Browsing by Subject "Electrical Mechanical Systems"
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Item Active Suspension System Energy and Power Requirements for Military Applications(1995-10) Beno, J.H.; Hoogterp, F.B.; Weeks, D.A.Item Attributes of direct measurement of inductance in a loop detector for traffic control(2004-03) Datta, S.; Carroll, J.; V. Petit, B. Sathyamangalam, R. Hebner, M. GradyInductive loop detectors for traffic control conventionally operate by sensing a resonant frequency shift when a vehicle passes over a loop. Using a digital system to measure the inductance as a function of time, better sensitivity and additional capability is available. This includes the ability to use both amplitude and frequency domain information to separate signals produced by vehicles that introduce only small interactions with the loop from signals due to vehicles in adjacent lanes. The detection scheme also permits an alternative approach for detecting bicycles and the option of placing detectors farther from an intersection to better control high speed traffic.Item A Comparison of Controller Designs for an Active, Electromagnetic, Offroad Vehicle Suspension System Traveling at High Speed(Society of Automotive Engineers, Inc., 1998) Schuetze, K.T.; Beno, J.H.; Weldon, W.F.; Sreenivasan, S.V.This paper discusses controller development for an active, off-road vehicle suspension system. A brief review of electronic filters and their characteristics is used to provide insight on the difficulties of designing a control algorithm for negotiating hilly and rough terrain at higher speeds. Two controller designs are presented. One was designed by pole placement and causes the suspension response to approximate a Type 1 Chebychev filter. The other was designed using constrained optimization. A comparison and discussion of simulation results leads to the conclusion that the suspension should be adaptively or predictively controlled for arbitrary terrain and velocity conditions.Item Control System for Quarter Car Heavy Tracked Vehicle Active Electromagnetic Suspension(Society of Automotive Engineers, Inc., 1997-02) Weeks, D. A.; Beno, J. H.; Bresie, D. A.; Guenin, A.Researchers at The University of Texas Center for Electromechanics recently completed design, fabrication, and preliminary testing of an Electromagnetic Active Suspension System (EMASS). The EMASS program was sponsored by the United States Army Tank Automotive and Armaments Command Center (TACOM) and the Defense Advanced Research Projects Agency (DARPA). A full scale, single wheel mockup of an M1 tank suspension was chosen for evaluating the EMASS concept. The specific goal of the program was to increase suspension performance so that cross-country terrain could be negotiated at speeds up to 17.9 m/s (40 mph) without subjecting vehicle occupants to greater than 0.5 gee rms. This paper is a companion paper to a previous SAE publication that developed suspension theory and control approaches. This paper focuses on hardware implementation, software implementation, and experimental results.Item Electromechanical Suspension for Combat Vehicles(Society of Automotive Engineers, Inc., 1995) Beno, J.H.; Hoogterp, F.B.; Bresie, D.A.; Weeks, D.A.; Ingram, S.K.; Weldon, W.F.The use of electromechanical actuators for an active suspension on a main battle tank is investigated. A novel approach to the development of the active suspension control algorithms is presented along with simulation results to evaluate the electromechanical design requirements. The optimal electromechanical actuator design is described along with simulated performance results for a one roadwheel station electromechanical active suspension. Follow-up plans for the laboratory testing of a single wheel station system are also included.Item An Energy Efficient Electromagnetic Active Suspension System(Society of Automotive Engineers, Inc., 1997-02) Hoogterp, F.B.; Beno, J.H.; Weeks, D.A.The technology thrust to develop an effective electromagnetic actuator for application in an active suspension system has precipitated a fresh look at the active control schemes in an effort to reduce the required force levels of the actuator. The resulting “near constant force” control algorithm is described and its ability to greatly reduce vehicle sprung mass motion is documented through simulation and single wheel station laboratory test stand results. The vehicle power and energy requirements associated with this unwanted vehicle vertical are analyzed and comparisons between the corresponding passive and active systems are presented. The success of the active system leads naturally to the conclusion that a passive suspension equipped vehicle will become power limited at a much lower speed than will this active system when traversing severe cross-country terrain.Item Intelligent Estimation of System Parameters for Active Vehicle Suspension Control(Society of Automotive Engineers, Inc., 1999) Buckner, G.D.; Schuetze, K.T.; Beno, J.H.Active control of vehicle suspension systems typically relies on linear, time-invariant, lumped-parameter dynamic models. While these models are convenient, nominally accurate, and tractable due to the abundance of linear control techniques, they neglect potentially significant nonlinearities and time-varying dynamics present in real suspension systems. One approach to improving the effectiveness of such linear control applications is to introduce time and spatially dependent coefficients, making the model adaptable to parameter variations and unmodeled dynamics. In this paper, the authors demonstrate an intelligent parameter estimation approach, using structured artificial neural networks, to continually adapt the lumped parameters of a linear, quarter-car suspension model. Results are presented for simulated and experimental quarter-vehicle suspension system data, and clearly demonstrate the viability of this approach.Item Loss Reduction Strategies in Design of Magnetic Bearing Actuators for Military Vehicle Applications(IEEE, 2005-05) Pichot, M.A.; Driga, M.Advanced energy storage systems for future military vehicles may include the use of high speed rotating machines in which magnetic bearing systems are used for rotor support. High speed machines commonly require rotors to operate in evacuated enclosures, complicating efforts to cool rotor components, since convective heat transfer is not possible in vacuum environments. As a result, it is important to minimize magnetic bearing losses to avoid excessive temperatures in high strength rotor components. This paper discusses two design strategies intended to minimize losses in active magnetic bearing actuators.Item Simulation and Field Verification of Vehicle-Loop Interactions(0000-00-00) Petit, V.; Hebner, R.E.; Grady, M.; Datta, S.; Carroll, J.; Sathyamangalam, B.Inductive sensors are used worldwide for traffic control. These sensors consist of a loop or loops of wire embedded in the pavement. The loops are connected to electronic control circuits that convert changes in loop inductance to signals to control traffic lights or to monitor traffic. This work describes a simulation approach that permits reliable calculation of the response of loops of various geometries to various types of vehicles. The simulation models both the loop and the vehicles with a set of filaments of finite length. The simulation approach was validated using two different loop geometries and various types of vehicles. The simulation was developed to assist in the selection of a loop geometry for a particular application or to assess the likely behavior of hypothetical loops. As it is based on a fundamental description of the vehicle-loop interaction, the simulation approach is also expected to be useful in other investigations of loop responses.Item Thermal Evaluation of High Voltage Hermetic Motors Experiencing Recurrent Insulation Failures(0000-00-00) Liu, H-P.; Herbst, J.D.; Jordan, H.E.A high voltage hermetic compressor motor design developed for chiller applications has shown recurrent insulation failures in certain stator end-turn regions. Initial investigations found discoloration of failed coil insulation and suggested that the stator coils over heated during operation at rated load. Thermal modeling was conducted to develop an understanding of the causes of the unacceptably high motor failure rate so that corrective actions could be taken for future motor designs. This paper presents thermal modeling efforts for predicting steady-state temperature distributions within the stator coil in the end-turn region under full-load electrical heating and a refrigerant cooling environment. Insulation thermal conductivity and coil surface convection heat transfer coefficient were identified as two critical heat transfer parameters which dictate the effectiveness of coil heat dissipation. Thermal analysis results have been correlated with measured temperature dependent insulation thermal conductivities and stator coil surface temperatures measured in motor cooling tests. The results of thermal evaluation indicate that the premature motor failures are likely caused by excessive conductor heating due to high operating current density in a non-uniform coolant distribution.Item Thermal Measurement and Prediction of an Air-Cooled Induction Motor(0000-00-00) Liu, H-P.; Werst, M.D.Active cooling is typically required for continuously operated electric motors to prevent rotors and stators from overheating. Various motor cooling designs have been developed in the past to meet the needs and constraints for different motor applications. This paper presents thermal measurement and prediction of an induction motor which is an integral part of a large energy storage generator. The induction motor was designed to be cooled by unidirectional airflow ventilated across the air gap between the rotor and the stator. Transient rotor and stator temperatures have been measured for the described induction motor in a 2.87-hr thermal test. The energy storage generator was held at a constant speed of 3,500 RPM during the test, and the heat generation included windage, bearing, and motor electrical losses. Transient 3-D motor rotor and stator thermal analyses were performed using thermal and airflow parameters obtained in the test. Comparisons between the predicted and measured temperatures indicate the 3-D motor thermal modeling can provide relatively accurate thermal predictions.