scholarly journals Active Grasping Control of Virtual-Dexterous-Robot Hand with Open Inventor

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Jinbao Chen ◽  
Dong Han ◽  
Zhuang Peng
Keyword(s):  
Collision Detection ◽  
Target Object ◽  
Tree Structure ◽  
Contact Friction ◽  
Contact Deformation ◽  
Simulation Experiments ◽  
Virtual Force ◽  
Open Inventor ◽  
Virtual Grasping ◽  
Force Calculation

The grasping technology of the virtual-dexterous-robot (VDR) hand plays a key role in the teleoperation of the space robot. For a grasp task in the virtual environment, the collision detection and virtual force calculation need to be implemented. Firstly, a tree-structure virtual scene including a VDR hand and a target object is built up with open inventor (OIV). Secondly, the collision manager provided by OIV is used for collision detection and the oriented bounding box (OBB) is adopted to improve the real-time performance of collision detection. Thirdly, an algorithm is proposed for calculating the virtual force by using the contact deformation. And the contact deformation is calculated according to the transformation matrix between the coordinate systems of the two contact objects. Furthermore, the contact friction is also calculated by this matrix. Considering the virtual force, the modified stable grasping conditions are proposed which are suitable for the virtual grasping. Then a method is proposed for implementing the grasp or release operation by translating different nodes in the tree-structure scene, which can avoid destroying the tree structure. Finally, the viability and effectiveness of the proposed algorithms are proved by simulation experiments.

scholarly journals Briquetting of structurally inhomogeneous porous materials

2020 ◽  
Vol 65 (2) ◽  
pp. 205-214
Author(s):  
O. M. Dyakonov
Keyword(s):  
Porous Body ◽  
Pressure Coefficient ◽  
Energy Condition ◽  
Contact Friction ◽  
Equilibrium Equations ◽  
Friction Forces ◽  
Pressing Process ◽  
Deformation Work ◽  
Pressure Stress ◽  
Force Calculation

The work is devoted to solving the axisymmetric problem of the theory of pressing porous bodies with practical application in the form of force calculation of metallurgical processes of briquetting small fractional bulk materials: powder, chip, granulated and other metalworking wastes. For such materials, the shape of the particles (structural elements) is not geometrically correct or generally definable. This was the basis for the decision to be based on the continual model of a porous body. As a result of bringing this model to a two-dimensional spatial model, a closed analytical solution was obtained by the method of jointly solving differential equilibrium equations and the Guber–Mises energy condition of plasticity. The following assumptions were adopted as working hypotheses: the normal radial stress is equal to the tangential one, the lateral pressure coefficient is equal to the relative density of the compact. Due to the fact that the problem is solved in a general form and in a general formulation, the solution itself should be considered as methodological for any axisymmetric loading scheme. The transcendental equations of the deformation compaction of a porous body are obtained both for an ideal pressing process and taking into account contact friction forces. As a result of the development of a method for solving these equations, the formulas for calculating the local characteristics of the stressed state of the pressing, as well as the integral parameters of the pressing process are derived: pressure, stress, and deformation work.

A Spring Model for Whole-Hand Virtual Grasping

2006 ◽  
Vol 15 (1) ◽  
pp. 47-61 ◽  
Author(s):  
Christoph W. Borst ◽  
Arun P. Indugula
Keyword(s):  
Collision Detection ◽  
Force Feedback ◽  
User Behavior ◽  
Prototype System ◽  
Spring Model ◽  
Hand Model ◽  
Physically Based ◽  
Grasping And Manipulation ◽  
Virtual Grasping ◽  
Object Models

We present a physically-based approach to grasping and manipulation of virtual objects that produces visually realistic results, addresses the problem of visual inter-penetration of hand and object models, and performs force rendering for force-feedback gloves, in a single framework. Our approach couples a simulation-controlled articulated hand model to tracked hand configuration using a system of linear and torsional virtual spring-dampers. We discuss an implementation of our approach that uses a widely available simulation tool for collision detection and response. We pictorially illustrate the resulting behavior of the virtual hand model and of grasped objects, discuss user behavior and difficulties encountered, and show that the simulation rate is sufficient for control of current force-feedback glove designs. We also present a prototype system for natural whole-hand interactions in a desktop-sized workspace.

scholarly journals Force calculation of the process of briquetting powder, chip and other bulk materials

2019 ◽  
pp. 118-125
Author(s):  
O. M. Dyakonov
Keyword(s):  
Porous Body ◽  
Pressure Coefficient ◽  
Energy Condition ◽  
Contact Friction ◽  
Equilibrium Equations ◽  
Bulk Materials ◽  
Friction Forces ◽  
Pressing Process ◽  
Deformation Work ◽  
Force Calculation

The work is devoted to solving the axisymmetric problem of the theory of pressing porous bodies with practical application in the form of force calculation of metallurgical processes of briquetting small fractional bulk materials: powder, chip, granulated and other metalworking wastes. For such materials, the shape of the particles (structural elements) is not geometrically correct or generally definable. This was the basis for the decision to be based on the continual model of a porous body. As a result of bringing this model to a two-dimensional spatial model, a closed analytical solution was obtained by the method of jointly solving differential equilibrium equations and the Guber-Mises energy condition of plasticity. The following assumptions were adopted as working hypotheses: the radial shear stress is equal to the tangential one, the lateral pressure coefficient is equal to the relative density of the compact. Due to the fact that the problem is solved in a general form and in a general formulation, the solution itself should be considered as methodological for any axisymmetric loading scheme. The transcendental equations of the deformation compaction of a porous body are obtained both for an ideal pressing process and taking into account contact friction forces. As a result of the development of a method for solving these equations, the formulas for calculating the local characteristics of the stressed state of the pressing, as well as the integral parameters of the pressing process are derived: pressure, stress, and deformation work.

scholarly journals UnrealHaptics: Plugins for Advanced VR Interactions in Modern Game Engines

2021 ◽  
Vol 2 ◽  
Author(s):  
Janis Rosskamp ◽  
Hermann Meißenhelter ◽  
Rene Weller ◽  
Marc O. Rüdel ◽  
Johannes Ganser ◽  
...  
Keyword(s):  
Collision Detection ◽  
State Of The Art ◽  
Haptic Rendering ◽  
Use Cases ◽  
Use Case ◽  
The Core ◽  
Multiple Contacts ◽  
Game Engines ◽  
Virtual Grasping ◽  
Second Use

We present UnrealHaptics, a plugin-architecture that enables advanced virtual reality (VR) interactions, such as haptics or grasping in modern game engines. The core is a combination of a state-of-the-art collision detection library with support for very fast and stable force and torque computations and a general device plugin for communication with different input/output hardware devices, such as haptic devices or Cybergloves. Our modular and lightweight architecture makes it easy for other researchers to adapt our plugins to their requirements. We prove the versatility of our plugin architecture by providing two use cases implemented in the Unreal Engine 4 (UE4). In the first use case, we have tested our plugin with a haptic device in different test scenes. For the second use case, we show a virtual hand grasping an object with precise collision detection and handling multiple contacts. We have evaluated the performance in our use cases. The results show that our plugin easily meets the requirements of stable force rendering at 1 kHz for haptic rendering even in highly non-convex scenes, and it can handle the complex contact scenarios of virtual grasping.

Man-Computer Derivations of Tree Structure from Multivariate Data

1968 ◽  
Author(s):  
Gerald H. Shure ◽  
Laurence I. Press ◽  
Miles S. Rogers
Keyword(s):  
Multivariate Data ◽  
Tree Structure

Building a tree structure

1976 ◽  
Author(s):  
Patricia Marks Greenfield ◽  
Leslie Schneider
Keyword(s):  
Tree Structure

Analysis of the Contact Deformation of Tread Blocks

1992 ◽  
Vol 20 (4) ◽  
pp. 230-253 ◽  
Author(s):  
T. Akasaka ◽  
K. Kabe ◽  
M. Koishi ◽  
M. Kuwashima
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Deformation Behavior ◽  
Contact Deformation ◽  
The Finite Element Method ◽  
The Road ◽  
Loss Of Contact ◽  
Tread Rubber ◽  
Good Agreement ◽  
Rubber Block

Abstract The deformation behavior of a tire in contact with the roadway is complicated, in particular, under the traction and braking conditions. A tread rubber block in contact with the road undergoes compression and shearing forces. These forces may cause the loss of contact at the edges of the block. Theoretical analysis based on the energy method is presented on the contact deformation of a tread rubber block subjected to compressive and shearing forces. Experimental work and numerical calculation by means of the finite element method are conducted to verify the predicted results. Good agreement is obtained among these analytical, numerical, and experimental results.

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