A landing guidance method adapted to thrust response large lag

Abstract

The application discloses a landing guidance method suitable for thrust response large lag, which utilizes a polynomial guidance to calculate a reference trajectory, considers engine response characteristics in the calculation process of the polynomial guidance method, solves the technical problem caused by the engine command thrust response large lag in the flight process, and enables the aircraft to complete the flight task according to the trajectory planned by the polynomial guidance. The application obtains the relationship between the command acceleration and the response acceleration through the engine characteristics, compensates the delay characteristics into the acceleration command by using the reference trajectory of the polynomial, obtains the polynomial landing guidance method considering the thrust response large lag, and can guarantee that the output command is the target acceleration calculated by the polynomial, and accurately realizes the target speed position control of landing.

Description

Technical Field

[0001] This invention relates to a landing guidance method that adapts to large thrust response lag, belonging to the field of aircraft guidance and control technology. Background Technology

[0002] Landing guidance technology is a key guidance technology for achieving landing requirements such as rocket return, lunar landing, and Mars landing. During the landing process, it is necessary to meet the requirements for landing position, velocity, and acceleration.

[0003] Polynomial guidance technology is a technique that plans a trajectory in real time to satisfy initial and landing point constraints. Current polynomial guidance generally only considers the relationship between the current position and velocity during flight, the landing point position and velocity, and control commands, or treats the engine's response characteristics as a simple time delay. However, simple time delays cannot accurately characterize engine properties; second-order or even higher-order characteristics can more realistically describe the thrust response.

[0004] As the key actuator for implementing guidance commands, the engine's response delay can cause the acceleration commands generated by polynomial programming to fail to be accurately executed. This prevents the engine from flying to the predetermined target along the trajectory planned by the polynomial guidance method, resulting in deviations in the landing point's position, velocity, and acceleration. Even if the engine's response characteristics are considered simply as a time delay for guidance command compensation, the difference in response characteristics will still introduce control errors. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a landing guidance method that adapts to large thrust response lag. This method incorporates engine thrust response characteristics, target acceleration calculated by polynomials, and reference trajectory into the control commands, thereby solving the problem of command acceleration response lag and achieving the goal of eliminating errors and thus realizing precise landing.

[0006] The technical solution of this invention is: a landing guidance method adapting to large thrust response hysteresis, comprising:

[0007] Calculate the reference trajectory based on the target point information and the current velocity and position information;

[0008] Calculate the target acceleration based on the reference trajectory;

[0009] Construct an equivalent model of acceleration response;

[0010] Using the reference trajectory, obtain the differential equation expression for the command acceleration;

[0011] Calculate the command acceleration based on the differential equation expression.

[0012] Furthermore, a reference trajectory is calculated based on the target point information and the current velocity and position information.

[0013] Furthermore, the calculation of the reference trajectory based on the target point information and the current velocity and position information specifically involves:

[0014] S G =S TG

[0015] J G =J TG +S TG ·T

[0016]

[0017]

[0018]

[0019] Among them, R TG V TG A TG J TG S TG Target position, velocity, acceleration, acceleration derivative, and second-order acceleration derivative; R G V G A G J G S G : The current position, velocity, acceleration, acceleration derivative, and acceleration second derivative of the aircraft; T: Remaining flight time.

[0020] Furthermore, the target acceleration is calculated based on the reference trajectory: A G =12(R) TG -R G ) / T 2 +6(V TG -V G ) / T+A TG .

[0021] Furthermore, based on the engine response delay characteristics, an equivalent acceleration response model is constructed as follows: τ is the response time, ξ is the damping coefficient, and A m A represents the actual response acceleration. C Let be the command acceleration, and s be the Laplace operator.

[0022] Furthermore, using the reference trajectory, the differential equation expression for the command acceleration is obtained as follows:

[0023]

[0024] Among them, A′ m A″ is the first derivative of the actual response acceleration. m " is the second derivative of the actual response acceleration.

[0025] Further, the calculation of the command acceleration based on the differential equation expression includes:

[0026] τ is the response time, and ξ is the damping coefficient.

[0027] Furthermore, the reference trajectory position is a fourth-order function of time, the reference trajectory velocity is a cubic function of time, and the reference trajectory acceleration is a quadratic function of time.

[0028] A computer-readable storage medium storing a computer program, characterized in that, when executed by a processor, the computer program implements the steps of the landing guidance method adapted to large thrust response hysteresis.

[0029] A landing guidance device adapted to large thrust response hysteresis includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: when the processor executes the computer program, it implements the steps of the landing guidance method adapted to large thrust response hysteresis.

[0030] The advantages of this invention compared to the prior art are:

[0031] (1) It takes into account the second-order response characteristics of engine thrust, rather than simply the time delay, which can more realistically compensate for the command error caused by engine thrust response.

[0032] (2) By using the reference trajectory term of the polynomial as the differential term of the acceleration command, the guidance command can be made continuous, thus avoiding the problem of acceleration command jump caused by the differential action. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0034] To better understand the above technical solutions, the technical solutions of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0035] The following description, in conjunction with the accompanying drawings, provides a more detailed explanation of a landing guidance method adapted to large thrust response hysteresis, as provided in the embodiments of this application. Specific implementation methods may include (e.g.) Figure 1 As shown):

[0036] 1) Calculate the reference trajectory based on the target information and the current velocity and position information;

[0037] 2) Calculate the target acceleration based on the reference trajectory;

[0038] 3) Construct an equivalent model of acceleration response;

[0039] 4) Using the reference trajectory, obtain the differential equation expression for the command acceleration;

[0040] 5) Calculate the command acceleration;

[0041] In one possible implementation, in step 1), the reference trajectory position is a fourth function of time, the reference trajectory velocity is a cubic function of time, and the reference trajectory acceleration is a quadratic function of time.

[0042] S G =S TG

[0043] J G =J TG +S TG ·T

[0044]

[0045]

[0046]

[0047] R TG V TG A TG J TG S TG Target position, velocity, acceleration, jerk, jerk derivative;

[0048] R G V G A G J G S G Current position, velocity, acceleration, jerk, jerk derivative;

[0049] T: Remaining flight time;

[0050] Furthermore, in one possible implementation, in step 2), the target acceleration is calculated using the reference trajectory.

[0051]

[0052] Solve for J TG S TG We can obtain:

[0053]

[0054] Substitute it into the reference trajectory acceleration model in step 2).

[0055]

[0056] In one possible implementation, step 3) involves constructing an equivalent model of the acceleration response.

[0057] The engine characteristic equivalent model adopts a second-order equivalent model.

[0058]

[0059] τ is the response time, ξ is the damping coefficient, and F C For command thrust, F m For the target thrust;

[0060]

[0061] A m Actual response acceleration; A C Command acceleration;

[0062] m 实际 Actual mass, m 制导估计 Guidance estimation quality.

[0063] Assume that the deviation between the estimated guidance mass and the actual mass is small and can be ignored.

[0064]

[0065] Furthermore, in one possible implementation, in step 4), the differential equation expression for the command acceleration is obtained using the reference trajectory from step 1).

[0066] A C =(τ 2 s 2 +2ξτs+1)A m

[0067] =τ 2 A″ m "+2ξτA′ m +A m

[0068] Let the response acceleration A mCalculating acceleration A using polynomials G equal.

[0069] A m =A G

[0070] A m =A TG +J TG ·T+S TG ·T 2 / 2

[0071] The first and second derivatives can be represented by the jerk in the reference trajectory quantity and its derivative.

[0072] A′ m =J TG +S TG ·T

[0073] A″ m " = S TG

[0074] In one possible implementation, step 5) involves calculating the command acceleration.

[0075]

[0076] J TG S TG By substituting the expression, we can obtain a display expression for the remaining flight time, the target velocity-position acceleration, and the current velocity-position.

[0077]

[0078] The solution provided in this application embodiment can be divided into the following five steps:

[0079] 1. Calculate the reference trajectory based on the target information and the current velocity and position information;

[0080] S G =S TG

[0081] J G =J TG +S TG ·T

[0082]

[0083]

[0084]

[0085] 2. Calculate the target acceleration based on the reference trajectory;

[0086] According to V in step 1 G R G The expression can be obtained

[0087]

[0088] Solve for J TG S TG We can obtain:

[0089]

[0090] Substitute into the reference trajectory acceleration model in step 1):

[0091]

[0092] 3. Construct an equivalent model of acceleration response;

[0093] The engine characteristic equivalent model adopts a second-order equivalent model.

[0094]

[0095]

[0096] Let m 实际 =m 制导估计 ,

[0097]

[0098] 4. Using the reference trajectory, obtain the differential equation expression for the command acceleration;

[0099] A C =(τ 2 s 2 +2ξτs+1)A m

[0100] =τ 2 A″ m "+2ξτA′ m +A m

[0101] Let the response acceleration A m Calculating acceleration A using polynomials G equal.

[0102] A m =A G

[0103] A m =A TG +J TG ·T+S TG ·T2 / 2

[0104] The first and second derivatives can be represented by the jerk in the reference trajectory quantity and its derivative.

[0105] A′ m =J TG +S TG ·T

[0106] A″ m " = S TG

[0107] 5. Calculate the command acceleration;

[0108]

[0109] J TG S TG By substituting the expression, you can obtain a display expression for the remaining flight time, target position, speed, acceleration, and current speed and position.

[0110]

[0111] This application provides a computer-readable storage medium storing computer instructions that, when executed on a computer, cause the computer to perform... Figure 1 The method described.

[0112] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0113] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0114] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0115] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0116] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0117] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

[0118] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A landing guidance method adapted to large thrust response lag, characterized in that, include: Calculate the reference trajectory based on the target point information and the current velocity and position information; Calculate the target acceleration based on the reference trajectory; Construct an equivalent model of acceleration response; Using the reference trajectory and the equivalent model of acceleration response, the differential equation expression of the command acceleration is obtained; Calculate the command acceleration based on the differential equation expression.

2. The landing guidance method for adapting to large thrust response lag as described in claim 1, characterized in that, The calculation of the reference trajectory based on the target point information and the current velocity and position information is specifically as follows: in, , , , , Target position, velocity, acceleration, acceleration derivative, and acceleration second derivative; , , , , The aircraft's current position, velocity, acceleration, acceleration derivative, and acceleration second derivative; Remaining flight time.

3. The landing guidance method for adapting to large thrust response lag according to claim 2, characterized in that, Calculate the target acceleration based on the reference trajectory: .

4. A landing guidance method adapting to large thrust response lag as described in claim 2, characterized in that, Based on the engine response delay characteristics, an equivalent acceleration response model is constructed as follows: ; For response time, The damping coefficient is... This refers to the actual response acceleration; For command acceleration, For the Laplace operator.

5. A landing guidance method adapting to large thrust response lag as described in claim 4, characterized in that, Using the reference trajectory and the equivalent model of acceleration response, the differential equation expression for the command acceleration is obtained as follows: in, The first derivative of the actual response acceleration. This is the second derivative of the actual response acceleration.

6. A landing guidance method adapting to large thrust response hysteresis according to claim 4, characterized in that, The calculation of the command acceleration based on the differential equation expression includes: ; For response time, is the damping coefficient.

7. A landing guidance method for adapting to large thrust response lag as described in claim 1, characterized in that, The reference trajectory position is a fourth-order function of time, the reference trajectory velocity is a cubic function of time, and the reference trajectory acceleration is a quadratic function of time.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 7.

9. A landing guidance device adapted to large thrust response lag, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 7.

Images