Introduction to Robotics cpsc - 460

1. Introduction to Roboticscpsc - 460

2. Textbook • Robot Modeling and Control , Mark W. Spong, Seth Hutchinson and M. Vidyasagar, Wiley 2006. ISBN-10: 0471649902 ISBN-13: 978-0471649908

3. Topics Covered • Transformations • Kinematics • Inverse kinematics • Jacobians • Trajectory generation • Robot control

4. Robot • The term ‘Robot’ was first used by the Czech playwright KarelČapek in 1920 in his satirical play called RUR (Rossum's Universal Robots) • The term robot originates from the Czech word, ‘Robota’, (pronounced "chop'ek"), meaning compulsory labor or slave KarelČapek was one of the most influential Czech writers of the 20th century. At one time the Gestapo had ranked him as "public enemy number 2" in Czechoslovakia! Cover page of the first edition The plot was simple: A man makes a robot, then the robot kills the man!

5. Robotics • The word ‘Robotics' also comes from science fiction. • Robotics was coined and was first used in “Runaround”, a short story published in 1942, by Isaac Asimov. • But it was not until 1956 that a real robot came into existence. Russian-born American scientist and writer Isaac Asimov wrote prodigiously on a wide variety of subjects. He was best known for his many works of science fiction. The most famous include: I Robot (1950), The Foundation Trilogy (1951-52), Foundation's Edge (1982), and The Gods Themselves (1972), which won both the Hugo and Nebula awards.

6. Definitions • Robotics – The science dealing with the design, construction and operation of robots • Robot – According to The Robot Institute of America (1979) a robot is “a reprogrammable, multifunctional manipulator designed to move materials, parts, tools, or specialized devices through various programmed motions for the performance of a variety of tasks." • Virtually anything that operates with some degree of autonomy, usually under computer control, has been called a robot. • Roboticist– A person who design, builds, or programs robots

7. Robots for 3D Jobs • Dull • Dirty • Dangerous

8. Advantages of Robotics • The major advantages of robots are: • Decreased labor costs • Increased precision and productivity • Increased flexibility compared with specialized machines • Robots can perform dull, repetitive jobs • Robots can operate in hazardous environments

9. Robotics Engineering • Robotics is a relatively new field of modern technology that crosses traditional engineering boundaries • Understanding the complexity of robots and their applications requires knowledge of • electrical engineering • mechanical engineering • industrial engineering • computer science

10. What it Takes to Make a Robot Robotics is a multi-disciplinary field. Mechanical Engineering – concerned primarily with manipulator/mobile robot design, kinematics, dynamics, compliance and actuation. Electrical Engineering – concerned primarily with robot actuation, electronic interfacing to computers and sensors, and control algorithms. Computer Science – concerned primarily with robot programming, planning, perception and intelligent behavior.

11. Serial Manipulators / Robots • A connection of mechanical linkages • A serial manipulator is a open kinematic chain of two or more links • Joint is the connection between 2 links • Joints constraint the motion of the connected links • Joints can be electrically, hydraulically, or pneumatically actuated.

12. Serial Manipulator Robots • Physically anchored to their workplace • Manipulator motion usually involves an entire chain of controllable joints, enabling such robots to place their effectors in any position within the workplace • Manipulators are by far the most common type of industrial robots - a 2 billion dollar industry!

13. Unimate – First Serial Manipulator

14. Manipulator Joints • Joints are either Revolute (R) or Prismatic (P) • Revolute joint allows relative angular motion between the links, like a hinge • Prismatic joint allows relative linear motion between the two links

15. Symbolic Representation of Joints

16. Revolute Joints • Rotational joints can have more than one degree of freedom (DoF) • One DoF revolute joint

17. 2 DoF Revolute Joint • Universal Joint (U)

18. 3 DoF Revolute Joint • Spherical Joint (S) • Example: Ball and Socket Joint

19. Wrist and End Effector • Wrist: the joints between the arm and the end effector / gripper. • Typically, the arm controls the position of the end effector, and the wrist controls the orientation.

20. 3 DoF WRIST • A typical wrist would have 3 DOF described as roll, pitch and yaw. • Roll - rotation around the arm axis • Pitch - up and down movement (assuming the roll is in its centre position) • Yaw - right to left rotation (assuming the roll is in its centre position)

21. End Effector • The device on the end of the arm, attached via the wrist, that performs the task, such as: • Grippers - Use to hold and move objects • Tools - Used to perform work on a part, not just to pick it up. A tool could be held by a gripper, making the system more flexible.

22. Degrees of Freedom • An object is said to have a ndegrees of freedom (DOF), if its configuration can be minimally specified by n parameters. • For a robot manipulator, the number of joints determine the number of DOF.

23. Degrees of Freedom • To reach any point in the space with an arbitrary orientation: 6 DOF (3 DOF for positioning and 3 DOF for orientation) • Less than 6 DOF: the arm cant reach any point in the space with an arbitrary orientation. • More than 6 DOF: Kinematically redundant manipulator. • Certain applications may require more than 6 DOF, for example: • Obstacle Avoidance.

24. Classification of Serial Robots • Power Source – AC / DC • Application – Assembly / Non-Assembly • Control – Servo / Non-Servo • Geometry (Manipulator Configuration)

25. Manipulators Configurations Cartesian: PPP Cylindrical: RPP Spherical: RRP Hand coordinate: n: normal vector; s: sliding vector; a: approach vector, normal to the tool mounting plate RRP (Selective Compliance Assembly Robot Arm) Articulated: RRR

26. Workspace • The Workspace of the manipulator is the total volume swept out by the end effector as the manipulator executes all possible motion. • Workspace is constrained by: • Geometry of the manipulator. • Mechanical constraint of the joints (a revolute joint may be limited to less than 360 degrees)

27. Workspace • Reachable Workspace: the entire set of points reachable by the manipulator. • Dexterous Workspace: consists of those points that the manipulator can reach with an arbitrary orientation of the end effectors. • Dexterous Workspace is a subset of Reachable Workspace

28. Workspace

29. Workspace of a Cartesian (PPP) Manipulator

30. Workspace of a Cylindrical (RRP) Manipulator

31. Workspace of a Spherical (RRP) Manipulator

32. Workspace of a SCARA (RRP) Manipulator

33. Performance Measures • Accuracy is a measure of how close the manipulator can come to a given point within its workspace. • Repeatability is a measure of how close the manipulator can return to a previously taught point.

34. Other Criteria • Payload Capacity • Dexterity • Size of Workspace • Operating Volume • Speed • Easy of Use • Cost

35. Components of a Robotic System

36. Parallel Manipulators • More than one serial manipulator arms working together • Closed Kinematic Chain

37. Areas of Robotics • Surveillance – UAVs, Drones, • Medical Robotics – Surgical Robots, Prosthetics • Mobile Robotics – Telepresence, Navigation • SWARM Robotics • Service Robotics – Refueling, Assisting • Security • Space Explortion