A smart embedded control unit for electro-hydraulic aircraft actuators

The design and experimental characterization of a novel electronic control unit for fly-by-wire aircraft actuators are presented. Thanks to a carefully-engineered compact volume, it is embedded in the actuator body, providing local closed-loop control. Various digital control laws can be implemented in the easily reconfigurable digital platform. After system modeling and tuning, a variable-gain controller has been selected. Beyond reduction of weight (900g), power dissipation (7W) and cabling connections (required only for power supply and digital communication bus), the advantages provided by this smart unit are both in terms of performance and safety improvement. In fact, fast (1Hz) and precise (1mm resolution, 2mm accuracy, no overshoot) closed-loop linear displacement regulation is here demonstrated. Furthermore, this robust and rugged unit is endowed with self-diagnostic capabilities: fault detection of all critical electronic and electro/mechanical sections is implemented by dedicated analog circuits. It is suitable for fully-electrical and hybrid electro-hydraulic actuators. Extensive thermal characterization has confirmed the fulfillment of specifications over the whole -40°C ÷ +70°C operating range.