Multi-Rate Sampled-Data Controller Design for Vehicle Active Suspension Systems

In this letter, the multi-rate sampled-data control problem of active suspension systems with three control loops is investigated under the framework of integral quadratic constraints. For this, three main problems are solved. Firstly, the uncertainties caused by sampled-data and time delay are represented by time-varying operators, and the stability equivalent feedback interconnections are given by model transformation. Secondly, the stability and
$H_{\infty }$
performance constraints are given by analyzing the norm of the operators. Thirdly, for the controller design, combined with the cone complement linearization method, the nonconvex matrix inequality is approximately transformed into a convex optimal problem. Finally, the actual experiment shows that the sampled-data frequency of the three control loops of the active suspension systems do not need to be consistent, the controller design is more flexible and the control effect is better.