A novel control strategy for semi-active suspensions with variable damping and stiffness

The problem considered in this paper is the study and the control strategy design of semi-active suspensions featuring the regulation of both damping and stiffness. This work presents an evaluation of the performances and drawbacks achieved by such suspension architecture, also in a non-linear setting (explicitly taking into account the stroke limits of the suspension). This paper then proposes a new comfort-oriented variable-damping-and-stiffness control algorithm, named Stroke-Speed-Threshold-Stiffness-Control (SSTSC), which overcomes the critical trade-off between the choice of the stiffness coefficient and the end-stop hitting. The use of a variable-damping-and-stiffness suspension, together with this algorithm, provides a significant improvement of the comfort performances, if compared with traditional passive suspensions and with more classical variable-damping semi-active suspensions.