scholarly journals Kinematic Analysis of Spatial Geared Mechanisms

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Julie Penaud ◽  
Daniel Alazard ◽  
Alexandre Amiez
Keyword(s):  
Adjacency Matrix ◽  
Kinematic Analysis ◽  
Polar Coordinates ◽  
Constraint Matrix ◽  
New Approach ◽  
Bevel Gears ◽  
Gear Trains ◽  
Complex Coefficients ◽  
Two Degree Of Freedom ◽  
General Method

In this paper, a general method for kinematic analysis of complex gear mechanisms, including bevel gear trains and noncollinear input and output axes, is presented. This new approach is based on the nullspace of the kinematic constraint matrix computed from the mechanism graph or its adjacency matrix. The novelty is that the elements of the adjacency matrix are weighted with complex coefficients allowing bevel gears to be taken into account and the angular velocity of each link to be directly expressed using polar coordinates. This approach is illustrated on a two-degree-of-freedom car differential and applied to a helicopter main gear box. A MATLAB open source software was developed to implement this method.

A Framework for Efficiency Evaluation of Multi-Degree-of-Freedom Gear Trains

1996 ◽  
Vol 118 (4) ◽  
pp. 556-560 ◽  
Author(s):  
C. Innocenti
Keyword(s):  
Experimental Data ◽  
Finite Number ◽  
Degree Of Freedom ◽  
Gear Train ◽  
Efficiency Evaluation ◽  
Suggested Approach ◽  
New Approach ◽  
Gear Trains ◽  
Two Degree Of Freedom

The paper proposes a new approach to the efficiency evaluation of any one- or multi-degree-of-freedom gear trains. The suggested approach generalizes the known procedures developed for two-degree-of-freedom gear trains. It is based on the determination of a vector whose components are the torques delivered to the shafts of the gear train. Furthermore the paper shows that, for a notable category of gear trains, such a vector can have only a finite number of directions, which implies that a limited number of experimental data suffices for estimating the efficiency at any operational condition. Examples of application of the proposed methodology are provided.

scholarly journals Kinematic Precision of Gear Trains

1983 ◽  
Vol 105 (3) ◽  
pp. 317-326 ◽  
Author(s):  
F. L. Litvin ◽  
R. N. Goldrich ◽  
J. J. Coy ◽  
E. V. Zaretsky
Keyword(s):  
Gear Tooth ◽  
Contact Point ◽  
Approximate Methods ◽  
Gear Noise ◽  
Bevel Gears ◽  
Tooth Surfaces ◽  
Noise Measurements ◽  
Gear Trains ◽  
Helicopter Transmission ◽  
General Method

Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. This paper explains a general method for the determination of kinematic precision of gear trains. The general method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general and approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular-arc (Wildhaber-Novikov) gears, and spiral-bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.

The Design of a Chain of Spherical Stephenson Mechanisms for a Gearless Robotic Pitch-Roll Wrist

2005 ◽  
Vol 128 (2) ◽  
pp. 422-429 ◽  
Author(s):  
S. Hernandez ◽  
S. Bai ◽  
J. Angeles
Keyword(s):  
Unmodeled Dynamics ◽  
Manufacturing Cost ◽  
Interference Avoidance ◽  
Dimensional Synthesis ◽  
Bevel Gears ◽  
Industrial Manipulators ◽  
Differential Mechanism ◽  
Gear Trains ◽  
Robot Performance ◽  
A Chain

Although bevel-gear robotic wrists are widely used in industrial manipulators due to their simple kinematics and low manufacturing cost, their gear trains function under rolling and sliding, the latter bringing about noise and vibration. Sliding is inherent to the straight teeth of the bevel gears of these trains. Moreover, unavoidable backlash introduces unmodeled dynamics, which mars robot performance. To alleviate these drawbacks, a gearless pitch-roll wrist is currently under development for low backlash and high stiffness. The wrist consists of spherical cam-rollers and spherical Stephenson linkages, besides two roller-carrying disks that drive a combination of cams and Stephenson mechanisms, the whole system rotating as a differential mechanism. The paper focuses on the design of the chain of spherical Stephenson mechanisms. The problem of the dimensional synthesis is addressed, and interference avoidance is discussed. An embodiment of the concept is also included.

Meshing Efficiency Analysis of Two Degree-of-Freedom Epicyclic Gear Trains

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Essam Lauibi Esmail
Keyword(s):  
Reference Frame ◽  
Power Efficiency ◽  
Power Flow ◽  
Flow Direction ◽  
Efficiency Analysis ◽  
Degree Of Freedom ◽  
Gear Train ◽  
Epicyclic Gear ◽  
Gear Trains ◽  
Two Degree Of Freedom

The concept of potential power efficiency is introduced as the efficiency of an epicyclic gear train (EGT) measured in any moving reference frame. The conventional efficiency can be computed in a carrier-moving reference frame in which the gear carrier appears relatively fixed. In principle, by attaching the reference frame to an appropriate link, torques can be calculated with respect to each input, output, or (relatively) fixed link in the EGT. Once the power flow direction is obtained from the potential power ratio, the torque ratios are obtained from the potential power efficiencies, the particular expression of the efficiency of the EGT is found in a simple manner. A systematic methodology for the efficiency analysis of one and two degree-of-freedom (DOF) EGTs is described, and 14 ready-to-use efficiency formulas are derived for 2DOF gear pair entities (GPEs). This paper includes also a discussion on the redundancy of the efficiency formulas used for 1DOF GPEs. An incomplete in the efficiency formulas in previous literature, which make them susceptible to wrong application, is brought to light.

A Generalized Approach for the Kinematic Analysis of Planar Mechanisms

1995 ◽  
Vol 209 (4) ◽  
pp. 237-244
Author(s):  
D J A Simpson ◽  
J E L Simmons ◽  
G Moldovean
Keyword(s):  
Computer Program ◽  
Analytical Method ◽  
Building Block ◽  
Kinematic Analysis ◽  
Displacement Velocity ◽  
Planar Mechanisms ◽  
New Approach ◽  
Wide Range ◽  
Complex Mechanisms

This paper describes a new approach to the kinematic analysis of planar mechanisms. The basis of the analytical method is a generic four-bar sub-mechanism which is used as the single building block from which other composite mechanisms may be created. A computer program has been written embodying this method and has been demonstrated to operate successfully providing animated displays of displacement, velocity and acceleration diagrams for a wide range of complex mechanisms.

A new approach to the kinematic analysis of universal joints

2010 ◽  
Vol 52 (5) ◽  
pp. 332-337
Author(s):  
Gültekin Karadere ◽  
Osman Kopmaz ◽  
Emin Güllü
Keyword(s):  
Kinematic Analysis ◽  
New Approach ◽  
Universal Joints
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