Norio Iwama

Vehicle integrated control for steering and traction systems by m-synthesis

Abstract This study aims at improving vehicle maneuverability in global turning motions including critical turning, by an integrated control strategy which coordinates steering and traction systems. The vehicle model expressing global turning motions has nonlinear dynamics, and this makes it impossible to apply the linear control theory directly. In this paper, the nonlinear vehicle model which also considers transient characteristics of tires is linearized by a nonlinear transformation. The vehicle yaw motion is expressed by a first-order linear model, and μ-synthesis is applied to the model. As a result, the integrated control strategy which compensates robust stability against perturbations generated under various driving environments is obtained. Some experiments indicate that the integrated control improves vehicle performance.

Experimental Study of System Optimization for Suppression of Vehicle Vibration

SUMMARY The improvements of ride comfort and vehicle maneuverability in the vehicle design can be achieved by using an active suspension. However, the problems in such a control are the complex control logic because of the control laws incompatible with the improvements of ride comfort and maneuverability, and the cost increase because of various sensors to be attached. Therefore, we examined the control abilities of ride comfort and maneuverability on a unique control law using frequency shaped LQ, and controlled the characteristic of the contact between tire and road without a road displacement sensor

Robust Coordinated Control for 4-Wheel-Steering and 4-Wheel-Drive Vehicle

Abstract This study aims at improving vehicle maneuverability of global turning motions including critical turning, by an integrated control strategy which coordinates steering and traction systems. The vehicle model expressing global turning motions has nonlinear dynamics, and this makes it impossible to apply the linear control theory directly. In this paper, the nonlinear vehicle model which also includes transient characteristics of tires is linearized by a nonlinear transformation, and μ synthesis is applied lo the linear model. As a result, the integrated control strategy which compensates robust stability against perturbations generated under various driving environments is obtained.

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>>

Study of Semiactive Control by Optimum Damping Adjustment. Suspension Control Using Frequency-Shapes Functionals.

There are many proposed control methods that are intended to achieve more marked ride comfort in vehicle suspension systems. In these control methods, a strict trade-off between human sensitiveness and vehicle attitude exists and it is quite important to choose the kinds of performance indexes for vibration control. Aiming at improvement in both ride comfort and vehicle attitude characteristics, frequency shaped-functionals are applied to suspension control systems. As a result of the study, marked improvement in performance is confirmed by both simulation and experimental studies.