An electromechanical actuator (EMA) is used to drive a lock/unlock mechanism to properly function an unpressurized door structure.
The customer sought an improvement to system reliability and the elimination of the potential of hydraulic fluid leaking into the crew cabin. An EMA solution was needed to replace the current hydromechanical design used on prior versions of the aircraft. The door lock actuator must operate under electrical power and in manual mode in the event of a power loss. Under power, the door lock actuator must drive the lock linkage and compress door seals to proper deflection.
The clean sheet EMA was designed to satisfy the mechanical loads, stroke, and velocity needed to operate the door lock mechanism. The actuator structural loads are a combination of the mechanism loads from lock linkages, seal compression forces, and the magnitude of aerodynamic forces developed on the door from rotor disk air flow and the impinging ambient air flow velocities during ground operations. The EMA must report status to the crew station annunciator light panels. Actuator performance is controlled by the Ingenium Aerospace defined Circuit Card Assembly (CCA). An electromechanical clutch is used within the mechanical drive train to provide the manual override capability. This design concept allows the EMA to be manual back driven with minimal amount of external force. Dynamic, mechanical overtravel stops are included in the EMA and are used to respond to excessive travel whether generated from manual force or aerodynamic loading.
Other design considerations for this actuator design solution included the acoustic noise level, electromagnetic interference (EMI), and lightning strike requirements.
Results & Outcome
Actuators have started Qualification and Environmental tests regimen. Initial test results have matched closely to analysis and predictions.