Massimo Totaro - Academia.edu (original) (raw)

Papers by Massimo Totaro

Electronic Skin, Sep 1, 2022

2022 IEEE Applied Power Electronics Conference and Exposition (APEC)

IEEE-ASME Transactions on Mechatronics, 2022

In this article, we present a reconstruction method for mapping a wide range of pressure stimuli ... more In this article, we present a reconstruction method for mapping a wide range of pressure stimuli in a multitouch soft optical waveguide skin (MSOWS). Distributed sensing information is typically obtained from wired soft sensing units. This approach hardly adapts to different shapes and has limited durability against stresses and shocks. In our MSOWS, the spatial tactile transduction relies on a continuum sensitive area of graded-stiffness polydimethylsiloxane, with a virtual grid free from electronics and connections. The sensing range of each cell is up to 234 kPa, and the spatial resolution is 5 mm. We use a time-delay neural network to reduce the hysteresis of the soft material to less than 1%. In addition, a fault-tolerant mechanism makes the entire system robust to component failure. These results may open the way to a new generation of distributed soft skins that are versatile due to material design and processing.

PLOS ONE, 2021

Pneumatic artificial muscles (PAMs) are one of the key technologies in soft robotics, and they en... more Pneumatic artificial muscles (PAMs) are one of the key technologies in soft robotics, and they enable actuation in mobile robots, in wearable devices and exoskeletons for assistive and rehabilitative purposes. While they recently showed relevant improvements, they still present quite low payload, limited bandwidth, and lack of repeatability, controllability and robustness. Vacuum-based actuation has been recently demonstrated as a very promising solution, and many challenges are still open, like generating at the same time a large contraction ratio, and a high blocking force with enhanced axial stiffness. In this paper, a novel Ultralight Hybrid PAM (UH-PAM), based on bellow-type elastomeric skin and vacuum actuation, is presented. In particular, open-cell foam is exploited as a structural backbone, together with plastic rings, all embedded in a thin skin. The design and optimization combine numerical, analytical, and experimental data. Both static and dynamic analysis are performed...

2020 3rd IEEE International Conference on Soft Robotics (RoboSoft), 2020

This paper presents the electromechanical analysis of ultra-light and highly compressible capacit... more This paper presents the electromechanical analysis of ultra-light and highly compressible capacitive pressure sensors based on open-cell foams, with top and bottom surface electrodes built by PEDOT:PSS coating. Multiple samples of porous capacitive sensors were characterized, and experimental results were compared by means of both FEM simulations and theoretical analysis. The agreement between experiments and theoretical/numerical prediction is good, suggesting that this methodology can be a useful tool for fine tuning of the sensor performance (i.e. sensitivity, range) for specific applications. Finally, the proposed foam sensor provides a low-cost, easy-to-implement, robust sensing solution for real-world applications in robotics and wearable systems.

2018 IEEE International Conference on Soft Robotics (RoboSoft), 2018

Soft tactile sensors are core components for enabling soft robots perception. Their performance c... more Soft tactile sensors are core components for enabling soft robots perception. Their performance can be tuned shaping the electromechanical characteristics of their materials and structure at the microscale. In this work, the behavior of soft capacitive pressure sensors, based on porous dielectric material, is studied by means of 2D FEM simulations. In particular, from the mechanical point of view, it is shown how the apparent Young's modulus decreases with increasing porosity. Then, the variation of initial capacitance and the output characteristics with different level of porosity is discussed, showing that the sensitivity in the simulated structure can improve remarkably, with a tenfold increase for porosity around 30%. Deviations from empirical or simplified analytical expression found in the literature are shown and discussed.

2019 2nd IEEE International Conference on Soft Robotics (RoboSoft), 2019

In this paper, we develop and validate a simple processing method suitable for position, pressure... more In this paper, we develop and validate a simple processing method suitable for position, pressure and depth sensing for a simple Soft Optical Waveguide Skin (SOWS). The soft skin consists of an elastomeric sensitive area (69 cm2and 2 mm thick) free of any other material pattern except for infrared emitters and photodetectors embedded at its periphery. When sensing area is touched, the photodetectors experience a loss in light intensity, and if a proper processing algorithm is developed, spatial information can be retrieved. Using adaptive boosting and decision trees as base learners, we develop classification and regression models to map this light intensity variation to our variables of interest: position, pressure and depth of indentation. This simple approach achieves high accuracy in predicting touch position with a spatial resolution of 9 mm, while simultaneously estimating with high precision the pressure level and depth of indentation.

Applied Sciences, 2021

The limits of space travel are continuously evolving, and this creates increasingly extreme chall... more The limits of space travel are continuously evolving, and this creates increasingly extreme challenges for the crew’s health that must be addressed by the scientific community. Long-term exposure to micro-gravity, during orbital flights, contributes to muscle strength degradation and increases bone density loss. In recent years, several exercise devices have been developed to counteract the negative health effects of zero-gravity on astronauts. However, the relatively large size of these devices, the need for a dedicated space and the exercise time-frame for each astronaut, does not make these devices the best choice for future long range exploration missions. This paper presents a quasi-passive exosuit to provide muscle training using a small, portable, proprioceptive device. The exosuit promotes continuous exercise, by resisting the user’s motion, during routine all-day activity. This study assesses the effectiveness of the resistive exosuit by evaluating its effects on muscular e...

International Conference on Space Optics — ICSO 2012, Nov 20, 2017

SCOUT is the acronym of the new facility developed within the XUVLab laboratory of the Department... more SCOUT is the acronym of the new facility developed within the XUVLab laboratory of the Department of Physics and Astronomy of the University of Florence. SCOUT stands for "Small Chamber for Optical UV Tests" and has been designed to perform practical and fast measurements for those experiments requiring an evacuated environment. SCOUT has been thought, designed and manufactured by paying a particular attention to its flexibility and adaptability. The functionality and the capabilities of SCOUT have been recently tested in a measurement campaign to characterize an innovative wire-grid polarizer optimized to work in transmission in the UV band. This paper provides a description of the overall manufactured system and its performance and shows the additional resources available at the XUVLab laboratory in Florence that make SCOUT exploitable by whatever compact (within 1 m) optical experiment that investigates the UV band of the spectrum.

Advanced Engineering Materials, 2019

A sensory textile-based clutch (STBC) activated by vacuum is presented. The STBC is an assembly o... more A sensory textile-based clutch (STBC) activated by vacuum is presented. The STBC is an assembly of two inextensible webbings equipped with 2.3 mm wide rigid bumps fabricated directly on them by a hot embossing technique, and two elastic bands, all air sealed by a silicone elastomer cover. While, in passive mode, the clutch provides low resistance to elongation, upon vacuum, the specular rigid bumps interlock and provide a high withstanding force. The embedded capacitive-based transducer allows encoding the clutch's elongation, with a position resolution reaching 1.15 mm, owing to a real-time processing algorithm. The STBC (140 mm Â 30 mm Â 8 mm) sustains up to 419 N force with an activation pressure of À0.5 atm. The small size of the rigid components and a priming strategy (keeping the pressure at À0.01 atm in disengaged mode) enable response times down to 14 ms for a 115 N blocking force. A preliminary demonstration of a fully worn device shows the potential of the STBC approach for enabling the control of the engagement and disengagement of blocking forces, as well as monitoring of typical parameters of human movement such as knee bending angles, for future developments of light and efficient unpowered exoskeletons.

Micromachines, 2018

Tactile feedback is needed for the interaction of humans with a worn device, and to enable robots... more Tactile feedback is needed for the interaction of humans with a worn device, and to enable robots to gather environmental cues and react to their surroundings [...]

Advanced science (Weinheim, Baden-Wurttemberg, Germany), 2018

In the past few years, soft robotics has rapidly become an emerging research topic, opening new p... more In the past few years, soft robotics has rapidly become an emerging research topic, opening new possibilities for addressing real-world tasks. Perception can enable robots to effectively explore the unknown world, and interact safely with humans and the environment. Among all extero- and proprioception modalities, the detection of mechanical cues is vital, as with living beings. A variety of soft sensing technologies are available today, but there is still a gap to effectively utilize them in soft robots for practical applications. Here, the developments in soft robots with mechanical sensing are summarized to provide a comprehensive understanding of the state of the art in this field. Promising sensing technologies for mechanically perceptive soft robots are described, categorized, and their pros and cons are discussed. Strategies for designing soft sensors and criteria to evaluate their performance are outlined from the perspective of soft robotic applications. Challenges and tren...

Soft Robotics, 2017

Soft robots should move in an unstructured environment and explore it and, to do so, they should ... more Soft robots should move in an unstructured environment and explore it and, to do so, they should be able to measure and distinguish proprioceptive and exteroceptive stimuli. This can be done by embedding mechanosensing systems in the body of the robot. Here, we present a polydimethylsiloxane block sensorized with an electro-optical system and a resistive strain gauge made with the supersonic cluster beam implantation (SCBI) technique. We show how to integrate these sensing elements during the whole fabrication process of the soft body and we demonstrate that their presence does not change the mechanical properties of the bulk material. Exploiting the position of both sensing systems and a proper combination of the output signals, we present a strategy to measure simultaneously external pressure and positive/negative bending of the body. In particular, the optical system can reveal any mechanical stimulation (external from the soft block or due to its own deformation), while the resistive strain gauge is insensitive to the external pressure, but sensitive to the bending of the body. This solution, here applied to a simple block of soft material, could be extended to the whole body of a soft robot. This approach provides detection and discrimination of the two stimuli (pressure and bending), with low computational effort and without significant mechanical constraint.

Detection of human movement requires lightweight, flexible systems to detect mechanical parameter... more Detection of human movement requires lightweight, flexible systems to detect mechanical parameters (like strain and pressure) not interfering with user activity, and that he/she can wear comfortably. In this work we address such multifaceted challenge with the development of smart garments for lower limb motion detection, like a textile kneepad and anklet in which soft sensors and readout electronics are embedded for detecting movement of the specific joint. Stretchable capacitive sensors with a three-electrode configuration are built combining conductive textiles and elastomeric layers, and distributed at knee and ankle. They show an excellent behavior in the ~30% strain range, hence the correlation between their responses and the optically tracked Euler angles is allowed for basic lower limb movements. Bending during knee flexion/extension is detected, and it is discriminated from any external contact by implementing in real time a low computational algorithm. The smart anklet is ...

Frontiers in Materials, 2017

AIP Conference Proceedings, 2009

We propose a layout for a tunable mesoscopic cavity that allows to probe the conductance and nois... more We propose a layout for a tunable mesoscopic cavity that allows to probe the conductance and noise properties of direct transmission channels ("noiseless scattering states"). Our numerical simulations demonstrate how the variation of different gate voltages in the cavity leads to characteristic signatures of such non-universal processes. Using reaUstic assumptions about scattering in two-dimensional heterostructures, our proposed layout should define a viable protocol for an experimental realization.

2009 Proceedings of the European Solid State Device Research Conference, 2009

ABSTRACT The conductance of a tunnel barrier can exhibit a very large enhancement, as a result of... more ABSTRACT The conductance of a tunnel barrier can exhibit a very large enhancement, as a result of constructive interference, if two constrictions are symmetrically placed around the barrier itself, thus defining a cavity. This phenomenon could be exploited for a sensitive detector of electric or magnetic fields, due to the strong dependence of the enhancement effect on symmetry. In order to assess the feasibility of such a sensor, we have studied the robustness of its operation with respect to fabrication tolerances in the lithographic process for the depletion gates used for the definition of the cavity. Here we report results that appear encouraging, since the enhancement effect seems to survive in the presence of localized deformations of the confining depletion gates, while deviations on a larger scale can be compensated modifying the applied gate potentials.

SPIE Proceedings, 2012

ABSTRACT Within the Section of Astronomy of the Department of Physics and Astronomy of the Univer... more ABSTRACT Within the Section of Astronomy of the Department of Physics and Astronomy of the University of Firenze (Italy), the XUVLab laboratory is active since 1998 dedicated to technological development, mainly UV oriented. The technological research is focused both on electronics and optics. Our last approach is dedicated to the development of innovative wiregrid polarizers optimized to work in transmission at 121.6 nm. The manufacturing of such optical devices requires advanced technological expertise and suitable experimental structures. First, nanotechnology capability is necessary, in order to build several tiny parallel conductive lines separated by tens of nanometers on wide areas to be macroscopically exploitable in an optical laboratory. Moreover, the characterization of such an advanced optical device has to be performed in vacuum, being air absorptive at 121.6 nm. A dedicated small vacuum chamber, SCOUT (Small Chamber for Optical UV Tests) was developed within our laboratory in order to perform practical and fast measurements. SCOUT hosts an optical bench and is equipped with several opening flanges, in order to be as flexible as possible. The flexibility that has been reached with SCOUT allows us to use the chamber beyond the goals it was thought for. It is exploitable by whatever compact (within 1 m) optical experiment that investigates the UV band of the spectrum. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).