Widening 6-DOF haptic devices workspace with an additional degree of freedom

The aim of haptic interfaces is to enhance the user´s immersion in a virtual environment through the stimulation of the haptic sense. In the context of scale one applications in immersive environments, the haptic interface must provide a very large workspace without degrading transparency. To reach this goal, we investigated the addition of a 7th axis with larger range to a 6-DOF haptic device. This way, the workspace is increased while with a proper control scheme the dynamic properties of the initial device are saved. To ensure good control on this redundant system we use the notion of generalised dynamically consistent inverse of the Jacobian within a position-position control approach