A simple controller is presented for the regulation problem of robot a
rms with flexible links under gravity. It consists of a joint PD feedb
ack plus a constant feedforward. Global asymptotic stability of the re
ference equilibrium state is shown under a structural assumption about
link elasticity and a mild condition on the proportional gain. The re
sult holds also in the absence of internal damping of the flexible arm
. A numerical case study is presented.