MMM Tour: HOME
The MRA Moment Method (MMM) is a quasi-static comprehensive vehicle dynamics
simulation which has been under continual use and development since 1969. MMM
is run through either a Windows interface, shown below, or a DOS-box. It
contains extensive post-processing capabilities with which to analyze the data.
Unlike time-based simulations, MMM constructs a portrait of the entire vehicle
maneuvering envelope by setting the vehicle at combinations of vehicle sideslip
angle and steer angle. Constraining D'Alembert forces hold the vehicle in
place--these forces and moments represent the unbalanced forces and moments
available for linearly and angularly accelerating the vehicle. At each sideslip
and steer combination over 100 detailed vehicle outputs are recorded.
The results, viewed using the post-processing utilities, provide information on
vehicle stability and control -- stability index, steering sensitivity,
under/oversteer and roll gradient, among others. The Force-Moment Diagram, the
fundamental program output, provides the long-sought portrait of vehicle
A "Friction Circle" program allows the user to select any point on the
Force-Moment diagram and have a graphical presentation of vehicle state
variables, wheel loads, tire forces and other detailed operating conditions at
the four wheels.
Steady-state data, as would be obtained on a skidpad, is produced, and
non-steady-state data (much more difficult to obtain in the real world) is also
Purchase of a MMM license includes the MMM program, MMP and Friction Circle
post-processors, sample data files, a full day of training at MRA, a 160 page
User's Manual, a 100 page Interpretation Manual and support by MRA. MRA's
intent is to ensure that the purchaser can take full advantage of the
MRA has pioneered Moment Method technology and continues to develop new analysis
techniques. Follow the links below to take a tour of MMM.
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