  This paper proposes an initial theory for robotic systems that can be fully
self-maintaining. The new design principles focus on functional survival of the
robots over long periods of time without human maintenance. Self-maintaining
semi-autonomous mobile robots are in great demand in nuclear disposal sites
from where their removal for maintenance is undesirable due to their
radioactive contamination. Similar are requirements for robots in various
defence tasks or space missions. For optimal design, modular solutions are
balanced against capabilities to replace smaller components in a robot by
itself or by help from another robot. Modules are proposed for the basic
platform, which enable self-maintenance within a team of robots helping each
other. The primary method of self-maintenance is replacement of malfunctioning
modules or components by the robots themselves. Replacement necessitates a
robot team's ability to diagnose and replace malfunctioning modules as needed.
Due to their design, these robots still remain manually re-configurable if
opportunity arises for human intervention. Apart from the basic principles, an
evolutionary design approach is presented and a first mathematical theory of
the reliability of a team of self-maintaining robots is introduced.
