Design, characterization, and testing of macro-fiber composite actuators for integration on a fixed-wing UAV

Abstract

Smart materials offer several potential advantages for UAV flight control applications compared to traditional servo actuators. One important benefit is that smart materials are lightweight and can be embedded directly into the structure of a wing or control surface. Therefore, they can reduce the overall weight of the vehicle and eliminate the need for mechanical appendages that may compromise the form factor of the wing, benefits that become more significant as the size of the vehicle decreases. In addition, smart materials can be used to realize continuous camber change of aerodynamic surfaces. Such designs offer improved aerodynamic efficiency compared to the discontinuous deflections of traditional hinged control surfaces driven by servo actuators. In the research discussed in this paper, macro-fiber composite (MFC) aileron actuators are designed for implementation on a medium-scale, fixed-wing UAV in order to achieve roll control. Macro-fiber composites, which consist of piezoceramic fibers and electrodes embedded in an epoxy matrix, are an attractive choice for UAV actuation because they are manufactured as lightweight, thin sheets and, when implemented as bending actuators, can provide both large structural deflections and high bandwidth. In this study, several MFC aileron actuator designs were evaluated through a combination of theoretical and experimental analysis. The current design consists of glass fiber composite ailerons with two unimorph MFC actuators embedded in each aileron to produce upward deflection. Wind tunnel test results are presented to assess the changes in lift and drag coefficients for different levels of MFC aileron actuation. Preparations for open-loop flight testing using a Skywalker UAV with MFC ailerons are also discussed. In addition, the development of a closed-loop, autonomous flight control system for the Skywalker is overviewed in preparation for conducting simulations and flight testing of an autonomous Skywalker with MFC aileron actuators.

Design and Experimental Studies of Flexible Trailing Edge for Variable Camber Morphing Wing

“…Modelling piezoelectric actuators in the unimorph and bimorph set ups has been typically performed under the assumption that it acts as a beam in bending. Figure 2.3 shows a unimorph rigidly supported with the following equations formulated to predict the tip deflection [13]: Kim, Moncayo, Azizi, &Chan, 2014).…”

Development and Testing of an Unmanned Aerial System with Micro-Fiber Composite Actuators

“…As an important initial design decision, it was determined that, rather than attempting to integrate the MFC actuators into the standard foam ailerons on the Skywalker UAV, a simpler implementation would be achieved by fabricating custom ailerons for the UAS 13 . Unimorph and bimorph actuator designs were both considered for the MFC aileron design.…”

Morphing aircraft based on smart materials and structures: A state-of-the-art review

“…In several studies, the camber of the wings of a micro air vehicle (MAV) was altered using piezoelectric composites to change the lift, the drag, and the pitching moment (Bilgen and Friswell, 2014; Heryawan et al, 2005, 2006; Molinari et al, 2015; Paradies and Ciresa, 2009; Prazenica et al, 2014) or to control the roll and pitch by morphing the trailing edge near the wingtips (Bilgen et al, 2007; Probst et al, 2012; Vos et al, 2007); the feasibility of these designs has been demonstrated in flight tests (see Figure 5). An MAV in which the elevators were controlled by piezoelectric composites was constructed and tested in a wind tunnel (Yoon et al, 2006a, 2006b).…”