Publications

@article{pinardi_comparing_2023,

title = {Comparing end-effector position and joint angle feedback for online robotic limb tracking},

author = { Mattia Pinardi and Alessia Noccaro and Luigi Raiano and Domenico Formica and Giovanni {Di Pino}},

url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0286566},

doi = {10.1371/journal.pone.0286566},

issn = {1932-6203},

year  = {2023},

date = {2023-06-01},

urldate = {2023-06-01},

journal = {PLOS ONE},

volume = {18},

number = {6},

pages = {e0286566},

abstract = {Somatosensation greatly increases the ability to control our natural body. This suggests that supplementing vision with haptic sensory feedback would also be helpful when a user aims at controlling a robotic arm proficiently. However, whether the position of the robot and its continuous update should be coded in a extrinsic or intrinsic reference frame is not known. Here we compared two different supplementary feedback contents concerning the status of a robotic limb in 2-DoFs configuration: one encoding the Cartesian coordinates of the end-effector of the robotic arm (i.e., Task-space feedback) and another and encoding the robot joints angles (i.e., Joint-space feedback). Feedback was delivered to blindfolded participants through vibrotactile stimulation applied on participants’ leg. After a 1.5-hour training with both feedbacks, participants were significantly more accurate with Task compared to Joint-space feedback, as shown by lower position and aiming errors, albeit not faster (i.e., similar onset delay). However, learning index during training was significantly higher in Joint space feedback compared to Task-space feedback. These results suggest that Task-space feedback is probably more intuitive and more suited for activities which require short training sessions, while Joint space feedback showed potential for long-term improvement. We speculate that the latter, despite performing worse in the present work, might be ultimately more suited for applications requiring long training, such as the control of supernumerary robotic limbs for surgical robotics, heavy industrial manufacturing, or more generally, in the context of human movement augmentation.},

note = {Publisher: Public Library of Science},

keywords = {Body limbs, Motion, Prosthetics, Robotics, Robots, Sensory perception, Vibration, Vision},

pubstate = {published},

tppubtype = {article}

}

@article{farina_roboticists_2023,

title = {Roboticists Want to Give You a Third Arm: Unused Bandwidth in Neurons Can be Tapped to Control Extra Limbs},

author = { Dario Farina and Etienne Burdet and Carsten Mehring and Jaime Ibáñez},

url = {https://doi.org/10.1109/MSPEC.2023.10061646},

doi = {10.1109/MSPEC.2023.10061646},

issn = {0018-9235},

year  = {2023},

date = {2023-03-01},

urldate = {2023-05-29},

journal = {IEEE Spectrum},

volume = {60},

number = {3},

pages = {22--46},

abstract = {Consider a surgeon performing a delicate operation, one that needs her expertise and steady hands—all three of them. As her two biological hands manip-ulate surgical instruments, a third robotic limb that's attached to her torso plays a supporting role. Or picture a construction worker who is thankful for his extra robotic hand as it braces the heavy beam he's fastening into place with his other two hands. Imagine wearing an exoskeleton that would let you handle multiple objects simultaneously, like Spiderman's Dr. Octopus. Or contemplate the out-there music a composer could write for a pianist who has 12 fingers to spread across the keyboard.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pena-perez_how_2023,

title = {How virtual and mechanical coupling impact bimanual tracking},

author = { Nuria Peña-Pérez and Jonathan Eden and Ekaterina Ivanova and Ildar Farkhatdinov and Etienne Burdet},

url = {https://journals.physiology.org/doi/full/10.1152/jn.00057.2022},

doi = {10.1152/jn.00057.2022},

issn = {0022-3077},

year  = {2023},

date = {2023-01-01},

urldate = {2023-09-08},

journal = {Journal of Neurophysiology},

volume = {129},

number = {1},

pages = {102–114},

abstract = {Download figureDownload PowerPoint},

note = {Publisher: American Physiological Society},

keywords = {bimanual, coupling, Redundancy, visuomotor tracking},

pubstate = {published},

tppubtype = {article}

}

@article{pena-perez_impact_2023,

title = {The Impact of Stiffness in Bimanual Versus Dyadic Interactions Requiring Force Exchange},

author = {Nuria Peña-Pérez and Sharah Abdul Mutalib and Jonathan Eden and Ildar Farkhatdinov and Etienne Burdet},

doi = {10.1109/TOH.2023.3274584},

issn = {2329-4051},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {IEEE Transactions on Haptics},

pages = {1–6},

abstract = {During daily activities, humans routinely manipulate objects bimanually or with the help of a partner. This work explored how bimanual and dyadic coordination modes are impacted by the object's stiffness, which conditions inter-limb haptic communication. For this, we recruited twenty healthy participants who performed a virtual task inspired by object handling, where we looked at the initiation of force exchange and its continued maintenance while tracking. Our findings suggest that while individuals and dyads displayed different motor behaviours, which may stem from the dyad's need to estimate their partner's actions, they exhibited similar tracking accuracy. For both coordination modes, increased stiffness resulted in better tracking accuracy and more correlated motions, but required a larger effort through increased average torque. These results suggest that stiffness may be a key consideration in applications such as rehabilitation, where bimanual or external physical assistance is often provided.},

note = {Conference Name: IEEE Transactions on Haptics},

keywords = {bimanual control, Force, Grasping, human-human interaction, Monitoring, object stiffness, Target tracking, Task analysis, Torque, Virtual object manipulation, Wrist},

pubstate = {published},

tppubtype = {article}

}

@article{wang_learning_2023,

title = {Learning to Assist Bimanual Teleoperation using Interval Type-2 Polynomial Fuzzy Inference},

author = { Ziwei Wang and Haolin Fei and Yanpei Huang and Quentin Rouxel and Bo Xiao and Zhibin Li and Etienne Burdet},

doi = {10.1109/TCDS.2023.3272730},

issn = {2379-8939},

year  = {2023},

date = {2023-01-01},

journal = {IEEE Transactions on Cognitive and Developmental Systems},

pages = {1–1},

abstract = {Assisting humans in collaborative tasks is a promising application for robots, however effective assistance remains challenging. In this paper, we propose a method for providing intuitive robotic assistance based on learning from human natural limb coordination. To encode coupling between multiple-limb motions, we use a novel interval type-2 (IT2) polynomial fuzzy inference for modeling trajectory adaptation. The associated polynomial coefficients are estimated using a modified recursive least-square with a dynamic forgetting factor. We propose to employ a Gaussian process to produce robust human motion predictions, and thus address the uncertainty and measurement noise of the system caused by interactive environments. Experimental results on two types of interaction tasks demonstrate the effectiveness of this approach, which achieves high accuracy in predicting assistive limb motion and enables humans to perform bimanual tasks using only one limb.},

note = {Conference Name: IEEE Transactions on Cognitive and Developmental Systems},

keywords = {Bimanual manipulation, Collaboration, Fuzzy sets, Gaussian process, Human-robot collaboration, IT2 polynomial fuzzy system, Robot kinematics, Robot learning, Robots, Task analysis, Trajectory, Uncertainty},

pubstate = {published},

tppubtype = {article}

}

@article{pinardi_exploring_2023,

title = {Exploring crossmodal correspondences for future research in human movement augmentation},

author = { Mattia Pinardi and Nicola {Di Stefano} and Giovanni {Di Pino} and Charles Spence},

url = {https://www.frontiersin.org/articles/10.3389/fpsyg.2023.1190103},

issn = {1664-1078},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {Frontiers in Psychology},

volume = {14},

abstract = {“Crossmodal correspondences” are the consistent mappings between perceptual dimensions or stimuli from different sensory domains, which have been widely observed in the general population and investigated by experimental psychologists in recent years. At the same time, the emerging field of human movement augmentation (i.e., the enhancement of an individual’s motor abilities by means of artificial devices) has been struggling with the question of how to relay supplementary information concerning the state of the artificial device and its interaction with the environment to the user, which may help the latter to control the device more effectively. To date, this challenge has not been explicitly addressed by capitalizing on our emerging knowledge concerning crossmodal correspondences, despite these being tightly related to multisensory integration. In this perspective paper, we introduce some of the latest research findings on the crossmodal correspondences and their potential role in human augmentation. We then consider three ways in which the former might impact the latter, and the feasibility of this process. First, crossmodal correspondences, given the documented effect on attentional processing, might facilitate the integration of device status information (e.g., concerning position) coming from different sensory modalities (e.g., haptic and visual), thus increasing their usefulness for motor control and embodiment. Second, by capitalizing on their widespread and seemingly spontaneous nature, crossmodal correspondences might be exploited to reduce the cognitive burden caused by additional sensory inputs and the time required for the human brain to adapt the representation of the body to the presence of the artificial device. Third, to accomplish the first two points, the benefits of crossmodal correspondences should be maintained even after sensory substitution, a strategy commonly used when implementing supplementary feedback.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{buratti_effect_2023,

title = {Effect of Vibrotactile Feedback on the Control of the Interaction Force of a Supernumerary Robotic Arm},

author = { Silvia Buratti and Davide Deiana and Alessia Noccaro and Mattia Pinardi and Giovanni {Di Pino} and Domenico Formica and Nathanaël Jarrassé},

url = {https://www.mdpi.com/2075-1702/11/12/1085},

doi = {10.3390/machines11121085},

issn = {2075-1702},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {Machines},

volume = {11},

number = {12},

abstract = {Supernumerary robotic limbs are mainly designed to augment the physical capabilities of able-bodied individuals, in a wide range of contexts from body support to surgery. When they are worn as wearable devices, they naturally provide inherent feedback due to the mechanical coupling with the human body. The user can, thus, perceive the interaction with the environment by relying on a combination of visual and inherent feedback. However, these can be inefficient in accomplishing complex tasks, particularly in the case of visual occlusion or variation in the environment stiffness. Here, we investigated whether, in a force-regulation task using a wearable supernumerary robotic arm (SRA), additional vibrotactile feedback can increase the control performance of participants compared to the inherent feedback. Additionally, to make the scenario more realistic, we introduced variations in the SRA’s kinematic posture and in the environment stiffness. Notably, our findings revealed a statistically significant improvement in user performance over all the evaluated metrics while receiving additional vibrotactile feedback. Compared to inherent feedback alone, the additional vibrotactile feedback allowed participants to exert the required force faster (p < 0.01), to maintain it for longer (p < 0.001), and with lower errors (p < 0.001). No discernible effects related to the SRA’s posture or environment stiffness were observed. These results proved the benefits of providing the user with additional vibrotactile feedback to convey the SRA’s force during interaction tasks.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{eden_principles_2022,

title = {Principles of human movement augmentation and the challenges in making it a reality},

author = {Jonathan Eden and Mario Bräcklein and Jaime Ibáñez and Deren Yusuf Barsakcioglu and Giovanni {Di Pino} and Dario Farina and Etienne Burdet and Carsten Mehring},

doi = {10.1038/s41467-022-28725-7},

year  = {2022},

date = {2022-12-01},

urldate = {2022-12-01},

journal = {Nature Communications},

volume = {13},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{di_stefano_ethics_2022b,

title = {The Ethics of Supernumerary Robotic Limbs. An Enactivist Approach},

author = { Nicola {Di Stefano} and Nathanaël Jarrassé and Luca Valera},

url = {https://doi.org/10.1007/s11948-022-00405-1},

doi = {10.1007/s11948-022-00405-1},

issn = {1471-5546},

year  = {2022},

date = {2022-11-01},

urldate = {2022-11-01},

journal = {Science and Engineering Ethics},

volume = {28},

number = {6},

pages = {57},

abstract = {Supernumerary robotic limbs are innovative devices in the field of wearable robotics which can provide humans with unprecedented sensorimotor abilities. However, scholars have raised awareness of the ethical issues that would arise from the large adoption of technologies for human augmentation in society. Most negative attitudes towards such technologies seem to rely on an allegedly clear distinction between therapy and enhancement in the use of technological devices. Based on such distinction, people tend to accept technologies when used for therapeutic purposes (e.g., prostheses), but tend to raise issues when similar devices are used for upgrading a physical or cognitive ability (e.g., supernumerary robotics limbs). However, as many scholars have pointed out, the distinction between therapy and enhancement might be theoretically flawed. In this paper, we present an alternative approach to the ethics of supernumerary limbs which is based on two related claims. First, we propose to conceive supernumerary limbs as tools that necessarily modify our psychological and bodily identity. At the same time, we stress that such a modification is not ethically bad in itself; on the contrary, it drives human interaction with the environment. Second, by comparing our view with the extended mind thesis, we claim that the mediation through tools is crucial for the formation of novel meanings and skills that constitute human interaction with the world. We will relate the latter claim to enactivism as a helpful theoretical perspective to frame issues related to artificial limbs and, more in general, to technologies for augmentation. Based on this approach, we finally sketch some suggestions for future directions in the ethics of supernumerary limbs.},

keywords = {Enactivism, Human augmentation, Human enhancement, Motor augmentation, Wearable robotics},

pubstate = {published},

tppubtype = {article}

}

@article{pena_perez_is_2022,

title = {Is a Robot Needed to Modify Human Effort in Bimanual Tracking?},

author = {Nuria Peña-Pérez and Jonathan Eden and Ekaterina Ivanova and Etienne Burdet and Ildar Farkhatdinov},

doi = {10.1109/LRA.2022.3183753},

issn = {2377-3766},

year  = {2022},

date = {2022-07-01},

urldate = {2022-07-01},

journal = {IEEE Robotics and Automation Letters},

volume = {7},

number = {3},

pages = {8069–8075},

abstract = {Robotic bimanual training can benefit from understanding how to modify human motor effort in bimanual tasks. We addressed this issue by carrying out a study to investigate whether and how penalizing the use of one hand could alter the hands’ effort distribution. Actuated haptic perturbations and alterations of the visual feedback of the right hand were tested on a bimanual tracking task with 16 healthy right-handed participants. For each feedback modality (haptic or visual), both a disturbance and a perturbation requiring additional effort from the right hand were implemented. The results showed that the participants were able to adjust to these four perturbations, and perceived them correctly as something that disturbed the dominant hand. Contrary to our expectations, the bimanual effort distribution changes induced by the haptic perturbations were not uniform across subjects. However, the visual disturbance induced most participants to use only their unperturbed left hand (with only 2/16 participants reporting a different behaviour). This suggests that a visual disturbance could be used to alter the effort distribution among the two hands. Clinical validation of these findings on hemiplegic patients may help simplify the design of robotic training interfaces.},

note = {Conference Name: IEEE Robotics and Automation Letters},

keywords = {design and human factors, Haptic interfaces, human-centered robo- tics, Perturbation methods, Rehabilitation robotics, Robots, Task analysis, Training, Visualization, Wrist},

pubstate = {published},

tppubtype = {article}

}

@article{bracklein_control_2022,

title = {The control and training of single motor units in isometric tasks are constrained by a common input signal},

author = { Mario Bräcklein and Deren Yusuf Barsakcioglu and Jaime Ibáñez and Jonathan Eden and Etienne Burdet and Carsten Mehring and Dario Farina},

editor = { J Andrew Pruszynski and Tirin Moore and Andrew Fuglevand},

url = {https://doi.org/10.7554/eLife.72871},

doi = {10.7554/eLife.72871},

issn = {2050-084X},

year  = {2022},

date = {2022-06-01},

urldate = {2023-09-08},

journal = {eLife},

volume = {11},

pages = {e72871},

abstract = {Recent developments in neural interfaces enable the real-time and non-invasive tracking of motor neuron spiking activity. Such novel interfaces could provide a promising basis for human motor augmentation by extracting potentially high-dimensional control signals directly from the human nervous system. However, it is unclear how flexibly humans can control the activity of individual motor neurons to effectively increase the number of degrees of freedom available to coordinate multiple effectors simultaneously. Here, we provided human subjects (N = 7) with real-time feedback on the discharge patterns of pairs of motor units (MUs) innervating a single muscle (tibialis anterior) and encouraged them to independently control the MUs by tracking targets in a 2D space. Subjects learned control strategies to achieve the target-tracking task for various combinations of MUs. These strategies rarely corresponded to a volitional control of independent input signals to individual MUs during the onset of neural activity. Conversely, MU activation was consistent with a common input to the MU pair, while individual activation of the MUs in the pair was predominantly achieved by alterations in de-recruitment order that could be explained by history-dependent changes in motor neuron excitability. These results suggest that flexible MU recruitment based on independent synaptic inputs to single MUs is unlikely, although de-recruitment might reflect varying inputs or modulations in the neuron’s intrinsic excitability.},

note = {Publisher: eLife Sciences Publications, Ltd},

keywords = {common synaptic input, motor control, motor unit, real-time decomposition},

pubstate = {published},

tppubtype = {article}

}

@article{huang_identification_2022,

title = {Identification of Multiple Limbs Coordination Strategies in a Three-Goal Independent Task},

author = { Yanpei Huang and Ekaterina Ivanova and Jonathan Eden and Etienne Burdet},

doi = {10.1109/TMRB.2021.3124263},

issn = {2576-3202},

year  = {2022},

date = {2022-05-01},

journal = {IEEE Transactions on Medical Robotics and Bionics},

volume = {4},

number = {2},

pages = {348–351},

abstract = {Many surgical tasks require three or more tools operating together. A supernumerary robotic arm under the surgeon’s control could enable one surgeon to control three surgical tools simultaneously without assistance, thereby avoiding the common communication errors of the operation room. However, how do humans consider the complexity of controlling more than two arms together? In this paper, the coordination strategy used during three limb independent motion tasks is studied. The level of coordination increased over a two-day pilot study, and the resulting coordination pattern was in general consistent within subjects. Whether the subject used a fixed order of targets or a random sequence was found to reduce the improvement of pattern consistency after practice. The foot-controlled third hand exhibited less consistent patterns.},

note = {Conference Name: IEEE Transactions on Medical Robotics and Bionics},

keywords = {Analysis of variance, foot control, Measurement, Random sequences, Robot kinematics, Robots, Surgery, Task analysis, teleoperation, three-hand surgery, Tri-manipulation},

pubstate = {published},

tppubtype = {article}

}

@article{bracklein_reading_2022,

title = {Reading and Modulating Cortical β Bursts from Motor Unit Spiking Activity},

author = { Mario Bräcklein and Deren Yusuf Barsakcioglu and Alessandro Del Vecchio and Jaime Ibáñez and Dario Farina},

url = {https://www.jneurosci.org/content/42/17/3611},

doi = {10.1523/JNEUROSCI.1885-21.2022},

issn = {0270-6474, 1529-2401},

year  = {2022},

date = {2022-04-01},

urldate = {2022-04-01},

journal = {Journal of Neuroscience},

volume = {42},

number = {17},

pages = {3611–3621},

abstract = {β Oscillations (13–30 Hz) are ubiquitous in the human motor nervous system. Yet, their origins and roles are unknown. Traditionally, β activity has been treated as a stationary signal. However, recent studies observed that cortical β occurs in “bursting events,” which are transmitted to muscles. This short-lived nature of β events makes it possible to study the main mechanism of β activity found in the muscles in relation to cortical β. Here, we assessed whether muscle β activity mainly results from cortical projections. We ran two experiments in healthy humans of both sexes (N = 15 and N = 13, respectively) to characterize β activity at the cortical and motor unit (MU) levels during isometric contractions of the tibialis anterior muscle. We found that β rhythms observed at the cortical and MU levels are indeed in bursts. These bursts appeared to be time-locked and had comparable average durations (40–80 ms) and rates (approximately three to four bursts per second). To further confirm that cortical and MU β have the same source, we used a novel operant conditioning framework to allow subjects to volitionally modulate MU β. We showed that volitional modulation of β activity at the MU level was possible with minimal subject learning and was paralleled by similar changes in cortical β activity. These results support the hypothesis that MU β mainly results from cortical projections. Moreover, they demonstrate the possibility to decode cortical β activity from MU recordings, with a potential translation to future neural interfaces that use peripheral information to identify and modulate activity in the central nervous system. 

SIGNIFICANCE STATEMENT We show for the first time that β activity in motor unit (MU) populations occurs in bursting events. These bursts observed in the output of the spinal cord appear to be time-locked and share similar characteristics of β activity at the cortical level, such as the duration and rate at which they occur. Moreover, when subjects were exposed to a novel operant conditioning paradigm and modulated MU β activity, cortical β activity changed in a similar way as peripheral β. These results provide evidence for a strong correspondence between cortical and peripheral β activity, demonstrating the cortical origin of peripheral β and opening the pathway for a new generation of neural interfaces.},

note = {Publisher: Society for Neuroscience 

Section: Research Articles},

keywords = {Motor Units, neural interfaces, neural oscillations, real-time decomposition, β oscillations},

pubstate = {published},

tppubtype = {article}

}

@article{noauthor_abstracts_2022,

title = {Abstracts from the IFESS 2021 conferences - Design of multi‐pad electrotactile system envisioned as a feedback channel for supernumerary robotic limbs},

author = {Tanja Boljanić and Milica Isaković and Jovana Malešević and Domenico Formica and Giovanni {Di Pino} and Thierry Keller and Matija Štrbac},

url = {https://onlinelibrary.wiley.com/doi/10.1111/aor.14132},

doi = {10.1111/aor.14132},

issn = {0160-564X, 1525-1594},

year  = {2022},

date = {2022-03-01},

urldate = {2022-03-01},

journal = {Artificial Organs},

volume = {46},

number = {3},

pages = {36--41},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{boljanic_design_2022,

title = {Design of multi-pad electrotactile system envisioned as a feedback channel for supernumerary robotic limbs},

author = { Tanja Boljanić and Milica Isaković and Jovana Malešević and Domenico Formica and Giovanni {Di Pino} and Thierry Keller and Matija Štrbac},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/aor.14339},

doi = {10.1111/aor.14339},

issn = {1525-1594},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Artificial Organs},

volume = {46},

number = {10},

pages = {2034–2043},

abstract = {Background Providing real-time haptic feedback is an important, but still not sufficiently explored aspect of the use of supernumerary robotic limbs (SRLs). We present a multi-pad electrode for conveying multi-modal proprioceptive and sensory information from SRL to the user's thigh and propose a method for stimuli calibration. Methods Within two pilot tests, we investigated return electrode configuration and active electrode discrimination in three healthy subjects to select the appropriate electrode pad topology. Based on the obtained results and anthropometric data from the literature, the electrode was designed to have three branches of 10 pads and two additional pads that can be displaced over/under the electrode branches. The electrode was designed to be connected to the stimulator that allows full multiplexing so that specific branches can serve as a common return electrode. To define the procedure for application of this system, the sensation, localization, and discomfort thresholds applicable for the novel electrode were determined and analyzed in 10 subjects. Results The results showed no overlaps between the three thresholds for individual pads, with significantly different average values, suggesting that the selected electrode positioning and design provide a good active range of useful current amplitude. The results of the subsequent analysis suggested that the stimuli intensity level of 200% of the sensation threshold is the most probable value of the localization threshold. Furthermore, this level ensures a low chance (i.e., 0.7%) of reaching the discomfort. Conclusions We believe that envisioned electrotactile system could serve as a high bandwidth feedback channel that can be easily set up to provide proprioceptive and sensory feedback from supernumerary limbs.},

note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/aor.14339},

keywords = {electrotactile stimulation, multi-pad electrode, supernumerary robotic limb, tactile feedback},

pubstate = {published},

tppubtype = {article}

}

@article{khoramshahi_identification_2022b,

title = {Identification of inverse kinematic parameters in redundant systems: Towards quantification of inter-joint coordination in the human upper extremity},

author = { Mahdi Khoramshahi and Agnes Roby-Brami and Ross Parry and Nathanaël Jarrassé},

url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0278228},

doi = {10.1371/journal.pone.0278228},

issn = {1932-6203},

year  = {2022},

date = {2022-01-01},

urldate = {2024-02-12},

journal = {PLOS ONE},

volume = {17},

number = {12},

pages = {e0278228},

abstract = {Understanding and quantifying inter-joint coordination is valuable in several domains such as neurorehabilitation, robot-assisted therapy, robotic prosthetic arms, and control of supernumerary arms. Inter-joint coordination is often understood as a consistent spatiotemporal relation among kinematically redundant joints performing functional and goal-oriented movements. However, most approaches in the literature to investigate inter-joint coordination are limited to analysis of the end-point trajectory or correlation analysis of the joint rotations without considering the underlying task; e.g., creating a desirable hand movement toward a goal as in reaching motions. This work goes beyond this limitation by taking a model-based approach to quantifying inter-joint coordination. More specifically, we use the weighted pseudo-inverse of the Jacobian matrix and its associated null-space to explain the human kinematics in reaching tasks. We propose a novel algorithm to estimate such Inverse Kinematics weights from observed kinematic data. These estimated weights serve as a quantification for spatial inter-joint coordination; i.e., how costly a redundant joint is in its contribution to creating an end-effector velocity. We apply our estimation algorithm to datasets obtained from two different experiments. In the first experiment, the estimated Inverse Kinematics weights pinpoint how individuals change their Inverse Kinematics strategy when exposed to the viscous field wearing an exoskeleton. The second experiment shows how the resulting Inverse Kinematics weights can quantify a robotic prosthetic arm’s contribution (or the level of assistance).},

note = {Publisher: Public Library of Science},

keywords = {Body weight, Hip, Kinematics, Prosthetics, Robotics, Shoulders, Skeletal joints, Velocity},

pubstate = {published},

tppubtype = {article}

}

@article{noccaro_human_2021,

title = {Human performance in three-hands tasks},

author = {Alessia Noccaro and Jonathan Eden and Giovanni {Di Pino} and Domenico Formica and Etienne Burdet},

url = {http://www.nature.com/articles/s41598-021-88862-9},

doi = {10.1038/s41598-021-88862-9},

issn = {2045-2322},

year  = {2021},

date = {2021-12-01},

urldate = {2021-12-01},

journal = {Scientific Reports},

volume = {11},

number = {1},

pages = {9511},

abstract = {Abstract 

 

 The successful completion of complex tasks like hanging a picture or laparoscopic surgery requires coordinated motion of more than two limbs. User-controlled supernumerary robotic limbs (SL) have been proposed to bypass the need for coordination with a partner in such tasks. However, neither the capability to control multiple limbs alone relative to collaborative control with partners, nor how that capability varies across different tasks, is well understood. In this work, we present an investigation of tasks requiring three-hands where the foot was used as an additional source of motor commands. We considered: (1) how does simultaneous control of three hands compare to a cooperating dyad; (2) how this relative performance was altered by the existence of constraints emanating from real or virtual physical connections ( 

 mechanical constraints 

 ) or from cognitive limits ( 

 cognitive constraints 

 ). It was found that a cooperating dyad outperformed a single user in all scenarios in terms of task score, path efficiency and motion smoothness. However, while the participants were able to reach more targets with increasing mechanical constraints/decreasing number of simultaneous goals, the relative difference in performance between a dyad and a participant performing trimanual activities decreased, suggesting further potential for SLs in this class of scenario.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{huang_three-limb_2021,

title = {A Three-Limb Teleoperated Robotic System with Foot Control for Flexible Endoscopic Surgery},

author = {Yanpei Huang and Wenjie Lai and Lin Cao and Jiajun Liu and Xiaoguo Li and Etienne Burdet and Soo Jay Phee},

url = {https://link.springer.com/10.1007/s10439-021-02766-3},

doi = {10.1007/s10439-021-02766-3},

issn = {0090-6964, 1573-9686},

year  = {2021},

date = {2021-09-01},

urldate = {2022-06-02},

journal = {Annals of Biomedical Engineering},

volume = {49},

number = {9},

pages = {2282--2296},

keywords = {},

pubstate = {published},

tppubtype = {article}

}