Study On Decentralized Control For Engineering Structure System With Multiple Time-Delays Compensation

Building structures with active and semi-active control system can effectively reduce their vibration responses under the external excitation,which make sure the controlled structure enough safety and comfort.The traditional control strategies are mostly focused on centralized control,which has only one controller in the whole system.In the centralized control system,sensors in each part of the structure collect the structure response information and transfer it to the controller,then,the controller makes dynamic optimization decisions after receiving the information and deliver control instruction to the actuators to realize the active control for structure.However,for super high-rise and large span complicated structure,centralized control system is difficult to meet the stability,reliability and easy maintenance requirements.Because of the limitations of centralized control,several decentralized control strategies for engineering structure is presented in this paper.Considering that each subsystem of the decentralized control system may produce different time-delay,this paper present several adaptive time-delay compensation methods for decentralized control systems with multiple time-delays.The main research of this paper is generalized as follows:1)Two kinds of decentralized control strategies based on LQG control algorithm are proposed,which are local optimal decentralized control and global optimal decentralized control respectively according to the structure response information that subsystem acquires.If the subsystem only obtain substructure its own response information,the optimal control force is calculated by the local information,named local optimal decentralized control.If the subsystem obtain all the information of the structure,the optimal control force is calculated by the global information named global optimal control.On the basis of instantaneous optimal control,the instantaneous optimal decentralized control is presented,which can realize decentralized control of structure vibration only need to obtain the response information ofsubstructure itself and the response information of the top floor of its lower substructure.The weight coefficient of each control strategy is acquired through the Invasive Weed Optimization(IWO)algorithm.The simulation of 9-storey Benchmark steel structure model designed by ASCE is conducted to demonstrate the validity of the above decentralized control strategies,the results show that all the decentralized control strategies have certain control performance.Among them,the performance of global optimal decentralized control and instantaneous optimal decentralized control are similar and they are better than the local optimal decentralized control and overlapping decentralized control,while the overlapping decentralized control is better than the local optimal decentralized control..2)In view of the problem that the subsystems of decentralized control system have multiple time-delays,three kinds of time delay compensation methods are proposed,which are recursive response method,IWO gain matrix optimization method and the instantaneous optimal time-delay compensation method respectively.9-storey Benchmark model of the steel structure is also used as the simulation example.The result indicates that all the time delay compensation methods are effective not only when subsystems have different absolute time-delays but also when different relative time-delays exists among subsystems.3)Mechanics performance testing is proceed to the RDL005 MR damper to confirm its hysteretic behavior with different current input and different frequency of external excitation.A parameter identification method based on IWO algorithm is presented to determine the mechanical model parameters of the MR damper.Comparing with the parameters acquired by least squares method,the result proved that IWO algorithm is a reliable method for parameter identification.Combining clipped-optimal algorithm with LQG global optimal decentralized control strategy,this paper presents a kind of semi-active decentralized control strategy.Considering that multiple time-delays would also exists in semi-active decentralized control system,the recursive response method of time-delay compensation is designed for the semi-active delay system.Numerical simulation is conducted to a 7-storey steel-frame structure model.The result indicates that the proposed semi-active control strategy has good control performance,and it also shows that the recursive response method has good effect of time-delay compensation in semi-active control system with time-delay.