A Basic Robotic Excavator (the Glenn Digger): Description, Design, and Initial Operation

This paper describes design, commercial part selections, fabrication, assembly, installation, and initial operation of a two degree of freedom robotic excavator. Colloquially referred to as the NASA Glenn Digger, it was designed specifically to be mounted onto, and to operate with, then newly developed Centaur 2 robotic mobility base. The excavator, when mounted to Centaur 2, is designed to scoop loose regolith from terrain, raise its loaded bucket up and dump load into a hopper of at least a 1-m-height. The hopper represents input to a machine that would process raw material, such as to produce oxygen from lunar regolith as would be required for long-term lunar habitation. This equipment debuted at annual Research and Technology Studies (Desert RATS, Ref. 1) event held north of Flagstaff, Arizona, in September of 2010, when Digger was successfully joined to Centaur 2 and shoveling articulation was demonstrated. During 2011, hardware was modified for added strength, strain gauges were added to measure loads, and controls were improved in preparation for 2011 Desert RATS event, where additional field operations experience was gained.