Fractional differentiation in passive vibration control

From a single-degree-of-freedom model used to illustrate the concept of vibration isolation, a method to transform the design for suspension into a design for robust controller is presented. Fractional differentiation is used to model viscoelastic behaviour of suspension. The use of fractional differentiation not only permits optimisation of just four suspension parameters, showing the `compactness' of the fractional derivative operator, but also leads to robustness of suspension performance to uncertainty of the sprung mass. As an example, an engine suspension is studied.