Real-time calculation method and device for expected airflow angle instruction

Abstract

The invention relates to a new-generation information technology, and discloses a real-time calculation method and device for an expected airflow angle instruction, so as to improve the calculation efficiency and further improve the flight performance of an aircraft. The method comprises the steps that a traditional complex solving process of a multivariate quadratic function is converted into an expected attack angle value which can be rapidly solved through finite iteration, and in each attack angle iteration process, the iteration formula is # imgabs0 #, and when the difference between the lift coefficient value calculated under the current cycle and the expected lift coefficient required for calculating the resultant force according to the aircraft control force orthogonal rule calculation method is smaller than the allowable error of the attack angle or the number of iterations is larger than or equal to the preset maximum number of iterations.

Description

Technical Field

[0001] The present invention relates to the field of computer methods and devices based on specific calculation models in new generation information technology, and in particular to a method and device for real-time solution of desired airflow angle instructions. Background Art

[0002] At present, with the increasing complexity of modern aircraft flight missions, the complex flight conditions and advanced aerodynamic shapes of aircraft have put forward higher requirements for guidance and control methods. Aircraft guidance and control are developing towards the integration of nonlinear guidance and control with stronger flight performance. Therefore, in the process of converting guidance instructions and attitude control instructions, it is necessary to directly convert the aerodynamic force function to the expected airflow angle instruction. However, the current aerodynamic force function is a multivariate quadratic function. The calculation amount of solving the expected airflow angle instruction is large and the solution speed is slow, which cannot be applied to the real-time calculation of the flight control computer system.

[0003] It can be seen that there is an urgent need for a real-time solution method and device for the expected instructions of the airflow angle model with small calculation amount and fast solution speed of nonlinear guidance control, so as to improve the flight performance of the aircraft under complex conditions.

[0004] Generally, the airflow angle includes the angle of attack, the roll angle and the sideslip angle. When the aircraft adopts the BTT (Bank To Turn) mode, the sideslip angle is generally 0. Therefore, when solving the desired airflow angle command, only the desired angle of attack and roll angle need to be calculated. Summary of the invention

[0005] The present invention aims to disclose a method and device for real-time calculation of desired airflow angle instructions, so as to improve calculation efficiency and thus enhance the flight performance of an aircraft.

[0006] To achieve the above-mentioned purpose, the method for real-time solution of the desired airflow angle instruction disclosed in the present invention includes: Step S1: Obtaining the desired lateral control force and the normal expected control force , the desired lift coefficient required for the composite force is calculated according to the orthogonal law calculation method of the aircraft control force; the desired lift coefficient The calculation formula is: ,in, , are the dynamic pressure and reference area of ​​the aircraft respectively; Step S2: Execute the angle of attack iteration process. In each angle of attack iteration process, the iteration formula is: , and determine whether to terminate the iteration according to the first condition; where, is the Mach number, is the number of iterations, and its value is 0 at initialization; is the expected angle of attack value in the next iteration cycle; is the expected angle of attack value in the current iteration cycle. During initialization, The value is 0; , According to the real-time and The lift coefficient and lift coefficient derivative obtained; the first condition is: the difference between the lift coefficient value solved in the current cycle and the expected lift coefficient in step S1 is less than the allowable error of the angle of attack; Step S3, after the angle of attack iteration is completed, generating a desired airflow angle command output according to the desired angle of attack value solved in the last iteration process.

[0007] Preferably, the dynamic pressure The calculation formula is: ;in, is the relationship between atmospheric density and altitude, is the speed of the aircraft.

[0008] Preferably, the present invention further comprises: Calculate the desired speed roll angle , and generates the desired airflow angle command output based on the calculated value.

[0009] Furthermore, a second condition for terminating the iteration is added in step S2, and the second condition is that the number of iterations is greater than or equal to the maximum number of iterations set in advance; wherein, after determining that the current number of iterations does not satisfy the first condition, it is then determined whether the current number of iterations satisfies the second condition, and if so, the iteration is terminated, otherwise, the loop iteration is continued; or, before determining that the current number of iterations does not satisfy the first condition, it is first determined whether the current number of iterations satisfies the second condition, and if so, the iteration is terminated, otherwise, whether to continue the loop iteration is determined based on the result of whether the first condition is satisfied.

[0010] To achieve the above-mentioned purpose, the present invention discloses a real-time solution device for the expected airflow angle instruction, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method when executing the computer program.

[0011] The present invention has the following beneficial effects: The traditional complex solution process of multivariate quadratic functions is converted into a desired angle of attack value that can be quickly solved after a finite number of iterations, thereby improving the solution efficiency. This can enhance the real-time solution performance of modern nonlinear guidance and control integration methods in flight control computer systems. The principle is simple, the engineering applicability is strong, and the flight performance of modern aircraft is improved.

[0012] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It is a flow chart of a method for real-time solution of expected instructions of an airflow angle model according to embodiment 1 of the present invention.

[0014] Figure 2 It is a mechanical schematic diagram of Example 1 of the present invention.

[0015] Figure 3 It is a schematic diagram of a device for real-time solving of expected instructions of an airflow angle model according to Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0016] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0017] Example 1 See also Figure 1 , is a flow chart of a method for real-time solution of expected instructions of an airflow angle model provided by an embodiment of the present invention. Figure 1 As shown, the method mainly comprises the following steps: Step 1: Obtain the desired control force input from the relative motion relationship between the aircraft and the target and the nonlinear guidance control integrated algorithm , specify the allowable error of the angle of attack , the maximum number of cycles allowed .

[0018] In this step, the lift coefficient model function of the aircraft is known and lift coefficient derivative model function Among them, the aircraft lift coefficient Usually the angle of attack and Mach number The binary function of lift coefficient model function The data is obtained in advance through aerodynamic tests, described in the form of functions, and can be bound to the flight control computer in advance.

[0019] Step 2: Calculate the expected velocity inclination angle according to the expected control force and the dynamic relationship; calculate the expected lift coefficient according to the aircraft control resultant force calculation method and the relationship between the aerodynamic coefficient and the aerodynamic force.

[0020] See also Figure 2 , is a mechanical schematic diagram provided in this embodiment. Figure 2 As shown, step 2 is: given the real-time dynamic pressure Q and reference area S, according to the launch system Oxyz and the lateral desired control force , Normal expected control force and dynamic relationship, calculate the expected speed roll angle ; Calculate the expected lift coefficient based on the calculation method of the aircraft control composite force and the relationship between the aerodynamic coefficient and the aerodynamic force .

[0021] Preferably, the step 2 specifically includes: Step 2.1: Based on the lateral desired control force and the normal expected control force They are orthogonal to each other and form a right-handed coordinate system with the direction of the aircraft velocity vector. The velocity roll angle rotates around the velocity vector direction to obtain the desired velocity roll angle. The solution method is: .

[0022] Step 2.2: Based on the height and speed of the aircraft and the relationship between atmospheric density and height , calculate the real-time dynamic pressure Q, the calculation formula is: .

[0023] Step 2.3, according to the aircraft dynamic pressure Q and the reference area S, the expected lift coefficient required for the synthetic force is calculated according to the orthogonal law calculation method of the aircraft control force. The calculation formula is: .

[0024] Step 3: Initialize the number of angle of attack iterations and the expected angle of attack value. Specifically include: Initialize the number of iterations , set the initial value of the desired angle of attack .

[0025] Step 4: Calculate the lift coefficient and lift coefficient derivative in the current iteration cycle, and update the expected angle of attack value and number of iterations in the current iteration cycle.

[0026] In other words, this step is: knowing the real-time information of the aircraft during flight Number, according to the expected angle of attack value under the current iteration cycle , and the aircraft lift coefficient model function, lift coefficient derivative model function, solve the lift coefficient under the current iteration cycle and the lift coefficient derivative , update the expected angle of attack value under the current iteration cycle ; Update the number of iterations .

[0027] Among them, the lift coefficient derivative function Data is also obtained in advance through aerodynamic tests and described in the form of functions, which can be bound to the flight control computer in advance.

[0028] Based on the above embodiment, step 4 may specifically include: Step 4.1: Know the expected angle of attack and lift coefficient in the current iteration cycle and the lift coefficient derivative In specific implementation, the real-time changes will be made according to the number of iterations. and The solution can be completed by directly substituting the lift coefficient function and the lift coefficient derivative function.

[0029] Step 4.2: Calculate the expected angle of attack value in the next iteration cycle. The calculation formula is: .

[0030] Step 4.3, update the number of iterations: .

[0031] Step 5: Execute loop iterations and determine whether the set loop judgment conditions are met: when the difference between the expected lift coefficient and the lift coefficient value calculated in the current loop is less than the allowable error of the angle of attack , or the number of iterations is less than the maximum number of sequential loops If the above conditions are not met, go to step 6.

[0032] Step 6: End the iteration and output the latest angle of attack iteration value as the desired angle of attack instruction.

[0033] In summary, the real-time solution method of the expected airflow angle command provided in this embodiment first solves the velocity roll angle according to the orthogonal relationship between the lateral force and the normal force; then iteratively solves the problem of large amount of calculation and slow solution speed in inverse solution of the airflow angle command by the aerodynamic coefficient function, optimizes the solution efficiency of the airflow angle, and improves the control performance of the aircraft.

[0034] Example 2 Corresponding to the above-mentioned embodiment 1, this embodiment discloses a device for real-time solving of expected airflow angle instructions (or referred to as "device for real-time solving of expected airflow angle instructions of airflow angle model", the so-called airflow angle model is a logical architecture for calculating expected airflow angle instructions, which will not be described in detail later), including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the following method is implemented, which at least includes: Step S1: Obtaining the desired lateral control force and the normal expected control force , the desired lift coefficient required for the composite force is calculated according to the orthogonal law calculation method of the aircraft control force; the desired lift coefficient The calculation formula is: ,in, , are the dynamic pressure and reference area of ​​the aircraft respectively.

[0035] Step S2: Execute the angle of attack iteration process. In each angle of attack iteration process, the iteration formula is: , and determine whether to terminate the iteration according to the first condition; where, is the Mach number, is the number of iterations, and its value is 0 at initialization; is the expected angle of attack value in the next iteration cycle; is the expected angle of attack value in the current iteration cycle. During initialization, The value is 0; , According to the real-time and The lift coefficient and lift coefficient derivative obtained; the first condition is: the difference between the lift coefficient value solved in the current cycle and the expected lift coefficient in step S1 is less than the allowable error of the angle of attack.

[0036] Step S3, after the angle of attack iteration is completed, generating a desired airflow angle command output according to the desired angle of attack value solved in the last iteration process.

[0037] Preferably, the dynamic pressure The calculation formula is: ;in, is the relationship between atmospheric density and altitude, is the speed of the aircraft.

[0038] Preferably, this embodiment further includes: using the formula Calculate the desired speed roll angle , and generates the desired airflow angle command output based on the calculated value.

[0039] Further, in step S2, a second condition for terminating iteration is added, and the second condition is that the number of iterations is greater than or equal to the maximum number of iterations set in advance; wherein, after judging that the current number of iterations does not meet the first condition, it is judged whether the current number of iterations meets the second condition, if the second condition is met, the iteration is terminated, otherwise, the loop iteration is continued; or, before judging that the current number of iterations does not meet the first condition, it is judged whether the current number of iterations meets the second condition, if the second condition is met, the iteration is terminated, otherwise, it is determined whether to continue the loop iteration according to the result of whether the first condition is met. In this way, the combination of the number of iterations and the accuracy further ensures that the algorithm converges in a limited number of solutions, and can prevent the situation where the number of algorithm solutions is too many due to unreasonable setting of the allowable error, thereby ensuring the real-time performance of the algorithm. In rare cases, if the number of iterations meets the condition for terminating iteration but the error range does not meet the condition, although the control accuracy will be affected in a single group of loop iteration processes (a group is a series of loop iteration processes for solving a desired angle of attack value) in such cases, in actual applications, a few times of slight reduction in control accuracy will not have a significant impact on the overall process compared to a large series of loop iteration processes.

[0040] See also Figure 3 , which is a schematic diagram of a real-time solution device for expected instructions of an airflow angle model provided in this embodiment. Figure 3 The airflow angle model expected instruction real-time solver shown is only an example and should not bring any limitation to the function and scope of use of the embodiment of the present invention.

[0041] like Figure 3 The airflow angle model expected instruction real-time solving device shown mainly includes: The navigation module is used to calculate the position, speed and other information of the aircraft, and to calculate the guidance instructions and obtain the Mach number.

[0042] The guidance module is used to store target information and characteristic information of the aircraft, and calculate the expected lateral force and expected normal force based on the relative motion relationship between the aircraft and the target and the guidance control law.

[0043] The aerodynamic force calculation module is used to store the aerodynamic force model function and calculate the aerodynamic force coefficient in real time according to variables such as the real-time angle of attack and Mach number.

[0044] The airflow angle calculation module is used to calculate the expected airflow angle in real time based on the expected lateral force, expected normal force, and current Mach number calculated by the guidance instructions.

[0045] The data interaction logic of the above functional modules refers to the above steps and will not be elaborated on here.

[0046] In summary, the real-time solution method and device for the expected airflow angle command respectively disclosed in the above two embodiments of the present invention convert the complex solution process of the traditional multivariate quadratic function into a desired angle of attack value that can be quickly solved after a finite number of iterations, thereby improving the solution efficiency, and can enhance the real-time solution performance of the modern nonlinear guidance and control integration method in the flight control computer system. The principle is simple, the engineering applicability is strong, and the flight performance of modern aircraft is improved.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for real-time calculation of a desired airflow angle instruction, characterized in that: include: Step S1: Obtaining the desired lateral control force and the normal expected control force , the desired lift coefficient required for the composite force is calculated according to the orthogonal law calculation method of the aircraft control force; the desired lift coefficient The calculation formula is: ,in, , are the dynamic pressure and reference area of ​​the aircraft respectively; Step S2: Execute the angle of attack iteration process. In each angle of attack iteration process, the iteration formula is: , and determine whether to terminate the iteration according to the first condition; where, is the Mach number, is the number of iterations, and its value is 0 at initialization; is the expected angle of attack value in the next iteration cycle; is the expected angle of attack value in the current iteration cycle. During initialization, The value is 0; , According to the real-time and The lift coefficient and lift coefficient derivative obtained; the first condition is: the difference between the lift coefficient value calculated in the current cycle and the expected lift coefficient in step S1 is less than the allowable error of the angle of attack; Step S3: after the angle of attack iteration is completed, a desired airflow angle command output is generated according to the desired angle of attack value solved in the last iteration process.

2. The method for real-time calculation of the desired airflow angle command according to claim 1, characterized in that: Dynamic Pressure The calculation formula is: ;in, is the relationship between atmospheric density and altitude, is the speed of the aircraft.

3. The method for real-time calculation of the desired airflow angle command according to claim 1, characterized in that: Also includes: By formula Calculate the desired speed roll angle , and generates the desired airflow angle command output based on the calculated value.

4. The method for real-time calculation of the desired airflow angle command according to any one of claims 1 to 3, characterized in that: In the step S2, a second condition for terminating the iteration is added, and the second condition is that the number of iterations is greater than or equal to the maximum number of iterations set in advance; wherein, after determining that the current number of iterations does not satisfy the first condition, it is then determined whether the current number of iterations satisfies the second condition. If the second condition is satisfied, the iteration is terminated, otherwise, the loop iteration is continued; or, before determining that the current number of iterations does not satisfy the first condition, it is first determined whether the current number of iterations satisfies the second condition. If the second condition is satisfied, the iteration is terminated, otherwise, whether the loop iteration is continued is determined based on the result of whether the first condition is satisfied.

5. A device for real-time calculation of a desired airflow angle instruction, 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, the method for real-time solution of the desired airflow angle instruction described in any one of claims 1 to 4 is implemented.

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