Search Results

Newly developed technologies are enabling the design of Unmanned Aerial Vehicles (UAVs) and Micro Air Vehicles (MAVs) with heretofore unrealized capabilities. A tube-launch MAV would allow the increased flexibility to launch an aircraft rapidly without need for a runway or complex launching system, either from a vehicle, installation, or as a man-portable device. The MAV would fill the diameter of the launch tube and deploy aerodynamic lifting and control surfaces after launch. In order to deploy the lifting surfaces the MAV must be capable of deploying control surfaces, negating any tube-imparted roll rate, and developing an optimal flight attitude automatically. An experimental method was developed to characterize the aerodynamics and stability of a blunt body spinning under conditions of roll rate decay in the Clarkson University High Speed Wind tunnel. This method is to be used to evaluate the development of an active roll rate control system for spinning projectiles.

This paper describes a joint SAE automotive and aerospace Recommended Practice SAE J3168 now in development to standardize a process for Reliability Physics Analysis. This is a science-based approach to implement Physics-of-Failure research in conducting durability simulations in a Computer Aided Engineering Environment. It is used to calculate failure mechanism susceptibilities and estimate the likelihood of failure and the expected durability life of Electrical, Electronic and Electromechanical components and equipment, due to stresses such as mechanical shock, vibration, temperature cycling, etc. Reliability Physics Analysis is based on the material science principle of stress driven damage accumulation in materials. The process enables the identification of potential failure risks early in the design phase so that such risks can be designed out in order to efficiently design high reliable and robustness into electronic products.

The applications of unmanned aerial vehicles (UAV) are growing exponentially with advances in hybrid powertrain architecture design tools. The thermal management system (TMS) as an integral part of the powertrain architecture greatly affects the system performance of aerial vehicles. In this study, a comparative analysis of two types of thermal management technologies for a UAV with a series-hybrid powertrain architecture was performed. Conventional TMS based on single-phase (no phase change) cooling technologies using air and liquid (e.g., antifreeze water mixture and oil) as heat transfer fluid has been commonly used because of simple design and operation, although it is considered to be inefficient and bulky. As advanced designs, phase change-based TMS is being slowly adopted although it promises superior cooling capabilities.

This paper summarizes a series of papers investigating the, in use, behavior of lithium-ion cells and packs. Initial efforts concentrated on cell data 1, 2, 3 and 4 and were reported in 2003 through 2006. Follow-on efforts concentrated on battery pack data 5, 6 and 7 and were reported in 2007 through 2008. In these efforts lithium-ion cells and batteries (4P4S, 2P4S and 4S) were cycled at various conditions. Battery packs, fully augmented with control and monitoring electronics, were subjected to an external heat source at varying intensities which were applied to the base of the battery during both charge and discharge. This heat source effectively heated one cell of the battery string.

A study was made to determine the effectiveness of low power wind energy harvesting for mobile applications. Experimental and simulated data has shown that harvesting of alternative energy resources is viable for potential mobile applications. This conducted study incorporated a mobile configuration consisting of a wind-photovoltaic hybrid in concert with a vehicle generator. The study has demonstrated an improvement in overall efficiency of the power generation system.

In intelligent surveillance and reconnaissance (ISR) missions, multiple autonomous vehicles, such as unmanned ground vehicles (UGVs) or unmanned aerial vehicles (UAVs), coordinate with each other for efficient information gathering. These vehicles are usually battery-powered and require periodic charging when deployed for continuous monitoring that spans multiple hours or days. In this paper, we consider a mobile host charging vehicle that carries distributed sources, such as a generator, solar PV and battery, and is deployed in the area where the UAVs and UGVs operate. However, due to uncertainties, the state of charge of UAV and UGV batteries, their arrival time at the charging location and the charging duration cannot be predicted accurately.