102,074 research outputs found
Nonlinear modeling and experimental evaluation of fluid-filled soft pads for robotic hands
No full textAfter a brief reminder about previous work, this paper addresses the dynamic characterization of fluid-filled soft pads for robotic hands. The adopted pad specimens are constituted by a single hyper-elastic material having hardness similar to that of the human thumb. The overall pad thickness is then divided into a continuous skin layer and an internal layer having communicating voids which are hermetically sealed and filled with a viscous fluid. Despite a more complicated design, it has been proven [1-3] that the pads present enhanced compliance and damping properties, a lower thickness and a higher surface hardness when compared to previously published solutions. In addition, a quasi-linear model, frequently used to describe the behavior of soft biological tissues can be applied in order to predict and control the pad interaction with the environment during grasping and manipulation tasks. In particular, the experimental tests necessary to evaluate the parameters which determine the pad dynamic response are described and discussed in detail
Progetto concettuale di un robot seriale per il trattamento della Labirintolitiasi
No full textNel presente lavoro viene affrontato con un approccio sistematico il progetto concettuale di un manipolatore seriale per applicazioni mediche, consistenti nella diagnosi e nel trattamento della Labirintolitiasi: si tratta di una comune forma di vertigine, attualmente curata attraverso apposite manovre liberatorie eseguite manualmente dal medico specialista che muove il capo del paziente lungo traiettorie determinate. La metodologia proposta si può applicare in generale per la sintesi topologica e dimensionale di catene cinematiche seriali. Il processo di design viene automatizzato mediante una tecnica di ottimizzazione basata su algoritmi genetici che permette di valutare in maniera oggettiva le performance di ogni possibile configurazione cinematica del manipolatore rispetto a funzioni obiettivo opportunamente definite nelle varie fasi progettuali. Una descrizione della architettura prescelta nel caso del robot per il trattamento della Labirintolitiasi esemplifica i risultati ottenuti
Differentiated layer design to modify the compliance of soft pads for robotic limbs
No full textMost of robotic soft pads studied so far were made with a thick layer of homogeneous material shaped around a rigid core; their behavior has been widely investigated in the literature, mainly under compressive contact load, showing typical non-linear relationship between contact deformation and applied load (the so called power law). This paper proposes differentiated layer design, that is the adoption of a single elastic material, dividing the overall thickness of the pad into layers with different structural design (e.g. a continuous skin layer coupled with an internal layer with voids). The purpose is to modify the actual pad compliance and the resulting power law; in particular, given the material and the allowable pad thickness, to increase the compliance with respect to a non structured pad. Some possible internal layer structures are described, compatible with rapid prototyping manufacturing. Their compressive behaviors are tested and comparatively evaluated showing that the concept can work and be exploited for useful application
Nonlinear modeling and experimental evaluation of fluid-filled soft pads for robotic hands
No full textAfter a brief reminder about previous work, this paper addresses the dynamic characterization of fluid-filled soft pads for robotic hands. The adopted pad specimens are constituted by a single hyper-elastic material having hardness similar to that of the human thumb. The overall pad thickness is then divided into a continuous skin layer and an internal layer having communicating voids which are hermetically sealed and filled with a viscous fluid. Despite a more complicated design, it has been proven [1-3] that the pads present enhanced compliance and damping properties, a lower thickness and a higher surface hardness when compared to previously published solutions. In addition, a quasi-linear model, frequently used to describe the behavior of soft biological tissues can be applied in order to predict and control the pad interaction with the environment during grasping and manipulation tasks. In particular, the experimental tests necessary to evaluate the parameters which determine the pad dynamic response are described and discussed in detail
Bond Graph Modeling And Simulation Of A Constant-Force Dielectric Elastomer Actuator
No full textConstant-Force actuators based on Dielectric Elastomers (DE) can be obtained by coupling a DE film with particular compliant frames whose structural properties must be carefully designed. In any case, the practical achievement of a desired force profile can be quite a challenging task owing to the time-dependent phenomena which affect the DE electromechanical response. Within this scenario, a hyper-viscoelastic model of a rectangular Constant-Force actuator is reported. The model, based on the Bond Graph formalism, can be used as an engineering tool when designing and/or controlling actuators which are expected to work under given nominal conditions. Numerical simulations are provided which predicts the system response to fast changes in activation voltage and actuator position as imposed by an external user
A shift of force vector from arm to brain: 3D computer technology in orthodontic treatment management.
No full textTailoring the viscoelastic properties of soft pads for robotic limbs through purposely designed fluid filled structures
No full textThe majority of soft pads for robotic limbs studied so far were made by visco-elastic polymeric solids whose behavior is significantly influenced by the rate of application of the external loads or displacements. In particular, contact interfaces which are intrinsically visco-elastic are found, for instance, in human fingers and feet or in various robotic devices covered by a compliant surface. An outstanding instance are anthropomorphic hands where time-dependent phenomena profoundly affects the stability and sustainability of the grasp. Alternatively to homogenous solid pads, this paper proposes the use of fluid filled soft structures with differentiated layer design [1] that is the adoption of a single solid material, dividing the overall thickness of the pad into a continuous skin layer coupled with an internal layer having communicating voids. The voids are then hermetically sealed and, in case, filled with fluid. Given the allowable pad thickness, the purpose is to tailor the pad properties to the specific application by 1) selecting a skin material characterized by proper tribological features, 2) designing an inner layer geometry so as to obtain a specific static compliance, 3) filling the pad with a viscous fluid chosen so as to modify time-dependent phenomena and increase damping effects. The proposed concept is validated by designing artificial pads whose viscoelastic properties are either similar or more pronounced when compared to those of the human fingertip
Progetto concettuale di un robot seriale per il trattamento della Labirintolitiasi
No full textNel presente lavoro viene affrontato con un approccio sistematico il progetto concettuale di un manipolatore seriale per applicazioni mediche, consistenti nella diagnosi e nel trattamento della Labirintolitiasi: si tratta di una comune forma di vertigine, attualmente curata attraverso apposite manovre liberatorie eseguite manualmente dal medico specialista che muove il capo del paziente lungo traiettorie determinate. La metodologia proposta si può applicare in generale per la sintesi topologica e dimensionale di catene cinematiche seriali. Il processo di design viene automatizzato mediante una tecnica di ottimizzazione basata su algoritmi genetici che permette di valutare in maniera oggettiva le performance di ogni possibile configurazione cinematica del manipolatore rispetto a funzioni obiettivo opportunamente definite nelle varie fasi progettuali. Una descrizione della architettura prescelta nel caso del robot per il trattamento della Labirintolitiasi esemplifica i risultati ottenuti
Development of the UB hand IV: Overview of design solutions and enabling technologies
No full textThe replication of the human hand's functionality and appearance is one of the main reasons for the development of robot hands. Despite 40 years of research in the field [1], the reproduction of human capabilities, in terms of dexterous manipulation, still seems unachievable by the state-of-the-art technologies. From a design perspective, even defining the optimal functionalities of a robotic end-effector is quite a challenging task since possible applications of these devices span industrial robotics, humanoid robotics, rehabilitation medicines, and prosthetics, to name a few. Therefore, it is reasonable to think that the design solutions, which are well suited to a single domain, might not be readily taken as general guidelines. For example, industrial manipulators are often equipped with basic grippers, which are conceived so as to increase the throughput and the reliability, and are assumed to operate in structured environments. In this case, the enhanced manipulation skills and the subsequent cost increases must be carefully motivated by the application requirements
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