1 Introduction to AI Robotics (MIT Press)Chapter 11 Course Objectives Know what it takes to make a...

Introduction to AI Robotics (MIT Press) Chapter 1 1

1 Course Objectives

• Know what it takes to make a robust autonomous robot work:– Sense/Think/Act

• Understand the important, approaches, research issues and challenges in autonomous robotics.

• Know how to program an autonomous robot.


1 What Can Robots Be Used For?• Manufacturing

• 3 Ds

– Dirty

– Dull

– Dangerous

• Space

– Satellites, probes, planetary landers, rovers

• Military

• Agriculture

• Construction

• Entertainment

• Consumer?


1 History of Intelligent Robotics

• 1940s– First remote manipulators for hazardous

substances

• 1950s– Industrial manipulators: “reprogrammable and

multi-functional mechanism designed to move materials, parts, tools…”

– Closed loop control


1 History Continued• 1955 – term “AI” coined• 1960s manufacturing robots

– Automatic guided vehicles (AGVs)– Precision, repeatability– Emphasis on mechanical aspects

• 1970s – Planetary landers– Machine vision research expands

• 1980s– Black factory– First intelligent autonomous robots:

• Shakey, Stanford Cart, etc


1 History Continued

• 1990s– Symbolic AI/Robotics stalls

– Reactive/Behavior-based robotics emerges

• 2000s– ?


1 Intelligent Robot

• Mechanical creature which can function autonomously– Mechanical= built, constructed

– Creature= think of it as an entity with its own motivation, decision making processes

– Function autonomously= can sense, act, maybe even reason; doesn’t just do the same thing over and over like automation


1 “Intelligent” Robotics

• Basic robot primitives : Sense/Think/Act

• Three paradigms (architectures): - Hierarchical (Deliberative):

Sense ->Plan ->Act ; - Reactive: Sense -> Act; - Hybrid (Deliberative/Reactive):

Plan -> Sense -> Act


1 Ways of Controlling a Robot• “RC-ing”

– you control the robot– you can view the robot and it’s relationship to the environment– ex. radio controlled cars, bomb robots– operator isn’t removed from scene, not very safe

• teleoperation– you control the robot– you can only view the environment through the robot’s eyes– don’t have to figure out AI

• semi- or full autonomy– you might control the robot sometimes– you can only view the environment through the robot’s eyes– ex. Sojouner with different modes– human doesn’t have to do everything


1 Teleoperation

• Human controls robot remotely– Hazardous materials

– Search and rescue

– Some planetary rovers

• Considerations– Feedback (video, tactile, smell?)

– User interfaces (cognitive fatigue, nausea)

– Time/distance


1 Components of a Telesystem(after Uttal 89)

• Local – display

– Local control device

• Communication

• Remote – sensor

– mobility

– effector

– power

Display

Control

Sensor

Mobility

Effector

Power

Communi-cation

Local

Remote


1 Example

Local

Remote


1 Typical Run


1 Problems that You Saw• no feedback, couldn’t really tell that the robot was

stuck but finally got free– robot doesn’t have “proprioception” or internal sensing to tell

you what the flippers were doing. No crunching noises, no pose widget to show the flippers

• no localization, mapping-> no idea how far traveled• partial solution: better instrumentation (but can’t do dead

reckoning well)

– operator doesn’t have an external viewpoint to show itself relative to the environment

• solution: two robots, one to spot the other

• communications dropout, even though ~3 meters away• lighting conditions went from dark to very bright

– hard for computer vision or human to adjust


1 DarkStar+7 seconds=DarkSpot

• 7 second communications lag (satellite relay)

• “interruption” lag on part of operator


1 Predator:~7:1 human to robot ration

• 4 people to control it (52-56 weeks of training)– one for flying

– two for instruments

– one for landing/takeoff

• plus maintenance, sensor processing and routing

• lack of self-awareness– in Kosovo, come along side in helicopter and shoot down

Leo’s unofficialPredator page


1 Teleop Problems

• cognitive fatigue

• communications dropout

• communications bandwidth

• communications lag

• too many people to run one robot


1 Telesystems Best Suited For:

• the tasks are unstructured and not repetitive

• the task workspace cannot be engineered to permit the use of industrial manipulators

• key portions of the task require dexterous manipulation, especially hand-eye coordination, but not continuously

• key portions of the task require object recognition or situational awareness

• the needs of the display technology do not exceed the limitations of the communication link (bandwidth, time delays)

• the availability of trained personnel is not an issue


1 Teleop Solutions

• Telepresence– improves human control, reduces simulator sickness and cognitive

fatigue by providing sensory feedback to the point that teleoperator feels they are “present” in robot’s environment

• Semi-autonomous– Supervisory Control

• human is involved, but routine or “safe” portions of the task are handled autonomously by the robot

• Shared Control– human initiates action, interacts with remote by adding perceptual inputs or

feedback, and interrupts execution as needed

• Traded Control– human initiates action, does not interact

– Mixed Initiative (Guarded Control)• robot doesn’t let the operator injure the robot (without override)

• “whoever figures it out first”


1 Collaborative Teleoperation

Urban is stuck, Inuktun can’t help from current perspective

1. Driven off 3rd floor2. Hoisted to 2nd floor by tether3. Has better view, changing

configuration & rocking extend view

mpg: June 2, 2000 SRDR Miami Beach: view from Inuktun as it falls mpg: June 2, 2000 SRDR Miami Beach: view from Inuktun from hoisted position

1

2

3

still: June 2, 2000 SRDR Miami Beach


1 2000 AAAI Mobile Robot

• 2 robots helping each other reduced collision errors, sped up time navigating confined space, righting


1 Example:Mixed-Initiative & Collab. Teleop

• 9/2000 DARPA Tactical Mobile Robots demonstration

• Robot used an intelligent assistant agent to look for signs of snipers hiding in urban rubble

– motion– skin color – difference in color– thermal (IR camera)

• Human navigated mother robot using viewpoint of 2nd robot (not in picture)

• Once deposited the human moved the daughter robot, and either saw a sniper or was alerted by the agent


1 AI provides the “other stuff”

• knowledge representation• understanding natural langugage• learning• planning and problem solving• inference• search• vision


1 Summary

• Teleoperation arose as an intermediate solution to autonomy, but it has a number of problems:cognitive fatigue, high comms bandwidth, short delays, and many:one human to robot ratios.

Telepresence tries to reduce cognitive fatigue through enhanced immersive environments

Semi-autonomy tries to reduce fatigue, bandwidth by delegating portions of the task to robot

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