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Military Vehicle Technology, 2005

2010-09-15
This technical paper collection contains 49 papers detailing military vehicle technology. Topics covered include: reliability growth for military vehicles, upgrading readiness, rapidly installed fluid transfer system, robotic technologies, electrical systems modeling and simulation, nanofluid research, and more.
Journal Article

Study of Wedge-Actuated Continuously Variable Transmission

2021-08-23
Abstract The mechanical efficiency of the current continuously variable transmission (CVT) suffers from high pump loss induced by a high-pressure system. A novel wedge mechanism is designed into the CVT clamp actuation system to generate the majority of clamp force mechanically. Therefore, the hydraulic system can operate at a low-pressure level most of the time, and the pump loss is greatly reduced to improve the CVT’s mechanical efficiency. Through dynamic analysis and design optimization, 90% of clamp force is contributed by the wedge mechanism and the rest of the 10% is generated by a conventional hydraulic system. The optimal design is validated through dynamic modeling using Siemens Virtual.Lab software by simulating the wedge clamp force generation, ratio change dynamics, and system response under tip-in conditions. After that, we built prototype components that target 70% of the clamp force contributed by the wedge mechanism and tested them on a transmission dynamometer.
Journal Article

Nonlinear Iterative Optimization Process for Multichannel Remote Parameter Control

2019-10-14
Abstract In this article, compared with traditional Remote Parameter Control (RPC), the iterative process is improved based on linear transfer function (TF) estimation of the nonlinear dynamic system. In the improved RPC, the iteration coefficient is designed according to the convergence condition of the nonlinear iterative process, so that the convergence level, convergence speed, and iteration stability could be improved. The difference between the traditional and the improved RPC iterative process is discussed, the RPC iterative process of the nonlinear system is analyzed, and channel decoupling for Multi-Input Multi-Output (MIMO) system based on eigen-decomposition of the system TF and linear TF estimation is introduced. It assumes that the eigenvector matrix of the system TF remains the same, and the linear TF in the iterative process is estimated and updated, which is used for iterative calculation.
Journal Article

Critical Inlet Pressure Prediction for Inline Piston Pumps Using Multiphase Computational Fluid Dynamics Modelling

2021-02-15
Abstract Inline piston pumps are extensively used in aircraft hydraulic systems. They can be found in engine-driven large-sized hydraulic pumps and zonal electric motor-driven mid-small sized pumps. Inline piston pumps are positive displacement pumps with variable volumetric flow controls. Positive displacement pumps can provide a variable flow rate over a wide range of suction pressures. Aircraft fly at high altitudes, and therefore these pumps have to work in extreme conditions such as low atmospheric pressure, low temperature. At low inlet pressures, the pump is highly susceptible to cavitation, i.e., insufficient filling capacity. The pressure below which pump flow rate drops drastically is known as critical inlet pressure. Extensive research has been carried out to study cavitation in inline piston pumps.
Standard

Electric Park Brake Sizing

2017-10-16
WIP
J3158
The scope of this new recommended practice should include, but not necessarily be limited to: 1. Define vehicle operating conditions used to drive MOC-EPB actuator design and selection 2. Define brake corner operating conditions (e.g. temperature and state of burnish) used to drive MOC-EPB actuator design and selection 3. Define actuator operating conditions (e.g. temperature, voltage, current limit, and state of wear) used to drive MOC-EPB actuator design and selection 4. Define methodology for addressing part to part variation in performance
Standard

Information Guide for Electric Motors which Drive Hydraulic Pumps

2016-04-25
WIP
AIR6855
This document provides an application guide for electric motors that drive aerospace hydraulic pumps. It provides details of the characteristics of electric motors powered by DC, Fixed Frequency AC, and Variable Frequency AC electrical systems. The applications include both military and commercial aircraft.
Standard

Seals and Wipers for Mechanical and Electromechanical Actuators

2021-04-29
WIP
AIR7379
The purpose of this AIR is to provide a comprehensive description document that displays various examples of low pressure seals and wipers utilized within mechanical and electromechanical actuators. The document is intended as an overview for those specifying or designing actuators in order to compare existing solutions as reference for implementation.
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