Active Vibration Control Of Cable-strut Tensegrity Structures Under Wind Excitation

Cable-strut tensegriy structures are likely to present significant displacements and vibrations under dynamic wind loads.In order to eliminate or at least minimize the undesirable effects of this perturbation,the theory of active control is introduced. Considering geometric nonlinearity and the effect of wind-structure interaction,the active control formula is established based on the instantaneous optimal control algorithm.The precise time-integration method is employed to solve the nonlinear dynamic formula and a Matlab program is produced to realize the process.In order to obtain the wind velocity sample,two artificial wind simulation methods,the wave superposition method and autoregressive representation,are described in this paper and a Matlab program is developed.To demonstrate the efficiency of the theory,it is applied to a trigonal prism tensegrity cell which is subjected to dynamic wind loads.Comparisons of the responses of controlled and uncontrolled structures verify the efficiency of this theory.A Levy cable dome is introduced to investigate the validity of active control on tensegrity structures and the structural responses controlled and uncontrolled are compared.The control of structural displacements along different axises presents different performances.The distribution of active control force and its magnitude are studied.With respect to the internal force of the cable,such control may generate a decrease or an increase according to the variation of cable force.In the remaining part of this paper,the importance of the weight matrices of Q₁,Q₂ and R is analysed and the results reveal that Q₁ plays a determinant role in the process of active control.Besides,the control effect varies with the actuator layout and number,and an optimal actuator layout is recommended.Summarily,the results indicate that the active control theory presented in this paper is suitable to tensegrity structures under dynamic wind excitation.