Comparison of Control Methods for Half-Car Active Suspension System

Suspension systems are of great importance in ensuring stable driving in vehicles and the appropriate reaction of vehicle sub-elements against disturbing inputs. Active suspension systems react quickly to road and driving conditions and positively affect vehicle dynamics and passenger comfort. The main factor in improving active suspension systems' performance is determining the suitable control method against the determined disturbing inputs. This study aims to contribute to the development of vehicle suspension technology by investigating the potential of optimizing the performance of active suspension systems with different control algorithms. In the study, a half-car model with an active suspension system was simulated on three different road profiles: bump-pit, sinusoidal, and ISO-8608. Fuzzy logic, PID, Fuzzy-PID, and MPC control methods are used to control the active suspension system, and their advantages over each other and the passive suspension system are investigated. The effectiveness of the control methods determined on each road profile has been analyzed in the evaluations made regarding vehicle dynamics and passenger comfort. As a result of the study, it is observed that the MPC control algorithm was able to control the active suspension system stably and quickly on all three road profiles with a high success rate. The best results are obtained by the MPC algorithm for bump pit, sinusoidal, and ISO8608 road profiles, and the RMSE values for each road profile are 1.466, 0.047, and 0.449, respectively. The suitable control method minimized vehicle body displacement and pitch angle and improved vehicle stability. In the passenger comfort evaluation, 33.49%, 47.79%, and 12.26% improvements were obtained using the MPC control method on bump-pit, sinusoidal, and ISO-8608 road profiles, respectively.