Compact Electrohydraulic Actuator Powerpacks for Distributed Drives – Configuration, Controls and System Performance 2002-01-1457

Small electro-hydraulic actuators have started to replace systems with centralized hydraulic power supply in some areas. Therefore the most common systems with a variable speed electric motor in combination with a fixed-displacement pump and a constant speed motor with a variable displacement pump were compared using the load cycle of the aileron of a civil aircraft. For this load cycle the configuration with fixed displacement pump and the variable speed electric motor showed the same dynamic and a much better energetic performance than the variant with a constant speed motor and a variable displacement pump. The energy consumption could be reduced by 55 % using the motor speed as the control input. With a logic that changes the control input between motor speed and swashplate angle as a funktion of the actual motor speed the energy consumption could be reduced by another 24 %.