Special Topics in Computer Science Computational Modeling for Snake-Based Robots Introduction Week 1, Lecture 1

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Special Topics in Computer ScienceComputational
Modeling for Snake-Based RobotsIntroductionWee
k 1, Lecture 1

• William Regli
• Geometric and Intelligent Computing Laboratory
• Department of Computer Science
• Drexel University
• http//gicl.cs.drexel.edu

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Team 1

• Lead Institution Drexel University
• PI William Regli, co-PI Michael Piasecki
• University of Maryland _at_ College Park
• SK Gupta
• University of North Carolina _at_ Chapel Hill
• Ming Lin and Dinesh Manocha
• University of Wisconsin _at_ Madison
• Nicola Ferrier, Vadim Shapiro, Krishnan Suresh

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About the Team

• W. Regli
• CS, ECE and Mech E
• 1997 NSF CAREER
• M. Piasecki
• Civil
• SK Gupta
• Mech E
• PECASE, CAREER, and ONR YIP
• M. Lin
• CS
• CAREER

• D. Manocha
• CS
• PYI, ONR YIP, Sloan Fellow
• N. Ferrier
• Mech E
• NSF CAREER
• V. Shapiro
• Mech E, Math CS
• NSF CAREER
• K. Suresh
• Mech E

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Goals and Objectives

• Build and play with robots
• Course is fundamentally about modeling
• Mathematically model robot kinematics and
  dynamics
• Geometrically model robot design
• Virtually simulate robot behavior and performance
• Document experiences in GICL Wiki for
• Use by future generations of students
• Development of outreach materials (I.e. K-12)
• Development of demonstration materials
• Illustrate comprehensive, multidisciplinary,
  engineering modeling

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Course Outcomes

• The goal of this class is to build comprehensive
  engineering models of biologically-inspired
  robotic systems. Students completing this class
  will
• be able to identify problems resulting from the
  interdisciplinary interactions in bio-inspired
  robots
• perform system engineering to design, test and
  build bio-bots
• be able to apply informatics principles to
  bio-bot design and testing
• gain experience using a variety of pedagogically
  appropriate hardware (i.e. Lego Mindstorms,
  Roombas, etc) and software tools (see above) for
  robot design/analysis.

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Hardware Available

• Lego MindStorms Robot Kits, V1
• Note I will buy V2 or other modules as needed
• IRobot Roomba
• Sony Aibo
• ERS 7M3
• HP iPAQs
• 3800 and 5400 series

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Lego Mindstorms Kits

• 12 1st generation kits
• Motors, sensors, handyboards, etc
• Many examples on the web of bio-lego designs

http//www.bea.hi-ho.ne.jp/meeco/index_e.html
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iRobot Roomba

• Basic vacuum cleaner robot, but
• Has USB port
• Hacker guides
• http//www.roombareview.com/hack/
• Issues
• Not particularly bio-inspired

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Sony Aibo

• Sadly, discontinued
• Happily, we have 2
• Fully programmable
• Quadruped motion
• Internal wifi, cameras, etc
• Lots of tools on the internet for hacking Aibos

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Also available HP iPaqs

• More interesting behaviors might require more
  computational power
• Several late-model HP iPaqs can be made available
  to the class

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Given the hardware, What do we mean by modeling?
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What do we mean by modeling?

• There are several kinds we care about in this
  class
• System modeling
• Software, hardware, power, sensors and their
  interactions
• CAD/3D/Assembly Modeling
• Geometry, topology, constraints, joints and
  features
• Functional Modeling
• Intended use (or function) for the device (note,
  device may have other unintended functions or
  uses)
• Behavioral Modeling
• System inputs/outputs, motion characteristic, etc
  that achieve the function
• Physics-based modeling
• Statics, kinematics, dynamics and laws of physics
• Information Modeling
• Data, relationships, semantics (meaning)

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Basic Engineering for CS Students

• Statics The branch of physics concerned with the
  analysis of loads (force, moment, torque) on a
  physical systems in static equilibrium, that is,
  in a state where the relative positions of
  subsystems do not vary over time, or where
  components and structures are at rest under the
  action of external forces of equilibrium.
• Kinematics The branch of mechanics (physics)
  concerned with the motions of objects without
  being concerned with the forces that cause the
  motion.
• Inverse Kinematics The process of determining
  the parameters of a jointed flexible object in
  order to achieve a desired pose.
• Dynamics The branch of classical mechanics
  (physics) that is concerned with the effects of
  forces on the motion of objects.

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Physics-Based Modeling

• The creation of computational representations and
  models whose behaviors are governed by the laws
  of the physical world
• In the context of bio-inspired robots create an
  virtual environment for creation, testing and
  simulation of virtual robot design

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An example of a multi-disciplinary engineering
model
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Designing a Windshield Wiper

• From D. Macaulay, How Things Work
• What are the models?
• Functional
• Behavioral

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Models (1)

• Functional model
• The function of a windshield wiper is to remove
  dirt from the surface of a cars windshield
• Behavioral model
• Input motor rapidly rotating around the z axis
• Output oscillation in the yz plane with low
  frequency

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Models (2)

• CAD Models
• 3D models with joints and constraints
• Typically consist of
• Part models
• Assembly model(s)
• Formats can be 3D solid or 3D wireframe

3 Lego models of a wiper assembly
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Models (3) Information
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Models (3) Information

• Information modeling representations
• XML, OWL, FOL, UML
• Information modeling tools
• Protégé, Ontobuilder, Rational, etc
• Information modeling tasks
• Knowledge engineering, ontology building,
  creating a knowledge base, functional modeling,
  etc.

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Physics-based Models

• Kinematics (i.e. Animation)
• Just move the parts based on joints constraints
• Dynamics
• Incorporate forces, motor torques, power
  consumption, friction, etc
• Other issues
• collision detection algorithms that check for
  intersection, calculate trajectories, impact
  times and impact points in a physical simulation

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End Result of this Class

• 10-to-12 comprehensive engineering models of
  bio-inspired robot designs
• Individuals, teams (1-to-2 people)
• All documentation in the Wiki
• README.TXT-like instructions so as to make work
  reproducible
• Your audience Projects could be accessible to
  K-12 students or Frosh design

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Grading

• Three duties
• 15, Weekly scribe everyone will get a turn
  scribing notes and discussion from each weeks
  class into the Wiki. The more details the better
  (i.e. scribe is encouraged to back-fill
  discussion with links and references and to-do
  items).
• 35 Weekly progress each person/group will set
  up a project space in the Wiki to document
  complete design and modeling project
• Instructor will use the discussion mechanism to
  post feedback and monitor progress students
  welcome to comment on the work of other students
  vandalism harshly punished
• 50 Final project due on or before finals week.
  Includes walking robot, mathematical and physical
  models, and Wiki pages.

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Bio-Inspired Robot Locomotion Topics

• Explain motivation for bio-inspiration in mobile
  robot design
• What ideas can nature offer engineers?
• Can bio-inspired designs outperform traditional
  technology?
• Identify important design parameters in nature
• How can we quantify and evaluate nature?
• How can we measure maneuverability and the
  ability to navigate various terrain?
• Show successful implementation of bio-inspiration
  in mobile robot design
• How is the source for bio-inspiration chosen?
• How is the bio-inspiration implemented into the
  design?
• What advantages does the bio-inspired robot offer
  over the traditional robot alternatives?

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Some Concepts from Nature
???
???

• Cockroach
• Stick Insect
• Spider

• Scorpion
• Crab
• Lobster

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Some Concepts from Nature

• Dog
• Gorilla
• Human

???
???

• Snake
• Gecko
• Dinosaur

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Example Snake Robot Applications

• Search and Rescue
• Urban environments
• Natural environments
• Planetary surface exploration
• Minimally invasive surgery / examination
• Pipe inspection / cable routing

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Example Snake Robot Applications

• Snakes are also being used as inspiration for
  stationary robots that are capable of complex
  manipulations.
• Bridge inspection
• Disarming bombs
• Construction/repair in space

http//voronoi.sbp.ri.cmu.edu/serpentine/serpentin
e.html
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Design Problem

• Design requirements
• Small body diameter
• Small area required for locomotion
• High maneuverability
• Ability to navigate obstacles
• Locomotion through various environments
• Dirt
• Rocks
• Water
• Obstacles

• Application Search and rescue
• Motivation
• Hazardous environments
• Further collapse
• Fire and toxic gases
• Narrow spaces
• Obstacles may be densely packed
• People, devices, or conventional robots may not
  fit

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Conventional Robots

• Require large cross sectional areas for passage
  due to wheels or legs
• Cannot navigate through narrow spaces
• Have limited maneuverability
• Limited by terrain and obstacle height

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Where do we start?

• Projects should focus on robot locomotion and
  gait
• Wheels are not allowed
• Identify bio-mimetic behaviors
• i.e. 4 legs, make a mathematical model of
  movement for each leg, how many joints does each
  leg need, etc
• Build some bots
• Legos are probably easiest to start with
• Iterate between working in the physical world and
  enhancing the virtual world
• Objective create as complete and high-fidelity
  model as possible!
• When in the virtual world, youll need to learn
  about and teach yourself a number of tools
• CAD/CAE, 3D, etc.

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Project Examples

• 1-to-10 legged robot
• Turtle, ant, spider, etc.
• Snake that lifts its head
• i.e. climb up a stair step
• Jumping robot
• How high can you jump? How far (Frog)?
• Tumbling robot
• i.e. Star Wars
• Whatever your imagination can think up!

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Software to Investigate

• Anything is fair game! Part of this classes
  goals is to explore what works best in the
  classroom
• Software is needed for
• Design
• Modeling
• Simulation

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Modeling Software

• CAD Systems
• Pro/ENGINEER
• SDRC/UG I-DEAS
• AutoCAD, MicroStation, SolidWorks
• Lower level
• Models OpenCascade, ACIS, Parasolid
• Rendering OpenGL, DirectX

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Simulation Software

• OpenSource
• Open Dynamics Engine
• Open Source dynamics collision detection
• Game engines
• Havoc
• CAD
• Pro/MECHANICA, Adams,
• Other
• Matlab, maple

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Initial Data

• Lego Models
• http//gicl.cs.drexel.edu/repository/datasets

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Discussion Topics

• Engineering Datatypes
• 2D/3D, standards, proprietary
• How to represent an assembly
• Role of the Wiki
• Expectations of the scribe
• Help spend money!

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Other Events This Term

• Two talks sponsored by GRASP Lab
• Fridays at 11am
• THIS FRIDAY Daniella Rus, MIT
• Oct 13 Dinesh Manocha, UNC

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END
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Issues in Physics-Based Modeling of Bio-Robots

• One needs to algorithmically and

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Engineering Design