Citation: De Breuker, R.; Mkhoyan, T.; Nazeer, N.; Stuber, V.; Wang, X; Mkhoyan, I.; Groves, R.; van der Zwaag, S.; Sodja, J. Overview of the SmartX Wing Technology Integrator. Actuators 2022, 11, 302. https://doi.org/10.3390/ act11100302 Academic Editor: Ronald M. Barrett Received: 1 September 2022 Accepted: 19 October 2022 Published: 20 October 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 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/). actuators Article Overview of the SmartX Wing Technology Integrator Roeland De Breuker * , Tigran Mkhoyan , Nakash Nazeer , Vincent Stuber , Xuerui Wang , Iren Mkhoyan, Roger Groves , Sybrand van der Zwaag and Jurij Sodja Department of Aerospace Structures and Materials, Faculty of Aerospace Engineering, Delft University of Technology, 2629HS Delft, The Netherlands * Correspondence: r.debreuker@tudelft.nl; Tel.: +31-15-278-56-27 Abstract: This article describes the challenges of integrating smart sensing, actuation, and control concepts into an over-sensed and over-actuated technology integrator. This technology integrator has more control inputs than the expected responses or outputs (over-actuated), and its every state is measured using more than one sensor system (over-sensed). The hardware integration platform is chosen to be a wind tunnel model of a low-speed aircraft wing such that it can be tested in a large university-level wind tunnel. This hardware technology integrator is designed for multiple objectives. The nature of these objectives is aerodynamic, structural, and aeroelastic, or, more specifically; drag reduction, static and dynamics loads control, aeroelastic stability control, and lift control. Enabling technologies, such as morphing, piezoelectric actuation and sensing, and fibre- optic sensing are selected to fulfil the mentioned objectives. The technology integration challenges are morphing, actuation integration, sensor integration, software and data integration, and control system integration. The built demonstrator shows the intended level of technology integration. Keywords: autonomous wing; over-actuated wing; over-sensed wing; technology demonstrator 1. Introduction Smart structures have been present since the dawn of aviation. The first heavier- than-air powered flight by the Wright brothers in 1903 was carried out with an aircraft that was able to twist morph its wings. Morphing was quite common in those pioneering years. However, aircraft became larger and heavier, and the wing loading increased. This necessitated the wings to become stiffer to carry the increased loads, and this increased stiffness prevented the wing from morphing. The separation of functionalities in aircraft wings was introduced, where the wing load-carrying structure was separated from the rigid wing movables, which enabled the wing’s high-lift and rolling capabilities [1]. Only a handful of later morphing aircraft examples can be found, and they are mainly limited to experimental or military aircraft. Iconic examples are the F14 Tomcat and F111 Aardvark. However, since the 1980s, a renewed interest in smart structures for aviation has originated from the Active Flexible Wing (AFW), the Active Aeroelastic Wing (AAW), and the Aircraft Morphing and the Morphing Aircraft Structures programmes of the National Aeronautics and Space Administration (NASA) and the Defense Advanced Research Projects Agency (DARPA), amongst others [2–6]. On the civil aircraft side, the interest in smart structures for aviation has spiked in the European Union (EU) Framework Programmes (FP), more specifically FP5, FP6, FP7, and H2020. Much of the research in these programmes was focused on individual non-integrated morphing, actuation, or sensing concepts. These programmes focused on topics such as, but not limited to, morphing using compliant mech- anisms [7], span and chord morphing mechanisms [8], or aircraft sensing methods [9]. Only occasionally did hardware demonstrators contain multiple actuation or sensing concepts. An example is the EU FP7 Smart Intelligent Aircraft Structures (SARISTU) project [10]. More examples are the X-HALE nonlinear aeroelastic flying platform developed by Cesnik and co-workers. They focused on shape control, manoeuvre and gust load control, and Actuators 2022, 11, 302. https://doi.org/10.3390/act11100302 https://www.mdpi.com/journal/actuators