Three-Position Rigid Body Guidance Using Specified Moving Pivots for a Four-Bar Mechanism With Variable Topology

2018 ◽  
Author(s):  
Brian J. Slaboch
Keyword(s):  
Rigid Body ◽  
Algebraic Solution ◽  
Graphical Approach ◽  
Practical Applications ◽  
Joint Geometry ◽  
Topological State ◽  
Variable Topology

This paper provides an algorithm allowing a designer to perform three position rigid body guidance with specified moving pivots for a 4R-RRRP mechanism with variable topology (MVT). A mechanism with variable topology is a mechanism that changes from one topological state to another due to a change in joint geometry. Both a graphical approach and an algebraic solution are presented. An example is provided in which a circuit defect in a 4R mechanism can be avoided using a 4R-RRRP mechanism. Two additional examples are provided that show the results of this new theory. Practical applications for this theory are found in many industries including manufacturing, aerospace, and healthcare.

Novel Classification of Planar Four-Bar Mechanisms With Variable Topology

2018 ◽  
Author(s):  
Brian J. Slaboch ◽  
Bradley W. Hobbs
Keyword(s):  
Medical Devices ◽  
Classification System ◽  
Space Applications ◽  
Practical Applications ◽  
Joint Geometry ◽  
Naming Convention ◽  
Analysis And Synthesis ◽  
Topological State ◽  
Variable Topology

This paper provides a classification system and naming convention for twelve novel types of 4R-RRRP mechanisms with variable topology (MVTs). A mechanism with variable topology is a mechanism that changes from one topological state to another due to a change in joint geometry. An example 4R-RRRP mechanism is provided for each novel mechanism type, along with the appropriate classification and naming convention. The new 4R-RRRP mechanism classes and naming conventions presented in this paper will aid designers in the analysis and synthesis of 4R-RRRP mechanisms. These novel MVTs have practical applications in areas such as manufacturing, space applications, and novel medical devices.

Completely Specified Displacements of a Rigid Body and Their Application in the Direct Kinematics of In-Parallel Mechanisms

1999 ◽  
Vol 121 (4) ◽  
pp. 485-491
Author(s):  
C. Mavroidis
Keyword(s):  
Rigid Body ◽  
The Body ◽  
Algebraic Solution ◽  
Final Position ◽  
Parallel Mechanisms ◽  
Direct Kinematics

In this paper we study the type of completely specified displacements of a rigid body where the distances of six points on the body, between their final and initial positions, have been specified. A method is presented to calculate the screws associated with these displacements. It is shown that there are 24 different screws at the most that will bring the rigid body from the initial to its final position to satisfy the six distances. If the six points are co-planar or symmetrical with respect to a plane then the number of screws reduces to 16. The method to calculate the screws associated with these completely specified displacements, is used to obtain a simple algebraic solution to the direct kinematics problem of a special type of in-parallel mechanisms: the mechanisms where the moving and the fixed platforms are the same.

NON-RIGID BODY INTERPOLATION BASED ON GENERALIZED MORPHOLOGIC MORPHING

2003 ◽  
Vol 03 (02) ◽  
pp. 325-344 ◽  
Author(s):  
WENYU LIU ◽  
HUA LI ◽  
GUANGXI ZHU
Keyword(s):  
Rigid Body ◽  
Computer Animation ◽  
New Technique ◽  
Normal Vector ◽  
Body Rotation ◽  
Rigid Body Rotation ◽  
Practical Applications ◽  
Key Frames ◽  
A New Technique ◽  
Convex Subsets

This paper presents a new technique for non-rigid body interpolation based on generalized morphologic morphing. Non-rigid body interpolation can be divided into non-rigid body metamorphosis and local rigid body rotation. By constructing mappings between the two convex subsets, this approach can solve the metamorphosis problem of two non-homotopic objects. Based on the model of the normal vector sphere for polyhedrons, a fast morphologic summation algorithm for two convex polyhedrons is also proposed; this method avoids much excrescent computation and is faster than most classical implementation. This paper provides the proof of the principle of metamorphosis and discusses the different results of the metamorphosis process for the different objects. It is shown through the experiments that this approach can be applied to automatic font composition and interpolation between two key-frames in 3D computer animation as well as in many other practical applications.

On the Synthesis of Three-Poses Rigid-Body Guidance Mechanisms

2015 ◽  
Author(s):  
Giorgio Figliolini ◽  
Pierluigi Rea
Keyword(s):  
Rigid Body ◽  
Finite Rotation ◽  
Graphical Approach ◽  
Kinematic Characteristics ◽  
Different Types

A graphical approach that is based on the use of the pole triangle among the three poles of the finite rotation, along with its circumcircle and those of the three image pole triangles, which intersect each other at the orthocenter of the pole triangle, is presented in this paper. This method is applied and parameterized in SolidWorks to synthesize different types of mechanisms for any triple of prescribed positions, as four-bar linkages (4R), slider-crank/rocker mechanisms (3RP), double-sliders (2R2P), guiding mechanisms (RPRP). Finally, the kinematic characteristics of the rigid-body guidance mechanisms for three finitely and infinitesimally separated positions are compared via significant examples.

Four-Position Synthesis for Spatial Mechanisms With Two Independent Loops

1992 ◽  
Author(s):  
Chien H. Chiang ◽  
Wei Hua Chieng ◽  
David A. Hoeltzel
Keyword(s):  
Rigid Body ◽  
Mathematical Models ◽  
Analytical Methods ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Practical Applications ◽  
Single Degree ◽  
Spatial Mechanisms ◽  
Position Synthesis ◽  
Independent Loops

Abstract Mathematical models that have been employed to synthesize spatial mechanisms for rigid body guidance have been found to be too complicated to implement in practical applications, especially for four-position guidance synthesis. This paper describes simple analytical methods for synthesizing single degree-of-freedom spatial mechanisms having two independent loops for four precision positions. In addition, prescribed timing has been simultaneously considered for several spatial mechanisms.

Partitioned Transient Analysis Procedures for Coupled-Field Problems: Accuracy Analysis

1980 ◽  
Vol 47 (4) ◽  
pp. 919-926 ◽  
Author(s):  
K. C. Park ◽  
C. A. Felippa
Keyword(s):  
Rigid Body ◽  
Time Integration ◽  
Governing Equations ◽  
Implicit Integration ◽  
Practical Applications ◽  
Coupled Field ◽  
Stable Partition ◽  
Rigid Body Motions ◽  
Coupled Field Problems ◽  
The Right

Partitioned solution procedures for direct time integration of second-order coupled-field systems are studied from the standpoint of accuracy. These procedures are derived by three formulation steps: implicit integration of coupled governing equations, partitioning of resulting algebraic systems and extrapolation on the right-hand partition. It is shown that the combined effect of partition, extrapolation, and computational paths governs the choice of stable extrapolators and preservation of rigid-body motions. Stable extrapolators for various computational paths are derived and implementation-extrapolator combinations which preserve constant-velocity and constant-acceleration rigid-body motions are identified. A spectral analysis shows that the primary error source introduced by a stable partition is frequency distortion. Finally, as a guide to practical applications, the advantages and shortcomings of five specific partitions are discussed.

A Kelvin Theorem and Partial Work of Impulsive Forces

1997 ◽  
Vol 64 (2) ◽  
pp. 438-440 ◽  
Author(s):  
A. P. Ivanov
Keyword(s):  
Rigid Body ◽  
Simple Rule ◽  
Algebraic Solution ◽  
Total Work ◽  
Impulsive Forces ◽  
Independent Work ◽  
Work Done

A rigid body under the action of several impulsive forces is considered. A Kelvin theorem provides a simple rule to calculate the total work done by all impulsive forces, but it is not necessarily applicable to the independent work done by each impulse. It is shown that there exist two cases when the partial work can be determined by the same Kelvin formula. Otherwise, the problem has no algebraic solution.

Non-Hermitian topological light steering

Science ◽  
2019 ◽  
Vol 365 (6458) ◽  
pp. 1163-1166 ◽  
Author(s):  
Han Zhao ◽  
Xingdu Qiao ◽  
Tianwei Wu ◽  
Bikashkali Midya ◽  
Stefano Longhi ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Topological Insulators ◽  
Dynamic Control ◽  
High Density ◽  
Light Transport ◽  
Practical Applications ◽  
Data Capacity ◽  
Topological States ◽  
Topological State ◽  
Robust Transmission

Photonic topological insulators provide a route for disorder-immune light transport, which holds promise for practical applications. Flexible reconfiguration of topological light pathways can enable high-density photonics routing, thus sustaining the growing demand for data capacity. By strategically interfacing non-Hermitian and topological physics, we demonstrate arbitrary, robust light steering in reconfigurable non-Hermitian junctions, in which chiral topological states can propagate at an interface of the gain and loss domains. Our non-Hermitian–controlled topological state can enable the dynamic control of robust transmission links of light inside the bulk, fully using the entire footprint of a photonic topological insulator.

scholarly journals Profile Synthesis of Prismatic-Prismatic Variable Joints for Use in Reconfigurable Mechanisms

2018 ◽  
Author(s):  
Ryan D. Callahan ◽  
Philip A. Voglewede
Keyword(s):  
Machine Design ◽  
Practical Implementation ◽  
Type Ii ◽  
Design Constraints ◽  
Joint Geometry ◽  
Reconfigurable Mechanisms ◽  
Topology Changes ◽  
Variable Topology ◽  
Motion Profile ◽  
Space Approach

Reconfigurable mechanisms provide increased flexibility in machine design and can be used in a variety of applications. Variable joints in reconfigurable mechanisms allow for machine designs that better optimize space and resources. This paper synthesizes the motion profiles of prismatic-prismatic higher variable joints based upon the configuration space approach. Variable joints enable the creation of Type II Mechanisms with Variable Topology, mechanisms whose topology changes due to changes in joint geometry. The goal of this synthesis is to be able to analyze the motion profile, allowing to understand the design constraints of these joints as well as outline the design for the practical implementation of these joints.

On the Operation Space and Motion Compatibility of Variable Topology Mechanisms

2011 ◽  
Vol 3 (2) ◽  
Author(s):  
Win-Bin Shieh ◽  
Frederick Sun ◽  
Dar-Zen Chen
Keyword(s):  
Kinematic Chains ◽  
Joint Geometry ◽  
Interface System ◽  
Mechanical Interface ◽  
Variable Topology

With the implementation of just one mechanism, variable topology mechanisms can serve the functions of many mechanisms by changing their topology. These types of mechanisms have raised interest and attracted numerous studies in recent years, yet few of these studies have focused discussing of these mechanisms in light of their operation space. As the change of a variable topology mechanism is induced by either intrinsic constraints or constraints due to the change of joint geometry profile, the operation space of kinematic joints and kinematic chains in various working stages is changed in accordance. A theoretic framework based on the concept of the operation space of variable topology mechanisms is presented here. A number of characteristics with regard to the motion compatibility among joints and loops in different working stages are derived, laying a foundation for systematical synthesis of variable topology mechanisms. Design of a novel latch mechanism for the standardized mechanical interface system is given as an illustrative example for the synthesis of a variable topology mechanism.

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