Abstract
In this paper, a dimensional synthesis method for a four-bar (4R) path generator mechanism having revolute joints with clearance is presented. Joint clearances are considered as virtual massless links. The proposed method uses a neural network (NN) to define the characteristics of joints with clearance with respect to the position of the input link, and a genetic algorithm (GA) to implement the optimization of link parameters using an appropriate objective function based on path and transmission angle errors. Training and testing data sets for network weights are obtained from mechanism simulation, and Grashof’s rule is used during the optimization process as constraint. The results show that the proposed method is very efficient for the purpose of modeling the joint variables and also adjusting the link dimensions to optimize planar mechanisms with clearances.
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Abbreviations
- BP:
-
Back propagation
- c :
-
Value with clearance
- d :
-
Desired value
- e :
-
Error
- GA:
-
Genetic algorithm
- G i :
-
Gravity center of the ith mechanism link
- g k :
-
Constraint
- L i :
-
The ith link length
- MLNN:
-
Multi-layered neural network
- NN:
-
Neural network
- P x :
-
x-coordinate value for the path of point P
- P y :
-
y-coordinate value for the path of point P
- r B :
-
Bearing radius
- r j :
-
The jth actual clearance value
- r J :
-
Journal radius
- s :
-
The number of considered points in objective function
- W :
-
Weighting factor in objective function
- w :
-
Network weight
- X :
-
Design variable vector
- x r :
-
Independent design variables
- x min r :
-
Lower bounds of design variables
- x max r :
-
Upper bounds of design variables
- γ j :
-
Angular direction of the jth joint clearance
- μ :
-
Transmission angle
- β :
-
Structural angle
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Erkaya, S., Uzmay, İ. A neural–genetic (NN–GA) approach for optimising mechanisms having joints with clearance. Multibody Syst Dyn 20, 69–83 (2008). https://doi.org/10.1007/s11044-008-9106-6
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DOI: https://doi.org/10.1007/s11044-008-9106-6