A Compact Ionic Polymer-Metal Composite (IPMC) Actuated Valveless Pump for Drug Delivery

Abstract

This paper proposes a double-chamber valveless pump actuated by a cantilever ionic polymer-metal composite (IPMC), whose deflection is measured by inductive sensors. While IPMCs are regarded as a promising actuator for portable devices, their unique electrochemical and mechanical properties such as dehydration, hysteresis, and back-relaxation constraint are from real-life applications. To address these drawbacks, two adaptive control schemes, PID with iterative feedback tuning and repetitive control, were implemented and evaluated to compare tracking performance. The following contributions are presented based on the proposed IPMC pump: validation a double-chamber configuration addresses the back-relaxation problem of IPMC and compensates the nonlinearity of inductive sensors, demonstration of a compact configuration utilizing a contactless inductive sensor, controlling IPMC for over 2 h using repetitive control that favors tracking of periodic signal in terms of control effort, tracking error, and computational memory consumption. The pump has a maximum flow rate of 780 μL/min when the IPMC operates at a maximum deflection of 1.7 mm, which validates its suitability for use in drug delivery applications.