A high fidelity ungrounded torque feedback device: The iTorqU 2.0

This paper discusses the design and operation of the iTorqU 2.0, an ungrounded, handheld torque feedback device for haptic applications. Based upon the gyroscopic effect, the iTorqU 2.0 uses a metal flywheel inside of a two-axis actuated gimbal to create directional torques that are applied to the user's hand. The coupling of angular velocity and angular momentum creates a torque that is orthogonal to the two input angular velocities, giving the user the impression that their hand is being twisted in free air. Following a review of prior work in the field of ungrounded torque feedback devices, we first present our preliminary prototype, the iTorqU 1.0. Building on empirical observations and user feedback from a public demonstration, we revised and augmented this design to create the iTorqU 2.0. This paper covers the major mechanical, electrical, and controls design considerations that went into creating the iTorqU 2.0, along with an analysis of its torque output capabilities.