Stall nonlinear aeroelastic effects and active control of thin-walled composite blade with piezoelectric patches embedded

Abstract

Stall nonlinear flutter behavior and active control of anisotropic composite blade have been investigated based on piezoelectric actuation. The blade body comprises an elliptical composite host structure and a lightweight honeycomb skin structure. The composite blade with elliptical section is modeled as a thin-walled beam structure with circumferential asymmetric stiffness (CAS) configuration, exhibiting transverse shear deformation, warping restraint effect, and vertical bending, with structural tailoring implemented. The stall-induced flutter suppression and nonlinear aeroelastic effects of linearized dynamic response characteristics of blade incorporating stall nonlinear aerodynamic model are investigated. The nonlinear aeroelastic coupled equations are reduced to ordinary equations by the Galerkin method, with the aerodynamic force decomposed by strip theory. Active feedback control based on boundary moment control strategy is developed to enhance the vibrational behavior and dynamic response to aerodynamic excitation and stabilize structures that might be damaged in the absence of control. Various active feedback control schemes tuned by optimal proportional-derivative (PD) controller are implemented. The excellent control effect is not only confirmed by the time response with its vibration amplitude greatly suppressed but also confirmed by the frequency change and comparison. The research provides a way for rare study of amplitude suppression of stall nonlinear aeroelastic effect of thin-walled composite blade with CAS configuration and piezoelectric patches embedded.

PD-Based Iterative Learning Control for the Nonlinear Low-Speed-Jitter Vibration of a Wind Turbine in Yaw Motion

“…At the same time, the auxiliary motor driving method proposed in this design increased the driving torque from 10% to 30% or even higher (in the present study, it was only set at 20% and directly affected the LSJ system), which meant a better control performance and disturbance resistance. It can not only be applied to the control process of a single wind turbine, for resisting various types of flutter [1][2][3][4], but can also be used in the control processes of wake and eddy-current [5,6] disturbances in wind farm clusters.…”

“…This coupling of low-speed and low-frequency vibrations has a catastrophic impact on the operation of the unit. The design in the present study focused on the low-speed buffeting during the yaw process, and treated the load excitation in the related references [1][2][3][4][5][6][11][12][13][14][15][16][17][18][19] as a dynamic disturbance, thus achieving stability control. Based on the proposed iterative algorithm using the openloop PD, further research on the coupling resonance of the impeller tower has a positive significance for reducing the incidence of wind turbine damage accidents.…”

“…Therefore, it is necessary to investigate the fracture failure and vibration issues of large wind turbine blades and towers. The destructive fracture phenomena of megawatt wind turbine blades and towers that have occurred around the world in recent years also indicate the necessity of studying this issue [1,2]. In the past decade, the research on wind turbine blade vibration has generally focused on the problem of the stall-induced nonlinear aeroelastic stability of blades (i.e., stall flutter in coupled vibrations under the combined action of structural nonlinearity and aerodynamic nonlinearity [3], linear classical flutters at high wind speeds [4], and fracture failures caused by vibrations from various turbulence and wake effects) [5].…”

“…On the basis of this model, the nonlinear mathematical model of the LSJ system is constructed. Inspired by the dual-driven parallel control mechanism of pitch and yaw servos [2], based on the conventional lead gear of yaw driving, the auxiliary gear of yaw driving is designed and mounted. Based on the openloop PD control and the iterative learning control methods of the time-varying continuous system, the stability control and jitter suppression of the yaw system are realized by using the combined driving torques provided by the lead and auxiliary gears.…”