On-demand fluidics system control based on frequency-domain processing
Frequency-domain signal processing of pressure sensor signals and/or flow signals is used to provide on-demand control of a multi-component fluidic system. An example method, implemented in a phacoemulsification system comprises receiving a signal from each of one or more sensors, the one or more sensors comprising at least one pressure sensor, and converting each of one or more of the received signals, including at least one signal from a pressure sensor, to a frequency-domain representation of the received signal. The method further comprises identifying, based on the frequency-domain representations of received signals, at least one event from a set of predetermined events, and controlling one or more fluid control devices, responsive to the identifying.
1. A control system for a phacoemulsification system, the control system comprising:
one or more sensors, the one or more sensors comprising at least one pressure sensor;
one or more fluid control devices; and
controller circuitry operatively coupled to the one or more sensors and the one or more fluid control devices and programmed to:
receive a time-domain signal from each of the one or more sensors, the time-domain signal having a magnitude, wherein the magnitude of the time-domain signal when detecting a surgical event is similar to a magnitude of the time-domain signal caused by a user's interaction with the phacoemulsification system or noise in the time-domain signal;
convert each of the one or more of the received time-domain signals to a frequency-domain representation of the received time-domain signal, said one or more of the received time-domain signals comprising at least one time-domain signal from a pressure sensor, said frequency domain representation comprising frequency and/or phase information of the received time-domain signal, wherein the frequency and/or phase information distinguishes the surgical event from the user's interaction with the phacoemulsification system or from noise in the system;
identify, based on the frequency-domain representations of received time-domain signals, at least one event from a set of predetermined events by evaluating the frequency and/or phase information of the frequency representation of the received time-domain signal; and
control one or more fluid control devices, responsive to said identifying.
2. The control system of claim 1 , wherein the controller circuitry is programmed to identify the at least one event based on detecting that a change, over time, in the frequency-domain representation of at least one of the received time-domain signals meets one or more predetermined criteria.
3. The control system of claim 1 , wherein the controller circuitry is programmed to identify the at least one event based on detecting that a difference between a predetermined baseline pattern and the frequency-domain representation of at least one of the received time-domain signals meets one or more predetermined criteria.
4. The control system of claim 1 , wherein:
the one or more sensors comprise a fluid flow sensor; and
the controller circuitry is programmed to convert the time-domain signal from the fluid flow sensor to a corresponding frequency-domain representation and to identify the at least one event based on the frequency-domain representation of the time-domain signal from the fluid flow sensor.
5. The control system of claim 1 , wherein:
the one or more sensors comprise a pressure sensor disposed in a phacoemulsification hand-piece and configured to monitor a pressure in an irrigation or aspiration conduit of the phacoemulsification hand-piece; and
the controller circuitry is programmed to convert the time-domain signal from the pressure sensor disposed in the phacoemulsification hand-piece to a corresponding frequency-domain representation and to identify the at least one event based on the frequency-domain representation of the time-domain signal from the pressure sensor disposed in the phacoemulsification hand-piece.
6. The control system of claim 5 , where the controller circuitry is programmed to identify a post-occlusion surge event, based on the frequency-domain representation of the time-domain signal from the pressure sensor disposed in the phacoemulsification hand-piece.
7. The control system of claim 1 , wherein:
the one or more sensors comprise two pressure sensors disposed at two points along an irrigation path in the phacoemulsification system;
the controller circuitry is programmed to convert the time-domain signals from each of the two pressure sensors to corresponding frequency-domain representations and to identify the at least one event based on the frequency-domain representations of the time-domain signals from the two pressure sensors.
8. The control system of claim 7 , wherein the controller circuitry is programmed to identify a change in flow resistance of the irrigation path based on the frequency-domain representations of the time-domain signals from the two pressure sensors.
9. The control system of claim 1 , wherein the controller circuitry is programmed to control at least one of the following, responsive to identifying the at least one event:
a fluid valve in an irrigation path;
a valve in an aspiration path;
a pressurizing device configured to selectively decrease or increase a pressure in an irrigation path; and
a pressurizing device configured to selectively decrease or increase a pressure in an aspiration path.
10. The control system of claim 1 wherein the controller circuitry is programmed to identify a post-occlusion surge event based on the frequency-domain representation of the time-domain signal.
11. The control system of claim 1 wherein the controller circuitry is programmed to identify a fluid flow change, based on the frequency-domain representation of the time-domain signal.
12. The control system of claim 1 wherein the controller circuitry is programmed to evaluate and characterize frequency and/or phase characteristics of noise in the time-domain signal and frequency and/or phase changes corresponding to movement of equipment components.
13. The control system of claim 1 wherein the controller circuitry is programmed to evaluate and characterize frequency and/or phase characteristics of a post-occlusion surge event and control the one or more fluid control devices based on the frequency and/or phase characteristics of the post-occlusion surge event.
14. The control system of claim 1 wherein the controller circuitry is programmed to distinguish between a frequency domain representation of the time-domain signal resulting from an occlusion break event and a frequency domain representation of the time-domain signal resulting from a change in fluid flow due to sleeve resistance, wherein a change in a frequency content of the frequency domain representation of the time-domain signal is more significant during the occlusion break event than during the change in fluid flow due to sleeve resistance.
15. The control system of claim 1 wherein the controller circuitry is programmed to monitor a frequency domain representation of the time-domain signal of flow resistance in the system and to detect a change in the flow resistance in the system by detecting a change in the frequency and/or phase response of the system caused by a change in compliance of a fluid line.