  We present a robot base placement and control method that enables a mobile
manipulator to gracefully recover from manipulation failures while performing
tasks on-the-move. A mobile manipulator in motion has a limited window to
complete a task, unlike when stationary where it can make repeated attempts
until successful. Existing approaches to manipulation on-the-move are typically
based on open-loop execution of planned trajectories which does not allow the
base controller to react to manipulation failures, slowing down or stopping as
required. To overcome this limitation, we present a reactive base control
method that repeatedly evaluates the best base placement given the robot's
current state, the immediate manipulation task, as well as the next part of a
multi-step task. The result is a system that retains the reliability of
traditional mobile manipulation approaches where the base comes to a stop, but
leverages the performance gains available by performing manipulation
on-the-move. The controller keeps the base in range of the target for as long
as required to recover from manipulation failures while making as much progress
as possible toward the next objective.
  See https://benburgesslimerick.github.io/MotM-FailureRecovery for videos of
experiments.
