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Articles 1 - 11 of 11
Full-Text Articles in Engineering
Prediction-Based Adaptive Robust Control For A Class Of Uncertain Time-Delay Systems, Jayaprakash Suraj Nandiganahalli, Cheolhyeon Kwon, Inseok Hwang
Prediction-Based Adaptive Robust Control For A Class Of Uncertain Time-Delay Systems, Jayaprakash Suraj Nandiganahalli, Cheolhyeon Kwon, Inseok Hwang
School of Aeronautics and Astronautics Faculty Publications
This paper presents an integrated control design approach for a class of dynamical systems that satisfy a certain matching condition subject to known input time-delay, unknown parameters, and time-varying disturbances, simultaneously. A novel nonlinear predictor adaptive robust control (PARC) is proposed to track a desired state trajectory. The controller uses predictor-based model compensation to attenuate the effect of input time-delay, gradient type projection with prediction-based learning mechanisms to reduce the parameter uncertainties, and prediction-based nonlinear robust feedback to attenuate the effect of model approximation errors and disturbances, simultaneously. The controller guarantees a prescribed transient performance (with global exponential convergence) and …
Design Of Dc-Link Vscf Ac Electrical Power System For The Embraer 190/195 Aircraft, Eduardo Francis Carvalho Freitas, Nihad E. Daidzic
Design Of Dc-Link Vscf Ac Electrical Power System For The Embraer 190/195 Aircraft, Eduardo Francis Carvalho Freitas, Nihad E. Daidzic
Journal of Aviation Technology and Engineering
A proposed novel DC-Link VSCF AC-DC-AC electrical power system converter for Embraer 190/195 transport category airplane is presented. The proposed converter could replace the existing conventional system based on the CSCF IDGs. Several contemporary production airplanes already have VSCF as a major or backup source of electrical power. Problems existed with the older VSCF systems in the past; however, the switched power electronics and digital controllers have matured and can be now, in our opinion, safely integrated and replace existing constant-speed hydraulic transmissions powering CSCF AC generators. IGBT power transistors for medium-level power conversion and relatively fast efficient switching are …
Design And Validation Of Pressure Based Flow Rate Soft Sensor For Freeze-Drying, Pasita Pibulchinda, Tong Zhu, Vaibhav Kshirsagar, Alina A. Alexeenko
Design And Validation Of Pressure Based Flow Rate Soft Sensor For Freeze-Drying, Pasita Pibulchinda, Tong Zhu, Vaibhav Kshirsagar, Alina A. Alexeenko
The Summer Undergraduate Research Fellowship (SURF) Symposium
Lyophilization or freeze drying is a process of removing water by sublimation. It is commonly used to extend the shelf life of drugs in the pharmaceutical industry. Because the process is costly and time consuming, precise and efficient pressure, temperature control and drying time estimation are required. It is the goal of freeze-drying to run at maximum capacity while staying within the safe zone by carefully controlling the sublimation rate. Currently, real time estimation of sublimation rate is still challenging. The technique available called Tunable diode laser absorption spectroscopy (TDLAS) is invasive, and requires major modifications. The current study focuses …
Additive Manufacturing Of High Solids Loading Hybrid Rocket Fuel Grains, Stephen P. Johnson, Michael Baier, Ibrahim E. Gunduz, Steven F. Son
Additive Manufacturing Of High Solids Loading Hybrid Rocket Fuel Grains, Stephen P. Johnson, Michael Baier, Ibrahim E. Gunduz, Steven F. Son
The Summer Undergraduate Research Fellowship (SURF) Symposium
Hybrid rocket motors offer many of the benefits of both liquid and solid rocket systems. Like liquid engines, hybrid rocket motors are able to be throttled, can be stopped and restarted, and are safer than solid rocket motors since the fuel and oxidizer are in different physical states. Hybrid rocket motors are similar to solid motors in that they are relatively simple and have a high density-specific impulse. One of the major drawbacks of hybrid rocket motors is a slower burning rate than solid rocket motors. Complex port geometries provide greater burning surface area to compensate for lower burning rates …
Operation Of The T-100 Hall Effect Thruster, Glynn Smith, Omar Dary, Alexey Shashurin
Operation Of The T-100 Hall Effect Thruster, Glynn Smith, Omar Dary, Alexey Shashurin
The Summer Undergraduate Research Fellowship (SURF) Symposium
The introduction of Hall Effect Thrusters from the former Soviet Union to the United States generated considerable interest in using the propulsion system aboard Western spacecraft. The established programs evaluated the SPT-100, and TAL-55 Hall Effect Thrusters for efficiency, lifetime, and performance characteristics. The T-100 model garnered only minor interest during this time compared with the same generation counterparts, the SPT-100, and TAL-55. This gap in knowledge on the efficiency, and performance of the T-100 warrants investigation into the design, and operation of the thruster. Operational characteristics will be measured on a restored T-100 Hall Thruster, using argon as a …
Hazard Assessment Of Meteoroid Impact For The Design Of Lunar Habitats, Herta Paola Montoya, Shirley Dyke, Julio A. Ramirez, Antonio Bobet, H. Jay Melosh, Daniel Gomez
Hazard Assessment Of Meteoroid Impact For The Design Of Lunar Habitats, Herta Paola Montoya, Shirley Dyke, Julio A. Ramirez, Antonio Bobet, H. Jay Melosh, Daniel Gomez
The Summer Undergraduate Research Fellowship (SURF) Symposium
The design of self-sustaining lunar habitats is a challenge primarily due to the Moon’s lack of atmospheric protection and hazardous environment. To assure safe habitats that will lead to further lunar and space exploration, it is necessary to assess the different hazards faced on the Moon such as meteoroid impacts, extreme temperatures, and radiation. In particular, meteoroids pose a risk to lunar structures due to their high frequency of occurrence and hypervelocity impact. Continuous meteoroid impacts can harm structural elements and vital equipment compromising the well-being of lunar inhabitants. This study is focused on the hazard conceptualization and quantification of …
Using P-Band Signals Of Opportunity Radio Waves For Root Zone Soil Moisture Remote Sensing, Phillip H. Lipinski, Benjamin R. Nold, James L. Garrison
Using P-Band Signals Of Opportunity Radio Waves For Root Zone Soil Moisture Remote Sensing, Phillip H. Lipinski, Benjamin R. Nold, James L. Garrison
The Summer Undergraduate Research Fellowship (SURF) Symposium
Retrieval of Root Zone Soil Moisture (RZSM) is important for understanding the carbon cycle for use in climate change research as well as meteorology, hydrology, and precision agriculture studies. A current method of remote sensing, GNSS-R uses GPS signals to measure soil moisture content and vegetation biomass, but it is limited to 3-5 cm of soil penetration depth. Signals of Opportunity (SoOp) has emerged as an extension of GNSS-R remote sensing using communication signals. P-band communication signals (370 MHz) will be studied as an improved method of remote sensing of RZSM. P-band offers numerous advantages over GNSS-R, including stronger signal …
Using High Resolution Images To Investigate Fatigue Crack Initiation Of Alloys At The Microstructural Level, Michael P. Reinhold, Alberto Mello, Michael Sangid
Using High Resolution Images To Investigate Fatigue Crack Initiation Of Alloys At The Microstructural Level, Michael P. Reinhold, Alberto Mello, Michael Sangid
The Summer Undergraduate Research Fellowship (SURF) Symposium
Microstructural features within a material dictate the material’s mechanical behavior and lead to localized strains as the sample is deformed. In order to further understand structural failure, an improved understanding of how microstructural features influence failure is necessary. Fatigue is one common mode of failure for aerospace applications, and a better understanding of the conditions of crack initiation can provide information that ultimately may increase longevity of aerospace systems. This paper investigates the hypothesis that fatigue crack initiation for a cyclically loaded sample is correlated to areas of higher localized strain. The experiment was conducted using a Ti-6Al-4V sample subjected …
Hybrid Buoyant Aircraft: Future Stol Aircraft For Interconnectivity Of The Malaysian Islands, Anwar Ul Haque, Waqar Asrar, Ashraf Ali Omar, Erwin Sulaeman, Jaffar Syed Mohamed Ali
Hybrid Buoyant Aircraft: Future Stol Aircraft For Interconnectivity Of The Malaysian Islands, Anwar Ul Haque, Waqar Asrar, Ashraf Ali Omar, Erwin Sulaeman, Jaffar Syed Mohamed Ali
Journal of Aviation Technology and Engineering
Hybrid buoyant aircraft are new to the arena of air travel. They have the potential to boost the industry by leveraging new emerging lighter-than-air (LTA) and heavier-than-air (HTA) technologies. Hybrid buoyant aircraft are possible substitutes for jet and turbo-propeller aircraft currently utilized in aviation, and this manuscript is a country-specific (Malaysia) analysis to determine their potential market, assessing the tourism, business, agricultural, and airport transfer needs of such vehicles. A political, economic, social, and technological factors (PEST) analysis was also conducted to determine the impact of PEST parameters on the development of buoyant aircraft and to assess all existing problems …
Modeling And Computation Of The Maximum Braking Energy Speed For Transport Category Airplanes, Nihad E. Daidzic
Modeling And Computation Of The Maximum Braking Energy Speed For Transport Category Airplanes, Nihad E. Daidzic
Journal of Aviation Technology and Engineering
Transport-category or FAR/CS 25 certified airplanes may occasionally become braking energy capacity limited. Such limitation may exist when heavy airplanes are departing airports at high-density altitudes, on relatively long runways, and/or possibly with some tailwind component. A maximum braking energy VMBE speed exists which may limit the maximum allowable takeoff decision/action speed V1. The ever-existing possibility of high-speed rejected takeoff in such conditions may also limit the airplane gross weight for declared available distances. To gain deeper insights and acquire better understanding of the topic, a theoretical model of the maximum braking energy and the related VMBE speed for T-category …
Multi-Stage Nozzle-Shape Optimization For Pulsed Hydrogen-Air Detonation Combustor, Francesco Ornano, James Braun, Bayindir H. Saracoglu, Guillermo Paniagua
Multi-Stage Nozzle-Shape Optimization For Pulsed Hydrogen-Air Detonation Combustor, Francesco Ornano, James Braun, Bayindir H. Saracoglu, Guillermo Paniagua
School of Aeronautics and Astronautics Faculty Publications
hermal engines based on pressure gain combustion offer new opportunities to generate thrust with enhanced efficiency and relatively simple machinery. The sudden expansion of detonation products from a single-opening tube yields thrust, although this is suboptimal. In this article, we present the complete design optimization strategy for nozzles exposed to detonation pulses, combining unsteady Reynolds-averaged Navier-Stokes solvers with the accurate modeling of the combustion process. The parameterized shape of the nozzle is optimized using a differential evolution algorithm to maxi mize the force at the nozzle exhaust. The design of experiments begins with a first optimization considering steady-flow conditions, subsequently …