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STIQUITO: a small, simple, inexpensive hexapod robot

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  • STIQUITO: a small, simple, inexpensive hexapod robot

    Dear Biomch-L readers,

    The following Usenet posting seems interesting from a gait control point of
    view, one of the references quoted in the mentioned report. Interestingly,
    this posting refers to cost compensation in a university setting. Of course,
    it stands to reason that a large number of "orders" to the Computer Science
    Department at Bloomington may facilitate subsequent commercialization of this
    interesting device.

    Stiquito: A Small, Simple, Inexpensive Hexapod Robot
    Part 1. Locomotion and Hard-Wired Control

    Jonathan W. Mills
    Computer Science Department, Indiana University
    Bloomington, IN 47405, U.S.A.

    ABSTRACT: 80 figures illustrate the construction of a six-legged robot
    that walks up to 10 cm/min and carries up to 50 grams. Ninetol actu-
    ator wires drive the robot's legs. Power and control are supplied
    through a tether or with on-board batteries and electronics. The robot
    provides an inexpensive platform to study computational sensors, sub-
    sumption architectures, neural gait control, behavior of social insects,
    and machine vision. A single robot costs between $ 10 and $ 30. The
    pro-rated cost of material to construct robots in volume (200 or more)
    is less than $ 3. The design can be replicated to build complex arthro-
    pods, or colonies containing hundreds of insectoid robots.

    In a number of follow-up postings on Usenet, the pro's and con's of this
    device have been discussed. Furthermore, the non-profit nature of this
    service was re-emphasised (the author does not receive any royalties), and
    the impossibility to process purchase orders and credit cards was mentioned.
    For ordering through official channels, it was suggested that institutional
    purchasing departments prepare a check to be sent to Bloomington. I imagine
    that International Money Orders will be acceptable, while checks drawn on
    non-US banks may not be acceptable due to high banking charges; sending cash
    was discouraged.


    Ref.: R. Beers, An artificial insect. American Scientist, Sep/Oct 1991,


    Article 7073 in
    From: (Jonathan Mills)
    Subject: Stiquito, A Small Nitinol-Propelled Robot
    Summary: An inexpensive legged robot for research & education
    Keywords: Nitinol, Flexinol(tm), legged, robot
    Date: 24 Sep 92 16:36:12 GMT (corrected -- HJW)
    Organization: Indiana University, Bloomington

    Stiquito: A Small Nitinol-Propelled Hexapod Robot

    The Computer Science Department's Robotics Laboratory at Indiana
    University (Bloomington) has designed, built, and tested "Stiquito",
    a six-legged robot that you customize by adding sensors, controllers,
    power sources, etc. The robot provides an inexpensive platform to
    study computational sensors, subsumption architectures, neural gait
    control, emergent cooperative behavior, and machine vision. It is
    currently being used for research at IU, and, at a ratio of one robot
    per student, in "VLSI for Robotics" and "Machine Learning" classes.

    Stiquito is small (3cm H x 7cm W x 6cm L) and simple (32 parts)
    because its legs are propelled by nitinol actuator wires. Each
    leg has one degree of freedom. The robot walks up to 10 cm per
    minute and can carry a 9-volt cell, a MOSIS "tiny chip" and power
    transistors to drive the nitinol actuator wires.
    Alternatively, power and control can be supplied through a tether.

    A single robot costs between $10 and $30. The pro-rated cost of
    materials to construct robots in volume (200 or more) is less than
    $3. The design can be replicated to build complex arthropods, or
    colonies containing hundreds of insectoid robots.

    IUCS Technical Report 363a, "Stiquito: A Small, Simple,
    Inexpensive Hexapod Robot -- Part 1. Locomotion and Hard-Wired
    Control" contains detailed instructions to build the robot and a
    hard-wired, manually-operated controller. The instructions are
    illustrated with 80 life-sized figures that include dimensions and
    enlarged details. Materials, tools, and vendors are listed.
    Special sections include construction skills for novice users, how
    to fix mistakes, and troubleshooting problems found in real-world
    experience with the robot.

    Stiquito and its manual controller are assembled by crimping and
    press-fitting parts. No soldering is necessary. The resulting
    robot is very reliable. A tethered Stiquito walked for over 100
    hours. During the test each leg made 300,000+ 2-3mm strokes. The
    leg movement was reduced because power was supplied during the
    test by a 6v AC/DC adapter. With a 6v "J" battery typical leg
    movement is 3-7mm. Battery-powered leg movement was unchanged
    after the test.

    Anyone may build and use Stiquitos in any quantity for educational
    or research purposes, but Indiana University reserves all rights
    to commercial applications. Part 1 of the technical report is now
    available and can be obtained in two ways:


    Use anonymous ftp to obtain the technical report free. IU's
    ftp site is: (

    Log in as "anonymous" with username@host or "guest" as a

    I've split and compressed the PostScript & raw Word 4 files, and will
    do the same for the .hqx version if necessary. If you have problems
    with timeouts, our net guru, Bruce Sheu, has kindly offered to help.
    Send him mail at

    The reports are in /pub. Set the ftp mode to binary to access the Post-
    Script and raw Word 4 files: (restore with uncompress, cat)

    stiquito.w4.aa.Z (restore with uncompress, cat, uudecode
    stiquito.w4.ab.Z to get a MacBinary Word 4 document)

    stiquito.hqx (stuffed, binhexed Microsoft Word 4 for Mac)

    Unfortunately, some of the illustrations in the PostScript
    file print with minor errors (patterns missing, and some
    polygons deformed), but they are still understandable.

    2. BY MAIL (with options for a kit and a videotape)

    Send your request for the report with payment to:

    Computer Science Department
    215 Lindley Hall
    Indiana University
    Bloomington, Indiana, 47405, U.S.A.

    To receive the technical report only send $5 US PRE-PAID and
    add the following line to the address:

    ATTN: TR 363a

    To receive the technical report and a kit containing all
    materials needed to construct Stiquito and its manual
    controller send $15 US PRE-PAID. Add the following line to
    the address:

    ATTN: TR 363a Stiquito Kit

    The kit alone is available for $10 US PRE-PAID. Add the
    following line to the address:

    ATTN: Stiquito Kit

    The charges cover materials, a kitting fee, the technical
    report, and mailing. The kit is provided as a non-profit
    service by Indiana University. The author receives no fee or
    reimbursement from the sale of the kit.

    The CS department has also videotaped the assembly of a
    Stiquito (including the author making some mildly
    embarrassing mistakes during construction! :-). It is
    available separately for an additional $10 US PRE-PAID.
    Just add VIDEO to the attention line.

    For example, if you purchased the TR, kit, and video then
    $25 US would be enclosed and the following line would be
    added to the address:

    ATTN: TR 363a Stiquito Kit VIDEO

    Part 2 of the technical report, "Sensors and Controllers," is in
    preparation. It describes analog and digital controllers, legged
    Braitenburg vehicles, and sensor and communicatons interfaces to
    Stiquito. Part 3 of the technical report, "Experiments with
    Arthrobots," will describe a variety of arthropod robots and
    report on experiments in emergent cooperative behavior using a
    colony of Stiquitos.

    Questions about Stiquito should be sent to

    There are many different ways to design smaller, larger, or
    multiple-degree-of-freedom nitinol-propelled robots, legs,
    tentacles, grippers, etc. Some we've tried, most we haven't. We
    hope you will be encouraged to use Stiquito as a stepping-stone to
    better and more effective miniaturized robots.


    This research was funded in part by NSF Grant MIP-9010878
    "Lukasiewicz Logic Arrays" awarded to J.W. Mills, and NSF Grant
    CDA-8852304 "Incubator Laboratory Development" awarded to D.
    Gannon, G. Rawlins, and J. Smith. NSF's support is gratefully
    acknowledged. Standard disclaimer for opinions, etc. expressed in
    this posting.
    - J. W. Mills "Sic ago!"