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A control law for integrating 4WS and 4WD systems is presented. It is based upon a non-linear vehicle model in which the lateral force acting on the tires changes according to the tire slip angle, slip ratio and the load. The purpose of the system is to make the actual yaw rate follow the desired yaw rate. A two-degree-of-freedom control structure has been devised and variable transformation is used to linearize the non-linear model so that H∞ control theory can be applied to design the feedback compensator. A new control theory is used to calculate optimum command values for the 4WS and 4WD actuators. Moreover, adaptive logic is added to reduce the desired yaw rate as the tires approach the limits of adhesion. Simulations and experiments prove the system greatly improves stability during cornering.

Eliminating brake squeal generated during brake application is an important task for the improvement of comfort in the vehicle. There has been a lot of research made on the problem of brake squeal in the past. And most of the papers presented elaborate on low frequency brake squeal (2-3kHz). However, brake squeal has often the high-frequency vibration. For this reason, we have made research into the high-frequency brake squeal (5-10kHz). Double-Pulsed Laser Holography is a useful method for visualizing small vibration of brake components during brake squeal generation. The results obtained using Holographic Interferometry show the rotaing disc vibrates in the bending mode with diametral nodes. Consequently, we think that the modification of brake disc can eliminate brake squeal, which is caused by self-excited vibration. Then we have calculated natural frequency and its vibration mode of a circular-plate added mass.

A system to measure transient temperature distribution on the brake disc rotor at high speed braking has been developed and its measuring principle and configuration were discussed in this paper. This system consists of two revolution sensors and two sets of optical fiber array, photoelectric elements, and microprocessor, which fiber array is so arranged that it faces the brake disc rotor. This new system has the following features: (1) Measuring is made using a visible radiation wavelength range for red hot temperatures higher than 550°C.