A Novel Origami Inspired Delta Mechanism with Flat Parallelogram Joints

2020 ◽  
pp. 1-22
Author(s):  
Merve Acer Kalafat ◽  
Hasan Sevinc ◽  
Shahrad Samankan ◽  
Atakan Altinkaynak ◽  
Zeynep Temel
Keyword(s):  
Design Methodology ◽  
Small Scale ◽  
Layer By Layer ◽  
Parallel Mechanisms ◽  
End Effector ◽  
High Speeds ◽  
Parallel Movement ◽  
Pick And Place ◽  
Kinematic Models ◽  
Kinematic Performance

Abstract In robotics, origami-based design methodology can be used to create small scale parallel mechanisms with easier assembly processes. Delta mechanisms are one of the famous parallel mechanism used mostly in pick and place operations due to their capability to reach high speeds and accelerations. In this work, we present a novel Delta mechanism fabricated with fully 2D layer by layer methods. In our design we have eliminated manual 3D processes in order to provide parallel movement of the links. We have designed a new flat parallelogram providing pure translations in X-Y-Z directions respecting to the conventional kinematic models for Delta mechanism. The assembly process is reduced to an only cut – laminate – repeat steps which are very basic operations in 2D. The kinematic performance of the mechanism has been analyzed using a 6 DoF position sensor placed on the end-effector. The mechanism has a 20x20x20 mm3 cubic stable workspace with a 17.5 mm radius circular footprint when it is completely flat. The tests were done for circular trajectories having 10 mm radius circles with different heights and circles with different radiuses in a specific height. Despite having no feedback control from the end effector, the mechanism was able to follow the trajectory with 1.5 mm RMS precision. We have also changed the materials of the flexible layers in passive links and presented the trajectory results of the end-effector showing how it effects the kinematic performance of the mechanism.

scholarly journals Design and Kinematic Analysis of a Novel 2-DoF Closed-Loop Mechanism for the Actuation of Machining Robots

2021 ◽  
Author(s):  
Angelica Ginnante ◽  
François Leborne ◽  
Stéphane Caro ◽  
Enrico Simetti ◽  
Giuseppe Casalino
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Parallel Mechanisms ◽  
Serial Manipulators ◽  
Hard Materials ◽  
Serial Robots ◽  
Revolute Joints ◽  
Machining Robot ◽  
Kinematic Models ◽  
Kinematic Performance

Abstract The essential characteristics of machining robots are their stiffness and their accuracy. For machining tasks, serial robots have many advantages such as large workspace to footprint ratio, but they often lack the stiffness required for accurately milling hard materials. One way to increase the stiffness of serial manipulators is to make their joints using closed-loop or parallel mechanisms instead of using classical prismatic and revolute joints. This increases the accuracy of a manipulator without reducing its workspace. This paper introduces an innovative two degrees of freedom closed-loop mechanism and shows how it can be used to build serial robots featuring both high stiffness and large workspace. The design of this mechanism is described through its geometric and kinematic models. Then, the kinematic performance of the mechanism is analyzed, and a serial arrangement of several such mechanisms is proposed to obtain a potential design of a machining robot.

Kinematic analysis and design of a novel 6-degree of freedom parallel robot

2014 ◽  
Vol 229 (2) ◽  
pp. 291-303 ◽  
Author(s):  
DU Hui ◽  
GAO Feng ◽  
PAN Yang
Keyword(s):  
Set Theory ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Design Methodology ◽  
Parallel Robot ◽  
End Effector ◽  
Analysis And Design ◽  
Velocity Models ◽  
Reachable Workspace ◽  
Rotational Motions

A novel 3-UP3R parallel mechanism with six degree of freedoms is proposed in this paper. One most important advantage of this mechanism is that the three translational and three rotational motions are partially decoupled: the end-effector position is only determined by three inputs, while the rotational angles are relative to all six inputs. The design methodology via GF set theory is brought out, using which the limb type can be determined. The mobility of the end-effector is analyzed. After that, the kinematic and velocity models are formulated. Then, workspace is studied, and since the robot is partially decoupled, the reachable workspace is also the dexterous workspace. In the end, both local and global performances are discussed using conditioning indexes. The experiment of real prototype shows that this mechanism works well and may be applied in many fields.

A Statically Balanced Gough/Stewart-Type Platform: Conception, Design, and Simulation

2009 ◽  
Vol 1 (3) ◽  
Author(s):  
Marco Carricato ◽  
Clément Gosselin
Keyword(s):  
Sufficient Conditions ◽  
Parallel Manipulators ◽  
Point Of View ◽  
Theoretical Point ◽  
Constant Force ◽  
Parallel Mechanisms ◽  
End Effector ◽  
Neutral Equilibrium ◽  
The Difference ◽  
Elastic Elements

Gravity compensation of spatial parallel manipulators is a relatively recent topic of investigation. Perfect balancing has been accomplished, so far, only for parallel mechanisms in which the weight of the moving platform is sustained by legs comprising purely rotational joints. Indeed, balancing of parallel mechanisms with translational actuators, which are among the most common ones, has been traditionally thought possible only by resorting to additional legs containing no prismatic joints between the base and the end-effector. This paper presents the conceptual and mechanical designs of a balanced Gough/Stewart-type manipulator, in which the weight of the platform is entirely sustained by the legs comprising the extensible jacks. By the integrated action of both elastic elements and counterweights, each leg is statically balanced and it generates, at its tip, a constant force contributing to maintaining the end-effector in equilibrium in any admissible configuration. If no elastic elements are used, the resulting manipulator is balanced with respect to the shaking force too. The performance of a study prototype is simulated via a model in both static and dynamic conditions, in order to prove the feasibility of the proposed design. The effects of imperfect balancing, due to the difference between the payload inertial characteristics and the theoretical/nominal ones, are investigated. Under a theoretical point of view, formal and novel derivations are provided of the necessary and sufficient conditions allowing (i) a body arbitrarily rotating in space to rest in neutral equilibrium under the action of general constant-force generators, (ii) a body pivoting about a universal joint and acted upon by a number of zero-free-length springs to exhibit constant potential energy, and (iii) a leg of a Gough/Stewart-type manipulator to operate as a constant-force generator.

“Fête de la Soupe”: rural identity, self-representation, and the(re)-making of the village in France

2018 ◽  
Vol 11 (3) ◽  
pp. 296-314 ◽  
Author(s):  
Hélène B. Ducros
Keyword(s):  
Design Methodology ◽  
Rural Setting ◽  
Small Scale ◽  
Content Type ◽  
Rural Identity ◽  
Organizational Challenges ◽  
The Past ◽  
Rural France ◽  
The Village ◽  
Do So

Purpose The purpose of this paper is to explore a grassroot festival in rural France organized around the concept of soup. The annual fête de la soupe held in a village in Auvergne provides a small-scale example of the ways in which space, time and festivalization interact in placemaking. Design/methodology/approach Ethnographic research highlights the motivations and experiences of the organizers and volunteer-participants, as well as some of the organizational challenges. Findings Revealing that the profit motive and economic outcomes are not dominant, this paper shows instead that the fête constitutes a space of relation-building between place and people, between people themselves and an introspective moment over the past and future of place as “rural”. While preserving rurality symbolized and mediated by the exchange of soup as the ultimate peasant dish, the festival is also an opportunity for villagers to revitalize the rural and showcase it as a place of creativity. Originality/value The study addresses the experience of volunteers and organizers in festivals, uses qualitative methods to do so and focuses on festivals in the rural setting, filling three gaps identified by others in the literature.

Kinematic Error Modeling of Delta 3D Printer

2021 ◽  
Vol 1037 ◽  
pp. 77-83
Author(s):  
Andrew V. Kochetkov ◽  
T.N. Ivanova ◽  
Ludmila V. Seliverstova ◽  
Oleg V. Zakharov
Keyword(s):  
Low Cost ◽  
Travel Speed ◽  
Error Modeling ◽  
3D Printer ◽  
Structural Components ◽  
Deterministic Models ◽  
End Effector ◽  
Positioning Errors ◽  
Parallel Movement ◽  
3D Printers

The development of additive manufacturing requires the improvement of 3D printers to increase accuracy and productivity. Delta kinematics 3D printers have advantages over traditional sequential kinematics 3D printers. The main advantage is the high travel speed due to the parallel movement of the platform from three pairs of arms. Another advantage is the relatively low cost due to the small number of structural components. However, delta 3D printers have received limited use. The main reason is the low positioning accuracy of the end effector. Errors in the manufacture and assembly of components of a parallel drive mechanism add up geometrically and cause an error in the position of the end effector. These formulas can be applied to a 3D printer as well. However, well-known studies consider deterministic models. Therefore, the analysis is performed for limiting size errors. The purpose of this article is to simulate the effect of statistical errors in displacements and arm lengths on the positioning errors of a platform with the end effector. The article effectively complements the field of error analysis research and provides theoretical advice on error compensation for delta 3D printer.

scholarly journals Rotation-joint stiffness modeling for industrial robots considering contacts

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401879306 ◽  
Author(s):  
Zhifeng Liu ◽  
Jingjing Xu ◽  
Qiang Cheng ◽  
Yongsheng Zhao ◽  
Yanhu Pei
Keyword(s):  
Fractal Theory ◽  
Joint Stiffness ◽  
Industrial Robots ◽  
Torsional Stiffness ◽  
Equivalent Stiffness ◽  
Force Analysis ◽  
Joint System ◽  
End Effector ◽  
Stiffness Modeling ◽  
High Speeds

Joint flexibility has a major impact on the motion accuracy of a robotic end effector, particularly at high speeds. This work proposes a technique of precisely modeling the torsional stiffness of the rotational joints for the industrial robots. This technique considers the contacts that exist in the joint system, which can have a significant effect on the overall joint stiffness. The torsional stiffness of the connections that commonly exist in the rotational joints, such as the belt connection, the connections using key, bolts, and pins, were modeled by combining the force analysis and the fractal theory. Through modeling the equivalent stiffness for the springs in serial and in parallel, the torsional stiffness of all joints for the ER3A-C60 robot were calculated and analyzed. The results show that the estimated stiffness based on the proposed technique is closer to the actual values than that based on the previous model without considering the contacts. The analysis is useful for controlling the dynamic characteristic of the industrial robots with the rotational joints while planning the trajectory for the end effector.

Examining the impact of political candidates on hotel revenue

2019 ◽  
Vol 3 (1) ◽  
pp. 36-53
Author(s):  
Amanda Belarmino ◽  
Elizabeth A. Whalen
Keyword(s):  
Design Methodology ◽  
The State ◽  
Small Scale ◽  
Structured Interviews ◽  
Political Candidates ◽  
Bandwagon Effect ◽  
Content Type ◽  
Political Candidate ◽  
The Usa ◽  
The Impact

Purpose The purpose of this paper is to examine the impact of a charismatic political candidate on hotel revenue in the USA, particularly in their home states, through the lens of the bandwagon effect. Previous researchers have found that political primaries have a significant impact on hotel revenue due to travel to those states; however, there has yet to be an examination of the impact of popular political candidates on hotel revenue. Design/methodology/approach This research examined the impact of Bernie Sanders’ campaign on hotel revenue in the state Vermont due to the relatively stable demand experienced in that market. First, the researchers used forecasting methodology and t-tests to determine if there was a significant increase in hotel revenue during the time of the Sanders’ campaign for the state and for Burlington, Vermont, his campaign headquarters. Then, eight semi-structured interviews were conducted with hoteliers in Vermont to determine if the Sanders’ campaign was responsible for the observed changes. Findings While the hotel revenue for the state was not significantly different than what would be expected, the hotel revenue in Burlington did see a significant increase. Hoteliers did attribute an increased awareness of the destination and some specific instances of travelers to Sanders’ campaign. Originality/value This is the first study to date to demonstrate the influence of a political candidate on hotel revenue and demonstrated that the bandwagon effect can impact hotel revenue. For hoteliers, it demonstrates that increased destination awareness can impact behavioral intentions on a small scale.

scholarly journals Development of small-scale unmanned hydrofoil boats

2020 ◽  
pp. 1-12
Author(s):  
Noah T. Thompson ◽  
Phillip R. Whitworth ◽  
Konstantin I. Matveev
Keyword(s):  
Small Scale ◽  
Empirical Correlations ◽  
Unmanned Surface Vehicles ◽  
High Speeds ◽  
Carbon Fiber Cloth ◽  
Measuring Module ◽  
Design Calculations ◽  
Semi Empirical ◽  
Maritime Community

Unmanned boats have gained a lot of interest in the maritime community during the last decade. Most hydrodynamic platforms employed for unmanned boats are based on traditional relatively simple hulls. In the present study, small-scale hydrofoil-assisted unmanned boats (0.6–0.7 m in length and 3.5–5.5 kg in mass) have been developed and tested. Design calculations using a hydrodynamic transverse-strip engineering method with semi-empirical correlations were applied to determine suitable dimensions for hydrofoil systems. The boat hulls and hydrofoils were fabricated by laying up carbon-fiber cloth sheets on foam cores or 3-D printed profiles. The boats were instrumented with outboard propulsors and electronic equipment for operations in both remote control and autopilot modes. In addition, an in-situ thrust-measuring module was designed and installed at the hull sterns to gather thrust data at GPS-measured speeds in the range between 0 and 11 m/s. The developed boats proved to be robust platforms capable of going over 600 m distances at high speeds while autonomously following preset paths. The presented methods and results can assist engineers developing unmanned surface vehicles that utilize advanced hydrodynamic concepts.

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