SUBMITTED BY PRAMOD H SDEPT OF MECHATRONICSJSS POLYTECHNIC NANJANGUD

HISTORY OF FBW

Electronic signaling of the control surfaces was tested in the 1950s.

This replaced long runs of mechanical and hydraulic connections with electrical ones.

The first digital fly-by-wire aircraft to take to the air (in 1972) was an  modified electronically

The term "fly-by-wire" implies a purely electrically-

signaled control system. It is used in the general sense of computer-configured

controls. where a computer system is interposed between the

operator and the final control actuators or surfaces. This modifies the manual inputs of the pilot in

accordance with control parameters.

Fly-By-Wire was designed so that the pilot moves his

controls that provided electrical inputs into a

computer.

The computer then uses information from other inputs

and then calculates the proper control changes.

This command is transmitted by WIRE to an actuator

or a servo back to the wing/tail which moves the

control surface.

INNER VIEW OF AN FBW

Fly-by-wire control systems allow aircraft

computers to perform tasks without pilot input.

Automatic stability systems operate in this

way. Gyroscopes fitted with sensors are mounted

in an aircraft to sense movement changes in

the pitch, roll and yaw axes. Any movement (from

straight and level flight)

CONTROLLER

SYSTEM

SENSOR

REFERENCE+

-

MEASURED ERROR

MEASURED OUTPUT

SYSTEM INPUT

SYSTEMOUTPUT

THERE ARE TWO TYPES OF SYSTEMS IN FBW THEY ARE

ANALOG SYSTEM

DIGITAL SYSTEM

Fly-by-wire replace hydromechanical or electromechanical flight control systems with electronic circuits.

The control mechanisms in the cockpit now

operate signal transducers, which in turn generate the appropriate electronic commands.

These are next processed by an electronic controller with an analog signal.

A digital fly-by-wire flight control system is similar to its analog counterpart.

The signal processing is done by digital computers and the pilot literally can "fly-via-computer". It increases the flexibility of the flight control system.

The digital computers can receive input from any aircraft sensor.

This also increases the electronic stability, because the system is less dependent on the values.

This eliminates mechanical contacts.

The mechanical contacts are replaced by wires

Due to the elimination of the mechanical contacts wear and tear is reduced.

The control system used in this type is far more intelligent then the conventional system.

The F-8 digital fly-by-wire program served as the springboard for DFBW technology to be used in both military and civilian aircraft.

satellite manufacturers also routinely use the technology in their vehicles and spacecraft.

Space Shuttle

Several unmanned aerial vehicles (UAVs)

APPLICATIONS OF DIGITAL FBW

Analog system Digital system

1) Accuracy low 1) Accuracy high

2) Circuit Complication 2) circuit is simplified

3) Calibration is tough 3) calibration is easy

This system has less or no drawbacks. But some of the

people argue that the system containing software program is

never free of troubles rather how many times it is been

checked or serviced. Rather then software the failures of

sensors may also be trouble. But this problems are not

considered because the sensors are highly precise and

developed for these types of system.

ADVANCED AEROPLANES WHICH ARE BASED ON FBW

F-22 RAPTOR

MI-35

TYPHOON

SUKHOI-47

Fly-by-wireless

Power-by-wire

Fly-by-optics

Higher accuracy

Due to the elimination of the mechanical contacts wear and tear is reduced.

The control system used in this type is far more intelligent then the conventional system.