sympy - mechanics & pydy - constraints question

[Jan]

I am in the process of teaching myself how to use the sympy mechanics package for multi-body modelling with the addition of the pydy package.

I am running into an issue when using the generate_ode_function tool in pydy and am looking for a bit of guidance as to what is going on.

An example of the issue that I am running into is here - I have adapted the quick-return example from this article to include an additional body, attached to upper sliding point. I am able to run the article's model without issue and can match the results seen there, however when I try to attach this additional body, the simulation falls apart with the constraints failing.

The additional body is the top grey part, pointing upward in the below picture.

 I imagine the issue that I am running into is due to the way that the constraints are defined, however I can't see how the constraints on the new body are different from what was required for the article's model.