  RoboChart is a core notation in the RoboStar framework which brings modern
modelling and formal verification technologies into software engineering for
robotics. It is a timed and probabilistic domain-specific language for robotics
and provides a UML-like architectural and state machine modelling. This work
presents RoboCertProb for specifying quantitative properties of probabilistic
robotic systems modelled in RoboChart. RoboCertProb's semantics is based on
PCTL*. To interpret RoboCertProb over RoboChart models, we give a Markov
semantics (DTMCs and MDPs) to RoboChart, derived from its existing
transformation semantics to the PRISM language. In addition to property
specification, RoboCertProb also entitles us to configure loose constants and
unspecified functions and operations in RoboChart models. It allows us to set
up environmental inputs to verify reactive probabilistic systems not directly
supported in probabilistic model checkers like PRISM because they employ a
closed-world assumption. We implement RoboCertProb in an accompanying tool of
RoboChart, RoboTool, for specifying properties and automatically generating
PRISM properties from them to formally verify RoboChart models using PRISM. We
have used it to analyse the behaviour of software controllers for two real
robots: an industrial painting robot and an agricultural robot for treating
plants with UV lights.
