This paper deals with the implementation of a hybrid\ud force/velocity controller for the automatic edge following of\ud two-dimensional unknown planar contours performed by an industrial robot manipulator. In particular, the authors address\ud the problem of compensating the joint friction effects that have to be taken into account in the controller design in order to achieve a reasonable performance with regards to normal force and tangential velocity errors. For that reason, two model-based friction-compensation methods are compared: a static method, based on a previously identified model, and an adaptive method, where joint friction parameters are recursively updated. By means of an extensive experimental activity, it is shown that, in spite of its simplicity and despite the friction effects changing in time during the robot operations, the devised adaptive procedure obtains a\ud high performance in different operating conditions

No abstract

No abstract

No abstract

a t t a 0 i t i a . c n r . i t AbstractThis paper deals with the experimental charactheritation of an hybrid force/velocity controller for contour tracking tasks of objects with unknown shape.perfoned by industrial robot manipulators. In particular, ' we address the problem of the presence of elasticities in joint transmissions, and we show that this can cause the occurrence of large force oscillations depending on the robot configuration. We ako show that to compensate for them it is necessary to employ an additional normal velocity feedback loop. Ezperimental results have been obtained with a two degrees-of-freedom SCARA robot.