Post-buckled precompressed (PBP) elements: a new class of flight control actuators enhancing high-speed autonomous VTOL MAVs

Barrett, Ron; McMurtry, Ross; Vos, Roelof; Tiso, Paolo; Breuker, Roeland De

doi:10.1117/12.599083

Cited by 16 publications

(25 citation statements)

References 9 publications

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“…However, the latest developments are pointing towards the direction of non-linear mechanics as long as large displacements are concerned. The work of Schultz and Hyer (2005) and Barrett et al (2005) show clearly a new trend in smart structures for aeronautics. Non-linear mechanics are introduced in order to expand the force-displacement trade off of pzt materials and under this scope the effort to increase the analysis capabilities for such structures is becoming critical.…”

Section: Introductionmentioning

confidence: 97%

Thermal, electrical, mechanical coupled mechanics for initial buckling analysis of smart plates and beams using discrete layer kinematics

Giannopoulos

Santafe

Monreal

et al. 2007

International Journal of Solids and Structures

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Non-linear behavior of smart structures is of interest to researchers due to the possibilities for the elaboration of more effective actuators and sensors based on piezoelectric materials. The aim of the present work, is to present an integrated approach for the buckling behavior of smart beams and plates under multiple loading conditions. In order to present an accurate analysis, a coupled constitutive formulation between thermal, electrical and mechanical fields is elaborated incorporating non-linearity due to large displacements. An 8-node plate element was implemented in combination with discrete layer kinematics (LW) for the through-the-thickness representation of the structure. The issues of the critical buckling load under different electrical conditions as well as thermal and electrical loading are also presented. Experimental results contribute to the verification of the accuracy of the numerical analysis results and of the coupling mechanics in general.

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Section: Introductionmentioning

confidence: 97%

Thermal, electrical, mechanical coupled mechanics for initial buckling analysis of smart plates and beams using discrete layer kinematics

Giannopoulos

Santafe

Monreal

et al. 2007

International Journal of Solids and Structures

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“…This in turn led to a reduction in battery capacity and consequently battery weight. Unlike conventional servoactuators, the PBP actuators were solid state, so part count, slop and deadband were one to two orders of magnitude lower [13]. Table 1 shows how PBP actuators compare to conventional electromechanical servoactuators.…”

Section: Integration Characteristics and Comparisonmentioning

confidence: 99%

“…Semi-analytic models based on a Rayleigh-Ritz approach were shown to be beneficial when relatively complicated boundary conditions applied [25]. Closed form solutions were conceived for compressed beams in simply supported configurations [13,14]. These solutions are now expanded to cantilevered beams that experience more complex boundary conditions.…”

Section: Introductionmentioning

confidence: 99%

Post-buckled precompressed elements: a new class of control actuators for morphing wing UAVs

Vos¹,

Barrett²,

Breuker³

et al. 2007

Smart Mater. Struct.

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This paper describes how post-buckled precompressed (PBP) piezoelectric bender actuators are employed in a deformable wing structure to manipulate its camber distribution and thereby induce roll control on a subscale UAV. By applying axial compression to piezoelectric bimorph bender actuators, significantly higher deflections can be achieved than for conventional piezoelectric bender actuators. Classical laminated plate theory is shown to capture the behavior of the unloaded elements. A Newtonian deflection model employing nonlinear structural relations is demonstrated to predict the behavior of the PBP elements accurately. A proof of concept 100 mm (3.94 ) span wing employing two outboard PBP actuator sets and a highly compliant latex skin was fabricated. Bench tests showed that, with a wing chord of 145 mm (5.8 ) and an axial compression of 70.7 gmf mm −1 , deflection levels increased by more than a factor of 2 to 15.25 • peak-to-peak, with a corner frequency of 34 Hz (an order of magnitude higher than conventional subscale servoactuators). A 1.4 m span subscale UAV was equipped with two PBP morphing panels at the outboard stations, each measuring 230 mm (9.1 ) in span. Flight testing was carried out, showing a 38% increase in roll control authority and 3.7 times greater control derivatives compared to conventional ailerons. The solid state PBP actuator in the morphing wing reduced the part count from 56 down to only 6, with respect to a conventional servoactuated aileron wing. Furthermore, power was reduced from 24 W to 100 mW, current draw was cut from 5 A to 1.4 mA, and the actuator weight increment dropped dramatically from 59 g down to 3 g.

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“…Another approach on this issue is presented by Barrett et al. 3 where smart bimorph beams are performing in the non-linear domain and particularly in the post-buckling area. The result is increased performance concerning actuation displacement.…”

Section: Introductionmentioning

confidence: 99%

High displacement non-linear asymmetrically designed piezoelectric actuators

Giannopoulos

Monreal

Vantomme

2006

Smart Structures and Materials 2006: Modeling, Signal Processing, and Control

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Non-linear smart actuators have attracted lately the interest of many researchers. It is well known that linear smart actuators have been used in a vast number of applications in different disciplines. However, most of the times a trade off between displacement and force must take place in order to increase their operational envelope. Taking into account this, it is not strange that research is headed towards non-linear mechanics in order to increase displacement, as well as force actuation in smart actuators. In the present work, issues related with the non-linear response of smart beams as well as snap-through performance are investigated. Beams with aluminum cores are equipped with continuous piezoelectric layers that cover only a certain part of the structure. A number of symmetrical and asymmetrical actuators have been realized with different core lengths and thus the amount of active material over the whole length of the actuator varies. These actuators were tested in order to evaluate their critical buckling load as well as their snap-through performance. The snap-through displacement was examined with respect to the post-buckling compression of the actuators for all the configurations and the difference between symmetrical and asymmetrical actuators raises a number of issues concerning the design of such actuators.

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Post-buckled precompressed (PBP) elements: a new class of flight control actuators enhancing high-speed autonomous VTOL MAVs

Cited by 16 publications

References 9 publications

Thermal, electrical, mechanical coupled mechanics for initial buckling analysis of smart plates and beams using discrete layer kinematics

Thermal, electrical, mechanical coupled mechanics for initial buckling analysis of smart plates and beams using discrete layer kinematics

Post-buckled precompressed elements: a new class of control actuators for morphing wing UAVs

High displacement non-linear asymmetrically designed piezoelectric actuators

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