Forward flight response of the active twist rotor for helicopter vibration reduction

Dynamic characteristics of active twist rotor (ATR) blades during forward flight is investigated analytically in this paper. An aeroelastic model for an active rotor system is developed to identify dynamic characteristics of ATR blades with integral strain actuators embedded in their composite construction. More specifically, a time domain integration scheme for the geometrically exact formulation of passive beams is extended with the active materials constitutive relations for the forward flight analysis of the ATR system. In parallel, forward flight wind-tunnel tests are conducted at NASA Langley to collect control sensitivity functions experimentally using dynamically-scaled four-active-bladed rotor system. Preliminary results from the present analytical model are presented and compare well with experimental observations. The theoretical model will be used as a design and evaluation tool for closed-loop controller for twist actuation of the ATR system.

[1]  Carlos E. S. Cesnik,et al.  On the modeling of integrally actuated helicopter blades , 2001 .

[2]  Carlos E. S. Cesnik,et al.  Vibratory loads reduction testing of the NASA/Army/MIT active twist rotor , 2001 .

[3]  Carlos E. S. Cesnik,et al.  Active composite beam cross-sectional modeling - Stiffness and active force constants , 1999 .

[4]  Heli Div.,et al.  Rotor Design Using Smart Materials to Actively Twist Blades , 1996 .

[5]  D. Hodges.  A mixed variational formulation based on exact intrinsic equations for dynamics of moving beams , 1990 .

[6]  Carlos E. S. Cesnik,et al.  Modeling, design, and testing of the NASA/Army/MIT active twist rotor prototype blade , 1999 .

[7]  C. E. Hammond,et al.  A Unified Approach to the Optimal Design of Adaptive and Gain Scheduled Controllers to Achieve Minimum Helicopter Rotor Vibration , 1981 .

[8]  SangJoon Shin,et al.  Design, manufacturing, and testing of an active twist rotor , 1999 .

[9]  Carlos E. S. Cesnik,et al.  HOVER TESTING OF THE NASA/ARMY/MIT ACTIVE TWIST ROTOR PROTOTYPE BLADE , 2000 .

[10]  Donizeti de Andrade,et al.  Application of finite-state inflow to flap-lag-torsion damping in hover , 1992 .

[11]  Khanh Nguyen,et al.  Full-Scale Demonstration of Higher Harmonic Control for Noise and Vibration Reduction on the XV-15 Rotor , 2000 .

[12]  Robert G. Loewy,et al.  REVIEW ARTICLE: Recent developments in smart structures with aeronautical applications , 1997 .

[13]  Matthew L. Wilbur,et al.  Dynamic response of active twist rotor blades , 2000 .

[14]  Richard L. Bielawa,et al.  Rotary wing structural dynamics and aeroelasticity , 1992 .

[15]  O. Bauchau.  Computational Schemes for Flexible, Nonlinear Multi-Body Systems , 1998 .

[16]  Nesbitt W. Hagood,et al.  Material characterization of Active Fiber Composite actuators for active twist helicopter rotor blade applications , 2000 .

[17]  Edwin W. Aiken,et al.  Simulator Investigation of Side‐Stick Controller/Stability and Control Augmentation Systems for Helicopter Visual Flight , 1985 .

[18]  Hughes Helicopters,et al.  On Developing and Flight Testing a Higher Harmonic Control System , 1983 .

[19]  Inderjit Chopra,et al.  Hover Testing of Smart Rotor with Induced-Strain Actuation of Blade Twist , 1997 .

[20]  Richard S. Teal,et al.  Higher Harmonic Control: Wind Tunnel Demonstration of Fully Effective Vibratory Hub Force Suppression , 1985 .

[21]  John P. Rodgers,et al.  Development of an integral twist-actuated rotor blade for individual blade control , 1999 .

[22]  David A. Peters,et al.  Finite state induced flow models. II - Three-dimensional rotor disk , 1995 .

[23]  Norman D. Ham,et al.  Helicopter individual-blade-control research at MIT 1977-1985 , 1986 .

[24]  Wilkie W. Keats,et al.  Aeroelastic Analysis of the NASA/ARMY/MIT Active Twist Rotor , 1999 .

[25]  Victor Giurgiutiu,et al.  RECENT ADVANCES IN SMART-MATERIAL ROTOR CONTROL ACTUATION. , 2000 .