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082-Engineering-Mathematics-Anthony-Croft-Robert-Davison-Martin-Hargreaves-James-Flint-Edisi-5-2017

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108 Chapter 2 Engineering functions

TechnicalComputingExercises2.4.6

1 Useatechnical computing language suchas

MATLAB ® to produce a plotofthe output of:

(a) afull wave rectifier circuit

(b) ahalfwave rectifier circuit

f (t)

2.4.7 Therampfunction

Theramp functionisdefined by

slope = c

f(t)=

{

ct t 0 cconstant

0 t<0

Figure2.46

Theramp function.

t

Its graph isshown inFigure 2.46.

Engineeringapplication2.17

Telescopedrivesignal

Inordertotrackthemotionofthestarslargetelescopesareusuallydrivenbyanelectricmotor.Thespeedofthismotoriscontrolledinorderthattheangularpositionof

thetelescopefollowsaspecifiedtrajectorywithtime.Thewholeassembly,including

telescope, gears, motor, controller and sensors, forms a position control system or

servo-system. This servo-system must be fed a signal corresponding to the desired

trajectoryofthesystem.OftenthistrajectoryisarampfunctionasillustratedinFigure2.47.Thedrivemotorisstartedattimet

=t 0

andthedesiredangularpositionof

the telescopeis θ.

u

Desired telescope

position

Drive motor started

t 0

t

Figure2.47

Tracking signal foratelescope.

2.4.8 Theunitstepfunction,u(t)

The unit stepfunctionisdefinedby

{ 1 t0

u(t) =

0 t<0

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