Herbert Shea

Muhamed Niklaus4
Daniel G Courtney3
4Muhamed Niklaus
3Daniel G Courtney
3Vinu Venkatraman
Learn More
We report on the fabrication and characterization of 2x2 arrays of mm-diameter PDMS lenses whose focal length can be electrically tuned. Dielectric elastomer actuators generally rely on carbon powder or carbon grease electrodes, which are not transparent, precluding the polymer actuator from also being a lens. However compliant electrodes fabricated by(More)
—We report on the characterization, active tuning, and modeling of the first mode resonance frequency of dielectric electroactive polymer (DEAP) membranes. Unlike other resonance frequency tuning techniques, the tuning procedure presented here requires no external actuators or variable elements. Compliant electrodes were sputtered or implanted on both sides(More)
A highly versatile soft gripper that can handle an unprecedented range of object types is developed based on a new design of dielectric elastomer actuators employing an interdigitated electrode geometry, simultaneously maximizing both electroadhesion and electrostatic actuation while incorporating self-sensing. The multifunctionality of the actuator leads(More)
— A novel variable stiffness actuator composed of a dielectric elastomer actuator (DEA) and a low-melting-point-alloy (LMPA) embedded silicone substrate is demonstrated. The device which we call variable stiffness dielectric elastomer ac-tuator (VSDEA) enables functional soft robots with a simplified structure, where the DEA generates a bending actuation(More)
Nomenclature c k = speed of species k, m∕s f = fraction of solvated ions that fragment I = normalized collected current I b = total thruster beam current, A I sp = specific impulse, s K k = kinetic energy of species k, J L = time-of-flight distance _ m = calculated mass flow rate, kg∕s m k = mass of species k, kg q = ion electric charge, C T = calculated(More)
We present the microfabrication and characterization of a low-power, chip-scale Rb plasma light source, designed for optical pumping in miniature atomic clocks. A dielectric barrier discharge (DBD) configuration is used to ignite a Rb plasma in a micro-fabricated Rb vapor cell on which external indium electrodes were deposited. The device is electrically(More)
The application of electrical fields within a microfluidic channel enables many forms of manipulation necessary for lab-on-a-chip devices. Patterning electrodes inside the microfluidic channel generally requires multi-step optical lithography. Here, we utilize an ion-implantation process to pattern 3D electrodes within a fluidic channel made of(More)
Electric propulsion systems using electrospray ion sources are a scalable and high specific impulse technology which could enable small spacecraft to perform high ΔV missions. This paper presents an overview of a recently developed source design which achieves 10's of μN of thrust at less than 1 W of input power with a specific impulse up to ∼3000 s.(More)
The force (F) and the power consumption (P) of a magnetic actuator are modeled, measured and optimized in the context of developing micro-actuators for large arrays, such as in portable tactile displays for the visually impaired. We present a novel analytical approach complemented with finite element simulation (FEM) and experiment validation, showing that(More)