Automotive Electronics Handbook, Second Edition
Use this guide to become an instant expert on today's leading edge auto electronic technologies--stability control, object detection, collision warning, adaptive cruise control, and more.
TABLE OF CONTENTS Automotive Electronics Handbook, Second Edition
Chapter 18: Suspension Control
Akatsu Yohsuke
Manager, Vehicle Research Laboratory
Nissan Motor Co., Ltd.
The function of a suspension system in an automobile is to improve ride comfort and stability. An important consideration in suspension design is how to obtain both improved ride comfort and stability, since they are normally in conflict. Advances in electronic control technology, applied to the automobile, can resolve this conflict.
18.1 Shock Absorber Control System
During the past 20 years, many different damping control systems have been studied. The main purpose of all these systems is to select the optimum damping force for various driving conditions. The first function of a shock absorber is to control vehicle movement against inertial forces, such as roll when the vehicle turns and pitch when the vehicle is braked. The second function is to prevent vehicle vibration caused by road surface inputs. To satisfy both functions it is necessary to control damping forces.
There are three basic parts of a damping control system: a damping control device (actuator), sensors, and software (control strategy). Optimum damping forces should be set for various running conditions in order to improve ride comfort and handling stability.
18.1.1 System Configuration
One of the damping control system configurations is shown in Fig. 18.1. This system uses five sensors, including a supersonic road sensor, to detect running conditions. Control signals are sent to adjust the damping force of the variable shock absorbers to optimum values. A main advantage to this type of system is that, through the use of a...
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