chapter 8pages.cpsc.ucalgary.ca/.../slides/08-robotics.pdf8. robotics introduction 8.1 what are...

Christian JacobChristian [email protected]

Department of Computer ScienceUniversity of Calgary

ChapterChapter 8 8

RoboticsRobotics————————————————————————————

8.8. RoboticsRobotics

IntroductionIntroduction

8.18.1 What are Robots Good For?What are Robots Good For?

8.28.2 What are Robots Made Of?What are Robots Made Of?

8.38.3 ArchitecturesArchitecturesClassic ArchitectureClassic Architecture

Situated AutomataSituated Automata

8.48.4 Configuration SpacesConfiguration Spaces

8.58.5 Navigation and Motion PlanningNavigation and Motion Planning

8.68.6 More Robot ExamplesMore Robot Examples


•Robot Institute of America defines a robot as areprogrammable, multifunction manipulatordesigned to move material, parts, tools or specificdevices through variable programmed motions forthe performance of a variety of tasks.

•Russell and Norvig: an active, artificial agentwhose environment is the physical world.

•Robots differ from Softbots whose environmentconsists of computer systems, databases andnetworks.

The Physical WorldThe Physical World

•The physical world is very demanding, it is:

•inaccessible - sensors are imperfect, only stimuli thatare near the agent can be perceived.

•nondeterministic - a robot needs to deal withuncertainty

•nonepisodic - effects of an action change over time

•dynamic - robot needs to decide when to think andwhen to act immediately

•continuous - states and actions are drawn from acontinuum of physical configurations and motions

What are robots good for?What are robots good for?

•Manufacturing and materials handling


•Gofer robots

Bell & Howell Mailmobile


•Gofer robots

Carnegie Mellon’s Nomad


•Hazardous environments

Lunokhod Moon Robot


•Hazardous environments

Dante II Frame Walking Robot


•Telepresence and virtual reality

The Wheelbarrow, a bomb disposal robot



Advanced Tethered Vehicle (ATV)



Advanced Robot and Telemanipulator System for Minimal Invasive Surgery(ARTEMIS)


•Augmentation of human abilities

Sigourney Weaver in the movie Aliens


•Augmentation of human abilities

General Electric’s Walking Truck

What are robots made of?What are robots made of?

•Effectors: Tools for Action

•Locomotion

•Manipulation

•Sensors: Tools for perception

•Proprioception

•Force Sensing

•Tactile Sensing

•Sonar

•Camera Data


•Effectors: Locomotion

Carnegie Mellon’s Ambler


•Effectors: Locomotion

MIT’s 3D Hopper


•Effectors: Manipulation

Degrees of Freedom


•Sensors: Proprioception

MIT’s Spring Flamingo

HapticsHaptics

❏❏ MIT Touch LabMIT Touch Lab


•Sensors: Force Sensing

MIT’s Phantom


•Sensors: Tactile Sensing

MIT’s Planar Grasper


•Sensors: Sonar

ActivMedia’s Peoplebot


•Sensors: Light Sensors

Grey Walter’s Tortoise: Machina Speculatrix


•Sensors: Camera Data

The Beast: Johns Hopkins University


•Sensors: Camera Data

MIT’s Fast Eye Gimbals

ArchitecturesArchitectures

The architecture of a robot defines how the job ofgenerating actions from percepts is organized. It isbasically the control mechanism of the robot.

•Classical Architecture

•Situated Automata

Architectures: Classical ArchitectureArchitectures: Classical Architecture

•A robot with classical architecture is given anumber of low-level actions (LLAs). It then usesthese LLAs to reason about the effects ofperforming a sequence of these LLAs.

The problem with this is that due to things likewheel slippage and measurement errors anylengthy sequence of actions is prone to fail.


•Classical Architecture

SRI’s Shakey

Architectures: Situated AutomataArchitectures: Situated Automata

•The process of deliberating is often too expensiveto generate real-time behavior. Situated automatado not explicitly reason, they operate by reflex.

A situated automata has two parts:

- The first collects sensor inputs and updates thestate register accordingly.

- The second looks at the state register andcalculates output (actions).

Thus a situated automata does not plan, it justdoes whatever it knows to do given the state it isin.


•Situated Automata

SRI’s Flakey

Configuration SpacesConfiguration Spaces

Configuration Space is the path where a robot canmove from one position to another.

•Generalized configuration space

•Recognizable sets

Generalized configuration space


❏❏ Generalized configuration spaceGeneralized configuration space includes other objects as part of the includes other objects as part of theconfiguration, which could be movable, variable in shapes (i.e.configuration, which could be movable, variable in shapes (i.e.scissors or staples), or deformable (i.e., string or paper).scissors or staples), or deformable (i.e., string or paper).

Recognizable Sets


❏❏ Includes envelope of possible configurationsIncludes envelope of possible configurations

Navigation and Motion PlanningNavigation and Motion Planning• Cell decomposition

• Skeletonization

• Fine-motion (bounder-error) planning

• Landmark-based navigation

• Online algorithms

Navigation and Motion PlanningNavigation and Motion Planning•Cell decomposition

• Breaks continuous space into a finite number ofdiscrete search problems

Bell & Howell Mailmobile

Navigation and Motion PlanningNavigation and Motion Planning• Skeletonization methods

• Computes a one-directional “skeleton” (subset) ofthe configuration space, yielding an equivalent graphsearch problem

Navigation and Motion PlanningNavigation and Motion Planning• Fine-motion (Bounded-error) Planning

• This methods assume bounds on sensor and actuatoruncertainty, and in some cases can compute plans that areguaranteed to succeed even in the face of severe actuator errors

• partial knowledge of the environment is known to the system

• most of the planning is done offline

• used for planning small, precise motions of assembly robots

Navigation and Motion PlanningNavigation and Motion Planning• Landmark-based navigation

• This method assumes that some regions exist in which therobot location can be pinpointed using landmarks, whereasoutside those regions it may have only orientationinformation.

• This method is both sound and complete

• The plan has at most n steps if there are n landmarks

Navigation and Motion PlanningNavigation and Motion Planning• Online algorithm

• The robot makes decisions at run time (no need for offlineplanning

• This method assumes that the environment is completelyunknown

• The robot cannot see anything. It can only sense a boundary

• The robot is equipped with a position sensor and knows thelocation of its goal.

Mars Pathfinder Sojourner Mars Exploration Rovers









8.68.6 RoboRobo sapiens? sapiens?

RoboRobo Sapiens? Sapiens?

[Kurzweil, 1990]

Seymour Papert

LOGO Robot


[Menzel and D’Aluisio, 2000]

KISMET

MIT


[Kurzweil, 1990]

WABOT, theOrgan Player

Ichiro Kato,Waseda-University,Tokyo

ReferencesReferences

•• P.P. Menzel Menzel and F. and F. D’Aluisio D’Aluisio (2000). (2000). RoboRobo sapiens — sapiens —Evolution of a New SpeciesEvolution of a New Species. Cambridge, MA, MIT Press.. Cambridge, MA, MIT Press.

•• KurzweilKurzweil, R. (1990). , R. (1990). The Age of Intelligent MachinesThe Age of Intelligent Machines..Cambridge, MA, MIT Press.Cambridge, MA, MIT Press.

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