1,717 research outputs found
Design and Control of Compliant Actuation Topologies for Energy-Efficient Articulated Robots
No full textConsiderable advances have been made in the field of robotic actuation in recent
years. At the heart of this has been increased use of compliance. Arguably the most
common approach is that of Series-Elastic Actuation (SEA), and SEAs have evolved
to become the core component of many articulated robots. Another approach is
integration of compliance in parallel to the main actuation, referred to as Parallel-
Elastic Actuation (PEA). A wide variety of such systems has been proposed. While
both approaches have demonstrated significant potential benefits, a number of key
challenges remain with regards to the design and control of such actuators.
This thesis addresses some of the challenges that exist in design and control of compliant
actuation systems. First, it investigates the design, dynamics, and control of
SEAs as the core components of next-generation robots. We consider the influence of
selected physical stiffness on torque controllability and backdrivability, and propose
an optimality criterion for impedance rendering. Furthermore, we consider disturbance
observers for robust torque control. Simulation studies and experimental data
validate the analyses. Secondly, this work investigates augmentation of articulated
robots with adjustable parallel compliance and multi-articulated actuation for increased
energy efficiency. Particularly, design optimisation of parallel compliance
topologies with adjustable pretension is proposed, including multi-articulated arrangements.
Novel control strategies are developed for such systems. To validate the
proposed concepts, novel hardware is designed, simulation studies are performed,
and experimental data of two platforms are provided, that show the benefits over
state-of-the-art SEA-only based actuatio
The works of the Rev. John Wesley ... with the last corrections of the author.
No full text"List of works revised and abridged from various authors, by the Rev. John Wesley, M. A., with the prefaces": v. 12, p. [199]-318; "List of poetical works published by the Rev. Messrs. John and Charles Wesley, with prefaces": p. [319]-345; "Musical works published by the Reverend John Wesley, M.A.": p. 345-346."Preface to the third edition," dated 1831, v. 1, p. [i]-xvi.Mode of access: Internet
'A local habitation and a name A Kristevan reading of human growth in religion, with a reference to John and Charles Wesley'
Get PDFThis study is concerned with the concept of human growth and change: it juxtaposes processes of growth and change in psychoanalytic therapy and those in a religious context. In both situations the relationship between growth and development and the idea of becoming 'good' is considered. Kleinian, Post-Kleinian and particularly Kristevan theory is used to elucidate facilitators of change in psychoanalytic therapy and in the context of Christian faith. The emphases in the theory used here differ from those of more traditional developmental theorists in the study of religion, which rely heavily on ego-psychology and self-psychology, and focus on the autonomous ego and the degree of maturity of forms of religion. By contrast, the emphases here are on the split self, on unconscious drives, phantasies and affects, and on the non-cognitive apprehension of truth. Through an examination of the lives of John and Charles Wesley, the thesis examines the possibility of growth occurring in the context of so-called 'immature’ forms of religion, the means by which this might occur, and the extent to which change is governed by an individual's mental structure and psychological defences. The Kristevan reading allows a less cognitive, 'ego-driven' study of the growth to 'goodness' than does that of the developmental theorists. It thus questions the validity of traditional classifications of forms of religion. It elicits differences between the historical subjects, which demonstrate the importance of personality factors in facilitating or hindering growth. Finally, it enables an exploration of Charles Wesley’s hymns which reveals evidence of erotic and imaginary elements, and the possibility of triadic openness in what some would see as an 'immature' form of belief. This examination also questions Kristeva's own assertion that religious symbolism cannot adequately 'sublimate' the 'abject'
3D-printable low-reduction cycloidal gearing for robotics
Get PDFThe recent trend towards low reduction gearing in robotic actuation has revitalised the need for high-performance gearing concepts. In this work we propose compact low-reduction cycloidal gearing, that is 3D-printable and combined with off-the-shelf components. This approach presents an enormous potential for high performance-to-cost implementations. After discussing parameter selection and design considerations, we present a prototype that is combined with a low-cost brushless motor to demonstrate its potential. Extensive experimental results demonstrate high performance, including >40Nm torque, low friction and play, and high impact robustness. The results show that the proposed approach can yield viable gearbox designs
The Scripture doctrine concerning predestination, election and reprobation. Extracted from a late author. By John Wesley, M.A. Fellow of Lincoln College, Oxford. ; [Three lines from I. Timothy]
No full text16 p.Attributed to John Wesley by Evans
John Wesley and Methodist music in the eighteenth century : principles and practice
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Letter from Dillon Wesley Throckmorton, Minister, Trinity Methodist Church, to Caleb Foote, 1942
No full textLetter from Dillon Wesley Throckmorton to Caleb Foote: "1. The Japanese families here are anxious to be evacuated and resettled together, to that end we have place_ a plea with the W.C.C.A. That means I have no families for you to suggest to mid-west FOR folk. 2. The list will be sent you soon. Miss Round promised me Tuesday night she would get it out to you right away. Some time she is a bit slow doing things. I have written a letter announcing the next meeting for her. 3. The Methodist Aid committee for the Japanese Evacuation which we formed here last week has already done several small things to stone for the sins of our time, with the Japanese people. We have some real heart breaks here. I think I have answered the three requests. Funds seem to be a great difficulty with us. Some send direct to the N.Y. office, etc., others feel that we must do something here for a few needy cases, so we have been unable to send any your way yet. I know when they get your news sheet they will want to help however so getting the list to you right away is important. Success and service to you, Dillon."Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Sanitizing Product Contact Surfaces for Fresh Produce Production
No full textDiscussion of how to properly sanitize product contact surfaces in a farm environment
Experimental comparison of pinwheel and non-pinwheel designs of 3D-printed cycloidal gearing for robotics
Get PDFRecent trends in robotic actuation have highlighted the need for low cost, high performance, and efficient gearing. We present an experimental study comparing pinwheel and non-pinwheel designs of cycloidal gearing. The open source designs are 3D-printable, combined with off-the-shelf components, achieving a high performance-to-cost ratio. Extensive experimental data is presented, that compares two prototypes on run-in behaviour and a number of quantitative metrics including transmission error, play, friction, and stiffness. Furthermore, we assess overall actuator performance through position control experiments, and a 10-hour endurance test. The results show strong performance characteristics, and crucially, suggest that non-pinwheel designs of cycloidal gearing can be a lower complexity and cost alternative to classical pinwheel designs, while offering similar performance.</p
Modeling and Control of Adjustable Articulated Parallel Compliant Actuation Arrangements in Articulated Robots
No full textConsiderable advances in robotic actuation technology have been made in recent years. Particularly the use of compliance has increased, both as series elastic elements as well as in parallel to the main actuation drives. This work focuses on the model formulation and control of compliant actuation structures including multiple branches and multiarticulation, and significantly contributes by proposing an elegant modular formulation that describes the energy exchange between the compliant elements and articulated multibody robot dynamics using the concept of power flows, and a single matrix that describes the entire actuation topology. Using this formulation, a novel gradient descent based control law is derived for torque control of compliant actuation structures with adjustable pretension, with proven convexity for arbitrary actuation topologies. Extensions toward handling unidirectionality of elastic elements and joint motion compensation are also presented. A simulation study is performed on a 3-DoF leg model, where series-elastic main drives are augmented by parallel elastic tendons with adjustable pretension. Two actuation topologies are considered, one of which includes a biarticulated tendon. The data demonstrate the effectiveness of the proposed modeling and control methods. Furthermore, it is shown the biarticulated topology provides significant benefits over the monoarticulated arrangement
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