**Alessandro Casavola ‡, Francesco Tedesco ‡ and Pasquale Vaglica \***

Modeling, Electronics and Systems (DIMES), Department of Informatics, University of Calabria, Via P. Bucci, 42/C, 87036 Rende (CS), Italy; a.casavola@dimes.unical.it (A.C.); ftedesco@dimes.unical.it (F.T.)


Received: 17 April 2020; Accepted: 20 May 2020; Published: 22 May 2020

**Abstract:** Regenerative suspension systems, unlike traditional passive, semi-active or active setups, are able to convert the traditionally wasted kinetic energy into electricity. This paper discusses flexible multi-objective control design strategies based on LMI formulations to suitably trade-off between the usual road handling and ride comfort performance and the amount of energy to be harvested. An electromechanical regenerative vehicle suspension system is considered where the shock absorber of each wheel is replaced by a linear electrical motor which is actively governed. It is shown by simulations that multivariable centralized control laws designed on the basis of a full-car model of the suspension system are able to achieve larger amount of harvested energy under identical ride comfort prescriptions with respect to scalar decentralized control strategies, designed on the basis of a single quarter-car model and implemented independently on each wheel in a decentralized way. Improvements up to 40% and 20% of harvested energy are respectively achievable by the centralized multivariable *H*<sup>2</sup> and *H*<sup>∞</sup> optimal controllers under the same test conditions.

**Keywords:** regenerative shock absorbers; energy harvesting; active control of automobile suspension systems
