Robot Technology Chapter 10

1. Robot Technology Chapter 10 Robotics by Muhammad Moeen Sultan

2. Robot Introduction • General purpose(perform a variety of functions independently) • Programmable (Sequence, repetition, decision making • Anthropomorphic characteristics Perform specific functions like machine loading, spot welding, spray painting, assembly, etc. Robotics by Muhammad Moeen Sultan

3. Definition of Robot • A robot is a programmable, multifunction manipulator designed to move material, parts, tools, or special devices through variable programmed motions for the performance of a variety of tasks. Robotics by Muhammad Moeen Sultan

4. Laws of Robotics • Law 1: A robot may not injure a human being • 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 Robotics by Muhammad Moeen Sultan

5. Robot Physical Configurations • Industrial Robots come in a variety of shapes and sizes • On this base they are distinguished • Polar coordinate configuration • Cylindrical coordinate configuration • Joined arm configuration • Cartesian coordinate configuration Robotics by Muhammad Moeen Sultan

6. Polar coordinate configuration • Spherical coordinates (Partial sphere) • Rotary base • Pivot used to raise and lower an arm • In-out movement Robotics by Muhammad Moeen Sultan

7. Cylindrical coordinate configuration Swivels about a vertical axis Up-down movement In-out movement Robotics by Muhammad Moeen Sultan

8. Jointed Arm configuration Similar in appearance to human arm Rotated base, shoulder joint, elbow joint, wrist joint. Robotics by Muhammad Moeen Sultan

9. Cartesian coordinate configuration Three orthogonal slides Slides are parallel to the x,y,z axis. Robotics by Muhammad Moeen Sultan

10. Purpose of a Robot • Purpose of a robot is to perform useful task • End-effector The tool, gripper, or other device mounted at the end ofa manipulator, for accomplishing useful tasks • Hand Robotics by Muhammad Moeen Sultan

11. Degrees-of-Freedom (DOF): The number of independent motions a device can make. (Also called mobility) five degrees of freedom Robotics by Muhammad Moeen Sultan

12. Degree of Freedom Six basic motions for a robot to move in a required sequence of motions Not all robots are equipped with it Three arm and body movement and three wrist movements. Robotics by Muhammad Moeen Sultan

13. Six Degree of Freedom Robotics by Muhammad Moeen Sultan

14. Motion Systems Point-to-point (PTP) Moves from one point location to another. Can adopt any path. Examples: loading unloading, pick and place, spot welding Robotics by Muhammad Moeen Sultan

15. Motion Systems Contouring (Continuous Path) Move on a Smooth compound curve Complete path is remembered Examples: Paint spray, continuous welding. Robotics by Muhammad Moeen Sultan

16. Other technical features • Determine its efficiency, effectiveness • Some of the technical features are • Work volume • Precision of movement • Speed of movement • Weight carrying capacity • Types of drive system Robotics by Muhammad Moeen Sultan

17. Technical features • Work volume • Space within which a robot can operate. • Determined by its configuration, size and the limits of its arms. • Polar coordinates – partial sphere • Cylindrical coordinates – cylindrical • Cartesian - rectangular • Jointed arm - irregular Robotics by Muhammad Moeen Sultan

18. Technical features Precision of movement The precision with which the robot can move the end of its wrist. Spatial resolution Accuracy Repeatability Robotics by Muhammad Moeen Sultan

19. Technical features • Spatial resolution • Smallest increment of motion • Depends on the control system and feedback Control resolution= range control increments Robotics by Muhammad Moeen Sultan

20. Technical features • Accuracy • The ability of a robot to go to the specified position without makinga mistake. • Closely related to spatial resolution Robotics by Muhammad Moeen Sultan

21. Technical features • Repeatability • Ability to position a wrist back to the previously visited point. Robotics by Muhammad Moeen Sultan

22. Technical features • Speed of movement • The amount of distance per unit time at which the robot can move. • Speed of the end effectors • Determined by the weight of the object Weight carrying capacity • Lifting over 1000 lb Robotics by Muhammad Moeen Sultan

23. Types of Drive system Hydraulic (mechanical, high strength) Electric motor (stepper, servo, less strength, better accuracy and repeatability Pneumatic (quick, less strength) Robotics by Muhammad Moeen Sultan

24. End effectors Grippers Tools Robotics by Muhammad Moeen Sultan

25. Grippers Robotics by Muhammad Moeen Sultan

26. Tools as end effectors Spot welding Spray painting Drilling Grinders Heating torches Robotics by Muhammad Moeen Sultan

27. Robotic sensors Vision Tactile and proximity voice Robotics by Muhammad Moeen Sultan

28. Programming The Robot • Programming Methods • Manual Method • Walkthrough Method • Lead through Method • Off-line Programming Robotics by Muhammad Moeen Sultan

29. Manual Method Mechanical stops, cams, switches or relays Uses: short work cycle like pick and place operation video Robotics by Muhammad Moeen Sultan

30. Walkthrough Method • Manually moves the robot arm • Each movement is recorded • No worry about the cycle time • Getting the position and sequence correct Uses: spray painting, arc welding Robotics by Muhammad Moeen Sultan

31. video Robotics by Muhammad Moeen Sultan

32. Lead through Method • Use of small hand held devices • Switches, dials • Each motion is recorded in memory Robotics by Muhammad Moeen Sultan

33. Off-line programming • Similar to NC • Computer terminal • No loss of production time (no teaching) • Can be programmed when still in production Robotics by Muhammad Moeen Sultan

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35. Work Cell Control • Work with other things • Processing equipments, work parts, conveyors, tools and human operators • Coordinating all the activities within the robot workstation • Sequencing and simultaneous activities • Work cell controller Robotics by Muhammad Moeen Sultan

36. Work Cell Control • Example • Robotic arm • Machine tool • Two conveyors Robotics by Muhammad Moeen Sultan

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38. Work Cell Control • Operate Sequentially • Certain steps are completed before next operation • Picking, proper location of the piece • Start, by Loading the work piece • Machining complete Robotics by Muhammad Moeen Sultan

39. Interlocks Sequence continues until a certain condition or set of conditions has been satisfied Incoming Outgoing Robotics by Muhammad Moeen Sultan

40. Interlocks Limit switches Pressure switches Photoelectric devices Robotics by Muhammad Moeen Sultan

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