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

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.