Dual redundant electrohydraulic actuation system

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In the past two decades, it has become painfully clear to the North American transportation industries that reliability is a key success criterion in their market sector. The growth of Toyota in the automotive sector and the demise of McDonald Douglas in the aerospace are testimonies to the importance of reliability in gaining/losing market share. In the past two years, Toyota has become the largest car manufacturer in the world by establishing itself a reputation for producing reliable cars that are competitively priced; McDonald Douglas on the other hand was taken over by Boeing Aerospace in the mid 1990s and its commercial-airline product-line virtually disbanded due to reliability problems with some of their aircraft. Other manufacturers have also come to appreciate and experience the need for product reliability on their business operations; Ford is a notable example. A reliable system can be viewed as one that has fewer breakdowns and operates according to an expected specification. Ultimately, reliability in a system is achieved by design; nonetheless, an equally strong factor that influences the overall perception of reliability is the capability of predicting and preventing failures by unscheduled maintenance to ensure operational reliability; this being particularly important to industries involved in mass production or transportation. Furthermore, preventing failures will have a very favorable impact on safety, operating costs, customer satisfaction, and ultimately market share. Prognostics and Health Monitoring Systems (PHMS) are advanced tools that are used for the detection, prognosis, and tracking of faults conditions. This proposal pertains to the development of an extended form of PHMS that will be capable of the diagnosis of fault conditions and the prediction failure conditions before their occurrence. This system will be based on a new theory proposed by the applicant referred to as the Smooth Variable Structure Filter (SVSF). It is to be tested on an actuation system that has been extensively researched by the applicant referred to as the ElectroHydraulic Actuator (EHA) that is of considerable interest to the aerospace sector.