Dr. Heba Khamis Seminar


Encoding of Friction by Tactile Afferents


Adjustments to frictional forces are crucial to maintain a safe grip during precision object handling in both humans and robotic manipulators. In humans, nerve afferents associated with approximately 17000 tactile mechanoreceptors signal tactile information to the brain. It is a widely held belief that the friction between the finger pad and an object is signalled at initial contact and this information is updated during object manipulation. A theory exists to explain the biomechanics of this initial contact under varying frictions however this theory has never been proven, and attempts at demonstrating afferent responses to varying frictions at initial contact have been inconclusive. Furthermore it has never been shown how afferents may encode the transition from grip to slip under varying frictions. 

Two recent works are presented here showing that a small number of afferent responses could (i) disentangle the normal force application ramp rate, texture of the object and the friction between the finger pad and the object, at initial contact, and (ii)  provide information about the current tangential/normal force ratio normalised by the coefficient of friction, during the grip-to-slip transition.

This work is important for understanding human dexterous manipulation and inspiring improvements in robotic grippers and prostheses.


Dr Heba Khamis completed her Bachelor of (Software) Engineering/Bachelor of Medical Science at the University of Sydney (USyd), in 2007, and also completed her PhD at USyd in developing methods for epileptic seizure detection from EEG. She is now an Associate Lecturer at the Graduate School of Biomedical Engineering at The University of New South Wales (UNSW).

Her primary research interests revolve around the application of signal processing and pattern recognition techniques to solve or understand biomedical engineering problems, particularly for decoding the neural responses of populations of afferent mechanoreceptors in the fingertip, which will improve our understanding of why the human sense of touch is so sophisticated. This work is also using these discoveries to design tactile sensors, which might provide upper limb prosthetics of the future, or autonomous robotic manipulators, with a sense of touch.

Friday, August 29, 2014 - 2:00pm to 3:00pm
Civil Conference Room, A230
2145 Sheridan Rd.
Evanston , IL
United States