Design solutions for modern engineering systems
have reached a degree of maturity where reliance upon
active control systems, to satisfy an array of objectives,
is common place and often necessary.l For example, in
advanced fighter aircraft concepts, the vehicle is
expected, under the commands from the pilot, to rapidly
transition between pre-stall and post-stall flight
conditions. Sluggish responses with severe coupling in
the rolllpitchlyaw axes are a direct result of operating in
this high angle of attack and high angular rate
environment. Multivariable control laws are necessary
to augment the vehicle characteristics to exhibit well
coordinated responses extolling high levels of damping,
quickness, and robustness, when contrasted against
established handling quality criteria.
Restoring exceptional handling qualities to the
vehicle requires a method to synthesize multiple
feedback and crossfeed paths. These signal paths must
work in a coordinate fashion, providing operation at
near maximum performance levels with stability
margins approaching minimum requirement limits.
Desirable attributes of any proposed design technique
should include 1) clear and concise relationships