Ultrasonic transducer control method and system
First Claim
1. A method of velocity control comprisinga) determining a non-motional clamped characteristic of a piezoelectric transducer at two predetermined frequencies, one below and one above a resonance frequency of the transducer;
- b) determining a correction factor based on the non-motional clamped characteristic at the two predetermined frequencies; and
c) applying the correction factor to generator output currents to maintain a specified value of end effector velocity.
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Accused Products
Abstract
The present invention relates to methods for velocity control of transducers that can compensate both for age related changes as well as the more immediate changes that occur during operation. In one aspect of the invention, the non-motional reactive current is measured at two predetermined frequencies, one below (Ilf) and one above the resonance frequency (Ihf). A correction factor is calculated from these measured currents is used to maintain a specified value of end effector velocity or displacement. In another aspect of the invention, methods are provided for the detection of secondary resonances that could be indicative of end effector fault conditions. In another aspect of the invention, velocity control is achieved.
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Citations
15 Claims
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1. A method of velocity control comprising
a) determining a non-motional clamped characteristic of a piezoelectric transducer at two predetermined frequencies, one below and one above a resonance frequency of the transducer; -
b) determining a correction factor based on the non-motional clamped characteristic at the two predetermined frequencies; and c) applying the correction factor to generator output currents to maintain a specified value of end effector velocity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification