Appeal No. 1996-1922
Application 08/110,506
control in the particular region of operation. In this manner, fuzzy control can be provided which
assures stability in the high process gain region indicated by numeral II without sacrificing performance
in the low process gain regions indicated by numeral I and III of Figure 2a. Fuzzy control systems that
utilize conventional fuzzy logic controllers do not make use of an auxiliary variable signal 46 and
therefore cannot differentiate between operation at different points in the process non-linearity.
The Prior Art
The Aoki reference discloses a method and apparatus for controlling a process having
latency or dead time. The latency or dead time occurs between a process input u and a process output
x. A fuzzy predictor is used to predict the process output for variation Îx occurring upon lapse of dead
time L by a fuzzy inference. The fuzzy inference is based on the process input u, process output x, and
a known disturbance d and other prior information. The predicted or inferred process output variation
Îx is then used to compute an error function u(e) and a change in error function u(e) occurring upon
lapse of dead time L. A conventional fuzzy proportional and integral controller 2 utilizes this error value
u(e) and change in error value u(e) to infer a process input signal u for the dead time process 4.
Opinion
After consideration of the positions and arguments presented by both the examiner and
the appellants, we have concluded that the rejection should not be sustained.
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