On the Galloway-Type of Spatial Mechanisms

1990 ◽  
Vol 112 (4) ◽  
pp. 466-471
Author(s):  
J. Rastegar
Keyword(s):  
Geometric Parameters ◽  
Equal Length ◽  
Output Link ◽  
Spatial Mechanism ◽  
Numerical Example ◽  
Link Type ◽  
Spatial Mechanisms ◽  
Drag Link

The Galloway mechanism is a plane four-bar, drag-link-type linkage with one pair of equal-length shorter links, and one pair of equal-length longer links, forming a rhomboid geometry. The short links constitute the frame and the input links. In a Galloway mechanism, two full rotations of the input link result in a single rotation of the output link. In this paper, the Galloway mechanism is analyzed and the rules governing its motion are found. The conditions necessary for the existence of a Galloway-type spatial mechanism are then determined. As an example, the necessary relationships between the geometric parameters of a spatial RRRSR mechanism are derived. A numerical example is included.

Approximated Grashof-Type Movability Conditions for RSSR Mechanisms With Force Transmission Limitations

1992 ◽  
Vol 114 (1) ◽  
pp. 74-81 ◽  
Author(s):  
J. Rastegar ◽  
Q. Tu
Keyword(s):  
Closed Form ◽  
Closed Loop ◽  
Open Loop ◽  
Approximation Technique ◽  
Force Transmission ◽  
Output Link ◽  
Link Type ◽  
Spatial Mechanisms ◽  
Loop Chain ◽  
Drag Link

Closed-form Grashof-type movability conditions are derived for closed-loop RSSR mechanisms using a geometrical approximation technique. The conditions that ensure the presence of crank-rocker and drag-link type mechanisms are derived with and without force transmission limitations. The force transmission limitations may be specified as a function of the output link angle. The accuracy of the approximated conditions is analyzed. As an example, the conditions are used to synthesize a function generating mechanism with fully rotatable crank and with various force transmission requirements. The developed technique is general, and can be applied to other similar spatial mechanisms. The application of this approach to geometrical synthesis of open-loop chain manipulators is discussed.

On the Derivation of Grashof-Type Moveability Conditions With Transmission Angle Control for Spatial Mechanisms

1987 ◽  
Author(s):  
J. Rastegar
Keyword(s):  
Approximation Techniques ◽  
Link Type ◽  
Revolute Joints ◽  
Spatial Mechanisms ◽  
Transmission Angle ◽  
Full Rotation ◽  
Drag Link

Abstract Derivation of Grashof-type conditions for spatial mechanisms that may include transmission angle limitations are discussed. It is shown that in general, different conditions need to be derived for each one of the existing configurations of the mechanism. In the absence of any transmission angle control, the conditions would be identical for pairs of configurations. As an example, for RRRSR mechanisms, Grashof-type conditions that ensure crank rotatability, the existence of a drag link type of mechanism, single or multiple changeover points, the possibility of full rotation at intermediate revolute joints, etc., are determined. A general discussion of the problems involved in such derivations, the use of approximation techniques to overcome some of the problems, and several other related subjects are presented.

On the Derivation of Grashof-Type Movability Conditions With Transmission Angle Limitations for Spatial Mechanisms

1989 ◽  
Vol 111 (4) ◽  
pp. 519-523 ◽  
Author(s):  
J. Rastegar
Keyword(s):  
Approximation Techniques ◽  
Link Type ◽  
Revolute Joints ◽  
Spatial Mechanisms ◽  
Transmission Angle ◽  
Full Rotation ◽  
Drag Link

Derivation of Grashof-type movability conditions for spatial mechanisms that may include transmission angle limitations is discussed. It is shown that in general, different conditions must be derived for each configuration (branch) of a mechanism. In the absence of transmission angle limitations, the conditions become identical for pairs of configurations. As an example, Grashof-type conditions that ensure crank rotatability, existence of drag link type of mechanisms, the presence of single or multiple changeover points, and the possibility of full rotation at intermediate revolute joints are derived for a spatial RRRSR mechanism. The problems involved in such derivations, the use of approximation techniques, and a number of related subjects are discussed.

On the shaft locations of two contra-rotating counterweights for balancing spatial mechanisms

1997 ◽  
Vol 211 (8) ◽  
pp. 567-578 ◽  
Author(s):  
S-T Chiou ◽  
J-C Tzou
Keyword(s):  
Root Mean Square ◽  
Mean Square ◽  
Spatial Mechanism ◽  
Spatial Mechanisms ◽  
Crank Mechanism ◽  
Frequency Term ◽  
Shaking Moment

It has been shown in a previous work that a frequency term of the shaking force of spatial mechanisms, whose hodograph is proved to be an ellipse, can be eliminated by a pair of contrarotating counterweights. In this work, it is found that the relevant frequency term of the shaking moment is minimized if the balancing shafts are coaxial at the centre of a family of ellipsoids, called isomomental ellipsoids, with respect to (w.r.t.) any point on an ellipsoid, as is also the root mean square (r.m.s.) of the relevant frequency term of the shaking moment. It can also be minimized even though the location of either shaft, but not both, is chosen arbitrarily on a plane. The location of the second shaft is then determinate. In order to locate the centre, a derivation for the theory of isomomental ellipsoids of a frequency term of the shaking moment of spatial mechanisms is given. It is shown that the r.m.s. of a frequency term shaking moment of a spatial mechanism w.r.t. the concentric centre of the isomomental ellipsoids is the minimum. Examples of a seven-link 7-R spatial linkage and a spatial slider-crank mechanism are included.

Closed-Form Displacement Relations of a Five-Link R-R-C-C-R Spatial Mechanism

1971 ◽  
Vol 93 (1) ◽  
pp. 221-226 ◽  
Author(s):  
A. H. Soni ◽  
P. R. Pamidi
Keyword(s):  
Closed Form ◽  
Polynomial Equation ◽  
Input Output ◽  
Degree Polynomial ◽  
Spatial Mechanism ◽  
Dual Number ◽  
Numerical Example

Using (3 × 3) matrices with dual-number elements, closed form displacement relationships are derived for a spatial five-link R-R-C-C-R mechanism. The input-output closed form displacement relationship is an eighth degree polynomial equation. A numerical example is presented.

Kinematic Analysis of Spatial Mechanisms by Means of Screw Coordinates. Part 2—Analysis of Spatial Mechanisms

1971 ◽  
Vol 93 (1) ◽  
pp. 67-73 ◽  
Author(s):  
M. S. C. Yuan ◽  
F. Freudenstein ◽  
L. S. Woo
Keyword(s):  
Computer Program ◽  
Kinematic Analysis ◽  
Static Force ◽  
Single Degree Of Freedom ◽  
Numerical Examples ◽  
Spatial Mechanism ◽  
Single Degree ◽  
Spatial Mechanisms ◽  
Torque Analysis ◽  
Basic Concepts

The basic concepts of screw coordinates described in Part I are applied to the numerical kinematic analysis of spatial mechanisms. The techniques are illustrated with reference to the displacement, velocity, and static-force-and-torque analysis of a general, single-degree-of-freedom spatial mechanism: a seven-link mechanism with screw pairs (H)7. By specialization the associated computer program is capable of analyzing many other single-loop spatial mechanisms. Numerical examples illustrate the results.

Integrated Kinematic and Dynamic Optimal Synthesis of Spatial Mechanisms

1987 ◽  
Author(s):  
A. J. Kakatsios ◽  
S. J. Tricamo
Keyword(s):  
Nonlinear Programming ◽  
Simultaneous Optimization ◽  
Programming Formulation ◽  
Joint Torques ◽  
Spatial Mechanism ◽  
Spatial Mechanisms ◽  
Structural Error ◽  
Integrated Technique ◽  
Driving Torque ◽  
Shaking Moment

Abstract A novel integrated technique permitting the simultaneous optimization of kinematic and dynamic characteristics in the synthesis of spatial mechanisms is shown. The nonlinear programming formulation determines mechanism variables which simultaneously minimize the maximum values of bearing reactions, joint torques, driving torque, shaking moment, and shaking force while constraining the maximum kinematic structural error to a prescribed bound. The method is applied to the design of a path generating RRSS spatial mechanism with prescribed input link timing. Dynamic reactions in the mechanisms synthesized using the integrated technique were substantially reduced when compared to those of a mechanism synthesized to satisfy only the specified kinematic conditions.

A PHIGS-Based Graphics Input Interface for Spatial Mechanism Design

1987 ◽  
Author(s):  
B. R. Thatch ◽  
A. Myklebust
Keyword(s):  
Data Entry ◽  
Interactive Graphics ◽  
Mechanism Synthesis ◽  
Spatial Mechanism ◽  
Input Interface ◽  
New Methods ◽  
Spatial Mechanisms ◽  
Six Dof ◽  
Device Independence ◽  
Definition Of

Abstract Creation of input specifications for synthesis or analysis of spatial mechanisms can be a significant problem. A graphics preprocessor which interactively assists in the definition of spatial mechanism problems is described. New methods of depth cucing and six DOF data entry are presented. To achieve graphics device-independence, the proposed graphics standard PHIGS (Programmer’s Hierarchical Interactive Graphics System) is used. Examples of application are presented including generation of input commands for Integrated Mechanisms Program (IMP) and generation of input for spatial mechanism synthesis routines.

Analytical Criteria for the Analysis of Design Propagations in Mechanisms

1996 ◽  
Author(s):  
Hong-Liu Zou ◽  
Karim Abdel-Malek ◽  
Jia-Yi Wang
Keyword(s):  
Graph Theory ◽  
Design Variable ◽  
Jacobian Matrix ◽  
Suspension System ◽  
Joint Position ◽  
Closed Loops ◽  
Numerical Example ◽  
Cartesian Space ◽  
Spatial Mechanisms ◽  
Joint Coordinates

Abstract A broadly applicable formulation for investigating design propagations in mechanisms is developed and illustrated. Analytical criteria in terms of the variations of joint position vectors and orientation matrices for planar and spatial mechanisms are presented. Mechanisms are represented using graph theory and closed loops are converted to a tree-like structure by cutting joints and introducing new constraints. The Jacobian matrix in Cartesian space is then transformed to Joint coordinates space. Two cases are considered: a pair of bodies remain connected by one joint after cutting additional joints and a pair of bodies are disconnected after cutting joints. Using this method, a designer has the ability to study the propagated effect of changing a design variable on the design. The presented formulation is validated through a numerical example of a McPherson strut suspension system. The system is analyzed and an assembled configuration is computed after a change in design.

scholarly journals On the Design of An Innovative Latch Mechanism in SMIFed Wafer Containers

2003 ◽  
Vol 19 (3) ◽  
pp. 389-395
Author(s):  
Wei-Ming Pai ◽  
Dar-Zen Chen ◽  
Jyh-Jone Lee ◽  
Chi-Zer Ho
Keyword(s):  
Kinetic Energy ◽  
Integrated Circuits ◽  
Design Process ◽  
Computer Simulations ◽  
Optimization Problem ◽  
Output Link ◽  
Numerical Example ◽  
Second Stage ◽  
Transmission Angle ◽  
Two Stages

AbstractThis paper presents the design process for an innovative latch mechanism in a standard mechanical interfaced (SMIFed) wafer container, in which the manufactured integrated circuits are stored. An innovative latch mechanism is proposed and applied to the wafer container, such that the container door can be latched and air-tightly sealed during storage or transportation. The design process is divided into two stages. In the first stage, an output slot-cam is designed in order to generate decoupled fine motions of the output link. The issue is formulated as an optimization problem where the output link dimensions are optimized to minimize the resultant pin forces subject to an adequate transmission angle. In the second stage, the input slot-cam is designed to achieve that kinetic energy of the elastic gasket on the container lid is absorbed at a uniform rate. Finally, a numerical example and computer simulations are given to demonstrate the results of design process. It is believed that this work could aid in enhancing the performance and reliability of the latch mechanism in the SMIF environment.

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