Domenico Camboni

Piezoelectric Energy Harvesting Solutions

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.

Intraneural stimulation elicits discrimination of textural features by artificial fingertip in intact and amputee humans

Restoration of touch after hand amputation is a desirable feature of ideal prostheses. Here, we show that texture discrimination can be artificially provided in human subjects by implementing a neuromorphic real-time mechano-neuro-transduction (MNT), which emulates to some extent the firing dynamics of SA1 cutaneous afferents. The MNT process was used to modulate the temporal pattern of electrical spikes delivered to the human median nerve via percutaneous microstimulation in four intact subjects and via implanted intrafascicular stimulation in one transradial amputee. Both approaches allowed the subjects to reliably discriminate spatial coarseness of surfaces as confirmed also by a hybrid neural model of the median nerve. Moreover, MNT-evoked EEG activity showed physiologically plausible responses that were superimposable in time and topography to the ones elicited by a natural mechanical tactile stimulation. These findings can open up novel opportunities for sensory restoration in the next generation of neuro-prosthetic hands. DOI: http://dx.doi.org/10.7554/eLife.09148.001

Frontiers of robotic endoscopic capsules: a review

Digestive diseases are a major burden for society and healthcare systems, and with an aging population, the importance of their effective management will become critical. Healthcare systems worldwide already struggle to insure quality and affordability of healthcare delivery and this will be a significant challenge in the midterm future. Wireless capsule endoscopy (WCE), introduced in 2000 by Given Imaging Ltd., is an example of disruptive technology and represents an attractive alternative to traditional diagnostic techniques. WCE overcomes conventional endoscopy enabling inspection of the digestive system without discomfort or the need for sedation. Thus, it has the advantage of encouraging patients to undergo gastrointestinal (GI) tract examinations and of facilitating mass screening programmes. With the integration of further capabilities based on microrobotics, e.g. active locomotion and embedded therapeutic modules, WCE could become the key-technology for GI diagnosis and treatment. This review presents a research update on WCE and describes the state-of-the-art of current endoscopic devices with a focus on research-oriented robotic capsule endoscopes enabled by microsystem technologies. The article also presents a visionary perspective on WCE potential for screening, diagnostic and therapeutic endoscopic procedures.

Artificial spatiotemporal touch inputs reveal complementary decoding in neocortical neurons

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 input selectivity also between neighboring neurons. Such neuronal heterogeneity and complementariness can potentially support a very high decoding capacity in a limited population of neurons. Our results also indicate a potential neuroprosthetic approach to communicate with the brain at a very high resolution and provide a potential novel solution for evaluating the degree or state of neurological disease in animal models.

Real-Time Single Camera Hand Gesture Recognition System for Remote Deaf-Blind Communication

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.

A Bio-Hybrid Tactile Sensor Incorporating Living Artificial Skin and an Impedance Sensing Array

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.

Tactile piezoresistive sensors for robotic application: Design and metrological characterization

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.

Neuromorphic Artificial Sense of Touch: Bridging Robotics and Neuroscience

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.