Effects of vibrotactile feedback on human control performance in a dynamical stabilization task

While research has demonstrated how vibrotactile devices can be effectively used to guide human behavior, efficient mappings of vibration patterns for spatial guidance in time-critical dynamical tasks have not yet been understood. In this paper, we contrast two types of action-dependent, haptic stimulus designs to demonstrate the different effects of vibrotactile feedback on the human control performance. A wireless bracelet is used to provide patterns of vibrotactile stimuli in real-time, representing either optimal hand velocity or acceleration for the stabilization of an inverted pendulum. The optimal control behavior is supplied by a linear quadratic regulator. The analyses of the participants´ stabilization and learning behavior revealed a significant improvement caused by the additional velocity-dependent feedback. The results are consistent with previous research, which indicates that the human sensory-motor system is generally more sensitive to velocity than acceleration information. In summary, the present paper suggests how human-centric vibrotactile stimuli should be designed and how they can be effectively transmitted to the human user for time-critical behavioral guidance.