Design of electromagnetic shock absorbers for automotive suspensions

Abstract

Electromechanical dampers seem to be a valid alternative to conventional shock absorbers for automotive suspensions. They are based on linear or rotative electric motors. If they are of the DC-brushless type, the shock absorber can be devised by shunting its electric terminals with a resistive load. The damping force can be modified by acting on the added resistance. To supply the required damping force without exceeding in size and weight, a mechanical or hydraulic system that amplifies the speed is required. This paper illustrates the modelling and design of such electromechanical shock absorbers. This paper is devoted to describe an integrated design procedure of the electrical and mechanical parameters with the objective of optimising the device performance. The application to a C class front suspension car has shown promising results in terms of size, weight and performance.

Keywords:

• active suspension
• mechatronics
• electromagnetics
• semi-active suspension

Acknowledgements

This study was sponsored at the Mechatronics Laboratory of Politecnico di Torino by the FIAT Auto company under the capable direction of Ing. Stefano Re Fiorentin and Ing. Guglielmo Caviasso. Their contributions to this work are gratefully acknowledged.