@conference {BBLP93, title = {A variable structure approach to force/motion control of robot manipulators}, booktitle = {Proc. Int. Conf. FAST - BIAS}, year = {1993}, address = {Milan, Italy, November 23-25 1993}, keywords = {Robotics}, author = {A. Balestrino and A. Bicchi and A. Landi and D Prattichizzo} }