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Journal Article

Algorithm Development for Avoiding Both Moving and Stationary Obstacles in an Unstructured High-Speed Autonomous Vehicular Application Using a Nonlinear Model Predictive Controller

2020-10-19
Abstract The advancement in vision sensors and embedded technology created the opportunity in autonomous vehicles to look ahead in the future to avoid potential obstacles and steep regions to reach the target location as soon as possible and yet maintain vehicle safety from rollover. The present work focuses on developing a nonlinear model predictive controller (NMPC) for a high-speed off-road autonomous vehicle, which avoids undesirable conditions including stationary obstacles, moving obstacles, and steep regions while maintaining the vehicle safety from rollover. The NMPC controller is developed using CasADi tools in the MATLAB environment. The CasADi tool provides a platform to formulate the NMPC problem using symbolic expressions, which is an easy and efficient way of solving the optimization problem. In the present work, the vehicle lateral dynamics are modeled using the Pacejka nonlinear tire model.
Journal Article

Development and Optimization of Formation Flying for Unmanned Aerial Vehicles Using Particle Swarm Optimization Based on Reciprocal Velocity Obstacles

2022-09-23
Abstract In this article, a formation flying technique designed for a multiple unmanned aerial vehicles (multi-UAV) system to provide low-cost and efficient solution for civilian and military applications is presented. First, a modular leader-follower formation algorithm was developed to accomplish the formation flying with off-the-shelf low-cost components and sensors. Second, a proportional-integral-derivative (PID) controller was utilized for velocity control of the UAVs to maintain the tight formation. Third, a particle swarm optimization-optimized reciprocal velocity obstacles (PSO-RVO) algorithm was utilized for obstacles avoidance and collision avoidance between the UAVs while navigating, with the aid of sonar ranging sensors onboard. The formation flying algorithm developed was tested through both simulation and experiment using two quadcopters with global positioning system (GPS) signals.
Technical Paper

Decomposition and Coordination to Support Tradespace Analysis for Ground Vehicle Systems

2022-03-29
2022-01-0370
Tradespace analysis is used to define the characteristics of the solution space for a vehicle design problem enabling decision-makers (DMs) to evaluate the risk-benefit posture of a vehicle design program. The tradespace itself is defined by a set of functional objectives defined by vehicle simulations and evaluating the performance of individual design solutions that are modeled by a set of input variables. Of special interest are efficient design solutions because their perfomance is Pareto meaning that none of their functional objective values can be improved without decaying the value of another objective. The functional objectives are derived from a combination of simulations to determine vehicle performance metrics and direct calculations using vehicle characteristics. The vehicle characteristics represent vendor specifications of vehicle subsystems representing various technologies.
Journal Article

A Novel Flight Dynamics Modeling Using Robust Support Vector Regression against Adversarial Attacks

2023-03-24
Abstract An accurate Unmanned Aerial System (UAS) Flight Dynamics Model (FDM) allows us to design its efficient controller in early development phases and to increase safety while reducing costs. Flight tests are normally conducted for a pre-established number of flight conditions, and then mathematical methods are used to obtain the FDM for the entire flight envelope. For our UAS-S4 Ehecatl, 216 local FDMs corresponding to different flight conditions were utilized to create its Local Linear Scheduled Flight Dynamics Model (LLS-FDM). The initial flight envelope data containing 216 local FDMs was further augmented using interpolation and extrapolation methodologies, thus increasing the number of trimmed local FDMs of up to 3,642. Relying on this augmented dataset, the Support Vector Machine (SVM) methodology was used as a benchmarking regression algorithm due to its excellent performance when training samples could not be separated linearly.
Training / Education

Polymers Bundle

Anytime
This course discusses the properties and applications of thermoplastics, including an overview of the amorphous and semi-crystalline molecular regions found in thermoplastics, and describes common processing methods for thermoplastics, such as injection molding and extruding. Thermosets This course introduces participants to the key characteristics and types of thermosets as well as common processing methods. Courses listed above are available only as part of a TooliingU bundle.  Custom bundles of any five or more ToolingU courses are available upon request as a Corporate Learning Solution.
Training / Education

Introduction to Materials Bundle

Anytime
The following six eLearning courses are included in the Introduction to Materials bundle.  Each course is approximately one-hour in duration. See Topics/Outline for additional details. Introduction to Physical Properties  This course provides an an overview of manufacturing materials and their physical properties, including thermal, electrical, and magnetic properties and introduces volumetric characteristics, such as mass, weight, and density.
Magazine

Tech Briefs: April 2018

2018-04-01
Laser Detecting Systems Enhancing Survivability and Lethality on the Battlefield Designing With Plastics for Military Equipment Engine Air-Brakes Paving the Way to Quieter Aircraft Nett Warrior Enhancing Battlefield Connectivity and Communications XPONENTIAL 2018 - An AUVSI Experience Communications in Space: A Deep Subject First Air-Worthy Metal-Printed RF Filter Ready for Takeoff Validation of Automated Prediction of Blood Product Needs Algorithm Processing Continuous Non-Invasive Vital Signs Streams (ONPOINT4) Using a combination of non-invasive sensors, advanced algorithms, and instruments built for combat medics could reduce hemorrhaging and improve survival rates. Calculation of Weapon Platform Attitude and Cant Using Available Sensor Feedback Successful development of mobile weapon systems must incorporate operation on sloped terrain.
Magazine

Tech Briefs: August 2018

2018-08-01
Designing a High-Speed Decoy Unmanned Aerial Vehicle (UAV) Using Thermoplastics in Aerospace Applications In-Flight Real-Time Avionics Adaptation Using Turbine Flow Meters for Aerospace Test and Measurement Applications Communicating from Space: The Front End of Multiscale Modeling Laser-Based System Could Expand Space-to-Ground Communication Hydraulic Testing of Polymer Matrix Composite 102mm Tube Section Research could lead to development of a composite material that can be processed at a low temperature and still be used at 1000°F. Permeation Tests on Polypropylene Fiber Materials Study attempts to determine if polypropylene nanofiber materials can be used in air filtration systems to remove toxic vapors. Inter-Laboratory Combat Helmet Blunt Impact Test Method Comparison Ensuring consistent test methods could reduce the risk of head injuries.
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