Magnetic polymer composites (MPC) have shown promise for emerging biomedical applications such as lab-on-a-chip and implantable drug delivery. These soft material actuators are capable of fast response, large deformation and wireless actuation. Existing MPC modeling approaches are computationally expensive and unsuitable for rapid design prototyping and real-time control applications. This paper proposes a macro-scale 1-DOF model capable of predicting force and displacement of an MPC diaphragm actuator. Model validation confirmed both blocked force and displacement can be accurately predicted in a variety of working conditions i.e. different magnetic field strengths, static/dynamic fields, and gap distances. The contribution of this work includes a comprehensive experimental investigation of a macro-scale diaphragm actuator; the derivation and validation of a new phenomenological model to describe MPC actuation; and insights into the proposed model’s design-based functionality i.e. scalability and generalizability in terms of magnetic filler concentration and diaphragm diameter. Due to the lumped element modeling approach, the proposed model can also be adapted to alternative actuator configurations, and thus presents a useful tool for design, control and simulation of novel MPC applications.

This paper reports a novel, wireless magnetic polymer material actuator for implantable devices. Unlike existing magnetically-driven actuators, the proposed configuration requires only a single electromagnet for actuation. The performance of this material actuator is evaluated within. In addition, the effects of changing material composition were also investigated. Results show the actuator is capable of wireless actuation from a distance of 6 mm, with a maximum displacement of 5 mm when exposed to a magnetic field (0.23 Tesla). The material actuator can also operate at relatively high frequencies, up to 29 Hz, compared with existing soft materials. Two actuators of different magnetic filler concentration, 10wt% and 20wt%, were tested. Increasing the magnetic filler concentration increased displacement but also resulted in increased material stiffness. The proposed magnetic polymer actuator demonstrated large displacement, high-frequency operation and most importantly, wireless actuation. Actuation did not require a physical electrical connection or onboard electronics, showing promise for inherently safe wireless implantable devices.

Magnetic polymer composites (MPCs) are soft material actuators capable of large deformation and fast response. They are wirelessly actuated and do not require onboard electronics or a power supply. Despite MPCs potential, the accuracy and reliability of controlling material displacement is unknown. This paper investigates the performance of three controllers for MPC position tracking: open-loop, fixed gain proportional-integral-derivative (PID) and gain scheduled PID. A systematic workflow, from plant identification to controller gain tuning, is presented, as well as a comprehensive experimental analysis of each controller. Due to observed nonlinear behavior, open-loop and fixed gain PID control were inadequate for fast, accurate position tracking. Gain scheduled PID presented a viable and efficient option for closed-loop displacement control.