Through the use of functional magnetic resonance imaging (fMRI) in conjunction with a haptic device, it is possible to study changes in brain activity while a patient undergoes rehabilitation-like protocols. By measuring changes in brain activity of a patient undergoing neurorehabilitation during fMRI, optimal patient-specific therapy regimens might be obtained. This research aims to develop, characterize, and control a parallel three degrees of freedom magnetic resonance (MR) compatible haptic device, called the MR-SoftWrist, which can measure and support wrist movements during fMRI. Through a series elastic actuation (SEA) architecture, the device achieves accurate force control and can implement rehabilitation-like protocols. An MR-compatible design is achieved by using Delrin and brass for structural materials, non-magnetic ultrasonic motors for actuation, and custom phosphor bronze extension springs as the series elastic elements. Current projects include complete characterization of the MR-SoftWrist, implementation of impedance controllers on the device, advanced MR-compatibility analyses, and validation with human subjects.
A. Erwin, M. K. O’Malley, D. Ress, and F. Sergi. “Kinesthetic feedback during 2DOF wrist movements via a novel MR-compatible robot.” IEEE Transactions on Neural Systems and Rehabilitation Engineering (12/1 In Press, doi: 10.1109/TNSRE.2016.2634585).
A. Erwin, M. K. O’Malley, D. Ress, and F. Sergi. “Development, control, and MRI-compatibility of the MR-SoftWrist.” IEEE International Conference on Rehabilitation Robotics (ICORR), pp. 187-192, 2015. Best Student Paper Award.
F. Sergi, A. Erwin, and M. K. O’Malley. “Interaction control capabilities of an MR-compatible compliant actuator for wrist sensorimotor protocols during fMRI.” IEEE/ASME Transactions on Mechatronics, vol. 20, no. 6, pp. 2678-2690, 2015.