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RISS 인기검색어
- 검색키워드
- 저자 : Carlos E. S. Cesnik (검색결과 2 건)
- 무료
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Helicopter Vibration Reduction in Forward Flight Using Blade Integral Twist Actuation
SangJoon Shin,Carlos E. S. Cesnik 대한기계학회 2007 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.21 No.2
An analytical framework has been developed to examine integrally-twisted helicopter blades and their aero elastic behavior during forward flight. This is accomplished by modifying an existing multi-body dynamics code, DYMORE, with active material constitutive relations. An integral twist-actuated rotor blade was designed within this framework. A four-bladed fullyarticulated active rotor system was built and tested to demonstrate the present concept in forward flight. The impact of integral twist actuation on fixed and rotating system loads during forward flight is evaluated by the proposed analysis. While discrepancies are found in the amplitude of the loads under actuation, the predicted trend of load variation with respect to its control phase correlates well with the experiments. Factors affecting the accuracy of the present analysis against the experimental results are described in detail. Based on the present discussion, an improved analysis is planned to be conducted.
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Design and Simulation of Integral Twist Control for Helicopter Vibration Reduction
Sangjoon Shin,Carlos E. S. Cesnik,Steven R. Hall 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.1
Closed-loop active twist control of integral helicopter rotor blades is investigated in this paper for reducing hub vibration induced in forward flight. A four-bladed fully articulated integral twist-actuated rotor system has been designed and tested successfully in wind tunnel in open-loop actuation. The integral twist deformation of the blades is generated using active fiber composite actuators embedded in the composite blade construction. An analytical framework is developed to examine integrally twisted helicopter blades and their aeroelastic behavior during different flight conditions. This aeroelastic model stems from a three-dimensional electroelastic beam formulation with geometrical-exactness, and is coupled with finite-state dynamic inflow aerodynamics. A system identification methodology that assumes a linear periodic system is adopted to estimate the harmonic transfer function of the rotor system. A vibration minimizing controller is designed based on this result, which implements a classical disturbance rejection algorithm with some modifications. Using the established analytical framework, the closed-loop controller is numerically simulated and the hub vibratory load reduction capability is demonstrated.
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