132 research outputs found
Measuring Triboelectric Energy Conversion in Leaves of Living Plants
No full textContact electrification or triboelectric charging is a long-known ubiquitous phenomenon which occurs on almost all material surfaces. It comprises the generation of longer- or shorter-lived static charges on the surface of a material upon contact with another material. The classical example is the charging of hairs with a rubber balloon. The effect is receiving increased attention as a possible mechanism to convert mechanical energy into electricity for energy harvesting. It is required that an electrode is installed near the charged surface (often a dielectric polymer) into which the generated charges can be electrostatically induced. Multiple artificial energy harvesters have been developed in the last decade to exploit this mechanism. Interestingly, also in nature, configurations exist that allow structures to convert mechanical energy into electricity by the triboelectric effect. These are especially the leaves of all living plants. Indeed, living plants have recently been used as triboelectric energy converters and for harvesting energy from leaf motion in the wind [1]–[5]. Here, we describe in detail how to measure triboelectric charges in the tissue of living plants, the particularities of measuring such signals in the organisms, and what is essential when using them for energy harvesting
Octopus-Inspired Suction Cups with Embedded Strain Sensors for Object Recognition
No full textThe octopus has unique capacities are sources of inspiration in developing soft robotic-enabling technologies. Herein, soft, sensorized, suction cups inspired by the suckers of Octopus vulgaris are presented. The suction cups using direct casting are fabricated, so that materials with different mechanical properties can be combined to optimize sensing and grasping capabilities. The artificial suckers integrate four embedded strain sensors, individually characterized and placed in a 90 degrees configuration along the rim of the suction cup. Based on this arrangement, how well the sensory suction cup can detect 1) the direction and 2) the angle (from 30 degrees to 90 degrees) of a touched inclined surface and 3) the stiffness of a touched flat object (shore hardness between 0010 and D50) both in air and underwater is evaluated. Data processing on neural networks is based using a multilayer perceptron to perform regression on individual properties. The results show a mean absolute error of 0.98 for angles, 0.02 for directions, and 97.9% and 93.5% of accuracy for the material classification in air and underwater, respectively. In view of the results and scalability in manufacturing, the proposed artificial suckers would seem to be highly effective solutions for soft robotics, including blind exploration and object recognition
Plantoid: plant inspired robot for subsoil exploration and environmental monitoring
No full textLa Biorobotica è un nuovo approccio nella realizzazione di robot che unisce diverse discipline come Robotica e Scienze Naturali. Il concetto di Biorobotica è stato identificato per molti anni come ispirazione dal mondo animale. In questa tesi, questo paradigma è stato esteso per la prima volta al mondo vegetale. Le piante sono un organismo affascinante con inaspettate capacità. Sono organismi dinamici e altamente sensibili, in grado di esplorare il terreno alla ricerca di nutrienti e di valutare con precisione la loro situazione per una gestione ottimale delle risorse.
L'obiettivo di questa tesi è di contribuire alla realizzazione di un robot ispirato alle piante, un plantoide. Il robot plantoide comprende sistemi di radici e rami e deve essere in grado di monitorare l'ambiente sia in aria sia nel sottosuolo. Questi robot ispirati alle piante saranno utilizzati per applicazioni specifiche, come il monitoraggio in situ di parametri chimici, la ricerca di acqua in agricoltura, l'ancoraggio e per la comprensione scientifica delle capacità e comportamenti delle piante stesse mediante la costruzione di modelli fisici.
In questa tesi sono stati affrontati diversi aspetti di questa innovativa piattaforma robotica: prima di tutto, lo studio delle piante, le caratteristiche e le tecnologie che consentono di progettare e sviluppare il sistema robotico. Il sistema proposto può essere facilmente suddiviso in due sezioni principali, la parte aerea e la parte radicale (che sta nel sottosuolo).
Per la parte che si trova nel sottosuolo, l'attività è stata incentrata sulla realizzazione di un sistema meccatronico miniaturizzato che imita il comportamento dell’apice radicale della pianta. Le piante mostrano una peculiare direzione crescita in risposta a stimoli esterni, come la luce (phototropism), la gravità (gravitropism), il tatto (thigmotropism) o il gradiente di umidità (hydrotropism). I tropismsi spesso interagiscono tra loro, e la crescita finale della pianta è influenzata da tali interazioni. Al fine di imitare le potenti prestazioni del sistema radicale delle piante, un nuovo attuatore è stato proposto. Questo attuatore è basato sul principio osmotico (attuatore osmotico) e, diversamente dagli attuatori allo stato dell’arte basati sul principio osmotico, è stato progettato in modo da avere una reazione reversibile. Questo attuatore permette di eseguire l'allungamento e il direzionamento dell’ apice radicale, generando elevate forze con un basso consumo di energia (con movimenti nella scala temporale della pianta). Studi teorici su questo attuatore mostrano interessanti prestazioni in termini di pressione di attuazione (superiore a 20 atm), con potenza nell'ordine di alcuni mW e con tempi di attuazione nell’ordine delle ore. L’apice radicale robotico è stato progettato per essere dotato di sensori (gravità e umidità) per imitare le capacità di analisi delle piante, e con l’attuatore osmotico per guidare la crescita nella direzione corretta. Un microcontrollore integrato controlla il comportamento e il direzionamento sulla base delle informazioni provenienti dai sensori.
Riguardo la parte aerea, l'attività in questa tesi è stata incentrata sulla realizzazione di una sorta di modulo di monitoraggio ambientale, al fine di imitare l'elevata capacità sensoristica delle piante. Questa parte è stata progettata e realizzata in un modo più tradizionale, senza tentare di imitare completamente il comportamento delle piante, ma prendendo ispirazione dalle caratteristiche fondamentali (recupero dell’energia, ampia capacità di monitoraggio e comunicazione). Al fine di integrare una vasta quantità di sensori, è stata sviluppata un’innovativa interfaccia che garantisce il condizionamento di sensori, con capacità plug-and-play e basso consumo energetico.
Diversi aspetti del plantoid non sono ancora stati affrontati e saranno parte dei lavori futuri. In particolare, il meccanismo di crescita delle radici (alcune possibili soluzioni sono state proposte e spiegate in questa tesi) e l'integrazione di sensori chimici nell’apice radicale.Biorobotics is a novel approach in the realization of robot that merges different disciplines as Robotic and Natural Science. The concept of biorobotics has been identified for many years as inspiration from the animal world. In this thesis this paradigm has been extended for the first time to the plant world. Plants are an amazing organism with unexpected capabilities. They are dynamic and highly sensitive organisms, actively and competitively foraging for limited resources both above and below ground, and they are also organisms which accurately compute their circumstances, use sophisticated cost–benefit analysis, and take defined actions to mitigate and control diverse environmental insults.
The objective of this thesis is to contribute to the realization of a robot inspired to plants, a plantoid. The plantoid robot includes root and shoot systems and should be able to explore and monitoring the environment both in the air and underground. These plant-inspired robots will be used for specific applications, such as in situ monitoring analysis and chemical detections, water searching in agriculture, anchoring capabilities and for scientific understanding of the plant capabilities/behaviours themselves by building a physical models.
The scientific work performed in this thesis addressed different aspects of this innovative robotic platform development: first of all, the study of the plants‟ characteristics and the enabling technologies in order to design and to develop the overall plantoid system. The proposed system can be easily sub-divided in two major sections, the aerial part and the subsoil part.
About the subsoil part, the activity focused on the realization of a miniaturized mechatronic system that imitates the behaviour of the plant radical apex. Plants show a peculiar directional growth in response to external stimulations, such as light (phototropism), gravity (gravitropism), touch (thigmotropism) or water/humidity gradient (hydrotropism). Tropisms frequently interact between and among each other, and the final grown form of the plant is influenced by such interactions. In order to imitate the powerful performances of the plant root system, a novel actuator has been proposed. This actuator is based on the osmotic principle (osmotic actuator) and, differently by the state-of-the-art actuators based on the osmotic principle, it has been designed in order to have a reversible reaction. This actuator permits to perform the elongation and the typical steering capabilities of the root apex, generating high forces with low power consumption (in the time scale of the plant). Theoretical studies on this actuator show interesting performances in terms of actuation pressure (more than 20 atm) with power in the order of some mW and with actuation in the hours scale time. The robotic root apex was designed to be equipped with sensors (gravity and moisture) to imitate the plants sensing characteristics, and with the novel osmotic actuator to drive the growth in the correct direction. An embedded microcontroller implements the basic root behaviour on the basis of the information coming from the sensors.
About the aerial part the activity in this thesis was focused on the realization of a sort of environmental monitoring module in order to imitate the high sensing capabilities of the plants. This part has been designed and realized in a more traditional way, without attempt to imitate completely the plant behaviour but taking inspiration from the fundamental characteristics (energy scavenging, wide sensing capabilities and communication). In order to integrate a wide amount of sensors an innovative interface board that guarantees the conditioning of the sensor, with plug-and-play capabilities and low power consumption, was developed.
Several aspects of the plantoid system are not faced yet and they will be part of the future works. In particular, the growing mechanism of the roots (some possible solutions are proposed and explained in this thesis) and the integration of chemical sensors in the root apex
Design of Soft Pneumatic Actuator with Two Oblique Chambers for Coupled Bending and Twisting Movements
No full textSoft pneumatic network (Pneu-net) actuators are frequently used to achieve sophisticated movements, but they face challenges in producing both bending and twisting motions concurrently. In this paper, we present a new Pneu-net twisting and bending actuator (PTBA) design that enables them to perform complex motions. We achieved this by adjusting the chamber angle, ranging from 15 to 75 degrees, to optimize the bending and twisting movements through finite element analysis and experimental verification. We also investigated the variation trends in bending and twisting motions and determined the actuator's workspace and maximum grasping force for a variety of objects with different shapes, materials, and sizes. Our findings suggest that PTBA is a promising candidate for advanced applications requiring intricate and bioinspired movements. This new design method offers a path toward achieving these goals
A plant-hybrid system for wind monitoring connected with social media
No full textSoft technologies and soft robotics provide solutions for devices that interact with living organisms without harming them. This also includes the development of Soft systems that can directly interact with plants, with no damage for their tissues, e.g, to detect environmental parameters. Here, we propose a biohybrid wind monitoring system in which the plant itself, together with custom-made soft artificial leaves, establish a self-powered environmental sensor for wind. Based on the system's contact/triboelectrification when vibrating in the wind, electrical signals are generated that correlate with the wind speed and plant motion. The self-powered sensor readout is analyzed and processed to send a Twitter notification on a dedicated account (@SensorPlant) when the wind conditions change. This proof-of-concept study aims as a platform to realize plant-hybrid devices for wind sensing. It is furthermore an example for a soft biohybrid system that records and communicates real-life data autonomously from the plant-level. The system can be customized to many necessities, e.g., it can send a notification when wind increases to the level that could damage the plants in that area. This could have future implications as sustainable, straightforward sensors for agriculture and climate monitoring
Design of a New Real-Time Dosimeter to Monitor Personal Exposure to Elemental Gaseous Mercury
No full textA plant-hybrid system for wind monitoring connected with social media
No full textArticle and Supplementary Video. Please contact the corresponding authors for further information and data.Publication developed within the GrowBot project, funded by the European Union's Horizon 2020 Research and Innovation Programme under Grant Agreement No. 82407
Understanding Preload Force for Grasping Objects with Different Stiffness Using Sensorized Suction Cups
No full textThe ability to grasp objects of varying stiffness is a crucial skill for robotic manipulators to perform tasks in real environments. Sensorized suction cups have been shown to be effective in grasping objects with different stiffness by measuring the preload force applied to the object. In this study, we investigate the effect of preload force on grasping objects with different stiffness using sensorized suction cups. We conducted experiments using sensorized suction cups to measure the preload force applied to objects of varying stiffness. Results show that the preload force depends on the type of material, and it increases with the increase of the stiffness of the object. Those findings provide valuable insights into the design of robotic manipulators that can effectively grasp objects with different stiffness using sensorized suction cups
Living Plant-Hybrid Generators for Multidirectional Wind Energy Conversion
No full textThe largest existing biological interface, the surface of living plants, as it stands is capable of converting mechanical energy into electricity based on a combination of contact electrification and electrostatic induction on the plant surface and its inner tissue. Herein, the first design strategies are reported for living plant-based wind energy harvesting systems that use this effect and that are capable of harvesting simultaneously from multiple leaves of a single plant to upscale the energy output. This is the first study under outdoor-relevant conditions in a controlled test environment that relates plant-based energy conversion to wind speed and wind direction as well as parameters such as the environmental humidity. Increasing the wind speed not only leads to higher power but also low winds of 2 m s(-1) and less can be converted into storable electricity. The plant-hybrid generators are moreover capable of converting wind from multiple directions by exploiting the naturally multiplex leaf orientations and the plants can directly power light-emitting diodes (LEDs) and a digital thermometer. The results draw attention to the opportunity to obtain living plant-hybrid generators, e.g., for applications in constituting environmental sensor networks
Voicing Political Relief through Psalms. Manuel II Palaeologus and the Battle of Ankara
No full textAfter the defeat of Bayezid I against Temūr at Ankara, Manuel II Palaiologos composed a short prose in which Temūr reproaches the captured Sultan, and a psalm. Although the two texts have drawn Barker’s attention, he merely lists some quotes from the Psalter and ends up stating a supposed ineffectiveness of late Byzantine authors in reproducing biblical style.
This approach is inadequate. Together with a handful of contemporary witnesses, Manuel’s works seem to be the most vivid reactions to the unforeseen Turkish defeat and definitely prove the spreading of re-interpretation of the events between 1391 and 1402 through the lents of the Bible. If the reproach against Bayezid can be identified with a specific genre, a composition ἐν εἴδει ψαλμοῦ turns out to be rather uncommon in Byzantine literature. Psalms had been metaphrased for centuries, but the author has decided to accurately reproduce psalmodic style.
But how does a Byzantine author create a psalm? The rhythmical features of the text and its content will be outlined. The psalmodic quotes already listed by Barker will be reconsidered in order to properly understand the tools used by the author. The psalm will be analysed on the basis of the Byzantine rhetorical production, which Manuel proves to know and to handle with skill, and through a comparison with other coeval witnesses.
It is not by chance that an emperor decides to write a psalm on a specific event. Turkish defeat inflamed Constantinopolitans after years of famine, as they felt again protected by the Lord, but many still feared an attack by Temūr. In this historical context, once back to the City, Manuel picked up David’s lyre and praised God as the rightful emperor of the Chosen People
- …
