How to edit 4-Post Rig example suspension geometry?

Hello!

I am editing the example of the 4-post rig test of a sedan-car in order for it to have the same specs as my formula student car suspension. I am using Matlab 2020a.

Link for the example: https://www.mathworks.com/help/physmod/sm/ug/sfull-vehicle-on-four-post-testrig.html

When I try to change the tyre radius, wheelbase, spring constants, damping coeffients, etc, the model compiles without any problems.

However when I try to change the coordinates of any of the points of the suspension geometry (even by less than 1 mm), the model can not compile and a huge list of errors appear on the Diagnostic Viewer.

I already de-linked all the blocks from the example and removed the example folder from the path so it does not call any functions or loads any variable from that folder.

I hope you can help me,

Thank you

Ricardo

Answer 1

[Steve Miller]

Hi Ricardo,

There is a setting you should clear if you alter the hardpoint locations. Clear this checkbox so that it doesn't use the operating point that has been configured for the default set of hardopints.

We put this in so that the car would start all settled on the 4-post testrig. The operating point defines the initial position (and velocity) of all degrees of freedom. If you change a hardpoint, those settings are no longer value. Clear the checkbox and you can modify the hardpoints.

I would take a look at the Simscape Vehicle Templates. It is a set of examples you can download for free and use with MATLAB, Simulink, and Simscape.

https://www.mathworks.com/matlabcentral/fileexchange/79484-simscape-vehicle-templates

We have added a few more suspension templates, including ones that are much closer to Formula Student vehicles. Below is a screenshot of how to select a vehicle configured with the Formula Student suspension (please forgive the non-standard steering wheel).

--Steve