Interactive robot joint design, analysis and prototyping

NASA's Johnson Space Center has developed a general geometric model of a manipulator joint that allows for the interactive design and analysis of robot prototypes. The interactive design software analyzes joint geometries for various performance issues, and has been connected to a Stereolithography Apparatus (SLA) for the rapid production of full scale mechanism models. The software, called Module Maker, uses variational geometry to connect the joint model's 36 independent, geometric variables with over 100 dependent values that define the solids of a general 2 degree of freedom joint. A user can interactively "stretch" and edit the joint's structure, with a 3D rendering that updates in real time, while displaying numeric values for review. Analysis routines developed to support the interactive design process include a general evaluation of the joint's new range of motion, weight, moments of inertia, centroids, heat transfer coefficients and a calculation of the joint's Denavit-Hartenberg (DH) parameters. The final step in the design cycle is to prototype the module elements using an SLA that make full scale, polyurethane components.