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UCK441E FLIGHT STABILITY AND CONTROL

CLASS PROJECT

Due 10 January 2016 at 18:00

Now that based on your student number’s last digit, you are assigned an aircraft from Nelson Appendix B at a particular flight condition, here is the Design Challenge Class Project:

1. PART A : Understanding Your Aircraft's Behavior (5pts)

Using the stability coefficients given for your aircraft, program the longitudinal and lateral equations

of motion. For both of these dynamics (i.e. longitudinal and lateral)

a) Find the natural frequencies using both the general set of equations and approximations (i.e. such

as short-period or dutch-roll mode approximation). Compare both of the solutions and provide

insight to why the solutions are different or close to each other.

b) Identify and categorize the class and flight phase of your aircraft. Based on the flying handling

qualities, rate your aircraft's level. At this level, we assume that there is no active any stability and

flight augmentation control system design. If you are excited, you can try to give a pseudo pilot

Cooper-Harper scale rating also.

2. PART B : Stability Augmentation System Design (5pts+ 3pts Bonus)

Taking the flying handling qualities and your gut judgment as the norm, improve or enhance flying

characteristics of your aircraft:

a) Design a longitudinal stability augmentation system for the short-period mode. You can do this in

a straightforward fashion using the rate and gain feedback techniques and examples shown in

class.

b) Design a lateral stability augmentation system for the dutch-roll mode. You can do this in a

straightforward fashion using the rate and gain feedback techniques and examples shown in class.

c) BONUS (3pt.): To get the bonus, include the dynamics of the actuators (i.e. the servo dynamics)

on your controller synthesis and while evaluating the response of your aircraft. For all the systems

expect thrust assume that the dynamics look like this : for example;

for the elevator it can 𝛿𝑒_𝑜𝑢𝑡𝑝𝑢𝑡

𝛿𝑒_𝑖𝑛𝑝𝑢𝑡=

8

𝑠+8 and for the throttle (i.e. the engine dynamics) assume that

it looks something like 𝛿𝑡_𝑜𝑢𝑡𝑝𝑢𝑡

𝛿𝑡_𝑖𝑛𝑝𝑢𝑡=

1

𝑠+1.

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3. PART C : Autopilot Mode System Design (8 pts)

To have these extra points directly affecting your grade, review Chapter 8 of Nelson one more time

and design these autopilot modes including the servo dynamics:

a) Either a pitch displacement autopilot or roll attitude autopilot. (2 Pts)

b) Either an altitude hold control system or velocity hold control system. (2 Pts)

c) Design a coordinated turn control system (See Fig. 1) for the aircraft by using root-locus method.

Plot the response of the closed-loop system and rudder control signal for 𝛿𝑎 = +2° pilot step

input. (2 Pts)

Figure 1: Block diagram of system using sideslip to obtain coordination.

d) After you designed the linear control systems, evaluate the amplitude of the control signals

which are fed to the aircraft control surface actuators. Add saturations to the control systems as

mentioned below. Plot the control signal of the closed-loop systems. If necessary, re-design the

control systems. (1 Pts)

- Elevator deflection limit, 𝛿𝑒 = ±30°

- Aileron deflection limit, 𝛿𝑎 = ±30°

- Rudder deflection limit, 𝛿𝑟 = ±30°

- Select and apply an appropriate control signal limit for the velocity hold autopilot of your

aircraft.

e) Obtain the closed-loop responses and control signals of the systems that you chose in 3a and

3b for initial conditions given below: (1 Pts)

- For pitch displacement control system, Δ𝜃0 = 5°

- For roll attitude control system, Δ𝜙0 = 5°

- For altitude hold control system, Δℎ0 = −5 𝑚

- For velocity hold control system, Δ𝑉0 = −20 𝑚/𝑠

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Allocation of HW AIRCRAFT

Your student number last digit Aircraft Name Flight Condition

1 Navion M=0.158

2 F-104 M=0.257

3 F-104 M=1.8

4 A-4D M=0.4

5 A-4D M=0.8

6 JetStar M=0.2

7 JetStar M=0.8

8 Convair880 M=0.25

9 Convair880 M=0.8

0 Boeing 747 M=0.9

Important Note

Please note that we provide the below parameters for your associated aircraft. These parameters will be

sufficient for you to do many of the designs. Given your design approach, there can be needs for finding

or approximating stability or control derivatives. In these cases, we expect you to do literature search to

find these parameters, or approximate these parameters through additional computation or just by

making engineering and logical approximations. In this case, do not forget to reference and note the details

of your approximation and thinking.

Include plots, figures, equations and your code to support your results!!! If you do not provide it you will

not get any marks!!!! Cheating at any part (including replicating code,etc…) means automatic zero!!!

If you cannot find some of the aerodynamic coefficients of the assigned aircraft, you can use additional

reference book which is given below.

Napolitano M. R., “Aircraft Dynamics: From Modeling to Simulation”, John Wiley & Sons, 2012

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CONTROL AND STABILITY DERIVATIVES OF THE AIRCRAFTS

1) NAVION

5

2) F-104-A FIGHTER

6

3) A-4D FIGHTER

7

4) JETSTAR BUSSINESS JET

8

5) CONVAIR 880

9

6) BOEING 747