A Self–Tuning Intelligent Controller for a Smart Actuation Mechanism of a Morphing Wing Based on Shape Memory Alloys

Abstract

The paper exposes some of the results obtained in a major research project related to the design, development, and experimental testing of a morphing wing demonstrator, with the main focus on the development of the automatic control of the actuation system, on its integration into the experimental developed morphing wing system, and on the gain related to the extension of the laminar flow over the wing upper surface when it was morphed based on this control system. The project was a multidisciplinary one, being realized in collaboration between several Canadian research teams coming from universities, research institutes, and industrial entities. The project’s general aim was to reduce the operating costs for the new generation of aircraft via fuel economy in flight and also to improve aircraft performance, expand its flight envelope, replace conventional control surfaces, reduce drag to improve range, and reduce vibrations and flutter. In this regard, the research team realized theoretical studies, accompanied by the development and wind tunnel experimental testing of a rectangular wing model equipped with a morphing skin, electrical smart actuators, and pressure sensors. The wing model was designed to be actively controlled so as to change its shape and produce the expansion of laminar flow on its upper surface. The actuation mechanism used to change the wing shape by morphing its flexible upper surface (manufactured from composite materials) is based on Shape Memory Alloys (SMA) actuators. Shown here are the smart mechanism used to actuate the wing’s upper surface, the design of the intelligent actuation control concept, which uses a self–tuning fuzzy logic Proportional–Integral–Derivative plus conventional On–Off controller, and some of the results provided by the wind tunnel experimental testing of the model equipped with the intelligent controlled actuation system. The control mechanism uses two fuzzy logic controllers, one used as the main controller and the other one as the tuning controller, having the role of adjusting (to tune) the coefficients involved in the operation of the main controller. The control system also took into account the physical limitations of the SMA actuators, including a software protection section for the SMA wires, implemented by using a temperature limiter and by saturating the electrical current powering the actuators. The On–Off component of the integrated controller deactivates or activates the heating phase of the SMA wires, a situation when the actuator passes into the cooling phase or is controlled by the Self–Tuning Fuzzy Logic Controller.

Autonomous Shape Decision Making of Morphing Aircraft with Improved Reinforcement Learning

“…Combining the above model with the DDPG algorithm, the shape decision-making algorithm framework of MA based on the DDPG can be obtained as shown in Figure 2. As shown in Figure 2, the environment model of the algorithm is the MA control system shown in Equation (7). The aircraft changes its wingspan and sweep angle according to the morphing strategy obtained by the agent, and the state of MA is fed back to the agent.…”

“…In the control discipline, the research of MA can be divided into three main levels: morphing control, flight control and shape decision making. Among them, the research into morphing control mostly focuses on the morphing airfoil structures, flight dynamics and intelligent materials [6][7][8][9]. The research into flight control assumes that the aircraft shape changes according to the preset change strategy [10][11][12][13].…”

Design and Control of a Shape Memory Alloy-Based Idle Air Control Actuator for a Mid-Size Passenger Vehicle Application

“…The required SMA models to determine the appropriate responses of the actuator include thermal, constitutive, and kinetic models. The models are arranged consecutively to use controlled electric current as the principal input [7,39]. The SME links the models to operate.…”

Study on Fluid–Structure Interaction of a Camber Morphing Wing

“…Due to their high power-to-weight ratio, small size, and simple structure, shape memory alloy actuators are commonly used as one of the preferred actuators for wing variant structure Lv et al [15] proposed a smart structure based on a shape memory alloy for driving the morphing trailing edge, which was validated in a transonic wind tunnel. In 2023, Grigorie et al [27] developed an automatic control technology for an SMA-based actuation system So, it is evident that SMA actuators have tremendous potential in the aviation industry.…”

“…Lv et al [15] proposed a smart structure based on a shape memory alloy for driving the morphing trailing edge, which was validated in a transonic wind tunnel. In 2023, Grigorie et al [27] developed an automatic control technology for an SMA-based actuation system. So, it is evident that SMA actuators have tremendous potential in the aviation industry.…”