1. Introduction to Robotics In the name of Allah

2. Introduction to Robotics o Leila Sharif o l_sharif@sharif.edul_sharif@sharif.edu o Lecture #2: The Big Picture & History

3. Introduction to Robotics Last time we saw:  Grading, projects and.. in this course  Humanoid and Industrial Robots  Difference of Robot & Simple Manipulator  Classification of Robots  Defining “robot”  Why “Robot”?  Robots may be used in ….  Robotics and Robot  Robotics is an interdisciplinary subject of …

4. Introduction to Robotics Lecture Outline  What makes a robot  Sensors, sensor space  State, state space  Action/behavior, effectors, action space  The spectrum of control  Reactive systems

5. Introduction to Robotics Advantages of Robots I  Increase productivity, safety, efficiency, quality and consistency of products  Without the need for life support, comfort or safety  No need lighting, air conditioning and noise protection  Work continuously without fatigue or boredom. Do not get mad, need no medical insurance and vacation

6. Introduction to Robotics Advantages of Robots II  More accurate than human  Robots and their accessories and sensors are beyond that of human  Robots can process multiple task simultaneously

7. Introduction to Robotics Disadvantages of Robots  Robots replace human worker create economic problem  Lack capability in response in emergencies, unless the situation is predicted and the response is included in the system  Have limited capabilities in (DOF, Dexterity, Sensors, Vision System, Real time response and..)  Are costly (Initial cost of equipment, Installation cost, Peripherals, Training, Programming)

8. Introduction to Robotics What Makes a Robot?  A robot consists of:  Manipulator  End effectors  Actuators  Sensors  Controller  Processor  Software  A robot is capable of:  acting autonomously  achieving goals

9. Introduction to Robotics Manipulator  Is the main body of the robot  Consist of the links, the joints and other structural elements

10. Introduction to Robotics End effectors  The part that is connected to the last joint (hand) of the robot to handle objects, make connections to other machines, or perform required task  They are specifically designed for a purpose:  Welding torch  Paint spray gun  Glue-laying device  ….

11. Introduction to Robotics Actuators  Are muscles of the manipulator  Common type of actuators: 1. Servomotors 2. Stepper motors 3. Pneumatic cylinders 4. Hydraulic cylinders 5. …

12. Introduction to Robotics Action/Actuation I  A robot acts through its actuators (e.g., motors), which typically drive effectors (e.g., wheels)  Robotic actuators are very different from biological ones, both are used for:  locomotion (moving around, going places)  manipulation (handling objects)

13. Introduction to Robotics Action/Actuation II  This divides robotics into two areas  mobile robotics  manipulator robotics

14. Introduction to Robotics Actuators and DOF  Mobile robots move around using wheels, tracks, or legs  Mobile robots typically move in 2D (but note that swimming and flying is 3D)  Manipulators are various robot arms  They can move from 1 to many D  Think of the dimensions as the robot’s degrees of freedom (DOF)

15. Introduction to Robotics Action v. Behavior  Behavior is what an external observer sees a robot doing.  Robots are programmed to display desired behavior.  Behavior is a result of a sequence of robot actions.  Observing behavior may not tell us much about the internal control of a robot. Control can be a black box.

16. Introduction to Robotics Autonomy  Autonomy is the ability to make one’s own decisions and act on them.  For robots, autonomy means the ability to sense and act on a given situation appropriately.  Autonomy can be:  complete (e.g., R2D2)  partial (e.g., tele-operated robots)

17. Introduction to Robotics Sensors: what can be sensed?  Depends on the sensors on the robot  The robot exists in its sensor space: all possible values of sensory readings  Also called perceptual space  Robot sensors are very different from biological ones  A roboticist has to try to imagine the world in the robot’s sensor space

18. Introduction to Robotics State: what can be known?  A sufficient description of the system  Can be:  Observable: robot always knows its state  Hidden/inaccessible/unobservable: robot never knows its state  Partially observable: the robot knows a part of its state  Discrete (e.g., up, down, blue, red)  Continuous (e.g., 3.765 mph)

19. Introduction to Robotics Types of State  External state: state of the world  Sensed using the robot’s sensors  E.g.: night, day, at-home, sleeping, sunny  Internal state: state of the robot  Sensed using internal sensors  Stored/remembered  E.g.: velocity, mood  The robot’s state is a combination of its external and internal state.

20. Introduction to Robotics State and Intelligence  State space: all possible states the system can be in  A challenge: sensors do not provide state!  How intelligent a robot appears is strongly dependent on how much it can sense about its environment and about itself.

21. Introduction to Robotics Internal Models  Internal state can be used to remember information about the world (e.g., remember paths to the goal, remember maps, remember friends v. enemies, etc.)  This is called a representation or an internal model.  Representations/models have a lot to do with how complex a controller is!

22. Introduction to Robotics Controller  Is similar to human’s cerebellum  Robot control refers to the way in which the sensing and action of a robot are coordinated.  The controller receives its data from the computer, controls the motions of the actuators and coordinates the motions with the sensory feedback information.

23. Introduction to Robotics Processor  Is the brain of robot  Is generally a computer  Calculates the motions of robot’s joints  Determines how much and how fast each joint must move to achieve the desired location and speed

24. Introduction to Robotics Software  Operating system  Robotic software Calculate the necessary motions of each joint based on the kinematic equations of robot.  Collection of routines and application programs for peripheral devices like vision or to perform the specific task

25. Introduction to Robotics Food for Thought  Are exo-skeletons robots?  Is HAL a robot?  Some intelligent Web agents are called “softbots”. Are they robots?  Most, if not all, of the robots you build in this class will use reactive control. What more is there?