Tactile explorations with the fingertips provide information regarding the physical properties of... more Tactile explorations with the fingertips provide information regarding the physical properties of surfaces and their relative pleasantness. Previously, we performed an investigation in the active touch domain and linked several surface properties (i.e. frictional force fluctuations and net friction) with their pleasantness levels. The aim of the present study was to investigate physical factors being important for pleasantness perception during passive fingertip stimulation. Specifically we were interested to see whether factors, such as surfaces' topographies or their frictional characteristics could influence pleasantness. Furthermore, we ascertained how the stimulus pleasantness level was impacted by (i) the normal force of stimulus application (F ) and (ii) the stimulus temperature (T ). 23h Archived Tweets
IEEE transactions on medical robotics and bionics, May 1, 2019
A major challenge in upper limb neuroprostheses is to reproduce the tactile feedback as the one p... more A major challenge in upper limb neuroprostheses is to reproduce the tactile feedback as the one provided by the spiking activity of human mechanoreceptors. In this study we aim at emulating the firing behaviour of Merkel mechanoreceptors, innervated by Slowly Adapting Type I (SA1) receptors, in silico by means of a custom implementation of the Izhikevich spiking neuron model with a porting function of the sensors output. We matched the neuron model output with the sustained firing observed in neurophysiological experiments in response to constant stimuli to the skin. We compared different input transformation functions to find the proper trade-off between agreement with biological spiking activity and model leanness. We identified a porting function that converts the output of physical sensors into the input to artificial spiking models of mechanoreceptors. The porting function was then validated by comparing the firing rate-indentation curve of real mechanoreceptors with the one obtained from a MEMS-based biomimetic tactile sensor platform. From the analysis of the adjusted-residual variance, the two curves result coherent. Therefore, having applied the calibration inverse function to a sensor output, the proposed porting function allows obtaining the proper input to an artificial neuron model, enabling the generation of neuromorphic signals.
Springer proceedings in advanced robotics, Jul 25, 2017
The development of a neuromorphic artificial sense of touch is presented. The system allows to co... more The development of a neuromorphic artificial sense of touch is presented. The system allows to code tactile information by means of a sequence of spikes, mimicking the neural dynamics of SA and FA human mechanoreceptors. The developed neuromorphic fingertip was able to encode naturalistic textures with a very high rate of disambiguation, up to 97% over a 10% chance level, by means of Victor-Purpura spike metrics and kNN decoding. A neurocomputational architecture inspired to the Cuneate Nucleus was also developed in order to achieve categorization of tactile stimuli in real-time while gathering the data stream. The implemented architecture was assessed by experimenting stimuli differing in the orientation of the tactile edges. The presented results are intended to contribute towards the restoration of a quasi-natural sense of touch in limb neuroprostheses, to develop effective and computationally lean artificial touch systems for robotic applications and to contribute to the open neuroscientific debate about the human somatosensory system.
Generalization ability in tactile sensing for robotic manipulation is a prerequisite to effective... more Generalization ability in tactile sensing for robotic manipulation is a prerequisite to effectively perform tasks in ever-changing environments. In particular, performing dynamic tactile perception is currently beyond the ability of robotic devices. A biomimetic approach to achieve this dexterity is to develop machines combining compliant robotic manipulators with neuroinspired architectures displaying computational adaptation. Here we demonstrate the feasibility of this approach for dynamic touch tasks experimented by integrating our sensing apparatus in a 6 degrees of freedom robotic arm via a soft wrist. We embodied in the system a model of spike-based neuromorphic encoding of tactile stimuli, emulating the discrimination properties of cuneate nucleus neurons based on pathways with differential delay lines. These strategies allowed the system to correctly perform a dynamic touch protocol of edge orientation recognition (ridges from 0 to 40 • , with a step of 5 • ). Crucially, the task was robust to contact noise and was performed with high performance irrespectively of sensing conditions (sensing forces and velocities). These results are a step forward toward the development of robotic arms able to physically interact in real-world environments with tactile sensing.
Hydrothermal growth of ZnO nanorods has been widely used for the development of tactile sensors, ... more Hydrothermal growth of ZnO nanorods has been widely used for the development of tactile sensors, with the aid of ZnO seed layers, favoring the growth of dense and vertically aligned nanorods. However, seed layers represent an additional fabrication step in the sensor design. In this study, a seedless hydrothermal growth of ZnO nanorods was carried out on Au-coated Si and polyimide substrates. The effects of both the Au morphology and the growth temperature on the characteristics of the nanorods were investigated, finding that smaller Au grains produced tilted rods, while larger grains provided vertical rods. Highly dense and high-aspect-ratio nanorods with hexagonal prismatic shape were obtained at 75 • C and 85 • C, while pyramid-like rods were grown when the temperature was set to 95 • C. Finite-element simulations demonstrated that prismatic rods produce higher voltage responses than the pyramid-shaped ones. A tactile sensor, with an active area of 1 cm 2 , was fabricated on flexible polyimide substrate and embedding the nanorods forest in a polydimethylsiloxane matrix as a separation layer between the bottom and the top Au electrodes. The prototype showed clear responses upon applied loads of 2-4 N and vibrations over frequencies in the range of 20-800 Hz.
Interest in tactile sensing technologies is advancing due to the growing adoption of robots in da... more Interest in tactile sensing technologies is advancing due to the growing adoption of robots in daily life activities. Human-machine interaction has thus to be safe, and collaborative robotics is becoming increasingly important. The present work features the design, development and preliminary validation of a soft large area sensor for tactile and proprioceptive sensing in a collaborative robotic manipulator. Such a manipulator is shaped to resemble the human hand and within this paper we focused on the index finger. The finger architecture has a design which allows setting up a structured 3D model, with flexible parametrization and fast prototyping. An optical fiber embedding 12 Fiber Bragg Gratings (FBGs) has been integrated in a soft polymeric matrix to mimic human sense of touch abilities of a whole finger. In order to assess the sensorized robotic manipulator, a mechatronic validation platform has been developed and employed. Preliminary results show a mechanical decoupling between exteroceptive and proprioceptive functions, and among the spatially distributed outputs of the sensor array. These results demonstrate the potential of the proposed approach towards achieving dexterous and fine capabilities in the manipulation of objects.
The development of a bio-hybrid tactile sensor array that incorporates a skin analogue comprised ... more The development of a bio-hybrid tactile sensor array that incorporates a skin analogue comprised of alginate encapsulated fibroblasts is described. The electrical properties are modulated by mechanical stress induced during contact, and changes are detected by a ten-channel dual-electrode impedance sensing array. By continuously monitoring the impedance of the sensor array at a fixed frequency, whilst normal and tangential loads are applied to the skin surface, transient mechanotransduction has been observed. The results demonstrate the effectiveness and feasibility of the preliminary prototype bio-hybrid tactile sensor.
This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basic... more This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions.
IEEE Transactions on Medical Robotics and Bionics, 2021
In this work, an endoscopic tactile robotic capsule embedding miniaturized MEMS force sensors is ... more In this work, an endoscopic tactile robotic capsule embedding miniaturized MEMS force sensors is presented. The capsule is conceived to provide automatic palpation of non-polypoid colorectal tumours during colonoscopic procedures, since they are characterized by a high degree of dysplasia, higher invasiveness and lower detection rates with respect to polyps. Methods: A first test was performed employing a silicone phantom that embedded a set of inclusions with variable hardness and curvature. In this scenario, a hardness-based classification was implemented, demonstrating detection robustness to curvature variation. By following a comparison of several well-known supervised classification algorithms, we chose a weighted 3-nearest neighbor classifier to detect the inclusions. We also introduced a bias force normalization model in order to make different acquisition sets consistent. The parameters of this model were chosen through a particle swarm optimization method. Additionally, an ex-vivo test was performed to assess the capsule detection performance when magnetically driven along a colonic tissue. An external permanent magnet positioned at the end-effector of an anthropomorphic robotic arm was used to drive the capsule. In this framework, lumps were identified as voltage peaks with a prominence depending on the total magnetic force applied to the capsule. Results: In a 94 % accuracy in hardness classification is achieved, while a 100% accuracy is obtained for the lump detection within a tolerance of 5 mm from the central path described by the capsule. Conclusion: In the real application scenario, we foresee our device aiding the physician to detect tumorous tissues.
This paper reviews automated visual-based defect detection approaches applicable to various mater... more This paper reviews automated visual-based defect detection approaches applicable to various materials, such as metals, ceramics and textiles. In the first part of the paper, we present a general taxonomy of the different defects that fall in two classes: visible (e.g., scratches, shape error, etc.) and palpable (e.g., crack, bump, etc.) defects. Then, we describe artificial visual processing techniques that are aimed at understanding of the captured scenery in a mathematical/logical way. We continue with a survey of textural defect detection based on statistical, structural and other approaches. Finally, we report the state of the art for approaching the detection and classification of defects through supervised and non-supervised classifiers and deep learning.
Humans rely on their sense of touch to interact with the environment. Thus, restoring lost tactil... more Humans rely on their sense of touch to interact with the environment. Thus, restoring lost tactile sensory capabilities in amputees would advance their quality of life. In particular, texture discrimination is an important component for the interaction with the environment, but its restoration in amputees has been so far limited to simplified gratings. Here we show that naturalistic textures can be discriminated by trans-radial amputees using intraneural peripheral stimulation and tactile sensors located close to the outer layer of the artificial skin. These sensors exploit the morphological neural computation (MNC) approach, i.e., the embodiment of neural computational functions into the physical structure of the device, encoding normal and shear stress to guarantee a faithful neural temporal representation of stimulus spatial structure. Two trans-radial amputees successfully discriminated naturalistic textures via the MNC-based tactile feedback. The results also allowed to shed li...
Investigations of the mechanisms of touch perception and decoding has been hampered by difficulti... more Investigations of the mechanisms of touch perception and decoding has been hampered by difficulties in achieving invariant patterns of skin sensor activation. To obtain reproducible spatiotemporal patterns of activation of sensory afferents, we used an artificial fingertip equipped with an array of neuromorphic sensors. The artificial fingertip was used to transduce real-world haptic stimuli into spatiotemporal patterns of spikes. These spike patterns were delivered to the skin afferents of the second digit of rats via an array of stimulation electrodes. Combined with low-noise intra- and extracellular recordings from neocortical neurons in vivo, this approach provided a previously inaccessible high resolution analysis of the representation of tactile information in the neocortical neuronal circuitry. The results indicate high information content in individual neurons and reveal multiple novel neuronal tactile coding features such as heterogeneous and complementary spatiotemporal in...
This paper reports the design and the development of a new bio-hybrid tactile sensor based on the... more This paper reports the design and the development of a new bio-hybrid tactile sensor based on the integration of canine kidney epithelial cells within an artificial device. Mechanical stimuli transduced by cells were detected via electrical measurements. In the long run, this novel bio-hybrid approach can pave the way to advanced hybrid sensors provided with self-healing properties and biomimetic compliance.
This paper presents a fast approach for marker-less Full-DOF hand tracking, leveraging only depth... more This paper presents a fast approach for marker-less Full-DOF hand tracking, leveraging only depth information from a single depth camera. This system can be useful in many applications, ranging from tele-presence to remote control of robotic actuators or interaction with 3D virtual environment. We applied the proposed technology to enable remote transmission of signs from Tactile Sing Languages (i.e., Sign Languages with Tactile feedbacks), allowing non-invasive remote communication not only among deaf-blind users, but also with deaf, blind and hearing with proficiency in Sign Languages. We show that our approach paves the way to a fluid and natural remote communication for deaf-blind people, up to now impossible. This system is a first prototype for the PARLOMA project, which aims at designing a remote communication system for deaf-blind people.
2017 IEEE International Conference on Cyborg and Bionic Systems (CBS)
To implement safety measures and to increase effectiveness of navigation in gastrointestinal endo... more To implement safety measures and to increase effectiveness of navigation in gastrointestinal endoscopy, we have integrated a dense array of MEMS tactile sensors in a magnetically-driven robotic endoscopic capsule. With traditional endoscopic probes, the force applied to the gastrointestinal wall cannot be directly measured and controlled. The presented sensorized capsule will allow implementing strategies for preventing tissue damages and thus pain, discomfort or even perforation during colonoscopy. The sensors embedded onto the here presented capsule will allow for online force readout and a closed-loop force control for real-time safety strategy has been implemented. Moreover, fine force readout will enhance capsule navigation, allowing optimization of the contact condition and thus diminishing friction with the endoluminal wall. The presented system will be tested in the future to prove capabilities as tactile tool for remote palpation, providing the physician with texture and stiffness information during endoscopic procedure.
Microfabricated tactile sensors gain importance for their application in bio-robotics. They are u... more Microfabricated tactile sensors gain importance for their application in bio-robotics. They are useful for the measurement of contact properties, in particular force and pressure, in three main fields, i.e., prosthetics and artificial skin, minimal access surgery and collaborative robotics. Among the different technological solutions, piezoresistive materials proved to be suitable for such an application. These materials show a change of electrical resistivity as a function of the applied strain. This work describes the design of a 2×2 array of piezoresistive elements and the experimental setup arranged for the array characterization, intended to be embedded within an artificial fingertip. The size of the bare array is 1.5×1.5×0.65 mm3. The finger has been designed to bio-mimic the behaviour of a human finger tip, thanks to the external layer of dragon skin. The static calibration of the sensors has been carried out by applying quasistatic normal loads on the mesa of each sensor of the array in two configurations (i.e., bare array and the array embedded in a fingertip). The sensors showed a linear response; the sensitivity ranges from 34 mV/N to 65 mV/N for the bare array, and from 16 mV/N to 39 mV/N for the array in the fingertip. No significant cross-talk (∼2%) has been observed during the test on the bare array. Further tests will be designed to characterize the response to tangential loads and assess the dynamic response of the sensors, as well as additional features which can be crucial for bio-robotic applications.
Continuous and reliable cardiac function monitoring could improve medication adherence in patient... more Continuous and reliable cardiac function monitoring could improve medication adherence in patients at risk of heart failure. This work presents an innovative implantable Fiber Bragg Grating-based soft sensor designed to sense mechanical cardiac activity. The sensor was tested in an isolated beating ovine heart platform, with 3 different hearts operated in wide-ranging conditions. In order to investigate the sensor capability to track the ventricular beats in real-time, two causal algorithms were proposed for detecting the beats from sensor data and to discriminate artifacts. The first based on dynamic thresholds while the second is a hybrid convolutional and recurrent Neural Network. An error of 2.7 ± 0.7 beats per minute was achieved in tracking the heart rate. Finally, we have confirmed the sensor reliability in monitoring the heart activity of healthy adult minipig with an error systematically lower than 1 Bpm.
Tactile explorations with the fingertips provide information regarding the physical properties of... more Tactile explorations with the fingertips provide information regarding the physical properties of surfaces and their relative pleasantness. Previously, we performed an investigation in the active touch domain and linked several surface properties (i.e. frictional force fluctuations and net friction) with their pleasantness levels. The aim of the present study was to investigate physical factors being important for pleasantness perception during passive fingertip stimulation. Specifically we were interested to see whether factors, such as surfaces' topographies or their frictional characteristics could influence pleasantness. Furthermore, we ascertained how the stimulus pleasantness level was impacted by (i) the normal force of stimulus application (F ) and (ii) the stimulus temperature (T ). 23h Archived Tweets
IEEE transactions on medical robotics and bionics, May 1, 2019
A major challenge in upper limb neuroprostheses is to reproduce the tactile feedback as the one p... more A major challenge in upper limb neuroprostheses is to reproduce the tactile feedback as the one provided by the spiking activity of human mechanoreceptors. In this study we aim at emulating the firing behaviour of Merkel mechanoreceptors, innervated by Slowly Adapting Type I (SA1) receptors, in silico by means of a custom implementation of the Izhikevich spiking neuron model with a porting function of the sensors output. We matched the neuron model output with the sustained firing observed in neurophysiological experiments in response to constant stimuli to the skin. We compared different input transformation functions to find the proper trade-off between agreement with biological spiking activity and model leanness. We identified a porting function that converts the output of physical sensors into the input to artificial spiking models of mechanoreceptors. The porting function was then validated by comparing the firing rate-indentation curve of real mechanoreceptors with the one obtained from a MEMS-based biomimetic tactile sensor platform. From the analysis of the adjusted-residual variance, the two curves result coherent. Therefore, having applied the calibration inverse function to a sensor output, the proposed porting function allows obtaining the proper input to an artificial neuron model, enabling the generation of neuromorphic signals.
Springer proceedings in advanced robotics, Jul 25, 2017
The development of a neuromorphic artificial sense of touch is presented. The system allows to co... more The development of a neuromorphic artificial sense of touch is presented. The system allows to code tactile information by means of a sequence of spikes, mimicking the neural dynamics of SA and FA human mechanoreceptors. The developed neuromorphic fingertip was able to encode naturalistic textures with a very high rate of disambiguation, up to 97% over a 10% chance level, by means of Victor-Purpura spike metrics and kNN decoding. A neurocomputational architecture inspired to the Cuneate Nucleus was also developed in order to achieve categorization of tactile stimuli in real-time while gathering the data stream. The implemented architecture was assessed by experimenting stimuli differing in the orientation of the tactile edges. The presented results are intended to contribute towards the restoration of a quasi-natural sense of touch in limb neuroprostheses, to develop effective and computationally lean artificial touch systems for robotic applications and to contribute to the open neuroscientific debate about the human somatosensory system.
Generalization ability in tactile sensing for robotic manipulation is a prerequisite to effective... more Generalization ability in tactile sensing for robotic manipulation is a prerequisite to effectively perform tasks in ever-changing environments. In particular, performing dynamic tactile perception is currently beyond the ability of robotic devices. A biomimetic approach to achieve this dexterity is to develop machines combining compliant robotic manipulators with neuroinspired architectures displaying computational adaptation. Here we demonstrate the feasibility of this approach for dynamic touch tasks experimented by integrating our sensing apparatus in a 6 degrees of freedom robotic arm via a soft wrist. We embodied in the system a model of spike-based neuromorphic encoding of tactile stimuli, emulating the discrimination properties of cuneate nucleus neurons based on pathways with differential delay lines. These strategies allowed the system to correctly perform a dynamic touch protocol of edge orientation recognition (ridges from 0 to 40 • , with a step of 5 • ). Crucially, the task was robust to contact noise and was performed with high performance irrespectively of sensing conditions (sensing forces and velocities). These results are a step forward toward the development of robotic arms able to physically interact in real-world environments with tactile sensing.
Hydrothermal growth of ZnO nanorods has been widely used for the development of tactile sensors, ... more Hydrothermal growth of ZnO nanorods has been widely used for the development of tactile sensors, with the aid of ZnO seed layers, favoring the growth of dense and vertically aligned nanorods. However, seed layers represent an additional fabrication step in the sensor design. In this study, a seedless hydrothermal growth of ZnO nanorods was carried out on Au-coated Si and polyimide substrates. The effects of both the Au morphology and the growth temperature on the characteristics of the nanorods were investigated, finding that smaller Au grains produced tilted rods, while larger grains provided vertical rods. Highly dense and high-aspect-ratio nanorods with hexagonal prismatic shape were obtained at 75 • C and 85 • C, while pyramid-like rods were grown when the temperature was set to 95 • C. Finite-element simulations demonstrated that prismatic rods produce higher voltage responses than the pyramid-shaped ones. A tactile sensor, with an active area of 1 cm 2 , was fabricated on flexible polyimide substrate and embedding the nanorods forest in a polydimethylsiloxane matrix as a separation layer between the bottom and the top Au electrodes. The prototype showed clear responses upon applied loads of 2-4 N and vibrations over frequencies in the range of 20-800 Hz.
Interest in tactile sensing technologies is advancing due to the growing adoption of robots in da... more Interest in tactile sensing technologies is advancing due to the growing adoption of robots in daily life activities. Human-machine interaction has thus to be safe, and collaborative robotics is becoming increasingly important. The present work features the design, development and preliminary validation of a soft large area sensor for tactile and proprioceptive sensing in a collaborative robotic manipulator. Such a manipulator is shaped to resemble the human hand and within this paper we focused on the index finger. The finger architecture has a design which allows setting up a structured 3D model, with flexible parametrization and fast prototyping. An optical fiber embedding 12 Fiber Bragg Gratings (FBGs) has been integrated in a soft polymeric matrix to mimic human sense of touch abilities of a whole finger. In order to assess the sensorized robotic manipulator, a mechatronic validation platform has been developed and employed. Preliminary results show a mechanical decoupling between exteroceptive and proprioceptive functions, and among the spatially distributed outputs of the sensor array. These results demonstrate the potential of the proposed approach towards achieving dexterous and fine capabilities in the manipulation of objects.
The development of a bio-hybrid tactile sensor array that incorporates a skin analogue comprised ... more The development of a bio-hybrid tactile sensor array that incorporates a skin analogue comprised of alginate encapsulated fibroblasts is described. The electrical properties are modulated by mechanical stress induced during contact, and changes are detected by a ten-channel dual-electrode impedance sensing array. By continuously monitoring the impedance of the sensor array at a fixed frequency, whilst normal and tangential loads are applied to the skin surface, transient mechanotransduction has been observed. The results demonstrate the effectiveness and feasibility of the preliminary prototype bio-hybrid tactile sensor.
This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basic... more This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions.
IEEE Transactions on Medical Robotics and Bionics, 2021
In this work, an endoscopic tactile robotic capsule embedding miniaturized MEMS force sensors is ... more In this work, an endoscopic tactile robotic capsule embedding miniaturized MEMS force sensors is presented. The capsule is conceived to provide automatic palpation of non-polypoid colorectal tumours during colonoscopic procedures, since they are characterized by a high degree of dysplasia, higher invasiveness and lower detection rates with respect to polyps. Methods: A first test was performed employing a silicone phantom that embedded a set of inclusions with variable hardness and curvature. In this scenario, a hardness-based classification was implemented, demonstrating detection robustness to curvature variation. By following a comparison of several well-known supervised classification algorithms, we chose a weighted 3-nearest neighbor classifier to detect the inclusions. We also introduced a bias force normalization model in order to make different acquisition sets consistent. The parameters of this model were chosen through a particle swarm optimization method. Additionally, an ex-vivo test was performed to assess the capsule detection performance when magnetically driven along a colonic tissue. An external permanent magnet positioned at the end-effector of an anthropomorphic robotic arm was used to drive the capsule. In this framework, lumps were identified as voltage peaks with a prominence depending on the total magnetic force applied to the capsule. Results: In a 94 % accuracy in hardness classification is achieved, while a 100% accuracy is obtained for the lump detection within a tolerance of 5 mm from the central path described by the capsule. Conclusion: In the real application scenario, we foresee our device aiding the physician to detect tumorous tissues.
This paper reviews automated visual-based defect detection approaches applicable to various mater... more This paper reviews automated visual-based defect detection approaches applicable to various materials, such as metals, ceramics and textiles. In the first part of the paper, we present a general taxonomy of the different defects that fall in two classes: visible (e.g., scratches, shape error, etc.) and palpable (e.g., crack, bump, etc.) defects. Then, we describe artificial visual processing techniques that are aimed at understanding of the captured scenery in a mathematical/logical way. We continue with a survey of textural defect detection based on statistical, structural and other approaches. Finally, we report the state of the art for approaching the detection and classification of defects through supervised and non-supervised classifiers and deep learning.
Humans rely on their sense of touch to interact with the environment. Thus, restoring lost tactil... more Humans rely on their sense of touch to interact with the environment. Thus, restoring lost tactile sensory capabilities in amputees would advance their quality of life. In particular, texture discrimination is an important component for the interaction with the environment, but its restoration in amputees has been so far limited to simplified gratings. Here we show that naturalistic textures can be discriminated by trans-radial amputees using intraneural peripheral stimulation and tactile sensors located close to the outer layer of the artificial skin. These sensors exploit the morphological neural computation (MNC) approach, i.e., the embodiment of neural computational functions into the physical structure of the device, encoding normal and shear stress to guarantee a faithful neural temporal representation of stimulus spatial structure. Two trans-radial amputees successfully discriminated naturalistic textures via the MNC-based tactile feedback. The results also allowed to shed li...
Investigations of the mechanisms of touch perception and decoding has been hampered by difficulti... more Investigations of the mechanisms of touch perception and decoding has been hampered by difficulties in achieving invariant patterns of skin sensor activation. To obtain reproducible spatiotemporal patterns of activation of sensory afferents, we used an artificial fingertip equipped with an array of neuromorphic sensors. The artificial fingertip was used to transduce real-world haptic stimuli into spatiotemporal patterns of spikes. These spike patterns were delivered to the skin afferents of the second digit of rats via an array of stimulation electrodes. Combined with low-noise intra- and extracellular recordings from neocortical neurons in vivo, this approach provided a previously inaccessible high resolution analysis of the representation of tactile information in the neocortical neuronal circuitry. The results indicate high information content in individual neurons and reveal multiple novel neuronal tactile coding features such as heterogeneous and complementary spatiotemporal in...
This paper reports the design and the development of a new bio-hybrid tactile sensor based on the... more This paper reports the design and the development of a new bio-hybrid tactile sensor based on the integration of canine kidney epithelial cells within an artificial device. Mechanical stimuli transduced by cells were detected via electrical measurements. In the long run, this novel bio-hybrid approach can pave the way to advanced hybrid sensors provided with self-healing properties and biomimetic compliance.
This paper presents a fast approach for marker-less Full-DOF hand tracking, leveraging only depth... more This paper presents a fast approach for marker-less Full-DOF hand tracking, leveraging only depth information from a single depth camera. This system can be useful in many applications, ranging from tele-presence to remote control of robotic actuators or interaction with 3D virtual environment. We applied the proposed technology to enable remote transmission of signs from Tactile Sing Languages (i.e., Sign Languages with Tactile feedbacks), allowing non-invasive remote communication not only among deaf-blind users, but also with deaf, blind and hearing with proficiency in Sign Languages. We show that our approach paves the way to a fluid and natural remote communication for deaf-blind people, up to now impossible. This system is a first prototype for the PARLOMA project, which aims at designing a remote communication system for deaf-blind people.
2017 IEEE International Conference on Cyborg and Bionic Systems (CBS)
To implement safety measures and to increase effectiveness of navigation in gastrointestinal endo... more To implement safety measures and to increase effectiveness of navigation in gastrointestinal endoscopy, we have integrated a dense array of MEMS tactile sensors in a magnetically-driven robotic endoscopic capsule. With traditional endoscopic probes, the force applied to the gastrointestinal wall cannot be directly measured and controlled. The presented sensorized capsule will allow implementing strategies for preventing tissue damages and thus pain, discomfort or even perforation during colonoscopy. The sensors embedded onto the here presented capsule will allow for online force readout and a closed-loop force control for real-time safety strategy has been implemented. Moreover, fine force readout will enhance capsule navigation, allowing optimization of the contact condition and thus diminishing friction with the endoluminal wall. The presented system will be tested in the future to prove capabilities as tactile tool for remote palpation, providing the physician with texture and stiffness information during endoscopic procedure.
Microfabricated tactile sensors gain importance for their application in bio-robotics. They are u... more Microfabricated tactile sensors gain importance for their application in bio-robotics. They are useful for the measurement of contact properties, in particular force and pressure, in three main fields, i.e., prosthetics and artificial skin, minimal access surgery and collaborative robotics. Among the different technological solutions, piezoresistive materials proved to be suitable for such an application. These materials show a change of electrical resistivity as a function of the applied strain. This work describes the design of a 2×2 array of piezoresistive elements and the experimental setup arranged for the array characterization, intended to be embedded within an artificial fingertip. The size of the bare array is 1.5×1.5×0.65 mm3. The finger has been designed to bio-mimic the behaviour of a human finger tip, thanks to the external layer of dragon skin. The static calibration of the sensors has been carried out by applying quasistatic normal loads on the mesa of each sensor of the array in two configurations (i.e., bare array and the array embedded in a fingertip). The sensors showed a linear response; the sensitivity ranges from 34 mV/N to 65 mV/N for the bare array, and from 16 mV/N to 39 mV/N for the array in the fingertip. No significant cross-talk (∼2%) has been observed during the test on the bare array. Further tests will be designed to characterize the response to tangential loads and assess the dynamic response of the sensors, as well as additional features which can be crucial for bio-robotic applications.
Continuous and reliable cardiac function monitoring could improve medication adherence in patient... more Continuous and reliable cardiac function monitoring could improve medication adherence in patients at risk of heart failure. This work presents an innovative implantable Fiber Bragg Grating-based soft sensor designed to sense mechanical cardiac activity. The sensor was tested in an isolated beating ovine heart platform, with 3 different hearts operated in wide-ranging conditions. In order to investigate the sensor capability to track the ventricular beats in real-time, two causal algorithms were proposed for detecting the beats from sensor data and to discriminate artifacts. The first based on dynamic thresholds while the second is a hybrid convolutional and recurrent Neural Network. An error of 2.7 ± 0.7 beats per minute was achieved in tracking the heart rate. Finally, we have confirmed the sensor reliability in monitoring the heart activity of healthy adult minipig with an error systematically lower than 1 Bpm.
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Papers by Calogero Oddo