In fact, the term "robot" was first used in 1920 in a play called "R.U.R." Or "Rossum's universal robots" by the Czech writer Karel Capek. The plot was simple: man makes robot then robot kills man! Many movies that followed continued to show robots as harmful, menacing machines
Robot - Mechanical device that performs human tasks, either automatically or by remote control. (From the Czech word robota.)
Robotics - Study and application of robot technology.
Telerobotics - Robot that is operated remotely.
Definitions What is the definition of a ‘robot’?
“ A reprogrammable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through various programmed motions for the performance of a variety of tasks ." Robot Institute of America, 1979 “ Force through intelligence .” “ Where AI (Artificial Intelligence) meet the real world.” “ An automatic device that performs functions normally ascribed to humans or a machine in the form of a human.” Webster’s Dictionary
Law Of Robotics
Asimov proposed three “ Laws of Robotics ”
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 orders given to it by human beings, except where such orders would conflict with a higher order law
Law 3: A robot must protect its own existence as long as such protection does not conflict with a higher order law
Types of Robots
Industrial Robots –
– materials handling
– improving productivity
– Laboratory applications
– Robots that move around on legs, tracks or wheels.
In 1979 a nuclear accident in the USA caused a leak of radioactive material
Led to production of special robot –teleoperator to handle the radioactive material
• Educational Robots – robotic kits are used
extensively in education. Examples are Robolab and Lego and RoboCup Soccer
Domestic Robots – 2 types – those designed to perform household tasks and modern toys which are programmed to do things like talking, walking and dancing
Robots are programmable computers designed to
perform a variety of tasks by moving parts, tools or
• Non- adaptive robots - no way of sensing the environment,
so do the job regardless of any environmental factors
• Adaptive Robots - get feedback from a sensor to alter the
operation of the device.
Robots can also be classified according to whether they are
stationary or mobile. Mobile robots are free to move around,
but stationary robots remain in 1 place but have arms that move.
1. Manipulator or Rover : Main body of robot
(Links, Joints, other structural element of the robot)
2. End Effecter : The part that is connected to the last joint hand)
of a manipulator
3. Actuators : Muscles of the manipulators (servomotor, stepper motor, pneumatic and hydraulic cylinder)
4. Sensors : To collect information about the internal state of the
robot or To communicate with the outside environment
5. Controller : Similar to cerebellum. It controls and coordinates the
motion of the actuators.
6. Processor : The brain of the robot. It calculates the motions and
the velocity of the robot’s joints, etc.
7. Software : Operating system, robotic software and
the collection of routines.
Sensors that tell the robot position/change of joints: odometers, speedometers, etc.
Force sensing: Enables compliant motion--robot just maintains contact with object
Sonar: Send out sound waves and measure how long it takes for it to be reflected back. Good for obstacle avoidance.
Why Do Robots Need Sensors?
Provides “awareness” of surroundings
What’s ahead, around, “out there”?
Allows interaction with environment
Robot lawn mower can “see” cut grass
Protection & Self-Preservation
Safety, Damage Prevention, Stairwell sensor
Gives the robot capability to goal-seek
Find colorful objects, seek goals
Makes robots “interesting”
Sensors - What Can Be Sensed?
Presence, color, intensity, content (mod), direction
Presence, frequency, intensity, content (mod), direction
Temperature, wavelength, magnitude, direction
Presence, concentration, identity, etc.
Presence/absence, distance, bearing, color, etc.
Magnitude, pitch, roll, yaw, coordinates, etc
Sensors - What Can Be Sensed?
Magnetic & Electric Fields
Presence, magnitude, orientation, content (mod)
Resistance (electrical, indirectly via V/I)
Presence, magnitude, etc.
Capacitance (via excitation/oscillation)
Presence, magnitude, etc.
Inductance (via excitation/oscillation)
Presence, magnitude, etc.
What Sensors Are Out There?
Visual – Cameras & Arrays (Active & Passive)
Color Sensors (Active & Passive)
Magnetic (Active & Passive)
Orientation (Pitch & Roll)
GPS (location, altitude)
Compass (orientation, bearing)
Voltage – Electric Field Sensors
Current – Magnetic Field Sensors
Chemical – Smoke Detectors, Gas Sensors
What Sensors Are Out There?
Feelers (Whiskers, Bumpers) – Mechanical
Photoelectric (Visible) – Active & Passive
Infrared (light) – Active & Passive
Ultrasonic (sound) – Active & Passive
Sonic – Active & Passive
Resistive/Capacitive/Inductive – Active & Passive
Sensors – Feelers
Piano wire suspended through conductive “hoop”
Deflection causes contact with “hoop”
Springy wire that touches studs when deflected
Reaches beyond robot a few inches
Simple, cheap, binary output
Bumpers & Guards
Impact/Collision sensor, senses pressure/contact
Microswitches & wires or framework that moves
Simple, cheap, binary output, easy to read
Feelers - Whiskers
Feelers - Bumpers & Guards From Kevin Ross’s “Getting Started Article (SRS Website)
Sensors – IR
Oscillator generates IR reflections off objects
Filtered receiver looks for “reflections”
Pulses may be encoded for better discrimination
Typically frequencies around 40KHz
Doesn’t work well with dark, flat colored objects
Passive (sensor only)
Pyro-electric (heat sensor)
Look for IR emissions from people & animals
Used in security systems & motion detectors
Sensors – Ultrasonic
Emit pulses & listen for echos
Times round trip sound travel (~1ft/mS)
Reaches far fairly beyond robot (inches to 30-50’)
Relatively simple, not cheap, analog output
Directional; not everything reflects sound well
Passive (listens only)
Sensor listens for ultrasonic sounds
Electronics may translate frequency or modulation
Software may perform signal analysis (FFTs, etc.)
Converts software commands into physical motion
Typically electrical motors or hydraulic/pneumatic cylinders
Other exotic means
Two legs seems the most obvious configuration
but in fact balance is an incredibly difficult problem
e.g. the Honda Humanoid Project
need knees, ankles and hips in order to move around
two legs are inherently unstable: difficult to stand still
Six legs are much easier to balance and move
stable when not moving
can work with simple cams and rigid legs
Brooks et al. (1989) evolved the walking Genghis robot
Degrees of freedom
independently controllable components of motion
convenient method to allow full movement in 3D
more often used in fixed robots due to power & weight
even more difficult to control!
due to extra degrees of freedom
may be very simple (two rigid arms) to pick up objects
may be complex device with fingers on end of an arm
probably need feedback to control grip force
Manipulation Actuator Types
DC motor is the most common type used in mobile robots
stepper motors turn a certain amount / applied voltage
operate by pumping compressed air through chambers
pump pressurized oil: usually too heavy, dirty and expensive to be used on mobile robots
Shape memory alloys (SMA’s)
metallic alloys that deform under heat and then return to their previous shape: used for artificial muscles
Measuring Motion: Odometers
If wheels are being used, then distance traveled can be calculated by measuring number of turns
dead-reckoning or odometry is the name given to the direct measure of distance (for navigation)
Motor speed and timing are very inaccurate
measuring the number of wheel rotations is better
shaft encoders , or rotation sensors , measure this
Different types & technologies of shaft encoder
The robot control loop
Output information Move, Speech Text, Visuals Wheels Legs Arms Tracks Speech, Vision Acceleration, Temperature Position ,Distance Touch, Force Magnetic field ,Light Sound ,Position Task planning Plan Classification Learn Process data Path planning Motion planning Sense Think Act
A number of issues impact selection of drive
Maneuverability - ability to alter direction/speed
Controllability - practical and not too complex traction sufficient to minimize slippage
climbing ability - traversal of minor discontinuities, slope rate, surface type, terrain
stability - must not fall over!
efficiency - power consumption reasonable
maintenance - easy to maintain, reliable
environmental impact - does not do damage
navigation - accuracy of dead-reckoning
Degrees of Freedom
Degrees of freedom - Each plane in which a robot can maneuver.
ROTATE BASE OF ARM
PIVOT BASE OF ARM
WRIST UP AND DOWN
WRIST LEFT AND RIGHT
Different Degrees of freedom 1 DOF 2 DOF 3 DOF
HOW ROBOTS WORK
“ The inspiration for the design of a robot manipulator is the human arm, but with some differences. For example, a robot arm can extend by telescoping—that is, by sliding cylindrical sections one over another to lengthen the arm. Robot arms also can be constructed so that they bend like an elephant trunk. Grippers, or end effectors, are designed to mimic the function and structure of the human hand. Many robots are equipped with special purpose grippers to grasp particular devices such as a rack of test tubes or an arc-welder. The joints of a robotic arm are usually driven by electric motors. In most robots, the gripper is moved from one position to another, changing its orientation. A computer calculates the joint angles needed to move the gripper to the desired position in a process known as inverse kinematics. Some multi-jointed arms are equipped with servo, or feedback, controllers that receive input from a computer. Each joint in the arm has a device to measure its angle and send that value to the controller
If the actual angle of the arm does not equal the computed angle for the desired position, the servo controller moves the joint until the arm's angle matches the computed angle. Controllers and associated computers also must process sensor information collected from cameras that locate objects to be grasped, or they must touch sensors on grippers that regulate the grasping force. Any robot designed to move in an unstructured or unknown environment will require multiple sensors and controls, such as ultrasonic or infrared sensors, to avoid obstacles. Robots, such as the National Aeronautics and Space Administration (NASA) planetary rovers, require a multitude of sensors and powerful onboard computers to process the complex information that allows them mobility. This is particularly true for robots designed to work in close proximity with human beings, such as robots that assist persons with disabilities and robots that deliver meals in a hospital. Safety must be integral to the design of human service robots.”
First Commercial Robot
• After the 1950’s the first commercial robot
nicknamed the ‘Unimate‘, was created.
• The first Unimate was installed at a General
Motors plant to work with heated die-casting
The Purpose of Robots
- Repetitive tasks that robots can do 24/7.
- Robots never get sick or need time off.
- Robots can do tasks considered too dangerous for humans .
- Robots can operate equipment to much higher precision than humans.
-May be cheaper over the long term
- May be able to perform tasks that are impossible for humans
Robots are also used for the following reasons
The Purpose of Robots
• Robots are also used for the following tasks:
• Dirty Tasks
• Repetitive tasks
• Dangerous tasks
• Impossible tasks
• Robots assisting the handicapped
Advantages VS. Disadvantages of Robots
♦ Robots increase productivity, safety, efficiency, quality, and
consistency of products.
♦ Robots can work in hazardous environments without the need.
♦ Robots need no environmental comfort.
♦ Robots work continuously without experiencing fatigue of problem.
♦ Robots have repeatable precision at all times.
♦ Robots can be much more accurate than human.
♦ Robots replace human workers creating economic problems.
♦ Robots can process multiple stimuli or tasks simultaneously.
♦ Robots lack capability to respond in emergencies.
♦ Robots, although superior in certain senses, have limited
capabilities in Degree of freedom, Dexterity, Sensors, Vision
system, real time response.
♦ Robots are costly, due to Initial cost of equipment, Installation
costs, Need for Peripherals, Need for training, Need for
– Space Missions
– Robots in the Antarctic
– Exploring Volcanoes
– Underwater Exploration
– Surgical assistant
ASSEMBLY- factories Parts handling
- Security (bomb disposal … really telecherics
rather than robotics)
- Home help (grass cutting, nursing)
Neural networks and AI
After initial training - neural network may be used to control robot platform. It can learn by itself reacting to real world objects
In neural networks we have two subjects: “knowledge” and “learning”. This means that intelligent systems has some knowledge, or so called experience and ability to learn and improve
In general neural network is a set of interconnected elements where each of them has their own input signals and outputs some resulting signal. For instance simple robot platform: