Catching Continuum Between Preshape and Grasping Based on Fluidics

2010 ◽  
Author(s):  
Baris Ozyer ◽  
Ismet Erkmen ◽  
Aydan M. Erkmen
Keyword(s):  
Momentum Transfer ◽  
Minimum Energy ◽  
Fluid Flows ◽  
Robotic Hand ◽  
Robot Hand ◽  
Impact Forces ◽  
Initial Stage ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Fluid Particles

We propose a new fluidics based methodology to determine a continuum between preshaping and grasping so as to appropriately preshape a multifingered robot hand for creating an optimal initialization of grasp, with minimum energy loss towards task execution, upon landing on an object. In this paper, we investigate the effects of impact forces and momentum transfer between different hand preshapes landing on an object. Momentum transfer parameters lead to modification of object orientation and position at the very initial stage of task after that preshaped fingers land on the object. We model fingers as particles in a solidified environment while the medium squeezed by hand preshape that is closing upon an object, is modeled as a compressible fluid where momentum is propagated until hitting the surface of the solidified particle medium of the object. Smoothed particle hydrodynamics model (SPH) is used to simulate the general dynamic of fluid flows and momentum transfer between particles of different media. The fingers of the robotic hand are modeled by solidified fluid particles interacting with compressible surrounding fluids in which objects are defined as rigid-body solidified fluid particles. The developed model has been applied, in this paper, to the simulation of various simple robot hand preshaping and the generated momentum transfer profiles an object surface have been analyzed.

Imitation of Human Body Poses by the Formation Control of a Fluidic Swarm

2012 ◽  
Author(s):  
Umut Tilki ◽  
Ismet Erkmen ◽  
Aydan M. Erkmen
Keyword(s):  
Human Body ◽  
Formation Control ◽  
Fluid Flows ◽  
The Body ◽  
Body Parts ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Fluid Particles ◽  
Control Layer ◽  
Fluid Parameters

Imitation learning is one of the forms of social learning that enables the human or robot agents to learn new skills. The knowledge acquired for imitation can be basically represented as action mapping based on “organ matching” which determines the correspondence between imitator and imitatee, if the imitator and the demonstrator share the same embodiment. In this paper, we aim at imitation of two system with totally different dynamics, imitating each other, where any correspondence is missing. Towards this aim, we adopt a case where the imitator is a fluidic system which dynamics is totally different than the imitatee, that is a human performing different body poses. Our work proposes the fluidics formation control of fluid particles where the formation results from the imitation of observed human body poses. Fluidic formation control layer is responsible of assigning the correct fluid parameters to the swarm formation layer according to the body poses adopted by the human performer. The movement of the fluid particles is modeled using the Smoothed Particle Hydrodynamics (SPH) which is a particle based Lagrangian method for simulation of fluid flows. The region based controller first extract the human body parts generating the regions where the attention is attracted by the imitatee and fits an appropriate ellipses to delimite boundaries of those regions. The ellipse parameters such as center of the ellipses, eccentricity, length of the major and minor axis etc. are used by the fludic layer in order to generate human body poses. This paper introduces our technique and demonstrates the imitation performance of our system.

SPH Analysis for Transient Thermal Stress of FGMs with Temperature-Dependent Properties

2015 ◽  
Vol 1096 ◽  
pp. 297-301
Author(s):  
Gui Ming Rong ◽  
Hiroyuki Kisu
Keyword(s):  
Thermal Stress ◽  
Thermal Conditions ◽  
Functionally Graded ◽  
Temperature Dependent ◽  
Graded Materials ◽  
Initial Stage ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Temperature Dependent Properties ◽  
Transient Thermal

A formulation using the deviatoric stress and the continuity equation is extended to the analysis of the dynamic response of functionally graded materials (FGMs) subjected to a thermal shock by smoothed particle hydrodynamics (SPH), in which temperature dependent properties of materials are considered. Several dynamic thermal stress problems are analyzed to investigate the fluctuation of thermal stress at the initial stage under three types of thermal conditions, with the addition of two kinds of mechanical boundary conditions.

Natural convection from heated fin shapes in a nanofluid-filled porous cavity using incompressible smoothed particle hydrodynamics

2019 ◽  
Vol 29 (12) ◽  
pp. 4569-4597 ◽  
Author(s):  
Abdelraheem M. Aly ◽  
Zehba Raizah ◽  
Mitsuteru Asai
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Smoothed Particle Hydrodynamics ◽  
Fluid Flows ◽  
Content Type ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Incompressible Smoothed Particle Hydrodynamics ◽  
Darcy Parameter

Purpose This study aims to focus on the numerical simulation of natural convection from heated novel fin shapes in a cavity filled with nanofluid and saturated with a partial layer of porous medium using improved incompressible smoothed particle hydrodynamics (ISPH) method. Design/methodology/approach The dimensionless of Lagrangian description for the governing equations were numerically solved using improved ISPH method. The current ISPH method was improved in term of wall boundary treatment by using renormalization kernel function. The effects of different novel heated (Tree, T, H, V, and Z) fin shapes, Rayleigh number Ra(103 – 106 ), porous height Hp (0.2-0.6), Darcy parameter Da(10−5 − 10−1 ) and solid volume fraction ϕ(0.0-0.05) on the heat transfer of nanofluid have been investigated. Findings The results showed that the variation on the heated novel fin shapes gives a suitable choice for enhancement heat transfer inside multi-layer porous cavity. Among all fin shapes, the H-fin shape causes the maximum stream function and Z-fin shape causes the highest value of average Nusselt number. The concentrations of the fluid flows in the nanofluid region depend on the Rayleigh and Darcy parameters. In addition, the penetrations of the fluid flows through porous layers are affected by porous heights and Darcy parameter. Originality/value Natural convection from novel heated fins in a cavity filled with nanofluid and saturated with a partial layer of porous medium have been investigated numerically using improved ISPH method.

scholarly journals An Efficient Sleepy Algorithm for Particle-Based Fluids

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Xiao Nie ◽  
Leiting Chen ◽  
Tao Xiang
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Flow Behavior ◽  
Visual Quality ◽  
Repulsive Force ◽  
Performance Gain ◽  
Weakly Compressible ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Fluid Particles ◽  
Computational Resources

We present a novel Smoothed Particle Hydrodynamics (SPH) based algorithm for efficiently simulating compressible and weakly compressible particle fluids. Prior particle-based methods simulate all fluid particles; however, in many cases some particles appearing to be at rest can be safely ignored without notably affecting the fluid flow behavior. To identify these particles, a novel sleepy strategy is introduced. By utilizing this strategy, only a portion of the fluid particles requires computational resources; thus an obvious performance gain can be achieved. In addition, in order to resolve unphysical clumping issue due to tensile instability in SPH based methods, a new artificial repulsive force is provided. We demonstrate that our approach can be easily integrated with existing SPH based methods to improve the efficiency without sacrificing visual quality.

A Modified Smoothed Particle Hydrodynamics Scheme to Model the Stationary and Moving Boundary Problems for Newtonian Fluid Flows

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Mohammad Sefid ◽  
Rouhollah Fatehi ◽  
Rahim Shamsoddini
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Moving Boundary ◽  
Fluid Flows ◽  
Boundary Problems ◽  
Driven Cavity ◽  
First Case ◽  
Weakly Compressible ◽  
Present Solution ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

A robust modified weakly compressible smoothed particle hydrodynamics (WCSPH) method based on a predictive corrective scheme is introduced to model the fluid flows engaged with stationary and moving boundary. In this paper, this model is explained and practically verified in three distinct laminar incompressible flow cases; the first case involves the lid driven cavity flow for two Reynolds numbers 400 and 1000. The second case is a flow generated by a moving block in the initially stationary fluid. The third case is flow around the stationary and transversely oscillating circular cylinder confined in a channel. These results in comparison with the standard benchmarks also confirm the good accuracy of the present solution algorithm.

scholarly journals A 3D Simulation of a Moving Solid in Viscous Free-Surface Flows by Coupling SPH and DEM

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Liu-Chao Qiu ◽  
Yi Liu ◽  
Yu Han
Keyword(s):  
Free Surface ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Free Surface Flows ◽  
Water Tank ◽  
Surface Flows ◽  
Computational Mesh ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Solid Phases

This work presents a three-dimensional two-way coupled method to simulate moving solids in viscous free-surface flows. The fluid flows are solved by weakly compressible smoothed particle hydrodynamics (SPH) and the displacement and rotation of the solids are calculated using the multisphere discrete element method (DEM) allowing for the contact mechanics theories to be used in arbitrarily shaped solids. The fluid and the solid phases are coupled through Newton’s third law of motion. The proposed method does not require a computational mesh, nor does it rely on empirical models to couple the fluid and solid phases. To verify the numerical model, the floating and sinking processes of a rectangular block in a water tank are simulated, and the numerical results are compared with experimental results reported in published literatures. The results indicate that the method presented in this paper is accurate and is capable of modelling fluid-solid interactions with a free-surface.

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