3D position measurement based on force sensors for a one-wire haptic interface

The sensorial system of an haptic interface based on a single actuated wire is presented and discussed. Main characteristics of this device are that: a) it consists of a single wire properly connected to a finger of the operator, and controlled in such a way to allow interaction with virtual surfaces; b) the position of the end-point is computed on the basis of force measurement. In fact, in this haptic interface the measurement of the position in the 3-dimensional space 59 intrinsically connected to the force applied to the wire. In this paper, these points are addressed, illustrating the procedure for the determination of the interface end point position in 3D space, starting from force measurement. Moreover problems with sensor measures due to friction and noise, and their correlation with position computation are discussed. Finally, laboratory experiments are presented.