Analyse und Optimierung von fokussierten LiDAR-Systemen für Windkraftanlagen

Diese Dissertation beschäftigt sich mit der Auslegung fokussierter LiDAR-Sensorsysteme zur dopplerbasierten Messung der Windgeschwindigkeit für den prädiktiven Einsatz auf Windkraftanlagen. Für die Systemauslegung werden Geometrien des optischen Aufbaus mit Parametern der Windkraftanlage verknüpft, um eine Beurteilungsform für die Fähigkeit einer prädiktiven Steuerung zu entwickeln. Modellierungen und Messungen zeigen erhebliche Unterschiede zu den Annahmen des Standes der Technik

Receding horizon control (RHC) on a Lidar based preview controller design for the active wind turbine pitch system

In this paper, we present a design of a 2DOF (Degree Of Freedom) RHC/FB (FeedBack) control method for the pitch system of wind turbines based on the preview wind speed measurement by a Lidar system

Near Field iToF LIDAR Depth Improvement from Limited Number of Shots

Indirect Time of Flight LiDARs can indirectly calculate the scene's depth from the phase shift angle between transmitted and received laser signals with amplitudes modulated at a predefined frequency. Unfortunately, this method generates ambiguity in calculated depth when the phase shift angle value exceeds $2\pi$. Current state-of-the-art methods use raw samples generated using two distinct modulation frequencies to overcome this ambiguity problem. However, this comes at the cost of increasing laser components' stress and raising their temperature, which reduces their lifetime and increases power consumption. In our work, we study two different methods to recover the entire depth range of the LiDAR using fewer raw data sample shots from a single modulation frequency with the support of sensor's gray scale output to reduce the laser components' stress and power consumption

Lowering the Barrier for Successful Replication and Evaluation

Evaluation of a visualization technique is complex and time-consuming. We present a system that aims at easing design, creation and execution of controlled experiments for visualizations in the web. We include of parameterizable visualization generation services, thus separating the visualization implementation from study design and execution. This enables experimenters to design and run multiple experiments on the same visualization service in parallel, replicate experiments, and compare different visualization services quickly. The system supports the range from simple questionnaires to visualization-specific interaction techniques as well as automated task generation based on dynamic sampling of parameter spaces. We feature two examples to demonstrate our service-based approach. One example demonstrates how a suite of successive experiments can be conducted, while the other example includes an extended replication study

Nanotwinned silver nanowires: Structure and mechanical properties

Ag nanowires have been manufactured with the ultrathin layer electrochemical deposition method. Transmission electron microscopy revealed a multiple twinned nanostructure that has not been reported in comparable structures using a non-template self-assembling preparation method. The {1 1 1} twin planes are oriented parallel to the wire axis. The influence of the twin boundaries on the elastic and plastic properties of these wires has been investigated. Atomistic calculations revealed no influence of the twin boundaries on the Young's modulus of the wire for this geometry and along the direction. However, the twin boundaries exhibited a strong orientation-dependent influence on the plastic deformation when indented orthogonal ( direction) or parallel ( direction) to the twin boundaries, reflecting the interaction between the glide systems active in fcc metals and the stress direction. Heating experiments showed a high heat resistance for the twin boundaries till sublimation in an in situ TEM heating experiment. Sublimation followed the twin boundaries, indicating the lower binding energy of hcp stacking in comparison to fcc stacking. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved