Designing a Switched Takagi-Sugeno Fuzzy controller for CDC semi-active suspensions with current input constraint

To prevent the degradation of control performance resulting from the use of the clipped approach, this paper presents a novel control strategy for CDC (continuous damping control) semi-active suspensions using the Takagi-Sugeno (T-S) fuzzy method based on a piecewise affine (PWA) vertical dynamics model. First, to account for the significant tension-compression asymmetry and dissipative constraint of CDC damper force, a piecewise damping-force model is developed with current serving as input. Due to the nonlinear terms, T-S fuzzy system is then utilized to describe the suspension system via the sector nonlinearity approach. Finally, a fuzzy state feedback controller considering the asymmetry saturation of the control current is designed for the obtained switched T–S fuzzy model with optimized H∞ performance for suspension system by using the parallel distributed compensation (PDC) scheme. Simulation and experimental results under sinusoidal, random and transient excitations show significant improvements of the proposed approach on ride comfort and road handling while guaranteeing the performance under the input current constraint.