Lessons in using vibrotactile feedback to guide fast arm motions

We present and evaluate an arm-motion guidance system that uses magnetic tracking sensors and low cost vibrotactile actuators. The system measures the movement of the user's arm and provides vibration feedback at the wrist and elbow when they stray from the desired motion. An initial study was conducted to investigate whether adding tactile feedback to visual feedback reduces motion errors when a user is learning a new arm trajectory. Although subjects preferred it, we found that the addition of tactile feedback did not affect motion tracking performance. We also found no strong preference or performance differences between attractive and repulsive tactile feedback. Some factors that may have influenced these results include the speed and the complexity of the tested motions, the type of tactile actuators and drive signals used, and inconsistencies in joint angle estimation due to Euler angle gimbal lock. We discuss insights from this analysis and provide suggestions for future systems and studies in tactile motion guidance.