INNOVATIVE APPROACHES TO ELECTROMECHANICAL FLIGHT CONTROL ACTUATORS AND SYSTEMS

This paper focuses on key challenges of electromechanical actuation systems with multiple degrees of freedom for two specific applications. One is an electromechanical fixed wing trailing edge flap actuation system enabling both differential and asymmetric flap setting for a transport aircraft. The second one is an electromechanical actuation system for the swashplate of a helicopter. To optimize the system weight, initial fit cost and MTBF of the trailing edge flap actuation system different system topologies are investigated. Further innovative approaches are invented for feedback sensors, electric motors, mechanical transmissions and control systems trying to take benefit from the specifics of the electromechanical actuators like their inherent positioning accuracy, high control bandwidth and speed independent torque limiting capability. The swashplate system of a helicopter provides lift, pitch and roll control. The loss of any of these control functions is classified catastrophic mandating a very robust and faulttolerant design of the 3-degree-of-freedom swash plate actuation system. Different architectures of such actuation system are presented that are fail-operative regarding major mechanical failures and dual-fail-operative for all other failure modes whose probability is not extremely remote. These architectures are evaluated in terms of technological risk, weight, and installation space.