Lego mindstorms NXT 3D designer and simulator

This research implemented a robot designer and robot simulator with an RXE interpreter for constructing and testing Lego Mindstorms NXT robot in a virtual environment. The research also produced a parts library collecting the graphical and collision meshes of Lego Mindstorms NXT parts, and developed the Lelogo file format specification for the accompanying part connectivity descriptors. Development of the robot designer encountered connectivity issues with a physics-based design system, and eventually evolved to a simpler non-physics-based designer with automatic part connectivity detection. There were also issues with the physics library regarding assignment of rotational velocity to joints, joint constraints unable to hold the bodies within specified degrees of freedom, and referencing between bodies and joints all of these were remedied. Testing of the robot simulator revealed that the implementation was dependent on system performance, which resulted in non-repeatability of tests. Acceleration scaling was tested and was demonstrated that it can reduce interpretation and unstable movement of physics bodies. This research is a proof of concept that indirectly encoded models can be used in simulator application to take advantage of additional connectivity information