The mixed real/virtual operator interface for ATHLETE (MSim-ATHLETE) is a new software system for operating manipulation and inspection tasks in JPL’s ATHLETE (All-Terrain Hex-Legged Extra-Terrestrial Explorer). The system presents the operator with a graphical model of the robot and a palette of available joint types. Once virtual articulations are constructed for a task, the operator can move any joint or link, and the system interactively responds in real-time with a compatible motion for all joints that best satisfies all constraints.
Unique features of the software include:
- On-line topological dynamism: The key feature of MSim-ATHLETE is that it permits the kinematic structure of the operated mechanism to be changed dynamically by the operator. These changes are not (usually) meant to indicate actual changes in the physical system, but rather add/remove virtual extensions for constraining and parameterizing motions.
- Mixed reification: MSim-ATHLETE models two kinds of articulations: real articulations model the robot and virtual articulations model the virtual extensions.
- Pure kinematicity: MSim-ATHLETE is purely kinematic and thus does not require specifying any physics parameters, such as mass and friction properties.
- Useful handling of under- and over-constraint: MSim-ATHLETE allows the operator to specify both underand over-constrained motions. In both cases, several features help organize and structure the result, including prioritized constraints, explicit hierarchical decomposition, and least-squares solving.
This work was done by Jeffrey S. Norris and David S. Mittman of Caltech and Marsette A. Vona and Daniela Rus of Massachusetts Institute of Technology for NASA’s Jet Propulsion Laboratory. For more information, see http://www.mit.edu/~vona/MSim-ATHLETE/MSim-ATHLETE-info.html.