Design and Analysis of a Horizontal Quasi-Zero Stiffness Vibration Isolator by Combining Rolling-Ball and Disk Springs in Parallel

Combining disk springs having negative stiffness with a rolling-ball in parallel is proposed in this paper. It is used to reduce the system stiffness and the positioning error in a non-ideal environment. The characteristics of a disk spring are analyzed. The dynamic equation of its motion has been obtained based on Newton's second law. After definition of a error margin, the dynamic equation of the motion can be treated as a Duffing oscillator, and the influences of non-dimensional parameters on the stiffness and transmissibility are studied. The natural frequency and transmissibility are achieved in a linearization range, where the ratio of linear to nonlinear items is small enough. The influence of mass ratio and non-dimensional parameters on natural frequency are analyzed. Finally, a comparison of numerical example demonstrates that the QZS system can realize a lower stiffness within an increased range.