A haptic input device comprises a hexapod or pentapod parallel linkage
mechanism with force feedback effected by proportional control of
magneto-restrictive fluid brakes constraining the measurement of the
struts of the mechanism, through their base nodes. In the pentapod
version of the haptic data input device, a haptic stylus is employed
which includes an annular compliant feature that can be squeezed and
whose squeeze pressure can be monitored.