Most real physical systems are nonlinear in nature. Control and ?ltering of nonlinear systems are still open problems due to their complexity natures. These problem becomes more complex when the system s parameters are - certain. A common approach to designing a controller/?lter for an uncertain nonlinear system is to linearize the system about an operating point, and uses linear control theory to design a controller/?lter. This approach is successful when the operating point of the system is restricted to a certain region. H- ever, when a wide range operation of the system is required, this...

The autopilot system which integrates the electronic hardware and the control algorithms has become standard use for commercial and military marine vessels, and is becoming essential equipment for smaller marine vessels such as leisure boats and yachts.