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ROBOTIKA IT-012276
Dr. Tb. Maulana Kusuma, SKom., MEngSc.
http://mkusuma.staff.gunadarma.ac.id
P1 | Dasar-dasar Robotika
What is a Robot?
Electro-mechanical device.
Performs Various tasks.
May be human controlled or automated.
It finds it’s uses in all aspects of our life.
Robota
The term robot originates from the Czech word, robota, meaning “compulsory labor (or slave)”
From the play R.U.R. (Rossum’s Universal Robots) by Czech play writer Karel Capek in 1921.
Three Laws of Robotics In 1942, Issac Asimov, An American science fiction
writer, introduced the word “robotics” in his short story
Law 1: A robot may not injure a human being, or, through inaction, allow a human being to come to harm
Law 2: A robot must obey the orders given it by human beings except where such orders would conflict with the First Law
Law 3: A robot must protect its own existence as long as such protection does not conflict with the First or Second Law
G. Walter’s Robot – The first Robot
1948, 1953
A wheeled machine with motors
Photocells
Two vacuum tubes
Moved toward light if moderate intensity
Avoided bright light
What defines a robot?
Sense – a robot has to take in information about its environment
Plan – a robot has to use that information to make a decision
Act – a robot needs moving parts to carry out commands
Robot Classes
Manipulators: robotic arms. These are most commonly found in industrial settings.
Mobile Robots: unmanned vehicles capable of locomotion.
Hybrid Robots: mobile robots with manipulators.
Industrial Robots
Material Handling
Manipulator
Assembly
Manipulator
Spot Welding Manipulator
•Material handling
•Material transfer
•Machine loading and/or unloading
•Spot welding
•Continuous arc welding
•Spray coating
•Assembly
•Inspection
What Robots can do?
Basic Parts of a Robot
Mechanical system
Power supply system
Actuators
Sensory devices for feedback
Sensor Data processing unit
Control system
Mechanical System
The most basic and important part of the robot.
It comprises of chassis, motors, wheels and their placement.
This system decides the locomotion of the robot.
Wheeled Locomotion Systems
Differential drive
Car type drive
Skid steer drive
Synchronous drive
Pivot drive
Differential Drive
This is the most commonly used form of locomotion system used in robots as it’s the simplest and easiest to implement.
It has free moving wheel(s) in the front accompanied with a left and right wheel. The two wheels are driven by different motors.
Car Type Drive (Rack and Pinion)
It is characterized by a pair of driving wheels and a separate pair of steering wheels.
The translation and rotation are interlinked, hence this system faces severe path planning problem.
Skid Steer Drive
A close relative of the differential drive system.
It is mostly used in tracked machines e.g. tanks. Also finds application in some four / six wheeled robots
The left and right wheels are driven independently.
Steering is accomplished by actuating each side at a different rate or in a different direction, causing the wheels or tracks to slip, or skid, on the ground.
Synchronous Drive
As the name suggests, it uses synchronous rotation of its wheels to achieve motion & turns
It is made up of a system of motors. One set of which drive the wheels and the other set turns the wheels in a synchronous fashion
The two sets can be directly mechanically coupled as they always move in the same direction with same speed
Pivot Drive
• The most unique type of Locomotion system
• It is composed of a four wheeled chassis and a platform that can be raised or lowered
Pivot Drive (Cont’d)
The wheels are driven by a motor for translation motion in a straight line
For rotation one motor is needed to lower/raise the platform & another to rotate the chassis around the platform
This system can guarantee perfect straight line motion as well as accurate in – place turns to a desired heading
Power Supply System
Suitable power source is needed to run the robots.
Robots are most suitably powered by batteries.
The weight and energy capacity of the batteries may become the determinative factor of its performance.
Actuators
They convert the electrical energy into meaningful mechanical work
Mechanical output can be rotational or linear (straight line)
Motors provide rotational motion
Electromagnets provide linear motion
Motors are of various kinds
AC Motors : Not used much in robotics
Stepper Motors : For controlled rotation
DC Motors : Finds extensive general use
Servo Motors : DC motor with in built feedback & error compensation
Sensors
Analogous to human sensory organs
– Eyes, ears, nose, tongue, skin
Sensors help the robot knowing its surroundings better
Improves its actions and decision making ability
Provides feedback control
Examples
Light Dependent Resistor
Thermistor
Flame Sensor (ie. UVTron)
IR Photo Sensor
Proximity Sensor (ultrasonic, IR)
Vision (camera)
Line Following Robot
A line follower is a robot capable of tracking a line drawn on a surface
Optical sensors capture the line position at the front end of the robot
The robot is steered to keep it always over the line