System and method for improved start-up of self-oscillating electro-mechanical surgical devices

1. An oscillating circuit for determining a resonant frequency of an electro-mechanical oscillating device and for driving the electro-mechanical oscillating device at the determined resonant frequency, the oscillating circuit comprising:

a driving circuit configured to receive at least one reference signal and further configured to provide a driving signal related to the at least one reference signal to the electro-mechanical oscillating device, wherein the driving circuit determines a resonant frequency by measuring a parameter related to the resonant frequency of the electro-mechanical oscillating device;

a start-up, impetus injection circuit operably coupled to the electro-mechanical oscillating device, wherein the start-up, impetus injection circuit is configured to selectively provide a start-up excitation signal to the electro-mechanical oscillation device, and wherein the start-up, impetus injection circuit is activated upon start-up of the oscillating circuit to drive the electro-mechanical oscillation device; and

an excitation signal generating circuit including:

a DC voltage source; and

an energy storage device operatively coupled to the DC voltage source in a first condition and operatively coupled to the start-up switch in a second condition; and

a start-up switch configured to selectively couple the excitation signal generating circuit to the electro-mechanical oscillating device,

wherein in the first condition, the DC voltage source charges the energy storage device, and, in the second condition, the energy storage device drives the electro-mechanical oscillating device to a position related to a point of maximum amplitude.

2. The oscillating circuit of claim 1 , wherein the driving circuit determines a resonant frequency of the electro-mechanical oscillating device within one-half cycle of the resonant frequency.

3. The oscillating circuit of claim 1 , wherein the driving circuit determines a resonant frequency of the electro-mechanical oscillating device within three cycles of the resonant frequency.

4. The oscillating circuit of claim 1 , wherein the parameter is related to the resonant frequency and is related to motion of the electro-mechanical oscillating device.

5. The oscillating circuit of claim 4 , wherein the parameter related to the resonant frequency is selected from a group consisting of current, voltage and mechanical position.

6. The oscillating circuit of claim 1 , wherein the energy storage device includes a capacitor.

7. The oscillating circuit for determining a resonant frequency of an electro-mechanical oscillating device and for driving the electro-mechanical oscillating device at the determined resonant frequency, the oscillating circuit comprising:

a driving circuit configured to receive at least one reference signal and further configured to provide a driving signal related to the at least one reference signal to the electro-mechanical oscillating device, wherein the driving circuit determines a resonant frequency by measuring a parameter related to the resonant frequency of the electro-mechanical oscillating device;

a start-up, impetus injection circuit operably coupled to the electro-mechanical oscillating device, wherein the start-up, impetus injection circuit is configured to selectively provide a start-up excitation signal to the electro-mechanical oscillation device, and wherein the start-up, impetus injection circuit is activated upon start-up of the oscillating circuit to drive the electro-mechanical oscillation device; and

an excitation signal generating circuit including:

an digital-to-analog signal converter configured to generate a time-frequency varying driving signal operatively coupled to the start-up switch,

wherein the electro-mechanical oscillating device is driven by the time-frequency varying driving signal generated by the digital-to-analog signal converter; and

a start-up switch configured to selectively couple the excitation signal generating circuit to the electro-mechanical oscillating device.

8. The oscillating circuit of claim 7 , wherein the frequency of the time-frequency varying driving signal varies linearly with respect to time.

9. The oscillating circuit of claim 7 , wherein the frequency of the time-frequency varying driving signal varies exponentially with respect to time.

10. The oscillating circuit of claim 7 , wherein the driving circuit determines a resonant frequency of the electro-mechanical oscillating device within one-half cycle of the resonant frequency.

11. The oscillating circuit of claim 7 , wherein the driving circuit determines a resonant frequency of the electro-mechanical oscillating device within three cycles of the resonant frequency.

12. New The oscillating circuit of claim 7 , wherein the parameter is related to the resonant frequency and is related to motion of the electro-mechanical oscillating device.

13. The oscillating circuit of claim 12 , wherein the parameter related to the resonant frequency is selected from a group consisting of current, voltage and mechanical position.

14. A method for starting an electro-mechanical oscillating device, the electro-mechanical oscillating device having a varying resonant frequency, the method comprising the steps of:

generating a start-up excitation signal by activating a start-up switch coupling an excitation signal generating circuit to the electromechanical oscillating device, wherein the excitation signal generating circuit includes a DC voltage and an energy storage device such that the energy storage device is operatively coupled to the DC voltage source in a first condition and operatively coupled to the start-up switch in a second condition, wherein in the first condition, the DC voltage source charges the energy storage device, and, in the second condition, the energy storage device drives the electro-mechanical oscillating device;

applying the start-up excitation signal to the electro-mechanical oscillating device;

driving the electro-mechanical oscillating device to a position related to a point of maximum amplitude;

removing the excitation signal from the electro-mechanical oscillating device when the electro-mechanical oscillating device is at a position related to the point of maximum amplitude;

measuring at least one parameter related to a resonant frequency of the electro-mechanical oscillating device;

determining a resonant frequency of the electro-mechanical oscillating device; and

driving the electro-mechanical oscillating device at the determined resonant frequency.

15. The method of claim 14 , wherein the at least one parameter is selected from the group consisting of current, voltage and mechanical position.

16. A method for starting an electro-mechanical oscillating device, the electro-mechanical oscillating device having a varying resonant frequency, the method comprising the steps of:

generating a time-frequency varying start-up excitation signal by activating a start-up switch coupling a excitation signal generating circuit to the electromechanical oscillating device, wherein the excitation signal generating circuit includes a DC voltage and an energy storage device such that the energy storage device is operatively coupled to the DC voltage source in a first condition and operatively coupled to the start-up switch in a second condition, wherein in the first condition, the DC voltage source charges the energy storage device, and, in the second condition, the energy storage device drives the electro-mechanical oscillating device;

applying the time-frequency varying start-up excitation signal to the electro-mechanical oscillating device;

driving the electromechanical oscillating device to a position related to a point of maximum amplitude;

measuring at least one parameter related to a resonant frequency of the electro-mechanical oscillating device while driving the electro-mechanical oscillating device with the time-frequency varying excitation signal;

determining the resonant frequency of the electro-mechanical oscillating device; and

driving the electro-mechanical oscillating device at the determined resonant frequency.

17. The method of claim 16 , wherein the at least one parameter is selected from the group consisting of current, voltage and mechanical position.

18. A method for starting an electro-mechanical oscillating device, the electro-mechanical oscillating device having a varying resonant frequency, the method comprising the steps of:

generating a start-up excitation signal by activating a start-up switch coupling an excitation signal generating circuit to the electromechanical oscillating device, wherein the excitation signal generating circuit includes a digital-to-analog signal converter configured to generate a time-frequency varying driving signal operatively coupled to the start-up switch, such that the electro-mechanical oscillating device is driven by the time-frequency varying driving signal generated by the digital-to-analog signal converter;

applying the start-up excitation signal to an electro-mechanical oscillating device;

driving the electro-mechanical oscillating device to a position related to a point of maximum amplitude;

removing the excitation signal from the electro-mechanical oscillating device when the electro-mechanical oscillating device is at a position related to the point of maximum amplitude; measuring at least one parameter related to a resonant frequency of the electro-mechanical oscillating device;

determining a resonant frequency of the electro-mechanical oscillating device; and

driving the electro-mechanical oscillating device at the determined resonant frequency.

19. The method of claim 18 , wherein the at least one parameter is selected from the group consisting of current, voltage and mechanical position.

20. A method for starting an electro-mechanical oscillating device, the electro-mechanical oscillating device having a varying resonant frequency, the method comprising the steps of:

generating a time-frequency varying start-up excitation signal by activating a start-up switch coupling an excitation signal generating circuit to the electromechanical oscillating device, wherein the excitation signal generating circuit includes a digital-to-analog signal converter configured to generate a time-frequency varying driving signal operatively coupled to the start-up switch, such that the electro-mechanical oscillating device is driven by the time-frequency varying driving signal;

applying the time-frequency varying start-up excitation signal to an electro-mechanical oscillating device;

driving the electro-mechanical oscillating device to a position related to a point of maximum amplitude;

measuring at least one parameter related to a resonant frequency of the electro-mechanical oscillating device while driving the electro-mechanical oscillating device with the time-frequency varying excitation signal; and

determining the resonant frequency of the electro-mechanical oscillating device; and driving the electro-mechanical oscillating device at the determined resonant frequency.

21. The method of claim 20 , wherein the at least one parameter is selected from the group consisting of current, voltage and mechanical position.