scispace - formally typeset
Search or ask a question

Showing papers on "Vehicle dynamics published in 1980"


Journal ArticleDOI
TL;DR: In this paper, a compensatory tracking model of the human pilot is presented, which attempts to provide a more realistic representation of human signal processing structure than that which is exhibited by pilot models currently in use.
Abstract: A compensatory tracking model of the human pilot is offered, which attempts to provide a more realistic representation of the human's signal processing structure than that which is exhibited by pilot models currently in use. Two features of the model distinguish it from other representations of the human pilot. First, proprioceptive information from the control stick or manipulator constitutes one of the major feedback paths in the model, providing feedback of vehicle output rate due to control activity. Implicit in this feedback loop is a model of the vehicle dynamics which is valid in and beyond the region of crossover. Second, error rate information is continuously derived and independently but intermittently controlled. An output-injected remnant model is offered and qualitatively justified on the basis of providing a measure of the effect of inaccuracies such as time variations in the pilot's internal model of the controlled-element dynamics. The data from experimental tracking tasks involving five different controlled-element dynamics and one nonideal viewing condition were matched with model-generated describing functions and remnant power spectral densities.

81 citations


01 Dec 1980
TL;DR: In this article, the tunnel display with superimposed predictor/director symbols was shown to be a very successful combination, which outperformed the other two displays in all three experiments, and a prediction time of 4 to 7 seconds was found to optimize trajectory tracking for given vehicle dynamics and flight condition.
Abstract: The display was evaluated by monitoring pilot performance in a fixed base simulator with the vehicle dynamics of a CH-47 tandem rotor helicopter. Superposition of the predicted future vehicle position on the tunnel image was also investigated to determine whether, and to what extent, it contributes to better system performance (the best predicted future vehicle position was sought). Three types of simulator experiments were conducted: following a desired trajectory in the presence of disturbances; entering the trajectory from a random position, outside the trajectory; detecting and correcting failures in automatic flight. The tunnel display with superimposed predictor/director symbols was shown to be a very successful combination, which outperformed the other two displays in all three experiments. A prediction time of 4 to 7 sec. was found to optimize trajectory tracking for the given vehicle dynamics and flight condition. Pilot acceptance of the tunnel plus predictor/director display was found to be favorable and the time the pilot needed for familiarization with the display was found to be relatively short.

39 citations


Patent
Lael B. Taplin1
30 Jun 1980
TL;DR: In this paper, an open loop adaptive control system for improving the driveability of a vehicle having at least one air supply modulator such as a throttle is presented, where the correction signal when added to the operator commanded signal input to the air supply is such as to cancel the speed and pressure variability of the engine and vehicle dynamics and substitute for these dynamics determinable vehicle control dynamics therein improving the vehicle by establishing uniform performance.
Abstract: An open loop adaptive control system for improving the driveability of a vehicle having at least one air supply modulator such as a throttle. The control system generating a correction signal supplied to the air supply modulator wherein the correction signal when added to the operator commanded signal input to the air supply modulator is such as to cancel the speed and pressure variability of the engine and vehicle dynamics and substitute for these dynamics determinable vehicle control dynamics therein improving the driveability of the vehicle by establishing uniform performance.

34 citations



Journal ArticleDOI
TL;DR: In this paper, a variable characteristic car (VCC) has been developed at Melbourne University for driverlvehicle handling research, which has facilities for varying both its fixed control and free control dynamic characteristics over wide ranges.
Abstract: SUMMARY A variable characteristic car (VCC) has been developed at Melbourne University for driverlvehicle handling research. The vehicle is unusual in that it has facilities for varying both its fixed control and free control dynamic characteristics over wide ranges. In this paper the servo systems used to effect these changes are described. The calibration methods used to relate the vehicle response characteristics to the variable servo settings are detailed. Sample calibration results are given for the fixed control parameters steering ratio, yaw response time and stability factor. Calibration of the free control parameters is also described and results are given for the steering torque gradient, and the time-to-peak and percentage overshoot of the steering wheel motion in response to a step input of torque.

5 citations


Journal ArticleDOI
TL;DR: In this paper, a modified mathematical model of a large capacity railroad freight vehicle is presented to describe the bounce, sway and rocking modes of the system and also to account for most of the vehicle nonlinearity effects.
Abstract: A modified mathematical model of a large capacity railroad freight vehicle is presented. The model for this investigation is constructed in such a way to describe the bounce, sway and rocking modes of the system and also to account for most of the vehicle nonlinearity effects. Equations of motion of the six degree of freedom nonlinear model are derived assuming that the excitations from the track in vertical and lateral directions are purely periodic in the form of a rectified sine wave. The solution for the time and frequency responses on digital computer are compared with available measured data to investigate the model accuracy. Multivariable optimization techniques are employed to find the optimum suspension parameters that minimizes the maximum rocking response over the frequency range of interest. The optimum parameters are presented in different forms either for the existing or for stabilized vehicle configuration.

3 citations


Journal Article
TL;DR: In this paper, the body/truck configuration of a magnetically levitated flexible vehicle is modeled with the carbody as a uniform beam having free ends, and it is concluded that such a two-truck vehicle with secondary suspensions at two points on each side is most desirable when internal damping and bending stiffness of the car body cannot be increased for other reasons.
Abstract: The body/truck configuration of a magnetically levitated flexible vehicle is modeled with the carbody as a uniform beam having free ends. It is concluded that such a two-truck vehicle with secondary suspensions at two points on each side is most desirable when internal damping and bending stiffness of the carbody cannot be increased for other reasons.

2 citations


Dissertation
01 Jan 1980
TL;DR: Thesis (Ph.D.) as discussed by the authors, Mass. Institute of Technology, Dept. of Mechanical Engineering, 1980, Boston, Massachusetts, United States of America, USA, USA.
Abstract: Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1980.

2 citations


Journal Article
TL;DR: In this article, an analytical study of the dynamic behavior of a tractor-semitrailer vehicle is presented, showing system eigenvalues, power spectral densities and root mean square values of the linear and angular accelerations and displacements.
Abstract: The work describes an analytical study of the dynamic behaviour of a tractor-semitrailer vehicle. A digital computer simulation was used to describe the longitudinal, vertical, and pitching motions of the vehicle travelling over a stationary random road surface. A man-seat model was also incorporated into the simulation. Vehicle response to road irregularities has been studied by assuming two different roads for loaded and unloaded cases. Numerical results are presented for vehicle, showing system eigenvalues, power spectral densities and root mean square values of the linear and angular accelerations and displacements. Vehicle acceleration response is compared with the iso riding comfort standard. All results for the loaded and unloaded cases and for smooth and rough roads indicated that an uncomfortable ride would result from vehicle response.(a) (TRRL)

1 citations


01 Jan 1980
TL;DR: In this paper, the authors present an analysis of the various components of the motorcycle-rider-road system in the analysis of motorcycle suspension comfort and performance, and illustrative numerical examples of each approach are presented.
Abstract: Modeling of the various components of the motorcycle-rider-road system in the analysis of motorcycle suspension comfort and performance is described. Analytical techniques used in suspension design are reviewed, and illustrative numerical examples of each approach are presented. The transient response is based on an extensive numerical simulation program, which is highly detailed and models nonlinear suspension elements, travel stops, wheel liftoff, tire-rim bottoming, and large displacements. The sinusoidal response model is based on a six degree-of-freedom vibrational model which is treated through eigenvalue techniques. The high amount of damping present results in complex mode shapes which are most easily visualized by a dynamic visual image through computer graphics. This is especially important due to the phase shift between front and rear response. The random response analysis uses road power spectral density functions and mode shapes to determine random vehicle response and to estimate the amount of suspension travel required. Proper treatment of the excitation phase shift between front and rear wheels is vital in this method. Ride quality performance criteria are discussed in general and in the context of the numerical examples; the criteria relate to both rider comfort and vehicle control. The use of microprocessors, minicomputer systems, and computer graphics in motorcycle design is mentioned, and areas requiring further research are indicated.

1 citations