Mechatronics and microprocessor

Outline •Introduction•System and design of system•Control, measurement and feed back

system•Open and closed loop system•Elements of closed loop system•Traditional vs mechatronics system•Sequential controllers•Programmable logic controller

Mechatronics•Mechatronics is the complete

integration of mechanical system with electrical, electronics and computer system

System •A system which consists of various

elements connected together to obtain the required output by giving a small input.

•A system can be represented with a block diagram.

input output

Modeling and modeling system•Modeling – behaviour of a real time

system represented in terms of methamatical equations.

•Modeling system – a model from which we can relate the input and output in terms of a mathematical equation.

Spring input outputForce extensio

n

control system •A group of devices or units or elements

which maintains the required output based on the preset or predefined level or quantity by controlling the input.

Fan input outputelectricit

yRequired

speedregulator

Open and closed-loop control systems•Open loop system

▫a system in which output is dependent on input.

Closed loop system▫a system in which input is dependent on

output.

Components of closed loop system•Comparison element• Error signal = reference value signal –

measured value signal

•Control element •Correction element•Process element•Measurement element

Control unit

Correction unit

Process unit

Comparison element Controlled

variable

Feed back unit/meas

uring device

Required value

Measurement system•A group of elements arranged in order to

measure the level of output in a control system.

•Measurement is quantity based. Ex displacement, temperature, velocity etc

•For accurate control of output.•Components

▫Sensors/ transducers▫Signal conditioner or amplifier▫Display

•Sensor – measures the output and generates an equivalent signal related to quantity.

•Signal conditioner – takes the signal from sensor manipulates it into a condition suitable for displaying

•Display system – output from signal conditioner is displayed.

sensor

Quantity measured

Signal condition

erDisplay

Signal related

to quantity measure

d

Suitable for

displaying

Value of quantity

sensorSignal

conditioner

Display Temperature

EMF

binary

Value of quantity

Feed back system•Feed back is a signal sent back to the

input from output.•Input varied is dependent on the feed

back signals got from output.

Heater Required

temperature

Room temperatur

e

Feedback signal of actual

temperature

Closed loop control system

• Controlled variable – room temperature• Reference value – the required room

temperature• Comparison element – the person comparing

measured value with required value• Error signal – the difference between measured

and required temperature• Control unit – the person• Correction unit – switch on the fire• Process – heating by the fire• Measuring device – a thermometer

Sequence and time based controllers•Sequence based controllers

▫These are controllers which are strictly ordered in a sequence driven.

▫Sequence is controlled by programming the microprocessor.

▫The operating sequence is called as a ‘program’.

Washing machine