Flapping Wing Micro Air Vehicle Bench Test Setup

The purpose of this research was to develop testing methods that can be used to determine the forces, moments, and deflections involved in flapping wing aerodynamics. To pursue the research, a flapping wing mechanism and wings with spans ranging from 9.1 inches to 12.1 inches were built. A variety of mechanisms, capable of, alternatively, purely flapping, flapping with pitch, and flapping with pitch and out-of-plane motion were conceptualized and drawn using solid modeling software. Two of the simpler designs, a single degree-of-freedom flapping mechanism and the two-degree of freedom flapping mechanism were fabricated using a rapid prototype 3-D printer, and sustained operation was demonstrated. A thrust stand and a six-component force balance were used to gather force data from the flapping-only mechanism, combined with a variety of wing shapes. Four high-speed cameras were used to capture the motion of the wings. To minimize intrusiveness an array of laser dots was projected onto the wing during flapping and photogrammetry software was used to analyze the images and determine a shape profile of the wing composed of a frame and membrane during flapping. While the focus of this research was on the bench test setup development, some insight into the influence of wing design on the forces acting on the mechanism was gained

MEDIUM VOLTAGE DC SOLID STATE CIRCUIT BREAKER BENCH TEST

Next generation fleets will rely on medium-voltage direct-current (MVDC) electric power distribution systems utilizing high power density and high-efficiency components. One key gap to make such MVDC systems feasible is a super-fast, high-efficiency, and high power density protection device. The U.S. Navy has previously developed a 1 kV, 1 kA solid state circuit breaker (SSCB). A new 2 kV, 1.2 kA SSCB has been designed by NPS with collaborating partners that has quadrupled power density. This innovative insulated gate bipolar transistor (IGBT)-based SSCB consists of anti-series IGBT modules, a parallel resistor-capacitor (RC) branch, and an electronically triggered metal-oxide varistor (MOV) branch. The novel electronically controlled MOV is comprised of a MOV in series with a silicon controlled rectifier (SCR) passively triggered during the IGBT turn-off process, improving the trade-off between the leakage current and clamping voltage. The use of a lower IGBT gate voltage allows the elimination of current limiting inductors, increasing the SSCB power density. This thesis focuses on the switching and thermal tests necessary to validate the implemented concepts, and the data will be used for down-selecting technical directions, improving the SSCB performance. The results show that the SSCB is sufficient to interrupt most faults while containing peak current and voltage within design parameters and the efficiency target can be met with comfortable thermal margins.Lieutenant, United States NavyApproved for public release. Distribution is unlimited

In-Line-Test of Variability and Bit-Error-Rate of HfOx-Based Resistive Memory

Spatial and temporal variability of HfOx-based resistive random access memory (RRAM) are investigated for manufacturing and product designs. Manufacturing variability is characterized at different levels including lots, wafers, and chips. Bit-error-rate (BER) is proposed as a holistic parameter for the write cycle resistance statistics. Using the electrical in-line-test cycle data, a method is developed to derive BERs as functions of the design margin, to provide guidance for technology evaluation and product design. The proposed BER calculation can also be used in the off-line bench test and build-in-self-test (BIST) for adaptive error correction and for the other types of random access memories.Comment: 4 pages. Memory Workshop (IMW), 2015 IEEE Internationa

Sub-system mechanical design for an eLISA optical bench

We present the design and development status of the opto-mechanical sub-systems that will be used in an experimental demonstration of imaging systems for eLISA. An optical bench test bed design incorporates a Zerodur® baseplate with lenses, photodetectors, and other opto-mechanics that must be both adjustable - with an accuracy of a few micrometers - and stable over a 0 to 40°C temperature range. The alignment of a multi-lens imaging system and the characterisation of the system in multiple degrees of freedom is particularly challenging. We describe the mechanical design of the precision mechanisms, including thermally stable flexure-based optical mounts and complex multi-lens, multi-axis adjuster mechanisms, and update on the integration of the mechanisms on the optical bench

Control of unsteady separated flow associated with the dynamic stall of airfoils

The two principal objectives of this research were to achieve an improved understanding of the mechanisms involved in the onset and development of dynamic stall under compressible flow conditions, and to investigate the feasibility of employing adaptive airfoil geometry as an active flow control device in the dynamic stall engine. Presented here are the results of a quantitative (PDI) study of the compressibility effects on dynamic stall over the transiently pitching airfoil, as well as a discussion of a preliminary technique developed to measure the deformation produced by the adaptive geometry control device, and bench test results obtained using an airfoil equipped with the device

Experimental Assessment of Various Batteries and Propellers for Small Solar-Powered Unmanned Aerial Vehicle

In this study, the performance of the propulsion system of a solar-powered unmanned aerial vehicle (UAV) was investigated. Both battery and propeller variation tests were performed to evaluate their performance in relation to an electric motor. The battery was varied in the number of cells and capacity, and the propeller was varied in terms of diameter, pitch, manufacturer, and propeller type (fixed and folding propellers). For validation, the bench test result was compared with a simulation model. The bench test provided a reasonable guide for the throttle level required to obtain optimal power. A large variation existed in propeller performance between manufacturers. Sizing electric propulsion is important for UAV performance and the manufacturing factor is significant for propeller performance

Beam diagnostics for charge and position measurements in ELI-NP GBS

The advanced source of Gamma-ray photons to be built in Bucharest (Romania), as part of the ELI-NP European Research Infrastructure, will generate photons by Compton back-scattering in the collision between a multi-bunch electron beam and a high intensity recirculated laser pulse. An S-Band photoinjector and the following C-band Linac at a maximum energy of 720MeV, under construction by an European consortium (EurogammaS) led by INFN, will operate at 100Hz repetition rate with trains of 32 electron bunches, separated by 16ns and a 250pC nominal charge. The different BPMs and current transformers used to measure transverse beam position and charge along the LINAC are described. Design criteria, production status and bench test results of the charge and position pickups are reported in the paper, together with the related data acquisition systems

Nimbus B PCM telemetry subsystem, volume 1, sections 1 through 8 Final report,

Design, manufacture, and testing of Nimbus B PCM telemetry subsystem, bench test equipment, and ground station