To optimize the tyre contact patch in a sports car, Ferrari has developed an active camber and toe (ACT) system comprising of 4 actuators for the rear axle. This complex and completely new system is difficult to model accurately and for this reason, it was decided to combine a physical prototype with a full vehicle model to carry out the functional tests. The method of combining a virtual model with a physical test is known as hybrid simulation.
This functional testing of both the actuators and the vehicle dynamics logic will be performed on an MTS 6DOF bench test prior to physical track testing on a prototype vehicle using Ferrari facility in Maranello, Italy. In support of this functional testing, we will use hybrid simulation techniques with software and methods specifically developed. The planned hybrid test system described in the paper will allow dynamic coupling between the physical bench test and a modified full vehicle simulation model.
The full vehicle model provides the desired dynamic wheel center forces and parameters for the ACT position logic (which is implemented in a rapid prototyping ECU) to the bench test. The physical system responds, and the real displacement of the ACT system is read back into the full vehicle model to calculate the new wheel position, vehicle reaction and the resulting wheel center forces and moments.
This new ACT hybrid simulation implementation will allow testing of the system performance up to frequencies of 40 Hz as well as verification of the logic and safety systems.
