Transcript Revolution in Robotics and Intelligent Control

Telerobotics
a new paradigm
Dr. Reuven Granot
[email protected]
[email protected]
Courtesy of the Center for Robot-Assisted Search and Rescue.
BBC News
Monday, 17 September, 2001, 15:20 GMT
Robots aid New York rescue workers
Smoldering ruins: Robots can go where people
can't
• Robots are being used to search for victims amid the rubble of the
twin towers of the World Trade Center in New York.
• Three small experimental robots are being lowered into gaps
between collapsed buildings to assist in the recovery of bodies.
• They are each about the size of a shoebox and are operated by hand.
National Institute for Search and Rescue
Center for Robot-Assisted Search and Rescue
Summary statistics of the first 11 days of rescue and recovery search
Arrival at Stewart Air Field: Tuesday, Sept 11, 17:30
Arrival at JAAVITS center: Wednesday, Sept 12, 01:00
Arrival at Ground Zero: Wednesday, Sept 12, 06:00
Victims found: 3-5 – by MicroTracs and MicroVGTV
Voids searched: 2 (1 declared safe by rescuers & a victim found upon entry, 1 declared unsafe) - by
MicroTracs and Solem
Buildings searched: 3 from 5 viewpoints-by UrBot, PackBot, Talon
Number of robots on site: 17 (though the number varied)
Robots deployed at Ground Zero: 8
Personnel on-site: in addition to Blitch, Foster-Miller (3), iRobot (8), SPAWAR (3), USF (4)
Lost robots: 1 – Solem
Damaged robots: 2 – MicroTracs and MicroVGTV, both repaired on-site
Number of excursions to Ground Zero: 11- 5 times actually inside the rubble pile on WTC 2, Marriott,
and surrounding areas, the rest on-station with task forces
Size of robots: MicroTracs and MicroVGTV are size of a shoebox and use tethers, others are size of small suitcase and
can be operated through wireless.
Sewer Insert
A void searched by Solem
Solem
Courtesy of the Center for Robot-Assisted Search and Rescue.
A building searched by
UrBot
UrBot
Courtesy of the Center for Robot-Assisted Search and Rescue.
A building searched by
PackBot
PackBot
Courtesy of the Center for Robot-Assisted Search and Rescue.
Urbie
Joint development of NASA/JPL, iRobot, CMU and USC
under DARPA/ATO contract
Purpose: mobile reconnaissance in city, police and rescue personnel.
The platforms were developed under DARPA contracts
Tactical Mobile Robotics project
Concept
Penetrate denied areas and project
operational influence in ways that
humans cannot by using reliable semiautonomous robotic platforms.
Approach:
• Integrate sensors, locomotion,
power, communications, and
sufficient smarts
• on a compact, man-portable
platform
• to provide a semi-autonomous
system
• capable of serving as an extension
of the human soldier.
Top Technical Challenges
 Robotic mobility in cluttered and complex terrain
 Machine perception for obstacle negotiation
 Autonomous operation and fault recovery
 PerceptOR
Examples of Robots
ISR Urban robot
• ISR Urban “Cowboy”
• Inuktun MicroVGTV and Inuktun
micro-track pipe crawler
• SAIC Subot
Inuktun microVGTV and micro-trak
SAIC Subot
Urban Search and Rescue (USAR) Robot Competitions
Robots made by teams from around the world went on
simulated search-and-rescue missions in Seattle on August 4,
2001 at RoboCup Rescue 2001.
2001+ RoboCup USAR
Physical Agents League
– May be untethered (no
chain), but human in the loop
– Robots (and their supporting
workstations) are a “member”
of the technical rescue team
Problems
• Mobility
• Perception
• Decision making
– Autonomously
– Intelligently
NIST Standard Test Course for USAR
prototype
Problems with Mobility
Most robots tested were unable to cope with rubble
-But weren’t designed to
June 2, 2000 SRDR Miami Beach:
Types of clutter
WTC in NY 11 Sept 2001.
Courtesy of the Center for Robot-Assisted Search and Rescue.
Problems with Mobility
Rubble at WTC NY Sept 2001
Courtesy of the Center for Robot-Assisted Search and Rescue.
Problems with Mobility
Most robots tested were unable to cope with rubble
-But weren’t designed to
Urban able to cope with rubble, but sensitive to
tracks containing plastic bags, sheets, throw rugs,
draperies, etc
June 2, 2000 SRDR Miami Beach:
Types of clutter
WTC in NY 11 Sept 2001.
June 2, 2000 SRDR Miami Beach: plastic
bag caused Cowboy to throw trackpp
Courtesy of the Center for Robot-Assisted Search and Rescue.
Problems with Perception
Example: while urbot is climbing stairs
• WTC NY Sept 2001
Courtesy of the Center for Robot-Assisted Search and Rescue.
DARPA
Perception for Off-Road Robotics
Expected Trends
Spectrum of Robotic Autonomy
Manned
Teleoperation
Level of human
interaction
100%
0%
Manned
Teleoperation
Semi-autonomous
Starting
Point
Today
PerceptOR
Autonomous
Long
Term
Goal
Focus of PerceptOR – applied to
autonomous mobility
Semi-autonomous
Autonomous
PerceptOR seeks to define the reduction of human
interaction based on improvements in autonomous mobility.
Some relevant technologies are already available and
used in newly developed intelligent toys and humanoids.
AIBO Entertainment robot
from Sony
Humanoids from Honda
By 2050, develop a team of fully
autonomous humanoid robots
that can win against the human
world champion team in soccer.
• RoboCupJunior is a project-oriented educational initiative.
• It is designed to introduce RoboCup to primary and
secondary school children.
RoboCupSoccer is divided into
the following leagues:
• Simulation league
RoboCupRescue Search
and Rescue for Large
Scale Disasters:
• Small-size robot league
• simulation project
• Humanoid league
• Middle-size robot league
• Four-legged robot league
• physical robots project.
RoboCup-2002 Fukuoka / Busan June 19th - June 25th, 2002
The Sixth Robot World Cup Soccer Games and Conferences,
Official Site: http://www.robocup2002.org/
A paradigm is a philosophy or set of assumptions and
techniques, which characterize an
approach to a class of problems.
A machine can be distantly operated by:
• continuous control: the HO is responsible to continuously
supply the robot all the needed control commands.
• a coherent cooperation between man and machine, which
is known to be a hard task.
A telerobot is a robot that determines its actions
based on some combination of human input and
autonomous control.
Telerobotics is a form of Supervised Autonomous Control.
The spectrum of control modes.
A telerobot can use:
• traded control:
control is or at
operator or at the
autonomous subsystem.
• shared control: the
instructions given by
HO and by the robot
are combined.
• strict supervisory
control: the HO
instructs the robot,
then observes its
autonomous actions.
Solid line= major loops are closed through computer, minor loops through human.
The need for
Collaborative Research
•
•
•
•
The task is hard to achieve
Needs expertise in many disciplines
Needs state-of-the-art components
Fast advance/ quick changes in the required
technology
Collaborative Research
The incubation phase has to be done on shared
research test bed that is:
– supplied and supported through the Internet by
partner research groups,
• as opposed to developed products, which are limited
by the negotiated financial, technical and market
oriented constrains.
–
–
–
–
agreed on paradigm and architecture
state-of-the-art components
highly reliable environment (quality)
developed on agreed standards
Robot Architecture Major Classes/Categories
A control architecture provides a set of principles for
organizing a control system.
– It provides structure and constraints which aid the designer
in producing a well-behaved controller.
Intuitively, this means that there are infinitely many ways to structure
a robot program, but they all fall into one of major classes
/categories of control:
deliberative
reactive
3) behavior-based
hybrid
look-ahead: think/plan, then act
no look-ahead: react
distribute thinking over acting
combine 1+2, think slowly, react quickly
Real time Control Systems
A Reference Model Architecture
For Teleoperation and Telerobotic applications
• RCS allows for
shared control as
well as for strict
supervisory
control, in which
HO can directly
instruct each
intelligent node.
RCS adopts a
• hierarchical architecture
• multilevel, each level deals with different resolution in
 space (range)
 time
The Behavior Generator Module in RCS
Agents act on behalf of
their supervising agent
• assign jobs
• plan
• select and
coordinate plans
• execute
What are Behaviors?
• typically have the following properties:
– are feedback controllers but extended in time
– achieve specific tasks/goals
– can directly connect sensors and effectors
• When assembled into distributed representations, behaviors can be
used to look ahead but at a time-scale comparable with the rest of the
behavior-based system.
An individual behavior is a stimulus/ response pair for a
given environmental setting that is modulated by attention
and determined by intention.
 prioritizes tasks and focuses sensory resources
 determines which set of behaviors should be active
based on the robotic agent’s goals and objectives.
 Search and planning takes too long
Deliberative Systems
 Based on the Sense  Plan  Act model
 Inherently sequential
 Planning requires search
 Search requires a world model
The representation must be constantly
updated and checked
Problem 4: Use of Plans
Problem 1: Time Scale
"too much information"
 Generating a plan is slow.
Problem 2: Space
 Generating a plan can be large
Problem 3: Information
"too little information"
The resulting plan is only useful if:
a) the environment does not change
b) the representation was accurate enough
c) the robot's effectors are accurate enough to perfectly execute each step of
the plan in order to make the next step possible
Reactive Systems
A purely reactive behavior-based method may be
represented by a horizontal (sequential) decomposition,
while the deliberative Sense-Plan-Act paradigm has
vertical (concurrent) decomposition.
Hybrid Systems
 Combine the two extremes
 reactive system on the bottom
 deliberative system on the top
 connected by some intermediate layer
 Layers must operate concurrently.
 Different representations and time-scales between the
layers.
A modern hybrid system typically consists of three components:
 a reactive layer
 a planner
 a layer that puts the two together.
=> Hybrid architectures are often called three-layer architectures.
Behavior-Based Systems
 An alternative to hybrid systems
 Have the same capabilities
 the ability to act reactively
 the ability to act deliberately
 There is no intermediate layer
 A unified, consistent representation is used in the
whole system => concurrent behaviors
 That resolves issues of time-scale.
• Regarding the architecture of robotic systems two key issues
distinguishing architectures, as had to do with
– time-scale (reactive) and
– looking ahead (deliberative).
• A third key issue we need to consider is modularity, i.e., the
way in which the architecture decomposes into components.
Task decomposition
 SPA architecture uses a functional (hierarchical ) decomposition
 Reactive architecture uses a task-oriented decomposition
 RCS uses a functional with different resolution (scale) in time and
space at each level of the hierarchy.
• Behavior-based systems (BBS) use behaviors as the underlying
module of the system, i.e., they use a behavioral decomposition.
Control Agents
A control agent or a control arbitration process is designed to
observe and respond to the (unstructured) environment in order
to fulfill a goal autonomously.
In doing so, it acts on behalf of a superior agent or human
operator.
The agent makes decisions in order to resolve conflicts between contradicting
activities.
• An agent can be considered as a control subassembly.
• Designing local behaviors for each agent that result in the
desired global behavior (the control model) is a VERY
hard problem.
– Need for an architectural element to care about the Global Goal.
• Let’s combine RCS with BBS
– Behaviors implemented using control agents
RCS & BBS
• RCS is a type of hybrid system
– Assumes that alternative plans, as response to contingent events
can be pre-planned in relevant numbers.
• For some tasks, in special at lower layers with high control
bandwidth, a behavioral decomposition will better suite.
– Tasks may be complex only in the eye of an intelligent observer
• Behavior Generator Modules of each node in RCS already
contain (execution) agents.
• A Behavioral Agent will suppress the preplanned execution
and will be monitored directly by the superior agent in the
hierarchy.
• Expected drawback: inability to precisely predict the
output of the assemblage of behavioral agents.
The END