Advance the Efficiency of an Active Suspension System by the Sliding Mode Control Algorithm With Five State Variables

Roughness on the road is the main cause of the oscillation when the vehicle travels. The suspension system plays a role in maintaining the stability of the vehicle in fluctuating states. To improve comfort and smoothness, the active suspension system is used to replace the conventional passive suspension system. The performance of the active suspension system depends on the pre-designed controller. Linear control algorithms cannot guarantee oscillation requirements in all cases. Therefore, the use of a nonlinear control method is necessary. In this paper, the SMC (Sliding Mode Control) algorithm is proposed to control the operation of the active suspension system. To optimize this algorithm, five state variables were considered. Besides, the output signal of the model has been considered by the fifth derivative, and the error signal is also considered the fourth derivative. This is a completely novel and unique method. The simulation is done in the MATLAB-Simulink environment. According to this result, the displacement and acceleration of the sprung mass was significantly reduced when the vehicle used the active suspension system controlled by the SMC algorithm. These values only reach 14.4% and 14.1% compared to the case of the vehicle using the mechanical suspension system. The effect of the SMC algorithm is extremely positive. This will be the basis for developing more complex control algorithms in the future.