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 handling.

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 acquired.

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 simulation.

MRA has pioneered Moment Method technology and continues to develop new analysis techniques. Follow the links below to take a tour of MMM.

MMM TOUR

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MMM Home | Background | Input | Solution | Output