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The ride values of passenger cars are investigated for Korean subjects based on the vibration of the human bodies. When three subjects are excited by driving a vehicle on road, their responses of acceleration are measured at 12 points on their bodies according to Griffin's 12 axis system (3 translational axes on a seat surface, 3 rotational axes on a seat surface, 3 translational axes at the seat back and the 3 translational axes at the feet). Since one of the most important parameters for ride comfort is the level and duration of the root mean square acceleration experienced, the ride values, such as the seat effective amplitude transmissibility, the component ride value, and the overall ride value based on acceleration root mean square are evaluated for different four vehicles using frequency weighing functions and axis multiplying factors. The ride indices are also studied considering to the seat dynamic characteristics with subjects.

The ride values of seven cars(six passenger car and one RV car) are evaluated for 4 subjects based on the vibration of the bodies. And the seat qualities are investigated with the SEAT(seat effective amplitude transmissibility) value. The evaluated values are arranged as DB in html files. Since one of the most important parameters for ride comfort is the level and duration of the root mean square acceleration experienced, the acceleration responses of subjects are measured at 8 points on their bodies(3 Translational axes on the seat surface, 3 translational axes at the feet and 2 axes(x,z) at the backrest) when the subjects are excited by driving a vehicle on the road. The ride values such as the overall ride value, the component ride values and the seat effective amplitude transmissibility based on acceleration root mean square are evaluated for different seven vehicles using frequency weighting functions and axis multiplying factors.

Most passenger vehicles employ manual or automatic transmission in their power train. Recently, some automated geared transmission including the dual clutch transmission is gaining popularity for its fuel efficiency and smooth driving as well as convenience. In this study, we are proposing a new much simplified clutchless geared transmission which may transmit most powerful torque employing the power-merge planetary gear system to the final drive during gear shift with excellent smoothness in the transmitted torque. This transmission might work for the most kinds of vehicles having internal combustion engine including the hybrid vehicles.

The objective of this study is to develop a neuro controlled active suspension for the ride quality improvement. The performance index of the optimal control is represented as the frequency-shaped using Parseval's theorem. The incorporation of frequency-dependent weighting matrices allow one to emphasize the specific variables related to the vibrations of the specific bands of frequencies. Once the active control law is obtained, we use the artificial neural networks to train the neuro controller to learn the relation of road input and control force. From the numerical results, we found that back propagation learning does good pattern matching and the neuro controlled suspension may reduce the vertical acceleration of the driver's seat and sprung mass motions significantly at desired bands of frequencies.

This paper deals with the determination of the seat sponge parameters by using the estimated nine degree-of-freedom biodynamic model. The suggested nine DOF model has multiple outputs that include the major axes for evaluating the ride quality in vehicles such as z-axis of the floor, hip, and x-axis of the back, in addition to the z-axis of the head for describing the whole-body vibration. It is intended to resemble the sitting posture with backrest support. Three experiments were executed to validate the proposed models. The first one was to measure the acceleration of the floor and hip in z-axis, the back in x-axis, and the head in z-axis under exciter. From this measurement, the transmissibilities of each subject were obtained. The second one was the measurement of the joint position by the device having pointer, and contact point between human body and seat by pressure sensor. The third one was the dropping test to measure the seat and back cushion.