Advances in Aerospace Science and Applications. ISSN 2277-3223 Volume 4, Number 1 (2014), pp. 85-90 © Research India Publications http://www.ripublication.com/aasa.htm

Flight Simulation Using Graphical User Interface

A. Kalra, P. Anand and S. Singh

Amity Institute of Aerospace Engineering, Amity University Uttar Pradesh, Sector-125, Noida, INDIA.

Abstract Graphical User Interface for flight simulation of aircraft is developed to analyze the change in motion variables with respect to various longitudinal, lateral and directional control inputs. Effects of stability and control derivatives on motion variables are also studied using Graphical User Interface. Firstly, Non-linear six degrees of freedom equations of motion of airplane dynamics are solved using Runge-Kutta 4th order method. Secondly, Graphical User Interface is developed in order to make the program more user friendly and easily accessible. Programs for solving non-linear differential equations and Graphical User Interface are written in the MATLAB R2012b. The advantages of using Graphical User Interface for flight simulation are that the user can change the initial conditions of all motion variables, control inputs and corresponding response of the aircraft can be analyzed. With the developed Graphical User Interface, user having no prior knowledge of programming can simulate flight trajectory for any initial conditions and control inputs. The time response of flight variable and effect of stability and control derivatives on the flight response are presented graphically and discussed in the paper. The paper briefly describes the flight dynamics, mathematical model, Initial flight data, the Graphical User Interface and discusses observations on one of the control input under simulation.

1. Introduction The use of flight simulation by generating a dynamic model of an aircraft has become an innate need of all aviation industries. It is a method through which the in-flight reactions of an aircraft against different parametric dimensions, environmental conditions and control inputs can be visualized through the developed outputs in the

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form of graphs, calculated values and/or even in the form of real environment. The reason it has become an integral need of any research and development team is because flight simulation has made a major contribution to improve aviation safety. It also offers considerable financial saving to airlines and reduces the environment impact of civil aviation. Pilots can practice for situations that would be impractical in airborne training exercises, while researches can study and improve efficiency and safety for these situations.

This simulation implies the method of using the mathematical model of an aircraft, which are non-linear differential equations. In order to solve these non-linear six degrees of freedom equations of motion of airplane dynamics the method of Runge-Kutta fourth-order is used. The input flight conditions when set for computation using MATLAB provides with explicit information about the desired flight parameters. The developed graphic user interface can be used by researchers and designers to observe the effects of changes in the geometric, longitudinal and lateral aerodynamic characteristics.

2. Estimation of Flight Variables 2.1 Flight Dynamics It is the science of air vehicle’s orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three dimensions about the vehicle's center of mass, known as pitch, roll and yaw. Roll is defined as acting about the longitudinal axis, positive with the starboard (right) wing down. The yaw is about the vertical body axis, positive with the nose to starboard. Pitch is about an axis perpendicular to the longitudinal plane of symmetry, positive nose up. A fixed-wing aircraft increases or decreases the lift generated by the wings when it pitches nose up or down by increasing or decreasing the angle of attack. The roll angle is also known as bank angle on a fixed-wing aircraft, which usually "banks" to change the horizontal direction of flight. An aircraft is usually streamlined from nose to tail to reduce drag making it typically advantageous to keep the sideslip angle near zero.

2.2 Mathematical Model The dynamic model is given by: Force equations,

mTC

mSqgrvqwu x ++−+−= θsin&

(1)

yCmSqgpwruv +++−= φθ sincos&

(2)

zCmSqgqupvw +++−= φθ coscos&

(3)

Kinematic equations, θφθφφ tancostansin rqp ++=& (4)

Flight Simulation Using Graphical User Interface 87

φφθ sincos rq −=& (5)θφθφψ seccossecsin rq +=& (6)

Moment equations,

[ ])()()(

1 222 zyzxznxzlzxzzx

IIIIrqCICIsSqIII

p −+−+−

=&

(7)

[ ])()(1 22xzxzm

yIIprIrpCsSq

Iq −+−−=&

(8)

[ ])(()()()(

1 222 yxxxzzyxxzlxznxxzzx

IIIIpqIIIIrqCICIsSqIII

r −+++−−+−

=&

(9)

2.3 Initial Flight Data The data used in the program can be changed by the user to any value as per the requirements and realize the performance for different aircrafts at different flights conditions. By default it is set for Boeing 747 with an initial mach number 0.9.

Table 1: Flight Data.

FLIGHT CONDITIONS u p q r phi theta si H

306 0 0 0 0 0 0 12192GEOMETRIC

Rho g c B S Mass e AR 1.225 9.8067 8.324 59.643 185.8061 288756.9 0.8 6.962

T Ix Iy Iz Ixz 944000 24675886 44877574 67384152 1315143 LONGITUDINAL

CLq Cmq CLM CDM CmM CLde Cmde CLo 6.58 -25 0.2 0.25 -0.1 0.3 -1.2 0.08 CDo Cmo CLa CDa Cma CLadot Cmadot 0.025 0.01 5.5 0.47 -1.6 0.006 -9.0

LATERAL Clb Cnb Clp Cnp Clr Cnr Clda Cnda -0.1 0.2 -0.3 0.2 0.2 -0.325 0.014 0.003

2.4 Graphical User Interface (GUI) In the GUI as shown in Fig. 1, different tabs and buttons are provided to ensure the ease of access and simplicity of use that can be well tailored to the tasks. User can change the different inputs, even the initial data, as per the need and just with the click on ‘compute’ button can get the output. The code behind the ‘compute’ button takes the data from the different modules of the program and displays the combined output.

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The general instruction displayed on the home screen of GUI is another helping tool for the user.

Fig. 1: The graphical user interface for Flight Simulation. The simulation is so generated that any input control deflection is given to the

system after ten seconds of initial run time. This is done in order to make the aircraft reach a stabilized state and overcome any initial moments if present.

2.4.1 Observation on Elevator Input As shown in the Fig. below, an elevator input with time steps of 3-2-1-1 and an elevator deflection of 6, -6, 3 & -3 degrees is given correspondingly.

Fig. 2: Control Deflection Vs Time graph showing the Elevator Input. The study of graphs generated with this particular elevator deflection provides with

an in depth observation of certain crucial in-flight parameters such as the angle of attack, sideslip, roll, pitch and yaw angles and rates along with the velocities in all the directions. Fig. 3 depicts the relation of all these parameters against time in accordance with the given control input. It can be observed that the angle of attack first increases

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the 6-DoF model. It is hoped that there will continue to be rapid progress made in the data acquisition and parameter identification processes, as well as in the 6-DoF dynamic modeling effort.

References

[1] R C Nelson (1989), Flight Stability and Automatic Control, McGraw-hill,

United States of America [2] C D Perkins and R Hage (1949), Airplane Performance Stability and Control,

John Wiley, pp 374-470 [3] T M Adami and J. J Zhu, 6DOF Flight Control of Fixed-Wing Aircraft, Senior

Member, AIAA, pp 1611-1615 [4] MATLAB® Creating Graphical User Interfaces, Copyright 2000–2013 by

The MathWorks, Inc [5] Marcello Napolitano (2011), Aircraft Dynamics: From Modeling to

Simulation, Wiley pp 325-398