Showing papers on "Vehicle dynamics published in 1973"
TL;DR: In this paper, the authors summarized applicable theory and data from simulation experiments on the directional control of automobiles subjected to crosswind gust disturbances and demonstrated that driver/vehicle response properties can be modeled and measured for a class of important closed-loop driving tasks.
Abstract: This paper summarizes applicable theory and data from simulation experiments on the directional control of automobiles subjected to crosswind gust disturbances. Measured driver/vehicle describing functions for several subjects and replications are presented and interpreted. It is shown that the driver's steering outputs can be explained as functions of lateral position and heading, although alternate interpretations involving path-angle and path-rate feedbacks are considered. The results demonstrate that driver/vehicle response properties can be modeled and measured for a class of important closed-loop driving tasks. They provide further direct experimental verification of the applicability of driver/vehicle theory to situations where the driver obtains his information from a real-world visual simulation. /Author/
38 citations
Journal Article•
TL;DR: The same theory for the STEADY-STATE RESPONSE to STEERing InPUT of the SIMPLE LINEAR TWO-DEGREE of FREEDOM VEHICLE can be applied to more COMPLEX LINEAR systems.
Abstract: AN APPROXIMATE METHOD IS PRESENTED WHICH PRODUCES A HANDLING DIAGRAM USEFUL FOR THE STUDY OF STEADY-STATE TURNING BEHAVIOR AT DIFFERENT VALUES OF STEER ANGLE, PATH RADIUS AND SPEED. THREE SUCCESSIVE PARTS DISCUSS HANDLING DIAGRAMS OF SIMPLE SYSTEMS; STABILITY OF THE STEADY-STATE TURN, AND THEORY APPLIED TO MORE ELABORATE SYSTEMS. ESSENTIALLY THE SAME THEORY FOR THE STEADY-STATE RESPONSE TO STEERING INPUT OF THE SIMPLE LINEAR TWO-DEGREE OF FREEDOM VEHICLE CAN BE APPLIED TO MORE COMPLEX LINEAR SYSTEMS. THE ONLY REAL DIFFERENCE IS THAT NEWLY INTRODUCED EFFECTIVE SLIP ANGLES AND EFFECTIVE CORNERING STIFFNESS OF FRONT AND REAR AXLES WILL REPLACE THE REAL SLIP ANGLES AND CORNERING STIFFNESSES OF THE TIRE PAIRS. /DOT/
25 citations
01 Feb 1973
19 citations
TL;DR: In this article, the authors reviewed recent developments in the understanding of the lateral dynamics of railway vehicles with particular reference to the problems of dynamic stability, guidance and response to track features, focusing on the physical models used and the broad conclusions they lead to, rather than the engineering design that represents the practical application of the subject.
Abstract: Recent developments in the understanding of the lateral dynamics of railway vehicles are reviewed with particular reference to the problems of dynamic stability, guidance and response to track features The emphasis is placed on the physical models used and the broad conclusions they lead to, rather than the engineering design that represents the practical application of the subject
12 citations
TL;DR: A general purpose computer program for calculating the dynamic response of vehicles traveling over surface or evaluated guideways is described in this article, which is modular in design and is based on the finite element or building block method in which a complex dynamic system is made up of a number of components.
Abstract: A general purpose computer program for calculating the dynamic response of vehicles traveling over surface or evaluated guideways is described. The program has application to a broad class of transportatio n systems and hence eliminates the need for numerous specialized programs. The program is modular in design and is based on the finite element or building block method in which a complex dynamic system is made up of a number of components. The equations of motion for each of these components is known, and the program automatically combines the component equations to form equations of motion for the complete system. The equations of motion are then integrated numerically to give the response of the system to variables such as guideway roughness, span length, etc. Several output options are available and on-line printer plots or off-line CalComp plots of the response can be obtained. Addition building blocks can be easily added to.the program whenever desired. The program is written in PL/I language and has been used on the IBM 360/91 computer. The program has been used on a limited number of problems, several of which are included in this paper. GENERAL purpose computer program (APLDYN)1 has been written for the simulation of the dynamics associated with vehicles traveling over surface or elevated guideways with prescribed irregularities. The program has application to a broad class of transportation systems and hence eliminates the need for numerous specialized programs. It is based on the finite element method in which a complex system is made up of a number of discrete components. This technique is not new to the structural engineer, but it has seen limited application to dynamic problems associated with discrete moving masses. The APLDYN application of this finite element technique to moving vehicle problems is similar to, but more general than that used by Hunt 2 to determine the dynamic response of a flexible vehicle moving along a flexible supporting structure. Other simulations3 ~~ 5 although useful for studying the dynamic behavior of specific systems, have been limited in scope and versatility. Kaplan et al. 3 have developed a simulation for the vertical response of a single car or a two-car train traveling across an elevated guideway with no irregularities. The guideway flexibility provides the dynamic ex citation. McHenry and Deleys4 have written a simulation for the response of automobiles when encountering obstacles such as guard rails, railroad crossings and abutments. The simulation does not handle the more general class of vehicles, elevated guideways, and roadbed irregularities encountered in new transportation systems. Melpar has also developed a comprehensive computer program5 but this program is written specifically for a conventional railcar on a surface track. The Melpar program handles a multidegree-of -freedom system but is limited in the number of mass elements that can be simulated.
10 citations
01 Jan 1973
TL;DR: A survey of the research concerned with the dynamics of single, conventional railway vehicles is presented in this article, focusing on analytical research and experimental research performed in conjunction with analytical efforts, and the often conflicting objectives for railway vehicle suspension design and the research done to understand the design implications of these objectives are discussed.
Abstract: A survey of the research concerned with the dynamics of single, conventional railway vehicles is presented. Attention is concentrated on analytical research and experimental research performed in conjunction with analytical efforts. The often conflicting objectives for railway vehicle suspension design and the research done to understand the design implications of these objectives are discussed.
6 citations
TL;DR: In this article, the application of a proportional integral differential (PID) control scheme to the problem of regulating the longitudinal motion of vehicles traversing nonlevel terrain is presented, where a third-order representation of the vehicle dynamics is used, and a moving-cell controller is designed using pole placement techniques.
Abstract: The application of a proportional-integral-differential (PID) control scheme to the problem of regulating the longitudinal motion of vehicles traversing nonlevel terrain is presented. A third-order representation of the vehicle dynamics is used, and a moving-cell (fixed reference) controller is designed using pole placement techniques. Analog computer simulation results are presented.
3 citations
01 Jan 1973
TL;DR: In this article, the optimal estimation of the vehicle position with given erroneous range data has been studied in an Acoustic Transponder Navigation System (ATN) using a least square error criterion.
Abstract: In an Acoustic Transponder Navigation System the vehicle position is determined in relation to the transponders by the use of ranges to the transponders and the distances between the transponders. The vehicle position determined is usually inaccurate due to the timing error and the inaccuracy of the sound velocity assumed in obtaining the range data. This paper develops computational algorithms for the optimal estimation of the vehicle position with given erroneous range data. The development begins with the formulation of a least-squares error criterion. Computational algorithms are then developed to best estimate the vehicle position by minimizing the least-squares error criterion. For the moving vehicles, optimal filtering algorithms are developed which sequentially update the vehicle position based on the knowledge of the vehicle dynamics and the range measurements. Computational results for one illustrative example in the application of the optimal filtering algorithms are presented.
3 citations
01 May 1973
TL;DR: In this paper, a power control system that provides longitudinal control of vehicles by a unique method in which it distributes power to those vehicles is presented, where the vehicles are passive (control-wise) in that power modulation is accomplished by the vehicle's position within the traveling control section.
Abstract: SYNCHROTRAC is a power control system that provides longitudinal control of vehicles by a unique method in which it distributes power to those vehicles. The vehicles are passive (control-wise) in that power modulation is accomplished by the vehicle's position within the traveling control section. Therefore, no on-board power modulation or communication equipment is required. The SYNCHROTRAC system can be readily employed in a wide variety of transportation applications. It is adaptable to the closed-circuit moving sidewalk applications that require slow captive vehicles operating with small headways as well as to the independently routable dual-mode application that requires fast vehicles operating with small headways. The specific vehicle design can vary to suit a particular application requiring only that the motive drive be an induction motor providing the appropriate vehicle dynamic response, i.e., voltage and frequency versus torque.
01 Feb 1973
TL;DR: In this paper, an investigation was conducted to evaluate the lateral forces and moments produced on a vehicle with large, flat lateral faces when it is passing or being passed by a large vehicle in an adjacent traffic lane.
Abstract: This paper describes an investigation that was undertaken to evaluate the lateral forces and moments produced on a vehicle with large, flat lateral faces when it is passing or being passed by a large vehicle in an adjacent traffic lane. The forces and moments were determined from tests that were conducted in the University of Tennessee subsonic wind tunnel. They were, then, input to a computerized vehicle model to find the resulting dynamic response of the vehicle. These forces and moments were sufficiently strong to produce a significant lateral deviation from the desired path of the vehicle. Resulting from this investigation, several recommendations were made to improve highway safety. /Author/
01 Oct 1973
TL;DR: In this paper, a critical assessment of computer simulation programs to model the structural response of automobiles during vehicle impact is given relative to the simulation needs of NHTSA, where a variety of modeling concepts and degrees of sophistication have been employed.
Abstract: In recent years a number of investigators have developed computer simulation programs to model the structural response of automobiles during vehicle impact. A variety of modeling concepts and degrees of sophistication have been employed. In this report a critical assessment of these programs is given relative to the simulation needs of NHTSA.
01 Oct 1973
TL;DR: Using the simplified dynamics of a supersonic aircraft as an example, a procedure for synthesis of a digital control filter is presented and a good vehicle for the realization of appropriate control equations is the "frequency transformation".
Abstract: The application of digital onboard computers for flight control of high-performance aerospace vehicles is desirable, with respect to hardware effort and reliability, as well as operational flexibility. Up to now, digital computers have not been used for the control of short periodic angular oscillations. This task can be solved with the capability of digital computers now available. A good vehicle for the realization of appropriate control equations is the ?frequency transformation?. Using the simplified dynamics of a supersonic aircraft as an example, a procedure for synthesis of a digital control filter is presented. After a first evaluation in the s domain, the design is checked for validity in the frequency domain. If necessary, the original design is corrected appropriately.
01 Jan 1973
TL;DR: In this article, the authors describe the dynamic considerations in the design of long span (200 to 600 feet) cable-stayed guideways for tracked air cushion vehicles (TACV's).
Abstract: This paper describes the dynamic considerations in the design of long span (200 to 600 feet) cable-stayed guideways for tracked air cushion vehicles (TACV's). A design approach is described in which a cable-stayed guideway structure can be synthesized to simulate the behavior of a beam on elastic foundation. This result is achieved by the "cable'tuning" approach, in which the cable stays are selected to achieve an equivalent uniform elastic foundation. A tower configuration is then selected to minimize the effect of tower structural compliance, relative to the vertical deviation of the vehicle as it traverses the span. Therefore, the live load deflection of the trackway structure is manifested as a traveling wave which moves horizontally at the same speed as the vehicle. This approach satisfies the dynamic requirements for acceptable passenger ride comfort and minimal vehicle/guideway dynamic interaction.
01 Dec 1973
TL;DR: In this article, the effects of various antilock system configurations on the directional control of passenger cars are evaluated on straight and curved paths with high, medium, and low friction coefficient surfaces.
Abstract: The effects of various antilock system configurations on the directional control of passenger cars are documented. Tests were conducted on straight and curved paths with high, medium, and low friction coefficient surfaces. To isolate the effects of the antilock systems, one test vehicle was tested with the following antilock systems: no antilock; drive shaft controlled rear; select-low rear; select-low front and rear; independent front, select-low rear; four-wheel independent. Two additional vehicles of similar weight were tested with and without a drive shaft controlled rear antilock system to assess the effects of vehicle dynamics. Results suggest that the four-wheel independent configuration performs best from a safety standpoint and that vehicle dynamics affect performance of the antilock system. /NTIS/
01 Feb 1973
TL;DR: The behavioral applications of vehicle-dynamics simulation are described and modeling the dynamic properties and characteristics of the automobile and driving are emphasized.
Abstract: The behavioral applications of vehicle-dynamics simulation are described. Modeling the dynamic properties and characteristics of the automobile and driving are emphasized.
01 Jan 1973
01 Sep 1973
TL;DR: In this article, an analytical and experimental investigation on the stability and handling of articulated vehicles was conducted to develop stability criteria for tractor single-, double-, and triple-semitrailer vehicles during commonly encountered road and speed maneuvers subject to environmental influences.
Abstract: An analytical and experimental investigation on the stability and handling of articulated vehicles was conducted to develop stability criteria for tractor single-, double-, and triple-semitrailer vehicles during commonly encountered road and speed maneuvers subject to environmental influences. To this end, an experimentally validated digital simulation model, AVDS3, was further developed and validated. It was utilized to generate physical stability limits for articulated vehicles. During the investigation, the direct method of Lyapunov was employed to generate mathematical stability limits of cornering articulated vehicles. In addition, an effort was made to apply the concept of finite time stability to this problem. Portions of this document are not fully legible. /NTIS/