ACTIVE-TWIST ROTOR CONTROL APPLICATIONS FOR UAVs

Wilbur, Matthew L.; Wilkie, W. Keats

doi:10.1142/9789812772572_0024

Cited by 12 publications

(8 citation statements)

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“…The ribs had rollers in contact with the skin to allow sliding, and so avoid stiffening the wing. Wilbur and Wilkie (2004) proposed an active twist rotor (ATR) concept with active fiber composites piezocomposite actuators. The concept can reduce vibration and noise, and reduce the rotor power requirements by 23% and improve its performance by 1%.…”

Section: Piezoelectric Actuation Of Twist and Rigid-body Rotationmentioning

confidence: 99%

A Review of Morphing Aircraft

Barbarino

Bilgen

Ajaj

et al. 2011

Journal of Intelligent Material Systems and Structures

1,137

647

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Aircraft wings are a compromise that allows the aircraft to fly at a range of flight conditions, but the performance at each condition is sub-optimal. The ability of a wing surface to change its geometry during flight has interested researchers and designers over the years as this reduces the design compromises required. Morphing is the short form for metamorphose; however, there is neither an exact definition nor an agreement between the researchers about the type or the extent of the geometrical changes necessary to qualify an aircraft for the title ‘shape morphing.’ Geometrical parameters that can be affected by morphing solutions can be categorized into: planform alteration (span, sweep, and chord), out-of-plane transformation (twist, dihedral/gull, and span-wise bending), and airfoil adjustment (camber and thickness). Changing the wing shape or geometry is not new. Historically, morphing solutions always led to penalties in terms of cost, complexity, or weight, although in certain circumstances, these were overcome by system-level benefits. The current trend for highly efficient and ‘green’ aircraft makes such compromises less acceptable, calling for innovative morphing designs able to provide more benefits and fewer drawbacks. Recent developments in ‘smart’ materials may overcome the limitations and enhance the benefits from existing design solutions. The challenge is to design a structure that is capable of withstanding the prescribed loads, but is also able to change its shape: ideally, there should be no distinction between the structure and the actuation system. The blending of morphing and smart structures in an integrated approach requires multi-disciplinary thinking from the early development, which significantly increases the overall complexity, even at the preliminary design stage. Morphing is a promising enabling technology for the future, next-generation aircraft. However, manufacturers and end users are still too skeptical of the benefits to adopt morphing in the near future. Many developed concepts have a technology readiness level that is still very low. The recent explosive growth of satellite services means that UAVs are the technology of choice for many investigations on wing morphing. This article presents a review of the state-of-the-art on morphing aircraft and focuses on structural, shape-changing morphing concepts for both fixed and rotary wings, with particular reference to active systems. Inflatable solutions have been not considered, and skin issues and challenges are not discussed in detail. Although many interesting concepts have been synthesized, few have progressed to wing tunnel testing, and even fewer have flown. Furthermore, any successful wing morphing system must overcome the weight penalty due to the additional actuation systems.

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Section: Piezoelectric Actuation Of Twist and Rigid-body Rotationmentioning

confidence: 99%

A Review of Morphing Aircraft

Barbarino

Bilgen

Ajaj

et al. 2011

Journal of Intelligent Material Systems and Structures

1,137

647

View full text Add to dashboard Cite

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“…These actuators are much more reliable than AFC actuators. Further more the cross sectional design is differing from the rotor blades developed by Boeing/Penn State University/MIT [2,3] and NASA/Army/MIT [6,11]. While those model rotor blades are built with a D-spar the blade developed at DLR has a C-spar design.…”

Section: Atb Conceptmentioning

confidence: 99%

Measurement of twist deflection in active twist rotor

Riemenschneider

Opitz

2011

Aerospace Science and Technology

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“…This allows to overcome the limitations of using only a swashplate as actuator, such as the need to install otherwise over-dimensioned hydraulic actuators and the impossibility to independently control more than three blades. Different methods of actuation have been studied to carry out Individual Blade Control (IBC) (2-5) . In this paper, we assume the availability of actively twisted blades.…”

Section: Introductionmentioning

confidence: 99%

“…Piezoelectric actuators are distributed along the blade span, with the control voltage computed to minimise the aerodynamic loads. This solution has been widely investigated in recent years (6,7) , and experimental tests carried out at NASA (2) and DLR (8,9) proved its feasibility.…”

Section: Introductionmentioning

confidence: 99%

Periodic controllers for vibration reduction using actively twisted blades

2016

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This paper compares two periodic control methods, the optimal H2 and the periodic static output feedback (POF), to reduce the helicopter rotor vibrations. Actively twisted blades with Macro-Fibre Composite (MFC) piezoelectric actuators are used. The design model is based on a simplified aerodynamic model and on a multi-body model of the Bo 105 isolated rotor with the original blades replaced by actively twisted ones. The performance of the two controllers in alleviating hub loads is verified with improved simulations based on a free-wake model

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ACTIVE-TWIST ROTOR CONTROL APPLICATIONS FOR UAVs

Cited by 12 publications

References 0 publications

A Review of Morphing Aircraft

A Review of Morphing Aircraft

Measurement of twist deflection in active twist rotor

Periodic controllers for vibration reduction using actively twisted blades

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