  Mobile manipulators have been employed in many applications that are
traditionally performed by either multiple fixed-base robots or a large robotic
system. This capability is enabled by the mobility of the mobile base. However,
the mobile base also brings redundancy to the system, which makes mobile
manipulator motion planning more challenging. In this paper, we tackle the
mobile manipulator motion planning problem under the end-effector trajectory
continuity constraint in which the end-effector is required to traverse a
continuous task-space trajectory (time-parametrized path), such as in mobile
printing or spraying applications. Our method decouples the problem into: (1)
planning an optimal base trajectory subject to geometric task constraints,
end-effector trajectory continuity constraint, collision avoidance, and base
velocity constraint; which ensures that (2) a manipulator trajectory is
computed subsequently based on the obtained base trajectory. To validate our
method, we propose a discrete optimal base trajectory planning algorithm to
solve several mobile printing tasks in hardware experiment and simulations.
