Morphing Wings Using Macro Fiber Composites

Macro Fiber Composites (MFC) are smart materials that have one or more properties that can be altered by an external stimulus such as magnetic and electric fields, temperature and pH, in order to meet specific requirements or conditions. Today, smart materials are used in a variety of applications in the aerospace industry, locomotives, and in the medical field to generate better performance for its devices. The objective of this paper is to describe an experiment on morphing a wing using MFCs. The materials needed to achieve this project are illustrated in the experimental setup of this paper. Additionally, the author expects to be able to morph the wing of the aircraft and compare its acquired data to that of a general aircraft to determine which one has the best performance

Power Requirements for Bi-harmonic Amplitude and Bias Modulation Control of a Flapping Wing Micro Air Vehicle

Flapping wing micro air vehicles (FWMAV) have been a growing field in the research of micro air vehicles, but little emphasis has been placed on control theory. Research is ongoing on how to power FWMAVs where mass is a major area of concern. However, there is little research on the power requirements for the controllers to manipulate the wings of a FWMAV. A novel control theory, BABM, allows two actuators to produce forces and moments in five of the FWMAV\u27s six DOF. Several FWMAV prototypes were constructed and tested on a six-component balance. Data was collected for varying control parameters and the generated forces were measured. The results mapped control parameters to different degrees of freedom. The force required to generate desirable motion and power required to generate that motion was plotted and evaluated. These results can be used to generate a minimum power controller in the future. The results showed that BABM control required a 26% increase in power in order to increase lift by 22%. The lift increase was accomplished by increasing the amplitude by 10% over the established baseline. The data also showed that varying some parameters actually decreased the power requirements, allowing other parameters to increase which in turn would enable more complex maneuvers. For instance, an asymmetric change in split-cycle shift of + or - 0.25 decreased the power required by 14% and decreased the lift by 25%. Changing the stroke bias to + or - 0.75 had a negligible effect on power but decreased the lift by 27%. Furthermore, the data identified certain parameter combinations which resulted in other forces and moments. These results identified how BABM be used as a control theory for the control of FWMAVs

Piezoelectric wind power harnessing – an overview

As fossil energy resources deplete, wind energy gains ever more importance. Recently, piezoelectric energy harvesting methods are emerging with the advancements in piezoelectric materials and its storage elements. Piezoelectric materials can be utilized to convert kinetic energy to electrical energy. Utilization of piezoelectric wind harvesting is a rather new means to convert renewable wind energy to electricity. Piezoelectric generators are typically low cost and easy to maintain. This work illustrates an overview of piezoelectric wind harvesting technology. In wind harvesting, piezoelectric material choice is of the first order of importance. Due to their strain rate, robustness is a concern. For optimum energy harvesting efficiency resonant frequency of the selected materials and overall system configuration plays important role. In this work, existing piezoelectric wind generators are grouped and presented in following categories: leaf type, rotary type, rotary to linear type and beam type wind generators

Synergistic Smart Morphing Aileron

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106472/1/AIAA2013-1512.pd

Development of Optimized Piezoelectric Bending Actuators for Use in an Insect Sized Flapping Wing Micro Air Vehicle

Piezoelectric bimorph actuators, as opposed to rotary electric motors, have been suggested as an actuation mechanism for flapping wing micro air vehicles (FWMAVs) because they exhibit favorable characteristics such as low weight, rapidly adaptable frequencies, lower acoustic signature, and controllable flapping amplitudes. Research at the Air Force Research Labs and the Air Force Institute of Technology has shown that by using one actuator per wing, up to five degrees of freedom are possible. However, due to the weight constraints on a FWMAV, the piezoelectric bimorph actuators need to be fully optimized to support free flight. This study focused on three areas of investigation in order to optimize the piezoelectric actuators: validating and improving analytical models that have been previously suggested for the performance of piezoelectric bimorph actuators; identifying the repeatability and reliability of current custom manufacturing techniques; and determining the failure criteria for piezoelectric actuators so that they can be driven at the highest possible voltage. Through the optimization, manufacturing, and performance testing of piezoelectric bimorphs, analytical models have been adjusted to fit the empirical data to yield minimum mass actuators that could potentially meet the mechanical energy requirements in a FWMAV. For custom manufactured actuators, optimized tapered actuators with an end extension showed an 89.5% energy density improvement over optimized rectangular actuators and a 19.5% improvement in energy density over commercially available actuators

Efficacy of Flapping-wing Flight Via Dual Piezoelectric Actuation

A novel piezoelectric-actuated wing system featuring dual actuators for increased wing control is presented and evaluated for its forward-flight characteristics via theoretical modeling and physical wind tunnel testing. Flapping wing aerial systems serve as a middle ground between the traditional fixed-wing and rotary systems. Flapping wing aerial systems exhibit high maneuverability and stability at low speeds (like rotary systems) while maintaining increased efficiency (like fixed-wing systems). Flapping wings also eliminate the necessity of dangerous fast-moving propellers and open the door to actuation mechanisms other than traditional motors. This research explores one of these alternatives: the piezoelectric bending actuator. Piezoelectric materials produce a mechanical strain when an electric charge is applied. With an applied sinusoidal voltage, cantilevered bending piezoelectric actuators create oscillatory motion at the free end that can be translated into wing movement much more directly than a rotational motor. This direct actuation eliminates the need for gears and provides a mechanism for reducing the system\u27s weight. Furthermore, the simplified mechanism can improve robustness by removing contact surfaces that can become clogged or worn (e.g., using gears). While piezoelectric flapping-wing flight has many potential benefits, the combination has only been explored in insect-inspired hovering flight. This work explores the feasibility of larger, forward-flight systems to identify a framework for piezoelectrically-driven flapping-wing vehicles with wing-bending control. Theoretical and experimental analysis methods are presented to study piezoelectric flapping wing motion characteristics for lift and drag effects in flapping-wing aerial systems

A comparative review of artificial muscles for microsystem applications

Artificial muscles are capable of generating actuation in microsystems with outstanding compliance. Recent years have witnessed a growing academic interest in artificial muscles and their application in many areas, such as soft robotics and biomedical devices. This paper aims to provide a comparative review of recent advances in artificial muscle based on various operating mechanisms. The advantages and limitations of each operating mechanism are analyzed and compared. According to the unique application requirements and electrical and mechanical properties of the muscle types, we suggest suitable artificial muscle mechanisms for specific microsystem applications. Finally, we discuss potential strategies for energy delivery, conversion, and storage to promote the energy autonomy of microrobotic systems at a system level

Closed-Loop Control of Constrained Flapping Wing Micro Air Vehicles

Micro air vehicles are vehicles with a maximum dimension of 15 cm or less, so they are ideal in confined spaces such as indoors, urban canyons, and caves. Considerable research has been invested in the areas of unsteady and low Reynolds number aerodynamics, as well as techniques to fabricate small scale prototypes. Control of these vehicles has been less studied, and most control techniques proposed have only been implemented within simulations without concern for power requirements, sensors and observers, or actual hardware demonstrations. In this work, power requirements while using a piezo-driven, resonant flapping wing control scheme, Bi-harmonic Amplitude and Bias Modulation, were studied. In addition, the power efficiency versus flapping frequency was studied and shown to be maximized while flapping at the piezo-driven system\u27s resonance. Then prototype hardware of varying designs was used to capture the impact of a specific component of the flapping wing micro air vehicle, the passive rotation joint. Finally, closed-loop control of different constrained configurations was demonstrated using the resonant flapping Bi-harmonic Amplitude and Bias Modulation scheme with the optimized hardware. This work is important in the development and understanding of eventual free-flight capable flapping wing micro air vehicle

Analysis of morphing, multi-stable structures actuated by piezoelectric patches

Tese de mestrado. Engenharia Mecânica. Faculdade de Engenharia. Universidade do Porto, Universidade de Bristol. 200