KR101392255B1 - Computer readable recording medium for recording analysis program for 6 degrees of freedom of aircraft - Google Patents

Abstract

The present invention relates to a computer-readable recording medium on which a program for supporting basic steering stability analysis, stall, and spin analysis of a KC-100 aircraft can be performed through 6 degrees of freedom simulation.
As a form for realizing this, the present invention is a computer-readable recording medium on which is recorded a six degree-of-freedom analysis program for an aircraft, comprising: (a) a computer for controlling an aircraft's altitude, speed, power and trim options Supporting a flight condition to be included; (b) initializing existing state variables and existing aeronautical US data, weight data and engine thrust data; (c) calculating a trim condition of the aircraft with respect to the flight condition input in the step (a); (d) updating the state variable according to the trim state calculated in the step (c); (e) calculating and updating an atmospheric condition for the flight condition input in the step (a); (f) enabling the computer to input a control input including a value relating to each control surface of the aircraft and a value relating to a power lever; (g) invoking necessary variable values from the simulation database to calculate the aeronautical uncorrection data, weight data, and engine thrust data according to the flight condition input in the step (a) and the steering input value input in the step (f) ; And (h) updating the state variable according to the aeronautical uncertainty data, weight data, and engine thrust data calculated in the step (g). A computer readable recording medium is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a computer readable recording medium,

The present invention relates to a computer-readable recording medium on which an aircraft's six degrees-of-freedom analysis program is recorded. More particularly, the present invention relates to an analysis of basic handling stability, stall, and spin of a KC- The present invention relates to a computer readable recording medium on which a program for supporting the execution of a program is provided.

In general, when the aircraft exceeds the stall angle during flight, not only the air flow around the aircraft but also the movement of the aircraft caused thereby becomes very complicated.

The continuous autorotation phenomenon occurring at a higher angle of attack than the stall angle after the stall is called spin.

The penetration of the spin motion proceeds through an initial spin stage where the trajectory is a parabola and then proceeds to a developed spin stage in which the trajectory is almost perpendicular to the ground. The spin analysis is based on this fully developed spin, It is common practice to carry out steps. Most aircraft do not enter fully developed spins in one revolution.

The possibility of recovery from spin is also a crucial factor for flight safety, stall and spin are the major causes of accidents in small aircraft (aviation) and stall departures are one of the most common causes of accidents .

On the other hand, according to Part 23 of the Korean Airworthiness Standards (KAS), it is required that a normal (N, Normal) class aircraft should be able to recover for a spin that lasts longer than the one spin or three seconds . In this case, the possibility of recovering from a single spin spin means a margin of safety for restoring the aircraft by providing the appropriate steering force when the recovery of the stall is delayed.

The KC-100 is a 310 horsepower four-seater single-piston engine. The aircraft is under development in accordance with KAS Part 23, and its spin characteristics are an important part of the aircraft design goals.

Therefore, it is very important to predict whether the KC-100 aircraft is in the spin mode and its characteristics. The present inventors have found that the KC-100 aircraft's six freedom To develop an analysis program.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing points, and it is an object of the present invention to provide an apparatus and a method for analyzing basic control stability of a KC-100 aircraft and analysis of stall and spin through 6 degrees of freedom The present invention provides a computer readable recording medium on which a program for supporting a computer readable recording medium is provided.

According to another aspect of the present invention, there is provided a computer-readable medium having recorded thereon a six degree-of-freedom analysis program for an aircraft, the program comprising: (a) Supporting the input of a flight condition including a trim option; (b) initializing existing state variables and existing aeronautical US data, weight data and engine thrust data; (c) calculating a trim condition of the aircraft with respect to the flight condition input in the step (a); (d) updating the state variable according to the trim state calculated in the step (c); (e) calculating and updating an atmospheric condition for the flight condition input in the step (a); (f) enabling the computer to input a control input including a value relating to each control surface of the aircraft and a value relating to a power lever; (g) invoking necessary variable values from the simulation database to calculate the aeronautical uncorrection data, weight data, and engine thrust data according to the flight condition input in the step (a) and the steering input value input in the step (f) ; And (h) updating the state variable according to the aeronautical uncertainty data, weight data, and engine thrust data calculated in the step (g). A computer readable recording medium is provided.

According to a preferred embodiment, the simulation database in step (g) may comprise an aerodynamic database, a weight database, and an engine database.

1 is a flowchart for explaining a process of each step performed by the 6 DOF analysis program of an aircraft according to the present invention;
FIG. 2 is a diagram showing the result of analyzing URMC for the shape of a KC-100 aircraft; FIG.
Fig. 3 schematically shows the final shape of a KC-100 aircraft; Fig.
FIG. 4 is a view showing a result of analyzing a normal spin mode for each shape by using a vertical wind tunnel test result of a KC-100 aircraft, shape and weight conditions. FIG.
5 is a view showing a result of performing a spin mode analysis on a recovery operation shape by using a six degree of freedom analysis program of an aircraft according to the present invention.
6 shows an example of a model for a steering input configured for six degrees of freedom analysis for spin motions.
FIG. 7 is a diagram showing a one-rotation spin analysis result of a KC-100 aircraft analyzed using a six degree-of-freedom analysis program of an aircraft according to the present invention. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a flow chart for explaining a process of each step performed by the 6 DOF analysis program of an aircraft according to the present invention.

A six degree of freedom analysis program for an aircraft according to the present invention includes a first step (S101) for supporting a computer to input a flight condition including an altitude, a speed, a power and a trim option of an aircraft; A second step (S102) of initializing existing state variables and existing aeronautical uncertainty data, weight data and engine thrust data; A third step (S103) of calculating a trim condition of the aircraft with respect to the flight condition inputted in the first step; A fourth step (S104) of updating the state variable according to the trim state calculated in the third step; A fifth step (S105) of calculating and updating an atmospheric condition for the flight condition inputted in the first step; A sixth step (S106) of enabling the computer to input a control input including a value relating to each control surface of the aircraft and a value relating to a power lever; Weight data and engine thrust data according to the flight condition inputted in the first step and the steering input value inputted in the sixth step by calling necessary variable values from the simulation database, Step S107; And an eighth step (S108) of updating the state variable according to the aeronautical uncertainty data, weight data, and engine thrust data calculated in the seventh step.

According to a preferred embodiment, the simulation database in the seventh step may comprise an aerodynamic database, a weight database, and an engine database.

More specifically, referring to FIG. 1, a first step (S101) performed by the six degree-of-freedom analyzing program of an aircraft according to the present invention is a step of inputting flight state information of an aircraft to be analyzed. For example, the user can set the aircraft shape and weight condition through the first step (S101) provided by the program, and define the altitude, speed, power condition and trim option to be calculated.

The second step (S102) performed by the 6 degree-of-freedom analyzing program of the aircraft according to the present invention is a step of initializing the program. For example, the user initializes the existing state variable before performing the six degrees-of-freedom analysis of the aircraft through the second step (S102) provided by the present program, Data and engine thrust data can be initialized.

The third step (S103) and the fourth step (S104) performed by the six degree-of-freedom analyzing program of the aircraft according to the present invention are executed by the aircraft trim for the altitude and speed condition of the aircraft for performing the six degrees- ) State and updating the state variable. For example, in the case of a flight test, basically, before the test is performed, the aircraft is started with the trim being trimmed. In the third step (S103) and the fourth step (S104) , It is possible to analytically calculate the trim to update the state variable, thereby simulating the situation in which the aircraft starts in the trimmed state.

The fifth step (S105) performed by the 6 degree-of-freedom analyzing program of the aircraft according to the present invention is a step of calculating an atmospheric condition as a start part for performing an analysis of six degrees of freedom of an actual aircraft. For example, the user can update the waiting condition for the flight condition input in the first step (S101) through the process of the fifth step (S105) provided by the present program.

The sixth step (S106) performed by the six degrees-of-freedom analysis program of the aircraft according to the present invention is a step of inputting the same values as those input by the pilot during the actual flight test. For example, the user inputs a control input including a value relating to each control surface of the aircraft and a value relating to a power lever through a process of a sixth step (S106) provided by the present program . According to a preferred embodiment, the steering input value may be predefined or a control loop may be added that can modify the steering input value according to circumstances.

The seventh step S107 performed by the six degree-of-freedom analysis program of the aircraft according to the present invention is a step of computing a six degree-of-freedom degree of freedom equation based on the simulation database. For example, the user can calculate the aircraft weight and MOI data, aerodynamic data, and engine data through the process of step 7 (S107) provided by the present program. More specifically, the seventh step (S107) provided by the program calls the necessary variable values from the simulation database (not shown), and determines the flight condition inputted in the first step (S101) Weight data, and engine thrust data according to the steering input value input in step S106.

According to a preferred embodiment, the simulation database (not shown) in the seventh step S107 may include an aerodynamic database, a weight database, and an engine database, which are also part of the program Module). ≪ / RTI > In addition, the program may be designed to modify the database data file when the information about the aircraft changes, or to modify the program module if necessary, so that the interpretation can easily be performed on other aircraft.

The eighth step (S108) performed by the six degrees-of-freedom analysis program of the aircraft according to the present invention is a step of updating the state variable according to the aeronautical uncertainty data, weight data and engine thrust data calculated in the seventh step.

According to a preferred embodiment, the program may further perform a time step (not shown) after performing the process of the eighth step (S108).

The six degrees-of-freedom analyzing program including the steps of performing the first to eighth steps described above supports a computer to perform basic manipulation stability analysis, stall, and spin analysis of an aircraft.

According to the six degree of freedom analysis program according to the present invention, it is very useful for predicting the flight characteristics before the flight test.

The research processes performed by the present inventors in connection with the development of the 6 DOF analysis program according to the present invention will be described below. Hereinafter, the KC-100 aircraft will be described as an example, but it is apparent that the present invention can be applied to all aircraft including a KC-100 aircraft.

[ KC -100 spin recovery characteristics prediction]

Two approaches are generally used to predict the spin recovery characteristics of an aircraft. One is the Unbalanced Rolling Moment Coefficient (URMC) method and the other is the Tail Damping Power Factor (TDPF) method. Generally, it is known that the URMC method can predict more accurately than the TDPF method. Therefore, the present inventors have applied the URMC method to predict the spin recovery characteristic of the KC-100 aircraft. In the shape design of the KC-100 aircraft, the fuselage length of the aircraft was determined at the level of the aircraft of the same class, and the spin requirement was the recovery from one rotation spin. Therefore, the design goal of URMC is similar to that of a similar model capable of one spin spin recovery. The URMC analysis of the KC-100 shape is similar to that of a similar model as shown in FIG.

The final shape of the designed KC-100 aircraft is shown in Fig.

[ KC -100 spin mode  analysis]

Various kinds of wind tunnel tests are carried out according to the purpose from the beginning of the development of the aircraft. Among them, the wind tunnel test to predict the spin characteristics is a vertical wind tunnel test. This test has a wide range of angle of attack to be applied compared to a general wind tunnel test, and a rotary balance test (test for the rotation of an aircraft) .

In the rotary balance test, the force and moment acting on the model are measured in the vertical rotation current situation by dynamically inclining the rotation axis of the aircraft with respect to the aircraft speed vector, and by analyzing the aerodynamic data in the abnormal flow (high angle of attack and side slip angle) The stall stall, post stall gyration, spin entry, spin expansion and spin recovery characteristics can be predicted.

In the KC-100 aircraft, a rotary balance test was performed to extract the aerodynamic force required for interpreting and predicting the spin motion accompanied by a sudden turn at a high angle of attack. The obtained coefficients were applied to the equation of motion to determine spin mode analysis and spin characteristics .

For the vertical wind tunnel test of the KC-100 aircraft, a 13% reduction model was used for the rotary balance test and the forced vibration test (Forced Oscillation Test) for an angle of attack of 0 ° ~ 90 ° and a side slip angle of -10 ° ~ Respectively.

The rotary balance test of the KC-100 aircraft was carried out in the Large-Amplitude Multi-Purpose Facility (LAMP) owned by Bihrle Applied Research GmbH, Neuburg, Germany. The KC-100 aircraft is equipped with a 310-horsepower propeller with three vanes, but does not include the propeller effect test.

Spin refers to a motion in which the aircraft has a high angle of attack after the stall angle, and descends rapidly while rotating around the vertical axis relative to the ground. This spin motion is a complicated motion in which yawing, rolling, and pitching motions are combined at the same time, resulting in a side slip angle at a high angle of attack and a vibration characteristic. Spins are classified into initial spin, advanced spin, normal spin, and spin recovery stages. The normal spin phase is a dynamic, equilibrium region that can be analyzed and compared with the initial spin phase or the advanced spin phase. The analysis of the normal spin phase can be used to approximate the spin mode of the spinning aircraft You can. However, since the equations for the dynamic equilibrium state are complexly connected, a numerical method is required for the analysis.

Normal spin phase The aircraft motion equation is that the aircraft is a rigid body, and the atmospheric velocity vector V and the spin rotation velocity vector Ω are always parallel and vertical, V is equal to the descending velocity, and the angular velocity vector is constant, the time per turn is constant and Ixz = 0 because the body axis and the principle axis of the aircraft coincide with each other and finally the side force is considerably smaller than lift and drag, The under-home motion equation can be simplified to the following equation (1), which is an approximate non-dimensional equation expressed only by the angle of attack, the side slip angle, and the dimensionless turnover rate ω.

(2) where S is the aircraft wing area, b is the aircraft wing span, c is the mean aerodynamic chord (MAC), and Ixx, Iyy , And Izz is the moment of inertia for each axis.

The non-dimensional turn ratio (ω), the angle of attack (α), and the side slip angle (β) can be obtained from Equation (1) expressed in equilibrium state of the aerodynamic coefficient and moment of inertia for each axis.

Equation (1) is related to Bihrle Jr. to analyze the normal spin mode. (Bihrle, W. Jr. and Barnhart, B., 1983, "Spin Prediction Techniques," Journal of Aircraft , Vol. 20, No. 2, pp. 97-101), the 6-degree-of-freedom analysis program of the aircraft as described in FIG. 1 was developed and analyzed.

As a result of vertical wind tunnel test of KC-100 aircraft, normal spin mode of each shape was analyzed using shape and weight conditions. As shown in Fig. 4, the KC-100 aircraft has the right spin mode at an angle of attack of about 30 °. In the case of the left spin, the aerodynamic force and moment of inertia are close to each other, but there is no spin mode.

In order to confirm the spin recovery possibility, the spin mode analysis was performed on the recovery operation shape using the 6 DOF analysis program of the aircraft according to the present invention, and the analysis results are shown in FIG. As shown in FIG. 5, the result of the six degrees-of-freedom analysis program of the aircraft according to the present invention is that the KC-100 aircraft is expected to be able to recover the spin when it enters the normal spin.

[ KC -100 1 Prediction of spin spin recovery characteristics]

For the accuracy of the normal spin mode interpretation, Bihrle Jr. (Bihrle, W. Jr. and Barnhart, B., 1983, "Spin Prediction Techniques," Journal of Aircraft , Vol. 20, No. 2, pp. 97 ~ 101), the results of the free spin test and the flight test are in good agreement with the results of the normal spin prediction. Shin, YH, Lee, SJ, and Byun, JK, "Spin Characteristics Prediction of KTX-1 with Analytical Method and Its Flight Test Results," Journal of the See KSAS, Vol.26, No.5, pp1 ~ 17) also show that the predicted results agree well with the flight test results. However, it is noted that the correlation may not fit well in a general aviation configuration with a very steep spin mode. Therefore, additional analysis was needed on the recovery of the KC-100 aircraft in one rotation for one spin.

For this purpose, the present inventors carried out a 6 DOF analysis using the six degrees-of-freedom analysis program of the aircraft as described in FIG.

Since the general nonlinear equation of motion is applied, the 6-degree-of-freedom analysis is based on the stability of the developed spin mode and the difficulty of entering or recovering from spin, as well as departure, roll reversal, post- stall gyration, and so on. However, in order to perform the analysis through the 6-degree-of-freedom analysis, extensive aerodynamic data, including dynamic derivatives and rotary balance data, are obtained during the forced vibration test, need.

The results of 6 degrees of freedom analysis may differ from the results of flight tests due to differences in the Reynolds number between the actual airframe and the model or the error of the mean coefficient.

The present inventors have developed a 6-degree-of-freedom motion model based on data by converting aerodynamic data for 6-DOF analysis into a database and converting the aircraft weight data and engine data into a database. The flowchart of the 6 degrees-of-freedom analysis program is shown in Fig. 1 described above.

The aerodynamic database of the KC-100 aircraft was constructed by modeling the low-speed wind tunnel test in the low-angle of attack area, the vertical wind tunnel test in the high-angle-of-attack area, and the rotary balance and forced vibration test data (Kim, JS and Seo, HS, KC -100 Aerodynamic Database V.3.2 Report , Korea Aerospace Industries, LTD, pp.22-60).

Meanwhile, the model for the control input is constructed as shown in FIG. 6 for 6 degrees of freedom analysis of the spin motion. The elevator is fully displaced in the nose lifting direction in the vicinity of the stalling angle for spin entry, while the rudder is provided with a fully displaced input in the direction of the spin entrance, while the aircraft maintains the horizontal attitude while increasing the angle of attack to the stall angle. After entering the spin, recovery operation was performed after a time of one rotation or three seconds, and it was judged whether or not it was recoverable in one revolution.

The results of the KC-100 one-rotation spin analysis using the six degrees-of-freedom analysis program of the aircraft according to the present invention are shown in FIG. 7, and it is predicted that spin recovery in one rotation is possible. Therefore, it was expected that the KAS 23.221 one-turn spin requirement would be satisfactory.

The results of the analysis using the 6 DOF analysis program of the aircraft according to the present invention may not be in perfect agreement with the flight test results in the spin motion, but it is judged that the recovery possibility prediction is possible for one rotation spin. One spin spin recovery characteristic of the KC-100 aircraft will be confirmed in future spin flight tests.

The six degree of freedom analysis program for an aircraft according to the present invention can be implemented as a computer readable code on a computer readable recording medium. For example, the computer readable recording medium may be a ROM, a RAM, a CD-ROM, a magnetic tape, a hard disk, a floppy disk, a flash memory, an optical data storage device, , Transmission over the Internet).

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (2)

A six-degree-of-freedom analysis program for predicting a spin characteristic of an aircraft, the program comprising:
Performing a 6-degree-of-freedom analysis on the basis of a result of the flight test performed on the aircraft, and displaying a result of the rotational spin analysis of the aircraft according to a result of the 6-degree of freedom analysis,
The step of performing the 6-DOF analysis may include:
(a) allowing a computer to input flight conditions including an aircraft's altitude, speed, power and trim options;
(b) initializing existing state variables and existing aeronautical US data, weight data and engine thrust data;
(c) calculating a trim condition of the aircraft with respect to the flight condition input in the step (a);
(d) updating the state variable according to the trim state calculated in the step (c);
(e) calculating and updating an atmospheric condition for the flight condition input in the step (a);
(f) enabling the computer to input a control input including a value relating to each control surface of the aircraft and a value relating to a power lever;
(g) invoking necessary variable values from the simulation database to calculate the aeronautical uncorrection data, weight data, and engine thrust data according to the flight condition input in the step (a) and the steering input value input in the step (f) ; And
(h) updating the state variable according to the aeronautical uncertainty data, weight data, and engine thrust data calculated in the step (g)
Wherein the step of displaying the rotational spin analysis result displays information on whether or not the airplane is to be restored in one rotation spin on the screen of the computer. media. The method according to claim 1,
Wherein the simulation database in the step (g) includes an aerodynamic database, a weight database, and an engine database.

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