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Targeted neurotechnology restores walking in humans with spinal cord injury

Authors: Wagner, Fabien B.; Mignardot, Jean-Baptiste; Le Goff-Mignardot, Camille G.; Demesmaeker, Robin; Komi, Salif; Capogrosso, Marco; Rowald, Andreas; Seáñez, Ismael; Caban, Miroslav; Pirondini, Elvira; Vat, Molywan; McCracken, Laura A.; Heimgartner, Roman; Fodor, Isabelle; Watrin, Anne; Seguin, Perrine; Paoles, Edoardo; Van Den Keybus, Katrien; Eberle, Grégoire; Schurch, Brigitte; Pralong, Etienne; Becce, Fabio; Prior, John; Buse, Nicholas; Buschman, R.; Neufeld, E.; Kuster, N.; Carda, S.; von Zitzwitz, J.; Delattre, V.; Denison, T.; Lambert, H.; Minassian, K.; Bloch, J.; Courtine, Grégoire

 

Spinal cord injury leads to severe locomotor deficits or even complete leg paralysis. Here we introduce targeted spinal cord stimulation neurotechnologies that enabled voluntary control of walking in individuals who had sustained a spinal cord injury more than four years ago and presented with permanent motor deficits or complete paralysis despite extensive rehabilitation. Using an implanted pulse generator with real-time triggering capabilities, we delivered trains of spatially selective stimulation to the lumbosacral spinal cord with timing that coincided with the intended movement. Within one week, this spatiotemporal stimulation had re-established adaptive control of paralysed muscles during overground walking. Locomotor performance improved during rehabilitation. After a few months, participants regained voluntary control over previously paralysed muscles without stimulation and could walk or cycle in ecological settings during spatiotemporal stimulation. These results establish a technological framework for improving neurological recovery and supporting the activities of daily living after spinal cord injury.

Reference

Posted on: September 3, 2019

Soft Haptic Device to Render the Sensation of Flying Like a Drone

Authors: Last-name, H.; Martinez-Carranza, J.;

 

Haptic feedback located on the torso is proposed to enhance the state awareness of a user in virtual reality or during teleoperation while leaving the hands free for manipulation and communication. We provide haptic feedback on the torso by compressing a set of closed air pouches against the skin in order to render the sensation of air pressure when piloting a drone. The pouch devices are cable driven and integrated in a wearable soft exoskeleton, called the FlyJacket. A mechanical model and simulation of a pouch device were developed in order to determine appropriate parameters, including the air pouch inner pressure, its attachment point, and the cable position. Using the simulation results, a set of pouch devices were constructed and integrated into the soft exoskeleton on both sides of the upper chest and middle of the back. The mechanical performance of the constructed device is close to that predicted by the simulation. Application of the haptic device in a flight task in which the user controls a drone using upper body movements was demonstrated with a user study. Adding haptic feedback during a stabilization task reduced the user’s workload and improved the state awareness of the user.

Reference

  • Published in: dd (Volume: xx, Issue: xx, April, 2019)
  • Detailed record: dd
  • DOI: dd
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  • Date: 2019
Posted on: September 3, 2019

Six-Month Assessment of a Hand Prosthesis with Intraneural Tactile Feedback Hand Prosthesis

Authors: Petrini, Francesco M.; Valle, Giacomo; Strauss, Ivo; Granata, Giuseppe; Di Iorio, Riccardo; D’Anna, Edoardo; Čvančara, Paul; Mueller, Matthias; Carpaneto, Jacopo; Clemente, Francesco; Controzzi, Marco; Bisoni, Lorenzo; Carboni, Caterina; Barbaro, Massimo; Iodice, Francesco; Andreu, David; Hiairrassary, Arthur; Divoux, Jean-Louis; Cipriani, Christian; Guiraud, David; Raffo, Luigi; Fernandez, Eduardo; Stieglitz, Thomas; Raspopovic, Stanisa; et al.

 

Objective
Hand amputation is a highly disabling event, which significantly affects quality of life. An effective hand replacement can be achieved if the user, in addition to motor functions, is provided with the sensations that are naturally perceived while grasping and moving. Intraneural peripheral electrodes have shown promising results toward the restoration of the sense of touch. However, the long‐term usability and clinical relevance of intraneural sensory feedback have not yet been clearly demonstrated.

Methods
To this aim, we performed a 6‐month clinical study with 3 transradial amputees who received implants of transverse intrafascicular multichannel electrodes (TIMEs) in their median and ulnar nerves. After calibration, electrical stimulation was delivered through the TIMEs connected to artificial sensors in the digits of a prosthesis to generate sensory feedback, which was then used by the subjects while performing different grasping tasks.

Results
All subjects, notwithstanding their important clinical differences, reported stimulation‐induced sensations from the phantom hand for the whole duration of the trial. They also successfully integrated the sensory feedback into their motor control strategies while performing experimental tests simulating tasks of real life (with and without the support of vision). Finally, they reported a decrement of their phantom limb pain and a general improvement in mood state.

Interpretation
The promising results achieved with all subjects show the feasibility of the use of intraneural stimulation in clinical settings.

Reference

  • Published in: Annals of Neurology (Volume: 85, Issue: 1, April, 2019
  • DOI: 10.1002/ana.25384
  • Date: 2018
Posted on: September 3, 2019

Single chamber multiple degree-of-freedom soft pneumatic actuator enabled by adjustable stiffness layers

Authors: Santoso, Junius; Skorina, Erik H; Salerno, Marco; de Rivaz, Sébastien; Paik, Jamie; Onal, Cagdas D

 

Soft pneumatic actuators promise simple, adaptable, and safe manipulation, but the nature of pneumatic circuits limits the scalability of this approach. This paper introduces a method to augment the degrees-of-freedom of soft pneumatic actuators without increasing the number of independent pressure sources or complex valving networks. Our method achieves multiple degree-of-freedom actuation from a single soft pneumatic chamber by utilizing adjustable stiffness layers based on a thermoplastic polyurethane shape memory polymer (SMP), which changes stiffness when thermally activated. We incorporate SMP layers into a soft pneumatic actuator, allowing multiple degrees of soft deformation to be achieved from a single pressure source by selective activation of SMP layers. A custom printed circuit board acts as a control unit to modularize and enable closed-loop control of the proposed pneumatic actuator. We validated our proposed system and method by varying the temperature of the SMP layer on one side of the actuator while keeping the other side stable near room temperature and observed an increase in bending angle of the pneumatic actuator as a function of temperature. Furthermore, we connected two actuators in series and demonstrated independent actuation, allowing the actuators to form different shapes with a single pressure source. Our results show that the proposed method can augment the degrees of freedom of soft pneumatic actuators as an alternative to multi-chamber or multi-valve systems.

Reference

  • Published in: Smart Materials and Structures (Volume: 28, Issue: 3, February, 2019)
  • DOI: 10.1088/1361-665X/aaf9c0
  • Date: 2019
Posted on: September 3, 2019

SegMap: Segment-based mapping and localization using data-driven descriptors

Authors: Dubé, Renaud; Cramariuc, Andrei; Dugas, Daniel; Sommer, Hannes; Dymczyk, Marcin; Nieto, Juan; Siegwart, Roland; Cadena, Cesar

 

Precisely estimating a robot’s pose in a prior, global map is a fundamental capability for mobile robotics, e.g., autonomous driving or exploration in disaster zones. This task, however, remains challenging in unstructured, dynamic environments, where local features are not discriminative enough and global scene descriptors only provide coarse information. We therefore present SegMap: a map representation solution for localization and mapping based on the extraction of segments in 3D point clouds. Working at the level of segments offers increased invariance to view-point and local structural changes, and facilitates real-time processing of large-scale 3D data. SegMap exploits a single compact data-driven descriptor for performing multiple tasks: global localization, 3D dense map reconstruction, and semantic information extraction. The performance of SegMap is evaluated in multiple urban driving and search and rescue experiments. We show that the learned SegMap descriptor has superior segment retrieval capabilities, compared with state-of-the-art handcrafted descriptors. As a consequence, we achieve a higher localization accuracy and a 6% increase in recall over state-of-the-art handcrafted descriptors. These segment-based localizations allow us to reduce the open-loop odometry drift by up to 50%. SegMap is open-source available along with easy to run demonstrations.

Reference

Posted on: September 3, 2019

RoboScallop: A Bivalve Inspired Swimming Robot

Authors: Robertson, Matthew A.; Efremov, Filip; Paik, Jamie

 

Underwater swimming robots permit remote access to over 70% of the Earth’s surface that is covered in water for a variety of scientific, environmental, tactical, or industrial purposes. Many practical applications for robots in this setting include sensing, monitoring, exploration, reconnaissance, or inspection tasks. In the interest of expanding this activity and opportunity within aquatic environments, this letter describes the development of a swimming robot characterized by simple, robust, and scalable design. The robot, named RoboScallop, is inspired by the locomotion of bivalve scallops, utilizing two articulating rigid shell components and a soft elastic membrane to produce water jet propulsion. A single-DoF, reciprocating crank mechanism enclosed within the shell housing of the robot is used to generate pulsating thrust, and the performance of this novel swimming method is evaluated by characterization of the robot jet force and swimming speed. This is the first time jet propulsion is demonstrated for a robot swimming in normal, Newtonian fluid using a bivalve morphology. We found the metrics of the robot to be comparable to its biological counterpart, but free from metabolic limitations which prevent sustained free swimming in living species. Leveraging this locomotion principle may provide unique benefits over other existing underwater propulsion techniques, including robustness, scalability, resistance to entanglement, and possible implicit water treatment capabilities, to drive the further development of a new class of self-contained, hybrid-stiffness underwater robots.

Reference

  • Published in: EEE Robotics and Automation Letters (Volume: 4, Issue: 2, April 2019)
  • DOI: 10.1109/LRA.2019.2897144
  • Date: 2019
Posted on: September 3, 2019