VIBRATION DAMPING AND 2ND-ORDER SLIDING MODES IN THE CONTROL OF A SINGLE FINGER OF THE AMADEUS GRIPPER

The vibration clamping problem relevant to a single element (finger) o f the AMADEUS gripper is addressed. A simplified model of such an elem ent, constituted by three bellows connected to two plates, one fixed a nd the other (the tip) free, has been derived The elastic constants in this model are assumed uncertain. Therefore, a sliding mode approach has been adopted to damp the oscillations and perform the dynamic deco upling between displacements and rotations. Then, the transmission del ays have been taken into account and an unconventional adaptive slidin g mode strategy has been designed. In order to avoid the chattering ph enomenon and eliminate the drawbacks typical of hydraulic valves (low bandwidth and hysteresis), a new actuation system, driven by a new sli ding mode control algorithm, has been developed and experimentally tes ted.