Increasingly demanding industrial applications
require fast and cheap computing tools
for real-time control. For example, high performance
industrial robotics would benefit
from fast and cheap computing, but fast structures
are generally expensive and dedicated to
particular tasks [ 1,2,3]. Another example
which requires fast computing is the control
of electrical transients of ac motors, where
complex numerical computations must be carried
out within times like 1 ms [4]. A recent
paper described implementation of a self-tuning
controller which uses a digital signal
processing chip for rapid calculations [5].
For many control applications there is a
natural hierarchical structure so that algorithms
devoted to simple tasks are placed at
the lowest level (for example, controlling a
robot axis or determining the switching time
of a static converter), whereas complex tasks
are at the high levels, forming a pyramidal
control structure which reflects the multilevel
structure described by Mesarovic [6].I n such
a structure, tasks are usually repetitive and
involve rapid manipulation of data, directly
derived from the measurements of sensors,
while high-level tasks are done over larger
time intervals with more complex algorithms.
This paper describes a computing structure
taking into account the hierarchical considerations
above. The architecture consists of a
high level general purpose computer (HOST)
and up to eight digital signal processors (DSPs) which can be interfaced with the controlled
plant(s).
The high-level computer is either a work
station or an advanced personal computer
with sufficient memory space (RAM and
mass memory), equipped with peripherals for
implementation of user-friendly interface and
with the ability to communicate with other
computers, perhaps in a local network. The
synchronization and the real-time communications
between the HOST and a DSP are
implemented by the two memory bank alternatively
switched between the HOST and the
DSP. A complete transparency and a minimum
overhead result for the tasks running on
the DSP
