Low-Power Actuation Methods for Highly Nonlinear Solitary Wave Transducers Used to Assess Human Eyes

Abstract

The use of highly nonlinear solitary waves (HNSW) to inspect structural properties is a new methodology with great promise. One application of HNSW is to measure intraocular pressure (IOP). This is accomplished with HNSW transducers designed using a chain of particles stacked in Hertzian contact. In consideration of the anatomy of the human eye, the particles and transducer are scaled down in size compared to those used in previous designs. With the end goal of a designing a small, mobile transducer, all electronic components need to be compact, and battery powered. The transducer design also needs to trigger and measure the HNSWs. To accomplish this, a particle chain containing ferromagnetic particles surrounded by an applied magnetic field is utilized. To start the wave, a striker particle is lifted and dropped by a solenoid. Controlling the solenoid is the first step in ensuring consistent HNSW waves which requires a driver to control the mechanism. Once triggered, HNSW travel through the particles causing a distortion in the magnetic field that is measured by an inductor coil. This paper will present the design of a new compact HNSW transducer and an experimental evaluation of the solenoid drivers and their current consumption.