Control of a high fidelity ungrounded torque feedback device: The iTorqU 2.1

This paper outlines how a control moment gyroscope can be used to generate haptic torque feedback while minimizing the effects of a constrained gimbal workspace. We present the design of the iTorqU 2.1 and discuss how it compares to previously developed systems. We then detail the control algorithms we have developed for both transparency and torque output modes. The prescribed transparency controller is typical in design, but the torque output algorithm is novel to this type of haptic device. It makes use of a series of position-p-at-time-t commands, which we call packets. Five packet designs were considered in this research, but we have included only the most important three in this paper. While this research deals with torque feedback, it ultimately presents a method for working with devices that are limited by the need for continuous reset to a home position before subsequent outputs.