Development of a control strategy for road vehicles with semi-active suspensions using a full vehicle ride model


Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Graduate School of Natural and Applied Sciences, Graduate School of Natural and Applied Sciences, Turkey

Approval Date: 2009

Student: ZEYNEP ERDOĞAN

Supervisor: YAVUZ SAMİM ÜNLÜSOY

Abstract:

The main motivation of this study is the design of a control strategy for semi-active vehicle suspension systems to improve ride comfort for road vehicles. In order to achieve this objective, firstly the damping characteristics of Magnetorheological dampers will be reviewed. Then an appropriate semi-active control strategy manipulating the inputs of the dampers to create suitable damping forces will be designed. Linear Quadratic Regulator (LQR) control strategy is the primary focus area on semi-active control throughout this study. Further, skyhook controllers are examined and compared with optimal LQR controllers. The semi-active controller is tuned using a linearized full (4 wheel) vehicle ride model with seven degrees of freedom. Some selected simulations are carried out by using a nonlinear model to tune LQR controller in an effort to optimize bounce, pitch, and roll motion of the vehicle. Time domain simulations and frequency response analysis are used to justify the effectiveness of the proposed LQR control strategy.