This work presents the design of a passivity-based controller and observer
for a robot manipulator interacting with a compliant environment Regulation
. of the contact force along the constrained direction and tracking of the
end-effector position along the unconstrained directions is achieved; semig
lobal exponential stability is proved. The central scheme is implemented in
the joint space, and experimental results are illustrated for an open cont
rol architecture industrial robot which is endowed with joint position sens
ors and wrist force sensor, but no joint velocity sensors.