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Ch68-I044963.fm Page 333 Tuesday, August 1, 2006 8:30 PM
1, 2006
Tuesday, August
Page 333
8:30 PM
Ch68-I044963.fm
333
333
ACTIVE SUSPENSION SYSTEM
WITH HIGH-SPEED ON/OFF VALVE
(APPLICATION OF PREVIEW CONTROL
WITH ADAPTIVE DIGITAL FILTER)

Hironao YAMADA ' and Takayoshi MUTO 1
1
Department of Human and Information Systems, Gifu University,
1-1 Yanagido, Gifu 501-1193, Japan

ABSTRACT

The aim of this study is to propose an active control hydro-pneumatic suspension system composed of
high speed on/off solenoid valves. In order to realize a robust control system, we adopted preview
control method utilizing an ADF (Adaptive Digital Filter). The experiment was performed on a bench
system which physically simulates induced vibrations from the road. These results confirmed that in
the case of the preview control method, the damping efficiency is higher than in the case using the
conventional sky-hook control method. Furthermore, the control performance of preview control using
an ADF is superior to the conventional preview control system. Therefore, it is expected that the
active suspension system, which is developed in this study, could produced at low cost and achieve a
high level of reliability.

KEYWORDS

Preview Control, Adaptive Digital Filter, ON/OFF Valve, Active Suspension, PWM Control.

INTRODUCTION

In recent years, an active control suspension system has come into use thanks to progress in the
(l) (4>
development of micro processors, sensors, and actuators " . By applying these new techniques to
the active suspension system, it is expected that the both riding comfort and vehicle control stability
will be improved. However, one of the problems associated with these developments is that the
introduction of active suspension inevitably makes vehicles complex, heavy, and expensive.
Conventional active suspension systems normally use a pressure control valve or a servo valve as a
system control device. These valves, however, have defects in that they are expensive and have a
weakness in oil contamination. In contrast to these valves, a fast switching on/off valve can be
considered an attractive device for overcoming the above-mentioned defects. The reason for this is