New paper accepted for publication in the Proceedings of the 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2015)

In this paper, we present a haptic guidance policy to steer the user along predefined paths and we evaluate a predictive approach to compensate actuation delays that humans have when they are guided along a given trajectory via sensory stimuli.

The proposed navigation policy exploits the nonholonomic nature of human locomotion in goal directed paths, which leads to a very simple guidance mechanism. The proposed method has been evaluated in a real scenario where seven human subjects were asked to walk along a set of predefined paths via vibrotactile cues. Their poses as well as the related distances from the path have been recorded using an accurate optical tracking system.

Results revealed that an average error of 0.24 m is achieved by using the proposed haptic policy, and that the predictive approach does not bring significant improvements to the path following problem for what concerns the distance error. On the contrary, the predictive approach achieved a definitely lower activation time of the haptic interfaces.

M. Aggravi, S. Scheggi, D. Prattichizzo. Evaluation of a predictive approach in steering the human locomotion via haptic feedback. In Proc. IEEE/RSJ International Conference Intelligent Robots and Systems. In Press, 2015.

New paper published on the IEEE Transactions on Biomedical Engineering: “Cutaneous Feedback of Fingertip Deformation and Vibration for Palpation in Robotic Surgery”

Despite its expected clinical benefits, current teleoperated surgical robots do not provide the surgeon with haptic feedback largely because grounded forces can destabilize the system’s closed-loop controller.

This article presents an alternative approach that enables the surgeon to feel fingertip contact deformations and vibrations while guaranteeing the teleoperator’s stability.

We implemented our cutaneous feedback solution on an Intuitive Surgical da Vinci Standard robot by mounting a SynTouch BioTac tactile sensor to the distal end of a surgical instrument and a custom cutaneous display to the corresponding master controller. As the user probes the remote environment, the contact deformations, DC pressure, and AC pressure (vibrations) sensed by the BioTac are directly mapped to input commands for the cutaneous device’s motors using a model-free algorithm based on look-up tables. The cutaneous display continually moves, tilts, and vibrates a flat plate at the operator’s fingertip to optimally reproduce the tactile sensations experienced by the BioTac.

We tested the proposed approach by having eighteen subjects use the augmented da Vinci robot to palpate a heart model with no haptic feedback, only deformation feedback, and deformation plus vibration feedback. Fingertip deformation feedback significantly improved palpation performance by reducing the task completion time, the pressure exerted on the heart model, and the subject’s absolute error in detecting the orientation of the embedded plastic stick. Vibration feedback significantly improved palpation performance only for the seven subjects who dragged the BioTac across the model, rather than pressing straight into it.

system

C. Pacchierotti, D. Prattichizzo, K. J. Kuchenbecker. Cutaneous feedback of fingertip deformation and vibration for palpation in robotic surgery. IEEE Transactions on Biomedical Engineering. In Press, 2015. pdf

Teleoperation of steerable flexible needles by combining kinesthetic and vibratory feedback

A new journal article has been accepted for publication in the IEEE Transactions on Haptics!

Reference:
C. Pacchierotti, M. Abayazid, S. Misra, D. Prattichizzo. “Teleoperation of steerable flexible needles by combining kinesthetic and vibratory feedback”. IEEE Transactions on Haptics, 2015.

PaAbMiPr-TOH15
Abstract:
Needle insertion in soft-tissue is a minimally invasive surgical procedure that demands high accuracy. In this respect, robotic systems with autonomous control algorithms have been exploited as the main tool to achieve high accuracy and reliability. However, for reasons of safety and responsibility, autonomous robotic control is often not desirable. Therefore, it is necessary to focus also on techniques enabling clinicians to directly control the motion of the surgical tools. In this work we address that challenge and present a novel teleoperated robotic system able to steer flexible needles.

The proposed system tracks the position of the needle using an ultrasound imaging system and computes needle’s ideal position and orientation to reach a given target. The master haptic interface then provides the clinician with mixed kinesthetic-vibratory navigation cues to guide the needle toward the computed ideal position and orientation.
Twenty participants carried out an experiment of teleoperated needle insertion into a soft-tissue phantom, considering four different experimental conditions. Participants were provided with either mixed kinesthetic-vibratory feedback or mixed kinestheticvisual feedback. Moreover, we considered two different ways of computing ideal position and orientation of the needle: with or without set-points. Vibratory feedback was found more effective than visual feedback in conveying navigation cues, with a mean targeting error of 0.72 mm when using set-points, and of 1.10 mm without set-points.

Full-text PDF:
http://sirslab.dii.unisi.it/papers/2015/Pacchierotti.TOH.2015.Haptics.Fin.pdf

VIDEO:

Wearable Haptics and Hand Tracking @ SIGGRAPH 2014

Our lab is heading to Vancouver to present the paper

Wearable Haptics and Hand Tracking via an RGB-D Camera
for Immersive Tactile Experiences
.

to the upcoming SIGGRAPH 2014 conference.

Screenshot from 2014-08-08 10:52:52
Enjoy the video!

One of our journal papers listed as the most popular TOH paper in IEEEXplore

The journal paper “Towards Wearability in Fingertip Haptics: A 3-DoF Wearable Device for Cutaneous Force Feedback” by D. Prattichizzo, F. Chinello, C. Pacchierotti, and M. Malvezzi is now listed in IEEEXplore as the most popular IEEE Transactions on Haptics paper, with over 400 downloads!

 

IEEE Xplore: Haptics, IEEE Transactions on - (Home) - Google Chrome_003IEEE Xplore Abstract (Metrics) - Towards Wearability in Fingertip Haptics: A 3-DoF Wearable Device for Cutaneous Force Feedback - Google Chrome_004

You can download the paper from here.

Mapping synergies from human to robotic hands with dissimilar kinematics: an object based approach

Robotic hands differ in kinematics, dynamics, programming, control and sensing frameworks. Their common character is redundancy, which undoubtedly represents a key feature for dexterity and flexibility, but it is also a drawback for integrated automation since it typically requires additional efforts to seamlessly integrate devices, particularly robotic hands, in industrial scenario. This research focuses on the mapping between hands with dissimilar kinematics. It is based on the argument that the reflected optimality of the pattern of grasping forces emerging from human hand synergies should be matched, in some sense, by the sought for postural synergies of robotic hands. As a natural consequence of the proposed approach, postural synergies for different kinematic structures could look entirely different in geometric shape. This difference should be a consequence of aspects such as different dimensions, kinematic structures, number of fingers, compliance, contact properties which cannot come into play if a gross geometric mapping is applied. The proposed mapping is based on the use of a virtual sphere and will be mediated by a model of an anthropomorphic robotic hand able to capture the idea of synergies in human hands. The main advantage of this approach is that the high level control (human synergies) is substantially independent from the robotic hand and depends only on the specific operation to be performed. It could then be possible, for example, to use the same controller with different robotic hands, or simply substitute a device without changing the controller, thus realizing a sort of abstraction layer for robotic hand control based on postural synergies.

References

G. Gioioso, G. Salvietti, M. Malvezzi, D. Prattichizzo. Mapping Synergies from Human to Robotic Hands with Dissimilar Kinematics: an Approach in the Object Domain. IEEE Trans. on Robotics, In press, 2013.

G. Gioioso, G. Salvietti, M. Malvezzi, D. Prattichizzo. An Object-Based Approach to Map Human Hand Synergies onto Robotic Hands with Dissimilar Kinematics. In Robotics: Science and Systems VIII, The MIT Press, Sidney, Australia, July 2012.

G. Gioioso, G. Salvietti, M. Malvezzi and P. Prattichizzo “Mapping synergies from human to robotic hands with dissimilar kinematics: an object based approach”, in Proc. of Workshop “Manipulation Under Uncertainty” International Conference on Robotics an Automation, ICRA 2011

Video

This video shows an application of the mapping algorithm in the EU funded experiment HANDS.DVI in the context of the ECHORD project.

In this video it is shown how the object-based mapping can be easily implemented in our Matlab Toolbox Syngrasp