A Characterization of Actuation Techniques for Generating Movement in Shape-Changing Interfaces

Abstract This article characterizes actuation techniques for generating movement in shape-changing displays with physically reconfigurable geometry. To date, few works in Human Computer Interaction literature provide detailed and reflective descriptions of the implementation techniques used in shape-changing displays. This hinders the rapid development of novel interactions as researchers must initially spend time understanding technologies before prototyping new interactions and applications. To bridge this knowledge gap, we propose a taxonomy that classifies actuator characteristics and simplifies the process for designers to select appropriate technologies that match their requirements for developing shape-displays. We scope our investigation to linear actuators that are used in grid configurations. The taxonomy is validated by (a) examining current implementation techniques of motorized, pneumatic, hydraulic, magnetic, and shape-memory actuators in the literature, (b) constructing prototypes to address limited technical details and explore actuator capabilities in depth, (c) describing a use-case scenario through a case study that details the construction of a 10 ? 10 actuator shape-display, and (d) a set of guidelines to aid researchers in selecting actuation techniques for shape-changing applications. The significance of our taxonomy is twofold. First, we provide an original contribution that enables HCI researchers to appropriately select actuation techniques and build shape-changing applications. This is situated amongst other past works that have investigated broader application scenarios such as a shape-changing vocabulary, a framework for shape transformations, material properties, and technical characteristics of various actuators. Second, we carry out in-depth investigations to validate our taxonomy and expand the knowledge of vertical actuation in shape-changing applications to enable rapid development

3D Printed Deformable Surfaces for Shape-Changing Displays

We use interlinked 3D printed panels to fabricate deformable surfaces that are specifically designed for shape-changing displays. Our exploration of 3D printed deformable surfaces, as a fabrication technique for shape-changing displays, shows new and diverse forms of shape output, visualizations, and interaction capabilities. This article describes our general design and fabrication approach, the impact of varying surface design parameters, and a demonstration of possible application examples. We conclude by discussing current limitations and future directions for this work

Tangible user interfaces : past, present and future directions

In the last two decades, Tangible User Interfaces (TUIs) have emerged as a new interface type that interlinks the digital and physical worlds. Drawing upon users' knowledge and skills of interaction with the real non-digital world, TUIs show a potential to enhance the way in which people interact with and leverage digital information. However, TUI research is still in its infancy and extensive research is required in or- der to fully understand the implications of tangible user interfaces, to develop technologies that further bridge the digital and the physical, and to guide TUI design with empirical knowledge. This paper examines the existing body of work on Tangible User In- terfaces. We start by sketching the history of tangible user interfaces, examining the intellectual origins of this field. We then present TUIs in a broader context, survey application domains, and review frame- works and taxonomies. We also discuss conceptual foundations of TUIs including perspectives from cognitive sciences, phycology, and philoso- phy. Methods and technologies for designing, building, and evaluating TUIs are also addressed. Finally, we discuss the strengths and limita- tions of TUIs and chart directions for future research

Digital Fabrication Approaches for the Design and Development of Shape-Changing Displays

Interactive shape-changing displays enable dynamic representations of data and information through physically reconfigurable geometry. The actuated physical deformations of these displays can be utilised in a wide range of new application areas, such as dynamic landscape and topographical modelling, architectural design, physical telepresence and object manipulation. Traditionally, shape-changing displays have a high development cost in mechanical complexity, technical skills and time/finances required for fabrication. There is still a limited number of robust shape-changing displays that go beyond one-off prototypes. Specifically, there is limited focus on low-cost/accessible design and development approaches involving digital fabrication (e.g. 3D printing). To address this challenge, this thesis presents accessible digital fabrication approaches that support the development of shape-changing displays with a range of application examples – such as physical terrain modelling and interior design artefacts. Both laser cutting and 3D printing methods have been explored to ensure generalisability and accessibility for a range of potential users. The first design-led content generation explorations show that novice users, from the general public, can successfully design and present their own application ideas using the physical animation features of the display. By engaging with domain experts in designing shape-changing content to represent data specific to their work domains the thesis was able to demonstrate the utility of shape-changing displays beyond novel systems and describe practical use-case scenarios and applications through rapid prototyping methods. This thesis then demonstrates new ways of designing and building shape-changing displays that goes beyond current implementation examples available (e.g. pin arrays and continuous surface shape-changing displays). To achieve this, the thesis demonstrates how laser cutting and 3D printing can be utilised to rapidly fabricate deformable surfaces for shape-changing displays with embedded electronics. This thesis is concluded with a discussion of research implications and future direction for this work

Simulation and development of paper-based actuators

Soft robots have become an attractive research topic for opening new doors for robots' limitations by being flexible, light, and small and with the ability to have an adaptable shape. An essential component in a soft robot is the soft actuator, which provides the system with a deformable body and allows it to interact with the environment to achieve the desired actuation pattern. Among the various materials used in soft actuators, paper-based actuators have special attention because paper is an abundant, lightweight, and biodegradable material. This work illustrates an insight into the soft actuators field and focuses on developing unique paper-based actuators applying the microwave heat for a liquid-vapor phase transition, in this case, water. This document focuses on the study of different designs, materials, and thick-nesses by changing the paper, elastomer, and double-sided tape.Os robôs flexíveis tornaram-se um tópico de pesquisa atraente por abrirem novas portas para as limitações dos robôs por serem flexíveis, leves e pequenos e com a capacidade de ter uma forma adaptável. Um componente essencial em um robô flexível é o atuador flexível, que fornece ao sistema um corpo deformável e permite que este interaja com o ambiente para atingir o movi-mento desejado. Dos vários materiais usados em atuadores flexíveis, os atuadores baseados em papel têm especial atenção porque o papel é um material abundante, leve e biodegradável. Este trabalho ilustra uma visão da área de atuadores flexíveis e foca no desenvolvimento de atuadores únicos baseados em papel , aplicando o calor de microondas para uma transição de fase líquido-vapor, neste caso, água. Este documento mostra o estudo de diferentes designs, ma-teriais e espessuras, alterando o papel, elastómero e fita dupla-face

TiNi-based thin films for MEMS applications

In this paper, some critical issues and problems in the development of TiNi thin films were discussed, including preparation and characterization considerations, residual stress and adhesion, frequency improvement, fatigue and stability, as well as functionally graded or composite thin film design. Different types of MEMS applications were reviewed and the prospects for future advances in fabrication process and device development were discussed.Singapore-MIT Alliance (SMA

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

New trends in 4D printing: A critical review

In a variety of industries, Additive Manufacturing has revolutionized the whole design-fabrication cycle. Traditional 3D printing is typically employed to produce static components, which are not able to fulfill the dynamic structures requirements and relevant applications such as soft grippers, self-assembly systems, and smart actuators. To address this limitation, an innovative technology has emerged and is called “4D printing”. It processes smart materials by using 3D printing for fabricating smart structures that can be reconfigured by applying different inputs such as heat, humidity, magnetic, electricity, light etc. At present, 4D printing is still a growing technology and it presents numerous challenges regarding materials, design, simulation, fabrication processes, applied strategies and reversibility. In this work a critical review about 4D printing technologies, materials and applications is discussed