A design method for aircraft engine servo control system

Abstract

The present application belongs to the field of aircraft engine design and is a design method for an aircraft engine servo control system. The method realizes the optimal design of the servo control system by establishing a strong coupling relationship between each boundary condition and the design calculation result, and establishing an optimization function according to the coupling relationship. The fast convergence of the optimization function is achieved by setting restriction conditions. Since all commonly used boundary conditions are used, the cross-coupling design between the accessories of the servo control system is realized. Since the optimization calculation is performed with the boundary conditions that meet the design requirements as the initial values, the designed servo control system will definitely meet the design requirements, the calculation result has a high confidence level, and will not increase useless design burden and cost. Without affecting the function and performance, the size, weight and design difficulty of the servo control system are reduced.

Description

Technical Field

[0001] The present application relates to the field of aircraft engine design, and in particular to a design method for an aircraft engine servo control system. Background Art

[0002] The servo guide vanes of future aircraft engine control systems will have many cross-sections, and the number of actuators will generally exceed 30. If we still follow the design ideas of traditional servo control systems and set too high requirements on their capabilities, it will not only increase useless design burdens and costs, but also make the external structure design of the engine more complicated.

[0003] The existing engine servo control system has the following problems:

[0004] 1) Boundary condition extraction is fuzzy and the confidence of theoretical design calculation results is poor;

[0005] 2) The design method is relatively simple, mainly relying on increasing the size of the accessory or improving the accessory capacity, and "over-design" adds useless design burden and cost;

[0006] 3) There is a lack of cross-coupling design between the accessories within the servo control system.

[0007] Therefore, how to reduce the size, weight and design difficulty of the servo control system while ensuring the function and performance of the servo control system is a problem that needs to be solved. Summary of the invention

[0008] The purpose of this application is to provide a method for designing an aircraft engine servo control system to solve the problems of simple design, heavy weight, complex design and poor confidence of the servo control system in the prior art.

[0009] The technical solution of the present application is: a method for designing an aircraft engine servo control system, comprising: setting theoretical calculation formulas for the servo system driving force, servo system flow, and actuator motion time according to various boundary conditions of the servo control system design process, establishing a coupling relationship between each boundary condition and the three-dimensional size of the actuator, the theoretical calculation driving force of the actuator, the theoretical calculation flow of the servo system, and the theoretical calculation motion time of the actuator; using the coupling relationship to establish an optimization function and set up restriction conditions for the optimization function; determining the optimization target, giving the initial value of each boundary condition, obtaining the difference between the optimization result and the optimization target, establishing a residual function, judging whether the difference meets the residual accuracy requirement, and if not, correcting the initial value of the boundary condition through the difference and repeating the optimization; if satisfied, executing the next step; obtaining the final results of the three-dimensional size of the actuator, the theoretical calculation of the actuator driving force, the theoretical calculation of the servo system flow, and the theoretical calculation of the actuator motion time to complete the optimization.

[0010] Preferably, the optimization function is:

[0011] Among them, A1 is the diameter of the rodless cavity of the actuator, A2 is the diameter of the piston rod of the actuator, A3 is the stroke of the actuator, A4 is the number of actuators installed, A5 is the required time for the full stroke movement of the actuator, 6 is the pressure relationship after the servo pump, A7 is the design flow of the servo valve, A8 is the required load force of the geometric guide vane, B1 is the three-dimensional size of the actuator, B2 is the theoretical calculated driving force of the actuator, B3 is the theoretical calculated flow of the servo system, and B4 is the theoretical calculated movement time of the actuator.

[0012] Preferably, the restriction conditions of the priority function are: B1≤external dimension restriction; B2≥A8; B3 matches the characteristics of A6; B4≤A5.

[0013] Preferably, the theoretical calculation formula of the servo system driving force is:

[0014] F 收进max =P 泵后 ×A 有杆 -P 回油 ×A 无杆 ;

[0015] F 伸出max =P 泵后 ×A 无杆 -P 回油 ×A 有杆

[0016] Among them, F 收进max F is the theoretical maximum driving force of a single actuator in the retracted state; 伸出max P is the theoretical maximum driving force of a single actuator in the extended state; 泵后 is the pressure after the servo pump; P 回油 is the oil return pressure; A 有杆 A is the area of ​​the actuator rod cavity; 无杆 is the rodless cavity area of ​​the actuator.

[0017] Preferably, the theoretical calculation formula for the servo system flow is:

[0018]

[0019] Q 总 =Q 作动1 +Q 作动2 +...

[0020] Among them, Q 作动 is the flow rate of a single actuator; Q 总 is the servo system flow; A 无杆 is the rodless cavity area of ​​the actuator; L 作动 is the actuator stroke; T 作动 The time required for the actuator to move through its full stroke.

[0021] Preferably, the theoretical calculation formula for the actuator motion time is:

[0022]

[0023]

[0024] Where ρ is the density of the working medium: η is the flow efficiency: t 伸出 Actuator extension time: t 收进 The actuator retraction time: L 作动 is the actuator stroke: Q 伺服阀 is the servo valve flow rate corresponding to a single actuator: Pr is the return oil pressure of the control device: Ps is the inlet pressure of the control device: C is the area ratio of the two chambers of the actuator: F 负载 A is the load required by the geometric guide vane; 有杆 The rod cavity area of ​​the actuator.

[0025] The present application discloses a design method for an aircraft engine servo control system. The method achieves optimal design of the servo control system by establishing a strong coupling relationship between each boundary condition and a design calculation result, and establishing an optimization function based on the coupling relationship. The method achieves rapid convergence of the optimization function by setting restriction conditions. Since all commonly used boundary conditions are used, cross-coupling design between the accessories of the servo control system is achieved. Since the optimization calculation is performed using boundary conditions that meet the design requirements as initial values, the designed servo control system will inevitably meet the design requirements, the calculation result has a high confidence level, and will not increase useless design burden and cost. The size, weight and design difficulty of the servo control system are reduced without affecting the function and performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0027] Figure 1 This is a schematic diagram of the overall process of this application;

[0028] Figure 2 This is the correspondence diagram between the boundary conditions of this application and the design calculation results. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application.

[0030] A design method for an aircraft engine servo control system, such as Figure 1 As shown, the following steps are included:

[0031] Step S100, according to the boundary conditions of the servo control system design process, the servo system driving force, the servo system flow rate, and the actuator movement time theoretical calculation formula are set, and the coupling relationship between the boundary conditions and the actuator three-dimensional size, the actuator theoretical calculation driving force, the servo system theoretical calculation flow rate, and the actuator theoretical calculation movement time is established;

[0032] The design process of the servo control system basically includes eight boundary conditions, namely the diameter of the rodless cavity of the actuator, the diameter of the piston rod of the actuator, the stroke of the actuator, the number of actuators installed, the required time for the full stroke movement of the actuator, the pressure relationship after the servo pump, the design flow of the servo valve, and the required load force of the geometric guide vanes. There is a strong coupling relationship between the boundary conditions and the design calculation results. After the boundary conditions are confirmed, four design calculation results can be obtained, including the three-dimensional size of the actuator, the theoretical calculation driving force of the actuator, the theoretical calculation flow of the servo system, and the theoretical calculation movement time of the actuator. Among them, the three-dimensional size of the actuator does not need to be calculated by formula.

[0033] Preferably, the theoretical calculation formula of the servo system driving force is:

[0034] F 收进max =P 泵后 ×A 有杆 -P 回油 ×A 无杆 ;

[0035] F 伸出max =P 泵后 ×A 无杆 -P 回油 ×A 有杆

[0036] Among them, F 收进max F is the theoretical maximum driving force of a single actuator in the retracted state; 伸出max P is the theoretical maximum driving force of a single actuator in the extended state; 泵后 is the pressure after the servo pump; P 回油 is the oil return pressure; A 有杆 A is the area of ​​the actuator rod cavity; 无杆 is the rodless cavity area of ​​the actuator.

[0037] Preferably, the theoretical calculation formula for the servo system flow is:

[0038]

[0039] Q 总 =Q 作动1 +Q 作动2 +...

[0040] Among them, Q 作动 is the flow rate of a single actuator; Q 总is the servo system flow; A 无杆 is the rodless cavity area of ​​the actuator; L 作动 is the actuator stroke; T 作动 The time required for the actuator to move through its full stroke.

[0041] Preferably, the theoretical calculation formula for the actuator motion time is:

[0042]

[0043]

[0044] Where ρ is the density of the working medium: η is the flow efficiency: t 伸出 Actuator extension time: t 收进 The actuator retraction time: L 作动 is the actuator stroke: Q 伺服阀 is the servo valve flow rate corresponding to a single actuator: Pr is the return oil pressure of the control device: Ps is the inlet pressure of the control device: C is the area ratio of the two chambers of the actuator: F 负载 A is the load required by the geometric guide vane; 有杆 The rod cavity area of ​​the actuator.

[0045] Through the theoretical calculation formulas of the servo system flow rate, the theoretical calculation formulas of the servo system flow rate, and the theoretical calculation formulas of the actuator motion time, a strong coupling relationship between each boundary condition and the three-dimensional size of the actuator, the theoretical calculation driving force of the actuator, the theoretical calculation flow rate of the servo system, and the theoretical calculation motion time of the actuator was established, providing a basis for the subsequent optimization of various parameters.

[0046] like Figure 2 As shown, in step S200, an optimization function is established by using the coupling relationship, and restriction conditions of the optimization function are set; the optimization function is:

[0047] Among them, A1 is the diameter of the rodless cavity of the actuator, A2 is the diameter of the piston rod of the actuator, A3 is the stroke of the actuator, A4 is the number of actuators installed, A5 is the required time for the full stroke movement of the actuator, 6 is the pressure relationship after the servo pump, A7 is the design flow of the servo valve, A8 is the required load force of the geometric guide vane, B1 is the three-dimensional size of the actuator, B2 is the theoretical calculated driving force of the actuator, B3 is the theoretical calculated flow of the servo system, and B4 is the theoretical calculated movement time of the actuator.

[0048] Preferably, the restriction conditions of the priority function are: B1≤external dimension restriction; B2≥A8; B3 matches the characteristics of A6; B4≤A5.

[0049] By setting the optimization function and establishing constraints, the optimization function can converge quickly during optimization.

[0050] Step S300, determine the optimization target, give the initial values ​​of each boundary condition, obtain the difference between the optimization result and the optimization target, establish a residual function, and determine whether the difference meets the residual accuracy requirement. If not, correct the initial values ​​of the boundary conditions by the difference and repeat the optimization; if satisfied, execute the next step;

[0051] The optimization target can be set according to the needs. For example, the minimum outer dimension can be set as the target value, or the actuator weight can be minimized, the actuator performance can be optimized, and other targets can be set. By establishing different optimization targets according to the needs, different optimization targets correspond to different residual functions, and different optimization results can be obtained. The residual accuracy requirements are set manually.

[0052] Step S400, obtaining the final results of the actuator's three-dimensional dimensions, the actuator's driving force theoretical calculation, the servo system flow theoretical calculation, and the actuator's motion time theoretical calculation, and completing the optimization.

[0053] When designing an aircraft engine servo control system, a strong coupling relationship between each boundary condition and the design calculation results is established, and an optimization function is established based on the coupling relationship to achieve optimal design of the servo control system. Rapid convergence of the optimization function is achieved by setting restriction conditions. Since all commonly used boundary conditions are used, cross-coupling design between various accessories of the servo control system is achieved. Since the boundary conditions that meet the design requirements are used as initial values ​​for optimization calculation, the designed servo control system will inevitably meet the design requirements, the calculation results have a high degree of confidence, and will not increase useless design burdens and costs. Without affecting the function and performance, the size, weight and design difficulty of the servo control system are reduced.

[0054] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for designing an aircraft engine servo control system, characterized in that: include: According to the boundary conditions of the servo control system design process, the theoretical calculation formulas of the servo system driving force, servo system flow rate and actuator motion time are set, and the coupling relationship between the boundary conditions and the three-dimensional size of the actuator, the theoretical calculation driving force of the actuator, the theoretical calculation flow rate of the servo system and the theoretical calculation motion time of the actuator is established; Use coupling relationships to establish optimization functions and set up constraints for optimization functions; Determine the optimization target, give the initial values ​​of each boundary condition, obtain the difference between the optimization result and the optimization target, establish the residual function, and determine whether the difference meets the residual accuracy requirement. If not, correct the initial value of the boundary condition by the difference and repeat the optimization; if satisfied, proceed to the next step; Obtain the final results of the actuator's three-dimensional dimensions, the actuator's driving force theoretical calculation, the servo system's flow theoretical calculation, and the actuator's motion time theoretical calculation to complete the optimization; The optimization function is: Among them, A1 is the diameter of the rodless cavity of the actuator, A2 is the diameter of the piston rod of the actuator, A3 is the stroke of the actuator, A4 is the number of actuators installed, A5 is the required time for the full stroke movement of the actuator, 6 is the pressure relationship after the servo pump, A7 is the design flow of the servo valve, A8 is the required load force of the geometric guide vane, B1 is the three-dimensional size of the actuator, B2 is the theoretical calculated driving force of the actuator, B3 is the theoretical calculated flow of the servo system, and B4 is the theoretical calculated movement time of the actuator; The restriction conditions of the optimization function are: B1≤external dimension limit; B2≥A8; B3 matches the characteristics of A6; B4≤A5; The theoretical calculation formula of the servo system driving force is: F 收进max =P 泵后 ×A 有杆 -P 回油 ×A 无杆 ; F 伸出max =P 泵后 ×A 无杆 -P 回油 ×A 有杆 Among them, F 收进max F is the theoretical maximum driving force of a single actuator in the retracted state; 伸出max P is the theoretical maximum driving force of a single actuator in the extended state; 泵后 is the pressure after the servo pump; P 回油 is the oil return pressure; A 有杆 A is the area of ​​the actuator rod cavity; 无杆 is the rodless cavity area of ​​the actuator; The theoretical calculation formula for the servo system flow is: Q 总 =Q 作动1 +Q 作动2 +... Among them, Q 作动 is the flow rate of a single actuator; Q 总 is the servo system flow; A 无杆 is the rodless cavity area of ​​the actuator; L 作动 is the actuator stroke; T 作动 The time required for the actuator to move through its full stroke; The theoretical calculation formula for the actuator motion time is: Where ρ is the density of the working medium: η is the flow efficiency: t 伸出 Actuator extension time: t 收进 The actuator retraction time: L 作动 is the actuator stroke: Q 伺服阀 is the servo valve flow rate corresponding to a single actuator: Pr is the return oil pressure of the control device: Ps is the inlet pressure of the control device: C is the area ratio of the two chambers of the actuator: F 负载 A is the load required by the geometric guide vane; 有杆 The rod cavity area of ​​the actuator.

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