A Soft Robot for Random Exploration of Terrestrial Environments

A swarm of randomly moving miniature robots is an effective solution for the exploration of unknown terrains. However, the deployment of a swarm of miniature robots poses two challenges: finding an adequate locomotion strategy for fast exploration and obstacles negotiation; and implementing simple design and control solutions suited for mass manufacturing. Here, we tackle these challenges by developing a new soft robot with a minimalistic design and a simple control strategy that can randomly propel itself above obstacles and roll on the ground upon landing. The robot is equipped with two propellers that are periodically activated to jump, a soft cage that protects the robot from impacts and allows to passively roll on the ground, and a passive self-righting mechanism for repetitive jumps. The minimalistic control and design reduce the complexity of the mechanics and electronics and are instrumental to the production of a large number of robots. In the paper, the key design aspects of the robot are discussed, the locomotion of a single prototype is experimentally characterized, and improvements of the system for future swarm operations are discussed

Soft Robotics: Design for Simplicity, Performance, and Robustness of Robots for Interaction with Humans.

This thesis deals with the design possibilities concerning the next generation of advanced Robots. Aim of the work is to study, analyse and realise artificial systems that are essentially simple, performing and robust and can live and coexist with humans. The main design guideline followed in doing so is the Soft Robotics Approach, that implies the design of systems with intrinsic mechanical compliance in their architecture. The first part of the thesis addresses design of new soft robotics actuators, or robotic muscles. At the beginning are provided information about what a robotic muscle is and what is needed to realise it. A possible classification of these systems is analysed and some criteria useful for their comparison are explained. After, a set of functional specifications and parameters is identified and defined, to characterise a specific subset of this kind of actuators, called Variable Stiffness Actuators. The selected parameters converge in a data-sheet that easily defines performance and abilities of the robotic system. A complete strategy for the design and realisation of this kind of system is provided, which takes into account their me- chanical morphology and architecture. As consequence of this, some new actuators are developed, validated and employed in the execution of complex experimental tasks. In particular the actuator VSA-Cube and its add-on, a Variable Damper, are developed as the main com- ponents of a robotics low-cost platform, called VSA-CubeBot, that v can be used as an exploratory platform for multi degrees of freedom experiments. Experimental validations and mathematical models of the system employed in multi degrees of freedom tasks (bimanual as- sembly and drawing on an uneven surface), are reported. The second part of the thesis is about the design of multi fingered hands for robots. In this part of the work the Pisa-IIT SoftHand is introduced. It is a novel robot hand prototype designed with the purpose of being as easily usable, robust and simple as an industrial gripper, while exhibiting a level of grasping versatility and an aspect comparable to that of the human hand. In the thesis the main theo- retical tool used to enable such simplification, i.e. the neuroscience– based notion of soft synergies, are briefly reviewed. The approach proposed rests on ideas coming from underactuated hand design. A synthesis method to realize a desired set of soft synergies through the principled design of adaptive underactuated mechanisms, which is called the method of adaptive synergies, is discussed. This ap- proach leads to the design of hands accommodating in principle an arbitrary number of soft synergies, as demonstrated in grasping and manipulation simulations and experiments with a prototype. As a particular instance of application of the method of adaptive syner- gies, the Pisa–IIT SoftHand is then described in detail. The design and implementation of the prototype hand are shown and its effec- tiveness demonstrated through grasping experiments. Finally, control of the Pisa/IIT Hand is considered. Few different control strategies are adopted, including an experimental setup with the use of surface Electromyographic signals

Design and analysis of active fluid-and-cellular solid composites for controllable stiffness robotic elements

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (leaves 107-108).The purpose of this thesis is to investigate the use of a new class of materials for realizing soft robots. Specifically, meso-scale composites--composed of cellular solids impregnated with active fluids-were be designed to have controllable stiffness to take the form of a continuous body of a soft robot. This represents an improvement compared to past efforts in soft robotics, which often involved modifying the infrastructure of current, rigid robots to yield softer ones. This latter approach often faced the challenges of developing actuators that were "soft" but still discrete, and were limited in performance. In contrast, the controllable-stiffness composites proposed in this thesis eliminate the need for multiple actuators; a single structure can transition between various states to serve as both rigid, load-bearing components as well as morphable, compliant ones. While the vast range of fluid-foam combinations for such an application have yet to be explored, the work presented here focuses on a specific composite: open-cell polyurethane foam impregnated with wax. This type of composite can be thermally activated to exhibit both solid and nearly fluid states (while the wax can be melted to become a fluid, the foam holds the composite together as a pseudo-solid). This thesis discusses the research that has been conducted to 1) characterize the mechanical properties of wax-foam composites as well as 2) investigate possible ways in which the composites can be used as robotic components.by Nadia G. Cheng.S.M

Multiscale methods for fabrication design

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 135-146).Modern manufacturing technologies such as 3D printing enable the fabrication of objects with extraordinary complexity. Arranging materials to form functional structures can achieve a much wider range of physical properties than in the constituent materials. Many applications have been demonstrated in the fields of mechanics, acoustics, optics, and electromagnetics. Unfortunately, it is difficult to design objects manually in the large combinatorial space of possible designs. Computational design algorithms have been developed to automatically design objects with specified physical properties. However, many types of physical properties are still very challenging to optimize because predictive and efficient simulations are not available for problems such as high-resolution non-linear elasticity or dynamics with friction and impact. For simpler problems such as linear elasticity, where accurate simulation is available, the simulation resolution handled by desktop workstations is still orders of magnitudes below available printing resolutions. We propose to speed up simulation and inverse design process of fabricable objects by using multiscale methods. Our method computes coarse-scale simulation meshes with data-drive material models. It improves the simulation efficiency while preserving the characteristic deformation and motion of elastic objects. The first step in our method is to construct a library of microstructures with their material properties such as Young's modulus and Poisson's ratio. The range of achievable material properties is called the material property gamut. We developed efficient sampling method to compute the gamut by focusing on finding samples near and outside the currently sampled gamut. Next, with a pre-computed gamut, functional objects can be simulated and designed using microstructures instead of the base materials. This allows us to simulate and optimize complex objects at a much coarser scale to improve simulation efficiency. The speed improvement leads to designs with as many as a trillion voxels to match printer resolutions. It also enables computational design of dynamic properties that can be faithfully reproduced in reality. In addition to efficient design optimization, the gamut representation of the microstructure envelope provides a way to discover templates of microstructures with extremal physical properties. In contrast to work where such templates are constructed by hand, our work enables the first computational method to automatically discovery microstructure templates that arise from voxel representations.by Desai Chen.Ph. D

POLYMERIC IMPULSIVE ACTUATION MECHANISMS: DEVELOPMENT, CHARACTERIZATION, AND MODELING

Recent advances in the field of biomedical and life-sciences are increasingly demanding more life-like actuation with higher degrees of freedom in motion at small scales. Many researchers have developed various solutions to satisfy these emerging requirements. In many cases, new solutions are made possible with the development of novel polymeric actuators. Advances in polymeric actuation not only addressed problems concerning low degree of freedom in motion, large system size, and bio-incompatibility associated with conventional actuators, but also led to the discovery of novel applications, which were previously unattainable with conventional engineered systems. This dissertation focuses on developing novel actuation mechanisms for soft polymeric gel systems with easily adjustable mechanochemical properties and applicability to various environmental conditions. Inspired by stunning examples in nature which exhibit extremely fast motion in a repeatable manner, termed impulsive motion, we have developed polymeric gel actuators applicable for small-scale, self-contained impulsive systems. In particular, we focused on the effect of geometry and the mechanics of surface-mediated stresses on the dynamic shape-change of polymer gel actuators. We found new opportunities from observation of transient deformations which occur during swelling, or deswelling, of asymmetric gels. We described the development of time-dependent three-dimensional deformation mechanism (4D fabrication) by the utilization of transient inhomogeneous swelling state of the asymmetric polymer gel. We discussed the mechanism and the application of the new deformations mechanism for the development of a novel functionality: chemical gradient sensor. In addition, we developed a high-rate and large-strain reversible actuation mechanism for sub-micrometer scale polymeric gel actuators by utilizing balanced effects of two surface-mediated phenomena, surface diffusion and interfacial-tension, and elasticity of soft and small-scale hydrogels. These new findings were harnessed for developing autonomously controlled power amplified polymeric gel devices. Utilizing deswelling induced transient deformation of gel, we developed design principles for generating meta-stable structures and inducing self-regulating transition forces for repeated snap-through buckling transition of polymeric gel devices. In parallel, we deconvoluted the effect of material properties and geometry on dynamic deformations by establishing simulation models and conducting analyses on the performances of actual synthetic systems. The systematic approach will serve to broaden the application spectrum and manufacturing possibilities of polymeric actuator systems

Legged Robots for Object Manipulation: A Review

Legged robots can have a unique role in manipulating objects in dynamic, human-centric, or otherwise inaccessible environments. Although most legged robotics research to date typically focuses on traversing these challenging environments, many legged platform demonstrations have also included "moving an object" as a way of doing tangible work. Legged robots can be designed to manipulate a particular type of object (e.g., a cardboard box, a soccer ball, or a larger piece of furniture), by themselves or collaboratively. The objective of this review is to collect and learn from these examples, to both organize the work done so far in the community and highlight interesting open avenues for future work. This review categorizes existing works into four main manipulation methods: object interactions without grasping, manipulation with walking legs, dedicated non-locomotive arms, and legged teams. Each method has different design and autonomy features, which are illustrated by available examples in the literature. Based on a few simplifying assumptions, we further provide quantitative comparisons for the range of possible relative sizes of the manipulated object with respect to the robot. Taken together, these examples suggest new directions for research in legged robot manipulation, such as multifunctional limbs, terrain modeling, or learning-based control, to support a number of new deployments in challenging indoor/outdoor scenarios in warehouses/construction sites, preserved natural areas, and especially for home robotics.Comment: Preprint of the paper submitted to Frontiers in Mechanical Engineerin

Multiparametric interfaces for fine-grained control of digital music

Digital technology provides a very powerful medium for musical creativity, and the way in which we interface and interact with computers has a huge bearing on our ability to realise our artistic aims. The standard input devices available for the control of digital music tools tend to afford a low quality of embodied control; they fail to realise our innate expressiveness and dexterity of motion. This thesis looks at ways of capturing more detailed and subtle motion for the control of computer music tools; it examines how this motion can be used to control music software, and evaluates musicians’ experience of using these systems. Two new musical controllers were created, based on a multiparametric paradigm where multiple, continuous, concurrent motion data streams are mapped to the control of musical parameters. The first controller, Phalanger, is a markerless video tracking system that enables the use of hand and finger motion for musical control. EchoFoam, the second system, is a malleable controller, operated through the manipulation of conductive foam. Both systems use machine learning techniques at the core of their functionality. These controllers are front ends to RECZ, a high-level mapping tool for multiparametric data streams. The development of these systems and the evaluation of musicians’ experience of their use constructs a detailed picture of multiparametric musical control. This work contributes to the developing intersection between the fields of computer music and human-computer interaction. The principal contributions are the two new musical controllers, and a set of guidelines for the design and use of multiparametric interfaces for the control of digital music. This work also acts as a case study of the application of HCI user experience evaluation methodology to musical interfaces. The results highlight important themes concerning multiparametric musical control. These include the use of metaphor and imagery, choreography and language creation, individual differences and uncontrol. They highlight how this style of interface can fit into the creative process, and advocate a pluralistic approach to the control of digital music tools where different input devices fit different creative scenarios