An SPMM measures kinematics and compliance: fundamental suspension characteristics.
"Suspensions have become more complex in order to get the right combination of ride and refinement and handling, which is always a challenge--that's exactly where you need an SPMM," says Best.
An SPMM measures parameters: there's the same number of those irrespective of the number of bushes and suspension arms.
An SPMM takes around five hours but it has been done in half that.
Best refers to his new generation SPMM as a dynamic kinematics and compliance machine--but it's only dynamic to the extent that it gives good results at 2Hz.
A recent development is a converter, allowing SPMM data to be exported directly into the CarSim multibody vehicle dynamic modelling tool.
"Once you've got the right tyre characteristics, and inertial characteristics, which we can also measure on the SPMM, you can start dynamic modelling of the whole vehicle and see how it behaves doing a certain manoeuvre.
"That's closing the loop--going right around a doing a digital model of the whole vehicle but using the parameters as measured by the SPMM," says Best.
In operation, the SPMM subjects the suspension and steering of a vehicle to a variety of forces and displacements, and measures the effects.
Electro-mechanically operated, fully automated and computer controlled, the SPMM is capable of completing a full suite of suspension and steering measurements in less than a day.
The SPMM records the wheel displacements and forces and moments occurring at the tyre to road interface, caused by bounce, roll and pitch of the vehicle body and also by the application of simulated cornering, braking and traction forces.