Stochastic Semi-active Control Method of Structure Based on Magnetorheological Dampers Considering Time Delay

Summary

A Stochastic Optimal Semi-active Control method with time delay compensation (SOSC-PSO) is proposed in this paper, which is designed to maintain the reliability of structures controlled by MR dampers. 

Abstract

The use of Magnetorheological (MR) dampers in semi-active control systems faces a key challenge: time delay caused by feedback processes, which reduces the reliability of civil engineering structures under stochastic excitations. This paper proposes a Stochastic Optimal Semi-active Control method with time delay compensation (SOSC-PSO), leveraging the Physical Stochastic Optimal control theory (PSO) to address this issue and maintain structural reliability. The proposed method derives the semi-active control force as a function of both current and previous states, compensating for time delays in the control process. To optimize control effectiveness, key parameters are tuned based on a reliability criterion for the system. Validation analyses on single-degree-of-freedom and multi-degree-of-freedom structures under stochastic seismic excitations show that time delays significantly impair the performance of MR dampers. However, the SOSC-PSO method with time delay compensation significantly improves control effectiveness, and with optimized parameters, it enhances the reliability of the structural control system beyond methods without parameter optimization.  

Introduction

Improving the performance of engineering structures in the face of catastrophic events, such as earthquakes and extreme winds, remains a primary concern within the civil engineering community. Structural control, an effective technique for reducing vibrations, has been proven to enhance both the safety and functionality of such structures^1,2,3. Over the past few decades, various advanced methods and technologies have been developed for this purpose. These methods can be broadly classified into four categories based on the type of energy used to drive the control devices: acti

Protocol

1. Stochastic optimal semi-active control method

As the control effect of an MR damper is significantly influenced by the inevitable time delay, a semi-active control method with a time delay compensation algorithm is developed to increase the performance of the controlled structure. Besides, the randomness inherent in external excitations causes the obvious uncertainties of dynamic responses. The PSO control is introduced to optimize the critical parameters of the proposed method for ensuring the reliability of structure control system.

1.1 Compensation algorithm of semi-active control

Results

Aiming at the influence of time delay on the control effectiveness of the MR damper-based method, a semi-active control method with time delay compensation is proposed in this paper. In the proposed method, the critical parameters are optimized based on the reliability criterion. By comparing the control effectiveness, the following conclusions are addressed:

(1) The semi-active control method based on an MR damper is more robust than the active control method. Even with time delay, semi-activ...

Discussion

With the introduction of the Physical Stochastic Optimal control theory (PSO), a Stochastic Optimal Semi-active Control method with time delay compensation (SOSC-PSO) is proposed in this paper, which is designed to maintain the reliability of structures controlled by MR dampers. To compensate for the time delay in the proposed method, the semi-active control force is derived as the function of not only the present states but also the states and control forces in previous time steps in discrete state space. To achieve the...

Materials

Name	Company	Catalog Number	Comments
MATLAB	MathWorks	2016	Using for the calculation of the proposed method