Optimal design of hedge-algebras–based controller for vibration control of vehicle suspension systems

This study aims to investigate an optimal design problem for vibration control of vehicle suspension models for reducing dynamic responses of the systems. The controller is constructed and optimized based on the approach of the hedge-algebras theory. Optimized parameters include fuzziness measures and reference ranges of state and control variables. Objective functions are considered to minimize the car body vibration and other essential objectives. Initial and optimized controllers have validated their stability through a newly proposed method using rule surfaces of the hedge-algebras–based controller. The controllers based on hedge-algebras theory have higher performance than controllers in previous publications and ensure the system stability and robustness to changes in the car body and wheel masses. The optimal approach in the present work allows determining values of design variables that are appropriate for the controlled models instead of using a trial–error method to evaluate these variables. In addition, the proposed approach to test the system stability allows simplifying this task for controllers using hedge-algebras theory.