SmartLact8: A Bio-Inspired Robotic Breast Pump for Customized and Comfort Milk Expression

Abstract

According to the 2018 National Immunization Survey conducted by the Center for Disease Control and Prevention (CDC), 83.9% of the breastfeeding mothers in the United States have used a breast pump at least once. However, the majority of existing products use a vacuum-only mechanism to extract milk. This causes common breast injuries such as nipple soreness, breast-tissue damage, and lactation complications after pumping. The objective of this work was to develop a bio-inspired breast pump prototype, named as SmartLac8, that can mimic infant suckling patterns. The input vacuum pressure pattern and compression forces are inspired from term infants' natural oral suckling dynamics captured in prior clinical experiments. Open-loop input-output data are used to perform system identification for two different pumping stages that facilitates controller design for closed-loop stability and control. A physical breast pump prototype with soft pneumatic actuators and custom piezoelectric sensors was successfully developed, calibrated, and tested in dry lab experiments. Compression and vacuum pressure dynamics were successfully coordinated to mimic the infant's feeding mechanism. Experimental data on sucking frequency and pressure on the breast phantom were consistent with clinical findings.

Keywords: breast pump; oral-feeding mechanism; piezoelectric sensors; soft robotic.

Figure 2

(a) Blueprint for the breast pump design, and (b) soft robotic pad model in SolidWorks.

Figure 1

(a) Ultrasound imaging of a Term Normal Infant’s oral cavity during breastfeeding visualizes the structure of maxilla (upper hard palate), manidble (tongue and jaw), nipple, and milk flow; (b) Sensor placement during clinical study [30]; (c) Raw intra-oral pressure data for Infant #6.

Figure 3

(a) Exploded view for soft robotic pad master moulds, and (b) 3D printing moulds with the PRUSA printer.

Figure 4

Fabrication process of the soft robotic pad with pneumatic fingers: (a) Pre-formed base seal for the pad; (b) mould for the pneumatic air chambers; (c) extracted model from the master mould; (d) bonded base to the pneumatic fingers; and (e) completed air chambers and pneumatic channels.

Figure 5

Fabrication process of the custom-made piezoelectric sensors: (a) Sensor layout for fabrication, (b) piezo-resistive sensors sealed with clear tape; (c) seal sensor on the base mould; and (d) bonded sensors to the base of the soft robotic pad.

Figure 6

(a) Static characteristics using different weight loads, and (b) dynamic characteristic by applying pulse loads and testing the response delay of the sensor.

Figure 7

(a) Experimental setup includes a piezoelectric sensor pad on the breast with the same sensors for the soft robotic pad to capture pressure data on the breast; (b) flowchart for the constructed control system for the SmartLac8 breast pump.

Figure 8

Experimental results on the soft robotic pad actuation with images for (a) not actuated pneumatic fingers, and (b) fully actuated pneumatic fingers.

Figure 9

System identification for stage 1 pumping frequency and strength: (a) vacuum pressure system identification, and (b) compression pressure system identification.

Figure 10

System identification for stage 1 pumping frequency and strength: (a) vacuum pressure system identification, and (b) compression pressure system identification.

Figure 11

Tracking performance for the real-time PID control vacuum and compression pressures.