69 What's available for Puma Manipulators? (Robotics)
Description
This article is from the Robotics FAQ, by Kevin Dowling nivek@cs.cmu.edu with numerous contributions by others.
69 What's available for Puma Manipulators? (Robotics)
Pumas are probably the most common robot in university laboratories
and one of the most common assembly robots. Designed by Vic Schienman
and financed by GM at MIT in the mid-70's, the Puma (Programmable
Universal Machine for Assembly) was produced for many years by
Unimation (later purchased by Westinghouse and sold at a loss later to
Staubli, a Swiss company) These robots and their progeny are found in
many university labs.
Staubli Unimation, Inc.
201 Parkway West
Hillside Park
Duncan, SC 29334
tel: 803.433.1980
fax: 803.486.9906
Staubli Unimation Ltd
Unit G, Stafford Park 18
Telford, Shropshire, TF3 3Ax
UK
"PUMA singularities"
The PUMA has three singularities: the ``alignment'' singularity (wrist
is as close to the axis of joint 1 as it can get), the ``elbow''
singularity (elbow is fully extended or folded up; the latter is not
possible because of joint limits), and the wrist singularity (the axes
of joints 4 and 6 are aligned).
The angles corresponding to these depend on the Denavit-Hartenburg
(DH) parameter assignment. For the PUMA, the definitions given in [1]
are perhaps the most commonly used Using these, and letting A2, A3,
D3, and D4 denote the translational DH offsets, the singularities
occur when the following are true:
Alignment: D4*sin(ang2+ang3) + A2*cos(ang2) - A3*cos(ang2+ang3) == 0
Elbow: sin(ang3 - atan2(A3,D4)) == 0
Wrist: sin(ang5) == 0
Typical offset values for the PUMA 560 are
A2 = 431.80
D3 = 149.09
A3 = 20.32
D4 = 433.070
Information provided by John Lloyd [3]lloyd@curly.mcrcim.mcgill.edu
Puma Gear Ratios
Joint # Gear Ratio
-------- -----------
1 0.01597
2 0.00931
3 0.01884
4 0.01428
5 0.01391
6 0.01303
Puma Quirk
[Gary McMurray] There is an undocumented bug in the tool mode of the
PUMA robot under real-time path control. It's found by trying to
control the robot in tool mode using the alter command. Unimation
(Westinghouse at that time), has confirmed the bug.
Basically, the bug consists of this: during real-time control, such as
alter mode, the controller does not update the rotation matrix for the
tool coordinate system as the robot moves. Thus, motion commands
issued to move along the new y axis, result in a motion along the
original y axis. The same goes for rotations as well.
Tech Report and Matlab Toolbox
[Peter Corke] A technical report is available which provides details
of the Unimation Puma servo system, including details of interfacing
via the arm-interface board, digital board firmware, and analog
board/motor dynamics. (54 pages) It can be found at
[4]ftp://janus.cat.csiro.au/pub/pic/pumaservo.Z
A Robotics Toolbox for MATLAB which provides functions for homogeneous
transformations, quaternions, forward and inverse kinematics,
trajectories, forward and inverse dynamics, and graphical animation.
The Toolbox uses a very general method of describing the kinematics
and dynamics of any serial-link manipulators. Descriptors for the
Unimate Puma 560 and the Stanford arm are included. Location at
[5]ftp://ftp.mathworks.com/pub/contrib/misc/robot
That directory contains an extensive manual, doc.ps (72 pages), as
well as all the M-files.
"Trident Robotics and Research, Inc."
2516 Matterhorn Drive
Wexford, PA 15090-7962
tel: 412.934.8348
net: [6]robodude@cmu.edu
Hardware for older LSI/11 based Puma's.
A board for replacing the PUMA LSI/11 controller with the CPU of your
choice: The board is basically an I/O board with D/A's, A/D's, encoder
counters and some digital I/O lines and is available to connect to
several bus architectures including VMEbus, IBM-PC bus, Multibus and
IndustryPack bus. (with others under consideration) It comes as a
two-board set: A PUMA board and a bus interface board. This allows
several buses to be supported and keeps the analog electronics away
from the noise of the bus. (It also makes switching buses cheap, if
the need ever arises.) Since it is primarily an I/O board set, it can
be used in applications other than controlling a PUMA.
The user's manuals are available by anonymous ftp at
[7]ftp://ftp.cs.cmu.edu/usr/anon/user/deadslug/ and
[8]ftp://ftp.cs.cmu.edu/usr/anon/user/deadslug/
This is a PostScript file that can be printed or viewed (to conserve
paper) and describes the remote board that mounts inside the Unimate
controller, replacing the VAL computer. The file trd0001.ps shows the
board arrangement diagrammatically.
"Useful Puma references"
Richard Paul, Brian Shimano, and Gordon Mayer, "Kinematic Control
Equations for Simple Manipulators". IEEE Transactions on Systems, Man,
and Cybernetics, Vol SMC-11, No. 6, June 1981.
B Armstrong, O Khatib, and J. Burdick The Explicit Dynamic Model and
Inertial Parameters of the PUMA 560 Arm Proceedings IEEE Int.
Conference on Robotics and Automation, April 1986 San Francisco, CA
pp510-518
P.I. Corke and B. Armstrong-Helouvry. "A search for consensus among
model parameters reported for the Puma 560 Robot." Proc. IEEE Conf.
Robotics and Automation, 1994 pp. 1608-1613
It is also available via anonyous ftp from
[9]ftp://janus.cat.csiro.au/pub/pic/icra94.ps.gz
Continue to:
My Books
