  Long-term autonomy in service robotics is a current research topic,
especially for dynamic, large-scale environments that change over time. We
present Sobi, a mobile service robot developed as an interactive guide for open
environments, such as public places with indoor and outdoor areas. The robot
will serve as a platform for environmental modeling and human-robot
interaction. Its main hardware and software components, which we freely license
as a documented open source project, are presented. Another key focus is Sobi's
monitoring system for long-term autonomy, which restores system components in a
targeted manner in order to extend the total system lifetime without unplanned
intervention. We demonstrate first results of the long-term autonomous
capabilities in a 16-day indoor deployment, in which the robot patrols a total
of 66.6 km with an average of 5.5 hours of travel time per weekday, charging
autonomously in between. In a user study with 12 participants, we evaluate the
appearance and usability of the user interface, which allows users to
interactively query information about the environment and directions.
