Modeling of Coil Springs Using Parallel Mechanisms

Traditionally coil springs were used for applications to exert one-dimensional force along a given spring coil axis. However, in recent years, there has been an increasing trend in using coil springs to provide forces in a multi-dimensional space. In this paper, an approach to construct a model of a coil spring for suspension systems using a spatial six degree-of-freedom parallel mechanism is presented. In kinematics and dynamics simulation, the use of a parallel mechanism to model a coil spring allows a designer to simulate six degrees of freedom spring characteristics with vehicle kinematics without using FEA feature embedded in the simulation software. This requires a significant amount of computational load and maybe a file format converter. If an actual parallel mechanism is available and inserted into an experimental suspension system in place of a coil spring, it can be used as a device to generate various forces and torques between the upper and lower spring seats to study desirable characteristics useful for designing coil springs. Examples are presented to simulate responses of an automobile suspension system using this parallel mechanism based spring model.