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\F3\C154 EAST DANA STREET
\CMOUNTAIN VIEW, CA. 94041
Mr. T.J. Donnelly
Westinghouse Nuclear Division
P.O. Box 2728
R & D Center- Building 101
Pittsburgh, Pa. 15235
Dear Mr. Donnelly:
\J Vicarm is pleased to reply to your request for proposal for a
remote manipulator system suitable for use in the channel head and
tube plate area of your Westinghouse Nuclear Heat Exchanger.
Due to the extremely limited time we have had to prepare our
response, our present proposal will have to be brief and limited in
We have looked at two different approaches to your problem.
The first solution involves an enlarged version of our Model Stanford
Manipulator, mounted in, or next to the manway. The second approach
involves a smaller manipulator which travels on a fixed or semi-fixed
guide mounted within the channel head.
The First Solution.
The Vicarm model Stanford Manipulator is a six degree of
freedom computer controlled manipulator characterized by six
independent, D.C. motor powered joints. The manipulator can be
quickly separated into three sections. The shoulder section contains
two revolute joints, and the drive for the prismatic joint. The boom
section is a square aluminum tube with a rack mounted on one side.
This boom slips into the shoulder and engages the prismatic joint
drive pinion. The third section is the wrist section. This section
consists of three revolute joints with intersecting axes, and a hand
drive unit with provision for various terminal devices.
Each of these six joints plus the hand unit is an independent
servo system consisting of a D.C. motor, reducer, tachometer,
position feedback device (encoder, resolver or potentiometer), and
brake. Thus, the three sections are very simply mechanically and
electrically assembled into the complete manipulator. To meet your
requirements, Vicarm would first consider increasing the size of our
manipulator elements to meet your load specifications. Our current
manipulator employs the USM Harmonic Drive reducer. We have checked
their specifications and it appears practical to scale up our
manipulator to meet your load requirements. In addition, the natural
low tooth engagement velocity of this sort of dirve makes an oil free
drive system practical. We also see no reason to conisder anything
other than an all electric drive system, as your power (rate of work)
requirements are rather low. The high power to weight properties of
an hydraulic system would be of no benefit here.
The specification that the manipulator reach all points within the
channel head implies that all six degrees of freedom be located
within the head, or well into the manway. As we do not have
sufficient manway and channel head details, we have not done a
working volume study and are thus not able to dimension this proposed
manipulator at the present time.
A Second Alternative.
Because your access port is small relative to your working
volume, another approach may be taken. This system involves
installation of a removable track within the channel head. This may
either be a single tube or rail section mounted across the head, or a
perimeter section, going around the inside of the channel head.
Travelling on this track would be a small, strong manipulator unit
with multiple degrees of freedom. This unit would be attached to the
track and have to ability to move along the track, rotate around the
track and rotate relative to the track. By having this track
stationary (or with only a single rotational degree of freedom), a
lightweight sectioned support for the small manipulator could be
obtained. With this approach, the large moments involved in a
cantelevered manipulator system would be handled by a stationary
structure. The manipulator itself would merely have to handle the
required loads and limited offset moments. This design approach
would have to be done from scratch, as the manipulator system would
be more of a special purpose device rather than the general purpose
devices Vicarm currently produces.
Vicarm produces computer controlled manipulators. All our
manipulators are thus expressly designed for computer control. We
supply them with computer interfaces, with computer, and with
software, depending on the customer's desires. We offer a hardware
multimode servo system with computer selectable position, velocity,
and torque servo modes.
Our arms are solvable (not all current manipulators are!),
and we can provide solution programs, straight line motion routines,
trajectory programs, and other software to suit the application. Our
PDP-11 based system with links to the PDP-10 computer provides us
with very large compute power. We would definitely suggest a PDP-11
series computer for your applicatioj.
Our standard hand drive unit can mount different terminal
devices. We currently also offer a simple quickly changeable
terminal device based on a square drive and standard socket tools. A
variation of this unit may be suitable for your application. We also
offer touch and force sensing fingers, and a 6 component wrist mounted
force balance for precise force sensing and control.
What Vicarm can really do.
This proposal is very cursory, as has been our thinking
during this brief period. Vicarm is not currently financially
capable of undertaking a fixed price complete system contract. Nor
do we have the manpower to assure completion of such a project within
the approximately one year time frame you have suggested. Instead we
would prefer to offer our services in the area of manipulator design,
or subsystem design, either individually, or in cooperation with
other firms contracting with you on this project.
We look forward to hearing favorable news from you in the
near future and hope that in any event, you keep us in mind for other
manipulator related projects.\.