Occlusion detection for a fluid infusion device
View Patent ↗A device for delivering fluid to a user includes a housing, a drive motor assembly in the housing, a force sensor, and an electronics module. The drive motor assembly regulates delivery of fluid by actuating a piston of a fluid reservoir, and the force sensor generates output levels in response to force imparted thereto during, for example, fluid delivery operations. The electronics module processes the output levels of the force sensor to assess the operating health of the force sensor, to check for occlusions in the fluid delivery path, and to monitor the seating status of the fluid reservoir.
1. In a fluid infusion device comprising a drive motor assembly and a force sensor associated with the drive motor assembly, a method of detecting occlusions in a fluid path of the fluid infusion device, the method comprising:
determining a plurality of force measurements for a fluid delivery action of the drive motor assembly, the plurality of force measurements indicating measures of actuation force imparted to the force sensor for the fluid delivery action;
determining a plurality of quantity measurements for the fluid delivery action, each of the plurality of quantity measurements being determined relative to a reference quantity measurement;
indicating an occlusion when a first slope of force-versus-quantity for a large sample of the plurality of quantity measurements is greater than or equal to a first threshold slope value; and
indicating an occlusion when both: (a) a second slope of force-versus-quantity for a small sample of the plurality of quantity measurements is greater than or equal to a second threshold slope value; and (b) a current one of the plurality of force measurements is greater than or equal to a threshold force value,
wherein:
each of the plurality of quantity measurements indicates a volume of fluid dispensed from a fluid reservoir of the fluid infusion device;
the large sample corresponds to a predefined large volume reference; and
the small sample corresponds to a predefined small volume reference.
2. In a fluid infusion device comprising a drive motor assembly and a force sensor associated with the drive motor assembly, a method of detecting occlusions in a fluid path of the fluid infusion device, the method comprising:
determining a plurality of force measurements for a fluid delivery action of the drive motor assembly, the plurality of force measurements indicating measures of actuation force imparted to the force sensor for the fluid delivery action;
determining a plurality of quantity measurements for the fluid delivery action, each of the plurality of quantity measurements being determined relative to a reference quantity measurement;
calculating a first slope of force-versus-quantity based upon the current one of the plurality of force measurements, a current one of the plurality of quantity measurements, corresponding to the current one of the plurality of force measurements, a previous one of the plurality of force measurementsand a previous one of the plurality of quantity measurements, corresponding to the previous one of the plurality of force measurements;
indicating an occlusion when the first slope of force-versus-quantity for a large sample of the plurality of quantity measurements is greater than or equal to a first threshold slope value; and
indicating an occlusion when both: (a) a second slope of force-versus-quantity for a small sample of the plurality of quantity measurements is greater than or equal to a second threshold slope value; and (b) a current one of the plurality of force measurements is greater than or equal to a threshold force value.
3. The method of claim 2 , further comprising the step of calculating the second slope based upon:
the current one of the plurality of force measurements;
the current one of the plurality of quantity measurements;
an intervening one of the plurality of force measurements; and
an intervening one of the plurality of quantity measurements, corresponding to the intervening one of the plurality of force measurements, wherein the intervening one of the plurality of force measurements is determined after determining the previous one of the plurality of force measurements, and wherein the intervening one of the plurality of quantity measurements is determined after determining the previous one of the plurality of quantity measurements.