Freeform Fabrication of Electroactive Polymer Actuators and Electromechanical Devices

In pursuit of the goal of producing complete electromechanical systems entirely via solid freeform fabrication, we are developing a library of mutually compatible, functional, freeform elements. Several essential elements – actuation, sensing, and control electronics - still remain to be incorporated into this library. Conducting polymers (CP) are a class of materials which can be used to produce all of these functionalities. Meanwhile, research into actuatable “smart” materials has produced other candidate materials for freeform fabricated actuators that are compatible with our library. We have succeeded in manually producing air-operable actuators that have processing and operating requirements that are compatible with our power source and mechanical component library elements. A survey of candidate actuator materials is presented, experiments performed with two types of actuator materials are described, and complete SFF-producible actuator devices are demonstrated.Mechanical Engineerin

Freeform Fabrication of Ionomeric Polymer-Metal Composite Actuators

Ionomeric polymer-metal composite (IPMC) actuators are a type of soft electromechanically active material which offers large displacement, rapid motion with only ~1V stimulus. IPMC’s are entering commercial applications in toys (Ashley 2003) and biomedical devices (Soltanpour 2001; Shahinpoor 2002; Shahinpoor, Shahinpoor et al. 2003; Soltanpour and Shahinpoor 2003; Soltanpour and Shahinpoor 2004), but unfortunately they can only actuate by bending, limiting their utility. Freeform fabrication offers a possible means of producing IPMC with novel geometry and/or tightly integrated with mechanisms which can yield linear or more complex motion. We have developed materials and processes which allow us to freeform fabricate complete IPMC actuators and their fabrication substrate which will allow integration within other freeform fabricated devices. We have produced simple IPMC’s using our multiple material freeform fabrication system, and have demonstrated operation in air for more than 40 minutes and 256 bidirectional actuation cycles. The output stress scaled to input power is two orders of magnitude inferior to that of the best reported performance for devices produced in the traditional manner, but only slightly inferior to devices produced in a more similar manner. Possible explanations and paths to improvement are presented. Freeform fabrication of complete electroactive polymer actuators in unusual geometries, with tailored actuation behavior, and integrated with other freeform fabricated active components, will enable advances in biomedical device engineering, biologically inspired robotics, and other fields. This work constitutes the first demonstration of complete, functional, IPMC actuators produced entirely by freeform fabrication.Mechanical Engineerin

Application of Machine Learning Methods to the Open-Loop Control of a Freeform Fabrication System

Freeform fabrication of complete functional devices requires the fabrication system to achieve well-controlled deposition of many materials with widely varying material properties. In a research setting, material preparation processes are not highly refined, causing batch property variation, and cost and time may prohibit accurate quantification of the relevant material properties, such as viscosity, elasticity, etc. for each batch. Closed-loop control based on the deposited material road is problematic due to the difficulty in non-contact measurement of the road geometry, so a labor-intensive calibration and open-loop control method is typically used. In the present work, k-Nearest Neighbor and Support Vector Machine (SVM) machine learning algorithms are applied to the problem of generating open-loop control parameters which produce desired deposited material road geometry from a description of a given material and tool configuration comprising a set of qualitative and quantitative attributes. Training data for the algorithms is generated in the course of ordinary use of the SFF system as the results of manual calibration of control parameters. Given the large instance space and the small training data set compiled thus far, the performance is quite promising, although still insufficient to allow complete automation of the calibration process. The SVM-based approach produces tolerable results when tested with materials not in the training data set. When control parameters produced by the learning algorithms are used as a starting point for manual calibration, significant operator time savings and material waste reduction may be achieved.Mechanical Engineerin

Printing Embedded Circuits

Automated manufacturing technologies such as freeform fabrication can greatly reduce the cost and complexity of infrastructure required to manufacture unique devices or invent new technologies. Multi-material freeform fabrication processes under development have the potential to automatically build complete functional devices including electronics. Making this technology available to creative individuals will revolutionize art and invention, but requires extensive simplification and cost reduction of what is still a laboratory technology. The combination of a Fab@Home Model 1 personal fabrication system and commercially available materials allows the demonstration of simple and inexpensive freeform fabrication of functional embedded electrical circuits, and useful devices. Using this approach, we have been able to demonstrate an LED flashlight, functional printed circuit boards in 2-dimensions and 3- dimensions that are actually entirely printed, and a child’s toy with embedded circuitry. These results, and the materials and methods involved in producing them will be presented in detail.Mechanical Engineerin

Popular Music and Art-interpretive Injustice

It has been over two decades since Miranda Fricker labeled epistemic injustice, in which an agent is wronged in their capacity as a knower. The philosophical literature has proliferated with variants and related concepts. By considering cases in popular music, we argue that it is worth distinguishing a parallel phenomenon of art-interpretive injustice, in which an agent is wronged in their creative capacity as a possible artist. In section 1, we consider the prosecutorial use of rap lyrics in court as a central case of this injustice. In section 2, we distinguish art-interpretive injustice from other categories already discussed in recent literature. In section 3, we discuss the relationship between genre discourse and identity prejudice. The case for recognizing the category of art-interpretive injustice is that it allows one to recognize a class of harms as being importantly related in ways that one would otherwise overlook

Printing Food

This paper examines the possible applications of food as a raw material in freeform fabrication, and provides several demonstrations of edible three-dimensional objects. The use of edible materials offers several advantages: First, it opens the door to the application of SFF technology in custom food industry, such as manufacturing of complex confections with specialized geometries and intricate material compositions. For pedagogical purposes, edible materials provide an easily accessible, nontoxic and low cost way to experiment with rapid prototyping techniques using educational systems such as Fab@Home. For more traditional SFF technologies, food materials with appropriate rheological properties can serve as sacrificial, bio-degradable, bio-compatible or recyclable materials for structural support and draft-printing. We have used the Fab@Home personal fabrication system to produce multi-material edible 3D objects with cake frosting, chocolate, processed cheese, and peanut butter. These are just indicative of the range of potential edible materials and applications.Mechanical Engineerin

Modal Insurance: Probabilities, Risk, and Degrees of Luck

Many widely divergent accounts of luck have been offered or employed in discussing an equally wide range of philosophical topics. We should, then, expect to find some unified philosophical conception of luck of which moral luck, epistemic luck, and luck egalitarianism are species. One of the attempts to provide such an account is that offered by Duncan Pritchard, which he refers to as the modal account. This view commits us to calling an event lucky when it obtains in this world, but fails to obtain in a wide class of nearby possible worlds. In support of this account, Pritchard argues that a theory of luck ought to capture the fact that luck comes in degrees and that luck is closely associated with risk. I argue against this claim by suggesting that an understanding of luck grounded in considerations of probability is better able to satisfy these demands, and that the probability theory better explains exemplary cases of luck like those brought up by Pritchard

On the Oddly Satisfying

In this paper, I propose a novel theory for why we find certain mundane everyday experiences, objects, and phenomena satisfying aesthetic experiences. I refer to these as 'oddly satisfying' experiences, and argue that they assert themselves as aesthetic by being suggestive of the cinematic. This cinematic quality is the product of everyday experiences gesturing towards a kind of careful artistic intent

Country Music and the Problem of Authenticity

In the small but growing literature on the philosophy of country music, the question of how we ought to understand the genre’s notion of authenticity has emerged as one of the central questions. Many country music scholars argue that authenticity claims track attributions of cultural standing or artistic self-expression. However, careful attention to the history of the genre reveals that these claims are simply factually wrong. On the basis of this, we have grounds for dismissing these attributions. Here, I argue for an alternative model of authenticity in which we take claims about the relative authenticity of country music to be evidence of ‘country’ being a dual character concept in the same way that it has been suggested of punk rock and hip-hop. Authentic country music is country music that embodies the core value commitments of the genre. These values form the basis of country artists’ and audiences’ practical identities. Part of country music’s aesthetic practice is that audiences reconnect with, reify, and revise this common practical identity through identification with artists and works that manifest these values. We should then think of authenticity discourse within country music as a kind of game within the genre’s practice of shaping and maintaining this practical identity

The Problem of Genre Explosion

Genre discourse is widespread in appreciative practice, whether that is about hip-hop music, romance novels, or film noir. It should be no surprise then, that philosophers of art have also been interested in genres. Whether they are giving accounts of genres as such or of particular genres, genre talk abounds in philosophy as much as it does the popular discourse. As a result, theories of genre proliferate as well. However, in their accounts, philosophers have so far focused on capturing all of the categories of art that we think of as genres and have focused less on ensuring that only the categories we think are genres are captured by those theories. Each of these theories populates the world with far too many genres because they call a wide class of mere categories of art genres. I call this the problem of genre explosion. In this paper, I survey the existing accounts of genre and describe the kinds of considerations they employ in determining whether a work is a work of a given genre. After this, I demonstrate the ways in which the problem of genre explosion arises for all of these theories and discuss some solutions those theories could adopt that will ultimately not work. Finally, I argue that the problem of genre explosion is best solved by adopting a social view of genres, which can capture the difference between genres and mere categories of art