Announcement

Collapse
No announcement yet.

NSF Workshop on Geometric Uncertainty in Motion Planning

Collapse
This topic is closed.
X
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • NSF Workshop on Geometric Uncertainty in Motion Planning

    Further to Mr Harvey's (Salt Lake City) recent postings on collision
    detection and avoidance in Xray systems, the following posting from
    Usenet's comp.robotics newsgroup seems relevant. The full ftp report
    contains the email addresses of all organisers and participants.

    hjw

    -----------------------------------


    Article 2682 in comp.robotics:
    From: goldberg@twister.usc.edu (Kenneth Goldberg)
    Subject: Recent NSF Workshop
    Date: 18 Aug 1992 13:18:22 -0700
    Organization: University of Southern California, Los Angeles, CA
    Sender: goldberg@twister.usc.edu (Kenneth Goldberg)
    Distribution: world
    Message-ID:

    Anyone interested in current research issues, especially with
    regard to factory applications, is invited to read the following.
    An expanded version is also available via ftp.

    Summary Report and Bibliography
    Workshop on Geometric Uncertainty in Motion Planning
    Catalina Island, CA. June 15-17, 1992
    (Sponsored in part by National Science Foundation grant IRI-9208161)

    Organizers:
    Goldberg, Ken, USC
    Mason, Matt, CMU
    Requicha, Ari, USC

    NSF Coordinator:
    Howard Moraff, NSF IRIS Div.

    Participants:
    Agraval, Amit, USC
    Brost, Randy, Sandia
    Cameron, Alec, Philips
    Canny, John, UC Berkeley
    Carlisle, Brian, Adept Technology Inc.
    Erdmann, Mike, CMU
    Gottschlich, Susan, RPI
    Jennings, Jim, Cornell
    Latombe, Jean-Claude, Stanford
    Lozano-Perez, Tomas, MIT
    Lumelsky, Vladimir, UWisc
    Mishra, Bud, NYU
    Peshkin, Mike, Northwestern
    Popplestone, Robin, UMass
    Rao, Anil, USC
    Rimon, Elon, Caltech
    Sanderson, Art, RPI
    Strip, David, Sandia
    Tilove, Bob, GM
    Yap, Chee, NYU

    -----------------------------------------------------
    Introduction:

    In robotics, the problem of planning *collision-free* motions has
    received considerable attention in the past decade; results have now
    been collected into a textbook (Latombe, 1991). For manufacturing
    however, robots must bring parts into contact for grasping, packing
    and assembly. As noted by Latombe, the problem of planning reliable
    "collisions" is complicated by geometric uncertainty: things differ
    from their ideal shapes, and they are not where they're supposed to
    be. Since human programmers have difficulty keeping track of all
    possible conditions, automated planning methods are needed so that
    robots can become more reliable and practical for industry.

    There is a formal approach to planning that addresses uncertainties
    arising from: sensor noise, control error, and inaccurate models of
    the environment. This approach, based on the geometry of
    configuration space, is sometimes called *fine motion planning* due to
    a seminal paper by Lozano-Perez, Mason, and Taylor (1984).

    With the support of several NSF programs (particularly Robotics and
    Machine Intelligence and Dynamic Systems and Control) the Catalina
    workshop brought together a group of researchers and
    representatives from industry to review past work, assess its impact
    on industry, and recommend priorities for future research.

    -----------------------------------------------------
    Summary of Observations and Recommendations

    This section briefly summarizes the observations and recommendations
    made during the workshop. Following is a detailed summary of
    individual presentations and a list of relevant references.

    While sensing has traditionally been used to reduce geometric
    uncertainty, mechanical compliance (intentionally sliding parts
    against each other) is a useful alternative. Although compliance is
    widely used in manufacturing, for example in vibratory bowl feeders,
    computational algorithms for applying these techniques are only
    beginning to emerge. One fundamental question is how to discretize
    the infinite set of robot commands into a manageable set of
    equivalence classes. Another question is how to incorporate sensor
    queries with robot commands to decide when parts have been
    successfully arranged.

    Planning for repetitive assembly occurs off-line. The LMT paper and
    subsequent publications provide a useful computational framework based
    on backchaining from a goal configuration. In its most general form,
    motion planning with uncertainty is computationally intractable.
    However in non-pathological cases, existing algorithms find robust
    plans in a few minutes. Further speedups may be gained with
    randomized or approximate algorithms.

    It is easier to plan with less information. This follows from the
    fact that there are fewer alternatives to consider during planning.
    Thus automated planning may be most efficient for robot systems with
    few degrees of freedom and simple sensors. Also, detailed geometric
    analysis can be avoided during the non-contact phases of assembly.

    Planning should not be restricted to robot commands. In a structured
    environment such as a factory, the environment itself can be viewed as
    a variable, ie, the design of sensors, feeders, and fixtures can be
    specified based on part geometry. Furthermore, we can in principle
    modify part geometry and tolerances to facilitate manufacture.
    Although humans have designed workcells for decades, automated
    planning algorithms could greatly reduce set-up times and increase
    performance efficiency for competitive manufacturing.

    Industrial users require reliable systems. Although the primary
    motivation behind autonomous planning is to increase robot
    reliability, the algorithms must be rigorously tested with physical
    experiments. New planning software should be made accessible to the
    manufacturing community. This requires code that is compatible with
    existing CAD systems and well-designed user interfaces. A PhD should
    not be required to reprogram robots on the factory floor.

    Measures of progress are needed in this area. Latombe's text is a
    good start. To develop the scientific base for automated manufacture,
    it will be important to identify and solve well-formed research
    problems that explicitly address geometric uncertainty.

    -----------------------------------------------------
    Summary of Presentations:

    .

    To get and print a copy of the full (19 pp.) report on
    UNIX systems:

    % ftp 128.125.51.19
    Connected to palenque.usc.edu.
    220 palenque.usc.edu FTP server (SunOS 4.1) ready.
    Name (palenque.usc.edu:saavedra): anonymous
    331 Guest login ok, send ident as password.
    Password:
    230 Guest login ok, access restrictions apply.
    ftp> cd pub
    200 PORT command successful.
    ftp> get USC_IRIS_297.ps.Z
    ftp> quit
    % uncompress USC_IRIS_297.ps.Z
    % lpr USC_IRIS_297.ps

    Or, for a hardcopy contact:

    Delsa Castelo
    IRIS Group, 204 Powell Hall
    University Park, University of Southern California
    Los Angeles, CA 90089-0273
    End of article 2682 (of 2682)--what next? [npq]
Working...
X