Katsuhiro Asano

Estimation of automotive tire force characteristics using wheel velocity

Abstract It is important to estimate friction force characteristics between tire and road in order to improve the control performance of a vehicle in critical motions. In this paper, an estimation method which estimates parameters concerned with a friction force margin is proposed by applying the on-line least-squares method to wheel rotational velocities. The effect of the estimation is evaluated by applying the method to the braking control.

High Performance Motor Drive Technologies for Hybrid Vehicles

In this paper, latest motor drive technologies used for hybrid vehicles (HV), which are high output motor control and variable voltage system, will be introduced. Authors have researched and developed motor drive technologies through development of hybrid vehicles, which has been put into practical use to production vehicle. The developed motor drive system has the features of high efficiency, high power/weight ratio, and low-cost.

Observer based estimation of parameter variations and its application to tyre pressure diagnosis

Abstract This paper deals with an estimation method of parameter variations of dynamic systems based on the disturbance observer. The disturbance observer is designed to estimate the parameter variations as disturbances. The simple least squares method can extract the parameter variations from the estimated disturbances which include external disturbances and noise. The proposed method is applied to the tyre pressure diagnosis system which can detect underinflated tyres in every situation such as a puncture and natural leaks using wheel speed sensors already provided for anti-lock brake system. Several experimental results are shown to confirm the effectiveness of the method.

Model Following Control of Hybrid 4WD Vehicles

Abstract This paper presents a method to design a rear wheel torque control system for hybrid four wheel drive vehicles (H4WD) and the results of its construction to an experimental vehicle. In the H4WD the front wheels are driven by an engine and the rear wheels are independently driven by two motors. The rear wheel torque control system employs a model following approach in which the yaw rate of the vehicle is controlled to track a reference yaw rate. The reference yaw rate is produced from a yaw rate reference model, a first order lag system which has a steering angle as the input signal. From results of computer simulations and experiments, this control system has been found to decrease the deflection of the vehicle due to lateral force disturbance such as lateral wind gusts. It also improves both the stahility and the controllability of the vehicle.

Induction-motor-driven vehicle with vibration suppression using wheel torque observer

The authors describe an induction-motor-driven vehicle, in which the regulator and the wheel torque observer suppress vibrations occurring when induction motors drive the power train of the vehicle under overload at high speed. The target system of the study is a hybrid vehicle consisting of a front engine-driven-system and two rear motor-driven-systems, which are designed to improve the driving stability. The stability of the total system including vector control system and mechanical system is analyzed.<<ETX>>