Tracked Air Cushion Vehicle Research Articles

Vibration control of superconducting electro-dynamic suspension train with electromagnetic and sky-hook damping methods

The superconducting electrodynamic suspension (EDS) train, which has reached a manned speed of 603 km/h in 2015, and is therefore regarded as one of the most attractive technologies for the higher speed train. In the superconducting EDS train, the discrete layout of ground null-flux coils causes the additional electromagnetic ripples towards the bogies, making the vibration control more essential to ensure the running performance. In this work, a fourteen-degree-of-freedom dynamics model of superconducting EDS train, was established to explore the effective strategy for vibration reduction. This model uses the time domain wave of track irregularity spectrum as the input of vehicle system. MATLAB/Simulink and "Zhai’s method" are both adopted to solve the vehicle dynamic model and validate the model. Using these models, the effectiveness of the proportional force and maximum force for the primary suspension was examined. The results show that the maximum force strategy has advantage over the proportional force strategy in terms of energy consumption and vibration sensitiveness. However, the electromagnetic damping control can only suppress the vibration of bogie. To achieve an overall vibration control, the "ON-OFF" sky-hook damping was further introduced to the secondary suspension to suppress the vibration of car body. We find that, the control effect is preferable with the damping value being between 5 kN·s/m and 10 kN·s/m. Therefore, the cooperative control, considering both the primary and secondary suspensions, is necessary to meet the Urban Tracked Aircushion Vehicle Standard and provide theoretical supports for the suspension design of superconducting EDS train.

An experimental comparison between semi–active and passive suspensions for air–cushion vehicles

An experimental heave made model of a tracked air–cushion vehicle incorporating on–off semi–active (SA) damper suspension is described. Preliminary tests are conducted to assess the SA pneumatic damper characteristics. For identical sinusoidal ground inputs, the totally passive and on–off SA damping schemes are compared in terms of sprung mass vibration isolation properties. It is shown that the semi–active suspension offers significant advantages over the corresponding passive suspensions, while at the same time requiring only a small amount of control energy. Although the performance of the pneumatic SA device is judged to be adequate for the case under investigation, it is concluded that, for more demanding applications, requiring higher controller speeds of response, an hydraulic SA implementation will probably have to be used.

Whitford Coating helps keep revolutionary magnetic "hover train" on track

Whitford Coating helps keep revolutionary magnetic "hover train" on track

Maglev Vehicle/Guideway Vertical Random Response and Ride Quality

Summary The research and development (R & D) of maglev technology had made a great progress in China since the early 1980s. Especially, a 35 km-long Shanghai high-speed maglev railway employing the German Transrapid system began to be constructed on March 1, 2001. Based on the Transrapid system, the paper develops a 10-degree-of-freedom model of maglev vehicle running over three types of guideways with constant speed. Random guideway irregularities are discussed and taken into account for simulation of the vehicle response and for evaluation of the ride comfort. Using the direct time integration method and the discrete fast Fourier transform (DFFT), random responses of the maglev vehicle-guideway systems are obtained and analyzed. Numerical results show that the resonant frequency of car body acceleration response is 0.5–1 Hz, and there is a 2.2 Hz periodic vibration due to the periodic configuration of rigid piers when the maglev vehicle travels over the elevated-beam guideway. The car body acceleration power spectral density (PSD) curves meet well the ride quality criterion of the urban tracked aircushion vehicle (UTACV) and the maximum acceleration of car body is less than 0.05 g. Moreover, the Sperling ride index values are less than 2.5 as long as the operational speed is less than 450 km/h. It is concluded that the maglev vehicle ride quality is quite well.

The Prediction of Passenger Riding Comfort From Acceleration Data

Various methods for evaluating ride quality in automobiles are investigated by means of a field study involving two different automobiles, seventy-eight different passengers, and eighteen different raodway sections. Passenger rating panels were used to obtain subjective evaluation of the various rides, and measured vibration spectra were examined on the basis of various frequency weighting techniques to determine their ability to predict the subjective ratings. Included in the evaluation criteria considered are weighting functions derived from the ISO (International Standards Organization) Standard, the UTACV (Urban Tracked Air Cushion Vehicle) Specification, and the Absorbed Power method of Lee and Pradko. Excellent correlation was found to exist between the subjective ride ratings and simple root mean square acceleration measurements at either the vehicle floorboard or the passenger/seat interface. Equations are presented to predict the subjective ride rating from measured vibration spectra.

On Using the ISO Standard To Evaluate the Ride Quality of Broad-Band Vibration Spectra in Transportation Vehicles

The International Standards Organization “Guide for the Evaluation of Human Exposure to Whole-Body Vibrations”, ISO 2631, is converted to a form usable for direct comparison with vibration data represented in power spectral density form. Comparisons are made between the ISO standard, the Urban Tracked Air Cushion Vehicle (UTACV) specification, and measured vibrations at the floorboard and seat of an automobile over smooth and rough roads. The data indicate that the ISO standard is less restrictive than the UTACV specification, and generally not restrictive enough to indicate the roughness of an automobile ride on a rough country road.

Heave Mode Dynamics of a Tracked Air Cushion Vehicle With Semiactive Airbag Secondary Suspension

Bond graph modeling techniques are used to develop a fully nonlinear heave mode model of a tracked air cushion vehicle incorporating a semiactive airbag secondary suspension. The governing state space equations were simulated for various deterministic guideway inputs and comparisons were made with the exact solution of the linearized equations. An experimental test stand is described which provides experimental corroboration of the mathematical models for the case of totally passive secondary suspension elements. Theoretical results are presented which demonstrate the superior vehicle ride characteristics with respect to passenger-guideway isolation provided by the combination of soft airbag springs and semiactive dampers.

Simple active aerodynamic suspension systems for high-speed ground vehicles

The feasibility of using active aerodynamic surfaces to improve the vertical ride quality of a tracked air cushion vehicle is investigated analytically with a six-degree-of-freedom linear model. Two aerodynamic fins actively control the pitch and plunge steady-state acceleration response of the passenger compartment to harmonic guideway excitations. For speeds of 200 and 300 mph, the choice of simple acceleration feedback signals sensed at the passenger compartment e.g. results in an acceptable ride quality. This is attained by practicable angles of attack and reasonable torques for the aerodynamic surfaces.

The case of the cancelled hovertrain

The case of the cancelled hovertrain

Reduction of TACV Power Requirements by Multiple-Stage Air Cushions

This paper shows that the power required for levitation for tracked air cushion vehicles can be significantly reduced by the use of multiple stage air cushions. A mathematical model for these air cushions is developed, and the air cushion pressures obtained from the model are compared with experimental pressures. It is shown that one of the most significant features of multiple stage air cushions is their inherent roll stability as opposed to an inherent instability for conventional air cushion designs. This inherent roll stability allows a significant reduction in the power required for levitation for tracked air cushion vehicles.

Tracked Air Cushion Vehicle Suspension Models: Analysis and Comparison

ABSTRACT In this paper several dynamical models of fluid suspensions for tracked air cushion vehicles are analyzed and compared. Specifically, the models considered conform to: a fifth-order linear suspension, a nonlinear configuration with a constant supply pressure, a nonlinear model with compressor characteristics, and a sixth-order nonlinear model with a supply duct connecting the compressor to the cushion chamber. Nonlinearities included in the analysis are the flexible-skirted cushion capacitance, cushion entrance and exit orifice restrictions, feeding system duct fluid capacitance, and compressor pressure-flow characteristics. Temporal responses are obtained for guideway and external force inputs. Back flow conditions under which the supply compressor can stall are examined. It is shown that the general behavior resulting from linear analysis is in many respects similar to that obtained from the nonlinear analysis. Thus, a linear model could provide a good initial basis for a preliminary design and...

Design Loadings and Structural Considerations for Tracked Air Cushion Research Vehicle

Simple analyses of vehicle responses to operating conditions are used as the basis for determining the types of loading significant for structural design of the Tracked Air Cushion Research Vehicle (TACRV). A brief development is given for the methods used to determine the magnitude of cushion applied loads along with the internal reactions and load paths associated with the several suspension configurations. Although the choice of materials and conservative design safety factors tend to preclude fatigue problems for the test vehicle, a brief analysis is given to indicate some potential fatiguecritical areas in tracked air cushion vehicle (TACV) prototypes designed to higher stress levels.

Inquiry Continues into Hovertrain's Demise

Inquiry Continues into Hovertrain's Demise

Hovertrain runs out of steam

Hovertrain runs out of steam

Guideway Camber and Three-Stage Passive Suspension for Improved Tracked Air Cushion Vehicle Ride Quality: Part II of a Parametric Study

Two means of providing a high quality air cushion ride at high speed using simple passive suspension systems are investigated. The inclusion of the proper amount of camber in guideway beams is shown to greatly reduce both low and high speed heave accelerations. A three-stage passively suspended vehicle including two degrees of pitching motion is shown to eliminate the high speed peak in accelerations present with two-stage vehicles. The effects of secondary and tertiary damping, of the vehicle to span length ratio, and of guideway camber on the ride quality of this vehicle are investigated. Coupled with cambered guideway beams, the three-stage passive suspension system appears to be an attractive alternative to active suspension systems.

Dynamic Interactions of High Speed Tracked Air Cushion Vehicles With Their Guideways: Part I of a Parametric Study

The vehicle-guideway system is modeled as an arbitrary number of lumped, doubly-sprung vehicle mass systems traveling in tandem along simple supported beams. The vehicle load is transmitted to the guideway as a time-varying uniform pressure compatible with vehicle motion. Effects of the dimensionless system parameters on vehicle heave acceleration, and guideway deflections and bending moments at high vehicle speeds are evaluated. Results for a vehicle which includes pitching motion compare favorably with those for a vehicle without pitch where the front and rear masses are uncoupled. By proper choice of parameters, passenger compartment heave accelerations can be minimized, although to keep this acceleration below 0.05g for vehicles traveling 100–300 mph requires systems with low vehicle to beam mass and frequency ratios as well as low vehicle lower to upper mass ratios. The benefits of distributed air cushion pressure to vehicle and guideway design are shown. Also, if the ratio of lower to upper vehicle mass is low, a constant moving pressure conservatively predicts the guideway response.

35. Data acquisition for a tracked air cushion vehicle: A. L. Niblett.Hovering Craft and Hydrofoil2 (6), 8–11 (1973).

35. Data acquisition for a tracked air cushion vehicle: A. L. Niblett.Hovering Craft and Hydrofoil2 (6), 8–11 (1973).

Total In-Flight Simulator (TIFS)-A New Aircraft Design Tool

2 Miller, T. J., Vehicle-Guideway Interaction Drag, Boeing Memo 2-1701TD172, Jan. 1972, Boeing Co., Seattle, Wash. 3 Grunwald, K. J., Aerodynamic Characteristics of Vehicle Bodies at Crosswind Conditions in Ground Proximity, TN D-5935, Aug. 1970, NASA. 4 Work Statement for Design and Construction of a Air Cushion Vehicle for Access to the Los Angeles International Airport, Sept. 23, 1970, City of Los Angeles, Dept. of Airports, Los Angeles, Calif. 5 Richardson, H. H., Captain, K. M., and Ribich, W. A., of Simple Air-Supported Vehicles Operating Over Irregular Guideways, MIT Report DSR 76110-4, June 1967, MIT, Cambridge, Mass., P. 173-655. 6 Press, H. and Tukey, J. W., Power Spectral Methods of Analysis and Their Application to Problems in Airplane Dynamics, Agard Flight Test Manual, Volume IV, Part 4-c, Bell Telephone Laboratories Monograph 2606, 1959. 7 HSGT System Engineering Air Cushion Vehicles, Contract No. C-353-66(NEG), Dec. 1969, TRW Systems Group, Washington, D.C. 8 Erickson, J. E., Secondary Suspension Requirements for TACV, Boeing Structural Dynamics Lab. Report 481, Feb. 1971, Boeing Co., Seattle, Wash. 9 Lee, R. and Pulgrano, L., Designing for Ride Quality in a High Speed Air Cushion AIAA Paper 71-385, Anaheim, Calif., 1971. 10 Design and Testing of Advanced Air Cushion Pad Configurations for Air Cushion Vehicles, Boeing Document D180-10581-1, Dec. 1970, Boeing Co., Seattle, Wash. 11 Biggers, S. B. and Wilson, J. E., Dynamic Interactions of High Speed Air Cushion Vehicles with Their Guideways— A Parametric Study, AIAA Paper 71-386, Anaheim, Calif., 1971. 12 Bliss, D. S., The Evolution of Air Cushion Vehicles, Hovering Craft and Hydrofoil, Aug. and Sept. 1970, Vol. 9, Nos. 11 and 12, pp. 17-47, 6-38. 13 Tracked Air Cushion Research Vehicle, Vol. I, Research Vehicle Preliminary Design, PSR ST4, Grumman Aircraft Engineering Corp., Bethpage, N.Y., March 1969. 14 Transit Expressway Report, MPC Corp., Pittsburgh, Pa., 1967.

Magnetic Levitation: Tomorrow's Transportation

At speeds above 200 mph, conventional means of suspending high speed ground vehicles lose their reliability. For this reason alternative, noncontact means of suspending and guiding vehicles at speeds up to or in excess of 300 mph have been sought. Two types of noncontact suspensions — the tracked air cushion vehicle and the magnetic levitation vehicle — are particularly attractive because of their capability for operation at high speeds of 300 mph or more. This report describes a proposed magnetic levitation system that can lift streamlined vehicles as high as a foot off aluminum guideways as they operate between urban centers, providing a safe, smooth ride that is quiet and pollution free.Frank Chilton and Howard T. Coffey, senior physicists, and L. O. Hoppie, physicist, are members of the applied physics laboratory of the Stanford Research Institute.

Noise Sources and Noise Abatement Potential for the Tracked Air Cushion Vehicle (TACV)

The tracked air cushion vehicle (TACV), currently being studied as a means of providing high-speed ground transportation, has some unique noise control problems not previously encountered in ground transportation systems. This study surveys the TACV noise sources and abatement potential of each source in light of the proposed criteria for sideline noise. Among the sources considered are the compressor, linear induction motor, current collector, and aerodynamic sources including the air cushion. Data from tests on the French TACV are presented and interpreted in terms of projections for the American TACV. [This study was supported by the Department of Transportation, Transportation Systems Center, Cambridge, Massachusetts, under contract.]