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It is intended in this study to use the in-wheel electric motors for the traction of the micro electric vehicle as the actuator for the steer-by-wire as well. Both right and left front suspensions of the front wheel drive electric vehicle have some large enough kingpin offsets in lateral direction and once the traction torques according to the steer command are applied to the both in-wheel motors in opposite direction each other, the front wheels are to be steered to control the vehicle. The experimental vehicle provided by this steering system is developed in order to prove experimentally how the simultaneous use of the motors for the traction and the steering for the steer-by-wire in the micro electric vehicle is available. The responses of the steering system and the electric vehicle to several steer inputs are investigated to find out the effects of the design parameters of the system on the steering characteristics.

The Department of System Design Engineering of KAIT has focused on “Product Oriented Engineering Education (POEE)” in the student educational program since its establishment. An automobile is a good example for this subjective product due to its wide integration of the engineering and technologies. From this point of view, the KAIT became the first university participated in the Formula SAE® competition (FSAE) from Japan in 2000 and has been one of the leading universities in FSAE in Japan. Some of key design technologies applied on these FSAE cars from 2001(K01) to 2005(K05) are shown in this paper.

A change of vehicle handling characteristics due to increase of lateral acceleration as well as effects of the steering gain adaptation of VGS to that was analyzed by quasi-steady-state analysis to find out a basic strategy for the adaptive gain scheduling in the VGS. A study using a simple fixed base type of simulator showed the upper and lower limit of the appropriate gain of the steering system. A computer simulation study on lane-change response of the driver-vehicle-system gave us a view that there exists a suitable gain setting for the VGS from a view point of driver-vehicle-system stability.

A theoretical analysis on the fundamental requirements for the functional design of the maglev vehicle undercarriage with mechanical air-gap control system is dealt with. One of the requirements introduced is described by the relation among the primary suspension spring rate, the attractive force characteristics of the magnet and the control lever ratio. Another requirement is a dimensional relation among the location of the magnets, the vertical guide-wheels and the primary suspension springs. In order to discuss the dynamic characteristics of the vehicle, a computer simulation of the vehicle response to guideway roughness random input is carried out. Attention is focused on the influence of the system parameters on power spectra of the vehicle responses.

Considering that the effects of the change of vehicle speed can be disregarded in a short period of time, the equilibrium equations of the vehicle motion of constant lateral and longitudinal accelerations which describe the vehicle turning behaviors in acceleration and in braking are developed. Solving the equilibrium equations the characteristic lines of the radii of path curvature versus vehicle speed for various longitudinal accelerations and the relations of longitudinal acceleration to lateral one under a certain vehicle speed with fixed steering angle are obtained for the vehicles with various types of drive arrangements. The effects of the locked differential(s), the longitudinal load transfer, the tire vertical stiffness, the suspension compliance steer due to the longitudinal tire force and front to rear brake balance on the vehicle turning behaviors in acceleration and in braking are investigated. A calculated result shows satisfactory agreements with the computer simulation.

It becomes clear that the suction coefficient of oil, K, and the sealing characteristic constant, Φ (=fG-1/3), are closely connected with the rubbing surface state of oil seals. And, investigations have done on K-, Φ-value, etc. in oil seals after the practical use in automobiles and the results have been compared with the test results in the laboratory.

In this paper a computer simulation study on the effects of steering parameters on lateral dynamics of the guideway bus to contribute to a development practice of designing optimum steering control system are dealt with. A stability limit of vehicle lateral motion is analyzed and an emphasis is laid on the effects of moment of inertia of a conventional steering wheel and lateral elasticity of the guide rail which have proven to reduce the critical vehicle speed. It is pointed out conclusively that a normal bus equipped with additional simple guidance equipments can be guided smoothly on a simple guideway at adequately high vehicle speed.