Robotics

Introduction Of Robotics

Robotics is the branch of technology that deals with the design, construction, operation, structural disposition, manufacture and application of robots.

Robotics is the sciences of electronics, engineering

 mechanics, and software.

Robot and Robotics technologies represented a practical applications of physics, computer science, engineering and mathematics.

What is a Robot ?• In practice it is usually an electro-mechanical

machine which is guided by computer and electronic programming.

• We can not exactly define that what robot is, but we can say that-– A robot can be electrical, mechanical or

electro-mechanical setup. – It can be programmable or non-

programmable.– It can be Manual or automated controlled.– It can be use to move parts and help human

beings.

three laws of robotics

1) A robot may not harm a human through action or inaction, allow a human to come to harm

2) A robot must obey the orders given by human beings, except when such orders conflict with the First Law

3) A robot must protect its own existence as long as it does not conflict with the First or Second Laws

Isaac Asimov popularized the term robotics. Asimov is a visionary who envisioned in the 1930’s the positronic brain for controlling robots. He invented the three laws of robotics:

A robot must have the following essential characteristics

Mobility: It possesses some form of mobility. Programmability: It can be programmed to

accomplish a large variety of tasks. After being programmed, it operates automatically.

Sensors: On or around the device that are able to sense the environment and give useful feedback to the device.

Mechanical capability: Enabling it to act on its environment rather than merely function as a data processing or computational device (a robot is a machine); and

Flexibility: It can operate using a range of programs and manipulates in a variety of ways.

Introduction of Embedded C and demo

programs Development process of AVR

projectsControl structures in CAlgorithms to be studiedAVR studio

Embedded system

• An Embedded system is combination of computer hardware and software, and perhaps additional mechanical or others parts, designed to perform a specific task.

• Example: microwave oven, AC etc

What is Embedded C?

Embedded C is nothing but a subset of C language which is compatible with certain microcontrollers.

Some features are added using header files like <avr/io.h>, <util/delay.h>.

scanf() and printf() are removed as the inputs are scanned from the sensors and outputs are given to the ports.

Control structures remain the same like if-statement, for loop, do-while etc.

Development process of Embedded C projects

• Write C programs in AVR Studio.• Compile them into a .hex file using the AVR-GCC compiler

(which integrates into AVR Studio).• Simulate the target AVR program and debug the code within

AVR Studio.• Program the actual chip using the AVRISP mkII USB device,

which is attached to our target board with a special 6-pin cable.

• Once programmed, the chip runs the program in your circuit.

If-statement

• Syntax: if( condition)

{ statement……. }else { statement…….. }

Program for if-statementInt a=4;Int b=5;If(a>b) printf(“ a is largest”);else printf(“ b is largest”);

Do- while statement• Syntax:Initial counterDo{ statement……. update statement}While(condition);

Program for do-whileInt a=4;Do { a++; } while(a>5);

For- statement • Syntax:For( initial counter; test condition; update stmt) { statement…….. statement……... }

• Program:for(int i=0;i<5;i++) sprintf(str, “Hello Robosapiens”);

What is a Microcontroller?

A microcontroller (sometimes abbreviated µC or MCU) is a small computer on a single IC containing a processor core, memory, and programmable input/output peripherals.

It is a decision making device used widely in embedded systems and all intelligent devices.

Basic Block Diagram of Microcontroller

Block Diagram to show the difference

Difference between Microcontroller and Microprocessor

Microcontroller has I/O ports, Memory, timers etc all integrated on chip itself

In Microprocessors, I/O ports, memory, timer etc are to be connected externally

What is a 8-bit microcontroller?

8-bit means it can process 8-bit data per clock cycle

It has 8-bit data bus

It can process 1byte of data at a time

What is AVR?

AVR is a modified Harvard architecture , 8-bit RISC single chip microcontroller.

It was developed in the year 1996 by Atmel Corporation.

What’s special about AVR?

They are fast.

AVR Microcontroller executes most of the instructions in single execution cycle.

AVRs are about 4 times faster than PIC.

They consume less power and can be operated in different power saving modes.

Creation of AVR Projects with AVR studio

Home screen of AVR STUDIO

Naming project as Line follower

Selecting Platform and Device

Coding window

Building the code

Build and Run the code

Select the HID boot flash icon

Click on to the find device.

Click on the browse button to browse the hex file.

Browse the file from your project folder , select the hex file and click open.

Finally click on to the write button to burn the hex file in the MCU.

Some common projects

are:-

WALL FOLLOWING

ROBOT USING I-BOT mini V3

Wall Follower using I-BOT is built using infrared based proximity sensor module.

The left module is used to detect the wall on the left side of the I-BOT.

The Left module is connected at approximately 45 degree to the board so as to detect the wall as shown next.

WALL FOLLOWING ROBOT USING I-BOT

mini V3

CASE 1 LS = ON CASE 2LS = OFF

WALL FOLLOWING

ROBOT USING I-BOT mini V3

LEFT SENSOR MOVEMENT ON TURN RIGHTOFF TURN LEFT

WALL FOLLOWING ROBOT LOGIC TABLE

LINE FOLLOWER

ROBOT USING I-BOT mini V3

A Line follower is an autonomous robot which follows either black line in white are or white line in black area. Robot must be able to detect particular line and keep following it.

BLOCK DIAGRAM

An array of sensor is used to detect the line. Based on the status of sensors, special circuit or controller decides the position of line and also the required direction of motion required to follow the line. Motor driver circuit is used to ON/OFF the LEFT/RIGHT motors of the robot to provide desired motion.

LINE FOLLOWER ROBOT

BLACK-LINE FOLLOWER ROBOT WHITE-LINE FOLLOWER ROBOT

types

Programme for line follower#include<avr/io.h>#include<delay/util.h>Void main(){DDRA=0X00;DDRB=0XFF;While(1){IF(PINA==0b00001001)

{PORTB=0b00001001;}IF(PINA==0b00000001){PORTB=0b00000001;}IF(PINA==0b00001000){PORTB=0b00001000;}IF(PINA==0b00000000){PORTB=0b0000000;}}}}}

BLACK-LINE FOLLOWER ROBOT

CASE 1Ls = ON

Rs = OFF

CASE 2Ls = OFF

Rs = ON

Ls = ON Rs = ON

CASE 3Ls = ON Rs = ON

CASE 4Ls = OFF

Rs = OFF

LEFT SENSOR RIGHT SENSOR MOVEMENT

ON ON FORWARD

OFF ON LEFT TURN

ON OFF RIGHT TURN

OFF OFF STOP

BLACK LINE FOLLOWER ROBOT LOGIC TABLE

WHITE-LINE FOLLOWER ROBOT

CASE 2Ls = ON

Rs = OFF

Ls = OFF Rs = OFF

CASE 3Ls = OFF Rs = ON

CASE 4Ls = OFF

Rs = OFF

CASE 1Ls = OFF

Rs = OFF

LEFT SENSOR RIGHT SENSOR MOVEMENT

ON ON STOP

OFF ON RIGHT TURN

ON OFF LEFT TURN

OFF OFF FORWARD

WHITE LINE FOLLOWER ROBOT LOGIC TABLE

• Large organisations and companies reap many benefits from robotic technologies because:

• Robots are less expensive than paying human workers over the long run and robots are not prone to injure themselves.

Current Robotic Technologies

• Robots are used internationally by Police, Army, Navy and Air force organisations

• Robotic technology is used to deal with hazardous situations such as dealing with suspicious packages, riots and for the collection of foreign intelligence

• NASA scientists use robotic technologies (Mars Explorer) to explore other planets

Robots are currently used for situations where human safety is an issue

Industrial Application

• Repetitive tasks

• High speed

• High precision movements

• Pre-planned trajectories and task policies

• Automated and no human interference required

SENSORS

WHAT IS A SENSOR….?• A sensor is a device that measures a physical

quantity and converts it into a signal which can be read by an observer or by an instrument.

• Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps which dim or brighten by touching the base.

• Applications include cars, machines, aerospace, medicine, manufacturing and robotics.

TYPES OF SENSORS

• IR SENSOR

• SOUND SENSOR

• TEMPERATURE SENSOR

IR SENSOR

WORKING• IR sensor works on the principle of emitting IR

rays and receiving the reflected ray by a receiver (Photo Diode).

• IR source (LED) is used in forward bias.• IR Receiver (Photodiode) is used in reverse

bias.

VOLTAGE COMPARATOR

• A Comparator is a device which compares two voltages or currents and switches its output to indicate which is larger.

• Comparator is an Op-amp.

LIGHT Sensor Circuit

TEMPERATURE SENSOR

TIMER 555 IC

The 555 Timer IC is an integrated circuit (chip) implementing a variety of timer and multivibrator applications.

OPERATING MODES

• MONOSTABLE MODE

• BISTABLE MODE

• ASTABLE MODE

Monostable mode• In this mode, the 555 functions as a "one-

shot"

• Applications include timers, missing pulse detection, bouncefree switches, touch switches, frequency divider, capacitance measurement, pulse-width modulation (PWM) etc

CIRCUIT DIAGRAM IN MONOSTABLE MODE

Contd....• The pulse begins when the 555 timer receives a

trigger signal. • The width of the pulse is determined by the time

constant of an RC network, which consists of a capacitor (C1) and a resistor (R1).

• The pulse width can be lengthened or shortened to the need of the specific application by adjusting the values of R and C.

T = 1.1 X R1 X C1

Pictorial representation

Bistable Mode

o In bistable mode, the 555 timer acts as a basic flip-flop.o The trigger and reset inputs (pins 2 and 4 respectively on a

555) are held high via pull-up resisters while the threshold input (pin 6) is simply grounded.

o Thus configured, pulling the trigger momentarily to ground acts as a 'set' and transitions the output pin (pin 3) to Vcc (high state).

o Pulling the reset input to ground acts as a 'reset' and transitions the output pin to ground (low state).

o No capacitors are required in a bistable configurationo Pin 8 (Vcc) is, of course, tied to Vcc while pin 1 (Gnd) is

grounded.o Pins 5 and 7 (control and discharge) are left floating.

Astable mode

• In Astable mode, the '555 timer ' puts out a continuous stream of rectangular pulses having a specified frequency.

• Resistor R1 is connected between VCC and the discharge pin (pin 7) and another resistor (R2) is connected between the discharge pin (pin 7), and the trigger (pin 2) and threshold (pin 6) pins that share a common node.

• Hence the capacitor is charged through R1 and R2, and discharged only through R2.

Contd....• In the above circuit we are triggering the 555

timer by applying voltage produced by sound.• This voltage when generated pass through the

capacitor which works as a filter.• This filtered voltage is then fed to transistor

which is inverting the voltage and also amplifying it.

• And hence creating a negative triggering pulse.