Essay: Flight Dynamics And Control: A Literature Review.

You are expected to write a literature review to further your understanding of flight dynamics and control. This will be for a minimum of four published papers, critiquing the theory, process and their findings and outcomes. The papers should be linked and progressive in the understanding.

You will chose a hypothesis linked to a current problem in flight dynamics and control for example:

• Efficient fault detection, identification and recovery approaches for flight control
• The accuracy and limitations of aircraft simulation for SPO testing
• Effective stability augmentation systems for commercial aircraft
• Efficient ways of increasing autonomy in UAV flight control

Hypothesis related to flight dynamics and control

For the purpose of pilot training, the simulators were designed. Later, the flight simulation has the advantage to help in an aircraft design. The flight simulators play a significant role in the design of aircraft. The flight simulator lowers the cost of the lifecycle. This is due to the process of testing and the development of the complex aircraft system.  This could be done before the actual testing of flight. The necessary data will be provided by the simulator. The data will be used to assess the systems and aircraft behavior and performance. The simulation model will be constructed to analyze the flight vehicles’ stability characteristics, mission, and performance. The main objective is to construct the 3 DOF longitudinal flight simulation model. It will be done in Simulink. The simulation model permits the air craft’s rapid configuration & flight dynamic analysis. The Simulink model will have the capacity for solving longitudinal equations of the motion of the aircraft. The control derivatives and the aerodynamic stability aids to determine the aircraft's characteristics of longitudinal dynamic stability. The model will give the results for determining whether the aircraft is dynamically and statically stable longitudinally.

The aircraft flight simulation is the component of the complete process of an aircraft design. It is time consuming, iterative and complex in nature. The technical steps are included in this process. It needs software with simulation and modeling like Simulink/Matlab. The fundamental steps for the design of an aircraft which is related to the flight simulation involves

1. Explaining an aircraft geometry and mass
2. Discovering the characteristics of an aircraft aerodynamics
3. Generating simulation of an aircraft flight
4. Creating flight control laws
5. Finishing the process of design

The determination of the characteristics of an aircraft aerodynamics is one of the vital steps for the study of simulation and modeling (Deiler, 2017). After the aerodynamic moments and forces act on the aircraft, equation of the motion can be solved (Nebylov, 2013). There are 3 methods to get the characteristics of an aerodynamics for the geometric configuration. The methods are listed below.

1. Wind tunnel testing
2. Analytical predication
3. Flight testing

For an aircraft, determining the aerodynamic data analytically   is the less-expensive and quick method (AERODYNAMIC ANALYSIS OF EAGLE WINGLETS ON AIRCRAFT, 2017). CFD analysis is the modern method which is broad and rigorous. To determine aerodynamic features, USAF digital dot-com program is used.

In early stages of design, we cannot use Flight Testing because it is a very time-consuming process, expensive and aircraft is yet to be built (Ma, n.d.).

The full sized or scaled model prototype is required to perform the wind tunnel testing. It makes the method time consuming and expensive (Peter and Wenzel, 2017). It is majorly used by an aircraft manufactures on the new improvement projects.

Advantages of using flight simulation for aircraft design

The target of the flight reenactment show is to decide if a given airship is longitudinally steady and can be trimmed at a picked flight condition (Yun and Li, 2013). Along these lines, it is basic to show the flying machine segments that significantly affect the static and dynamic strength of an airship. Soundness is the inclination of a flying machine to focalize on the introductory harmony condition following a little unsettling influence from trim [5]. To set up trim harmony, a flat stabilizer (Hstab) edge and push are acclimated to get a lift constrain adequate to help the weight and a push power to adjust the drag at the coveted speed. The trim change is accordingly a critical outcome to be accomplished through the recreation display. The model manages the longitudinal trim as it were. Another basic undertaking is to decide the dynamic security of a given flying machine. This requires the arrangement of the longitudinal conditions of movement and finding both dynamic strength modes, the brief time frame pitching wavering and the phugoid. The conditions of movement can be comprehended by trimming the recreation show and a dynamic reaction can be acquired.

The recreation show is outlined in the graphical condition of Simulink in conjunction with Matlab. Simulink is the favored decision since the model can without much of a stretch be pictured (Jos van Schijndel, 2013). The model comprises of three fundamental pieces in particular Equations of Motion, Streamlined features, and Thrust squares. Each piece is characterized by an information and a yield. The usefulness of each square is actualized utilizing flight elements hypothesis (Awrejcewicz et al., 2014). Every one of the pieces is at that point connected to fabricate a flight reenactment demonstrate that can be hurry to watch flying machine conduct. The displaying procedure begins with the streamlined features of an airplane in which both the wing and tail commitments are displayed. The two models turn into a subsystem of the streamlined features piece. The push square is then developed which is connected with the condition of movement piece alongside the optimal design square. The coordinated piece or the best level reenactment is given in the figure below (Arabaci and Bilgin, 2012). The primary two contributions to the model are throttle from push piece and level stabilizer (Hstab) edge from the optimal design piece (Chen, 2013). The principle yields are pitch edge theta, pitch rate q, forward speed u and vertical speed w. Each piece of the best level reenactment demonstrate is clarified in whatever remains of this area.

Process of constructing a 3 DOF longitudinal flight simulation model

To run the simulation model, a Simulation Initialization Matlab script is required (Emar, 2016). This script stores the initialization parameters, universal and atmospheric constants, aircraft Geometry and thrust data. The initialization script is also needed to run another script called Trimming and Linearization which trims and linearizes the non-linear aircraft equations of Motion and gives the stability mode characteristics (Su, Yao and Du, 2014). The script also solves the linearized longitudinal equations of motions and outputs the A and B matrix. Each of the block has explained in the below clearly.

• Equations of motion model block

As shown in figure, The central model of simulation is the Equations of motion model. It is sometimes also called as aircraft dynamics model. The other models which are present in the figure will work to provide total forces and moment acting on aircraft to the equations of motion block. After working it will calculates the attitude (theta), pitch rate, forward velocity U and vertical velocity w. It also calculates the position coordinates of aircraft. It used Four selector blocks namely, output theta, pitch rate Q, U and w. These selector blocks will provide the trimmed input by enablling the Trimming and Linearization script to select the states. Moreover, the state-space variables are defined using selectors where the variables needed are U, w, q and theta. For calculating alpha, Mach number, dynamics pressure Q, velocity V and altitude from Xe, Ze, U and w another block called Atmosphere and Air Data is constructed. This block is also useful in creating a closed loop simulation model where alpha, Q, V and altitude are fed back to the model and help the model find the operating point to linearize the system.

• Aerodynamics model block

For Flight Simulation model, Aerodynamic model block is one of the important model. It solves the moments and aerodynamic forces acting on the aircraft about its center of gravity. These forces and moments are used to solve the equations of motion. The top level Aerodynamic Block is shown in Figure. The block requires five inputs such as angle of attack, dynamic pressure Q, velocity V, pitch rate q and horizontal stabilizer Hstab angle.

The block which is integrated with both aerodynamics and equation of motion blocks is Thrust block. It is used to calculate the thrust force that is added to Xaerob. Where as, the x-force in the body axes. The main input to the thrust block is the throttle setting with range of value between 0 and 1. The initial input value of the throttle setting for a given flight condition is  throttle_ini and it is stored in a constant block. Another input is the altitude to enable the block to calculate thrust at various altitudes. It is pertinent to discuss here the lack of thrust data for a given STOL aircraft. The simulation results has impacted by thrust. 

Methods for determining aircraft aerodynamics

Conclusion 

A fundamental 3-DoF longitudinal flight reenactment show has been worked to think about the conduct of an airship in this undertaking (Jin et al., 2013). The recreation show is exhaustive and can decide both the static and dynamic strength of an airship. The model likewise trims the plane movement and finds the trimmed information sources. The mass properties and geometric information of a nonspecific STOL airship were utilized to anticipate the streamlined conduct of aircraft. The recreation demonstrates comprised of three squares specifically Aerodynamic, Thrust and Equations of Movement pieces Asif and Iqbal, 2011). These squares are connected together to frame an incorporated longitudinal flight recreation display. Introduction content and Trimming and Linearization content were the two contents used to run the recreation display. The introduction content instated every one of the parameters required for reproduction and the other content linearized conditions of movement and gave the trimmed solution. Similarly, different outcomes when gotten for cases in which push, wing territory, and wing quarter harmony and Mach number were shifted (Journal of Defense Modeling & Application: Application, Methodology, Technology (JDMS), 2014). Both the static furthermore, dynamic solidness in each of the cases were additionally considered. It is apropos to say that the flight reenactment show outlined is very nonspecific in nature and can be utilized to reproduce the conduct of any flying machine (Kamiyama, 2012). In addition, the reenactment model can be reached out to serve any goal. It contains the basic components or frameworks of an airship that assume the most urgent part of any flight reenactment display.

References

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AERODYNAMIC ANALYSIS OF EAGLE WINGLETS ON AIRCRAFT. (2017). International Journal of Modern Trends in Engineering & Research, 4(5), pp.175-180.

Arabaci, H. and Bilgin, O. (2012). Squirrel Cage of Induction Motors Simulation via Simulink. International Journal of Modeling and Optimization, pp.324-327.

Asif, U. and Iqbal, J. (2011). MODELLING, CONTROL AND SIMULATION OF A SIX-DOF MOTION PLATFORM FOR A FLIGHT SIMULATOR. International Journal of Modelling and Simulation, 31(4).

Awrejcewicz, J., Szewczyk, R., Trojnacki, M. and Kaliczyn?ska, M. (2014). Mechatronics. Cham: Springer International Publishing.

Chen, X. (2013). A Study of Simulation Model of Doubly-Fed Motor Based on Matlab/Simulink. Advanced Materials Research, 816-817, pp.625-628.

Deiler, C. (2017). Aerodynamic Modeling, System Identification, and Analysis of Iced Aircraft Configurations. Journal of Aircraft, pp.1-17.

Emar, W. (2016). Analysis, modeling and simulation of step up converter using Matlab–Simulink and simplorer. International Journal of Modeling, Simulation, and Scientific Computing, 07(02), p.1650004.

Jin, G., Lu, L., Liang, J. and Zhu, X. (2013). Flight Control System for UAV Based on Simulink. Advanced Materials Research, 709, pp.662-666.

Journal of Defense Modeling & Application: Application, Methodology, Technology (JDMS). (2014). The Journal of Defense Modeling and Simulation: Applications, Methodology, Technology, 11(4), pp.431-431.

Ma, J. (n.d.). CICTP 2014.

Nebylov, A. (2013). Aerospace sensors. [New York, N.Y.]: Momentum Press.

Peter, T. and Wenzel, S. (2017). Coupled Simulation of Energy and Material Flow using Plant Simulation and MATLAB Simulink. SNE Simulation Notes Europe, 27(2), pp.105-113.

Su, L., Yao, H. and Du, J. (2014). Chaotic Analysis and Control of Longitudinal Flight Dynamics. Asian Journal of Control, 17(5), pp.1569-1579.

Yun, C. and Li, X. (2013). Aerodynamic Model Analysis and Flight Simulation Research of UAV Based on Simulink. Journal of Software Engineering and Applications, 06(02), pp.43-47.

Kamiyama, T. (2012). A Simulink to UML Transformation Tool for Embedded Control Software Design. International Journal of Modeling and Optimization, pp.197-201.