Page 201 - Adaptive Identification and Control of Uncertain Systems with Nonsmooth Dynamics

Saturation Dynamics and Modeling 199

Figure 12.4 Diagram of typical flight control system.

12.4.2 Flight Control System

In the typical flight control systems as shown in Fig. 12.4, the sizing and
placement of control surfaces on an aircraft are determined by the per-
formance requirements [2,3]. In well-designed flight control systems, the
effect of saturation is generally of minimal impact by carefully addressing
the plant design and the closed-loop feedback control. However, there are
certain situations where the actuator saturation can become a problem in
operational flight control systems since the available control authority must
be properly allocated among the tasks at hand. For instance, dogfights and
aerial demonstrations at the boundary of the aircraft’s operational envelope
may require high-amplitude slewing maneuvers at the extreme edge of an
aircraft’s capabilities. Moreover, there is the quest for reconfigurable flight
control, which is driven by the need to accommodate failed control sur-
faces, where the saturation of actuators may become a problem in the event
of a control surface failure or when battle damage is sustained. Hence, the
compensation of saturation should be further considered in the control de-
signs to recover the system performance.

12.4.3 ITER Cryogenic System

ITER that is now under construction at Cadarache, France is designed to
demonstrate the scientific and technical feasibility of nuclear fusion as a pri-
mary source of virtually inexhaustible energy. It is the biggest fusion energy
research project, and one of the most challenging and innovative scientific
endeavors in the world today. The Tokamak under construction requires
high magnetic fields to confine and stabilize the plasma. For such a facil-
ity, a cryogenic system will be employed to cool-down and maintain the
superconductivity state of the magnets. The ITER cryogenic system [11]
will be one of the largest cryogenic systems in the world with a refrigera-
tion capacity of 65 kW equivalent at 4.5 K. In cryogenic systems, various
components (e.g., heat exchangers, valves, turbines, compressors, etc.) are