An automatic selection of optimal recurrent neural network architecture for processes dynamics modelling purposes

2021 ◽  
pp. 108375
Author(s):  
Krzysztof Laddach ◽  
Rafał Łangowski ◽  
Tomasz A. Rutkowski ◽  
Bartosz Puchalski
Author(s):  
Zhan Li ◽  
Shuai Li

AbstractRedundancy manipulators need favorable redundancy resolution to obtain suitable control actions to guarantee accurate kinematic control. Among numerous kinematic control applications, some specific tasks such as minimally invasive manipulation/surgery require the distal link of a manipulator to translate along such fixed point. Such a point is known as remote center of motion (RCM) to constrain motion planning and kinematic control of manipulators. Recurrent neural network (RNN) which possesses parallel processing ability, is a powerful alternative and has achieved success in conventional redundancy resolution and kinematic control with physical constraints of joint limits. However, up to now, there still is few related works on the RNNs for redundancy resolution and kinematic control of manipulators with RCM constraints considered yet. In this paper, for the first time, an RNN-based approach with a simplified neural network architecture is proposed to solve the redundancy resolution issue with RCM constraints, with a new and general dynamic optimization formulation containing the RCM constraints investigated. Theoretical results analyze and convergence properties of the proposed simplified RNN for redundancy resolution of manipulators with RCM constraints. Simulation results further demonstrate the efficiency of the proposed method in end-effector path tracking control under RCM constraints based on a redundant manipulator.


2020 ◽  
Vol 11 (6) ◽  
pp. 330-334
Author(s):  
R. A. Karelova ◽  
◽  
E. E. Ignatov ◽  

The article presents an embodiment of an artificial neural network for recognizing defects in images of steel sheets. Several stages of solving the problem are described: the choice of a development environment, a programming language, and libraries necessary for the implementation; features of data analysis, graphing, histograms, finding dependencies; the selection of a suitable neural network, the choice of neural network architecture, the selection of an algorithm for assessing quality and accuracy; neural network spelling; training and checking accuracy and quality, checking for overfitting (retraining). As development tools, Python language, PyTorch library, Jupyter development environment, convolutional neural network architecture — Unet are proposed. Features of the analysis of input images of steel sheets, features of the implementation of the neural network itself are described. The function of binary cross entropy was chosen as a criterion for assessing accuracy, since it seeks to bring the distribution of the network forecast to the target, fine not only for erroneous predictions, but also for uncertain ones. For additional evaluation, the DICE method was also used. The accuracy of the resulting model is 84 %. The proposed solution can become part of a hardware-software system for automating the recognition of defects on metal sheets.


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