A series of challenges in vehicle dynamics design and produced by Bill Cobb for the Vehicle Dynamics Professionals' Facebook group.

The challenges focus on treatment of standardized vehicle dynamics tests. The challenges make extensive use of the cornering compliance concept.

The challenges were posted on the Vehicle Dynamics Professionals's Facebook group over the course of July 11-12th, 2024.

The simulation data for each challenge is provided in the data folder.

From a constant steer, variable speed understeer gradient test, show a plot of the understeer function vs. lateral acceleration showing the understeer gradient at a lateral acceleration of 0.15 G.

The challenge data is available in data/marc1.txt.

From an on-centre chirp steer test at constant speed, show a Bode plot of the yaw velocity by steer response and compute the following metrics.

• Understeer gradient
• Steady-state gain
• Peak gain
• Frequency at peak gain
• Ratio of peak to steady-state gain
• Bandwidth

As an additional challenge, show a Bode plot of the yaw moment by steer response.

The challenge data is available in data/marc2.txt.

From a constant radius understeer gradient test, show a plot of the understeer function and cornering compliances vs. lateral acceleration. Compute the tangent speed of the vehicle under test.

The challenge data is available in data/marc3.txt.

From a constant speed, variable steer gradient test, show a plot of the understeer function and cornering compliances vs. lateral acceleration.

The challenge data is available in data/marc4.txt.

From a constant speed step steer test at varying steering magnitudes, show a plot of the following metrics.

• Understeer function and cornering compliances vs. lateral acceleration
• Step rise time of the steer angle, yaw velocity, chassis slip angle, and lateral acceleration vs. lateral acceleration
• Step settling time of the yaw velocity, chassis slip angle, and lateral acceleration vs. lateral acceleration
• Step overshoot percentage of the yaw velocity, chassis slip angle, and lateral acceleration vs. lateral acceleration

The challenge data is available in data/marc5.csv.

An implementation by @kktse written in Python is available in the python folder. This solution is implemented in a Jupyter notebook and makes use of polars, numpy, scipy, matplotlib and python-control libraries.

Further details can be found in the README.md.

An implementation by Bill Cobb written in MATLAB is available in the matlab folder. These have been uploaded to the repository at the request the author.