Departmental Papers (ESE)


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.

Document Type

Conference Paper

Subject Area


Date of this Version



Copyright YEAR 2009. Reprinted from:
Winfree, K.N.; Gewirtz, J.; Mather, T.; Fiene, J.; Kuchenbecker, K.J., "A high fidelity ungrounded torque feedback device: The iTorqU 2.0," EuroHaptics conference, 2009 and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems. World Haptics 2009. Third Joint , vol., no., pp.261-266, 18-20 March 2009

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to By choosing to view this document, you agree to all provisions of the copyright laws protecting it.


feedback, haptic interfaces, torque, angular momentum, angular velocity, haptic applications, iTorqU 2.0, ungrounded torque feedback device



Date Posted: 29 June 2009