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Viewing 61 to 90 of 33398
2017-09-23
Technical Paper
2017-01-1958
Abstract With the increasing complexity, dynamicity and uncertainty of traffic, motion planning of automatic driving is getting more difficult and challenging. This paper focuses on the real-time motion planning problem of CAVs (connected and automated vehicles) in complex traffic scenarios. To effectively solve this problem, a general driving risk model is presented, which contains the following two essential parts: i) collision risk, i.e., the collision risk between the SV (subject vehicle) and other surrounding vehicles, pedestrians, buildings etc.; ii) non-collision risk, such as violation of traffic regulations, the deviation from the intention of driver, etc. To achieve the real time collision detection, the SV is approximated to a point and its shape is considered by extending the dimension of obstacles considering their relative position and velocity.
2017-09-23
Technical Paper
2017-01-1991
Adit Joshi
The automotive industry is heading towards the path of autonomy with the development of autonomous vehicles. An autonomous vehicle consists of two main components. The first is the software which is responsible for the decision-making capabilities of the system. The second is the hardware which encompasses all aspects of the physical vehicle which are responsible for vehicle motion such as the engine, brakes and steering subsystems along with their corresponding controls. This component forms the basis of the autonomous vehicle platform. For SAE Level 4 autonomous vehicles, where an automated driving system is responsible for all the dynamics driving tasks including the fallback driving performance in case of system faults, redundant mechanical systems and controls are required as part of the autonomous vehicle platform since the driver is completely out of the loop with respect to driving.
2017-09-23
Technical Paper
2017-01-1994
Adit Joshi
The advancement towards development of autonomy follows either the bottom-up approach of gradually improving and expanding existing Advanced Driver Assist Systems (ADAS) technology where the driver is present in the control loop or the top-down approach of directly developing Autonomous Vehicles (AV) hardware and software using alternative approaches without the driver present in the control loop. Most ADAS systems today fall under the classification of SAE Level 1 which is also referred to as the driver assistance level. The progression from SAE Level 1 to SAE Level 2 or partial automation involves the critical task of merging autonomous lateral control and autonomous longitudinal control such that the tasks of steering and acceleration/deceleration are not required to be handled by the driver under certain conditions [1].
2017-09-23
Technical Paper
2017-01-1996
Zhichao Lin, Xuexun Guo, Xiaofei Pei, Bo Yang, Yanggang Zhang
Abstract Dynamic modeling and state estimation are significant in the trajectory tracking and stability control of the intelligent vehicle. In order to meet the requirement of the stability control of the eight-in-wheel-motor-driven intelligent vehicle, a full vehicle dynamics model with 12 degrees of freedom, including the longitudinal, lateral, yaw and roll motion of the body, and rotational motion of 8 wheels, is established for the research of the intelligent vehicle in this paper. By simulation with MATLAB/SIMULINK and by comparison with the TruckSim software, the reliability and practicality of the dynamics model are verified. Based on the established dynamics model, an extended Kalman filter (EKF) state observer is proposed to estimate the vehicle sideslip angle, roll angle and yaw rate, which are the key parameters to the stability control of the intelligent vehicle.
2017-09-23
Technical Paper
2017-01-2000
Jianping Li, Jian Wu, Hao Sun, Yuyao Jiang, Weiwen Deng, Bing Zhu
Abstract Simulation has been considered as one of the key enablers on the development and testing for autonomous driving systems as in-vehicle and field testing can be very time-consuming, costly and often impossible due to safety concerns. Accurately modeling traffic, therefore, is critically important for autonomous driving simulation on threat assessment, trajectory planning, etc. Traditionally when modeling traffic, the motion of traffic vehicles is often considered to be deterministic and modeled based on its governing physics. However, the sensed or perceived motion of traffic vehicles can be full of errors or inaccuracy due to the inaccurate and/or incomplete sensing information. In addition, it is naturally true that any future trajectories are unknown. This paper proposes a novel modeling method on traffic considering its motion uncertainties, based on Gaussian process (GP).
2017-09-23
Technical Paper
2017-01-2004
Yangyang Wang, Rong Feng, Ding Pan, Zhiguang Liu, Nan Wu, Wei Li
Abstract The automatic lane change assist system is an intelligent driving assistance technology oriented to traffic safety, which requires trajectory planning of the lane change maneuver based on the lane change decision. A typical scene of lane change for overtaking is selected, where the front vehicle in the same lane and the rear vehicle in the left lane are deemed to be potential dangerous vehicles through the lane change. Lane change trajectory equation is first established according to the general law of steering wheel angle through lane changes. Based on the relative position, velocity and acceleration information of the dangerous vehicles and the lane change vehicle, motions of these surrounding dangerous vehicles are predicted. At the same time, a multi-objective optimization function is established based on the relative longitudinal safety boundary. The objectives are the minimum safety distance, the lane change time and the front wheel angle.
2017-09-19
Technical Paper
2017-01-2160
Ferdinand Spek, Maarten Weehuizen, Ilja Achterberg
In new aircraft programs, systems’ functionality is increasingly becoming integrated into modular avionics. Controllers may not be delivered by the systems supplier so this trend creates a new interface between systems and controllers. A functional software specification is therefore needed to facilitate the building of the software by the controller supplier. In the case of an ECS system controller, the hardware was obtained from different suppliers and a software functional specification was needed for the controller supplier. To be able to design and verify the system functionality, an integrated ECS simulation model was created which coupled the thermodynamics of the aircraft and ECS system to the controller actions. The model also included functionality to simulate sensor noise and component failures. The thermodynamic model was created in Matlab/Simulink and consisted of a combination of direct programming as well as data on a Flowmaster model for the bleed system.
2017-09-19
Technical Paper
2017-01-2110
Ashutosh Kumar Jha, Prakash Choudhary
The complexity of software development is increasing unprecedentedly with every next generation of aircraft systems. This requires to adopt new techniques of software design and verification that could optimize the time and cost of software development. At the same time these techniques need to ensure high quality of software design and safety compliance to regulatory guidelines like DO-178C[1] and its supplements DO-330[2] and DO-331[3]. To arrive at new technologies one has to evaluate the alternate methods available for software design by developing models, integration of models, auto-code generation, auto test generation and also the performance parameters like time, effort, reuse and presentability needs to be evaluated. We have made an attempt to present summary of alternate design concept study, and edge of MBD over other design techniques.
2017-09-19
Technical Paper
2017-01-2136
Almuddin Rustum Sayyad, Pratik Salunke, Sangram Jadhav
The objective of this work is to optimize the operating parameters of the Direct Injection single cylinder (5.2 kw) CI engine with respect to Brake Thermal Efficiency (BTHE), Hydro carbons (HC) and Carbon dioxide (CO2). For this investigation, we used Simarouba Biodiesel as an alternate fuel for diesel fuel which possesses low cetane number which is not sufficient to operate existing diesel engine. However, this could be combined with the diesel fuel in the form of blends. For this investigation four levels and four parameters were selected viz. Injection Pressure (IP), Fuel Fraction (FF), Compression Ratio (CR) and Injection Timing (Before TDC). Taguchi Method is used for minimizing the number of experiments and Multiple Regression Analysis is used to find the optimum condition. Three outputs variables such as; Brake Thermal Efficiency (BTHE), content of HC particles and CO2 in the emission are measured and considered its influence on CI Engine performance.
2017-09-19
Technical Paper
2017-01-2137
Dnyaneshwar V. Kadam, Sangram D. Jadhav
Vibration is the most considerable factor in dynamics of machinery. Vibration causes unfavorable effects on engine components and may reduce the life of engine. The conventional fossil fuel sources are limited in the world. The dependency on diesel should be reduced by using biodiesel as an alternative fuel in next few years. The input parameters are affected on engine performance and emission. The present study mainly focuses on an optimization of vibrations, performance and emission using Taguchi and multiple regression analysis for biodiesel as a fuel. The test was performed on single cylinder, four-stroke, diesel engine with VCR. Taguchi method is used to prepare the design of experiment of L16 array for minimizing number of experiments and multiple regression analysis for finding the best relationship between the input and output parameters. The selected input parameters are: fuel fraction, compression ratio, injection pressure and injection timing.
2017-09-19
Technical Paper
2017-01-2044
Mithilesh Kumar Sahu, Tushar Choudhary, Sanjay Y
Aircraft engines powering propulsion of the aircraft is the key component of the system. In aircraft industry it is desirable that an aircraft engines should supply high speeds (for military fighters) with low maintenance (for civil airplanes). In this regard an integration of gas turbine engines with traditional propeller has been introduced and termed as turboprop engine. In present work, a gas turbine with cooled blading has been proposed to be the turboprop engine which has been exergoeconomically analysed to assess the performance and economics related to the proposed turboprop engine. Exergoeconomic analysis is a tool which combines thermodynamic analysis and economic principles to provide information that is helpful to predict thermodynamic performance and total cost of the engine (thermal system). The methodology includes energy, exergy and cost balance equations for component-wise modelling of whole system.
2017-09-19
Technical Paper
2017-01-2046
Pejman Akbari, Ian Agoos
The Wave Disk Engine (WDE) is a novel engine that has the potential for higher efficiency and power density of power-generation systems. A recent version of wave disk engine architecture known as the two-stage WDE has been studied to address existing challenges of an existing WDE. After describing the engine operation, a cold air-standard thermodynamic model supporting the physical phenomena occurring inside the device is introduced to evaluate performance of the engine. The developed model is general and does not depend on the shape of the wave rotor, it can be applied to radial and axial combustion wave rotors integrated with turbomachinery devices. The analysis starts with predicting internal waves propagating inside the channels of the engine and linking various flow states to each other using thermodynamics relationships. The goal is to find analytical expressions of work output and efficiency in terms of known pressure and temperature ratios.
2017-09-19
Technical Paper
2017-01-2020
Michael Croegaert
Modern military aircraft platforms are using more and more power which results in an ever increasing power density (SWaP). This in turn, generates more heat that has to be dissipated from the instrument panel and cockpit of the aircraft. Complicating this further is that the use of structural composites which are not efficient conductors of heat and the mission requirements of small heat signatures. Therefore alternative means of extracting the heat from the avionics systems must be used. Liquid cooled systems have the advantage over air cooled systems of a much higher heat transfer rate and the fact that the heat can be transported a significant distance from the source. Liquid cooled avionics have their own challenges as well. The architecture of the components (cold plates, etc) used for extracting the heat from the electronics component must be optimized to perform consistently and reliably while maintaining the smallest footprint possible in the already crowded instrument panel.
2017-09-19
Technical Paper
2017-01-2034
Bailey Hall, Benjamin Palmer, Tyler Milburn, Luis Herrera, Bang Tsao, Joseph Weimer
Abstract Future aircraft will demand a significant amount of electrical power to drive primary flight control surfaces. The electrical system architecture needed to source these flight critical loads will have to be resilient, autonomous, and fast. Designing and ensuring that a power system architecture can meet the load requirements and provide power to the flight critical buses at all times is fundamental. In this paper, formal methods and linear temporal logic are used to develop a contactor control strategy to meet the given specifications. The resulting strategy is able to manage multiple contactors during different types of generator failures. In order to verify the feasibility of the control strategy, a real-time simulation platform is developed to simulate the electrical power system. The platform has the capability to test an external controller through Hardware in the Loop (HIL).
2017-09-19
Technical Paper
2017-01-2033
Minh-khoa. Lam, Christopher Buterhaugh, Luis Herrera, Bang Tsao
Abstract The amount of electrical power required for future aircraft is increasing significantly. In this paper, a comprehensive model of a drive shaft with multiple degrees of freedom was developed and integrated to detailed engine and electrical network models to study the impact of higher electrical loads. The overall system model is composed of the engine, shafts, gearbox, and the electric network. The Dynamic Dual Spool High Bypass JT9D engine was chosen for this study. The engine was modeled using NASA’s T-MATS (Toolbox for the Modeling and Analysis of Thermodynamic Systems) software. In the electrical side, one generator was connected to the Low Pressure (LP) shaft and the other to the High Pressure (HP) shaft. A modified model of the shafts between the engine and the accessory gearbox was created.
2017-09-19
Technical Paper
2017-01-2039
Michael Sielemann, Changsoo Lee, Victor-Marie LeBrun, Chiwoo Ahn, Arnaud Colleoni, Dongkyu Lee, JeongSeok Lee, Anh Nguyen, Katrin Proelss, Hyon Min Yoon
Abstract Thermal management on aircraft has been an important discipline for several decades. However, with the recent generations of high performance aircraft, thermal management has evolved more and more into a critical performance and capability constraint on the whole aircraft level. Fuel continues to be the most important heat sink on high performance aircraft, and consequently the requirements on thermal models of fuel systems are expanding. As the scope of modeling and simulation is widened in general, it is not meaningful to introduce a new isolated modeling and simulation capability. Instead, thermal models must be derived from existing model assets and eventually enable integration across several physical domains. This paper describes such an integrated approach based on the Modelica Fuel System Library and the 3DExperience Platform.
2017-09-19
Technical Paper
2017-01-2108
Denis Buzdalov, Alexey Khoroshilov
Different modelling techniques intended to deal with complexity of modern IMA systems are widely used now. Models can be used to help developers to lay out relevant information structurally. They can also be used to perform different formal analyses on machine-readable models like schedulability analysis, network load checks, WCET for software parts, FTA and FMEA and etc. For some kinds of analyses, special models are created on different stages of development. We suppose that reuse of models for different aspects and development stages is generally a good thing. In some cases it allows to reduce costs on development process; also it allows to make preservation of consistency between models more automatic. We are aware that using the same model for different stages or aspects can cause additional cost in the model maintenance. In this paper we are trying to make a step to further (including practical) research on this topic.
2017-09-19
Technical Paper
2017-01-2158
Fernando Stancato, Luis Carlos dos Santos, Marcelo Pustelnik
Abstract A problem of interest of the aeronautical industry is the positioning of electronic equipment in racks and the associated ventilation system project to guarantee the equipment operational conditions. The relevance of the proper operation of electronic equipment increases considerably when high economical costs, performance reduction and safety are involved. The appropriate operational conditions of the electronic components happen when the working temperature of the equipment installed in the rack is inside a safety project temperature margin. Therefore, the analysis and modelling of heat transfer processes for aircraft rack design becomes mandatory. This paper presents a parametric study considering volumetric and superficial heat generation in electronic equipment within racks in an aircraft. Simulations were performed using the commercial CFD Fluent code and results were compared to experimental data.
2017-09-19
Technical Paper
2017-01-2072
Yilian Zhang, Qingzhen Bi, Nuodi Huang, Long Yu, Yuhan Wang
Interference-fit riveting is a critical fastening technique in the field of aerospace assembly. The fatigue and sealing performance of the rivet joint are determined by the interference-fit level of the rivet joint. As a result, it is of great importance to measure the interference-fit level accurately and effectively. Conventional interference-fit level measurement methods can be divided into direct measurement (destructive test on test-piece) and indirect measurement (off-line dimensional measurement of upset rivet head). Both methods cannot be utilized in automatic riveting. In this paper, an on-line non-destructive measurement method is developed to measure the interference-fit level. By taking full advantage of servo-driving riveting integrated with force measurement, the force-deformation data of the deformed rivet can be obtained in real time. The recognized feature points from the force-deformation data can reflect the height of the upset rivet head.
2017-09-19
Technical Paper
2017-01-2088
Long Yu, Qingzhen Bi PhD, Yilian Zhang, Yuhan Wang
A novel normal measurement device for robotic drilling and countersinking has been developed in this paper. This device is mainly composed of three contact displacement sensors and a spherically compliant clamp pad. The compliance of the clamp pad allows it to be perpendicular to the part when the Multi-Function End Effector (MFEE) drives it to clamp the part surface prior to drilling, while the displacement sensors are used to measure the movement of the clamp pad relative to the MFEE. Once the sensors’ position is calibrated, the rotation angle of the clamp pad can be calculated by the displacement of the sensors. Then, the normal adjustment of MFEE is obtained, and the adjustment process can be achieved by the Tool Center Point (TCP) function of robot. Thus, an innovative method based on laser tracker to identify the position of sensors is proposed.
2017-09-19
Technical Paper
2017-01-2107
Thorsten Kiehl, Jan Philip Speichert, Ethan Higgins, Ralf God
For an “end-to-end passenger experience that is secure, seamless and efficient” the International Air Transport Association (IATA) proposes Near Field Communication (NFC) and a single token concept to be enablers for future digital travel. NFC is a wireless technology commonly utilized in Portable Electronic Devices (PEDs) and contactless smart cards. It is characterized by the following two attributes: a tangible user interface and secured short range communication. While manufacturers are currently adapting PED settings to enable NFC in the flight mode, the integration and use of this technology in aircraft cabins still remains a challenge. There are no explicit qualification guidelines for electromagnetic compatibility (EMC) testing in an aircraft environment available and there is a lack of a detailed characterization of NFC equipped PEDs.
2017-09-19
Technical Paper
2017-01-2025
Eugenio Rodriguez
One of the most important activities associated with the Aerospace and Defense industry is maintenance. Maintainability procedures have a direct impact of safety and operational availability of the system. The processes or procedures used during maintenance activities, whether removing and replacing a component of a system, or even conducting troubleshooting, are generally discrete by design, and in most cases, a maintainer, or a field service representative (FSR), will follow a sequence of steps as part of a maintenance work package or work instruction. Depending on the system, those maintenance activities could be complex, requiring many steps to complete. In order to successfully accomplish complex tasks, generally, one of two possibilities need to exist, either the maintainer is well trained and experienced, or the maintenance work instructions are extremely detailed and precise; both of options can be time consuming and expensive to achieve.
2017-09-19
Technical Paper
2017-01-2017
Catherine Ninah, Brian Strevens, Cole Barcia, Isabelle Labbe, Michael Frenna, Austin Faulconer, Keon Habbaba, Katherine Loundy, Louis Schaefer, Alexa Frost, Andrew Foran, Robert Brown, Luis Rabelo
National Aeronautics and Space Administration (NASA) is preparing for a manned mission to Mars to test the sustainability of civilization on the planet Mars. Our research explores the requirements and feasibility of autonomously producing fuel on Mars for a return trip back to Earth. As a part of NASA’s initiative for a manned trip to Mars, our team’s work creates and analyzes the allocation of resources necessary in deploying a fuel station on this foreign soil. Previous research has addressed concerns with a number individual components of this mission such as power required for fuel station and tools; however, the interactions between these components and the effects they would have on the overall requirements for the fuel station are still a mystery to NASA. By creating a baseline discrete-event simulation model in a simulation software called Simio, the research team has been able to replicate the fuel production process on Mars.
2017-09-19
Journal Article
2017-01-2018
Won Il Jung, Larry Lowe, Luis Rabelo, Gene Lee, Ojeong Kwon
Operator training using a real weapon in a real-world environment is risky, expensive, time-consuming, and restricted to the given environment. The simulator, or a virtual simulation, is usually employed to solve these limitations. As the operator is trained to maximize weapon effectiveness, the effectiveness-focused training can be completed. However, the training was completed in limited scenarios without guidelines to optimize the weapon effectiveness for an individual operator, thus the training will not be effective with a bias. For overcoming this problem, we suggest a methodology on guiding effectiveness-focused training of the weapon operator using big data and Virtual and Constructive (VC) simulations. Big data, which includes structured, unstructured, and semi-structured types, are generated by VC simulations under a variety of scenarios.
2017-09-19
Technical Paper
2017-01-2019
Rakshath G Poojary, Mohammed Ali Jouhar, Abubakar K
Human Powered Helicopter which uses man power to operate. The main aim of this paper is to design commercially available vehicle for an Adventure Sporting under 5-6 lakh Indian Rupees. This structural design is extremely lightweight and strong. The product is designed in such a way that it can be easily assembled and dismantled for transportability and storage. We developed an aero-structural optimization scheme for rotor design, including an aerodynamic model with included ground effect prediction, finite-element analysis and integrated composite failure analysis, and a detailed weight estimation scheme. This was solely build on computer CAD models. This design includes the use of gear box to increase the output. The Aerodynamic analysis was done using CFD and BET (blade element theory-Bhramwell) in MATLAB.
2017-09-19
Technical Paper
2017-01-2021
Numair Mazgaonkar, Andrew Stankovich
For large aerospace assemblies in finite element (FE) analysis problems, contact interaction between the surrounding bodies has to be established to simulate the load transferred between the components, like aircraft engine carrying bracket assemblies, spigots assemblies etc., and understand the effects of interaction between respective parts. In some cases, depending upon geometry of the assembly, the region of study may not be contact area but the stresses acting within the parts themselves. If there is no geometric or material non-linearity in such problems, a new contact formulation method known as Fast Contact can be used in these contact regions. In this method, contact non-linearity could be introduced to simulate the problem but friction between the contacting parts should not be present. Currently, there is a scope for applying this method for solving FE problems in the aerospace and rail industry.
2017-09-19
Journal Article
2017-01-2024
Natasha L. Schatzman, Narayanan Komerath, Ethan A. Romander
The blade crossing event of a coaxial counter-rotating rotor is a potential source of noise and impulsive blade loads. Blade crossings occur many times during each rotor revolution. In previous research by the authors, this phenomenon was analyzed by simulating two airfoils passing each other at specified speeds and vertical separation distances, using the compressible Navier-Stokes solver OVERFLOW. The simulations explored mutual aerodynamic interactions associated with thickness, circulation, and compressibility effects. Results revealed the complex nature of the aerodynamic impulses generated by upper/lower airfoil interactions. In this paper, the coaxial rotor system is simulated using two trains of airfoils, vertically offset, and traveling in opposite directions. The simulation represents multiple blade crossings in a rotor revolution by specifying horizontal distances between each airfoil in the train based on the circumferential distance between blade tips.
2017-09-19
Technical Paper
2017-01-2022
Katherine Loundy, Louis Schaefer, Andrew Foran, Catherine Ninah, Khristopher Bandong, Robert Brown, Hunter Heston, John-Paul Steed, William Young, Mark Heinrich, Luis Rabelo
The future of human exploration in the solar system is contingent on the ability to exploit resources in-situ to produce mission consumables. Specifically, it has become clear that the success of a manned mission to Mars will likely depend on fuel components created on the Martian surface. While several architectures for an un-manned fuel production surface facility on Mars exist in theory, a simulation of the performance and operation of these architectures has not been created. In this paper, the framework describing a simulation of one such architecture is defined. Within this architecture, each component of the base is implemented as a state machine, with the ability to communicate with other base elements as well as a supervisor. An environment supervisor is also created which governs low level aspects of the simulation such as movement and resource distribution, in addition to higher-level aspects such as location selection with respect to operations specific behavior.
2017-09-19
Technical Paper
2017-01-2028
Steven Nolan, Patrick Norman, Graeme Burt, Catherine Jones
Turbo-electric distributed propulsion (TeDP) for aircraft allows for the complete redesign of the airframe so that greater overall fuel and emissions benefits can be achieved. Whilst conventional electrical power systems may be used for smaller aircraft, much larger aircraft are likely to require the use of superconducting electrical power systems to enable the required whole system power density and efficiency levels to be achieved. The TeDP concept requires an effective electrical fault management and protection system. However, the fault response of a superconducting TeDP power system and its components has not been well studied to date, limiting the effective capture of associated protection requirements. For example, with superconducting systems it is the possible that a hotspot is formed on one of the components, such as a cable. This can result in one subsection, rather than all, of a cable quenching.
2017-09-19
Technical Paper
2017-01-2029
Thibaut BILLARD, Cedric Abadie, Bouazza Taghia
The present paper reports non-electrically intrusive partial discharge investigations on aeronautic and electric vehicle motors fed by SiC inverter drive under variable environmental conditions. A representative test procedure and experimental set-up based on operating aeronautic conditions are essential to ensure the accuracy and reliability of partial discharge test on aircraft systems to make informed decisions on insulation system design choice. The aim of this paper is to demonstrate the feasibility of partial discharge test of the insulation system on a different type of motor under such conditions, both electrically and environmentally. To do so, the paper will start by detailing the innovative experimental set-up to be used in the study. It mainly consists in a high-voltage (1000V) inverter drive using SiC components to provide fast rise time surges.
Viewing 61 to 90 of 33398