Proposing an original control algorithm for the active suspension system to improve vehicle vibration: Adaptive fuzzy sliding mode proportional-integral-derivative tuned by the fuzzy (AFSPIDF)

Stimulation from the road surface can cause vehicle vibrations. Vehicle vibration is evaluated based on the change of displacement and acceleration values of the vehicle body. In order to improve ride comfort, an active suspension system should be used. This article proposes a new method for controlling the functioning of the active suspension system. The AFSPIDF algorithm was designed based on PID, SMC, and Fuzzy algorithms. The PID algorithm is only applicable to SISO objects with linear oscillations. The SMC algorithm can be applied to nonlinear systems; however, a chattering phenomenon can still occur. Meanwhile, a Fuzzy algorithm can increase the flexibility of control states. Therefore, combining all three of these algorithms is necessary to become a new integrated control algorithm. The input signal of the Fuzzy algorithm is the output signal of the SMC algorithm. Besides, the PID controller parameters are also adjusted by another Fuzzy algorithm. These two Fuzzy algorithms operate in complete isolation from one another. This is a wholly new and unique algorithm. With two specific cases, the numerical simulation method explores vehicle vibration. In each case, four situations are compared. The results of the simulation process have shown that the values of displacement and acceleration of the vehicle body are significantly reduced once the AFSPIDF algorithm is used. In the first case, these values do not exceed 2.5% compared with vehicles using passive suspension systems. In the second case, these values do not exceed 13.5%. As a consequence, the stability and comfort of the vehicle have been greatly enhanced.