  As robot systems become more ubiquitous, developing understandable robot
systems becomes increasingly important in order to build trust. In this paper,
we present an approach to developing a holistic robot explanation system, which
consists of three interconnected components: state summarization, storage and
querying, and human interface. To find trends towards and gaps in the
development of such an integrated system, a literature review was performed and
categorized around those three components, with a focus on robotics
applications. After the review of each component, we discuss our proposed
approach for robot explanation. Finally, we summarize the system as a whole and
review its functionality.
