Closed loop control systems employing relaxor ferroelectric actuators

A method of controlling an electromechanical actuator system, the method comprising the steps of:

• applying an electric field to an actuator body formed from a relaxor-based material to generate a piezoelectric movement in the actuator body;
• in response to the piezoelectric movement of the actuator body, producing a phenomenon in a mechanical system;
• sensing the phenomenon produced by the mechanical system;
• and
• varying the applied electric field according to the outcome of the sensing step.

An electromechanical actuator system, comprising:

• an actuator device having an actuator body formed from a relaxor-based piezoelectric material and a mechanical system driven by the actuator body;
• a driver for variably applying an electric field to the actuator body;
• and
• a feedback loop for providing input to the driver in response to at least one phenomenon produced by the mechanical system.