Tactile Perception of Rotational Sliding

We present a new tactile display for rendering rotational friction at the fingertips. To inform the design and control of this device, we have conducted an initial set of perceptual experiments to investigate perceptual thresholds for rates of rotational slipping at the fingertips. It was found that humans can discriminate a change in rotational sliding rate of 4.13-28.04 rad/sec from a reference rate of 1.57-25.13 rad/sec. An initial device design and prototype are presented. The device utilizes a small friction disk housed in a thimble, driven remotely from a motor worn on the user´s wrist. The device directly integrates with a robotic force feedback arm, preserving the force feedback functionality while adding the tactile information on frictional sliding. Insights from the presented psychophysical experiments and initial device prototype will be utilized in the design of the next generation of rotation friction devices that will be used in multi-finger grasp studies