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  • Now let’s lot in detail at these different sensor types. Feel free to add your comments, experiences, and ideas as we chug through these. These sensors come in physical contact with something to work.
  • Pictures of feelers or whiskers.
  • Pictures of bumpers.
  • If you want to sense something at a short distance, there are choices that emit some sort of signal that produces reflections that they can see.
  • For greater distances at affordable prices, ultrasonic range sensors are a good choice.

Robotics Robotics Presentation Transcript

  • Computer vs. Human
    • Machine
    • Performs precisely defined tasks with speed and
    • accuracy
    • Not gifted with common sense
    • Human
    • Capable of understanding and reasoning
    • More likely to understand the results and
    • determine what to do next
    • Not gifted with complex computations
  • Humanlike Computer
    • The ideal hybrid
    • Continues without human intervention when
    • faced with unforeseen situations
    • Possesses or simulate the ability to reason
  • Robotics History
    • " Where did the word 'robot' come from?
    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
  • Robotics Terminology
    • 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
    • – welding
    • – inspection
    • – improving productivity
    • – Laboratory applications
    • Mobile Robots
    • – 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
  • Hardware- Robots
    • Robots are programmable computers designed to
    • perform a variety of tasks by moving parts, tools or
    • specialized devices.
    • • 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.
  • Robot Components
    • 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
    • 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.
    • Vision systems
  • 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?
    • Light
      • Presence, color, intensity, content (mod), direction
    • Sound
      • Presence, frequency, intensity, content (mod), direction
    • Heat
      • Temperature, wavelength, magnitude, direction
    • Chemicals
      • Presence, concentration, identity, etc.
    • Object Proximity
      • Presence/absence, distance, bearing, color, etc.
    • Physical orientation/attitude/position
      • 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
    • Whiskers
      • 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
    • Active (emitting)
      • 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
    • Active
      • 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.)
  • Effectors
    • Converts software commands into physical motion
    • Typically electrical motors or hydraulic/pneumatic cylinders
  • Actuators
    • Locomotion
    • Manipulation
  • Locomotion
    • Legs
    • Wheels
    • Other exotic means
  • Legs
    • 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
  • Manipulations
    • Degrees of freedom
      • independently controllable components of motion
    • Arms
      • 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
    • Grippers
      • 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
    • Electric
      • DC motor is the most common type used in mobile robots
      • stepper motors turn a certain amount / applied voltage
    • Pneumatic
      • operate by pumping compressed air through chambers
    • Hydraulic
      • 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
        • see http://www.sma-inc.com/SMAPaper.html
  • 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
    • Sense Think
    • Act
  • 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
  • Mobility Considerations
    • 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.
  • Different Degrees of freedom 1 DOF 2 DOF 3 DOF
    • “ 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
  • contd.
    • 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
    • machines .
  • 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
    • programming
  • Robotic Applications
    • – Space Missions
    • – Robots in the Antarctic
    • – Exploring Volcanoes
    • – Underwater Exploration
    • – Surgical assistant
    • ASSEMBLY- factories Parts handling
    • - Assembly
    • - Painting
    • - Surveillance
    • - 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
  • An example
    • 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: