  We present a reusable formally verified safety net that provides end-to-end
safety and liveness guarantees for 2D waypoint-following of Dubins-type ground
robots with tolerances and acceleration. We: i) Model a robot in differential
dynamic logic (dL), and specify assumptions on the controller and robot
kinematics, ii) Prove formal safety and liveness properties for
waypoint-following with speed limits, iii) Synthesize a monitor, which is
automatically proven to enforce model compliance at runtime, and iv) Our use of
the VeriPhy toolchain makes these guarantees carry over down to the level of
machine code with untrusted controllers, environments, and plans. The
guarantees for the safety net apply to any robot as long as the waypoints are
chosen safely and the physical assumptions in its model hold. Experiments show
these assumptions hold in practice, with an inherent trade-off between
compliance and performance.
