scholarly journals Kinematic Analysis of a Mechanism With Dual Remote Centre of Motion and its Potential Application

Author(s):  
Guochao Bai ◽  
Peng Qi ◽  
Kaspar Althoefer ◽  
Duanling Li ◽  
Xianwen Kong ◽  
...  

Development of a mechanism with dual remote center of motion (dual-RCM mechanism) intended for teleoperated ophthalmic surgery is reported in this paper. First, characteristics of RCM mechanisms are analyzed. Then, a method to synthesize dual-RCM mechanisms is proposed. Further the mechanical design parameters are optimized to synthesize types of mechanisms meeting functional requirements as well as workspace constraints. The dual-RCM mechanism intended for teleoperated ophthalmic surgery includes two end-effectors: one provides the tool insertion, the other tracks eye movement. The superiority is embodied in the self-synchronized motion of double end-effectors, which allows RCM point of the working instrument to track the penetration point real-time, thereby enhancing microsurgical accuracy. In the proposed implementation, a conceptual helmet mechanical architecture integrating surgical tools with triple-parallelogram linkages is introduced to release the surgeon’s hands by enabling more robotic technologies during the procedures. The vision of the research is to help revolutionize the ophthalmic surgical procedures from bimanual fashion to master-slave teleoperation.

Author(s):  
Patrik Boart ◽  
Ola Isaksson

Currently, mechanical design of aero engine structural components is defined by dimensioning of Design Parameters (DP's) to meet Functional Requirements (FR's). FR's are typically loads, geometrical interfaces and other boundary conditions. Parameters from downstream processes are seldom actually seen as DP's. This paper proposes that downstream process parameters are treated as DP's which calls for engineering methods that can define and evaluate these extended set of DP's. Using the proposed approach manufacturing process alternatives can be used as DP's in early stages of product development. Both the capability to quantitatively assess impact of varying manufacturing DP's, and the availability of these design methods are needed to succeed as an early phase design method. One bottleneck is the preparation time to define and generate these advanced simulation models. This paper presents how these manufacturing process simulations can be made available by automating the weld simulation preparation stages of the engineering work. The approach is based on a modular approach where the methods are defined with knowledge based engineering techniques-operating close to the CAD system. Each method can be reused and used independently of each other and adopted to new geometries. A key advantage is the extended applicability to new products, which comes with a new set of DP's. On a local level the lead time to generate such manufacturing simulation models is reduced with more than 99% allowing manufacturing process alternatives to be used as DP's in early stages of product development.


2018 ◽  
Vol 223 ◽  
pp. 01024
Author(s):  
Danielle M. Vossebeld ◽  
Joseph T. Foley ◽  
Erik Puik

Axiomatic Design and Complexity Theory as described by Suh focus heavily on the coupling often found in functional requirements. This is so fundamental to the analysis of the design that it is the core of the Axiom of Independence which examines the coupling between functional requirements due to chosen design parameters. That said, the mapping between customer needs and functional requirements is often overlooked. In this paper we consider coupling, found due to this mapping, as a possible source of complexity in terms of a user interface to a designed product. We also re-examine the methodology of how customer needs are generated and translated into the other domains to understand how they can give further insight into the customer mindset. Based on this analysis, we believe customer domain complexity should always be examined in design that includes end-user interaction.


Author(s):  
John D. Watton ◽  
James R. Rinderle

The complexity of mechanical design is reflected in the complexity of the design constraints which relate functional requirements to design parameters. Reformulations of the design constraints can significantly reduce this complexity. This is accomplished by a transformation to alternative design parameters, such as a critical ratio, a non-dimensional parameter, or a simple difference; e.g. the ratio of surface area to volume for heat transfer loss, the Reynold's number in fluid mechanics, or the velocity difference across a fluid coupling. We have developed a method by which the alternative parameters are chosen for physical significance and for the ability to create a more direct correspondence to functional behavior as determined by measures of serial and block decomposability of the constraints. Rules have been developed for the creation of physically significant new parameters from the algebraic combination of the original parameters. The rules are based on engineering principles and rely on knowledge about what a parameter physically represents rather than other qualities such as dimensions. A computer based system, called EUDOXUS, has been developed to automate this procedure. The system operates on a set of design constraints to produce sets of transformed constraints in terms of alternative design parameters. The method and its implementation have demonstrated successful results for many highly nonlinear and highly coupled parameterized designs from many mechanical engineering domains.


Author(s):  
Silvia Frumento ◽  
Rinaldo C. Michelini ◽  
Rainer Konietschke ◽  
Ulrich Hagn ◽  
Tobias Ortmaier ◽  
...  

The development of a remotely operated, Co-Robotic Positioning Device (CRPD) for instrumental backing and optimal base position to robotic arms in tele-surgery is discussed. To optimise the setting of robotic operating rooms (ROR) by reducing the structures’ size around the patient and by selecting task-driven layouts, the design of a hanging servo-carrier coming from the ceiling is chosen, rather than a device located on the floor. The present study prospects a split-duty approach, distinguishing the Co-Robotic Positioning Device, CRPD, from the front-end effectors, each subsystem hierarchically controlled by remote location, in keeping with optimal protocols. The attention is focused on the slave-carrier, to establish an optimal design of the CRPD, based on the characteristics of robotic effectors and the surgical task. The CRPD is conceived to support (up to four) robotic effectors, each one equipped with proper tools (endoscope, scalpels, scissors, suture needles, etc.). The CRPD, actually, by optimally positioning the robotic arms, avoids the need of manual deployment, in current setups often necessary to avoid singularities or collisions. The Automatic Changing Device for Surgical Tools, ACD-ST, is another significant device of the conceived slave-carrier. It allows the tele-operating surgeon to change the tools (scalpels, scissors, etc.) by a direct command from his console. Example applications aim at ticklish endoscopic/tomic operations that require high accuracy with low involved forces such as cardio-thoracic-surgery, abdominal surgery, spine-surgery, microsurgery (neurosurgery, hand-surgery, ophthalmic-surgery, ear-nose-throat surgery), say, the typical domains of MIRS, where robotic surgery is quickly expanding.


Author(s):  
John D. Watton ◽  
James R. Rinderle

Abstract The complexity of mechanical design is reflected in the complexity of the design equations which relate functional requirements to design parameters. Reformulations of the design equations can significantly reduce this complexity. This is accomplished by a transformation to alternative design parameters, such as a critical ratio, a nondimensional parameter, or a simple difference; e.g. the ratio of surface area to volume for heat transfer loss, the Reynold’s number in fluid mechanics, or the velocity difference across a fluid coupling. We have developed a method by which the alternative parameters are chosen for physical significance and for the ability to create a more direct correspondence to functional behavior as determined by measures of serial and block decomposability of the constraints. Rules have been developed for the creation of physically significant new parameters from the algebraic combination of the original parameters. The rules are based on engineering principles and rely on knowledge about what a parameter physically represents rather than other qualities such as dimensions. A computer based system, called EUDOXUS, has been developed to automate this procedure. The system operates on a set of design constraints to produce sets of transformed constraints in terms of alternative design parameters. The method and its implementation have demonstrated successful results for many highly nonlinear and highly coupled parameterized designs from many mechanical engineering domains.


2019 ◽  
Vol 78 (1-2) ◽  
pp. 69-75 ◽  
Author(s):  
Mikaël De Clercq ◽  
Charlotte Michel ◽  
Sophie Remy ◽  
Benoît Galand

Abstract. Grounded in social-psychological literature, this experimental study assessed the effects of two so-called “wise” interventions implemented in a student study program. The interventions took place during the very first week at university, a presumed pivotal phase of transition. A group of 375 freshmen in psychology were randomly assigned to three conditions: control, social belonging, and self-affirmation. Following the intervention, students in the social-belonging condition expressed less social apprehension, a higher social integration, and a stronger intention to persist one month later than the other participants. They also relied more on peers as a source of support when confronted with a study task. Students in the self-affirmation condition felt more self-affirmed at the end of the intervention but didn’t benefit from other lasting effects. The results suggest that some well-timed and well-targeted “wise” interventions could provide lasting positive consequences for student adjustment. The respective merits of social-belonging and self-affirmation interventions are also discussed.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.


2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Tamara Feldman

This paper is a contribution to the growing literature on the role of projective identification in understanding couples' dynamics. Projective identification as a defence is well suited to couples, as intimate partners provide an ideal location to deposit unwanted parts of the self. This paper illustrates how projective identification functions differently depending on the psychological health of the couple. It elucidates how healthier couples use projective identification more as a form of communication, whereas disturbed couples are inclined to employ it to invade and control the other, as captured by Meltzer's concept of "intrusive identification". These different uses of projective identification affect couples' capacities to provide what Bion called "containment". In disturbed couples, partners serve as what Meltzer termed "claustrums" whereby projections are not contained, but imprisoned or entombed in the other. Applying the concept of claustrum helps illuminate common feelings these couples express, such as feeling suffocated, stifled, trapped, held hostage, or feeling as if the relationship is killing them. Finally, this paper presents treatment challenges in working with more disturbed couples.


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