Mechanical Components

Parallel Hybrid Vehicles Using Fuzzy Logic Control

A fuzzy logic controller for hybrid vehicles with parallel configuration was proposed. Using the state-of-charge (SOC) of the energy storage, the driver command, and the motor/generator speed, a set of rules was developed. The fuzzy logic controller can determine the split between the electric motor and the internal combustion engine to achieve better fuel economy and low emission performance without losing vehicle performance.

Posted in: Briefs, Mechanical Components, Fuzzy logic, Architecture, Hybrid electric vehicles, Vehicle performance

Membrane Pump for Synthetic Muscle Actuation

A synthetic muscle has been developed that uses inflatable balloons to produce a tensile force from a positive pressurization. Mechanical supply and ducting is used to provide the required pressurization. However, the mechanical supply and ducting that is currently used is limited in several respects. To optimize rate of actuation, it is desirable to minimize the cell volume and to maximize the area through which fluid is forced into the cell. Ideally, a fully closed cell that is inflated through some mass transfer process that takes place through the cell boundary would lead to a maximum cell response rate.

Posted in: Briefs, Mechanical Components, Architecture, Sensors and actuators, Pumps, Marine vehicles and equipment

Nonlinear, High-Fidelity, Aeroelastic Analysis for Novel Configurations

Efforts to develop morphing air vehicles with multiple mission capabilities have recently been undertaken by several research teams, including NASA’s Aircraft Morphing program and the Defense Advanced Research Projects Agency’s (DARPA) Morphing Aircraft Structures program. One such morphing wing structure is the folding wing concept. With multiple individually articulated sections, various wing geometries can be achieved in-flight, allowing for multirole missions with the same aircraft.

Posted in: Briefs, Mechanical Components, Wings, Vehicle styling, Aircraft, Military aircraft

Designing a Sensorless Torque Estimator for Direct Torque Control of an Induction Motor

Induction motors often are the preferred choice among industrial motors due to the modern power electronics that improve their speed control. Vitally important for the speed control of a motor is the accurate estimation of the magnetic flux and the electromagnetic torque. Knowing the electromagnetic torque of a motor, one is able to control it and thus monitor the speed faster and more stably.

Posted in: Briefs, Mechanical Components, Measurements, Power electronics, Industrial vehicles and equipment

Lightcraft Propulsion for Launching a Small Satellite

A study of lightcraft propulsion systems in general has led to the conception and analysis of such a system for launching a small (having a mass no more than a few kilograms) satellite into a low orbit around the Earth. This study built on theoretical and experimental investigations of the feasibility of lightcraft, performed by a number of researchers during the past two decades. The word “lightcraft” signifies an aircraft or spacecraft that derives its propulsive energy from a laser beam aimed toward it from an external platform that, for the purpose of the present study, would be a ground station.

Posted in: Briefs, Mechanical Components, Mirrors, Lasers, Propellants, Satellites

Eccentric Mounting and Adjustment System for Belt-Driven Devices

This design relates to an eccentric mounting and adjustment (EMA) system for belt driving, or for belt-driven devices, that is installed and operated within the restricted confines of an engine compartment, typically a motor vehicle. It satisfies two essential requirements for automotive devices driven by an endless flexible belt, including a reliable mounting to the engine block assembly, and a continuous provision of a proper amount of tension to the belt for either driving or driven devices. As a result, there is minimal wear and tear on device bearings and the belt, which reduces operational failures and assures maximum efficiency for these devices.

Posted in: Briefs, Mechanical Components, Mountings, Engine components

Developing Fleets of Autonomous Underwater Vehicles

Autonomous underwater vehicles (AUVs) have a demonstrated capability to collect valuable data for scientific and military purposes. Historically, individual vehicles have been used. To reduce the overall time and cost of acquiring data over large areas, multiple vehicles must be used. A fleet of five AUVs, capable of underwater commendation, was fabricated. These AUVs include small submarines, referred to as “swimmers,” and small, two-tracked vehicles, referred to as “crawlers.” The control and communication algorithms developed in this work will enable AUVs to use formations to search for mines and to communicate with each other in order to implement cooperative behavior. Languages and logics were developed to enable collaborative operations among the vehicles.

Posted in: Briefs, Mechanical Components, Communication protocols, Electronic control systems, Fleet management, Autonomous vehicles, Marine vehicles and equipment

Stability Analysis of Distributed Engine Control Systems

Full Authority Digital Engine Control (FADEC), based on a centralized architecture framework, is being widely used for gas turbine engine control. However, current FADEC is not able to meet the increased burden imposed by the advanced intelligent propulsion system concepts. This has necessitated development of the Distributed Engine Control (DEC) system. FADEC based on Distributed Control Systems (DCS) offers modularity, improved control sys-tem prognostics, and fault tolerance, along with reducing the impact of hardware obsolescence.

Posted in: Briefs, Mechanical Components, Architecture, Performance upgrades, Engine control systems, Gas turbines

Using a Steering Shaping Function to Improve Human Performance in By-Wire Vehicles

Currently, there is a performance issue regarding vehicle control at higher speeds for some indirect-vision, by-wire military vehicles; that is, those vehicles in which mechanical links between the driver and control devices are replaced by electronic or computerized signals. Work has been performed to assess the current state of knowledge regarding the shaping function. The overall goal was to identify design parameters critical to improving the current by-wire implementation for military tactical vehicles, and to ultimately optimize system (i.e., human-vehicle) performance for the execution of secure mobile operations.

Posted in: Briefs, Mechanical Components, Steer-by-wire, Human machine interface (HMI), Military vehicles and equipment, Vehicle dynamics

Sensing for Controls and Propulsion Health Management in Turbine Engines

Advances in engine performance and reliability require sensor components that operate reliably under extreme engine operating conditions (e.g., takeoff, max thrust) and in harsh environments (e.g., high temperature and radiation). The design of advanced controls and Propulsion Health Man agement (PHM) also depend on the use of components with increased susceptibility to atmospheric radiation. Current and future engine operating temperature environments that provide major challenges in sensor design for control and propulsion health management are being explored.

Posted in: Briefs, Mechanical Components, Sensors and actuators, Diagnostics, Gas turbines, Durability, Reliability