System engineering approach for diagnostics of electromechanical systems

Complex electromechanical subsystems have a number of electrical and mechanical components that make it difficult to fault-isolate a failure. Some electromechanical subsystems are: engine controls (Full Authority Digital Engine Control-FADEC), Environmental Control System (ECS), Auxiliary Power Unit (APU), Air-Turbine Starter Set (ATSS), Electrical Power System (EPS), mechanical Flight Control System (includes hydraulics and servo-actuators), anti-skid brake system, traction control, Fuel subsystem and anti-collision system. These have a number of electrical and mechanical components that are difficult to fault-isolate This paper provides an overall system-level approach for the implementation of a Health Management Fault Isolator (HMFI). The HMFI can be applied to a number of different systems (products) which contain electromechanical systems (subsystems) that are difficult to fault-isolate. This paper focuses on systems related to aircraft however, other systems on ships, submarines, locomotives, trucks, power plants, office buildings, wind turbines, refineries, farm equipment, tanks and automobiles can also benefit from the Health Management Fault Isolator. There are some challenges in the implementation of the HMFI that have been discussed in this paper. The initial proposal for the HMFI project must include the complete life cycle cost for the system with HMFI and the complete life cycle cost for the same system without HMFI.