In the name of Allah Robotics Sharif Introduction

In the name of Allah Robotics Sharif

Introduction to Robotics o Leila Sharif o l_sharif@sharif. edu o. Lecture #2: The Big Picture (Robot Components) Robotics Sharif

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

What Makes a Robot? q A robot consists of: q q q q Manipulator End effectors Actuators Sensors Controller Processor Software q A robot is capable of: q acting autonomously q achieving goals Robotics Sharif

Manipulator q. Is the main body of the robot q. Consist of the links, the joints and other structural elements Robotics Sharif

End effectors q 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 q They are specifically designed for a purpose: q q Robotics Welding torch Paint spray gun Glue-laying device …. Sharif

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

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

Action/Actuation II q. This divides robotics into two areas q mobile robotics q manipulator robotics Robotics Sharif

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

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

Autonomy q Autonomy is the ability to make one’s own decisions and act on them. q For robots, autonomy means the ability to sense and act on a given situation appropriately. q Autonomy can be: q complete (e. g. , R 2 D 2) q partial (e. g. , tele-operated robots) Robotics Sharif

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

State: what can be known? q A sufficient description of the system q Can be: q. Observable: robot always knows its state q. Hidden/inaccessible/unobservable: robot never knows its state q. Partially observable: the robot knows a part of its state q. Discrete (e. g. , up, down, blue, red) q. Continuous (e. g. , 3. 765 mph) Robotics Sharif

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

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

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. ) q This is called a representation or an internal model. q Representations/models have a lot to do with how complex a controller is! q Robotics Sharif

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

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

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