US 12,263,122 B2
Methods of solenoid valve control optimization
Daryush Agahi, Irvine, CA (US); and Jiansheng Zhou, Cerritos, CA (US)
Assigned to Alcon Inc., Fribourg (CH)
Filed by Alcon Inc., Fribourg (CH)
Filed on Mar. 9, 2023, as Appl. No. 18/181,267.
Application 18/181,267 is a continuation of application No. 16/661,157, filed on Oct. 23, 2019, granted, now 11,642,243.
Claims priority of provisional application 62/777,406, filed on Dec. 10, 2018.
Prior Publication US 2023/0201033 A1, Jun. 29, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. F16K 31/06 (2006.01); A61F 9/007 (2006.01); F16K 37/00 (2006.01); G05D 7/06 (2006.01); H01F 7/06 (2006.01); H01F 7/16 (2006.01); A61B 17/00 (2006.01)
CPC A61F 9/00763 (2013.01) [F16K 31/0603 (2013.01); F16K 37/0041 (2013.01); G05D 7/0623 (2013.01); G05D 7/0635 (2013.01); H01F 7/064 (2013.01); H01F 7/16 (2013.01); A61B 2017/0019 (2013.01); A61B 2017/00544 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method of optimizing control of a solenoid valve for operating a vitrectomy probe comprising:
coupling a valve with a pressurized gas source, a power supply for supplying a voltage to drive a current in a solenoid in the valve, and a vitrectomy probe with a first chamber and a second chamber on respective sides of a pneumatically driven diaphragm for reciprocating a probe cutter;
delivering, by the power supply, the voltage to supply the solenoid with the current which drives a solenoid plunger to alternatively deliver and vent pressurized gas through a first outlet line and a second outlet line which respectively deliver and vent the pressurized gas to and from the first chamber and to and from the second chamber of the vitrectomy probe;
monitoring, with a current sensor coupled to the solenoid, the current in the solenoid;
transmitting, by the current sensor to a system controller, a current signal;
receiving, by the system controller, the current signal from the current sensor;
identifying, by the system controller, when a plunger movement in the solenoid creates a back electromotive force (back EMF) that changes the current in the solenoid in a predetermined degree, wherein identifying when the plunger movement in the solenoid creates the back EMF further comprises the system controller:
observing that the current is higher in each of a series of samples at a sampling rate;
observing that a subsequent series of subsequent samples in a sampling band are successively lower and resulted in a total current drop greater than a predetermined threshold indicating a peak;
observing that another series of subsequent samples are successively higher indicating a rebound in the current after the current rebounded from a valley; and
identifying a movement of the solenoid plunger created back EMF by observing the peak and valley;
causing, by the system controller, the power supply to enter a pulse width modulation (PWM) mode of operation to cause a continued movement of the solenoid plunger and/or hold an end position of the solenoid plunger until power to the solenoid is turned off at a predetermined timing after detecting the back EMF;
collecting current data associated with the detected peaks and valleys of the current signal;
predicting, via a failure prediction model, a future valve failure, wherein the failure prediction model is trained based on quantified instances of valve failure determined from the collected current data; and
displaying, on a surgical console coupled to the vitrectomy probe, advice for service of the valve based on the predicted future valve failure.