Open Modelica

https://www.openmodelica.org/

Open source mechatronics software.

You Can Model in OpenModelica and Render in a Game Engine

Simulations of real machines controlled by a user interface can be simulated. Great way to prototype machines.

See paper - controlling a virtual excavator with an Arduino physical interface.

http://www.ep.liu.se/ecp/132/096/ecp17132879.pdf