An interval type-2 fuzzy logic controller for quarter-vehicle active suspensions

Abstract

A novel adaptive fuzzy logic controller (AFC) based on an interval type-2 fuzzy controller is proposed for vehicle non-linear active suspension systems. The adaptive strategy elicited from the least-mean-squares optimal algorithm is adopted to self-tune lower bounds and upper bounds of interval type-2 fuzzy membership functions (IMF2s). The IMF2s are utilized in the AFC design to deal with not only non-linearity and uncertainty caused by irregular road inputs and immeasurable disturbance, but also the potential uncertainty of experts knowledge and experience. A case study based on a quarter-vehicle active suspension model has demonstrated that the proposed type-2 controller significantly outperforms conventional fuzzy controllers of an active suspension and a passive suspension.