Patent ID: 7880717

Claim:
A haptic interface device to provide haptic interaction to a user manipulating a tool, the haptic interface device comprising: an attachment point; a plurality of cables coupled to the attachment point, the plurality of cables comprising a first, a second, a third, and a fourth length of cable extending from the attachment point; a first tool translation effecter device having a first cable guide, a second tool translation effecter device having a second cable guide, a third tool translation effecter device having a third cable guide, and a fourth tool translation effecter device having a fourth cable guide, the first, the second, the third and the fourth cable guides positioned, relative to each other, such that each of the first, the second, the third, and the fourth cable guides occupies a vertex of a tetrahedron, each tool translation effecter device having coupled thereto, a respective one of the first, the second, the third, and the fourth lengths of cable such that, as the attachment point moves, each of the first, the second, the third, and the fourth lengths of cables is retracted or paid out accordingly by the respective tool translation effecter device, each tool translation effecter device including controlling means for selectively varying an active tension on the respective length of cable; metering means for metering each of the first, the second, the third, and the fourth length of cables as they are retracted and paid out; and establishing means for establishing a respective distance between each of the first, the second, the third, and the fourth cable guides and the attachment point, the establishing means including a memory configured to receive and store, prior to a complete shutdown of the haptic interface device, the respective distances between each of the first, the second, the third, and the fourth tool translation effecter devices and the attachment point, and to provide the stored distances during a startup procedure.