Introduction Autoilot

AUTOPILOT AVIONICSSMF 3252 06/07-II

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TITLE : AUTOPILOT

OBJECTIVE : To investigate the autopilot system in aircraft

To know the function of autopilot

To know the characteristics of autopilot system

To know overall about the autopilot weather for

the military aircraft or commercial aircraft

BACKGROUND :

The autopilot is the system which furnishes the ‘muscles’ to

move the control, which in turn, position the aircraft in space. The

autopilot is not always a luxury. In military aircraft, which are often

extremely fast and maneuverable, pilot reaction time may be

inadequate. It is then a necessarily to damp out the fast oscillations

which may occur along any axis. Anyone who has flown with one of

these wonders for any length of time can appreciate their value in

decreasing pilot fatigue. They allow the pilot a break from continuous

hand flying, providing time to handle other cockpit duties. Helpful

when VFR, an autopilot really pays off when flying single pilot IFR or

when flying a large, complex aircraft.

Advanced avionics system main mission is to stabilize and

navigate the UAV without human operator intervention. This is

conducted with the integrated autopilot system, the low level control.

Besides this, telemetry communication, payload data signal processing

and transferring operations are handled within the avionics system. It

has the capability to transform all types of tactical mini range fixed

wing planes to fly without a need for a pilot.

DEFINATION OF AUTOPILOT :

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An autopilot is a mechanical, electrical, or hydraulic system

used to guide a vehicle without assistance from a human being. Most

people understand an autopilot to refer specifically to aircraft, but self-

steering gear for ships and boats is sometimes also called by this term.

RESEARCH ASPECT

Fundamental / principles of autopilot

Part of autopilot

Autopilot systems - Boeing 747 Flight Control Autopilot

Modern of autopilot

EDO – Aire Mitchell Systems – No followup Control

Systems

Fluidics – Smith SEP – 6 Autopilot

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http://en.wikipedia.org/wiki/Self-steering_gear

http://en.wikipedia.org/wiki/Self-steering_gear

http://en.wikipedia.org/wiki/Aircraft


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The first aircraft autopilot was developed by Sperry Corporation

in 1912. Lawrence Sperry is a Son of famous inventor Elmer Sperry was

demonstrated it two years later in 1914, and proved his credibility of

the invention, by flying the plane with his hands up.

The autopilot connected a gyroscopic attitude indicator and

magnetic compass to hydraulically operated rudder, elevator, and

ailerons. It permitted the aircraft to fly straight and level on a compass

course without a pilot's attention, thus covering more than 80% of the

pilot's total workload on a typical flight. This straight-and-level

autopilot is still the most common, least expensive and most trusted

type of autopilot. It also has the lowest pilot error, because it has the

simplest controls. In the early 1920s, the Standard Oil tanker J.A Moffet

became the first ship to use autopilot.

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http://en.wikipedia.org/wiki/Standard_Oil

http://en.wikipedia.org/wiki/Pilot_error

http://en.wikipedia.org/wiki/Aileron

http://en.wikipedia.org/wiki/Elevator_(aircraft)

http://en.wikipedia.org/wiki/Rudder

http://en.wikipedia.org/wiki/Compass

http://en.wikipedia.org/wiki/Attitude_indicator

http://en.wikipedia.org/wiki/Gyroscope

http://en.wikipedia.org/wiki/Elmer_Sperry

http://en.wikipedia.org/wiki/Lawrence_Sperry

http://en.wikipedia.org/wiki/Sperry_Corporation


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SERVOSYSTEM FUNDAMENTALS

Any servo system operates on the same basic principles

of autopilot. There is some kind of comparator unit at the input

through which a positive or negative input signal can be

compared with a feedback signal or opposite polarity. For

example the exact cancellation of the input will occur when the

output element, the rudder, elevator, or airplane itself is doing

exactly what the input signal commanded it to do. If place the

airplane in a turn, the feedback from the rudder will begin to

cancel the input when the rudder is turned far enough to start

the airplane turning, but complete cancellation will not take

place until the airplane is turning fast enough to make the

required turn in the required time. If the airplane tends to turn

too fast, the rate gyro signal changes polarity and slows down

the turn. For example yaw damping maybe selected by a switch

on the autopilot control panel.

AXIS AUTOPILOT

A block diagram for a 3 axis system used in the trident aircraft.

Note the use of the computer-amplifier before the servomotors and

examine the feedback loops. The system in the diagram also has a

mach (speed) hold system, which works like the cruise control on some

automobiles.

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APPROACH TO GLIDE PATH

The airplane is steered so that angles and are reduced to zero

at some distance d from the runway as designed by the transmitter.

The angular displacement can be converted into a distance l from

center by the equations l = d tan . The

l = d tan

The rate at which l is decreasing is given by

l = sin

Where equals approach velocity.

So the pilot knows is approaching the centerline. A panel

instrument will shows the deviation and can show to fast is

approaching the beam center. He knows that if he keeps his approach

rate at or below the present value, he will have a small transient, or

oscillation, about the beam center then crosses it. If he tries to

approach at a larger angle or faster rate, then he ill overshoot the

beam center and a large transient ill occur.

In addition to the panel, an aircraft ill have the selector type

panel. Approach to the localizer beam, the pilot ill push the button

marked VOR LOC to feed the input of the localizer receiver into the

autopilot for automatic control of the airplane laterally.

SEP-6 THEORY OF OPERATION

The SEP-6 autopilot is an electromechanical system

providing flight stabilization and maneuver control in the three

aircraft axes. Each computer has its own power supply, thus

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preventing a single power failure from rendering the whole

system inoperative. This has the advantages of allowing split-

axis operation as well as independent yaw damping.

The SEP-6 autopilot operates on a ‘rate-rate’ principle in

which control surface rates are mode proportional to aircraft

disturbance rate. Rate gyros in the three control axes are used

to detect aircraft disturbances and the resulting electrical

signals are amplified to drive the electromechanical

servomotors for short-term stabilization in pitch, roll and yaw.

In addition to short-term stabilization, attitudes changes

can be demanded to maneuver the aircraft in pitch and roll.

The maneuver commands are converted to rate commands

which are fed to the appropriate servomotor, together with

long-term stabilization signals derived from the attitude

reference system and various mode sensors. Any resultant

standing errors and long term data shifts are compensated by

integration.

The SEP-6 achieves all commanded functions by pitch and

roll axis control. This means that directional control is

maintained by ailerons throughout all flight maneuvers.

Provision is made to feed an aileron signal into yaw channel

for turn coordination. The pitch channel also provides signals

to control a separate trim servomotor which can be fitted to

the aircraft’s trim system. Autopilot operates in some detail

the pitch, roll and yaw channel.

PITCH CHANNEL

1. Function of pitch channel

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a) This channel provides pitch stabilization by operating the

aircraft controls and pitch trim pitch in response to

attitude and attitude rate signals.

2. Short term damping is derived from pitch and yaw rates,

modified by the roll angle to produce the true pitch rate in

the roll repeater module before being passed to the pitch

shaping module. Maneuver demands are obtained from in

inputs.

3. In the pitch shaping module, a pitch rate demand is

computed from the pitch attitude demand and added to the

true pitch rate signal, which has been phase advanced, it is

also added to the balance integrator signal and the servo

tachometer feedback signal. This combined signal is then

the gain scheduled to suit the particular flight configuration,

dependent on flap and airspeed conditions. The resultant

control signal, passed to the servomotor, also produces a

servo torque signal which is used to drive the trim

servomotor via the trim servo amplifier. It also provides a

trim signal to the pilot’s pitch trim indicator.

4. The glide coupling module computes a pitch demand signal

from deviation information derived from the instrument

landing system (ILS) radio receiver. A gain compensation

circuit reduces the gain as a function of time following glide

slope engagement. For category ll operation the glide signal

is further reduced as a function of radio altitude and is

supplement by a signal derived from pitch altitude. The

pitch “data chaser” produces a pitch error signal, which is

used as a pitch demand in the pitch attitude mode. The

balance integrator produces an error signal, based on pitch

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attitude demand to compensate for long-term data drift

within the channel.

ROLL CHANNEL

1. Function of roll channel is:

a) The roll channel stabilizes the aircraft about its roll axis

and in azimuth by controlling the ailerons in response to

the roll rate.

b) It is also used to control the aircraft azimuth when fed

with compass or radio deviation signals or manual control

demands.

2. Short term damping information is derived by multiplying

the yaw rate and the pitch angle and adding this to the

sensed roll rate to provide a true roll rate signal. The roll

channel contains a cutout to disengage it in case of

excessive roll rate or roll attitude.

3. The demands signal is compared with bank angle, and the

difference is fed as an error signal to the roll shaping

module, which operates in the same manner as the pitch

shaping module but with the demanded rill rate limited to 5

degree.

4. The control signal is amplified and passed to the

servomotor. The servo amplifier also produces a torque

signal to operate the pilot’s aileron trim indicator.

5. The heading data chaser produces a heading error signal

from the compass which is used as a bank demand when in

the heading mode.

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6. The localizer coupling module computes a bank demand

signal which is a function of the localizer deviation signal

and the rate of change of this signal. During the later stages

of ILS interception, yaw rate is added to the signal, and the

gain of the radio rate circuit is changed at glide slope

engagement to obtain optimum performance during the

final stages of the approach. The computation automatically

provides wind drift correction.

7. Maneuver demands are derived from the autopilot

controller, the heading data chaser, radio coupling modules,

or the HSI. These demands are selected from the mode

selector and having been limited in the roll switching

module to provide a demand of either 10 degree or 30

degree are passed to the roll shaping module and the

balance integrator, when the bank angle is less than 3

degree.

8. The VOR coupling module computes a bank demand signal

from the localizer coupling module and from a course error

signal from the HIS. In the later phases of interception, the

course error signal is washed out, thus allowing the aircraft

to take up a drift angle to offset crosswinds. The balance

integrator operates in the same manner as was described

for the pitch channel.

YAW CHANNEL

1. The yaw channel of the Smith SEP-6- autopilot is a self-

contained yaw damper system which is:

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a) Maintains aircraft yaw stability and assist the roll channel

during azimuth maneuvers so as to give full roll-yaw

coordination.

b) The yaw damper can be installed as a parallel or series

system, depending on the type of aircraft and the

principle of operation required.

2. The yaw channels are divided to two parts which is:

a) Parallel yaw damper

When the damper is in parallel, short term damping

information is derived from yaw rate shaping module to

produce a yaw rate demand signal which is added to the

servomotor feedback signal. This control signal is

amplifier in the servo amplifier, which drives the

servomotor. The amplifier also produces a true signal,

which operates the pilot’s yaw trim indicator. Aileron

position information is fed to the yaw shaping module

and backs off the shaped yaw rate term to insure that the

rudder control does not oppose entry into turns. Also a

lateral accelerometer produces a signal which acts as a

monitor for the suppression of sideslip.

b) Series yaw damper

When the damper is in series, the principle of operation is

the same as when it is in parallel, except that a lateral

accelerometer is not used, and the control signal is a

position demand signal to the linear actuator. Actuator

position information is fed back into the yaw shaping

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module in addition to rate feedback. This position signal

is also fed to the pilot’s yaw trim indicator.

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AERODYNAMICS OSCILLATIONS

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An aircraft in flight acts somewhat like a weathervane,

which tries to turn to point in a new direction as the wind changes.

The weathervane will oscillate, or swing back and forth, before finally

settling down to a new direction. If the wind is gusty, then the

oscillations continue indefinitely. This profile in the wind of a fan,

turning it sideways to the airflow. The release it and watch it oscillate

as it turns to point toward the airstreams.

The real aircraft has two oscillation periods which is a long

oscillation time as it veers back and forth across its flight path and the

short time oscillation as it changes its instantaneous heading. A pilot

can control the aircraft as long as oscillation time is longer than his

reaction time. Some fighter aircraft have very fast oscillation times

when the center of gravity approaches the center of wind pressure and

so autopilot is required in order for the pilot to handle the aircraft. The

autopilot controls the short period oscillation, and the pilot

controls the long period oscillation, or the flight path. Under an

aerodynamics oscillation there is damper.

DAMPER

The yaw damper is the part of the autopilot which

smoothes out the short-period yaw oscillations. The pilot will

have as its input some kind of reference, such as a gyroscope

heading signal, and the yaw damper ill tend to keep the

airplane pointed in the correct direction to follow this heading

with the smallest possible oscillation about the airplane’s

vertical, or yaw, axis .

The long term oscillation along the flight path, the

weaving back and forth along the flight line, is usually under

the control of the pilot in small aircraft. In large aircraft, it

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maybe autopilot controlled with a gyroscope reference, or it

may be under the autopilot and pilot’s control.

This kind of autopilot prevents short term oscillations by

sensing the airplane movement and immediately moving the

rudder to counteract them. An arrow a top the case indicates

the direction of turn for which an output voltage is produced.

Types of servomechanisms used in autopilot. The speed

range is 5-5000rpm. The tachometer gradient is 4.6 V per

1000rpm. The servo actuator at B is a product of control

technology, Inc. Its signal input is at 10V dc. The slew speed is

36°/sec. The unit is designed for operation with power sources of 115V

ac (400Hz) or 28V dc. At C is an Electro craft dc servo meter with a

heavy duty gear head. The power is 1/20 hp and the torque 3-200 in lb

for gearing ratios between 5:1 and 5000:1. The power input voltage is

28V. The tachometer gradient is a 4.6V per 1000rpm.

YAW DAMPING (SINGLE AXIS)

A dual channel system is incorporated to damp natural

yaw oscillations on channel driving the top rudder section, the other

the bottom. This redundancy insures safety in case of single failures or

local structural damage. The damping signal to the rudder is series

added to pilot controlled outputs, without causing rudder pedal

movement. A transient turn coordination output is also produced. Each

channel receives independently sensed information:

a) The variables sensed are roll altitude from the inertial navigation system.

b) True airspeed from the central air data computers.

c) Yaw rate from integral rate gyros.

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d) A ground only confidence checks tests the electronics and actuators.

e) Test response is shown on the rudder position indicator. Fault

isolation testing is also provided.

The following list states the capabilities:

Yaw damping (single axis)

Full time

For manual of power operated flying controls

Series or parallel systems as required

Rotary or linear actuator available

Pitch and roll autopilot (two axes) Pitch and roll stabilization

Manual maneuvering provided by controls by controls on

the autopilot controller

Heading lock

Autopilot with manometric locks and radio coupling (three

axes):

Yaw damper with pitch and roll autopilot gives

stabilization in three axes

Automatic pitch trim

Barometric sensors provide height and airspeed lock

facilities

Three channel-Engage and trim indication

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Preselect heading control

Variable beam intercept angle for operational flexibility

Automatic capture of VOR and ILS beams

Automatic wind drift correction

Optional facilities

Altitude preselect and vertical speed control

Mach lock

Category ll capability

The VOR is simply a radio beam transmitter which the airplane

autopilot can identify through its coupler. The fan markers are

transmitters located near the airport which transmit a vertical

fan shaped beam, when the airplane passes over them, the

pilots knows how far he is from the airport. Blue, amber and

white lights are lighted automatically on his panel as he

passes over the different markers. Note how complex the

approach may be if the airplane must be prevented from

landing right away and has to stay in a holding pattern.

AUTOPILOT-FLIGHT DIRECTOR

The autopilot function of the AF-FD provides:

a) Fully automatic attitude or path control, and

semiautomatic control via the flight controller

b) The flight directors display the required attitude change

in most autopilot modes and also when the autopilot is

off.

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The systems employs three identical computers each with

autopilot and flight director output. The latter output,

indicating the attitude change which the pilot or autopilot

must affect to properly control the airplane, can be displayed

on the attitude director indicators (ADI). Each pilot can

independently select any one of the computers.

For en route operation, either autopilot channel is used

alone. In the landing mode, both may be employed if their

outputs disagree beyond tolerance limits, a display warns the

pilot to consider switching to single channel mode or manual

control. The independence between channels including the fact

that each governs a different pitch and roll control

servomechanism gives the system capability for category ll

automatic landings.

The most significant improvement in operational

versatility has been made in pitch axis control, where altitude

preselection, airspeed hold, and altitude hold modes have

been made available both for autopilot and flight director. The

full listing of AP-FD functional capabilities is as follows:

No Mode Autopilot Flight Director

1. Pitch modes

Pitch Yes Yes

Pitch heel control Yes Yes

Altitude hold Yes Yes

Airspeed hold Yes Yes

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Altitude select Yes Yes

Turbulence Yes No

Go around No Yes

Vertical speed control

Yes Yes

2. Lateral modes

Heading hold Yes No

Turn knob control Yes No

Heading select Yes Yes

Inertial navigation Yes Yes

VOR/LOC navigation Yes Yes

Back Beam No Yes

3. Combined modes

Localizer capture Yes Yes

G/S capture and auto land with flare

Yes Yes

AVIATION AUTOPILOT CATEGORIES OF LANDING

Instrument aided landings are defined in categories by the ICAO.

These are dependent upon the required visibility level and the degree

to which the landing can be conducted automatically without input by

the pilot.

CAT I - This category permits pilots to land with a decision height

(where the pilot takes over from the autopilot) of 200 ft

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and a forward visibility of 2400 ft. Simplex autopilots are

sufficient.

CAT II - This category permits pilots to land with a decision height

of 100 ft and a forward visibility of 1200 ft. Autopilots have

a fail passive requirement.

CAT IIIa - A full blind landing capability on autopilot. Pilot assumes

control on touch down. The failure rate of the automatic

system must be better than 1 in 10 million.

CAT IIIb - As IIIa but with the addition of automatic roll out after

touchdown incorporated with the pilot taking control some

distance along the runway. Obviously for this category

some form of runway guidance system is needed.

CAT IIIc - As IIIb but with the inclusion of automatic taxi control

enabling runway to terminal without pilot intervention. No

current aircraft has this capability.

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Will examine now some complete autopilot systems. We

define a system as that complete aggregation of elements

which are necessary to cause the airplane to follow some

desired flight pattern.

The autopilot is an analog system using solid state

devices throughout. Direct-coupled circuits are used to

minimize the numbers of components, and all signal switching

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is solid state thus improving the reliability. The system utilizes

standard syncho transmissions and is therefore compatible

with many other systems

AUTOTHROTTLE

The auto throttle system of the AFCS maintains a

preselected airspeed during descent, approach and landing,

thus reducing pilot workload during these critical phases. Auto

throttle speed command, selected on the AP-FD glareshield

panel, is displayed on the pilot’s airspeed indicators. The

difference between the actual and commanded airspeeds

constitutes the error signal to a computer driving a servomotor

coupled by control cable to the throttles. The error signal is

displayed on each ADI. The flight mode annunciator provides

fault isolation testing. Operating any of four switches on the

throttle levers disengages the autothrottle.

An additional autothrottle function is provided. When the

autopilot is in autoland mode and flare altitude is reached, the

autopilot sends the autothrottle computer a signal which

initiates an automatic retarding of the throttles to their aft

stops.

AUTOMATIC THROTTLE –SEP-6

The automatic throttle system requires inputs from the

longitudinal accelerometer, the airspeed error signal, and

pitch attitude signal. These three signals are mixed in the

computer and used to control the servothrottle motors. The

computer also operates a warning flag signal on the pilot’s

display.

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The automatic throttle provides precise control of

airspeed during approach and terminal phases and automatic

closure (decrease) of fuel flow during flare out just before

touchdown.

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MINI AUTOPILOT V1.0.B

- Embbeded Power PC real time solution - Advanced system: Configurable to Fixed Wing and Rotor Wing Platforms- Waypoint navigation (GPS, D-GPS, INS)- Special fail safe navigation mode - Dynamic real time gains, limits etc. adjustments- Dual extended Kalman Filtering for precision navigation- Compressed digital image transferring - Autonomous Hand Launch, Autonomous flight, Autonomous belly landing, Autonomous parachute deployment capability - Manuel steering, Manuel control through secure digital link- Return home mode for communication loss, gps signal loss etc.- Communication relay mode (In Development) - Auto target coordinate detection through INS support- Fault tolerant embedded software

Weight (Sensors, Flight Control system, Radio Modem): 160 grams Dimensions: 12 cm x 9 cm x 4cm

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Features / Specifications:

Software:

Real time operating systemMultithreaded software (Stabilization, Navigation, Payload, Comm. Etc.)

Fault Tolerant

Fault Detection (Continuous Testing of the components)

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Real time flight data loading, gain adjustments and telemetry transfer

Digital Image Transferring

Hardware:

Advanced Integration: All functions in a single chip!3 Axis Gyros (300 deg/sec), Accelerometers (10g),

Magnetometers

Comm. Unit (>60 Miles LOS)

GPS Unit (4 Hz Update Rate)

Ultrasonic Range Finder Unit

Temp. Calibrated Pressure Ports

Digital Camera Unit

Voltage Regulator

13 Servo Output

Flight Control:

Full Autonomous Take Off And Landing (Catapult, Hand Launch, Wheel Take Off)Autonomous Cruise

Manuel Steering

Manuel Flight Mode

Return Home Option on Lost Communication

Advanced Attitude Estimation Techniques Through GPS

Physical:

Size: 180 mm * 125 mm * 55 mmWeight: 550 grams

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Features/Specifications:

A total integrated solution including 3 axis sensor suite, pressure ports, GPS, Ultrasonic Range Finder, Radio Modem, High Level Control PC, High Resolution CameraIndustrial PC Based Hardware

Real Time Operating System

Multithreaded software development

Autonomous Stabilization and Navigation

Real time flight data loading, gain adjustments and telemetry transfer

Home return in case of Lost Communications (Selective)

High Resolution Digital Image Transferring and Onboard storing (80 Gb)

LOS 90 km communication range (256 kbaud/sn.)-

Highly integrated, robust and secure solution for command,

control and monitoring. Microcontroller based control system handles

the management of data transfer of telemetry, payload and uplink

command. The operator interface runs on a Windows based PC system.

The system gives support for multi-UAV monitoring from a single

ground station thanks to the network enabling communication

systemsVV

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General Specifications and Features:

Ground Control System

Microcontroller based hardware

Real-time operating system environment

Multithreaded software architecture

Multi UAV command, control and monitoring support

Communications Management

HARDWARE IN THE LOOP SIMULATOR

Development of modern control, guidance and navigation

systems mostly depend on the control system and the modeling,

simulation, real-time testing of the system dynamics. Successfully

applied modeling and simulations can decrease the time required for

hardware prototype development in incredible amounts. Also, it

decreases the risks that might be encountered during testing and

system integration processes.

Simulation of the UAVs dynamic behavior in conditions that are

very close to real-flying environment is required very much for the

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development of the control system and the algorithms and also

evaluation of the vehicles performance under different conditions.

Conforming to these principles, flight control system algorithms and

guidance control system developed at Baykar Machine are initially

applied to the platform in the simulation environment and tests with

tuning continued till satisfactory results are taken.

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Modern autopilots generally divide to a several part which is:

A flight into taxi Take-off

Ascent

Level

Descent,

Approach and landing phases

Autopilots exist that automate all of these flight phases except

the taxiing. Landing on runway and controlling the aircraft on rollout

for example keeping it on the centre of the runway is CAT 3b landing,

used on the majority of major runways today. Landing, rollout and taxi

control to stand is CAT 3c. This is not usually used to date but may be

used in the future. An autopilot is often an integral component of a

Flight Management System.

Modern autopilots use computer software to control the aircraft.

The software reads the aircraft's current position, and controls a flight

control system to guide the aircraft. In such a system, besides classic

flight controls, many autopilots incorporate thrust control capabilities

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http://en.wikipedia.org/wiki/Software

http://en.wikipedia.org/wiki/Computer

http://en.wikipedia.org/wiki/Flight_Management_System


that can control throttles to optimize the air-speed, and move fuel to

different tanks to balance the aircraft in an optimal attitude in the air.

The autopilot reads its position and the aircraft's attitude from an

inertial guidance system. Inertial guidance systems accumulate errors

over time. They will incorporate error reduction systems such as the

carousel system that rotates once a minute so that any errors are

dissipated in different directions and have an overall nulling effect.

Error in gyroscopes is known as drift.

The six dimensions are usually roll, pitch, yaw, altitude, latitude

and longitude. Aircraft may fly routes that have a required

performance factor, therefore the amount of error or actual

performance factor must be monitored in order to fly those particular

routes. The longer the flight the more error accumulates within the

system.

Radio aids such as DME, DME updates and GPS may be used to

correct the aircraft position. Inertial reference units, i.e. gyroscopes,

are the basis of aircraft on board position determining, as GPS and

other radio update systems depend on a third party to supply

information. IRU's are completely self-contained and use gravity and

earth rotation to determine their initial position (earth rate). They then

measure acceleration to calculate where they are in relation to where

they were to start with. From acceleration one can get speed and from

speed one can get distance. As long as one knows the direction (from

accelerometers) the IRU's can determine where they are (software

dependent).

The Digital Autopilot is an all digital, self calibrating, two axis

Autopilot system designed specifically for the EFIS/One & EFIS/Lite. It

incorporates the latest in small, high torque mini DC motors, a high

quality aerospace grade gearbox, a high resolution position encoder

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http://en.wikipedia.org/wiki/GPS

http://en.wikipedia.org/wiki/Longitude

http://en.wikipedia.org/wiki/Latitude

http://en.wikipedia.org/wiki/Altitude

http://en.wikipedia.org/wiki/Flight_dynamics

http://en.wikipedia.org/wiki/Inertial_guidance_system


and a magnetic clutch all enclosed in single aircraft quality aluminum

housing.

Automatic Throttle

The automatic throttle system, inputs from the

longitudinal accelerometer, the airspeed error signal, and

pitch attitude signal. These three signals are mixed in the

computer and used to control the servo throttle motors. The

computer also operates a warning flag signal on the pilot’s

displays.

The automatic throttle provides precise control of

airspeed during approach and terminal phases and automatic

closure (decrease) of fuel flow during flare out just before

touchdown.

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Introduction Autoilot

Documents

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autopilot smf

autopilot page

level autopilot

autopilot weather

function of autopilot

defination of autopilot

integrated autopilot