Naohiro Yuhara

An Analytical Approach to the Prediction of Handling Qualities of Vehicles With Advanced Steering Control System Using Multi-Input Driver Model

This paper describes an analytical approach to predict the subjective rating on handling qualities of actively controlled vehicles. The approach was applied to the evaluation on handling qualities of 4 wheel steering vehicles. The validity of the approach is confirmed by comparison of the predicted results with test data. The essential feature of the approach is to use an objective function that takes into account three principal factors, i.e., the task performance, the drivers mental workload, and his or her physical workload, to predict analytically the subjective ratings. The findings indicate that the predicted rating directly corresponds to the drivers subjective ratings obtained through the proving ground test with a good correlation.

Two Degree of Freedom/H∞ Controller Synthesis for Active Four Wheel Steering Vehicles

SUMMARY This paper proposes an active front and rear wheel steering control system that simultaneously achieves both lateral acceleration and yaw rate responses always desirable regardless of changes in vehicle dynamics. First, this paper describes a method to accurately estimate physical parameters in the four wheel steering vehicle model, including the dynamics of a steering actuator, by applying the maximum likelihood estimation method. Next, the structure of the proposed front and rear steering control system is described. This control system has for its purpose to coincide both the lateral acceleration and yaw rate responses of the vehicle with the responses of the respective desirable reference models, as well as to make it a robust system against changes in vehicle dynamics and external disturbances. To achieve both objectives, a two-degree-of-freedom control system theory is employed. Then the paper shows the viability of the proposed steering control system through computer simulations. Finally, ...

Advanced Steering System Adaptable to Lateral Control Task and Driver's Intention

This paper proposes an advanced steering system that adaptively varies the static gain and dynamics of the steering system. The steering system gain is adjusted, depending on whether the driver is in an aggressive or leisurely driving mood. The steering system dynamics is so designed that the command mode of the steering system will be either a rate-command or an attitude-command according to the lateral control task performed by the driver. The recognition system for lateral control tasks, a lane-following or lane-change task is proposed. The findings of simulator tests indicate proposed advanced steering system would remarkably improve the vehicle handling qualities.

TWO-DEGREE-OF-FREEDOM HYDRAULIC PRESSURE CONTROLLER DESIGN FOR DIRECT YAW MOMENT CONTROL SYSTEM

Abstract This paper describes the controller design scheme for the hydraulic system in Direct Yaw Moment Control (DYC) System for a front-engine front drive vehicle. Regardless of the hydraulic systems characteristics changes over a wide range of operational conditions, the hydraulic system is required to achieve the desirable speed of response and stability. This paper, therefore, proposes a two-degree-of-freedom hydraulic control system consisting of reduced-order controllers to satisfy these requirements. From the results of proving ground tests, it is confirmed that the proposed control system satisfies the requirements imposed on the hydraulic system for a DYC system.

AN ADVANCED STEERING SYSTEM WITH ACTIVE KINESTHETIC FEEDBACK FOR HANDLING QUALITIES IMPROVEMENT

SUMMARY Advanced Steering System with artificial steering wheel torque-active kinesthetic information feedback for improving handling qualities is discussed. Fundamentally the structure of the system may be considered to another form of model following control. In this system, a driver always remains in the control loop and receives steering control information which give him/her a direct hint to steer a steering wheel. This system works as a stability and control augmentation system of the vehicle to improve the vehicle handling qualities both in compensatory and pursuit control task, and is expected to reduce drivers workload. Effects of this system are analyzed in terms of man-machine system characteristics. Identification of driver dynamics was carried out to find why such improvement could be achieved. Availability of the proposed system is verified by analysis, simulator and proving ground tests.

Development of predicting evaluation platform of advanced driver safety assist systems using integrated virtual traffic environments

Advanced driver safety assist systems are expected as the useful tools to decrease the traffic accidents, and are under developments in many automobile manufacturers. From the political points of view, predicting the effects of each advanced driver safety assist system on driver-vehicle safety improvement quantitatively, in the early stage of the system development activities, is important to define the priority of development of the systems. Also the prediction method will give further technical knowledge of new driver assist system concepts to the automobile manufacturers. This paper proposes the integrated evaluation methodology of advanced safety driver assist systems. Proposed evaluation platform is composed by integrated virtual traffic environments, including micro integrated driver models, macro car traffic simulation models, networked driving simulators and probe cars.