A5026033429- Adhesion, Friction, and Surface Interactions
- Advanced MEMS and NEMS Technologies
- Force Microscopy Techniques and Applications
- Magnetic properties of thin films
- Mechanical and Optical Resonators
- Vibration and Dynamic Analysis
- Robotic Path Planning Algorithms
- Cellular Automata and Applications
- Ecology and Vegetation Dynamics Studies
- Phase-change materials and chalcogenides
- Acoustic Wave Resonator Technologies
- Semiconductor materials and devices
- Fluid Dynamics and Vibration Analysis
- Robotics and Sensor-Based Localization
- Advanced Data Storage Technologies
- Mechanical stress and fatigue analysis
- Adaptive Control of Nonlinear Systems
- Rangeland and Wildlife Management
- Rabbits: Nutrition, Reproduction, Health
- Guidance and Control Systems
- Soft Robotics and Applications
- Ferroelectric and Piezoelectric Materials
- Ferroelectric and Negative Capacitance Devices
- Control and Dynamics of Mobile Robots
- Near-Field Optical Microscopy
University of Twente
2008-2020
IBM Research - Zurich
2013-2017
IBM (United States)
2012-2015
In this work, we show how the interactive behavior of an aerial robot can be modeled and controlled effectively elegantly in port-Hamiltonian framework. We present observer-based wrench/impedance controller for a fully-actuated hexarotor. The analysis control are performed geometrically consistent manner on configuration manifold special Euclidean group SE (3) such that UAV's nonlinear geometric structure is exploited. uses wrench observer to estimate interaction without use force/torque...
1 The sources of propagules for regeneration in an acidic grassland were identified from analysis differences colonization between plots subject to surface (0–5 cm) soil disturbance and where had been replaced by ‘seed‐free’ deeper horizons (30–35 cm), with without the removal rabbit pellets. 2 After year, 10 species a significantly higher cover on seed bank left intact. These included Agrostis capillaris (the dominant prior disturbance), Myosotis arvensis Veronica . 3 Five species,...
The recording performance of a prototype magnetic tape based on perpendicularly oriented barium ferrite particles is investigated using an enhanced field write head and 90 nm wide giant-magnetoresistive reader. A linear density 680 kbits/in with postdetection byte-error rate (BER) <;3.2e-2 demonstrated recorded data processed by software read channel noise-predictive maximum likelihood detection. With this detector error rate, user BER <;1e-20 can be achieved means product correction coding...
Magnetic dot arrays with perpendicular magnetic anisotropy were fabricated by patterning Co(80)Pt(20)-alloy continuous films means of laser interference lithography. As commonly seen in large arrays, there is a difference the switching field between dots. Here we investigate origin this distribution, using anomalous Hall effect (AHE). The high sensitivity AHE permits us to measure reversal individual dots an array 80 diameter 180 nm. By taking 1000 hysteresis loops reveal thermally induced...
This work presents a MEMS displacement sensor based on the conductive heat transfer of resistively heated silicon structure towards an actuated stage parallel to structure. differential can be easily incorporated into silicon-on-insulator-based process, and fabricated within same mask as electrostatic actuators flexure-based stages. We discuss lumped capacitance model optimize sensitivity function doping concentration, operating temperature, heater length width. demonstrate various designs....
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, manipulators, i.e., unmanned vehicles (UAVs) equipped will likely take on hazardous maintenance tasks now performed by humans. For this to happen, manipulators must be able perform all different operations required these routines.
The recording performance of a new magnetic tape based on perpendicularly oriented barium ferrite particles was investigated using 90-nm-wide giant-magnetoresistive reader and prototype enhanced-field write head. A linear density 600 kb/in with postdetection byte-error rate <;3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> demonstrated measured data software read channel that used noise-predictive maximum likelihood detection...
In this work we describe an electrostatic mass-balanced planar x/y-scanner, using optimized comb finger shape, designed for parallel-probe storage applications. We show a new stepped shape design, that has superior force/displacement characteristics leading to larger stroke at the same voltage and available force compared straight or tapered shapes.
In this paper, we study the mechanical interface between a hard-disk drive (HDD) head and magnetic recording tape to enable use of HDD heads investigate future operating points. Tape surface height measurements were obtained using an interferometer microscope for varying wrap angle configurations, velocities, tensions. Simultaneously, readback signal from read element was captured quality contact head. The signal-to-noise ratio (SNR) bit-error rate (BER) performance pseudorandom bit sequence...
This work presents the analytical solution, finite-element analysis, realization and measurement of comb drives with finger shapes optimized for shock-resistant actuation. The available force actuating an external load determines how large shock forces can be compensated for. shape provides much more than standard straight shape, especially at displacements. A graphical method is presented to determine whether stable voltage control possible a given curve. An expression that constant over...
In this work we present the optimization-based design and control of a fully-actuated omnidirectional hexarotor. The tilt angles propellers are designed by maximizing wrench applied propellers. This maximizes (a) agility UAV, (b) maximum payload UAV can hover with at any orientation, (c) interaction that apply to environment in physical contact. It is shown only axial tilting respect UAV's body yields optimal results. Unlike conventional hexarotor, proposed hexarotor generate least 1.9 times...
The Micronium is a musical instrument fabricated from silicon using microelectromechanical system (MEMS) technology. It is-to the best of our knowledge-the first micro-instrument MEMS technology, where actual sound generated by mechanical microstructures. consists mass-spring systems that are designed to resonate at audible frequencies. Their displacement measured comb drives and used as audio signal drive loudspeaker. instrument's sounds pure sine waves. An extensive set measurements...
The friction and magnetic spacing between tape a recording head are measured as function of the wrap angle at several speeds tensions for two samples with different roughnesses. An increase in decrease for: 1) increasing angle; 2) decreasing speed; 3) tension. relation is fixed when varying tension or angle. For rougher sample, reducing speed (and adjusting accordingly) reduces without friction. Although smoother experiences more tension, smaller specified it than tape.
We present a planar thin-film servo write head for writing timing-based patterns. The operates at low current ( <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">${\sim}100$</tex></formula> mA) with nanosecond switching times. can handle dc current, enabling trailing-edge writing. Magnetic force microscopy measurements of the transitions written by and conventional commercial on longitudinal metal...
This work presents the analytical solution, realization and measurement of a comb drive with finger shapes optimized for shock-resistant actuation. The available force actuating an external load determines how large shock forces can be compensated for. An expression is presented shape that provides constant over actuation range. asymmetric, resulting in 20% smaller unit cell width compared to symmetric shape. 4 times more than standard straight
A new way to characterize vibrating MEMS devices is presented. Using an acoustic particle velocity sensor the coupled sound field measured, which a measure for movement of device. We present several possible applications this measurement method. It can be used as read-out system mass flow sensor, and characterization in- out-of-plane movements devices. The method interesting alternative laser scanning vibrometry due its small size low complexity; furthermore, it allows user `listen' directly