Signal Detection Performance with a Haptic Device

Abstract

Haptic interfaces are becoming more widely used in virtual reality simulations because of their enhancement to performance in training and simulation. Unintended vibration degrades the effectiveness of a haptic device and can reduce the user's ability to detect small details in the surface of simulated hard objects. Two important design factors for controlling haptic device vibrations are servo update rate and resistive force magnitude. This work employs a signal detection and receiver operator characteristic methodology to evaluate the interaction of these two factors on a user's ability to perceive small details in a hard surface. In a two-factor, full factorial experiment, six male research participants rated their confidence in detecting a 5mm upward step along a simulated hard surface. The independent variables were resistive force magnitude (1.63N or 4.88N) and update rate (468Hz or 1630Hz). The results indicate a significant interaction of the two variables. Participants demonstrated a 69% success rate with the strong force, slow update rate compared with a 86% success rate in the other 3 conditions. The participants may have employed a strategy of detecting the lack of oscillations when entering the surface and then noted their kinesthetic motion while moving back to the oscillating state experience when sliding along the surface of the simulated edge. Either increasing the update rate or reducing the resistive force magnitude can mitigate the effects of vibration when using a haptic device.