1 / 42

Picture of Terminator

Picture of Terminator. Introduction to Robotics (ES159) Advanced Introduction to Robotics (ES259) S pring 2007 Robert Wood 149 Maxwell Dworkin rjwood@eecs.harvard.edu www.eecs.harvard.edu/~rjwood. Personnel . Instructor: Me TFs: Shelton Yuen Dr. Benjamin Pierce. Primary:

rangle
Télécharger la présentation

Picture of Terminator

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Picture of Terminator

  2. Introduction to Robotics (ES159)Advanced Introduction to Robotics (ES259)Spring 2007Robert Wood149 Maxwell Dworkinrjwood@eecs.harvard.eduwww.eecs.harvard.edu/~rjwood ES159/ES259

  3. Personnel • Instructor: • Me • TFs: • Shelton Yuen • Dr. Benjamin Pierce ES159/ES259

  4. Primary: M. Spong, S. Hutchinson, and M. Vidyasagar, “Robot Modeling and Control”, Wiley Texts Secondary: Li, Murray, Sastry, “A Mathematical Introduction to Robotic Manipulation”, CRC Press ES159/ES259

  5. Lab • Multiple experiments with a 6-axis industrial robotic arm (RRR) • Forward/inverse kinematics • Velocity kinematics • Control • Path planning • Manipulation • Equipment: • Open architecture industrial arm from CRS (Catalyst-5), retrofitted by Quanser with a Matlab interface • Will require extensive use of Matlab/Simulink ES159/ES259

  6. Problem sets and exams • Problem sets: approximately every other week, due two weeks afterwards • Will often include Matlab/Simulink problems • Matlab review session(s)? • No midterm, one comprehensive final exam ES159/ES259

  7. Final projects • Required for graduate students • Bonus for undergraduates • Can involve any field of robotics • I will be happy to suggest topics • I strongly encourage you to incorporate your research into the project (or the final project into your research!) • You will have access to the following facilities: • The 159 lab arm • Machine shop • All resources in the Harvard Microrobotics Lab ES159/ES259

  8. Course outline • First 2/3: traditional analysis of robotic manipulators • Homogeneous transforms • Forward/inverse kinematics • Velocity kinematics, dynamics • Motion planning • Control • Final 1/3: introduction to special topics • Sensors and actuators • Mobile agents, SLAM • Computer vision • MEMS, microrobotics • Surgical robotics, teleoperation • Biomimetic systems Labs will follow along with these topics Active research areas, potential subjects for final projects ES159/ES259

  9. Introduction • Historical perspective • The acclaimed Czech playwright Karel Capek (1890-1938) made the first use of the word ‘robot’, from the Czech word for forced labor or serf. • The use of the word Robot was introduced into his play R.U.R. (Rossum's Universal Robots) which opened in Prague in January 1921. In R.U.R., Capek poses a paradise, where the machines initially bring so many benefits but in the end bring an equal amount of blight in the form of unemployment and social unrest. • Science fiction • Asimov, among others glorified the term ‘robotics’, particularly in I, Robot, and early films such as Metropolis (1927) paired robots with a dystopic society • Formal definition (Robot Institute of America): • "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". ES159/ES259

  10. 100s of movies Chances are, something you eat, wear, or was made by a robot 01_02 Robots in everyday use and popular culture http://www.robotuprising.com/ Roomba: $142M in sales for 2005 ES159/ES259

  11. Common applications Picture of Roomba • Industrial • Robotic assembly • Commercial • Household chores • Military • Medical • Robot-assisted surgery ES159/ES259

  12. JHUROV; Johns Hopkins Common applications • Planetary Exploration • Fast, Cheap, and Out of Control • Mars rover • Undersea exploration ES159/ES259

  13. 01_01 Industrial robots • High precision and repetitive tasks • Pick and place, painting, etc • Hazardous environments ES159/ES259

  14. 01_03 Representations • For the majority of this class, we will consider robotic manipulators as open or closed chains of links and joints • Two types of joints: revolute (q) and prismatic (d) ES159/ES259

  15. Definitions • End-effector/Tool • Device that is in direct contact with the environment. Usually very task-specific • Configuration • Complete specification of every point on a manipulator • set of all possible configurations is the configuration space • For rigid links, it is sufficient to specify the configuration space by the joint angles • State space • Current configuration (joint positions q) and velocities • Work space • The reachable space the tool can achieve • Reachable workspace • Dextrous workspace ES159/ES259

  16. 01_06 Common configurations: wrists • Many manipulators will be a sequential chain of links and joints forming the ‘arm’ with multiple DOFs concentrated at the ‘wrist’ ES159/ES259

  17. Utah MIT hand 01_07 Example end-effector: Grippers • Anthropomorphic or task-specific • Force control v. position control ES159/ES259

  18. 01_09 Common configurations: elbow manipulator • Anthropomorphic arm: ABB IRB1400 • Very similar to the lab arm (RRR) ES159/ES259

  19. 01_10 Workspace: elbow manipulator ES159/ES259

  20. 01_12 Common configurations: Stanford arm (RRP) • Spherical manipulator (workspace forms a set of concentric spheres) ES159/ES259

  21. Adept Cobra Smart600 SCARA robot 01_14 Common configurations: SCARA (RRP) ES159/ES259

  22. Seiko RT3300 Robot 01_15 Common configurations: cylindrical robot (RPP) • workspace forms a cylinder ES159/ES259

  23. 01_16 Common configurations: Cartesian robot (PPP) • Increased structural rigidity, higher precision • Pick and place operations ES159/ES259

  24. 01_17 Workspace comparison (a) spherical (b) SCARA (c) cylindrical (d) Cartesian ES159/ES259

  25. ABB IRB940 Tricept 6DOF Stewart platform ABB IRB6400 01_18 Parallel manipulators • some of the links will form a closed chain with ground • Advantages: • Motors can be proximal: less powerful, higher bandwidth, easier to control • Disadvantages: • Generally less motion, kinematics can be challenging ES159/ES259

  26. Simple example: control of a 2DOF planar manipulator 01_19 • Move from ‘home’ position and follow the path AB with a constant contact force F all using visual feedback ES159/ES259

  27. 0 1 2 0 1 2 01_20 Coordinate frames & forward kinematics • Three coordinate frames: • Positions: • Orientation of the tool frame: ES159/ES259

  28. 01_21 Inverse kinematics • Find the joint angles for a desired tool position • Two solutions!: elbow up and elbow down ES159/ES259

  29. State space includes velocity Inverse of Jacobian gives the joint velocities: This inverse does not exist when q2 = 0 or p, called singular configuration or singularity 01_23 Velocity kinematics: the Jacobian ES159/ES259

  30. 01_24 Path planning • In general, move tool from position A to position B while avoiding singularities and collisions • This generates a path in the work space which can be used to solve for joint angles as a function of time (usually polynomials) • Many methods: e.g. potential fields • Can apply to mobile agents or a manipulator configuration ES159/ES259

  31. desired trajectory controller error system dynamics measured trajectory (w/ sensor noise) actual trajectory 01_24 Joint control • Once a path is generated, we can create a desired tool path/velocity • Use inverse kinematics and Jacobian to create desired joint trajectories ES159/ES259

  32. Other control methods • Force control or impedance control (or a hybrid of both) • Requires force/torque sensor on the end-effector • Visual servoing • Using visual cues to attain local or global pose information • Common controller architectures: • PID • Adaptive • Repetitive • Challenges: • Underactuation • Nonholonomy (mobile agents) • nonlinearity ES159/ES259

  33. General multivariable control overview joint controllers motor dynamics manipulator dynamics desired joint torques state estimation sensors estimated configuration inverse kinematics, Jacobian desired trajectory ES159/ES259

  34. Sensors and actuators • sensors • Motor encoders (internal) • Inertial Measurement Units • Vision (external) • Contact and force sensors • motors/actuators • Electromagnetic • Pneumatic/hydraulic • electroactive • Electrostatic • Piezoelectric • Basic quantities for both: • Bandwidth • Dynamic range • sensitivity ES159/ES259

  35. Whegs; CWRU RHex; Michigan Mobile Agents and SLAM • For untethered and autonomous applications, the performance of a robotic system (P), whether defined by capability or robustness, can be related to an agent’s intelligence (I), mobility (M), and multiplicity (N): MicroBat; UCLA ES159/ES259

  36. Mobile Agents and SLAM • Monte Carlo localization • SLAM: ‘Simultaneous locomotion and Map-building’ ES159/ES259

  37. Computer Vision • Simplest form: estimating the position and orientation of yourself or object in your environment using visual cues • Usually a statistical process • Ex: finding lines using the Hough space • More complex: guessing what the object in your environment are • Biomimetic computer vision: how do animals accomplish these tasks: • Obstacle avoidance • Optical flow? • Object recognition • Template matching? ES159/ES259

  38. Donald; Dartmouth MEMS and Microrobotics • Difficult definition(s): • Robotic systems with feature sizes < 1mm • Robotic systems dominated by micro-scale physics • MEMS: Micro ElectroMechanical Systems • Modified IC processes to use ‘silicon as a mechanical material’ Fearing; Berkeley Pister; Berkeley ES159/ES259

  39. Surgical robotics • Minimally invasive surgery • Minimize trauma to the patient • Potentially increase surgeon’s capabilities • Force feedback necessary, tactile feedback desirable ES159/ES259

  40. BigDog; Boston Dynamics MFI; Harvard & Berkeley Ayers; Northeastern Biomimetic Robots • Using biological principles to reduce design space ES159/ES259

  41. Humanoid robots • For robots to efficiently interact with humans, should they be anthropomorphic? QRIO Sony Asimo; Honda ES159/ES259

  42. Next class… • Homogeneous transforms as the basis for forward and inverse kinematics • Come talk to me if you have questions or concerns! ES159/ES259

More Related