Measurement test method for acting by unfolding aerodynamic moment of folding rudder

Abstract

The invention discloses a measurement test method for working by unfolding aerodynamic torque of a folding rudder, and belongs to the technical field of wind tunnel special tests. The problem that in the prior art, the error between the result obtained through a traditional folding rudder unfolding performance measuring method and a real aircraft is large is solved. According to the invention, folding rudder unfolding tests are respectively carried out under a wind-load-free condition and a wind-load-containing condition, an effective driving torque in a folding rudder unfolding process is measured through a balance, and a rudder surface rotation angle process under the wind-load-free condition and the wind-load-containing condition is obtained through high-speed camera shooting; obtaining a relational expression between the effective driving torque and the unfolding angle of the folding rudder, and integrating the relational expression to obtain the acting of the effective driving torque; the tail angular velocity is obtained according to the moment when the folding rudder is unfolded in place, and the acting of the effective driving torque is subtracted from the tail kinetic energy when the folding rudder is unfolded in place, so that the acting of the aerodynamic torque is obtained. According to the invention, the accuracy of folding rudder unfolding performance testing is effectively improved, and the method can be applied to safety testing of folding rudder unfolding.

Description

Technical Field

[0001] The invention relates to a measurement test method for the work done by the aerodynamic torque of a folding rudder during its deployment, and belongs to the technical field of special wind tunnel tests. Background Art

[0002] In order to adapt to the strict constraints of space, the control surfaces of the aircraft adopt a folding design to reduce the outer envelope size. The foldable surfaces can be quickly deployed during flight to enhance control capabilities. Whether the folding rudder can be deployed safely and smoothly is a key assessment of the aircraft design, including whether the folding rudder can be deployed normally under the work of aerodynamic hindering loads, and whether the impact load when deployed into place under the work of aerodynamic promoting loads will damage the rudder surface structure.

[0003] In the prior art, wind tunnel tests are widely used as the most economical assessment method for folding rudder safety tests. However, the deployment assessment test of the folding rudder requires the use of a real model, a folding rudder and its driving source. Due to the limitation of the wind tunnel size, the blockage of the real model in the wind tunnel is too large to conduct the test. The previous practice is to shorten and simplify the forebody of the real model, retain the real folding rudder installation part, carry out a deployment test without driving force, and obtain the deployment process of the rudder surface. However, the results obtained can only qualitatively analyze the deployment performance of the folding rudder, because the flow in which the folding rudder is located changes after the forebody of the real model is shortened and simplified, and the aerodynamic force it receives is inconsistent with that of the real model; or a scaled model is used to measure the rudder surface load to obtain its static load at different deployment angles, but this ignores the dynamic load of the folding rudder deployment process. The above method is not applicable when accurately evaluating the folding and deployment performance, and the obtained folding rudder deployment performance is inaccurate.

[0004] In summary, a test method for measuring the work done by the aerodynamic torque of a folding rudder is needed. Summary of the invention

[0005] A brief overview of the present invention is provided below in order to provide a basic understanding of certain aspects of the present invention. It should be understood that this overview is not an exhaustive overview of the present invention. It is not intended to identify key or important parts of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] In view of this, in order to solve the problem that the results obtained by the traditional folding rudder deployment performance measurement method in the prior art have a large error with the actual aircraft, the present invention provides a measurement test method for the aerodynamic torque work of the folding rudder deployment.

[0007] The technical solution is as follows: A test method for measuring the work done by the aerodynamic torque of a folding rudder, comprising the following steps: S1. Conduct a folding rudder deployment test under windless conditions, deploy a folding rudder model with a balance installed at the root, measure the effective driving torque during the folding rudder deployment process using the balance, use a high-speed photography tool to obtain the real-time folding rudder deployment angle, and obtain the relationship between the effective driving torque and the folding rudder deployment angle based on the obtained rudder surface rotation angle history under windless conditions, and integrate the relationship to obtain the work done by the effective driving torque; S2. Carry out a folding rudder deployment test under wind load conditions, set up a folding rudder model without a balance installed, use high-speed photography tools to obtain the real-time folding rudder deployment angle, and obtain the rudder surface rotation angle history under wind-free conditions. Perform polynomial fitting on the folding rudder deployment angle history after digital filtering and smoothing pre-processing, and then take a derivative of the folding rudder deployment angle history to obtain the angular velocity versus time curve. The terminal angular velocity is obtained according to the moment when the folding rudder is fully deployed, and the aerodynamic torque work is obtained by subtracting the work done by the effective driving torque from the final kinetic energy when the folding rudder is in place.

[0008] Furthermore, in S1, the effective driving torque The torque measured by the balance , the rudder surface rotation angle history under no wind load conditions is , whose unit is radians; Effective driving torque It is expressed as: ; ;

[0009] The effective driving torque The unit is Newton meter, the torque measured by the balance The unit is Newton meter. is the theoretical driving torque of the driving source, its unit is N·m, is the friction torque during the rotation process, its unit is Nm, is the moment of inertia of the moving part around the axis of rotation, its unit is kg·m², is the angular acceleration under no wind load conditions, that is, the second derivative of the folding rudder deployment angle with respect to time, and its unit is radian / second²; According to the effective driving torque , the relationship between the effective driving torque and the folding rudder deployment angle is obtained , the work done by the effective driving torque is obtained through the integration algorithm , whose unit is joule; Work done by effective driving torque It is expressed as: .

[0010] Furthermore, in S2, the rudder surface rotation angle history under wind load conditions is: , whose unit is radian, is pre-processed by digital filtering and smoothing method, and a 6th-order polynomial curve fitting is performed to obtain the mathematical expression of the change of the folding rudder deployment angle with time. The angular velocity change function with time is obtained by taking a derivative. According to the time when the folding rudder is deployed, , calculate the final angular velocity , using the final kinetic energy minus the work done by the effective driving torque, we get the work done by the aerodynamic torque; The mathematical expression of the change of the folding rudder deployment angle over time is expressed as: ;

[0011] in, is the time, its unit is / second, They are the constant terms of the 6th-order polynomial curve fitting, the moment when the folding rudder is fully deployed The unit is / second; The angular velocity changes with time as a function of: ;

[0012] in, Indicates the rudder surface rotation angle history under wind load conditions Take a derivative; Final angular velocity It is expressed as: ;

[0013] Aerodynamic torque work It is expressed as: ;

[0014] Among them, the aerodynamic torque does work The unit is joule.

[0015] The beneficial effects of the present invention are as follows: the present invention uses aerodynamic torque work as an evaluation indicator, effectively avoiding the problem that the aerodynamic torque and the unfolding angle history of the folding rudder unfolding process of the simplified test model of the forebody shortening are difficult to simulate at the same time, and can accurately evaluate the actual unfolding performance of the folding rudder; the present invention adopts a balance measurement method to obtain the effective driving torque under no-wind load conditions, and can accurately deduct the influence of the folding rudder rotation friction torque. In the unfolding test data processing under wind load conditions, the angular velocity at the moment the folding rudder is fully unfolded is introduced to calculate the aerodynamic torque work, which can effectively avoid the error influence of the large deviation of the second derivative of the angle time curve and the fluctuation of the intermediate process data, and improve the accuracy of the measurement; the measurement results of the present invention can quickly and accurately evaluate the rationality of the driving torque and test the impact load resistance of the folding rudder, avoid problems during flight, improve safety, and save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part 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 A schematic flow chart of a test method for measuring the work done by the aerodynamic torque of a folding rudder during deployment; Figure 2 It is a schematic diagram of the forces during the unfolding process of the folding rudder; Figure 3 Schematic diagram for solving the work done by the effective driving torque; Figure 4 The present invention is a schematic flow chart of an embodiment of a method for measuring the work done by the aerodynamic torque of a folding rudder during deployment. DETAILED DESCRIPTION

[0017] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0018] refer to Figure 1-Figure 4 The present embodiment is described in detail, a test method for measuring the work done by the aerodynamic torque of the folding rudder during deployment, specifically comprising the following steps: S1. Conduct a folding rudder deployment test under windless conditions, deploy a folding rudder model with a balance installed at the root, measure the effective driving torque during the folding rudder deployment process using the balance, use a high-speed photography tool to obtain the real-time folding rudder deployment angle, and obtain the relationship between the effective driving torque and the folding rudder deployment angle based on the obtained rudder surface rotation angle history under windless conditions, and integrate the relationship to obtain the work done by the effective driving torque; S2. Conduct a folding rudder deployment test under wind load conditions, set up a folding rudder model without a balance, use a high-speed photography tool to obtain the real-time folding rudder deployment angle, obtain the rudder surface rotation angle history under wind load conditions, perform polynomial fitting on it after digital filtering and smoothing pre-processing, and then perform a derivative on the folding rudder deployment angle history to obtain the angular velocity versus time curve, obtain the terminal angular velocity according to the moment when the folding rudder is fully deployed, and obtain the aerodynamic torque work by subtracting the effective driving torque work from the terminal kinetic energy when the folding rudder is fully deployed; Specifically, refer to Figure 2 , The force in the process of folding rudder deployment includes driving torque, aerodynamic torque, inertia torque and friction torque. Since the real folding rudder and driving source are used for the test, the work done by driving torque, friction torque and inertia torque is consistent with the real model. According to the principle of energy conservation, as long as the aerodynamic torque work of the folding rudder deployment of the simplified test model with shortened forebody is consistent with the real model, the real deployment performance of the folding rudder can be fully reflected. The aerodynamic torque work of the folding rudder deployment of the simplified test model with shortened forebody is consistent with that of the real model and can be expressed as: ; ; ;

[0019] in, The aerodynamic torque work of the simplified test model for forebody shortening, is the aerodynamic torque work of the real model, The folding rudder deployment angle of the simplified test model was shortened to shorten the forebody. The aerodynamic moment of the simplified test model for forebody shortening is The unfolding angle of the folding rudder of the real model. is the aerodynamic moment of the real model.

[0020] Although the deployment process and aerodynamic torque of the test model are inconsistent with the real ones, the aerodynamic torque work can meet the assessment requirements. Therefore, the aerodynamic torque work of the test model is the most important indicator for evaluating whether the wind tunnel test simulation conditions meet the assessment requirements. In this embodiment, the aerodynamic torque work of the forebody shortened simplified model during the folding rudder deployment test is accurately measured; The effective driving torque is the theoretical driving torque minus the friction torque. The friction torque is the driving torque lost due to mechanical friction of the rotating parts. Engineering experience has found that the ratio of friction torque to theoretical driving torque can reach 25%. Therefore, it cannot be ignored and needs to be deducted.

[0021] Furthermore, in S1, the effective driving torque The torque measured by the balance The effective driving torque is the value of the theoretical driving torque minus the friction torque. The rudder rotation angle history under no wind load conditions is , its unit is radian (rad); Effective driving torque It is expressed as: ; ;

[0022] The effective driving torque The unit is Newton meter (N m), the torque measured by the balance The unit is Newton meter (N m). is the theoretical driving torque of the driving source, and its unit is Newton meter (N m). is the friction torque during the rotation process, its unit is Newton meter (N m), is the moment of inertia of the moving part around the axis of rotation, its unit is kilogram meter squared (kg m²), is the angular acceleration under no wind load conditions, that is, the second derivative of the folding rudder deployment angle with respect to time, and its unit is radian / second² (rad / s²); After measuring the effective driving torque, the relationship between the effective driving torque and the folding rudder deployment angle is obtained: , the work done by the effective driving torque is obtained through the integration algorithm , its unit is joule (J); Work done by effective driving torque It is expressed as: .

[0023] Furthermore, in S2, the rudder surface rotation angle history under wind load conditions is: , whose unit is radian (rad), is pre-processed by digital filtering and smoothing method, and a 6th-order polynomial curve fitting is performed to obtain the mathematical expression of the change of the folding rudder deployment angle with time. The angular velocity change function with time is obtained by taking a derivative. According to the time when the folding rudder is deployed, , calculate the final angular velocity , using the final kinetic energy minus the work done by the effective driving torque, we get the work done by the aerodynamic torque; The mathematical expression of the change of the folding rudder deployment angle over time is expressed as: ;

[0024] in, is time, its unit is / second (s), They are the constant terms of the 6th-order polynomial curve fitting, the moment when the folding rudder is fully deployed The unit is / second (s), the moment when the folding rudder is fully deployed The unit of the angular velocity of the corresponding folding rudder when it is fully deployed is radian per second (rad / s); The angular velocity changes with time as a function of: ;

[0025] in, Indicates the rudder surface rotation angle history under wind load conditions Take a derivative; Final angular velocity It is expressed as: ;

[0026] Aerodynamic torque work It is expressed as: ;

[0027] Among them, the aerodynamic torque does work The unit is joule (J).

[0028] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, with respect to the scope of the present invention, which is defined by the appended claims.

Claims

1. A test method for measuring the work done by the aerodynamic torque of a folding rudder, characterized in that: The following steps are involved: S1. Conduct a folding rudder deployment test under windless conditions, deploy a folding rudder model with a balance installed at the root, measure the effective driving torque during the folding rudder deployment process using the balance, use a high-speed photography tool to obtain the real-time folding rudder deployment angle, and obtain the relationship between the effective driving torque and the folding rudder deployment angle based on the obtained rudder surface rotation angle history under windless conditions, and integrate the relationship to obtain the work done by the effective driving torque; S2. Carry out a folding rudder deployment test under wind load conditions, set up a folding rudder model without a balance installed, use high-speed photography tools to obtain the real-time folding rudder deployment angle, and obtain the rudder surface rotation angle history under wind-free conditions. Perform polynomial fitting on the folding rudder deployment angle history after digital filtering and smoothing pre-processing, and then take a derivative of the folding rudder deployment angle history to obtain the angular velocity versus time curve. The terminal angular velocity is obtained according to the moment when the folding rudder is fully deployed, and the aerodynamic torque work is obtained by subtracting the work done by the effective driving torque from the final kinetic energy when the folding rudder is in place.

2. A test method for measuring the aerodynamic torque work of a folding rudder according to claim 1, characterized in that: In S1, the effective driving torque The torque measured by the balance , the rudder surface rotation angle history under no wind load conditions is , whose unit is radians; Effective driving torque It is expressed as: ； ； The effective driving torque The unit is Newton meter, the torque measured by the balance The unit is Newton meter. is the theoretical driving torque of the driving source, its unit is N·m, is the friction torque during the rotation process, its unit is Nm, is the moment of inertia of the moving part around the axis of rotation, its unit is kg·m², is the angular acceleration under no wind load conditions, that is, the second derivative of the folding rudder deployment angle with respect to time, and its unit is radian / second²; According to the effective driving torque , the relationship between the effective driving torque and the folding rudder deployment angle is obtained , the work done by the effective driving torque is obtained through the integration algorithm , whose unit is joule; Work done by effective driving torque It is expressed as: 。 3. A test method for measuring the aerodynamic torque work of a folding rudder according to claim 2, characterized in that: In S2, the rudder surface rotation angle history under wind load conditions is: , whose unit is radian, is pre-processed by digital filtering and smoothing method, and a 6th-order polynomial curve fitting is performed to obtain the mathematical expression of the change of the folding rudder deployment angle with time. The angular velocity change function with time is obtained by taking a derivative. According to the time when the folding rudder is deployed, , calculate the final angular velocity , using the final kinetic energy minus the work done by the effective driving torque, we get the work done by the aerodynamic torque; The mathematical expression of the change of the folding rudder deployment angle over time is expressed as: ； in, is the time, its unit is / second, They are the constant terms of the 6th-order polynomial curve fitting, the moment when the folding rudder is fully deployed The unit is / second; The angular velocity changes with time as a function of: ； in, Indicates the rudder surface rotation angle history under wind load conditions Take a derivative; Final angular velocity It is expressed as: ； Aerodynamic torque work It is expressed as: ； Among them, the aerodynamic torque does work The unit is joule.

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