The present invention provides a system for engaging a fluid flow. The system comprising one or more foil members operationally connected to a feedback control loop system. In one embodiment, the foil member is a hydrofoil member or an airfoil member. The foil members are configured for one or more degrees of freedom of oscillatory movement within the fluid flow. The feedback control loop system comprises a sensor system, actuator system, and a controller system. The feedback control loop system configured for actuating the foil members and thereby optimizing the operation of the foil members to attain one or more optimization objectives. In operation, the foil members are situated in the fluid flow and are manipulated to attain one or more optimization objectives.