Self-latching piezocomposite actuator

A method of controlling the shape of a structure capable of defining at least first and second shapes, the method comprising:

• providing a self-latching piezocomposite actuator comprising a plurality of aligned shape memory ceramic fibers defining first and second strain states;
• operably connecting the self-latching piezocomposite actuator to the structure;
• changing the strain state of the shape memory ceramic fibers from the first strain state to a second strain state by applying a first electrical field to the shape memory ceramic fibers such that the shape of the structure changes from the first shape to the second shape;
• removing the first electrical field after the fibers are in the second strain state, wherein the actuator continues to maintain the structure in the second shape after the first electrical field is removed;
• applying a second electrical field to the shape memory ceramic fibers to cause the shape memory ceramic fibers to change from the second strain state to a third strain state that is between the first and second strain states or equal to the first strain state, and wherein the structure defines a third shape corresponding to the third strain state that is between the first and second shapes or the same as the first shape, wherein the second electrical field has a reverse polarity relative to the first electric field;
• maintaining the structure in the third shape by removing the second electrical field to maintain the shape memory ceramic fibers of the actuator in the third strain state.

A method of controlling a self-latching piezocomposite actuator, the method comprising:

• providing a self-latching piezocomposite actuator comprising a plurality of aligned shape memory ceramic fibers defining first and second strain states and a plurality of intermediate strain states between the first and second strain states;
• determining a required intermediate strain state of the shape memory ceramic fibers corresponding to a required shape of a structure incorporating the actuator;
• determining a present strain state of the shape memory ceramic fibers;
• changing the strain state of the shape memory ceramic fibers from the present strain state to the required intermediate strain state by applying an electrical field to the shape memory ceramic fibers;
• removing the electrical field after the fibers are in the required strain state, and wherein the shape memory ceramic fibers remain in the required strain state.