Page 33 - The Mechatronics Handbook

FIGURE 2.5 Advanced intelligent automatic system with multi-control levels, knowledge base, inference mecha-
nisms, and interfaces.

for maintenance or even redundancy actions, economic optimization, and coordination. The tasks of the
higher levels are sometimes summarized as “process management.”

Special Signal Processing

The described methods are partially applicable for nonmeasurable quantities that are reconstructed from
mathematical process models. In this way, it is possible to control damping ratios, material and heat
stress, and slip, or to supervise quantities like resistances, capacitances, temperatures within components,
or parameters of wear and contamination. This signal processing may require special filters to determine
amplitudes or frequencies of vibrations, to determine derivated or integrated quantities, or state variable
observers.

Model-based and Adaptive Control Systems

The information processing is, at least in the lower levels, performed by simple algorithms or software-
modules under real-time conditions. These algorithms contain free adjustable parameters, which have
to be adapted to the static and dynamic behavior of the process. In contrast to manual tuning by trial
and error, the use of mathematical models allows precise and fast automatic adaptation.
The mathematical models can be obtained by identification and parameter estimation, which use the
measured and sampled input and output signals. These methods are not restricted to linear models, but
also allow for several classes of nonlinear systems. If the parameter estimation methods are combined
with appropriate control algorithm design methods, adaptive control systems result. They can be used
for permanent precise controller tuning or only for commissioning [20].

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