Fault tolerant action selection for planetary rover control

The ability of a small rover to operate semi-autonomously in a hazardous planetary environment was recently demonstrated by the Sojourner mission to Mars in July of 1997. Sojourner stayed within a 50 meter radius of the Pathfinder lander. Current NASA plans call for extended year-long multikilometer treks for the 2003 and 2005 missions. A greater deal of rover autonomy is required for such missions. We have recently developed a hybrid wavelet/neural network based system called BISMARC (Biologically Inspired System for Map-based Autonomous Rover Control), that is capable of such autonomy. Simulations reported at this meeting last year demonstrated that the system is capable of control for multiple rovers involved in a multiple cache recovery scenario. This robust behavior was obtained through the use of a free-flow hierarchy (FFH) as an action selection mechanism. This paper extends BISMARC to include fault tolerance in the sensing and mechanic rover subsystems. The results of simulation studies in a Mars environment are also reported.