56 Robotics: Measuring 3 or 6DOF position part1
Description
This article is from the Robotics FAQ, by Kevin Dowling nivek@cs.cmu.edu with numerous contributions by others.
56 Robotics: Measuring 3 or 6DOF position part1
How do I measure the postion of my manipulator or my mobile robot?
In many applications there is a need to accurately measure the
position of an end-effector (hand or gripper) or find coordinate
locations on objects, or track motion, or give a time and position
history of a moving object. Virtual reality applications need this
kind of device to provide realtime adjustments to views that are
projected to VR users. See [41]sci.virtual-worlds for discussions on
this topic. Robotics people have needed this to provide accurate
assessments of manipulator motions and mobile robot positions.
An excellent paper on the subject of sensing and methods of using that
information is: "Where Am I? Sensors and Methods for Autonomous Mobile
Robot Localization." Technical Report, The University of Michigan
UM-MEAM-94-21, December 1994." It is a comprehensive survey on Mobile
Robot Positioning. This survey is over 200 pages long, has 130
illustrations and nearly 300 references, and took well over one
man-year to complete. The survey is entitled "Where Am I? Sensors and
Methods for Autonomous Mobile Robot Localization" A description and
table of contents can be found [42]here. To download the report go
[43]here and read [44]this file first. Alternatively, you can look at
a detailed Table of Contents from within Johann Borenstein's WWW
Homepage at: [45]Johann's Home Page Before you download the actual
survey, you should read the "readme.txt" file for compatibility tips,
and you should read the "um_index.wp5" file to see if you want to
download all or only selected chapters of the report. The Global
Positioning System (GPS) is an excellent positioning system that is
useful in outdoor settings, although recent developments in
Psuedolites (Pseudo Satellities) may bring GPS technology indoors and
to urban envrionments. While accuracy is intentionally degraded by the
US Military recent advances in differential systems and innovative
tracking techniques can give 20cm real-time accuracy. Even newer
techniques such as carrier-phase are bringing this figure into the mm
range for real-time. See [46]news:sci.geo.satellite-nav for full
discussions of this technology.
"Papers:" Useful papers to solve for transforms from positioning
devices for multiple reference frames:
* Roger Tsai and Rainer Lenz, IEEE Trans. on Robotics and
Automation, Jun 1989.
* C. C. Wang, IEEE Transactions on Robotics and Automation, April
1992. Useful papers for evaluating 3 ad 6 DOF human input devices:
* Shumin Zhai, Investigation of Feel for 6 DOF Inputs: Isometric and
Elastic Rate Control for Manipulation in 3D Environments, Proc.
Human Factors and Ergonomics Society 37th Annual Meeting,Seattle,
WA, October 1993.
* Shumin Zhai and Paul Milgram, Human Performance Evalulation of
Manipulation Schemes in Virtual Environments", Proc. Virtual
Reality Annual International Symposium, IEEE, Seattle, WA,
September 1993.
* Shumin Zhai and Paul Milgram, Human Performance Evalulation of
Isometric and Elastic Rate Controllers in a 6 DOF Tracking Task,
Proc. SPIE vol. 2057, Telemanipulator Technology", Boston, MA,
September 1993.
"Commercial Devices:"
"Blevins Enterprises "
tel: 208-885-3805
contact: Nick Sewell
Blevins writes their own utilities and sell 3D digitizers starting @
around $2,400 on up to around $75,000. Software is compatible with
Lightwave and 3D Studio modelling programs and will be ported to SGI
and PC's soon. Provide software to talk with Polhemus, a sonic
digitizer and a jointed-arm unit from Immersion.
"Cyberware "
8 Harris Court 3D
Monterey, CA 93940
tel: 408.373.1441
fax: 408.373.3582
Italian distributor:
91-22-6409-949
Has 3D scanner. Cyberware has software for editing 3D models, and
stitching multiple scans into a single coherent whole. Software is
$5-10K each. Cyberware 3030RGB/HIREZ scanner with MM motion platform,
complete with all software, training and one-year support costs [US]
$75,200.
"Eshed Robotics"
Eshed Robotec
Israel (HQ)
tel: 03-498136
fax: 03-498889
In the US
Eshed Robotec Inc.
445 Wall St.
Princeton, NJ 08540-1504
tel: 609.683.4884
tel: 800.777.6288
Eshed Robotec BV
Oude Torenweg 29
5388 RK Nistelrode
The Netherlands
tel: +31.412.611476
fax: +31.412.613185
net: [47]eshedbv@pi.net
url: [48]http://www.pi.net/~eshedbv/ and [49]http://www.eshed.com
Eshed's V-scope allows you to measure, record, process, and
demonstrate the motion of one or more bodies in one, two or three
dimensions. The V-scopeTM system uses tracking technology which
emits infrared signals to trigger ultrasonic response signals. This
technology allows full three-dimensional tracking within a space of
a few meters, with resolution of a fraction of a millimeter. See
[50]V-scope for more details.
"Intelligent Solutions Inc. "
One Endicott Avenue
Marblehead, MA 01945
tel: 617.639.8144
fax: 617.639.8144
net: isi@world.std.com
contact: Jim Maddox
Intelligent Solutions Inc. was formed in Nov. of 1993 by four of the
former engineers of Denning Mobile Robotics. They are focusing on
building smart sensors and their first product is the EZNav Position
Sensor. EZNav is a precision optical position sensor that can be
used on moving platforms such as automated guided vehicles, robots,
or material handling equipment. EZNav uses an eye safe scanning
laser with a 360 degree field of view to measure the azimuth angle
to wall mounted reference reflectors. This angle data can be used to
triangulate the position and heading relative to the known target
locations. EZNav is unique in its ability to use passive reflectors
as well as coded electronic targets. Current work includes adding
the triangulation calculations to the EZNav sensor and a new
Ultrasonic based position sensor.
Specs:
Target Range 30m passive up to 180m active
Abs. Accuracy +/- 0.03 degrees RMS
Scan Rate 12 per second
Data Rate 9.6k baud RS 232
Power 24 volts at 300 ma
Size 30cm Dia x 35cm High
Weight 4.5kg
An EZNav sensor with 10 passive targets costs $6,600. There is a ten
percent discount for educational uses.
"Kinetic Sciences"
3250 East Mall
Vancouver, BC, CANADA V6T 1W5
tel: 604.822.2144
fax: 604.822.6188
net: [51]info@kinetic.bc.ca
url:
[52]http://www.asi.bc.ca/asi/affiliates/kinetic/KSI_home_pg.html
Eagle Eye (TM) is a Power Macintosh application that accurately
tracks specially designed passive optical targets. It can track
multiple targets simultaneously in visually cluttered environments
using a single video camera. For each target that it can see, it is
able to determine seven parameters:
* the target's identity (via the information encoded on the marker);
* the target's position (X, Y, and Z with respect to the camera);
* the target's orientation (roll, pitch, and yaw with respect to the
camera).
The approach we have taken is particularly well suited to docking
and inspection applications. For further information, check out the
Eagle Eye web page at:
[53]http://www.asi.bc.ca/asi/affiliates/kinetic/KSI_Eagle_Eye.html
"NES North Electronic Systems S.p.A."
via Nazionale, 62
1-17043 CARCARE (SV), Italy
tel: +39-19-510420
fax: +39-19-512198 Distributed Local Positioning System (DLPS) is a
positioning system for indoor applications in a multi-robot
environment using active beacons with modulated light beams
(coherent red, non-coherent IR). The localization system also allows
communication by optical wireless links between hosts and robots.
The system utilizes and on-board rotating unit and a set of active
beacons distributed in the operating area. The active beacons are
optical transponders and, optionally, transceivers connected to a
IEEE 485 serial LAN.
Systems can operate up to 16m distance and with a localization
accuracy under 20mm in static and 70mm in dynamic localization. DLPA
was developed in cooperation with Laboratorium, DIST - University of
Genoa. email: sand@dist.unige.it, vercelli@dist.unige.it and URL
[54]website
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