providing smaller power.
According to a specific embodiment of the present invention, the power support bar is a hydraulic power support bar or a pneumatic power support bar.
According to a specific embodiment of the invention, the power supporting rod comprises a fixed cylinder and a telescopic rod, and the telescopic rod is telescopically connected in the fixed cylinder.
According to an embodiment of the invention, the end of the fixed cylinder is fixedly connected with the rocket tail outer profile 4, and the end of the telescopic rod is hinged with the control surface 1.
According to an embodiment of the invention, the power support rod comprises a first power support rod 21, a second power support rod 22, a third power support rod 23 and a fourth power support rod 24, one end of the first power support rod 21 is connected with the outer profile of the tail part of the rocket, and the other end is connected with the first control surface 11; one end of the second power support rod 22 is connected with the outer profile of the tail part of the rocket, and the other end is connected with the second control surface 12; one end of a third power support rod 23 is connected with the outer profile of the tail part of the rocket, and the other end of the third power support rod is connected with a third control surface 13; one end of the fourth power support rod 24 is connected with the outer profile of the tail of the rocket, and the other end is connected with the fourth control surface 14.
Example two
As shown in fig. 5, the present application provides a control method of an embedded pneumatic control surface for a rocket, the method comprising the steps of:
and step S1, constructing a relation model for controlling the opening angle of the control surface and the backward displacement of the pressure center in advance.
Specifically, as shown in fig. 6, step S1 includes the following sub-steps:
step S110, calculating the distance X between the first pressure center of the rocket and the rocket peak point under different flight Mach numbers when the control surface is not openedcp0。
Specifically, according to the existing CFD (computational fluid dynamics) simulation software, the distance X between the first pressure center of the rocket and the rocket peak point under different flight Mach numbers when the control surface is not opened is calculatedcp0。
The pressure center is the pressure center, and the rocket is subjected to force in one direction under the action of external force to form a force acting on the pressure center.
The flight mach number refers to the ratio of the flight speed of the rocket to the propagation speed of sound in the air.
Wherein, the rocket sharp point refers to the front end tip of the rocket.
Step S120, calculating the distance X between the second pressure center of the rocket and the rocket peak point under different flight Mach numbers when the control surface is controlled to be opened at different anglescp。
Specifically, according to the existing CFD (computational fluid dynamics) simulation software, the distance X between the second pressure center of the rocket and the rocket peak point under different flight Mach numbers is calculated when the control surface is controlled to be opened at different anglescp。
Step S130, obtaining the distance X between the second pressure center and the rocket peak point according to calculationcpAnd the distance X from the first pressure center to the rocket nose pointcp0Calculating the backward displacement delta X of the pressure center of the rocket under different flight Mach numbers when the control surface is controlled to be opened at different anglescp(ii) a Specifically, the formula for calculating the core back displacement is as follows: Δ Xcp=Xcp-Xcp0。
And S140, constructing a relation model of the opening angle of the control surface and the backward movement amount of the pressure center according to the backward movement amount of the pressure center corresponding to the control surface opening at different angles.
The rocket can automatically return to the original equilibrium state after the equilibrium state of the rocket is damaged due to disturbance in the flying process, which is called the stability of the rocket. The rocket deflects by taking the gravity center of the rocket as an axis under the action of external force, and if the gravity center is in front of the pressure center, a certain distance exists between the pressure center and the gravity center, so that the rocket is yawed by the generated moment.
The requirement for static stability of the rocket is that the center of pressure of the rocket is located behind the center of gravity, i.e. Xcp-XG>0; wherein XcpThe distance between the pressure center of the rocket and the point of the rocket is represented; xGIndicating the distance of the rocket's center of gravity from the rocket's cusp.
The rocket is in a static and stable flight state and requires delta Xcp>XG-Xcp0;ΔXcpAnd the control surface is opened, and the pressure center is moved backwards. In other words, the rocket is in a static and stable flight state, the backward displacement of the pressure center after the control surface is opened is required to be greater than the distance between the gravity center of the rocket and the point of the rocket minus the distance between the pressure center and the point of the rocket when the control surface is not opened, wherein in the process of the rocket flight, the fuel of the rocket is gradually reduced, and the distance between the gravity center of the rocket and the point of the rocket gradually moves towards the direction of the point of the rocket along with the increase of the flight time of the rocket; distance X of second pressure center from rocket cuspcpIs related to the rocket's flight mach number.
And step S2, determining the minimum pressure center backward movement amount under different flight Mach numbers in the rocket flight process.
Specifically, the minimum pressure center backward movement amount of the rocket under different flight Mach numbers is determined according to the flight trajectory of the rocket.
Specifically, according to different flight Mach numbers and the distance X between the second pressure center and the rocket cuspcpObtaining the distance X between the second pressure center and the rocket peak point by a relation model of the flight Mach number of the rocketcp(ii) a According to the calculation formula delta X of the core back-moving amountcp=Xcp-Xcp0(ii) a And calculating the minimum pressure center backward movement amount of the rocket under different flight Mach numbers.
Wherein the second pressure center is at a distance X from the rocket cuspcpThe relation model of the rocket with the flight Mach number is constructed in advance.
Step S3, according to the calculated minimum pressure center backward shift amount and the pre-constructed control surface opening angle and pressure center backward shift amountObtaining a minimum opening angle theta of the control surfacemin。
Step S4, the power support rod drives and controls the control surface to open the minimum opening angle thetamin。
Specifically, the first power support rod 21, the second power support rod 22, the third power support rod 23 and the fourth power support rod 24 respectively drive the first control surface 11, the second control surface 12, the third control surface 13 and the fourth control surface 14 to open by thetaminAnd (4) degree.
And step S5, calculating the extending length of the power support rod according to the opening angle of the control surface.
When the control plane is not opened, the power support rod is positioned in the actuator box and is vertical to the outer profile of the tail of the rocket.
The calculation formula of the elongation of the power support rod is as follows:
L=h·tanθ;
wherein L represents the elongation of the power strut; theta represents the opening angle of the control surface; h represents the distance between the power support rod and the rotating shaft when the control surface is not opened in the actuator box.
And step S6, calculating the control moment of the rocket under the condition that only one control surface is opened.
The formula for calculating the control moment of the rocket is as follows:
wherein m iszRepresenting the control moment of the rocket; ρ represents the atmospheric density; v represents the rocket flight speed; s represents a reference area; cNRepresenting the normal force coefficient; xcpThe distance between the pressure and the sharp point when the control surface of the rocket is opened is represented; xGIndicating the distance of the rocket center of gravity from the cusp.
According to the existing CFD (computer fluid dynamics) simulation software, normal force coefficients C of different flight Mach numbers, different common angles and different opening angles of a single-chip control surface are calculatedNAnd a second press center position Xcp。
According to a specific embodiment of the invention, in the process of statically stable flight of the rocket, the four control surfaces are opened at the same angle along with the flight working condition to keep the stable flight of the rocket; when turning is needed, the rocket controls three control surfaces to be closed, one control surface is opened for a certain angle to provide turning moment of the rocket, and the rocket turns under the action of the turning moment; when the rocket does not need to turn again, the rocket controls the four control planes to open the same angle again to keep the stable flight of the rocket.
The beneficial effect that this application realized is as follows:
(1) the control surface surrounds the outer shape surface at the tail part of the rocket in the state that the rocket is not launched, the space is saved, the control starting control surface is controlled to open different angles in the rocket flying process, the control surface is controlled to play a role in controlling the control surface, the angle between the control surface and the outer shape surface at the tail part of the rocket is reduced, and the resistance in the rocket flying process is reduced.
(2) According to the control plane, the control plane is controlled to automatically open a proper angle according to the flight working condition and the control capacity requirement of the rocket in the rocket flight process, so that the rocket is in a static and stable flight state, and control torque is provided for the rocket.
(3) The four-piece control surface can provide a stabilizing effect after being opened at the same angle.
(4) In the process of controlling the rocket to raise head (or lower head), two control surfaces of the existing cross-shaped control surface need to deflect downwards (or upwards) by a certain angle around a rotating shaft to raise the head of the rocket, and in the application, after the single control surface is opened, longitudinal torque is provided to raise the head of the rocket, which is equivalent to the control effect of the traditional control surfaces with multiple control surfaces deflecting.
While one embodiment of the present invention has been described in detail, the description is only a preferred embodiment of the present invention and should not be taken as limiting the scope of the invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.