Seeded Fault Testing of Military Ground Vehicles as a Pathway to Condition Based Maintenance

Author(s):  
Matthew J. Hillegass ◽  
Eric L. Rabeno

The performance of military ground vehicle systems is being degraded due to high operation tempo and exposure to extreme environments while performing in-theater service. To address this issue, the US Army is implementing a policy of Condition Based Maintenance which is supported by the Army Material System Analysis Activity (AMSAA). The vision of this policy is to base the maintenance of systems upon the actual condition of the system and not upon time- or distance-based schedules. This capability will be enabled by the application of usage, diagnostic and prognostic processes executed on a Health and Usage Monitoring System (HUMS) installed on these vehicle systems. A thorough understanding of the ways in which the system condition is degenerated and the ability of the HUMS to detect, identify, and communicate all conditions that require maintenance in a timely manner are key requirements of these processes. Seeded Fault Testing is the critical means of fulfilling these requirements. A joint Seeded Fault Testing project between AMSAA and the US Army Aberdeen Test Center (ATC) has been initiated to gain a thorough understanding of ground vehicle system condition degeneration and HUMS implementation of products and processes that can accurately identify and communicate it. A military vehicle underwent exhaustive testing in support of this project. The vehicle was subjected to specific use scenarios while carefully controlled faults are induced in engine, transmission, and other key mechanical subsystems that would degrade vehicle performance and degenerate system condition. The vehicle’s induced faults included lowered coolant levels to simulate leakage, restriction of air flow across radiators and filters to simulate dust and debris accumulation, and lowered transmission and engine oil levels to simulate leakage and usage. The objective of this project was to use the results from the seeded fault tests to establish critical thresholds, trends, and patterns that will be the basis of the creation and implementation of real-time HUMS-based algorithms that predict faults, warn operators and maintainers of imminent failures, and provide a sound foundation for Condition Based Maintenance.

2000 ◽  
Author(s):  
David D. Gunter ◽  
Michael D. Letherwood

Abstract The US Army Tank-automotive and Armaments Command (TACOM) has the mission of procuring and managing the US Army’s fleet of wheeled and tracked vehicles. TACOM’s Tank Automotive Research, Development and Engineering Center (TARDEC) provides engineering and scientific support directed at maximizing the capability of all Department of Defense (DOD) ground vehicle systems and ensuring the safety of their personnel. In order to reduce the time required to deploy troops and equipment, engineers and scientists at TARDEC have been investigating modifications to ground vehicles that lead to overall increases in performance, especially in the areas of off-road mobility, and on-road stability and handling. This paper describes an effort to assess the dynamic performance of a track laying (tracked) Recovery Vehicle towing a disabled tracked vehicle whose weight is approximately equal to that of the Recovery Vehicle. Specifically, this paper will describe techniques employed to develop a 3-dimensional dynamic model of the vehicle combination, and apply the model to evaluate towing performance of the recovery vehicle. It also describes measures aimed at minimizing incidences of jackknifing when braking on downhill slopes, as well as vehicle design modifications that were modeled and simulated in efforts to reduce the combination’s jackknife vulnerability. These modifications included tow bar schemes that locked-out inter-vehicle yaw, and external surge brakes mounted on the towed vehicle. Techniques used to model and simulate the tractive effort available to the Recovery Vehicle on varied soil types are described as are analyses used to determine the combination’s ability to climb grades. Vehicle modifications aimed at increasing the tractive effort available, such as tow bar pitch orientation and track shoe geometry changes are also described.


Author(s):  
Kishore Sai Vejju ◽  
Jeffrey S. Freeman

Abstract This paper presents concepts involved in the theory and implementation of a vehicle body and suspension modeling tool as part of the software development for the National Advanced Driving Simulator (NADS). The NADS will be a state-of-the-art, operator-in-the-loop ground vehicle simulator, which can be applied to both human factors and vehicle virtual prototyping studies. By applying the modeling tool developed in this study, vehicle kinematic models can be easily created and tested, either using off-line engineering analysis packages or using operator-in-the-loop simulators, such as the NADS. Vehicles are complex systems containing multiple bodies, joints and force generating elements. Manually modeling these systems for kinematic and/or dynamic analysis is tedious and prone to errors. This creates a need for a modeling tool which reduces modeling time, increases modeling accuracy and is easy to use. This paper discusses the concepts involved in developing a modeling tool for the topology analysis and assembly of the multibody vehicle model. Suspension system modeling is briefly described, along with an example employing the US Army HMMWV vehicle.


2020 ◽  
pp. 304-312

Background: Insult to the brain, whether from trauma or other etiologies, can have a devastating effect on an individual. Symptoms can be many and varied, depending on the location and extent of damage. This presentation can be a challenge to the optometrist charged with treating the sequelae of this event as multiple functional components of the visual system can be affected. Case Report: This paper describes the diagnosis and subsequent ophthalmic management of an acquired brain injury in a 22 year old male on active duty in the US Army. After developing acute neurological symptoms, the patient was diagnosed with a pilocytic astrocytoma of the cerebellum. Emergent neurosurgery to treat the neoplasm resulted in iatrogenic cranial nerve palsies and a hemispheric syndrome. Over the next 18 months, he was managed by a series of providers, including a strabismus surgeon, until presenting to our clinic. Lenses, prism, and in-office and out-of-office neurooptometric rehabilitation therapy were utilized to improve his functioning and make progress towards his goals. Conclusions: Pilocytic astrocytomas are the most common primary brain tumors, and the vast majority are benign with excellent surgical prognosis. Although the most common site is the cerebellum, the visual pathway is also frequently affected. If the eye or visual system is affected, optometrists have the ability to drastically improve quality of life with neuro-optometric rehabilitation.


Author(s):  
D.B. Izyumov ◽  
E.L. Kondratyuk

The article discusses issues related to the development and use of training means and facilities in order to improve the level of training of US Army personnel. An overview of the main simulators used in the US Armed Forces at present is given, and the prospects for the development of the United States in this area are presented.


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