Hybrid Computing at Lockheed
Hybrid Computing
At Lockheed
CONTROL DATA
CORPORATION
APPLICATION REPORT
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SRA EES eee.
HYBRID COMPUTING AT LOCKHEED
When the advanced Poseidon missile goes
into service aboard the U. S. Navy’s Fleet
Ballistic Missile submarines, another suc-
cessful chapter will have been written in
the history of hybrid computing.
In the hybrid computing laboratory at
Lockheed Missiles and Space Company,
Sunnyvale, California, a powerful digital /
analog computer complex is being used to
test the guidance and control mechanisms
of the Poseidon missile. With a CONTROL
DATA® 6400 Computer at the heart of the
system, simulation of actual operating
conditions is performed mathematically,
data from test laboratories is collected and
analyzed, and various alternatives are ex-
plored. Thus, Lockheed engineers are able
to achieve an optimum design at a frac-
tion of the time and cost that would be
consumed by multiple live test-firings.
The installation at Lockheed is one of the
most versatile hybrid systems in existence.
It gives Lockheed personnel the ability to
perform both man-in-the-loop and closed-
loop simulations at whatever speeds are
desired. It provides designers and analysts
with an unprecedented degree of control
over testing and simulation. And, through
an adaptable hardware/software struc-
ture, it is capable of modification to ac-
commodate new hybrid—and digital —
tasks.
THE SYSTEM
CER SNS TS
Hybrid computation at Lockheed began
in 1964 with a CONTROL DATA® 3200 com-
puter system and two analog computers.
Successful performance on the Polaris
Missile System contract led to Lockheed’s
involvement in refitting FBM submarines
with Poseidon missiles.
A new, more powerful computer system
was needed to handle new and extremely
complex calculations. The choice for the
digital portion of the hybrid computer was
the CONTROL DATA 6400.
Among the factors leading to the choice
of the 6400 were its great computational
speed, multiprocessing organization, ex-
tensive input/output capability, and the
adaptability of its standard software. The
Lockheed system contains 32K words of
core memory, plus these standard Control
Data peripherals: two 604 Magnetic Tape
Units; one 6603 Disk Storage Drive; one
501 Line Printer; one 415 Card Punch;
and one 405 Card Reader. (See Figure 1).
Four Comcor Ci5000 analog computers
are connected to the 6400 through two
interface units providing 160 channels of
analog-to-digital conversion capability.
Five CONTROL DATA® 211 Entry/Display
units provide on-line communication be-
tween the user and his problem. A 211
is located at each of the four analog com-
puters; the fifth 211 is associated with the
6400 itself. Completing the equipment ar-
ray are twelve X-Y plotters and twelve
8-channel strip chart recorders.
Sa A
OPERATION
Figure 2 illustrates the laboratory config-
uration at Lockheed. The system provides
for three stages of hybrid computation.
1. The most basic application makes use
of the computer system alone to simulate
missile flight. For example, the 6400 calcu-
lates the simulated position of the missile
in space, providing the logic for decision-
making, high-precision mathematical cal-
culations, and storage of variables and
results. The analog portion simulates on-
board mechanisms and missile attitude,
using high-speed parallel-processing to
solve the time-dependent differential
equations.
2. The second level of computation brings
into play the actual Poseidon hardware
and other mechanisms located in the vari-
ous adjacent laboratories. Activation of
this equipment, which is connected to the
hybrid computer system, provides a basis
for comparing simulated performance
with pre-programmed conditions.
The Guidance Laboratory, for example, is
equipped with one 3-axis flight table to
which are attached actual missile hard-
ware such as gyros and accelerometers.
Missile data generated by these mech-
anisms (speed, location, etc.) is sent to the
analog computer, where the desired con-
ditions have been programmed. Data is
also sent to a smaller digital guidance
computer, which in turn presents com-
mands to the 6400. The 6400 notes any de-
viations and outputs corrective signals
to the hardware devices responsible for
making adjustments in the flight. All
decision-making and bookkeeping jobs
are performed by the 6400, whose ten
peripheral processors easily handle all
system overhead (signal conversion, in-
terrupt processing, etc.), freeing the cen-
tral processor for vital calculating tasks.
In the Hydraulic Actuation Laboratory,
aerodynamic loads are simulated by hy-
draulic, pneumatic, and electrical means
on the after section of the missile. Test
data is sent to the hybrid computer system
where it is analyzed and adjustments are
made.
3. The third and final stage of Poseidon
testing will take place at Lockheed’s
Santa Cruz test base, 60 miles from the
computer center. Communication between
ify
One of the four analog computers with associated
CDC® Entry/ Display.
The CDC® 6400 Computer, center of the Lockheed
hybrid system.
the two sites will be via closed-loop micro-
wave. The Poseidon will undergo tied-
down, static firing tests, with the hybrid
computer system again analyzing test
data. The system will simulate the actual
flight conditions so that in case of failure
the problem can be quickly isolated and
corrected.
On-Line Control
One of the outstanding features of the hy-
brid system at Lockheed is the degree of
hands-on control that the analyst can
exercise over both the digital and analog
operations. When seated at the analog
computer console, the analyst also has
at his fingertips a CONTROL DATA 211
Entry/Display unit. Through this device
he may interact with his program under
real-time conditions. He may:
® view program results which have been
converted to digital form.
e enter and modify variables and para-
meters.
* proceed through a problem at his own
rate of speed; halt his program to ana-
lyze immediate results, while 6400 core
memory is released for other jobs.
e enter programs for checkout and pre-
ventive maintenance of the digital, ana-
log, and interface elements of the system.
¢ perform on-line debugging of FORTRAN
programs.
¢ call up a historical file containing all
information pertinent to his particular
job.
Manipulating Time
A distinct advantage of the Lockheed
hybrid system is its ability to ‘‘scale”
time according to the demands of a par-
ticular problem. Computer simulations
may be conducted in real-time, faster
than real-time, or slower. For example,
an analog simulation may be slowed to
permit extended study of data. Time may
also be condensed for long-running pro-
grams without sacrificing accuracy. How-
ever, when actual flight hardware is in-
corporated in the simulation, the entire
computer must operate in real-time, (i.e.
there must be a one-to-one correspon-
dence to the ‘‘clock on the wall.’’)
|
SOFTWARE
As in any successful computer operation,
the computer hardware in Lockheed’s
hybrid laboratory is controlled by a power-
ful, versatile set of programs. The soft-
ware utilizes Control Data’s 6000 Series
“Scope” operating system, modified for
real-time hybrid computing.
Known as CLASH, the Lockheed System al-
lows simultaneous processing of two hybrid
problems, while standard digital jobs are
run as background tasks. The system con-
tains a Main Monitor and a Hybrid Moni-
tor. Under the Main Monitor are run stand-
ard jobs such as FORTRAN programs,
utility routines, and diagnostics, while the
Hybrid Monitor controls the real-time
simulation. The Hybrid Monitor (to which
the Main Monitor is subservient) responds
to interrupts — a total of 48 — and controls
the execution of jobs on a priority-
determined basis. The Exchange Jump
instruction in the 6400 computer provides
a fast, efficient method of switching from
one job to another.
Other elements of the software system
include: Special calculation packages;
hybrid utility routines; a “Dayfile’ which
keeps a running record of job progress
to be referenced at will; and a special
diagnostic routine that allows daily pre-
ventive maintenance of the entire hybrid
computer (analog, interface, and digital)
to be completed in two hours —a short
time for such a large system. Manual
checkout of the analog and interface
would take more than ten hours per day
without the 6400 — an impossible situation.
The capabilitits of 6400 hardware and
software will also permit batch-processing
jobs to be run without endangering or im-
peding the hybrid computation.
A GIANT STEP FORWARD
The Lockheed hybrid computer system
amplifies human capabilities to new
heights of effectiveness. The reasons can
be stated simply:
e Relationship between man and machine
is made closer than ever before through
the use of CDC® display devices. Prob-
lem setup, checkout, and running can be
controlled every step of the way.
The software system permits the analog
user (whose digital experience may be
limited) to utilize his full complement of
analog techniques and experience while
adding new digital techniques.
The speed and multiprocessing capa-
bility of the 6400 permits fast through-
put of problems whose requirements
may differ widely.
The 6400 can readily interface with a
great number of peripheral devices, in-
cluding analog equipment of various
makes, so that expansion and modifi-
cation can be accomplished with little
difficulty.
Simulation and other forms of hybrid com-
puting are taking on an ever-increasing
importance in many areas — space and de-
fense, scientific laboratories, industry, and
education. The system at Lockheed is in
the forefront of the hybrid movement,
solving problems that would be difficult
or impossible to handle by any other
means.
FIGURE 1
CONTROL DATA
6400
COMPUTER
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FIGURE 2
HYDRAULIC
ACTUATION
LABORATORY
RECORDERS
PLOTTERS
CDC 211 ENTRY/ DISPLAY
PERIPHERAL
EQUIPMENT
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