A launch vehicle plus stage joint orbit design method

Abstract

The launch vehicle plus upper stage joint orbit design method comprises the following steps: step 1, taking the launch vehicle as a base stage and the upper stage as a terminal stage, a three-degree-of-freedom joint trajectory optimization model is established; step 2, according to the target task characteristics, the joint design orbit section is determined; the joint design orbit section comprises the upper stage working times and the transfer orbit type; step 3, the upper stage first working starting point is determined, and the joint optimization is completed; after the transfer orbit is determined, the launch vehicle base stage and the upper stage first working section are subjected to joint orbit optimization, and the upper stage first working starting point is determined. The launch vehicle plus upper stage joint orbit design method can greatly improve the carrying capacity of the combination of the launch vehicle base stage and the upper stage by jointly optimizing the trajectories of the launch vehicle base stage and the upper stage and determining the upper stage first working starting point, and has high application value in engineering.

Description

TECHNICAL FIELD

[0001] The present application relates to a launch vehicle plus upper stage joint orbit design method, which is suitable for launch vehicle trajectory design and belongs to the field of launch vehicle trajectory design. BACKGROUND

[0002] In recent years, with the increasing diversity of space missions, in some complex space missions, such as cross-orbit deployment and multi-satellite networking, the upper stage emerges as a kind of aircraft with the ability of multiple starts and long-time work. In the application task of the upper stage, the existing technology often designs the upper stage orbit and the launch vehicle orbit separately, that is, the launch vehicle first sends the upper stage to a certain (elliptical) orbit agreed by both parties in advance, and then designs the upper stage trajectory. This method is difficult to achieve the overall global optimization of the launch system as a whole. SUMMARY

[0003] The purpose of the present application is to provide a launch vehicle plus upper stage joint orbit design method, which optimizes the energy ratio of the basic stage and the upper stage and maximizes the carrying capacity of the combination of the launch vehicle and the upper stage.

[0004] In order to achieve the above purpose, the present application provides a launch vehicle plus upper stage joint orbit design method, which comprises the following steps: step 1, taking the launch vehicle as the basic stage and the upper stage as the final stage, establishing a three-degree-of-freedom joint trajectory optimization model; step 2, determining the joint design orbit segment according to the characteristics of the target task; the joint design orbit segment includes the number of upper stage work times and the transfer orbit type; step 3, determining the starting point of the first work of the upper stage and completing the joint optimization; after the transfer orbit is determined, the joint orbit optimization of the launch vehicle basic stage and the first work segment of the upper stage is carried out to determine the starting point of the first work of the upper stage.

[0005] The launch vehicle plus upper stage joint orbit design method, wherein in step 1, the three-degree-of-freedom joint trajectory optimization model is a constrained nonlinear optimization problem, and the optimization methods for solving this problem include the penalty function method, the random test method and the feasible direction method.

[0006] The launch vehicle plus upper stage joint orbit design method, wherein in step 1, the three-degree-of-freedom joint trajectory optimization model includes the particle dynamics equation, the kinematics equation, the control equation and the geometric relationship equation.

[0007] The launch vehicle plus upper stage joint orbit design method, wherein in step 2, the upper stage takeoff weight constraint also needs to be considered when determining the joint design orbit segment.

[0008] The launch vehicle plus upper stage joint orbit design method, wherein in step 2, the transfer orbit type includes elliptical orbit, circular orbit and sub-orbit.

[0009] The launch vehicle plus upper stage joint orbit design method, wherein, in step 3, the first working start point of the upper stage is determined as the parking orbit between the shutdown of the basic stage of the launch vehicle and the start of the upper stage.

[0010] The launch vehicle plus upper stage joint orbit design method, wherein the parking orbit comprises a circular orbit, an elliptical orbit and a sub-orbit.

[0011] The launch vehicle plus upper stage joint orbit design method, wherein, in step 3, the three-degree-of-freedom joint trajectory optimization model established in step 1 is used to take the transfer orbit and the constraint condition as the model input, and iterative optimization is performed until the maximum launch capacity and the optimal launch performance are obtained; the constraint condition comprises the upper stage takeoff mass limit, the basic stage ground control time limit, the sub-stage landing point range limit and the maximum dynamic pressure limit.

[0012] Compared with the prior art, the launch vehicle plus upper stage joint orbit design method has the beneficial technical effects that:

[0013] The launch vehicle plus upper stage joint orbit design method provided by the application can greatly improve the launch capacity of the combination of the basic stage and the upper stage of the launch vehicle by jointly optimizing the orbits of the basic stage and the upper stage of the launch vehicle and determining the first working start point of the upper stage, and has high application value in engineering.

[0014] The launch vehicle plus upper stage joint orbit design method provided by the application is simple in design, has strong adaptability to different types of launch vehicles and upper stages, and is easy to implement in engineering. BRIEF DESCRIPTION OF DRAWINGS

[0015] The application will be further described in detail below with reference to the drawings and specific embodiments.

[0016] Figure 1 The launch vehicle plus upper stage joint orbit design method provided by the application is simple in design, has strong adaptability to different types of launch vehicles and upper stages, and is easy to implement in engineering. DETAILED DESCRIPTION

[0017] The application will be further described in detail below with reference to the drawings and specific embodiments. Figure 1 The launch vehicle plus upper stage joint orbit design method provided by the application is simple in design, has strong adaptability to different types of launch vehicles and upper stages, and is easy to implement in engineering.

[0018] The launch vehicle plus upper stage joint orbit design method of the application optimizes the joint orbit of the basic stage and the first working section of the upper stage of the launch vehicle to determine the starting point of the first working of the upper stage.

[0019] Figure 1 The figure is the flow chart of the launch vehicle plus upper stage joint orbit design method of the application.

[0020] Referring to Figure 1 The launch vehicle plus upper stage joint orbit design method of the application comprises:

[0021] Step 1, establishing a three-degree-of-freedom joint trajectory optimization model of the launch vehicle and the upper stage;

[0022] The three-degree-of-freedom joint trajectory optimization model is a constrained nonlinear optimization problem, and the optimization method for solving the problem can adopt the penalty function method, the random test method, the feasible direction method, etc., that is, the three-degree-of-freedom joint trajectory optimization model can be established by using the penalty function method, the random test method or the feasible direction method; the penalty function method, the random test method and the feasible direction method are known methods, and the application does not expand the detailed description, but does not affect the implementation of the application;

[0023] The three-degree-of-freedom joint trajectory optimization model comprises the equations of particle dynamics, kinematics, control and geometric relationship, etc.

[0024] The three-degree-of-freedom joint trajectory optimization model comprises the equations of particle dynamics, kinematics, control and geometric relationship, etc.

[0025] Step 2, determining the joint design orbit section;

[0026] The joint design orbit section is determined according to the characteristics of the target task, including the working times of the upper stage, the type of transfer orbit, etc.; when determining the joint design orbit section, the takeoff weight constraint of the upper stage also needs to be considered.

[0027] The type of transfer orbit comprises an elliptical orbit, a circular orbit and a sub-orbit, the sub-orbit is a special elliptical orbit, and the energy requirement is relatively low.

[0028] Step 3, determining the starting point of the first working of the upper stage and completing the joint optimization;

[0029] After the transfer orbit is determined, the first working section of the carrier rocket base stage and upper stage is jointly optimized to determine the first working starting point of the upper stage; determining the first working starting point of the upper stage refers to determining the parking orbit between the shutdown of the carrier rocket base stage and the start of the upper stage, which can be a circular orbit or an elliptical orbit, or a sub-orbit;

[0030] Specifically, the three-degree-of-freedom joint trajectory optimization model established in step 1 is used to iteratively optimize until the carrying capacity is maximum and the carrying performance is optimal, with the transfer orbit and constraint conditions as model inputs; the constraint conditions include upper stage take-off mass limit, base stage ground measurement and control time limit, sub-stage landing point range limit and maximum dynamic pressure limit, etc.

[0031] The application of the present application will be described below with examples.

[0032] The application of the present application will be described below with examples.

[0033] Step 1, the three-degree-of-freedom joint trajectory optimization model of the carrier rocket and the upper stage is established as follows:

[0034] Particle dynamics equation:

[0035] Kinematics equation:

[0036] Control equation:

[0037] Geometric relationship equation:

[0038] Step 2, determine the joint design orbit section

[0039] In this embodiment, the target orbit is an 850km circular orbit, the number of working times of the upper stage before entering the target orbit is determined to be 2, and the transfer orbit is an 200km×800km ellipse;

[0040] Step 3, determine the first working starting point of the upper stage, and complete joint optimization

[0041] According to the transfer orbit (200km×800km ellipse) of the upper stage, the orbit of the certain carrier rocket base stage and the certain upper stage is jointly optimized, and the orbit parameters of the separation point of the upper stage and the carrier rocket base stage, i.e. the first working starting point of the upper stage, are as follows:

[0042] Table 1 Orbit parameters of the separation point of a certain upper stage and a certain carrier rocket base stage

[0043] Name Symbol Unit Value Perigee height hp km -1599.649 Apogee height ha km 259.351 Semi-major axis a km 5707.988 Orbital inclination i (°) 88.770935 Eccentricity e — 0.162842 Longitude of ascending node Ωc (°) -79.576232 Argument of perigee ω (°) -12.812194 Mean anomaly M (°) 160.454119

[0044] In this example, the carrying capacity of the joint track optimization design is improved by 33.5% compared with the traditional design method.

[0045] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solutions of the present application are within the protection scope of the present application.

Claims

1. A method for designing the combined orbit of a launch vehicle and its upper stage, characterized in that, include: Step 1: Using the launch vehicle as the basic stage and the upper stage as the final stage, establish a three-degree-of-freedom joint ballistic optimization model. Step 2: Determine the joint design track segments based on the characteristics of the target task; The joint design track segmentation includes the upper-level operation count and the transfer track type; Step 3: Determine the starting point for the first task of the superior level and complete the joint optimization; After the transfer trajectory is determined, joint trajectory optimization is performed on the first working segment of the launch vehicle's basic stage and upper stage to determine the starting point of the upper stage's first working segment; In step 1, the three-degree-of-freedom joint ballistic optimization model is a constrained nonlinear optimization problem. The optimization methods for solving this problem include the penalty function method, the randomized trial method, and the feasible direction method. The three-degree-of-freedom joint ballistic optimization model includes the particle dynamics equation, kinematic equation, control equation, and geometric relationship equation; In step 2, when determining the joint design track segments, the upper stage takeoff weight constraint must also be considered. In step 3, the three-degree-of-freedom joint ballistic optimization model established in step 1 is used as the model input, with the transfer trajectory and constraints as the model input, and iterative optimization is performed until the carrying capacity is maximized and the carrying performance is optimal. The constraints include upper stage takeoff mass limit, basic stage ground telemetry and control time limit, sub-stage impact range limit and maximum dynamic pressure limit.

2. The method for designing the combined orbit of a launch vehicle and its upper stage as described in claim 1, characterized in that, In step 2, the transfer orbit types include elliptical orbits, circular orbits, and suborbitals.

3. The method for designing the combined orbit of a launch vehicle and its upper stage as described in claim 1, characterized in that, In step 3, determining the first working start point of the upper stage refers to determining the parking trajectory between the shutdown of the basic stage of the launch vehicle and the start-up of the upper stage.

4. The method for designing the combined orbit of a launch vehicle and its upper stage as described in claim 1, characterized in that, Parking tracks include circular tracks, elliptical tracks, and suborbitals.

Images