Tech Briefs

Aerodynamic Modeling of a Flapping Wing Unmanned Aerial Vehicle

The phenomenon of flapping wing flight in nature has been studied for centuries. Recently, flapping flight for unmanned aerial vehicle (UAV) applications has become of interest. Flapping wing flight offers many potential advantages over traditional fixed- and rotary-wing aircraft. Fixed-wing UAVs have the advantages of long range and endurance, and high payload capabilities; however, they require high forward flight speeds and most configurations cannot hover, which makes them difficult to control in confined spaces.

Posted in: Briefs, Aerospace, Defense, Electronics & Computers, Information Technology, Airframes, Wings, Computer simulation, Aerodynamics, Unmanned aerial vehicles

Queuing Model for Supervisory Control of Unmanned Autonomous Vehicles

One critical aspect in developing a quantitative model of unmanned autonomous vehicle (UAV) operator and system performance has been to adopt a task-centric approach to interface design that entails an explicit representation of actions or tasks that need to be performed by the operator. The representation of work in terms of a task serves as a trace in the system that enables designers to track workload in addition to the task progress and flow of tasks among team members. In supervisory control, the focus is the flow of tasks (work) through a system that is composed of human servers and automated servers (software agents).

Posted in: Briefs, Aerospace, Defense, Electronics & Computers, Information Technology, Computer simulation, Human machine interface (HMI), Autonomous vehicles, Unmanned aerial vehicles

Real-Time, High-Fidelity Simulation of Autonomous Ground Vehicle Dynamics

Integrated simulation capabilities that are high-fidelity, fast, and have scalable architecture are essential to support autonomous vehicle design and performance assessment for the Army’s growing use of unmanned ground vehicles (UGVs). A mobility simulation of an autonomous vehicle in an off-road scenario was developed using integrated sensor, controller, and multibody dynamics models.

Posted in: Briefs, Aerospace, Defense, Electronics & Computers, Information Technology, Computer simulation, Architecture, Autonomous vehicles, Military vehicles and equipment, Off-highway vehicles and equipment

Software for Material/Structural Characterization Across Length Scales

Synthetic and natural micro-architectures occur frequently, and multiphase functionally graded composites are becoming increasingly popular for applications requiring optimized/tailored material properties. When dealing with such materials computationally, one issue that immediately arises is the analysis of the mechanical properties of macroscopically inhomogeneous multi-scale structures. The bulk response of these structures can be determined by performing full finite element analysis (FEA); that is, with the entire geometry discretized at a resolution high enough to accurately model the smallest length scale of interest. However, these full models may easily exceed hundreds of millions, or potentially billions, of degrees of freedom, and solving problems of this magnitude may only be possible with the use of supercomputing facilities.

Posted in: Briefs, Aerospace, Information Technology, Computer software / hardware, Composite materials, Materials properties

Model Development Using Accelerated Simulations of Hypersonic Flow Features

Currently, the two main computational tools used by the aerothermodynamics community to model hypersonic flows are Computational Fluid Dynamics (CFD), and the direct simulation Monte Carlo (DSMC) particle method. Both use essentially the same physical models for rotational-vibrational excitation and dissociation phenomenon, which are based on a limited number of near-equilibrium experiments performed at low temperatures.

Posted in: Briefs, Aerospace, Defense, Information Technology, Computational fluid dynamics, Thermal testing, Aerodynamics

Chrono: A Parallel Physics Library for Rigid-Body, Flexible-Body, and Fluid Dynamics

The Chrono::Engine software is a general-purpose simulator for three-dimensional multi-body problems. Specifically, the code is designed to support the simulation of very large systems such as those encountered in granular dynamics, where the number of interacting elements can be in the millions. Target applications include tracked vehicles operating on granular terrain, or the Mars rover operating on discrete granular soil.

Posted in: Briefs, Aerospace, Defense, Software, Computer software / hardware, Particulate matter (PM), Off-highway vehicles and equipment, Spacecraft

Terrain Model as an Interface for Real-Time Vehicle Dynamics Simulations

In order to enable off-road vehicle dynamics analysis simulations when traveling on soft soil, a deformable Vehicle Terrain Interface (VTI) model that interfaces with existing vehicle and tire dynamics models was developed. It is modularized to be interfaced to a multibody dynamics vehicle that supports the Standard Tire Interface (STI). Any tire model can be used that supports the STI as well; currently, both rigid and flexible tire models are supported.

Posted in: Briefs, Aerospace, Defense, Information Technology, Tires and traction, Computer simulation, Off-highway vehicles and equipment, Vehicle dynamics