Characteristic Surfaces for Three-Position Motion Generation With Planar Four-Bar Mechanisms

1987 ◽  
Vol 109 (2) ◽  
pp. 183-188
Author(s):  
C. R. Barker ◽  
J. Baumann
Keyword(s):  
Solution Space ◽  
Final Solution ◽  
Motion Generation ◽  
Numerical Example ◽  
All Solutions ◽  
Cartesian Plane ◽  
The Relationship ◽  
Generation Problem

This paper considers the relationship between the three-position motion generation problem and the solution space for planar four-bar mechanisms. After one half of the basic four bar had been selected, two infinities of solutions still remained. These solutions are mapped in a plane to determine where the particular types of mechanisms occur. A contour is then generated in the mapping plane which joins together all solutions which share a common characteristic in regard to their link lengths. This same contour can be displayed in the solution space and in the Cartesian plane in which the motion generation is defined. Significant useful information to assist in selecting the final solution is obtained. A numerical example is used for illustration, but the results can be applied to any three-position motion generation problem.

Characteristic Surfaces for Three-Position Function Generation With Planar Four-Bar Mechanisms

1989 ◽  
Vol 111 (1) ◽  
pp. 104-109 ◽  
Author(s):  
C. R. Barker ◽  
P.-L. Tso
Keyword(s):  
Design Problem ◽  
Solution Space ◽  
Function Generation ◽  
Numerical Example ◽  
All Solutions ◽  
The Relationship ◽  
Generation Problem

This paper considers the relationship between the three-position function-generation problem and the solution space for planar four-bar mechanisms. The two infinities of solutions possible are mapped in a plane to determine the locations where particular types of mechanisms occur. It is possible to generate a contour in the mapping plane which joins together all solutions which possess a common characteristic in regard to their link lengths. This same contour can be displayed in the solution space to ascertain the overall characteristics of potential solutions to the design problem. A numerical example is used for illustrative purposes, but the results can be applied to any three-position function-generation problem.

Characteristic Surfaces for Three Position Function Generation With Planar Four Bar Mechanisms

1987 ◽  
Author(s):  
C. R. Barker ◽  
P.-L. Tso
Keyword(s):  
Design Problem ◽  
Solution Space ◽  
Function Generation ◽  
Numerical Example ◽  
All Solutions ◽  
The Relationship ◽  
Generation Problem

Abstract This paper considers the relationship between the three position function generation problem and the solution space for planar four bar mechanisms. The two infinities of solutions possible are mapped in a plane to determine the locations where particular types of mechanisms occur. It is possible to generate a contour in the mapping plane which joins together all solutions which possess a common characteristic in regard to their link lengths. This same contour can be displayed in the solution space to ascertain the overall characteristics of potential solutions to the design problem. A numerical example is used for illustrative purposes, but the results can be applied to any three position function generation problem.

A Novel Synthesis Method for Three-Position Motion Generation With Planar Four-Bar Mechanisms

2012 ◽  
Author(s):  
Jianyou Han ◽  
Tong Yang
Keyword(s):  
Synthesis Method ◽  
Solution Space ◽  
The Other ◽  
Motion Generation ◽  
Numerical Examples ◽  
Novel Synthesis ◽  
Generation Problem

This paper deals with the three-position motion generation problem with two specific grounded link lengths. There are two infinities of solutions for selecting the two links on the derived contours of the link lengths. These points on the contours are circle points or center points. After one half of the basic four bar had been selected on the contour, two infinities of solutions remained. These solutions can be mapped in a plane to determine where the particular types of mechanisms occur. Furthermore after one half of the basic four bar had been selected on the contour, one infinity of solutions still remained on the other contour. This indicates two infinities of solutions are still remained for the two given link lengths. These contours can be displayed in the solution space in which the motion generation is defined. With these significant useful information the better mechanism can be obtained, which satisfies more design conditions. Expressions of the contours are derived. Two numerical examples are used for illustration, but the results can be applied to any three-position motion generation problem.

scholarly journals Mass and spin for classical strings in dS3

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Klaas Parmentier
Keyword(s):  
Black Hole ◽  
Evolution Equation ◽  
Cosmic Strings ◽  
Center Of Mass ◽  
Open String ◽  
Conserved Quantities ◽  
Numerical Example ◽  
All Solutions

Abstract We demonstrate that all rigidly rotating strings with center of mass at the origin of the dS3 static patch satisfy the Higuchi bound. This extends the observation of Noumi et al. for the open GKP-like string to all solutions of the Larsen-Sanchez class. We argue that strings violating the bound end up expanding towards the horizon and provide a numerical example. Adding point masses to the open string only increases the mass/spin ratio. For segmented strings, we write the conserved quantities, invariant under Gubser’s algebraic evolution equation, in terms of discrete lightcone coordinates describing kink collisions. Randomly generated strings are found to have a tendency to escape through the horizon that is mostly determined by their energy. For rapidly rotating segmented strings with mass/spin < 1, the kink collisions eventually become causally disconnected. Finally we consider the scenario of cosmic strings captured by a black hole in dS and find that horizon friction can make the strings longer.

Simulation Optimization of Backrest Mechanism of Separable Bed Chair System

2021 ◽  
Vol 15 ◽  
pp. 1114-1123
Author(s):  
Meng Ning ◽  
Zhi Wu ◽  
Lianjie Chen ◽  
Fan Zhang ◽  
Huitao Chen
Keyword(s):  
Sudden Change ◽  
Optimal Solution ◽  
Simulation Software ◽  
Final Solution ◽  
Integration System ◽  
Modeling And Analysis ◽  
Movement Characteristics ◽  
Fixed Structure ◽  
The Relationship ◽  
Research And Design

Research and design an intelligent bed and chair integration system for assisting inconvenient mobility and aging population. The system consists of a removable detached wheelchair and a c-shaped bed with a fixed structure. The user can switch freely between the mobile wheelchair and the bed to meet the user's requirements of free movement and repositioning.Through the simulation software to analyze the movement characteristics of the bed backboard, the angle of the take-off and landing of the backboard and the sudden change of the take-off and abrupt angular velocity will cause the user to have dizziness and discomfort. In the case of determining the speed of the driving push rod, the relationship between mechanism parameters and installation parameters is the key to affect the lifting rate of the rear plate. Modeling and analysis of each mechanism is performed to determine the relationship between the mechanism parameters and the take-off and landing speed of the backplane. After optimizing the mechanism, the simulation is compared again to obtain the optimal solution. Finally, the optimal solution parameter is the final solution to improve the overall comfort of the nursing bed.

A Generalized Performance Sensitivity Synthesis Methodology for Four-Bar Mechanisms

1992 ◽  
Author(s):  
Ming-Yih Lee ◽  
Arthur G. Erdman ◽  
Salaheddine Faik
Keyword(s):  
Solution Space ◽  
Design Solution ◽  
Link Length ◽  
Performance Sensitivity ◽  
Closed Chain ◽  
Synthesis Methodology ◽  
Position Synthesis ◽  
The Relationship ◽  
Accuracy Performance ◽  
Sensitivity Maps

Abstract A generalized accuracy performance synthesis methodology for planar closed chain mechanisms is proposed. The relationship between the sensitivity to variations of link lengths and the location of the moving pivots of four-link mechanisms is investigated for the particular objective of three and four position synthesis. In the three design positions case, sensitivity maps with isosensitivity curves plotted in the design solution space allow the designer to synthesize a planar mechanism with desired sensitivity value or to optimize sensitivity from a set of acceptable design solutions. In the case of four design positions, segments of the Burmester design curves that exhibit specified sensitivity to link length tolerance are identified. A performance sensitivity criterion is used as a convenient and a useful way of discriminating between many possible solutions to a given synthesis problem.

Global Media and Information Ethics

2011 ◽  
pp. 50-62 ◽  
Author(s):  
D. Ndirangu Wachanga
Keyword(s):  
State Power ◽  
World Order ◽  
Information Ethics ◽  
The State ◽  
Global Information ◽  
Media Ethics ◽  
Global Media ◽  
Optimum Form ◽  
Cartesian Plane ◽  
The Relationship

Any meaningful debate on global media and information ethics is burdened with the complexity of dissecting various disjunctive dynamics that characterize the complexity of emerging global relationships. The authors argue that the emerging global phenomenon problematizes the Cartesian plane of oppositions – center vs. periphery, North vs. South, global vs. local, which has been the forte of globalization studies until recently. It is against this background that the authors seek to examine challenges of having a global information and media ethics. The authors will pay attention to the antagonistic mechanics informing the domination and rejection of intangible ethical principles. In this discussion, they will be guided, partly, by Alleyne’s (2009, p. 384) postulation on the need to pay attention to “changes in state power, the relationship between the market and the state, and modifications in the ideological assumptions about the optimum form of world order.”

scholarly journals On the Geometric Mean Method for Incomplete Pairwise Comparisons

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1873
Author(s):  
Konrad Kułakowski
Keyword(s):  
Least Squares ◽  
Least Squares Method ◽  
Geometric Mean ◽  
Computational Method ◽  
Pairwise Comparisons ◽  
Similar Relationship ◽  
Final Solution ◽  
The Difference ◽  
The Relationship ◽  
Theoretical Considerations

One of the most popular methods of calculating priorities based on the pairwise comparisons matrices (PCM) is the geometric mean method (GMM). It is equivalent to the logarithmic least squares method (LLSM), so some use both names interchangeably, treating it as the same approach. The main difference, however, is in the way the calculations are done. It turns out, however, that a similar relationship holds for incomplete matrices. Based on Harker’s method for the incomplete PCM, and using the same substitution for the missing entries, it is possible to construct the geometric mean solution for the incomplete PCM, which is fully compatible with the existing LLSM for the incomplete PCM. Again, both approaches lead to the same results, but the difference is how the final solution is computed. The aim of this work is to present in a concise form, the computational method behind the geometric mean method (GMM) for an incomplete PCM. The computational method is presented to emphasize the relationship between the original GMM and the proposed solution. Hence, everyone who knows the GMM for a complete PCM should easily understand its proposed extension. Theoretical considerations are accompanied by a numerical example, allowing the reader to follow the calculations step by step.

Elimination of Branch, Grashof, and Order Defects in Path-Angle Generation and Function Generation Synthesis

1979 ◽  
Vol 101 (3) ◽  
pp. 428-437 ◽  
Author(s):  
K. J. Waldron ◽  
E. N. Stevensen
Keyword(s):  
Motion Generation ◽  
Function Generation ◽  
And Function ◽  
Generation Problem

Path-Angle Generation and Function Generation synthesis problems are restated as Plane-Position (or Motion Generation) problems, enabling the use of the classical Burmester technique and recent extensions that permit the avoidance of Branch, Grashof, and Order defects. An example of the solution of a Path-Angle Generation problem is given.

Finite Position Synthesis of 5-SS Platform Linkages Including Partially Specified Joint Locations

2017 ◽  
Author(s):  
Xin Ge ◽  
Anurag Purwar ◽  
Q. J. Ge
Keyword(s):  
Linear Structure ◽  
Motion Generation ◽  
Numerical Examples ◽  
Moving Points ◽  
Unified Algorithm ◽  
Moving Platform ◽  
Position Synthesis ◽  
Partial Specification ◽  
Generation Problem ◽  
Novel Algorithm

A 5-SS platform linkage generates a one-degree-of-freedom motion of a moving platform such that each of five moving points on the platform is constrained on a sphere, or in its degenerated case, on a plane. It has been well established a 5-SS platform linkage can be made to guide though seven positions exactly. This paper investigates the cases when the number of given positions are less than seven that allows for partial specification of locations of the moving points. A recently developed novel algorithm with linear structure in the design equations has been extended for the solution of the problem. The formulation of this expanded motion generation problem unifies the treatment of the input positions and constraints on the moving and fixed joints associated with the 5-SS platform linkage. Numerical examples are provided to show the effectiveness of the unified algorithm.

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