Since MMM deals with steadystate operating conditions there is no need for a
timebased integration procedure. However, there is a need for a procedure
whereby the vehicle can attain a steadystate solution in all respects. The
condition of "constrained equilibrium" is attained in the simulation by means
of multiple iteration procedures.
Of the six body degrees of freedom only three can be constrained if the tire
loads (and hence forces) are to correspond to those experienced in operation.
Vertical heave motion, roll and pitchwhich produce proper tire loads
including lateral and longitudinal load transfersmust be unconstrained. The
lateral, longitudinal and angular yaw degreesoffreedom are constrained for
the purpose of calculating the unbalanced forces and moments  the inertial
reactions to the tire forces
There are two fundamental MMM solutiontypes. These are often referred to by the
ForceMoment Diagram produced: CNAY or CNCY. These are described briefly
below:
CNAY (Normalized Yawing Moment vs. Lateral Acceleration)

All lateral force assigned to producing lateral acceleration

Constant Speed

Similar to proving ground Constant Throttle test

AY axis of Moment Method diagram also indicates path radius or path curvature

Wheel Torque Options:

FWD, RWD, 4WD

Road Load Torque

Constant Torque, nonRoad Load (accelerating/braking)

Constant Acceleration (varying torque)

Constant Deceleration (varying braking torque)

These metrics can be determined from the CNAY diagram:

Stability Index

Understeer Gradient

Steering Sensitivity

Limit Over/Understeer

Maximum SteadyState Lateral Acceleration

Maximum Lateral Acceleration

Control Moment Gain
CNCY (Normalized Yawing Moment vs. Lateral Force)

Lateral force unassigned or assigned to increasing speed on a constant radius

Constant Radius

Similar to proving ground Constant Radius test

Speed varies across Moment Method diagram

Wheel Torque Options:

Road Load Torque

Constant Torque, nonRoad Load

Constant Acceleration (varying torque)

Constant Deceleration (varying braking torque)

Special case: Infinite Radius

Fundamental presentation of vehicle force/moment characteristics

No path curvature effects
Furthermore, the Moment Method Diagrams can be used for approximate transient
calculations. They have also proven themselves as an excellent tool for trim
change analysis.
MMM TOUR
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