Entity

Time filter

Source Type

Garching bei Munchen, Germany

Liu G.,Northwestern Polytechnical University | Guo C.,Northwestern Polytechnical University | Zheng P.,Institute of Flight Mechanics and Flight Control
2010 IEEE Asia-Pacific Conference on Applied Electromagnetics, APACE 2010 - Proceedings | Year: 2010

A CPW-fed compact printed monopole antenna is proposed for portable UWB devices. The semi-ellipse and rectangle structure are combined as the radiator to expand the bandwidths of antenna to 2.3∼20.1 GHz (VSWR<2), except for the sub-band of 3.1∼4.4 GHz for WiMAX (3.3∼3.7 GHz) and the C-band satellite communication systems (3.7∼4.2 GHz). The notched sub-band is obtained by etching a C-shaped (circular arc) slot on the radiating patch. The measured results are in good agreement with the simulated ones. © 2010 IEEE. Source


Sachs G.,Institute of Flight Mechanics and Flight Control | Moelyadi M.A.,Bandung Institute of Technology
Journal of Bionic Engineering | Year: 2010

Using a sophisticated aerodynamic method, the effects of extremely large dihedral on the aerodynamic characteristics of birds are determined. With this method, it is possible to generate solutions for the addressed aerodynamic problem, which shows a high complexity due to interference effects caused by dihedral and pronounced 3-dimensional flow properties as well as due to complex wing geometries. From the obtained results it follows that extremely large dihedral has substantial effects on the aerodynamic force characteristics. There are significant changes in the lift, the drag and the side force, thus affecting the flight performance. Furthermore, the obtained results show that the aerodynamic rolling and yawing moment characteristics are influenced by extremely large dihedral to a high degree. This is a significant outcome for lateral-directional stability because the aerodynamic rolling and yawing moment characteristics have a determinative influence here. © 2010 Jilin University. Source


Liu G.,Northwestern Polytechnical University | Guo C.,Northwestern Polytechnical University | Zheng P.,Institute of Flight Mechanics and Flight Control | Ren A.,Northwestern Polytechnical University
2010 9th International Symposium on Antennas Propagation and EM Theory, ISAPE 2010 | Year: 2010

A CPW-fed compact printed monopole antenna is proposed for portable UWB devices. The semi-ellipse and rectangle structure are combined as the radiator to expand the bandwidths of antenna to 2.3∼20.1 GHz (VSWR<2), except for the two sub-bands of 3.1∼4.4 GHz for WiMAX (3.3∼3.7 GHz), the C-band satellite communication systems (3.7∼4.2 GHz), and 5.1∼5.9 GHz for WLAN. These notched sub-bands are obtained by etching two C-shaped (circular arc) slots on the radiating patch. The measured results are in good agreement with the simulated ones. ©2010 IEEE. Source


Zurn M.,Queensland University of Technology | Morton K.,Queensland University of Technology | Heckmann A.,University of Stuttgart | McFadyen A.,Queensland University of Technology | And 2 more authors.
IEEE Aerospace Conference Proceedings | Year: 2016

There is an increased interest in the use of Unmanned Aerial Vehicles for load transportation from environmental remote sensing to construction and parcel delivery. One of the main challenges is accurate control of the load position and trajectory. This paper presents an assessment of real flight trials for the control of an autonomous multi-rotor with a suspended slung load using only visual feedback to determine the load position. This method uses an onboard camera to take advantage of a common visual marker detection algorithm to robustly detect the load location. The load position is calculated using an onboard processor, and transmitted over a wireless network to a ground station integrating MATLAB/SIMULINK and Robotic Operating System (ROS) and a Model Predictive Controller (MPC) to control both the load and the UAV. To evaluate the system performance, the position of the load determined by the visual detection system in real flight is compared with data received by a motion tracking system. The multi-rotor position tracking performance is also analyzed by conducting flight trials using perfect load position data and data obtained only from the visual system. Results show very accurate estimation of the load position (∼5% Offset) using only the visual system and demonstrate that the need for an external motion tracking system is not needed for this task. © 2016 IEEE. Source


Grzymisch J.,University of Stuttgart | Grzymisch J.,Institute of Flight Mechanics and Flight Control | Fichter W.,University of Stuttgart | Fichter W.,Institute of Flight Mechanics and Flight Control
Journal of Guidance, Control, and Dynamics | Year: 2014

A study was conducted to present an alternative analytic expression for an optimal observability objective that could be used to maximize observability for any given initial trajectory. The proposed objective function was more versatile due to its simple form and could easily be included within a higher-level trajectory optimization scheme. This simple form also helped in the understanding of the conditions that maximize observability, further broadening this understanding. An analytical solution for optimal observability maneuvers was developed using the proposed observability objective. These closed-form solutions are developed in a generic manner, applicable to any maneuver type and any a priori unknown trajectory. It was also show how the proposed framework could be easily modified to provide closed-form solutions for a variety of different constraints on the maneuvers and on the trajectory. Source

Discover hidden collaborations