A ’Millipede’ scanner model - Energy consumption and performance

This short report (1) describes an energy model for the seek and read/write operations in a mass-balanced Y-scanner for parallel-probe storage by IBM [1] and (2) updates the settings of the MEMS model in DiskSim with recent published figures from this XY-scanner. To speedup system simulations, a straight forward second-order model is used without control loop. Read/write operation is modeled by quasi-static calculations. To approximate seek behavior, ’bang-bang’ control is assumed; the result is close to the actual behavior with control loop [2]. Unfortunately, no energy measurements were available to validate the model. Using the proposed energy model, we are able to study the energy consumption of a MEMS-based storage device for different application areas and file systems

Optimized comb drive finger shape for shock-resistant actuation

This work presents the analytical solution, realization and measurement of a comb drive with finger shapes optimized for shock-resistant actuation. The available force for actuating an external load determines how large shock forces can be compensated for. An analytical expression is presented for the finger shape that provides a constant large available force over the actuation range. The finger shape is asymmetric, resulting in a 20% smaller unit cell width compared to a symmetric shape. This finger shape provides 4 times more available force than the standard straight finger shape

Multimodal Aerial Locomotion:An Approach to Active Tool Handling

The research focus in aerial robotics is shifting from contactless inspection toward interaction and manipulation, with the number of potential applications rapidly increasing [1]. Eventually, aerial manipulators, i.e., unmanned aerial vehicles (UAVs) equipped with manipulators, will likely take on hazardous maintenance tasks now performed by humans. For this to happen, aerial manipulators must be able to perform all the different operations required in these maintenance routines

Energy Tank-Based Wrench/Impedance Control of a Fully-Actuated Hexarotor: A Geometric Port-Hamiltonian Approach

In this work, we show how the interactive behavior of an aerial robot can be modeled and controlled effectively and elegantly in the port-Hamiltonian framework. We present an observer-based wrench/impedance controller for a fully-actuated hexarotor. The analysis and control are performed in a geometrically consistent manner on the configuration manifold of the special Euclidean group SE (3) such that the UAV’s nonlinear geometric structure is exploited. The controller uses a wrench observer to estimate the interaction wrench without the use of a force/torque sensor. Moreover, the concept of energy tanks is used to guarantee the system’s overall contact stability to arbitrary passive environments. The reliability and robustness of the proposed approach is validated through simulation and experiment

Fully Actuated Multirotor UAVs: A Literature Review

In the last decade, the aerial robotics community has witnessed an increased interest in fully actuated multirotor unmanned aerial vehicles (UAVs) that have more capabilities than conventional underactuated multirotors. This article collects the different UAV designs having fully actuated aerodynamic wrench generation proposed in the literature to date. The work includes a systematic derivation of the control-allocation matrix for all of the concepts as well as a discussion of the different quantitative criteria used for optimizing UAV designs

Probe storage

This chapter gives an overview of probe-based data storage research over the last three decades, encompassing all aspects of a probe recording system. Following the division found in all mechanically addressed storage systems, the different subsystems (media, read/write heads, positioning, data channel, and file system) will be discussed. In the media subsection various recording media will be treated, such as polymer based, phase change, ferroelectric and magnetic. In the probe array subsection various generations of thermal probes will be discussed, as well as examples of alternative write probes using currents, electric or magnetic fields, and different principles for data detection. Special attention is paid to parallel readout of probe arrays. In the positioning section, examples will be shown of electric and magnetic scanners, either precision engineered or realized by micromachining technologies, or combinations thereof. In the systems subsection the data channel will be discussed, including the read/write electronics circuitry, data detection, and coding algorithms. Special attention is paid to the writing strategy and considerations for probe-based storage file systems

Neuralgic amyotrophy and hepatitis E virus infection

Objective: To determine whether there is an association between an acute preceding hepatitis E virus (HEV) infection and neuralgic amyotrophy (NA), and if so, whether patients with HEV-related NA differ from patients without an associated HEV infection. Methods: HEV testing was conducted in a retrospective cohort of 28 Cornish patients with NA (2011-2013) and a prospective cohort of 38 consecutive Dutch patients with NA (2004- 2007). Acute-phase serum samples were analyzed for the presence of anti-HEV immunoglobulin (Ig) M and IgG and HEV RNA (quantitative real-time PCR). Results: Five cases (10.6%) of acute hepatitis E infection were identified in a total group of 47 patients with NA of whom serum samples were available. In 4 patients, HEV RNA was detected in serum samples taken at presentation. All patients with HEV-associated NA had clinical and electrophysiologic evidence of bilateral brachial plexus involvement. Anti-HEV IgM positivity was not related to age, sex, disease severity, disease course, or outcome. Conclusions: Acute hepatitis E is found in 10%of patients with NA from the United Kingdom and the Netherlands. Further research is required to investigate the role of HEV in NA in other geographical locations and to determine pathophysiologic mechanisms