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In the last years the number of electronic controllers of vehicle dynamics applied to chassis components has increased dramatically. They use lookup table of the primary order vehicle global parameters as yaw rate, lateral acceleration, steering angle, car velocity, that define the ideal behavior of the vehicle. They are usually based on PID controllers which compare the actual behavior of every measured real vehicle data to the desired behavior, from look up table. The controller attempts to keep the measured quantities the same as the tabled quantities by using ESP, TC (brakes and throttle), CDC (control shocks absorbers), EDIFF(active differential) and 4WS (rear wheels active toe). The performances of these controls are good but not perfect. The improvement can be achieved by replacement of the lookup tables with a fast vehicle model running in parallel to the real vehicle.

The challenge to design the rear suspension of a rear wheel drive sports car has always been one of optimizing the position of both wheels and therefore the contact patch of the tires in order to obtain the maximum possible limit acceleration. This project takes the active kinematics idea a step further, and for the first time, we present an active system which allows complete control of the wheel by controlling the toe and camber angles on the fly. This allows a more complete control of the contact patch condition which can then further optimize the overall dynamics of the vehicle. This system, called Active Kinematics Suspension (AKS), is realized by four electromechanical actuators (two per side) in a sophisticated multilink axle. This allows direct manipulation of the camber and toe angles of the rear wheels by changing the length of two of the links.

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.

An electromechanical actuator is presented for the active control of a sports car's rear axle kinematics with a high performance-to-size ratio not available on the market up to now. Toe and camber values of both rear wheels are controlled independently to reach the optimum position of the tire contact patch on the ground for each driving situation. The complete system utilizes 4 actuators and is known as Active Kinematics Suspension (AKS). The actuators substitute the camber and toe links in a multilink suspension, without major modifications, on the prototype of an existing car. The actuators are capable of covering the high axial forces seen in the links and can rapidly alter the wheel position. The heart of the actuator is a hollow-shaft brushless DC motor running efficiently in field control. It drives a recirculating ball-screw which transfers the motor's rotational motion to a translational displacement of a central rod.