The influence of changing haptic refresh-rate on subjective user experiences-lessons for effective touch-based applications

When producing haptic renderings, it is important to know the minimum subjectively acceptable refresh rate to avoid simulation of overly complex materials. In doing so, factors such as speed/force of hand movements or material stiffness must be taken into account. An experiment was conducted to identify minimum acceptable haptic refresh rate as a function of the latter factor. A threshold of around 500Hz was found although, surprisingly, no effect of material stiffness occurred. This may have resulted from variations in participants’ response strategies. A second experiment used a modified procedure to avoid this problem. However, the predicted effect was still not found. The study highlights the importance of cognitive factors in users' interpretations of sensations derived from touch and the need to account for them when designing experiments.