Design and Verification of a Linear Parameter Varying Control Law for a Transport Aircraft

This paper presents the design, implementation and simulator verification of inner loop control laws based on linear parameter varying controller design techniques for a CS-25 certified fly-by-wire test aircraft. The synthesis method provides, in contrast to standard gain scheduling techniques, stability and robustness guarantees over the whole defined parameter envelope. Furthermore, it includes the design of the scheduling already in the synthesis process and avoids its a posteriori design. For the controller design, grid based linear parameter varying models of the longitudinal and lateral motion of the aircraft are generated. The longitudinal motion is augmented with two different reference tracking modes: load-factor and pitch rate command. The two control laws are compared in flight by the pilot to validate the handling qualities. The lateral motion control law features a rate command / attitude hold behavior, similar to schemes commonly used in fly-by-wire transport aircraft. Results from a simulation based verification campaign using DLR’s 6 degree of freedom Robotic Motion Simulator are presented as final results in this paper. The simulator verification was conducted as preparation for flight tests of the designed control laws on a Cessna Citation II (550) aircraft

Comparison of Multi-Fidelity Rotor Analysis Tools for Transitional and Low Speed Flight Regimes

Urban and regional air mobility is a new mode of transportation currently attracting a lot of attention. Much effort is being put into preliminary design studies for various electric vertical takeoff and landing (eVTOL) concepts. Especially the aerodynamic modeling poses major challenges to both applications, the preliminary design and the control design of eVTOLs. One main factor affecting aerodynamic complexity is rotor aerodynamics and the respective couplings with other rotors, wings, and airframe. Thus, both applications share the need for a fast and user-friendly, yet sufficiently accurate analysis tool. This study provides an overview of four different rotor aerodynamic tools suitable for the preliminary and control design task of eVTOLs and a respective tool-selection for different applications. A cross-method comparison is performed for the tools DUST, FLOWLab, SARF and OpenVSP/VSPAero, with a focus on capturing complex rotor, rotor-rotor and rotor-wing aerodynamics. The Caradonna-Tung rotor, for which experimental data is available, represents the benchmark case. Subsequently, the Airbus A3 Vahana is used to extend the analysis to an aerodynamically complex eVTOL configuration for which a main wing rotor is analyzed. There, the rotor aerodynamics is analyzed in different flight phases, i.e., different phases of the transition. The comparison of the two cases shows possibilities and limitations with respect to the quality of the computational results and handling aspects of the respective tools. The results suggest that DUST provides accurate results and covers most relevant effects at the cost of higher computational complexity. Both, the FLOWLab tools as well as SARF provide sufficiently accurate results in a short time. Though, SARF does not cover friction drag and thus underestimates the rotor torque. OpenVSP often shows convergence issues, but otherwise shows comparable results to the previous two tools

Emerging pharmacotherapy of tinnitus

Tinnitus, the perception of sound in the absence of an auditory stimulus, is perceived by about 1 in 10 adults, and for at least 1 in 100, tinnitus severely affects their quality of life. Because tinnitus is frequently associated with irritability, agitation, stress, insomnia, anxiety and depression, the social and economic burdens of tinnitus can be enormous. No curative treatments are available. However, tinnitus symptoms can be alleviated to some extent. The most widespread management therapies consist of auditory stimulation and cognitive behavioral treatment, aiming at improving habituation and coping strategies. Available clinical trials vary in methodological rigor and have been performed for a considerable number of different drugs. None of the investigated drugs have demonstrated providing replicable long-term reduction of tinnitus impact in the majority of patients in excess of placebo effects. Accordingly, there are no FDA or European Medicines Agency approved drugs for the treatment of tinnitus. However, in spite of the lack of evidence, a large variety of different compounds are prescribed off-label. Therefore, more effective pharmacotherapies for this huge and still growing market are desperately needed and even a drug that produces only a small but significant effect would have an enormous therapeutic impact. This review describes current and emerging pharmacotherapies with current difficulties and limitations. In addition, it provides an estimate of the tinnitus market. Finally, it describes recent advances in the tinnitus field which may help overcome obstacles faced in the pharmacological treatment of tinnitus. These include incomplete knowledge of tinnitus pathophysiology, lack of well-established animal models, heterogeneity of different forms of tinnitus, difficulties in tinnitus assessment and outcome measurement and variability in clinical trial methodology. © 2009 Informa UK Ltd.Fil: Langguth, Berthold. Universitat Regensburg; AlemaniaFil: Salvi, Richard. State University of New York; Estados UnidosFil: Elgoyhen, Ana Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

Follow-up observations at 16 and 33 GHz of extragalactic sources from WMAP 3-year data: I - Spectral properties

We present follow-up observations of 97 point sources from the Wilkinson Microwave Anisotropy Probe (WMAP) 3-year data, contained within the New Extragalactic WMAP Point Source (NEWPS) catalogue between declinations of -4 and +60 degrees; the sources form a flux-density-limited sample complete to 1.1 Jy (approximately 5 sigma) at 33 GHz. Our observations were made at 16 GHz using the Arcminute Microkelvin Imager (AMI) and at 33 GHz with the Very Small Array (VSA). 94 of the sources have reliable, simultaneous -- typically a few minutes apart -- observations with both telescopes. The spectra between 13.9 and 33.75 GHz are very different from those of bright sources at low frequency: 44 per cent have rising spectra (alpha < 0.0), where flux density is proportional to frequency^-alpha, and 93 per cent have spectra with alpha < 0.5; the median spectral index is 0.04. For the brighter sources, the agreement between VSA and WMAP 33-GHz flux densities averaged over sources is very good. However, for the fainter sources, the VSA tends to measure lower values for the flux densities than WMAP. We suggest that the main cause of this effect is Eddington bias arising from variability.Comment: 12 pages, 13 figures, submitted to MNRA

Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

An integrated data generation process for flight dynamics modeling in aircraft design

Flight mechanics analysis, loads analysis and control law synthesis share a common requirement – the availability of rigid and flexible flight dynamics models. These models usually derive input datasets from a multitude of engineering domains. In order to utilize these models early-on in the design process – specifically for the development of controlled simulation models at a preliminary design stage, methods have to be developed that allow sufficiently accurate input data decks from limited base information. In order to be capable of multi-configuration analysis, a sufficient degree of automation for each of the methods as well as for the overall generation process has to be achieved. This paper presents concepts and methods for this task – together with a specific insight regarding a derived method for the utilization of a Matlab/Catia link via the MS Windows COM interface together with respective applications

Open Innovation/Sagitta – Implementation and Validation of a Real-Time Flight Dynamics model for Simulation, Integration Testing and Pilot Training

The OpenInnovation/Sagitta project has its focus on the contribution of innovative technologies for the application within the UAV sector. Therein a number of research facilities and academic institutions – under the lead management of Airbus Defence and Space – are working together in order to resolve relevant questions: The Technical University of Munich (TUM), the University of the Armed Forces Munich (UniBW), the Technische Hochschule Ingolstadt (THI) and the TU Chemnitz (TUC), as well as the German Aerospace Center (DLR, being involved with a total of three institutes). Within project scope, a scaled demonstrator UAV aircraft has been designed for in-flight verification capabilities of the derived scientific project results. Aside the overall integration tasks in advance of its maiden flight, the aircraft is currently undergoing intensive simulation and integration testing activities on various levels. Within this paper, an overview of the general setup for these activities is given - specifically focusing on the required flight dynamics model (FDM) which depict the actual physical properties of the aircraft. Furthermore the respective implementation challenges due to project requirements are discussed in detail. Finally the performed validation tasks are described - as required to achieve clearance of the FDM for formal testing

Open Innovation / Sagitta Demonstrator UAV - Utilizing a flexible Real-Time Simulation and Integration Testing environment for Flight Operator and Pilot Training

The Open Innovation Sagitta project has its focus on the contribution of innovative technologies for the application within the UAV sector. Therein a number of research facilities and academic institutions – under the lead management of Airbus Defence and Space – have been working together in order to resolve relevant scientific questions regarding platform design methods, flight- and mission-management systems, as well as structural design and propulsion related topics. Within the project scope, a scaled demonstrator UAV has been designed and built for in-flight verification of scientific project results. Along with the overall system integration and testing tasks for first flight clearance, an additional focus has been given onto the operational work-flow development, training and emergency procedures for the flight operator and external pilots, as well as for the involved system engineers during flight test operations. This task has been achieved by using the dedicated Simulation and Integration Testing environment (SIT) in combination with the demonstrator aircraft and radio links as test rig, together with some functional extensions. This paper describes the general setup of the SIT environment, the respective data exchange infrastructure, as well as the utilized Simulation models and finally an exemplary training setup as applied during the Sagitta first flight campaign

Open Innovation/Sagitta – Implementation and Validation of a Real-Time Flight Dynamics model for Simulation, Integration Testing and Pilot Training

The OpenInnovation/Sagitta project has its focus on the contribution of innovative technologies for the application within the UAV sector. Therein a number of research facilities and academic institutions – under the lead management of Airbus Defence and Space – are working together in order to resolve relevant questions: The Technical University of Munich (TUM), the University of the Armed Forces Munich (UniBW), the Technische Hochschule Ingolstadt (THI) and the TU Chemnitz (TUC), as well as the German Aerospace Center (DLR, being involved with a total of three institutes). Within project scope, a scaled demonstrator UAV aircraft has been designed for in-flight verification capabilities of the derived scientific project results. Aside the overall integration tasks in advance of its maiden flight, the aircraft is currently undergoing intensive simulation and integration testing activities on various levels. Within this paper, an overview of the general setup for these activities is given - specifically focusing on the required flight dynamics model (FDM) which depict the actual physical properties of the aircraft. Furthermore the respective implementation challenges due to project requirements are discussed in detail. Finally the performed validation tasks are described - as required to achieve clearance of the FDM for formal testing