Intelligent Control Strategies for Three Degree of Freedom Active Suspension System

Abstract

Suspension system plays a major role in both comfort and stability of a vehicle. This paper presents modeling and controlling for a 3 Degree of Freedom (DOF) active suspension system. Four controllers are designed to control the response of the active suspension system, namely PID, LQR, Fuzzy Logic Controller (FLC) and Artificial Neural Network (ANN). The response for both the active suspension system and the passive suspension system is compared. For passive suspension system, it has been found out that it is hard to improve both passenger comfort and road handling at the same time, because of the fixed parameters that cannot be changed during the work. On the other hand, in active suspension system, both ride comfort and road handling can be improved. This work has showed that ANN, FLC, LQR, and PID controllers can be used with an active suspension system in order to improve the performance, the stability, and the ride comfortability compared to the passive suspension system. All these controllers are simulated using MATLAB and Simulink. Different road profiles are used to test the active suspension system response, such as a step input of 0.1 m, and a sinewave of amplitude of 0.3m and a frequency of 0.318Hz. All the controllers show better response compared to passive suspension system. A compromise can be done to choose the controller depending on the desired states.