Patent ID: 8621756

Claim:
A smart material actuator apparatus comprising a smart material actuator having a natural resonant frequency, said smart material actuator comprising a mechanical amplifier comprising a substantially rigid fixed supporting member having a first mounting surface, a mechanical web attached to said fixed supporting member said mechanical web comprising a movable supporting member having a second mounting surface substantially parallel to said first mounting surface and at least one compliant member, and at least one actuating arm attached to said mechanical web; said smart material actuator further comprising a piezoelectric stack affixed between said first mounting surface and said second mounting surface such that substantially upon application of an electrical potential to said piezoelectric stack, said piezoelectric stack expands substantially without angular movement thereby urging said second mounting surface away from said first mounting surface, thereby causing said compliant member to flex, thereby moving said actuating arm; and a sensor adapted to generate a sensor signal proportional to the degree of movement of said actuating arm; said smart material actuator apparatus further comprising a controller electrically connected to said piezoelectric stack and said sensor, said controller being adapted to apply a power signal to said piezoelectric stack, said power signal having a power signal frequency and a power signal voltage; to determine a phase angle between said power signal and said sensor signal and compare said phase angle to a predetermined phase angle range; to adjust said power signal frequency in a first direction substantially upon determining said phase angle to be below said predetermined range; adjusting said power signal frequency in a second direction opposite to said first direction substantially upon determining said phase angle to be above said predetermined range; said predetermined range comprising the natural resonance phase angle; whereby said controller is adapted to operate said smart material actuator in a resonant condition.