Method and apparatus for compensating for position slip in interface devices

A device comprising:

• a manipulandum movable in at least one degree of freedom;
• a position sensor operative to detect a position of said manipulandum in at least one of said degrees of freedom;
• a mechanical transmission coupled between said manipulandum and said position sensor;
• and
• a reference sensor operative to detect the motion of at least one reference location of said manipulandum.

A method comprising:

• enabling a determination of a device position delta from a sensed position of a manipulandum of an interface device in a degree of freedom, said position delta indicating a change in an actual position of said manipulandum;
• enabling a determination of whether a position slip has occurred in said position sensing system, said position slip caused by a change in position of said manipulandum that was not sensed by a sensor of said interface device;
• and
• enabling a correction of an error in said sensed position caused by said position slip by adjusting said sensed position to take into account said position slip, and enabling said adjusted position be provided as said actual position of said manipulandum.