MRA develops and licenses four comprehensive models for vehicle
dynamics analysis. These models are based on a real, physical understanding of
the automobile. They are evolved directly from the pioneering work overseen by
Bill Milliken at Cornell Aeronautical Laboratories and have been continually
developed for 30+ years.
All models are lumped-parameter, nonlinear and large amplitude. They include
detailed kinematic & compliance data, aerodynamics and tire models. With only
small differences, the same input files (containing measurements & descriptions
of the vehicle and tires) are used with all four simulations.
Customers often request specific features which MRA then adds to the computer
model. These features may remain proprietary to that customer for a period of
We emphasize that these programs are not animations. They are complex
engineering calculations based on measured vehicle/tire data and understanding
gained from a long history of research into the science and physics of
automobile vehicle dynamics.
The MRA Nondimensional Tire Model is available
in each of the comprehensive vehicle simulations. This powerful and
mathematically consistent approach to tire data has shown significant
advantages over other tire modeling schemes. Furthermore, MRA has a number of
smaller vehicle simulations and vehicle dynamics utility programs (e.g., a Tire
Data Plotter for graphing tire data from simulation input files). These can be
made available on specific request.
MRA's comprehensive vehicle dynamics programs are:
MRA Moment Method, MMM: A non-linear,
quasi-steady-state analysis that predicts vehicle handling over the full
lateral and longitudinal acceleration range, including limit behavior. MMM has
many parallels to the static analysis of stability and control widely used in
aircraft design. Windows or DOS-box interface. Over 100 engineering vehicle
parameters are output. Postprocessor to generate moment method diagrams,
response plots and friction circle diagrams.
Lap Time Simulation, LTS: Uses a trimmed version
of the MMM static analysis to predict performance on a race track. Determines
overall lap time and over 100 engineering vehicle parameter outputs at up to
2000 locations around the track. Windows or DOS-box interface. Multiple output
formats. Includes track map utility.
Vehicle Dynamics Simulation, VDS: Time-based
simulation used for complete (and partial) non-linear dynamic simulations of
steering, ride and handling characteristics. Ideal for detailed study of
transient maneuvers or particular problem areas (e.g., transient load transfer,
on-center steering). Over 220 engineering vehicle parameters are output.
Vehicle Dynamics for use with MATLAB/Simulink, VDMS:
Similar to VDS, this time-based vehicle simulation is programmed in Simulink
and run through MATLAB. Much of the program code is open to the user for
additions (e.g. to develop control systems). Over 200 engineering vehicle
parameters are output variables. MATLAB GUI plotter. VDMS has been included by
The MathWorks, Inc. in its MATLAB Connections Program.