ABSTRACT
This chapter discusses wireless control techniques for micromachined thermal actuators based on the radiofrequency (RF) excitation of passive wireless resonant heaters. It presents the application of the technique to an implantable drug-delivery device that uses thermoresponsive hydrogels as wirelessly controlled microvalves. Microelectromechanical systems for drug-delivery applications have attracted significant interest that has led to extensive investigations. The chapter describes the shape-memory-alloy (SMA) microgripper, in which the micromachined SMA structures are actuated using the developed RF technique. It also discusses the technique that enables multiple microactuator control and its demonstration with an SMA microsyringe. In the medical areas, SMA actuators offer attractive features such as very large actuation forces, high mechanical robustness with simple structures, and biocompatibility. A variety of thermal actuators may be operated in a wireless manner through this type of remote heating mechanism. The chapter focuses on research progress in wireless microactuators and their applications.
