Criteri di gestione della ridondanza e controllo in forza per un'interfaccia aptica ridondante

This thesis talk about a redundant haptic interface with 3 degree of freedom and it propose an approach to solve the inverse kinematic and it's proposed a force control algorithm to control the interaction between haptic interface and virtual environments. The vertical translation is the redundant degree of freedom. This device is composed of two main mechanism: an upper parallel structure and one bottom rod-crank mechanism; the last one is used to increase the vertical translation of the end-effector. The first objective of this work is to propose some different approaches to solve the inverse kinematic of a redundant device; in this case are used some methodologies based on position space, velocity space and acceleration space. All those approaches are based on the null space of Jacobian matrix. The best method to menage the internal motions of device defines the configurations of the mechanisms in according of the frequency of end-effector’s acceleration. The control system is composed by an impedance control, an internal motion control and a noise observer. The impedence control generates a reference force in according of the desired virtual environment to simulate. The internal motion control generates an acceleration to project on null space of jacobian matrix. A null space velocity controller has been proposed using the pseudoinverse proposed weighed by the mass matrix. The noise observer generates a force in according of the frictions dissipations.