Vehicle Dynamics Simulation to Develop an Active Roll Control System

Active Roll Control (ARC) is one of the most promising active systems to improve vehicle comfort and handling. This paper describes the simulation based procedure adopted to conceive a double-channel Active Roll Control system, characterized by the hydraulic actuation of the stabilizer bars of a sedan. The first part of the paper presents the vehicle model adopted for this activity. It is Base Model Simulator (BMS), the 14 Degrees-of-Freedom vehicle model by Politecnico di Torino. It was validated through road tests. Then the paper describes the development of the control algorithm adopted to improve the roll dynamics of the vehicle. The implemented control algorithm is characterized by a first subsystem, capable of obtaining the desired values of body roll angle as a function of lateral acceleration during semi-stationary maneuvers. Vehicle simulation is fundamental to verify the performance of the algorithm not only in semi-stationary conditions, but also during extreme dynamic maneuvers, like single and double lane change or single and double step steer. Vehicle dynamics simulation helps the development of a control algorithm to compensate vehicle body dynamics also during these extreme maneuvers, without oscillations. Active Roll Control can be adopted to improve handling by varying the distribution between the anti-roll torques generated by front and rear stabilizer bars. In first approximation, this effect on lateral dynamics is not coupled with the improvement of roll dynamics, since it can be obtained by maintaining the same total value of anti-roll torque, which is the key parameter to control roll dynamics. The paper describes the yaw rate feedback control algorithm and the body sideslip angle control algorithm conceived during this activity. A Luenberger observer is adopted for body sideslip angle estimation. The last part of the paper deals with the Hardware-In-the-Loop test bench which was implemented to test the link between the control algorithm of the Active Roll Control system and the hydraulic hardware of the designed ARC.