Stereoscopic Drawings Made by Analog Computer of Three-Dimensional Surfaces Generated by Spatial Mechanism

1971 ◽  
Vol 93 (1) ◽  
pp. 239-250
Author(s):  
L. E. Torfason ◽  
F. R. E. Crossley
Keyword(s):  
Three Dimensional ◽  
Analog Computer ◽  
Ball Joint ◽  
Spatial Mechanism ◽  
Transmission Properties ◽  
Spatial Mechanisms ◽  
As If

Spatial mechanisms with up to five links and containing at least one ball joint can be solved by considering the intersection of the three dimensional surfaces which can be generated by portions of the mechanism. This paper presents a method whereby stereoscopic pairs of the surfaces can be drawn using an electronic analog computer and the figures viewed as if they were three dimensional. This results in a far better visualization of the surfaces. In many cases it can be seen what the type of intersection between surfaces is. This determines the gross motion of the mechanism, the limits of its motion, and an estimate of its transmission properties.

The Intersections of Solids Shown by Electronic Analog for Mechanism Simulation

1971 ◽  
Vol 93 (1) ◽  
pp. 17-26 ◽  
Author(s):  
L. E. Torfason ◽  
F. R. E. Crossley
Keyword(s):  
Three Dimensional ◽  
Analog Computer ◽  
Spatial Mechanisms

The motion of certain spatial mechanisms with up to five links and containing at least one ball-and-socket joint can be visualized and analyzed by considering the intersections of three-dimensional surfaces generated by the mechanism. In this paper these solids and their intersections are represented by electronic analog computer, which can fully simulate in this way the motion capabilities of each link of the mechanism, and plot their relative displacements.

The Study of Spatial Mechanisms by Electronic Analog Computer

1966 ◽  
Vol 88 (3) ◽  
pp. 301-310
Author(s):  
R. E. Keller
Keyword(s):  
Feedback Control ◽  
Control Systems ◽  
Analog Computer ◽  
Simulation Technique ◽  
Spatial Mechanism ◽  
Spatial Mechanisms ◽  
Feedback Control Systems ◽  
Geometrical Relationships

A simulation technique, applicable to any spatial mechanism having lower pairs, is presented. A detailed description of the required electronic analog-computer circuitry is given. The geometrical relationships imposed by a mechanism are satisfied in the simulation by contactor feedback-control systems, thereby minimizing the need for nonlinear computing components such as squarers and multipliers. Several example simulations are presented.

Parameterization of Three-Dimensional Rigid Body Guidance Incorporating Planar Gear Connections in a Spatial Closed-Loop Mechanism With Parallel Consecutive Axes

2008 ◽  
Author(s):  
Javier Rolda´n Mckinley ◽  
Carl Crane ◽  
David B. Dooner
Keyword(s):  
Computer Animation ◽  
Closed Loop ◽  
Three Dimensional ◽  
Motion Generation ◽  
Repetitive Motion ◽  
End Effector ◽  
Spatial Mechanism ◽  
Joint Axis ◽  
Position And Orientation ◽  
Six Degree Of Freedom

This paper introduces a reconfigurable closed-loop spatial mechanism that can be applied to repetitive motion tasks. The concept is to incorporate five pairs of non-circular gears into a six degree-of–freedom closed-loop spatial chain. The gear pairs are designed based on given mechanism parameters and a user defined motion specification of a coupler link of the mechanism. It is shown in the paper that planar gear pairs can be used if the spatial closed-loop chain is comprised of six pairs of parallel joint axes, i.e. the first joint axis is parallel to the second, the third is parallel to the fourth, ..., and the eleventh is parallel to the twelfth. This paper presents the synthesis of the gear pairs that satisfy a specified three-dimensional position and orientation need. Numerical approximations were used in the synthesis the non-circular gear pairs by introducing an auxiliary monotonic parameter associated to each end-effector position to parameterize the motion needs. The findings are supported by a computer animation. No previous known literature incorporates planar non-circular gears to fulfill spatial motion generation needs.

scholarly journals Polarization and Transmission Properties of Metamaterial-Based Three-Dimensional Plasmonic Structure

2011 ◽  
Vol 3 (3) ◽  
pp. 400-406 ◽  
Author(s):  
Hengyi Li ◽  
Xiangang Luo ◽  
Lianshan Yan ◽  
Kunhua Wen ◽  
Zhen Guo ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Transmission Properties ◽  
Plasmonic Structure

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.

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.

Synthesis and analysis of spatial CS-3SS mechanism for body guidance

2015 ◽  
Vol 229 (13) ◽  
pp. 2455-2466
Author(s):  
Wen-Yeuan Chung
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Kinematic Chain ◽  
Spherical Joint ◽  
Numerical Examples ◽  
Spatial Mechanism ◽  
Cylindrical Joint ◽  
Input Parameters ◽  
Three Stages ◽  
Moving Platform

This work presents a new spatial mechanism for three-dimensional body guidance. The moving platform of this mechanism is supported by a C–S leg and three S–S legs. Driving unit is the cylindrical joint and has two input parameters. The strategy for synthesizing the C–S leg is proposed and at most eight positions of the spherical joint can be prescribed, while at most seven positions can be prescribed in designing each S–S leg. This CS-3SS mechanism can thus be synthesized by prescribing at most seven precision poses. For this multi-loop spatial mechanism, both noticeable works that are the analysis of configurations and strategy for evaluating branch defects are carried out. The mechanism by giving two inputs has zero degrees of freedom and is analogous to a spherical kinematic chain with five links. At most eight configurations can be obtained and the criterion of double configurations is derived successfully. These results are based on to develop the strategy for evaluating branch defects. This strategy has three stages which are calculating the values of criteria, checking properties of other branches and final verification. Two numerical examples are presented to illustrate the design, the evaluation of defects, and the performance of the proposed mechanism.

Solution of Topology Embryonic Graph and Topology Graph for Unified Planar-Spatial Mechanisms

2003 ◽  
Author(s):  
Lu Yi ◽  
Tatu Leinonen
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Matrix Approach ◽  
Group Approach ◽  
Spatial Mechanism ◽  
Spatial Mechanisms ◽  
And Topology ◽  
Topology Graph ◽  
Relative Theory

An analysis matrix approach for solving an isomeric topology embryonic graph and a digital group approach for solving an isomeric topology graph of a unified planar-spatial mechanism are presented and the relative theory is discussed. Firstly, all binary links are removed from each acceptable linkage system with different degrees of freedom, many analysis matrixes are constructed, and many topology embryonic graphs of the mechanism are derived. Secondly, from an acceptable multi-element link combination of planar or spatial mechanisms, a rule for determining the isomeric topology embryonic graphs and an unreasonable topology embryonic graph is obtained. Thirdly, by considering the degree of freedom of the mechanism and the configuration of a planar or spatial mechanism, the number of binary links is determined. Finally, all removed binary links are rearranged systematically back into an isomeric topology embryonic graph, and the acceptable topology graphs of the mechanism are derived by using a digital group approach. Some illustrations show that the two approaches are simple and effective tools and can be employed to synthesize both planar and spatial mechanisms.

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