The Multimatic TrueActive™ Spool Valve (TASV) Damper system is debuting on the Ferrari Purosangue; the automaker’s latest vehicle and first to feature the innovative Ferrari Active Suspension Technology (F.A.S.T.) system enabled by Multimatic TASV technology.
The Multimatic TASV system is the first production active suspension in the world to integrate an electric motor with spool valve damping to supplement vehicle springs with parallel force actuation through the damper. This eliminates the need for any anti-roll devices and additional mechanisms for dynamic ride height and rate adjustment. It can also control vehicle wheel motions with more authority and at higher frequencies than adaptive or semi-active suspension systems.
This solution means the virtual lower kingpin attachment point created by the two arms is very close to the wheel centre, thereby drastically reducing the scrub radius, i.e. the distance between the point of intersection of the extension of the kingpin axis and the centre of the tyre contact patch at ground level. This makes the steering wheel less sensitive to road irregularities and braking.
One advantage of Ferrari’s active suspension system is the speed at which the TASV 48-volt motor actuators apply force in the direction of the damper’s stroke. The high-power density, three-phase brushless electric motor was co-developed for this application by Ferrari. The motor uses “slotless” stator winding technology to minimize radial dimensions and maximize power density. From a mechanical point of view, the motor force is transmitted in a novel way via a twin-lead ball screw connected directly to the hydraulic damper piston rod which enables high-frequency response and reduces friction, inertia and package space.
The active suspension system uses accelerometers and position sensors on each suspension corner and interfaces with the Side Slip Control (SSC) 8.0 and the 6w-CDS sensor. Ferrari’s proprietary control logic, together with the TASV dampers supplied by Multimatic, electronically manages every performance element of the fully active suspension system.
This technology optimises maximum cornering performance thanks to the variable and continual distribution of roll stiffness and the actively lowered roll centre (reduced by up to 10mm), to the benefit of the side force acting on the tyres and the balance between over and understeer. The high-frequency control regulates both body motion and wheel movement, thus reducing roll and pitch as well as absorbing road surface irregularities.
