Algorithmic Selection of Preferred Grasp Poses using Manipulability Ellipsoid Forms

2021 ◽  
pp. 1-24
Author(s):  
Rajesh Kumar ◽  
Sudipto Mukherjee
Keyword(s):  
Geodesic Distance ◽  
Object Surface ◽  
Kinematic Constraints ◽  
Rolling Contacts ◽  
Manipulability Measure ◽  
Robotic Grasp ◽  
Selection Of

Abstract An algorithm to search for a kinematically desired robotic grasp pose with rolling contacts is presented. A manipulability measure is defined to characterise the grasp for multi-fingered robotic handling. The methodology can be used to search for the goal grasp pose with a manipulability ellipsoid close to the desired one. The proposed algorithm is modified to perform rolling based relocation under kinematic constraints of the robotic fingertips. The search for the optimal grasp pose and the improvement of the grasp pose by relocation is based on the reduction of the geodesic distance between the current and the target manipulability matrices. The algorithm also derives paths of the fingertip on the object surface in order to achieve the goal pose. An algorithmic option for the process of searching for a suitable grasp configuration is hence achieved.

Workspace Evaluation of Stewart Platforms

1992 ◽  
Author(s):  
Oren Masory ◽  
Jian Wang
Keyword(s):  
Stewart Platform ◽  
Design Tool ◽  
Kinematic Constraints ◽  
Stewart Platforms ◽  
Selection Of

Abstract The workspace and the dexterity of a Stewart Platform are effected by the choice of its major dimensions, actuators’ stroke and the kinematic constraints of its joints. An investigation of the effects of these parameters on workspace volume of the platform is presented. The obtained results were normalized so that these can be used as a design tool for the selection of dimensions, joints and actuators.

Automating the Appending of Image Information to Grid Map Corresponding to Object Shape

2017 ◽  
Vol 29 (4) ◽  
pp. 713-719
Author(s):  
Tomohito Takubo ◽  
◽  
Hironobu Takaishi ◽  
Atsushi Ueno
Keyword(s):  
Optimization Method ◽  
Mapping Method ◽  
Set Covering ◽  
Covering Problem ◽  
Inspection System ◽  
Object Surface ◽  
Object Shape ◽  
Image Information ◽  
Grid Map ◽  
Selection Of

A technique for automating the Image-Information-Added Map, a mapping method for photographing an object at a required resolution, is proposed. The picture shooting vector indicating the angle for taking a picture with sufficient resolution is defined according to the shape of the object surface, and the operator controls a robot remotely to acquire pictures by checking the picture shooting vector in our previous study. For an automated inspection system, image acquisition should be automated. Assuming a 2-D grid map is prepared, first, the shooting vectors are set on the surface of the object in the map, and the picture shooting areas are defined. In order to reduce the number of the points that the mobile robot moves to to take pictures, an overlapping picture shooting area should be selected. As the selection of the points where pictures are taken is a set covering problem, the ant colony optimization method is used to solve it. Edge Exchange Crossover (EXX) is used to select picture taking points that are connected for efficient checking. The proposed method is implemented in a robot and evaluated according to the resolution of the collected images in an experimental environment.

scholarly journals An overview on the Brazilian orange juice production chain

2013 ◽  
Vol 35 (1) ◽  
pp. 218-225 ◽  
Author(s):  
Renato Marcio dos Santos ◽  
Irenilza de Alencar Nääs ◽  
Mario Mollo Neto ◽  
Oduvaldo Vendrametto
Keyword(s):  
Social Network ◽  
Orange Juice ◽  
Geodesic Distance ◽  
Logistic Distribution ◽  
Processing Industry ◽  
Production Chain ◽  
The Social ◽  
International Price ◽  
Market Preference ◽  
Selection Of

Brazil is the world's largest producer of oranges and uses more than 70% of the harvested fruits in the production of juices. The amount of processed orange is growing about 10% per year, confirming the trend of the Brazilian citrus for juice production. This research aimed to investigate the Brazilian orange juice production chain from 2005 to 2009. Data from the amount of frozen juice produced and exported, international price of orange juice, and intermediate transactions were assessed in order to make possible selection of all interveners involved in the chain. The study using the Social Network Analysis (SNA) showed that the densest relationships in the network are from exporters to importers and from orange growers to the orange processing industry. No difference was found in the values of the network geodesic distance or the clustering coefficients from 2005 to 2009. The degree of centrality increased steadily throughout the years indicating that the processing industry attempts to minimize the risks by centralizing the actions. A decrease in export of orange juice from 2007 (2.07 10(6) t) to 2008 (2.05 10(6) t) was found, probably due to the world's financial crisis with recovery in 2009. Since 2004, there has been an increase of nearly 10% per year in the market preference of concentrate juice (OFCJ) when compared to the "not from concentrated" juice (NFC). Nowadays the NFC market represents nearly 50% of all Brazilian export which impacted in the logistic distribution and transportation issues.

New advances in automatic selection of eligible surface elements for grasping and fixturing

Robotica ◽  
2009 ◽  
Vol 28 (3) ◽  
pp. 341-348 ◽  
Author(s):  
Y. Zheng ◽  
W.-H. Qian
Keyword(s):  
General Condition ◽  
Point Contact ◽  
Point Contacts ◽  
Object Surface ◽  
Quantitative Criterion ◽  
Grasp Planning ◽  
Line Segments ◽  
Force Closure ◽  
Soft Finger ◽  
Selection Of

SUMMARYMany object surfaces involve a number of pieces, expressed by different equations. Previous methods of optimal grasp planning can hardly cope with such cases. Ding et al. solve this problem by characterizing the object surface with convex facets and discrete points, then selecting the eligible ones for force-closure, and finally seeking the optimal contact positions on the selected elements. So far, however, no point contact with friction (PCwF) but only frictionless point contacts (FPC) can be used on the facets, while soft finger contacts (SFC) are excluded at all. In this paper, to the above two surface elements we add line segments. Moreover, the limitations on the contact types are completely removed. A general condition and a quantitative criterion of eligibility are presented, followed by a heuristic algorithm and an iterative algorithm for finding the better eligible elements. Three common examples show: the new advances make the formerly tough problems smoothly solvable.

scholarly journals Manipulation Planning for Large Objects through Pivoting, Tumbling, and Regrasping

2021 ◽  
Vol 11 (19) ◽  
pp. 9103
Author(s):  
Ang Zhang ◽  
Keisuke Koyama ◽  
Weiwei Wan ◽  
Kensuke Harada
Keyword(s):  
Object Manipulation ◽  
Robotic Manipulation ◽  
Limited Area ◽  
Object Surface ◽  
Manipulation Planning ◽  
Kinematic Constraints ◽  
Unstable Support ◽  
End Effectors ◽  
Set Of Points ◽  
Dual Arm

Robotic manipulation of a bulky object is challenging due to the limited kinematics and payload of the manipulator. In this study, a robot realizes the manipulation of general-shaped bulky objects utilizing the contact with the environment. We propose a hierarchical manipulation planner that effectively combined three manipulation styles, namely, pivoting, tumbling, and regrasping. In our proposed method, we first generate a set of superimposed planar segments on the object surface to obtain an object pose in stable contact with the table, and a set of points on the object surface for the end-effectors (EEFs) of a dual-arm manipulator to stably grasp the object. Object manipulation can be realized by solving a graph, considering the kinematic constraints of pivoting and tumbling. For pivoting, we consider two supporting styles: stable support (SP) and unstable support (USP). Our proposed method manipulates large and heavy objects by selectively using the two different support styles of pivoting and tumbling according to the conditions on the table area. In addition, it can effectively avoid the limitation arising due to the arm kinematics by regrasping the object. We experimentally demonstrate that a dual-arm manipulator can move an object from the initial to goal position within a limited area on the table, avoiding obstacles placed on the table.

scholarly journals Multiple Depth Maps Integration for 3D Reconstruction Using Geodesic Graph Cuts

2015 ◽  
Vol 25 (03) ◽  
pp. 473-492 ◽  
Author(s):  
Jiangbin Zheng ◽  
Xinxin Zuo ◽  
Jinchang Ren ◽  
Sen Wang
Keyword(s):  
Stereo Vision ◽  
Geodesic Distance ◽  
Graph Cut ◽  
3D Modelling ◽  
Superior Performance ◽  
Object Surface ◽  
Depth Maps ◽  
Depth Images ◽  
Integration Approach ◽  
Suppress Noise

Depth images, in particular depth maps estimated from stereo vision, may have a substantial amount of outliers and result in inaccurate 3D modelling and reconstruction. To address this challenging issue, in this paper, a graph-cut based multiple depth maps integration approach is proposed to obtain smooth and watertight surfaces. First, confidence maps for the depth images are estimated to suppress noise, based on which reliable patches covering the object surface are determined. These patches are then exploited to estimate the path weight for 3D geodesic distance computation, where an adaptive regional term is introduced to deal with the "shorter-cuts" problem caused by the effect of the minimal surface bias. Finally, the adaptive regional term and the boundary term constructed using patches are combined in the graph-cut framework for more accurate and smoother 3D modelling. We demonstrate the superior performance of our algorithm on the well-known Middlebury multi-view database and additionally on real-world multiple depth images captured by Kinect. The experimental results have shown that our method is able to preserve the object protrusions and details while maintaining surface smoothness.

Cognitive gadgets and cognitive priors

2019 ◽  
Vol 42 ◽  
Author(s):  
Gian Domenico Iannetti ◽  
Giorgio Vallortigara
Keyword(s):  
Cognitive Neuroscience ◽  
Selection Of

Abstract Some of the foundations of Heyes’ radical reasoning seem to be based on a fractional selection of available evidence. Using an ethological perspective, we argue against Heyes’ rapid dismissal of innate cognitive instincts. Heyes’ use of fMRI studies of literacy to claim that culture assembles pieces of mental technology seems an example of incorrect reverse inferences and overlap theories pervasive in cognitive neuroscience.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

Measurements of the Cape Astrometric Survey of the Southern Hemisphere

1978 ◽  
Vol 48 ◽  
pp. 515-521
Author(s):  
W. Nicholson
Keyword(s):  
Southern Hemisphere ◽  
Automatic Measuring ◽  
Measuring Machine ◽  
Final Selection ◽  
Selection Of

SummaryA routine has been developed for the processing of the 5820 plates of the survey. The plates are measured on the automatic measuring machine, GALAXY, and the measures are subsequently processed by computer, to edit and then refer them to the SAO catalogue. A start has been made on measuring the plates, but the final selection of stars to be made is still a matter for discussion.

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