Preliminary two dimensional haptic thresholds and task performance enhancements

Many tasks may be performed with greater efficiency and speed with haptic assistance. Using the Penbased Haptic Display, a low-power, low-friction, and high-precision device, we performed two separate experiments to measure two properties of human/haptic interactions. In the first experiment, we measured the level of force at which a subject may detect the presence of haptic feedback at a 71% accuracy level using a converging adaptive threshold algorithm. The average haptic threshold of eleven subjects was 20.8 milliNewtons. The second experiment quantifies changes in task performance using Fitts´ Law. We measured improvements at three force levels compared to no force.