  The Modboat is an autonomous surface robot that turns the oscillation of a
single motor into a controlled paddling motion through passive flippers.
Inertial control methods developed in prior work can successfully drive the
Modboat along trajectories and enable docking to neighboring modules, but have
a non-constant cycle time and cannot react to dynamic environments. In this
work we present a thrust direction control method for the Modboat that
significantly improves the time-response of the system and increases the
accuracy with which it can be controlled. We experimentally demonstrate that
this method can be used to perform more compact maneuvers than prior methods or
comparable robots can. We also present an extension to the controller that
solves the reaction wheel problem of unbounded actuator velocity, and show that
it further improves performance.
