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Showing papers on "Vehicle dynamics published in 1970"


ReportDOI
01 Jun 1970
TL;DR: In this paper, a study of the correlation of pilot model parameters and closed-loop performance with pilot opinion of VTOL hover dynamics was conducted, and a new method of specifying hover dynamics followed naturally.
Abstract: : A study of the correlation of pilot model parameters and closed-loop performance with pilot opinion of VTOL hover dynamics was conducted. The encouraging results suggested a pilot-vehicle analysis method of predicting pilot model parameters, closed-loop pilot-vehicle performance with gust inputs, and pilot opinion ratings for a wide range of vehicle dynamics. This approach was, in turn, used to predict ratings for comparison with fixed base, moving base, and flight test results for VFR conditions. Again the results were promising, and a new method of specifying hover dynamics followed naturally. The new pilot-vehicle analysis concept, called the minimum pilot rating method, is discussed in terms of applications to other tasks, flying qualities specification, and control system design.

48 citations



Proceedings ArticleDOI
01 Feb 1970

13 citations



Proceedings ArticleDOI
01 Feb 1970

8 citations


Proceedings ArticleDOI
01 Feb 1970
TL;DR: In this article, the authors show that the post-collision motion is a PLANE MOTION, governed by Inertia and TIRE FRICTION, where the VEHICLES acquire new sets of VELOCITIES THROUGH an exchange of momentum.
Abstract: THE POSTCOLLISION MOTION STARTS IMMEDIATELY UPON COMPLETION OF A COLLISION IMPACT WHERE THE VEHICLES OBTAIN NEW SETS OF VELOCITIES THROUGH AN EXCHANGE OF MOMENTUM. SIMILITUDE WITH MODEL STUDY AND FULLSCALE AUTOMOBILE EXPERIMENTS INDICATE THAT THE POST-COLLISION TRAJECTORY IS ESSENTIALLY A PLANE MOTION, GOVERNED BY INERTIA AND TIRE FRICTION. TRAJECTORIES DEPEND ON MANY PARAMETERS (SUCH AS TIRE FRICTION COEFFICIENT, FRONT WHEEL STEERING ANGLE, VEHICLE GEOMETICS, AND WHETHER WHEELS ARE LOCKED OR FREE TO ROTATE) BUT NOT ON THE VEHICLE WEIGHT. THEORETICAL COMPUTATION OF TRAJECTORIES ARE COMPARED WITH EXPERIMENTS. /AUTHOR/

8 citations



Proceedings ArticleDOI
01 Feb 1970

7 citations


Journal ArticleDOI
TL;DR: The pilot model is applicable to the control of not only the helicopter, but all VTOL vehicles, and the reduction of higher-order inputs to zero permits applicability to vehicles with lower-order dynamics.
Abstract: A hierarchical model of a helicopter pilot is developed and mechanized by means of computer simulation. The basic element of the pilot model is a decision hierarchy which determines the multiloop closure and tracking characteristics of the man-vehicle system. Pilot model input is quantized and used by the hierarchy to determine the specific loop to be closed and the particular transfer function to apply to that loop. The pilot model and vehicle dynamics are implemented on a digital computer. Model validation is provided by comparison of tracking records obtained from this simulation of the vehicle with a human operator.Although developed for a vehicle with only the two lateral degrees of freedom, the pilot model is sufficiently general in form to allow its extension to six degrees of freedom. As a fourth-order system, it is applicable to the control of not only the helicopter, but all VTOL vehicles. The reduction of higher-order inputs to zero permits applicability to vehicles with lower-order dynamics. I...

5 citations


01 Jan 1970
TL;DR: In this article, the authors proposed a method for measuring vehicle behavior under long-itudial and late-algorithmic conditions, in which the VEHICLE is subject to longitudinal and lateral forces.
Abstract: THE NEED TO CONSIDER AUTOMOBILE DYNAMIC PROBLEMS, IN WHICH THE VEHICLE IS SUBJECT TO LONGITUDINAL AND LATERAL FORCES SIMULTANEOUSLY, IS OUTLINED. TETHERED TESTING IS PROPOSED AS A METHOD FOR MEASURING VEHICLE BEHAVIOR UNDER THESE CONDITIONS, AND UP TO THE MAXIMUM LATERAL FORCE THAT CAN BE OBTAINED. EQUIPMENT AND DATA ANALYSIS PROCEDURES ARE DESCRIBED. IT IS SHOWN THAT THE RATE OF CHANGE OF STEER ANGLE WITH LATERAL ACCELERATION AND THE RATE OF CHANGE OF STEER ANGLE WITH SLIP ANGLE ARE SUITABLE QUANTITIES FOR CHARACTERIZING VEHICLE STEADY STATE BEHAVIOR. RESULTS ARE PRESENTED IN TERMS OF THESE QUANTITIES TO ILLUSTRATE THE EFFECTS OF COMBINED CORNERING AND TRACTION FOR FRONT AND REAR WHEEL DRIVE VEHICLES. /HSL/

4 citations


Proceedings ArticleDOI
01 Feb 1970
TL;DR: In this article, a new approach is described in which CONVENTIONAL control system ANALYSIS TECHNIQUES are used to derive the TRANSFER FUNCTION RELATING STEER INPUT to VEHICLE LATER MOTION.
Abstract: A NEW PROCEDURE IS DESCRIBED IN WHICH CONVENTIONAL CONTROL SYSTEM ANALYSIS TECHNIQUES ARE USED TO DERIVE THE TRANSFER FUNCTION RELATING STEER INPUT TO VEHICLE LATERAL MOTION. THE INFLUENCE OF THE DRIVER'S LIMITED TORQUE CAPABILITIES ON THE STEERING SYSTEM INPUT IS INTRODUCED. THIS APPROACH PRODUCES SOMEWHAT DIFFERENT DESCRIPTIONS OF VEHICLE RESPONSE FROM THOSE OBTAINED IN THE PAST WHEN SUCH DESCRIPTIONS DID NOT INCLUDE THIS DRIVER INFLUENCE. SINCE THE RESULTING TRANSFER FUNCTION IS A UNIQUE ON THE ROAD DESCRIPTION OF VEHICLE DYNAMICS, REALISTIC VEHICLE MOTION RESPONSE TO ANY QUANTIFIABLE STEER INPUT CAN BE COMPUTED. /HSL/

ReportDOI
01 Feb 1970
TL;DR: In this paper, the mathematical equations of motion required to construct a hybrid model simulation of a vehicle operating on rigid terrain are presented, grouped roughly by vehicle components: sprung mass, unsprung mass, suspension, drive train/brakes, wheels and tires.
Abstract: : The report contains the mathematical equations of motion required to construct a hybrid model simulation of a vehicle operating on rigid terrain. They are grouped roughly by vehicle components: sprung mass, unsprung mass, suspension, drive train/brakes, wheels and tires. Equations representing both the double A-arm and the solid axle suspension system and two different tire models (one assuming the 'friction circle' and the other the friction ellipse concept of total tire force) are included.

DOI
01 Jan 1970
TL;DR: In this paper, the authors combine engine emissions maps with engine operating conditions as calculated by a vehicle simulation model to assess the pollutant unit emissions for road vehicles, using Windows on a PC microcomputer, taking into account: the vehicles characteristics (engine, transmission, mass, aerodynamics); various operating parameters, such as the vehicle load or the use of accessories (ligthing, air conditioning, etc.).
Abstract: To assess the pollutant unit emissions for road vehicles, we combine engine emissions maps with engine operating conditions as calculated by a vehicle simulation model. The SIMULCO software, using Windows on a PC microcomputer, takes into account: the vehicles characteristics (engine, transmission, mass, aerodynamics ...); various operating parameters, such as the vehicle load or the use of accessories (ligthing, air conditioning ...); the trips characteristics (road gradients and curves, speed limits, stops); and the drivers characteristics (throttle opening, engine revolution speeds ...). This model calculates instantaneous operating conditions, in particular the engine torque and speed, wich in turn enables the calculation of pollutant emissions (CC>2, CO, HC, NOx, particulate) and of fuel consumption. It offers three possibilities: firstly driver simulation, where operating conditions and the vehicle dynamics are dependent on driving practice; secondly the kinematic following, as the case of a driving cycle, where the vehicle dynamic is imposed; and thirdly the calculations at steady speed. Results show the great influence on fuel consumption and pollutant emissions of vehicle mass, vehicle speed, road gradient, air conditioning use ..., for different kinds of vehicles travelling on various trips or driving cycles.

Journal ArticleDOI
TL;DR: The goal of this program was to obtain highly detailed wind-tunnel measurements on research shapes and then use these data to carry out computer simulations of vehicle trajectories to eliminate various types of dynamic instabilities.
Abstract: During the past five years, the U.S. Naval Ordnance Laboratory, the Royal Aircraft Establishment, and the Australian Weapons Research Establishment have been engaged in a joint study of free-fall vehicle dynamics. The goal of this program was to obtain highly detailed wind-tunnel measurements on research shapes and then use these data to carry out computer simulations of vehicle trajectories. These simulations were compared with actual measurements obtained from a full-scale instrumented store in free flight. The program was also concerned with a wind-tunnel and free-flight investigation of novel stabilizers (tails) designed to eliminate various types of dynamic instabilities.

01 Jan 1970
TL;DR: This communication illustrates a simple technique for identifying the pilot/vehicle describing functions from routine flight test records and provides a straightforward method of analyzing and comparing the dynamics of closed-loop attitude control tasks from actual flight test operations.
Abstract: This communication illustrates a simple technique for identifying the pilot/vehicle describing functions from routine flight test records. This technique provides a straightforward method of analyzing and comparing the dynamics of closed-loop attitude control tasks from actual flight test operations. Some results from the Gemini and X-15 flight test records tend to confirm previous findings that the pilot tries to adjust his dynamics such that the combined pilot/vehicle describing function can be described by a simple crossover model.

Proceedings ArticleDOI
01 Feb 1970
TL;DR: In this paper, the authors discuss the problems of highway VEHICLE DYNAMIC RESPONSE and control in EMERGENCY BRAKING MANEUVERS and the applicability of automotive BRAKING control system for IMPROVING vehicle performance in these MANUVERS.
Abstract: PROBLEMS OF HIGHWAY VEHICLE DYNAMIC RESPONSE AND CONTROL IN EMERGENCY BRAKING MANEUVERS AND THE APPLICABILITY OF AUTOMATIC BRAKING CONTROL SYSTEMS FOR IMPROVING VEHICLE PERFORMANCE IN THESE MANEUVERS ARE DISCUSSED. IT IS SHOWN THAT AUTOMATIC BRAKING CONTROL SYSTEMS CAN IMPROVE VEHICLE RESPONSE AND HANDLING CHARACTERISTICS IN THE FOLLOWING AREAS: (1) STOPPING DISTANCE, (2) LATERAL STABILITY CHARACTERISTICS IN BRAKING MANEUVERS, AND (3) DIRECTIONAL CONTROL CHARACTERISTICS IN MANEUVERS WITH COMBINED BRAKING AND STEERING. THE METHOD OF APPROACH CONSISTS OF AN ASSESSMENT OF THE STATE-OF-THE-ART IN BREAKING CONTROL SYSTEMS; AN ANALYSIS OF THE EFFECT OF TIRE SLIP ON VEHICLE DYNAMIC RESPONSE; ESTABLISHMENT OF EFFECTIVENESS CRITERIA FOR THE EVALUATION OF THE DYNAMIC RESPONSE OF HIGHWAY VEHICLES IN EMERGENCY BRAKING MANEUVERS; AND HYBRID COMPUTER SIMULATION OF THE RESPONSE OF AN AUTOMOBILE EQUIPPED WITH AUTOMATIC BRAKING CONTROL. CONCLUSIONS AND RECOMMENDATIONS EMPHASIZE THE POTENTIAL BENEFITS TO HIGHWAY SAFETY TO BE GAINED WITH IMPROVEMENTS IN VEHICLE RESPONSE IN ACCIDENT AVOIDANCE MANEUVERS, AND IN PARTICULAR, THE APPLICATIONS OF AUTOMATIC CONTROL SYSTEMS IN THIS AREA. /AUTHOR/