Discrimination thresholds for communicating rotational inertia and torque using differential skin stretch feedback in virtual environments

This paper presents a device for providing tactile feedback through four sliding contactor plates placed in the device's handle and grasped in the palm of the hand. This device is capable of communicating virtual forces and torques to a user through the motion of the independently controlled slider plates. Integrated device motion tracking allows simulation software to command our haptic device to mimic the in-hand friction and shear forces experienced by a user during sports activities such as swinging a tennis racket or catching a lacrosse ball. These situations present the user with the resistance of rotational inertia and impact torques. We present two experiments that provide an initial characterization of the range of rotational inertia and impact torques that can be presented with the current prototype. Weber fractions for discriminating rotational inertia and torque in the two experiments ranged from 15-25%. Such feedback can be used to give the sense of mass to a virtual object.