Algebraic test of relative form closure grasps with its implementation

2014 ◽  
Vol 57 (7) ◽  
pp. 1401-1410 ◽  
Author(s):  
YouLun Xiong ◽  
Tao Xiong ◽  
YuHui Wang
Robotica ◽  
1993 ◽  
Vol 11 (2) ◽  
pp. 185-192 ◽  
Author(s):  
Y. L. Xiong ◽  
D. J. Sanger ◽  
D. R. Kerr

SUMMARYThis paper, as an extension of an earlier paper, presents a geometrical representation and theoretical foundation of robot grasping that is affected by friction and by the magnitudes of normal contact forces. Grasp analysis and synthesis are based on the concepts of constraint cone (region), restraint cone and freedom cone in the force screw-space and location screw-space. In fact, the freedom cone is the aggregate of all the screws repelling and reciprocal to the grasp geometry (denoted by the restraint cone). Moreover, the constraint cone and the constraint region describe the effect of friction and the influence of the amplitudes of normal forces. The conditions of equilibrium grasp, stable grasp, form closure, force closure, and relative form closure are derived from the geometrical representation, and approaches are suggested for the design of adaptable fixtures, and for automatic grasp planning. It is shown that relative form closure is of great significance for frictional grasp, since it is possible to generate enough internal forces in the subspace spanned by the contacts and consequently produce corresponding friction forces in the reciprocal subspace.


Author(s):  
Felix R. FitzRoy ◽  
Michael A. Nolan

AbstractThe importance of both income rank and relative income, as indicators of status, has long been recognised in the literature on life satisfaction and happiness. Recently, several authors have made explicit comparisons of the relative importance of these two measures of income status, and concluded that rank dominates to the extent that reference income becomes insignificant in regressions including both these explanatory variables, and that even absolute or household income, otherwise always positively related to happiness, may lose statistical significance. Here we test this hypothesis with a large UK panel (British Household Panel Survey and Understanding Society) for 1996–2017, split by age and retirement status, and find, contrary to previous results, that rank, household income and reference income are all usually important explanatory variables, but with significant differences between subgroups. This finding holds when rank is in its often-used relative form, and also with absolute rank.


2021 ◽  
Vol 52 (4) ◽  
pp. 367-378
Author(s):  
S. Wurzbacher ◽  
S. Gach ◽  
U. Reisgen ◽  
C. Hopmann
Keyword(s):  

Author(s):  
Pankaj Sharma ◽  
Anupam Saxena ◽  
Ashish Dutta

The study of multi-agent capture and manipulation of an object has been an area of active interest for many researchers. This paper presents a novel approach using Genetic Algorithm to determine the optimal contact points and the total number of agents (mobile robots) required to capture a stationary generic 2D polygonal object. After the goal points are determined the agents then reach their respective goals using a decentralized projective path planning algorithm. Form closure of the object is obtained using the concept of accessibility angle. The object boundary is first expanded and the robots reach the expanded object goal points and then converge on the actual object. This ensures that the agents reach the actual goal points at the same time and have the correct orientation. Frictionless point contact between the object and robots is assumed. The shape of the robot is considered a circle such that it can only apply force in outward radial direction from its center and along the normal to the object boundary at the contact point. Simulations results are presented that prove the effectiveness of the proposed method.


2014 ◽  
Vol 592-594 ◽  
pp. 1165-1169
Author(s):  
Preeti Gulia ◽  
V.P. Singh

The present work is focused on the graph theory which is used for structural analysis of kinematic chain and identification of degree of freedom. A method based on graph theory is proposed in this paper to solve structural problems by using a suitable example of fourteen links kinematic chain. Purpose of this paper is to give an easy and reliable method for structural analysis of fourteen links kinematic chain. Here, a simple incidence matrix is used to represent the kinematic chain. The proposed method is applied for determining the characteristic polynomial equation of fourteen links kinematic chain. An algebraic test based on graph theory is also used for identifying degree of freedom of kinematic chain whether it is total, partial or fractionated degree of freedom.


Mathematics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 636 ◽  
Author(s):  
Hari Mohan Srivastava ◽  
Bidu Bhusan Jena ◽  
Susanta Kumar Paikray

The concept of the deferred Nörlund equi-statistical convergence was introduced and studied by Srivastava et al. [Rev. Real Acad. Cienc. Exactas Fís. Nat. Ser. A Mat. (RACSAM) 112 (2018), 1487–1501]. In the present paper, we have studied the notion of the deferred Nörlund statistical convergence and the statistical deferred Nörlund summability for sequences of real numbers defined over a Banach space. We have also established a theorem presenting a connection between these two interesting notions. Moreover, based upon our proposed methods, we have proved a new Korovkin-type approximation theorem with algebraic test functions for a sequence of real numbers on a Banach space and demonstrated that our theorem effectively extends and improves most of the earlier existing results (in classical and statistical versions). Finally, we have presented an example involving the generalized Meyer–König and Zeller operators of a real sequence demonstrating that our theorem is a stronger approach than its classical and statistical versions.


Author(s):  
F. Cheraghpour ◽  
M. Dehghani ◽  
A. Feizollahi ◽  
P. Sabetian ◽  
S. Ali A. Moosavian
Keyword(s):  

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