TEXT 1С. Control systems

Control systems are combinations of components (electrical, me­chanical, thermal, or hydraulic) that act together to maintain actual system performance close to a desired set of performance specifica­tions. Open-loop control systems (e.g., automatic toasters and alarm clocks) are those in which the output has no effect on the input (Fig. 1).

Fig. 1. An open-loop control system 10

Closed-loop control systems (e.g., thermostats, engine governors, automotive cruise-control systems, and automatic tuning control cir­cuits) are those in which the output has an effect on the input in such a way as to maintain the desired output value (Fig. 2).

Fig. 2. A closed-loop control system

A closed-loop system includes some way to measure its output to sense changes so that corrective action can be taken. The speed with which a simple closed-loop control system moves to correct its output is described by its damping ratio and natural frequency. A system with a small damping ratio is characterized by overshooting the desired out­put before settling down. Systems with larger damping ratios do not overshoot the desired output, but respond more slowly.

A minute for rest

Who is a scientist? One who, consuming midnight oil in studies diligent* and slow, teaches himself, with painful toil** the things that other people know.

Last things first

Solutions to problems

are easy to find:

The problem's a great contribution.

What is truly an art

is to wring*** from your mind

a problem to fit a solution.

* diligent - прилежный, старательный **toil - тяжелый труд. ***to wring - вытаскивать, выуживать.

Essential Vocabulary

Accurate adj -точный attenuation n — уменьшение, затухание, ослабление bandwidth n - ширина полосы частот

closed-loop control system - система управления с обратной связью control system - система управления damping ratio - коэффициент затухания devise v — изобретать, придумывать differential equation - дифференциальное уравнение domain п — область, сфера

electronic feedback amplifier - усилитель с обратной связью emphasis п - выразительность, акцент fascinating adj - увлекательный feedback control - регулирование с обратной связью float п - поплавок

flyball governor - центробежный регулятор

foster v - поощрять, благоприятствовать

imperative adj - необходимый, насущный

impetus п - побудительная сила, толчок, стимул input п – вход

insight п - понимание

in terms of- с точки зрения; на языке; в терминах

open-loop control system - система управления без обратной связи output п - выход

performance п - действие, функционирование; работа; рабочие ха­рактеристики

root locus approach - метод корневого годографа simultaneously adv - одновременно spawn v - порождать, вызывать что-либо

transient oscillations - неустановившиеся колебания

trial-and-error approach - метод проб и ошибок unstable system - неустойчивая система variable п — переменная величина

UNIT 2

TASK 1. Read and translate the text. Be ready to give definitions to such concepts as "automation " and "productivity ".