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This work develops a stochastic form of a human driver model which can be used for simulating vehicle guidance and control. The human motor-control function is complex and can be affected by factors such as driver's training and experience, fatigue, road conditions, and attention. The variations in these effects become more pronounced in hazardous driving conditions such as in snow and ice. One example of such driving conditions is snow removal operation in highway maintenance, where the use of a stochastic driver model seems to be more desirable. This work evaluates and extends existing models of a human driver including stochastic or statistical considerations related to differences in drivers' experiences and their conditions as well as variations in the effect of disturbances such as plowing forces. The aim is to develop a simulation environment that can be used in design and evaluation of driver assistance systems for snow removal operation in an Intelligent Transportation System environment. [DOI: 10.1115/1.2098927]

The performance of an automatic steering system based on an absolute positioning global positioning system (GPS) and a magnetic marker reference system during emergency situations is examined in this paper, as it is a vital safety issue in highway automation. Robust control technique in the form of parameter space approach in an invariance plane is utilized for lateral controller design based on a higher order nonlinear vehicle model. In addition, the control system incorporates an exponential smoothing algorithm based on road curvature preview for vehicle-handling enhancement. The proposed estimation and control system is shown, in computer simulations, to be effective in handling vehicle emergency situations. Index Terms--Gain scheduling, invariance plane, nonlinear vehicle model, parameter space approach, robust control, steering control.

Heavy vehicles play an economically important role in the transportation process, and their numbers have been increasing for several decades. The active safety of the highway system is an important consideration in the design of a heavy vehicle combination. In this paper, the handling characteristics of a 5-axle tractor-semitrailer is examined and used to test for the desired features of the vehicle's handling and stability. Using these results the optimal control criterion is derived for the vehicle. Four different control strategies are examined by using the Linear Quadratic Regulator (LQR) approach. These are, active steering of the rear wheels of the tractor; active steering of the wheels of the trailer; active torque control in the fifth-wheel joint; and active yaw torque acting on the tractor. These controllers are designed and examined using a simplified linear vehicle model. In addition to discussing the above-mentioned approaches, this paper discusses a method of modifying the slip angles at the tractor's rear (driven) axles, however the yaw torque at the tractor cg also can be controlled using what is called 'unilateral braking.' As well, the replacement of the active torque control at the fifth wheel joint, by a control strategy based on the usage of controllable dampers at the fifth-wheel joint, will also be examined. In this case, a nonlinear mathematical model of the vehicle is used and a modified control strategy called the RLQR/[H.sub.[infinity]] approach is used to ensure the vehicle's performance in the presence of parametric uncertainties. The examination of these control strategies is conducted by using a sophisticated non-linear vehicle model, and the influence of these control strategies on the vehicle's directional and roll stability during severe path-follow lane-change manoeuvre is discussed.

A control theoretic model of driver steering control behavior is presented. The resulting model is shown capable of producing driver/vehicle steering responses which compare favorably with those obtained from driver simulation. The model is simple enough to be used by engineers who may not be manual control specialists. The model contains both preview and compensatory steering dynamics. An analytical technique for vehicle handling qualities assessment is briefly discussed. Driver/vehicle responses from two driving tasks evaluated in a driver simulator are used to evaluate the overall validity of the driver/vehicle model. Finally, the model is exercised in predictive fashion in the computer simulation of a lane keeping task on a curving roadway where the simulated vehicle possessed one of three different steering systems: a conventional two-wheel steering system and a pair of four-wheel steering systems.

Byline: Zhang Junyuan, Hua Wei, Huang Bai, Lin Yi A mathematical occupant restraint model of a PR China-made mini-bus was established by using MADYMO software. The validity of the MADYMO model was evaluated against the head and chest responses from a crash test performed in accordance with the Chinese frontal impact regulation - CMVDR294. In this paper, the collapse load, stroke distance and mount angle of an energy absorbing steering system (EASS) were analysed and optimised in order to reduce the head and chest injury values of the occupant. Furthermore, the effectiveness of the EASS was analysed at different impact velocities. Robustness of the design with different configurations was also investigated using stochastic simulation.

Byline: F. Borrelli, P. Falcone, T. Keviczky, J. Asgari, D. Hrovat In this paper, a novel approach to autonomous steering systems is presented. A model predictive control (MPC) scheme is designed in order to stabilise a vehicle along a desired path while fulfilling its physical constraints. Simulation results show the benefits of the systematic control methodology used. In particular we show how very effective steering manoeuvres are obtained as a result of the MPC feedback policy. Moreover, we highlight the trade off between the vehicle speed and the required preview on the desired path in order to stabilise the vehicle. The paper concludes with highlights on future research and on the necessary steps for experimental validation of the approach.

Byline: S. Rakheja, J.A. Romero, A. Lozano, P.J. Liu, A.K.W. Ahmed In this paper, a comprehensive three-dimensional heavy vehicle model is developed to investigate the effectiveness of an open-loop roll instability control. The steering system compliance, roll steer, bump steer, Ackerman steer and wrap steer are incorporated in the vehicle model, along with a comprehensive tyre model and ABS algorithm. Time delays due to a driver's reaction and the transportation lag of the braking system are characterised by a variable called the reaction delay. The rollover indicators in terms of roll safety factor, tractor and trailer lateral accelerations and roll angles, and the rearmost axle roll angle are investigated for their effectiveness for open-loop roll stability control in various cornering and evasive manoeuvres, road conditions, braking efforts, and different reaction delays.

Byline: C.O. Nwagboso, X. Ouyang, C. Morgan An artificial neural network controller is developed for steer-by-wire of an intelligent vehicle. Prior to development of the control systems, the non-linear model of the steer-by-wire steering systems was developed. This was shown to be necessary to appreciate and understand the modelling difficulties and complexities inherent in modelling such steering systems. These difficulties and complexities were also shown to underpin the benefits and efficacy of neural-network control techniques for steer-by-wire system. By considering the non-linearity of steer-by-wire systems, a neural-network model reference adaptive control technique was used and this was integrated into the control of the steer-by-wire system test rig. The results of an extensive simulation and experimental study show that the non-linear dynamics of the steer-by-wire system have been well compensated by the adaptive compensator integrated as part of the controller.

To improve the efficiency of images presented in low-cost vehicle simulators, the virtual viewing direction (i.e., the direction in which the image is rendered) can be head-slaved, the display can […]