Modeling of a Piezoelectric MEMS Micropump Dedicated to Insulin Delivery and Experimental Validation Using Integrated Pressure Sensors: Application to Partial Occlusion Management

Figure 1

(a) Schematic cross section of the pump chip (not to scale). The mechanical stops (pink pads) present on both top and bottom wafers are also used as antistiction features. The buried oxide is represented by the thick green line under the device layer. The vent of the outer pressure sensor and the piezo actuator are not represented here. The top channel is covered by a glass cap. (b) Actuation profile applied on the piezoelectric bender. Positive part (“PUSH”) corresponds to an upward movement of the pumping membrane and therefore to insulin infusion in the patient; negative part (“PULL”) corresponds to a downward movement of the pumping membrane, leading to the filling of the chamber with insulin coming from the reservoir. (c) General electrical network modeling the different pump elements: the insulin reservoir (A), the particle filter (B), the inlet valve (C), the channel from the inlet valve to the pumping chamber (D), the pumping membrane (E), the actuation and the pumping membrane displacement (F), the inner sensor (G), the outlet valve (H), the outer sensor (I), the backpressure (J), and the retroaction of the pressure in the pumping chamber on the membrane displacement (K).

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