Toward a Variable Stiffness Surgical Manipulator Based on Fiber Jamming Transition

Soft robots have proved to represent a new frontier for the development of intelligent machines able to show new capabilities that can complement those currently performed by robots based on rigid materials. One of the main application areas where this shift is promising an impact is minimally invasive surgery. In previous works, the STFF-FLOP soft manipulator has been introduced as a new concept of using soft materials to develop endoscopic tools. In this paper, we present a novel kind of stiffening system based on fiber jamming transition that can be embedded in the manipulator to widen its applicability by increasing its stability and with the possibility to produce and transmit higher forces. The STIFF-FLOP original module has been re-designed in two new versions to incorporate the variable stiffness mechanism. The two designs have been evaluated in terms of dexterity and variable stiffness capability and, despite a general optimization rule did not clearly emerge, the study confirmed that fiber jamming transition can be considered an effective technological approach for obtaining variable stiffness in slender soft structures

Contest-Driven Soft-Robotics Boost: The RoboSoft Grand Challenge

This paper reports the design process, the implementation and the results of a novel robotic contest addressing soft robots, named RoboSoft Grand Challenge. Application-oriented tasks were proposed in three different scenarios where soft robotics is particularly lively: manipulation, terrestrial and underwater locomotion. Starting from about sixty expressions of interest submitted by international teams distributed across the world, nineteen robots were eventually selected to participate in the challenge in two of the initially proposed scenarios, i.e. manipulation and terrestrial locomotion. Results highlight both the effectiveness and limitations of state of the art soft robots with respect to the selected tasks. The paper will also focus on some of the advantages and disadvantages of contests as technology-steering mechanisms, including what we called "reductionist design", a phenomenon in which simplistic solutions are devised to purposely tackle the proposed tasks, possibly hindering more general and desired technological advancements

Transcriptional modulations induced by proton irradiation in mice skin in function of adsorbed dose and distance

Hadron therapy by proton beams represents an advanced anti-cancer strategy due to its highly localized dose deposition allowing a greater sparing of normal tissue and/or organs at risk compared to photon/electron radiotherapy. However, it is not clear to what extent non-targeted effects such as transcriptional modulations produced along the beamline may diffuse and impact the surrounding tissue. In this work, we analyze the transcriptome of proton-irradiated mouse skin and choose two biomarker genes to trace their modulation at different distances from the beam's target and at different doses and times from irradiation to understand to what extent and how far it may propagate, using RNA-Seq and quantitative RT-PCR. In parallel, assessment of lipids alteration is performed by FTIR spectroscopy as a measure of tissue damage. Despite the observed high individual variability of expression, we can show evidence of transcriptional modulation of two biomarker genes at considerable distance from the beam's target where a simulation system predicts a significantly lower adsorbed dose. The results are compatible with a model involving diffusion of transcripts or regulatory molecules from high dose irradiated cells to distant tissue's portions adsorbing a much lower fraction of radiation

Modello teorico e sperimentale della laringe come simulatore del funzionamento fisiologico

Il seguente lavoro di tesi sviluppato presso l’Istituto di BioRobotica, Polo Sant’Anna Valdera, sotto la supervisione della Prof.ssa Cecilia Laschi e dell’Ing. Matteo Cianchetti, in collaborazione con l’U.O. Otorinolaringoiatria Audiologia Foniatria Universitaria dell’Azienda Ospedaliero-Universitaria Pisana coordinata dal Prof. Bruno Fattori affronta la problematica relativa alla realizzazione di una piattaforma robotica in grado di riprodurre le principali strutture della laringe, con particolare attenzione alle corde vocali da affiancare alle tradizionali tecniche, sempre più sofisticate, presenti in ambito semiologico, per una più facile interpretazione dei vari eventi fisiopatologici. Ci si propone di sviluppare un modello fisico di corde vocali in cui le priorità diventano sintesi funzionale, e il controllo diretto sulle fisicità del problema quali forma, dimensioni, posizione e caratteristiche meccaniche del tessuto. Solitamente l’approccio alla modellazione della sorgente glottale si divide in due grandi domini: modellazione a parametri concentrati cui fanno capo i modelli biomeccanici (massa-molla-smorzatore) e quella a parametri distribuiti come i modelli ad elementi finiti. L’implementazione di un modello biomimetico della laringe che rispecchia la controparte naturale non solo costituisce un’innovazione nel campo della medicina ma dovrebbe, allo stesso tempo, portare con sé ad un avanzamento delle tecnologie robotiche nell’ambito della “Soft Robotics” in termini di materiali ed attuatori

Stiffening in soft robotics: A review of the state of the art

The need for building robots with soft materials emerged recently from considerations of the limitations of service robots in negotiating natural environments, from observation of the role of compliance in animals and plants [1], and even from the role attributed to the physical body in movement control and intelligence, in the so-called embodied intelligence or morphological computation paradigm [2]-[4]. The wide spread of soft robotics relies on numerous investigations of diverse materials and technologies for actuation and sensing, and on research of control techniques, all of which can serve the purpose of building robots with high deformability and compliance. But the core challenge of soft robotics research is, in fact, the variability and controllability of such deformability and compliance

Soft Robotics

This chapter is organized into two main parts: the first one focuses on different applications of the casting technique for developing different soft robots; the second one is an overview of the manufacturing procedures employed in soft robotics. We don’t have the ambition to cover the entire state of the art, but we aim to provide readers with guidelines to steer their research. Soft robots can be grouped into classes, according to their capabilities, as follows: locomotion, manipulation, and robots mimicking body parts (simulators). For each of these classes, we have identified key examples as means for describing the employed manufacturing procedure: (i) Locomotion—FASTT based on fiber-reinforced actuators; (ii) Manipulation—Octopus, STIFF-FLOP, Gripper that exploits different actuation strategies: cables, fluidic actuation combined with granular jamming and cable-driven under-actuation mechanism, respectively; (iii) Body parts simulator—Simulator of vocal folds that rely on the intrinsic mechanical properties of soft materials. The common denominator among these three classes is the design and prototyping of molds that replicate the shape of the robot. Molds could be made by common machinery (or also by traditional 3D printers) and were used as means for shaping the soft body

Preliminary experimental study on variable stiffness structures based on fiber jamming for soft robots

Soft robotics opened a new set of technological challenges in using soft materials to build robots. The ability of change stiffness is among the most important, because it enables the possibility to tune forces exchanged with the environment. Granular and layer jamming transition have already demonstrated to be a promising approach for developing variable stiffness structures, but no studies have been dedicated to specifically fiber jamming so far. In this paper, we report a preliminary comparative study on fiber jamming applied to cylindrical structures. Fibers of different materials have been used as filler and tested under bending conditions. The results show that up to 380% of stiffness increase can be achieved, in line with data collected on similar devices that use granular jamming. The role of the main mechanical and geometrical parameters have been discussed: Elastic properties are fundamental, but optimal performance can be achieved only with ordered arrangements of the fibers; geometrical features seem secondary, but surface roughness has an important role in preventing sliding. This is a preliminary study, but it already defines a first set of guidelines that can help and promote future works on the development and integration of the fiber jamming in soft systems

Fiber Jamming Transition as a Stiffening Mechanism for Soft Robotics

Robots made of soft materials are demonstrating to be well suited in applications where dexterity and intrinsic safety are necessary. However, one of the most challenging goals of soft robotics remains the ability to change the stiffness of body parts to guarantee stability and to produce significant forces. Among soft actuation technologies reported in literature, the jamming phenomenon is now achieving resounding interest. The jamming transition was observed and studied both with granular and laminar material; however, there is a third possibility that is not gaining the attention that probably would deserve: the fiber jamming. The aim of this study was an attempt to analyze the main parameters influencing the fiber jamming transition as promising stiffening solution for soft robotics. A preliminary analysis to choose the most suitable filling material and the external membrane that compose the system was performed and three possible configurations were designed. The prototypes thus assembled were experimentally investigated by using two different setups: one for conducting comparative bending tests on the systems and another for assessing the mechanical properties of single filling fibers. The results of the tests are used to feature the correlation between the arrangement and the material properties of the fibers and the stiffening capability of the fiber jamming systems. The investigation has shown performances comparable with those obtained with granular and layer jamming, demonstrating that fiber jamming is a good candidate for integration in soft robotic devices

A biorobotic model of the human larynx

This work focuses on a physical model of the human larynx that replicates its main components and functions. The prototype reproduces the multilayer vocal folds and the ab/adduction movements. In particular, the vocal folds prototype is made with soft materials whose mechanical properties have been obtained to be similar to the natural tissue in terms of viscoelasticity. A computational model was used to study fluid-structure interaction between vocal folds and the airflow. This tool allowed us to make a comparison between theoretical and experimental results. Measurements were performed with this prototype in an experimental platform comprising a controlled air flow, pressure sensors and a high-speed camera for measuring vocal fold vibrations. Data included oscillation frequency at the onset pressure and glottal width. Results show that the combination between vocal fold geometry, mechanical properties and dimensions exhibits an oscillation frequency close to that of the human vocal fold. Moreover, computational results show a high correlation with the experimental one