Citation: Moutsopoulou, A.; Stavroulakis, G.E.; Petousis, M.; Vidakis, N.; Pouliezos, A. Smart Structures Innovations Using Robust Control Methods. Appl. Mech. 2023, 4, 856–869. https://doi.org/10.3390/ applmech4030044 Received: 10 June 2023 Revised: 9 July 2023 Accepted: 18 July 2023 Published: 19 July 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Communication Smart Structures Innovations Using Robust Control Methods Amalia Moutsopoulou 1, *, Georgios E. Stavroulakis 2 , Markos Petousis 1 , Nectarios Vidakis 1 and Anastasios Pouliezos 2 1 Department of Mechanical Engineering, Hellenic Mediterranean University, Estavromenos, 71410 Heraklion,Greece; markospetousis@hmu.gr (M.P.); vidakis@hmu.gr (N.V.) 2 Department of Production Engineering and Management, Technical University of Crete, Kounoupidianna, 73100 Chania, Greece; gestavr@dpem.tuc.gr (G.E.S.); tasos@dpem.tuc.gr (A.P.) * Correspondence: amalia@hmu.gr; Tel.: +30-2810379702 Abstract: This study’s goal is to utilize robust control theory to effectively mitigate structural oscilla- tions in smart structures. While modeling the structures, two-dimensional finite elements are used to account for system uncertainty. Advanced control methods are used to completely reduce vibration. Complete vibration suppression is achieved using advanced control techniques. In comparison to traditional control approaches, Hinfinity techniques offer the benefit of being easily adaptable to issues with multivariate systems. It is challenging to simultaneously optimize robust performance and robust stabilization. One technique that approaches the goal of achieving robust performance in mitigating structural oscillations in smart structures is H-infinity control. H-infinity control em- powers control designers by enabling them to utilize traditional loop-shaping techniques on the multi-variable frequency response. This approach enhances the robustness of the control system, allowing it to better handle uncertainties and disturbances while achieving desired performance objec- tives. By leveraging H-infinity control, control designers can effectively shape the system’s frequency response to enhance stability, tracking performance, disturbance rejection, and overall robustness. Keywords: robust control; smart structures; uncertainty modelling; reduce oscillations 1. Introduction Smart structures have garnered significant attention in recent years due to their im- mense potential and wide-ranging applications. A smart structure is defined as one that intelligently perceives mechanical disturbances and automatically reacts to them by re- ducing oscillations [1–3]. The field of smart structures has seen a big increase in recent years [3–6]. In this work, an intelligent structure that has integrated actuators and sensors that are capable of damping the oscillations is presented [7–10]. Dynamic loads such as wind forces are applied and finite element analysis is performed [1,6,11,12]. Advanced testing techniques such as robust control theory are used. It is then applied to engineering applications that are made with smart materials such as piezoelectric material. In these constructions, both sensors and actuators are integrated; the actuators achieve the suppres- sion of the oscillation [9–11]. Many researchers have mainly dealt with the modeling of these constructions but also with the application of advanced control techniques [2,12–16]. Modeling and control techniques are often used for the analysis of optimization of the materials response [17–21]. In addition, many researchers have engaged in research on com- posite concrete structures in the frequency domain and have presented very good results in solving optimization problems [22,23] in this field; they are many practical applications from important researchers [24,25]. Our paper provides the innovation in the piezoelectric intelligent structures with robust control theory. We achieve complete vibration suppression even for uncertainty modeling of the smart structure. This work has provided many innovations in the suppres- sion of oscillations with the application of smart materials: Appl. Mech. 2023, 4, 856–869. https://doi.org/10.3390/applmech4030044 https://www.mdpi.com/journal/applmech