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Technical Paper

Actively Articulated Wheeled Architectures for Autonomous Ground Vehicles - Opportunities and Challenges

2023-04-11
2023-01-0109
Traditional ground vehicle architectures comprise of a chassis connected via passive, semi-active, or active suspension systems to multiple ground wheels. Current design-optimizations of vehicle architectures for on-road applications have diminished their mobility and maneuverability in off-road settings. Autonomous Ground Vehicles (AGV) traversing off-road environments face numerous challenges concerning terrain roughness, soil hardness, uneven obstacle-filled terrain, and varying traction conditions. Numerous Active Articulated-Wheeled (AAW) vehicle architectures have emerged to permit AGVs to adapt to variable terrain conditions in various off-road application arenas (off-road, construction, mining, and space robotics). However, a comprehensive framework of AAW platforms for exploring various facets of system architecture/design, analysis (kinematics/dynamics), and control (motions/forces) remains challenging.
Standard

Automotive Gear Lubricants for Commercial and Military Use

2021-01-27
HISTORICAL
J2360_202101
The gear lubricants covered by this standard exceed American Petroleum Institute (API) Service Classification API GL-5 and are intended for hypoid-type, automotive gear units, operating under conditions of high-speed/shock load and low-speed/high-torque. These lubricants may be appropriate for other gear applications where the position of the shafts relative to each other and the type of gear flank contact involve a large percentage of sliding contact. Such applications typically require extreme pressure (EP) additives to prevent the adhesion and subsequent tearing away of material from the loaded gear flanks. These lubricants are not appropriate for the lubrication of worm gears. Appendix A is a mandatory part of this standard. The information contained in Appendix A is intended for the demonstration of compliance with the requirements of this standard and for listing on the Qualified Products List (QPL) administered by the Lubricant Review Institute (LRI).
Journal Article

Design of a 1.2 kW Interleaved Synchronous Buck Converter for Retrofit Applications in Aviation Systems

2020-10-19
Abstract Presently, 270 V direct current (DC) systems replace older 28 V DC voltage systems in both the civil and military aviation industry due to the requirement for more electrical power needs on board. Therefore, the existing avionics require retrofitting. The conversion from 270 V to 28 V appears to be quite promising for both old and new systems. This study aims to design an interleaved synchronous modular buck converter topology as a candidate for these requirements. Calculations for the converter design are conducted considering aviation standards. Switching with pulse-width modulation (PWM) is used to control the power converter. A double-loop feedback control system based on voltage and current feedback is designed. Therefore, the buck converter circuit with 1145 W power output is proposed, which supplies a 28 V and 41 A DC output from a 270 V DC input. The concept is verified using simulations and hardware-in-the-loop (HIL) experimental results.
Training / Education

Energy Systems Transformation

Anytime
Introduction to Energy System Transformation: In this course you will be introduced to the historical drivers and trends that started the energy transition, as well as consequences of the new energy shift towards a zero-emission society and discuss the challenges and opportunities arising from this shift in energy sources focus. You will then be addressed as a citizen consuming energy. You will explore how everyday energy consumption fluctuates and how personal behaviors can significantly change the amount of energy that is used. Lastly, you will learn about advanced visualization for energy consumption.
Technical Paper

Influence of the distances between the axles in the vertical dynamics of a military vehicle equipped with magnetorheological dampers

2018-09-03
2018-36-0232
While traveling on any type of ground, the damper of a vehicle has the critical task of attenuating the vibrations generated by its irregularities, to promote safety, stability, and comfort to the occupants. To reach that goal, several passive dampers projects are optimized to embrace a bigger frequency range, but, by its limitations, many studies in semiactive and active dampers stands out by promoting better control of the vehicle dynamics behavior. In the case of military vehicles, which usually have more significant dimensions than the common ones and can run on rough or unpaved lands, the use of semi-active or active dampers reveals itself as a promising alternative. Motivated by that, the present study performs an analysis of the vertical dynamics of a wheeled military vehicle with four axles, using magnetorheological dampers. This study is made using a configuration of the distances between the axles of the vehicle, which is chosen from five available options.
Magazine

SAE Truck & Off-Highway Engineering: April 2018

2018-04-05
Connectivity takes center stage Telematic links have become the norm, helping fleet owners and operators improve efficiency and letting OEMs predict component failures. More power, less noise, fewer emissions These key attributes drive development of new generators both big and small. TARDEC pursues advanced power generation U.S. Army, GM collaborate on fuel-cell-generated electricity to power the vehicle's propulsion system and onboard electronics, while providing off-vehicle power via an Exportable Power Take-Off unit. Developing an alternative engine concept Ricardo's CryoPower engine leverages two unique combustion techniques for reduced emissions and fuel consumption-liquid nitrogen and split combustion. Long-haul trucking and stationary power generation will be the first beneficiaries of the technologies. Technology time-warp The road to autonomous driving has been under construction for decades, as showcased by SAE's Mobility History Committee at the 2018 WCX in Detroit.
Technical Paper

VISION: Vehicle Infrared Signature Aware Off-Road Navigation

2024-04-09
2024-01-2661
Vehicle navigation in off-road environments is challenging due to terrain uncertainty. Various approaches that account for factors such as terrain trafficability, vehicle dynamics, and energy utilization have been investigated. However, these are not sufficient to ensure safe navigation of optionally manned ground vehicles that are prone to detection using thermal infrared (IR) seekers in combat missions. This work is directed towards the development of a vehicle IR signature aware navigation stack comprised of global and local planner modules to realize safe navigation for optionally manned ground vehicles. The global planner used A* search heuristics designed to find the optimal path that minimizes the vehicle thermal signature metric on the map of terrain’s apparent temperature. The local planner used a model-predictive control (MPC) algorithm to achieve integrated motion planning and control of the vehicle to follow the path waypoints provided by the global planner.
Standard

Wheels/Rims - Military Vehicles Test Procedures and Performance Requirements

2023-07-14
CURRENT
J1992_202307
This SAE Recommended Practice provides minimum performance requirements and uniform laboratory procedures for fatigue testing of disc wheels, demountable rims, and bolt-together divided wheels intended for normal highway use on military trucks, buses, truck-trailers, and multipurpose vehicles. Users may establish design criteria exceeding the minimum performance requirement for added confidence in a design. For other (non-military) wheels and rims intended for normal highway use on trucks and buses, refer to SAE J267. For wheels intended for normal highway and temporary use on passenger cars, light trucks, and multipurpose vehicles, refer to SAE J328. For wheels used on trailers drawn by passenger cars, light trucks, or multipurpose vehicles, refer to SAE J1204. This document does not cover off-highway or other special application wheels and rims.
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