Embodied Intelligence in Soft Robotics Through Hardware Multifunctionality

The soft robotics community is currently wondering what the future of soft robotics is. Therefore, it is very important to identify the directions in which the community should focus its efforts to consolidate its impact. The identification of convincing applications is a priority, especially to demonstrate that some achievements already represent an attractive alternative to current technological approaches in specific scenarios. However, most of the added value of soft robotics has been only theoretically grasped. Embodied Intelligence, being of these theoretical principles, represents an interesting approach to fully exploit soft robotic’s potential, but a pragmatic application of this theory still remains difficult and very limited. A different design approach could be beneficial, i.e., the integration of a certain degree of continuous adaptability in the hardware functionalities of the robot, namely, a “flexible” design enabled by hardware components able to fulfill multiple functionalities. In this paper this concept of flexible design is introduced along with its main technological and theoretical basic elements. The potential of the approach is demonstrated through a biological comparison and the feasibility is supported by practical examples with state-of-the-art technologies

Studio, progettazione e realizzazione di un sistema di attuazione per un robot biomimetico ispirato all'anatomia dell'octopus vulgaris

L’octopus vulgaris ha sempre destato una grande curiosità nel campo della robotica biomimetica. Da un punto di vista ingegneristico, infatti, i suoi tentacoli presentano caratteristiche molto particolari, come la sua elevata capacità di curvatura in tutte le direzioni, la velocità di estensione e la capacità di variare la sua rigidezza. Questa curiosa creatura, nonostante l’apparente semplicità sembra dare molte risposte a robotici impegnati nel campo del controllo e della cinematica, soprattutto riguardo a materiali e sistemi di attuazione per una nuova generazione di robot. Nell’octopus queste capacità motorie sono ottenute grazie alla caratteristiche idrostatica dei suoi muscoli e dalla loro disposizione all’interno del tentacolo. Prendendo ispirazione da questo, è stato avviato un ampio progetto di studio e di analisi sul design e che potrebbe influire sullo sviluppo di nuovi principi di attuazione, sensorizzazione e controllo per robot con prestazioni incrementate in termini di destrezza, controllo e flessibilità. In particolare, è stato disegnato un robot compliante di materiale cedevole, composto da elementi attivi disposti seguendo la scelta compiuta dalla Natura ed in grado di contrarsi così da riprodurre le performance del tentacolo. In questo lavoro di tesi è stato svolto uno studio preliminare sulle caratteristiche passive del materiale biologico, come parte integrante di una caratterizzazione biomeccanica completa dei tessuti del tentacolo. Le prove sono state eseguite su porzioni di tentacolo di octopus vulgaris usando metodi e strumenti ingegneristici quali la misura dell’elasticità attraverso curve di sforzo – deformazione. I dati provenienti da questa indagine sono stati poi utilizzati come riferimento per la scelta dei materiali da utilizzare in quanto in grado di riprodurre il comportamento del tentacolo naturale. Infine sono presentati i modelli ed i tentativi compiuti nella fabbricazione di un sistema di attuazione che, sfruttando i principi dei polimeri elettroattivi (EAP) e la disposizione anatomica naturale, fornisce al tentacolo robotico un range di movimento ed una forza incrementati rispetto ai risultati ottenuti seguendo approcci roboticamente più tradizionali

The Morphological Computation Principles as a New Paradigm for Robotic Design

A theory, by definition, is a generalization of some phenomenon observations, and a principle is a law or a rule that should be followed as a guideline. Their formalization is a creative process, which faces specific and attested steps. The following sections reproduce this logical flow by expressing the principle of Morphological Computation as a timeline: firstly the observations of this phenomenon in Nature has been reported in relation with some recent theories, afterward it has been linked with the current applications in artificial systems and finally the further applications, challenges and objectives will project this principle into future scenarios

A bistable soft gripper with mechanically embedded sensing and actuation for fast closed-loop grasping

Soft robotic grippers are shown to be high effective for grasping unstructured objects with simple sensing and control strategies. However, they are still limited by their speed, sensing capabilities and actuation mechanism. Hence, their usage have been restricted in highly dynamic grasping tasks. This paper presents a soft robotic gripper with tunable bistable properties for sensor-less dynamic grasping. The bistable mechanism allows us to store arbitrarily large strain energy in the soft system which is then released upon contact. The mechanism also provides flexibility on the type of actuation mechanism as the grasping and sensing phase is completely passive. Theoretical background behind the mechanism is presented with finite element analysis to provide insights into design parameters. Finally, we experimentally demonstrate sensor-less dynamic grasping of an unknown object within 0.02 seconds, including the time to sense and actuate

A general method for the design and fabrication of shape memory alloy active spring actuators

Shape memory alloys have been widely proposed as actuators, in fields such as robotics, biomimetics and microsystems: in particular spring actuators are the most widely used, due to their simplicity of fabrication. The aim of this paper is to provide a general model and the techniques for fabricating SMA spring actuators. All the steps of the design process are described: a mechanical model to optimize the mechanical characteristic for a given requirement of force and available space, and a thermal model for the estimation of the electrical power needed for activation. The parameters of both models are obtained by experimental measurements, which are described in the paper. The models are then validated on springs manufactured manually, showing also the fabrication process. The design method is valid for the dimensioning of SMA springs, independently from the external ambient conditions. The influence on the actuator bandwidth was investigated for different working environments, providing numerical indications for the utilization in underwater applications. The spring characteristics can be calculated by the mechanical model with an accuracy of 5%. The thermal model allows one to calculate the current needed for activation under different ambient conditions, in order to guarantee activation in the specific loading conditions. Moreover, two solutions were found to reduce the power consumption by more than 40% without a dramatic reduction of bandwidth

A Self-sensing Inverse Pneumatic Artificial Muscle

In recent years, the inverse pneumatic artificial muscles attained great attention in soft robotics, especially for the wider motion range compared to traditional positive pneumatic actuators. Besides self-sensing is a recognized highly desirable property for soft actuators to enable proprioception and to facilitate the soft robots control, a self-sensing strategy for a soft inverse pneumatic muscle was still missing. In this paper, we present the first self-sensing inverse pneumatic artificial muscle in which the reinforcing but compliant element that guides the actuator motion during actuation has not only a mechanical function but, being also electrically conductive, it endows the actuator with self-sensing. Here, the actuator design and manufacturing are described, together with an electro- mechanical characterization. In addition, we demonstrate its self-sensing capability in a dynamic setting, by predicting the actuator strain from its electric resistance variation, through a calibration model

Actuation Technologies for Soft Robot Grippers and Manipulators: A Review

Purpose of Review The new paradigm of soft robotics has been widely developed in the international robotics community. These robots being soft can be used in applications where delicate yet effective interaction is necessary. Soft grippers and manipulators are important, and their actuation is a fundamental area of study. The main purpose of this work is to provide readers with fast references to actuation technologies for soft robotic grippers in relation to their intended application. Recent Findings The authors have surveyed recent findings on actuation technologies for soft grippers. They presented six major kinds of technologies which are either used independently for actuation or in combination, e.g., pneumatic actuation combined with electro-adhesion, for certain applications. Summary A review on the latest actuation technologies for soft grippers and manipulators is presented. Readers will get a guide on the various methods of technology utilization based on the application

I-support soft arm for assistance tasks: a new manufacturing approach based on 3D printing and characterization

AbstractSoft robotics is an emerging scientific field well known for being widespread employed in several applications where dexterity and safe interaction are of major importance. In particular, a very challenging scenario in which it is involved concerns bio-medical field. In the last few years, several soft robotic devices have been developed to assist elderly people in daily tasks. In this paper, the authors present a new manufacturing approach for the fabrication of I-SUPPORT, a soft arm used to help needful people during shower activities. The proposed I-SUPPORT version, based on pneumatic and cable-driven actuation, is manufactured using Fused Filament Fabrication (FFF), the most common and inexpensive Additive Manufacturing (AM) technology. The advantages offered by FFF technology compared to traditional manufacturing methods regard: (i) the possibility to increase the automation degree of the process by reducing manual tasks, (ii) the decrease of assembly operations and (iii) an improvement in terms of supply chain. Moreover, the constitutive I-SUPPORT elements have been printed separately to save time, reduce materials and optimize the waste in case of failure. Afterwards, the proposed soft robotic arm has been tested to evaluate the performances and of the chambers, module and the whole I-SUPPORT manipulator

Bioinspired Soft Actuation System Using Shape Memory Alloys

Soft robotics requires technologies that are capable of generating forces even though the bodies are composed of very light, flexible and soft elements. A soft actuation mechanism was developed in this work, taking inspiration from the arm of the Octopus vulgaris, specifically from the muscular hydrostat which represents its constitutive muscular structure. On the basis of the authors’ previous works on shape memory alloy (SMA) springs used as soft actuators, a specific arrangement of such SMA springs is presented, which is combined with a flexible braided sleeve featuring a conical shape and a motor-driven cable. This robot arm is able to perform tasks in water such as grasping, multi-bending gestures, shortening and elongation along its longitudinal axis. The whole structure of the arm is described in detail and experimental results on workspace, bending and grasping capabilities and generated forces are presented. Moreover, this paper demonstrates that it is possible to realize a self-contained octopus-like robotic arm with no rigid parts, highly adaptable and suitable to be mounted on underwater vehicles. Its softness allows interaction with all types of objects with very low risks of damage and limited safety issues, while at the same time producing relatively high forces when necessary