Haptics – #sirslab paper published on IEEE Robotics and Automation Letters (RA-L)

The hBracelet: a wearable haptic device for the distributed mechanotactile stimulation of the upper limb

Leonardo Meli, Irfan Hussain, Mirko Aurilio, Monica Malvezzi, Marcia K. O’MalleDomenico Prattichizzo.

DOI: 10.1109/LRA.2018.2810958

Abstract.  Haptic interfaces are mechatronic devices designed to render tactile sensations; although they are typically based on robotic manipulators external to the human body, recently, interesting wearable solutions have been presented. Towards a more realistic feeling of virtual and remote environment interactions, we propose a novel wearable skin stretch device for the upper limb called “hBracelet”. It consists of two main parts coupled with a linear actuator. Each part contains two servo actuators that move a belt. The device is capable of providing distributed mechanotactile stimulation on the arm by controlling the tension and the distance of the two belts in contact with the skin. When the motors spin in opposite directions, the belt presses into the user’s arm, while when they spin in the same direction, the belt applies a shear force to the skin. Moreover, the linear actuator exerts longitudinal cues on the arm by moving the two parts of the device. In this work we illustrate the mechanical structure, working principle, and control strategies of the proposed wearable haptic display. Furthermore, we present a qualitative experiment in a teleoperation scenario as a case study to demonstrate the effectiveness of the proposed haptic interface and to show how a human can take advantage of multiple haptic stimuli provided at the same time and on the same body area. The results show that the device is capable of successfully providing information about forces acting at the remote site, thus improving the overall telepresence.


A video showing the main concept of the work can be watched at

The pdf of the paper can be downloaded at http://sirslab.dii.unisi.it/papers/2018/Meli18_hBracelet.pdf

The paper can be cited using the following bibtex item

author={L. Meli and I. Hussain and M. Aurilio and M. Malvezzi and M. K. O’Malley and D. Prattichizzo},
journal={IEEE Robotics and Automation Letters},
title={The hBracelet: A Wearable Haptic Device for the Distributed Mechanotactile Stimulation of the Upper Limb},
keywords={Actuators;Belts;Force;Haptic interfaces;Pulleys;Robots;Skin;Haptics and haptic interfaces;human-centered robotics;telerobotics and teleoperation;wearable robots},


This work will be presented at the IEEE International Conference on Robotics and Automation (ICRA 2018) that is held 21-25 May in Brisbane, Australia.

New paper published on IEEE Transactions on Haptics: “Digital Handwriting with a Finger or a Stylus: a Biomechanical Comparison”

The human hand is highly versatile and easily adaptable to a variety of manipulation tasks, exposing flexible solutions to the needs of control. In daily life, humans beings are, apparently without effort, able to generate complex and elegant movements of the hand and fingers, such as typing on keyboards, playing a musical instrument, or writing. 

In this paper we focus on the analysis of human hand movements during handwriting tasks, a subject which has been studied for many decades.

Screen shot 2015-12-15 at 1.04.49 PM

We present for the first time, at the best of our knowledge, a methodological approach based on the biomechanics of the human hand to compare two different input methods, i.e., the finger and the stylus, in digital handwriting tasks.

Performance of two input methods is evaluated and compared in terms of manipulability indexes in the task space, i.e., the ratio between a measure of performance (displacement, velocity, force in the task space) and a measure of effort in the input/joint space.

Screen shot 2015-12-15 at 1.14.02 PMBeside the mathematical analysis based on a biomechanical model of the hand, two experiments are presented, in which subjects were asked to write on a touchscreen using either their index finger, or a stylus.

The results (both analytical and experimental) assess that writing with the finger is more suitable for performing large, but not very accurate motions, while writing with the stylus leads to a higher precision and more isotropic motion performance.

PDF: http://sirslab.dii.unisi.it/papers/2015/Prattichizzo.TOH.2015.Handwriting.pdf

D. Prattichizzo, L. Meli, and M. Malvezzi.
“Digital Handwriting with a Finger or a Stylus: a Biomechanical Comparison.”
IEEE Transactions on Haptics, 2015.
DOI: 10.1109/TOH.2015.2434812