  This paper presents a novel Luenberger-style observer for robot manipulators
with position measurements. Under the assumption that the state evolutions that
are to be observed have bounded velocities, it is shown that the origin of the
observation error dynamics is globally exponentially stable and that the
corresponding convergence rate can be made arbitrarily high by increasing a
gain of the observer. Comparisons and relations between the proposed observer
and existing observers are discussed. The effectiveness of the result here
presented is illustrated by a simulation of the observer for the Pendubot, an
underactuated two-joint manipulator.
