Fuzzy Robust Control of Nonlinear Time-Delay Active Suspension Systems with Limited Frequency Band

This paper proposes a finite frequency
$H_{\infty}$
control algorithm for time-delay active suspension systems based on Takagi-Sugeno (T-S) fuzzy model. First of all, to better investigate suspension dynamics, a typical quarter-car active suspension model with varying masses and actuator time-delay is established for control analysis and design base on a set of T-S fuzzy rules. Then, considering that the human body is much more sensitive to vertical vibrations of 4–8 Hz, a finite frequency performance criterion is presented as the guidance for control design. Meanwhile, other mechanical constraints such as suspension travel and tire dynamic deflection are also considered to guarantee the dynamic stability of suspension systems. Finally, this algorithm is implemented on a quarter suspension test rig. Experimental results show that the proposed approach is more effective to improve suspension body acceleration performances while the robustness and stability of the systems are maintained simultaneously.