The Propulsion of Reconfigurable Modular Robots in Fluidic Environments

Reconfigurable modular robots promise to transform the way robotic systems are designed and operated. Fluidic or microgravity environments, which can be difficult or dangerous for humans to work in, are ideal domains for the use of modular systems. This thesis proposes that combining effective propulsion, large reconfiguration space and high scalability will increase the utility of modular robots. A novel concept for the propulsion of reconfigurable modular robots is developed. Termed Modular Fluidic Propulsion (MFP), this concept describes a system that propels by routing fluid though itself. This allows MFP robots to self-propel quickly and effectively in any configuration, while featuring a cubic lattice structure. A decentralized occlusion-based motion controller for the system is developed. The simplicity of the controller, which requires neither run-time memory nor computation via logic units, combined with the simple binary sensors and actuators of the robot, gives the system a high level of scalabilty. It is proven formally that 2-D MFP robots are able to complete a directed locomotion task under certain assumptions. Simulations in 3-D show that robots composed of 125 modules in a variety of configurations can complete the task. A hardware prototype that floats on the surface of water is developed. Experiments show that robots composed of four modules can complete the task in any configuration. This thesis also investigates the evo-bots, a self-reconfigurable modular system that floats in 2-D on an air table. The evo-bot system uses a stop-start propulsion mechanism to choose between moving randomly or not moving at all. This is demonstrated experimentally for the first time. In addition, the ability of the modules to detect, harvest and share energy, as well as self-assemble into simple structures, is demonstrated

Automated Real-Time Control of Fluidic Self-Assembly of Microparticles

Self-assembly is a key coordination mechanism for large multi-unit systems and a powerful bottom-up technology for micro/nanofabrication. Controlled self-assembly and dynamic reconfiguration of large ensembles of microscopic particles can effectively bridge these domains to build innovative systems. In this perspective, we present SelfSys, a novel platform for the automated control of the fluidic self-assembly of microparticles. SelfSys centers around a water-filled microfluidic chamber whose agitation modes, induced by a coupled ultrasonic actuator, drive the assembly. Microparticle dynamics is imaged, tracked and analyzed in real-time by an integrated software framework, which in turn algorithmically controls the agitation modes of the microchamber. The closed control loop is fully automated and can direct the stochastic assembly of microparticle clusters of preset dimension. Control issues specific to SelfSys implementation are discussed, and its potential applications presented. The SelfSys platform embodies at microscale the automated self-assembly control paradigm we first demonstrated in an earlier platform

Kinetic Blocks: Actuated Constructive Assembly for Interaction and Display

Pin-based shape displays not only give physical form to digital information, they have the inherent ability to accurately move and manipulate objects placed on top of them. In this paper we focus on such object manipulation: we present ideas and techniques that use the underlying shape change to give kinetic ability to otherwise inanimate objects. First, we describe the shape display's ability to assemble, disassemble, and reassemble structures from simple passive building blocks through stacking, scaffolding, and catapulting. A technical evaluation demonstrates the reliability of the presented techniques. Second, we introduce special kinematic blocks that are actuated and sensed through the underlying pins. These blocks translate vertical pin movements into other degrees of freedom like rotation or horizontal movement. This interplay of the shape display with objects on its surface allows us to render otherwise inaccessible forms, like overhangs, and enables richer input and output

Responsive Megastructures:Growing Future Cities for Global Challenges

From the mid-twentieth century the primary drivers for cities were industrialization and globalization, as urban development sought to maximize productivity and access to labour and resources along with connectivity to markets. More recently, these drivers have been augmented and, in some contexts, replaced by those that emphasize people and their environment over profit. As the manifold anthropogenic impacts of cities present increasingly urgent and major global challenges, it is clear we need a new vision for collective life. This paper therefore examines the development of fast-paced future cities throughout history and, in particular, the dominant technological thrust that characterizes them. As we move further into the twenty-first century, the emergence of new socially engaged visions for future cities that are coupled with environmental concerns suggest a positive shift away from those futures driven primarily technological expectation. We then explore these alternatives by identifying those visions which suggest social futures and global futures. Despite their initial promise, our research has detected an ongoing convergence of visions for future cities rather than radical alternatives. In an era of rapid transformation and global uncertainties it is evident we need to forge new pathways for the design and delivery of habitats for collective life. We conclude our paper by presenting a prototype of a responsive megastructure. Conceived as a ‘living material eco-system’, this responsive megastructure anticipates and is receptive to fluctuating demands by sharing resources (e.g. material, energy, spatial, financial). We explain how matter can be programmed through ‘tuneable environments’ so various shapes, patterns and structures can be grown. In doing so, we present a new vision for megastructures, where matter can be aggregated and scaled to grow future cities, that can embody the complexities of urban life in heterogeneous contexts around the world and respond to their situation and future challenges

Workshop on "Robotic assembly of 3D MEMS".

Proceedings of a workshop proposed in IEEE IROS'2007.The increase of MEMS' functionalities often requires the integration of various technologies used for mechanical, optical and electronic subsystems in order to achieve a unique system. These different technologies have usually process incompatibilities and the whole microsystem can not be obtained monolithically and then requires microassembly steps. Microassembly of MEMS based on micrometric components is one of the most promising approaches to achieve high-performance MEMS. Moreover, microassembly also permits to develop suitable MEMS packaging as well as 3D components although microfabrication technologies are usually able to create 2D and "2.5D" components. The study of microassembly methods is consequently a high stake for MEMS technologies growth. Two approaches are currently developped for microassembly: self-assembly and robotic microassembly. In the first one, the assembly is highly parallel but the efficiency and the flexibility still stay low. The robotic approach has the potential to reach precise and reliable assembly with high flexibility. The proposed workshop focuses on this second approach and will take a bearing of the corresponding microrobotic issues. Beyond the microfabrication technologies, performing MEMS microassembly requires, micromanipulation strategies, microworld dynamics and attachment technologies. The design and the fabrication of the microrobot end-effectors as well as the assembled micro-parts require the use of microfabrication technologies. Moreover new micromanipulation strategies are necessary to handle and position micro-parts with sufficiently high accuracy during assembly. The dynamic behaviour of micrometric objects has also to be studied and controlled. Finally, after positioning the micro-part, attachment technologies are necessary

3D Assembly For Programmable Matter And Hollow Fiber Membrane Gas Exchange In Planar Photobioreactors

In my Ph.D. research I have applied mechanical engineering knowledge and approaches to develop technologies for two topics: programmable matter and green energy through biofuels. Specifically, I have addressed the issues of 3D assembly in a fluid environment and gas exchange in photobioreactors. In the first part of this dissertation, I investigated a programmable matter system that consists of cm-scale building blocks which are agitated in a stochastic flow pattern and assembled using local fluid forces. The fundamental aspect of this approach that my research concentrated on was the problem of component alignment. Towards this end we developed a novel alignment strategy and characterized it using a combination of numerical simulations and experiments. In the second part of this dissertation, I demonstrate the optimal geometric and operational conditions for CO2 transport to planar cultures of photosynthetic organisms via hollow fiber membranes. Firstly, I examined the growth pattern of Synechococcus elongatus around individual hollow fiber membranes to determine the optimal spacing and conditions for maximizing photosynthetic activity. I expanded on this initial work and used the information from the single fiber experiments to design, fabricate, and characterize arrays of HFM fibers. By using this novel configuration of hollow fiber membranes, I was able to grow and sustain an organism culture with effectiveness comparable to state of the art methods while eliminating the need for media circulation and replenishment and allowing for integration into waveguide photobioreactors

Design of a pneumatic soft robotic actuator using model-based optimization

In this thesis, the design and optimization process of a novel soft intelligent modular pad (IntelliPad) for the purpose of pressure injury prevention is presented. The structure of the IntelliPad consists of multiple individual multi-chamber soft pneumatic-driven actuators that use pressurized air and vacuum. Each actuator is able to provide both vertical and horizontal motions that can be controlled independently. An analytical modeling approach using multiple cantilever beams and virtual springs connected in a closed formed structure was developed to analyze the mechanical performance of the actuator. The analytical approach was validated by a finite element analysis. For optimizing the actuator\u27s mechanical performance, firefly algorithm and deep reinforcement learning-based design optimization frameworks were developed with the purpose of maximizing the horizontal motion of the top surface of the actuators, while minimizing its corresponding effect on the vertical motion. Four optimized designs were fabricated. The actuators were tested and validated experimentally to demonstrate their required mechanical performance in order to regulate normal and shear stresses at the skin-pad interface for pressure injury prevention applications

Shape formation by self-disassembly in programmable matter systems

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 225-236).Programmable matter systems are composed of small, intelligent modules able to form a variety of macroscale objects with specific material properties in response to external commands or stimuli. While many programmable matter systems have been proposed in fiction, (Barbapapa, Changelings from Star Trek, the Terminator, and Transformers), and academia, a lack of suitable hardware and accompanying algorithms prevents their full realization. With this thesis research, we aim to create a system of miniature modules that can form arbitrary structures on demand. We develop autonomous 12mm cubic modules capable of bonding to, and communicating with, four of their immediate neighbors. These modules are among the smallest autonomous modular robots capable of sensing, communication, computation, and actuation. The modules employ unique electropermanent magnet connectors. The four connectors in each module enable the modules to communicate and share power with their nearest neighbors. These solid-state connectors are strong enough for a single inter-module connection to support the weight of 80 other modules. The connectors only consume power when switching on or off; they have no static power consumption. We implement a number of low-level communication and control algorithms which manage information transfer between neighboring modules. These algorithms ensure that messages are delivered reliably despite challenging conditions. They monitor the state of all communication links and are able to reroute messages around broken communication links to ensure that they reach their intended destinations. In order to accomplish our long-standing goal of programmatic shape formation, we also develop a suite of provably-correct distributed algorithms that allow complex shape formation. The distributed duplication algorithm that we present allows the system to duplicate any passive object that is submerged in a collection of programmable matter modules. The algorithm runs on the processors inside the modules and requires no external intervention. It requires 0(1) storage and O(n) inter-module messages per module, where n is the number of modules in the system. The algorithm can both magnify and produce multiple copies of the submerged object. A programmable matter system is a large network of autonomous processors, so these algorithms have applicability in a variety of routing, sensor network, and distributed computing applications. While our hardware system provides a 50-module test-bed for the algorithms, we show, by using a unique simulator, that the algorithms are capable of operating in much larger environments. Finally, we perform hundreds of experiments using both the simulator and hardware to show how the algorithms and hardware operate in practice.by Kyle William Gilpin.Ph.D

Movement of Modular Hydraulic Propulsion robots: Decentralised and reactive pose control strategies

Modular robotic systems consist of a set of reconfigurable units, called modules, which can be combined in a multitude of ways to produce robots of different shaps . One of the challenges in the design of these system is to enable them to perform precise movements in their environment. Control strategies that are centralised or rely on external sensing can limit the robustness and scalability of the system. This thesis focuses on the development of control strategies that allow the position and orientation (pose) of a modular robot to be controlled in a fully decentralised and reactive manner. The strategies are designed for the Modular Hydraulic Propulsion (MHP) system, wich operates in a liquid environment. An MHP robot is made of cubic modules, which create a fluid network when connected together. To move, the robot routes through this network fluid from the environment. A physical implementation of the MHP concept is designed, built and validated. An MHP robot’s ability to translate efficiently towards a goal is tested using occlusion based controllers, both with and without communication between modules. The robot is shown to reach the goal using either of the controllers. When using communication, an average of 70% of energy is saved, at the cost of a longer completion time. This thesis proposes multiple minimalistic controllers to control the pose of MHP robots. The robot is required to reach a goal in a preferred orientation. All of the controllers use binary sensing and actuation, with each module using only two bits of sensory information per face. The controllers are proposed for robots moving in 2D and 3D space, and use up to five bits of communication between modules. We prove that robots of convex shape are guaranteed to complete the task. Using computer simulations, the controllers are tested in different environments, using multiple module sizes and under the effect of noise. Additionally, their performance is compared against a centralised controller from the literature. Given the simplicity of the solutions, modules could potentially be realised at scales below a millimetre-cube, where robots of high spatial resolution could perform accurate movements in liquid environments

'Parametric Matter':Pushing’ Updates into Materials and theImplications of Legacy and Lag

This paper discusses an ongoing interdisciplinary research project that develops a design and fabrication approach termed; tunable environments. This is an explorative approach, which enables updates from a digital parametric interface to be ‘pushed' into a 2D, 18x18 cm material sample, by modulating stimuli, so multi properties can be updated/tuned at high resolutions. Our prototype explores how iterative updates can be achieved, which can be temporarily frozen in time. This opens up the idea of creating Parametric Matter/circular materials, which could reduce waste that can be attributed to typical linear processes. Additionally, highly bespoke, ‘time-based’ structures could be achieved. However new implications for design and fabrication arise based on: time-lag of materials, a legacy of interactions, resetting materials as well as challenges of determining associations and desirable material properties