Trep is a software suite for discrete mechanics developed by Todd Murphey's research group (mainly through Elliot Johnson's PhD research).  Trep is a Python module for modeling articulated rigid body mechanical systems in generalized coordinates. Trep supports basic simulation but it is primarily designed to serve as a calculation engine for analysis and optimal control algorithms that require 1st and 2nd derivatives of the system's dynamics. 

More information, and downloads can be found here.

The Digital Rat is software from the Hartmann group that aims to enable morphologically and mechanically accurate modeling of the rat head and vibrissal (whisker) array. Our long-term goal is to develop a simulation environment that can be used to model the spatiotemporal patterns of mechanical input to vibrissae during the rat's tactile exploratory behaviors.

Visit this page for software downloads and user guides.