scholarly journals Active Compliant PID Learning Control for Grinding Robots

2021 ◽  
Vol 40 (4) ◽  
pp. 747-752
Author(s):  
Lubna Farhi ◽  
Farhan Ur Rehman
Keyword(s):  
Learning Algorithm ◽  
Tracking Error ◽  
Learning Control ◽  
Pid Controllers ◽  
Robotic Grinding ◽  
Controller Gain ◽  
Grinding Mechanism ◽  
The Subject ◽  
Subject Material ◽  
Grinding System

This article proposes a Proportional, Integral, and Derivative (PID) learning controller for rigid robotic disk grinding mechanism. It has been observed that the stiffness of the robotic arm for a grinder has a direct correlation with the sensitivity of the grinding forces. It is also drastically influenced by the end-effector path tracking error resulting in limited accuracy of the robot. The error in robot’s accuracy is also increased by external interferences, such as surface imperfections and voids in the subject material. These errors can be mitigated via efficient feedback. In the proposed methodology, the controller gain is tuned by implementing a learning-based methodology to PID controllers. The learning control for the robotic grinding system helps by progressively decreasing error between the actual grinded paths and required trace. Experimental results demonstrate that as the grinder machines the required path iteratively, its grinding accuracy improves due to the learning algorithm.

Iterative Learning Control for Nonlinear Nonminimum Phase Plants1

1998 ◽  
Vol 123 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Jayati Ghosh ◽  
Brad Paden
Keyword(s):  
Learning Algorithm ◽  
Tracking Error ◽  
Learning Control ◽  
Inversion Method ◽  
Simulation Studies ◽  
Nonminimum Phase ◽  
Robust Learning ◽  
Random Disturbances ◽  
Nonlinear Plants ◽  
Generic Family

Learning control is a very effective approach for tracking control in processes occurring repetitively over a fixed interval of time. In this paper a robust learning algorithm is proposed for a generic family of nonlinear, nonminimum phase plants with disturbances and initialization error. The “stable-inversion” method of Devasia, Chen and Paden is applied to develop a learning controller for linear nonminimum phase plants. This is adapted to accommodate a more general class of nonlinear plants. The bounds on the asymptotic error for the learned input are exhibited via a concise proof. Simulation studies demonstrate that in the absence of input disturbances, perfect tracking of the desired trajectory is achieved for nonlinear nonminimum phase plants. Further, in the presence of random disturbances, the tracking error converges to a neighborhood of zero. A bound on the tracking error is derived which is a continuous function of the bound on the disturbance. It is also observed that perfect tracking of the desired trajectory is achieved if the input disturbance is the same at every iteration.

Specimen Collection Effect in Scanning Electron Microscopy Images

1972 ◽  
Vol 30 ◽  
pp. 448-449
Author(s):  
J. Temple Black ◽  
Jose Guerrero
Keyword(s):  
Surface Morphology ◽  
Secondary Electron Emission ◽  
Secondary Electrons ◽  
Charge Effects ◽  
Material Density ◽  
Specimen Collection ◽  
The Subject ◽  
Curved Paths ◽  
Subject Material ◽  
Microscopy Images

In the SEM, contrast in the image is the result of variations in the volume secondary electron emission and backscatter emission which reaches the detector and serves to intensity modulate the signal for the CRT's. This emission is a function of the accelerating potential, material density, chemistry, crystallography, local charge effects, surface morphology and especially the angle of the incident electron beam with the particular surface site. Aside from the influence of object inclination, the surface morphology is the most important feature In producing contrast. “Specimen collection“ is the name given the shielding of the collector by adjacent parts of the specimen, producing much image contrast. This type of contrast can occur for both secondary and backscatter electrons even though the secondary electrons take curved paths to the detector-collector.Figure 1 demonstrates, in a unique and striking fashion, the specimen collection effect. The subject material here is Armco Iron, 99.85% purity, which was spark machined.

Classification and Recognition of Electronic Components Based on Improved Cooperative Semi-supervised Learning Algorithm

2020 ◽  
Vol 14 ◽  
Author(s):  
Dan Luo
Keyword(s):  
Deep Learning ◽  
Machine Vision ◽  
Supervised Learning ◽  
Image Recognition ◽  
Production Efficiency ◽  
Learning Algorithm ◽  
Electronic Components ◽  
Electron Device ◽  
Actual Recognition ◽  
The Subject

Background: As known that the semi-supervised algorithm is a classical algorithm in semi-supervised learning algorithm. Methods: In the paper, it proposed improved cooperative semi-supervised learning algorithm, and the algorithm process is presented in detailed, and it is adopted to predict unlabeled electronic components image. Results: In the experiments of classification and recognition of electronic components, it show that through the method the accuracy the proposed algorithm in electron device image recognition can be significantly improved, the improved algorithm can be used in the actual recognition process . Conclusion: With the continuous development of science and technology, machine vision and deep learning will play a more important role in people's life in the future. The subject research based on the identification of the number of components is bound to develop towards the direction of high precision and multi-dimension, which will greatly improve the production efficiency of electronic components industry.

South Sea Tales

2008 ◽  
Author(s):  
Robert Louis Stevenson
Keyword(s):  
Nineteenth Century ◽  
Cross Cultural ◽  
Robert Louis Stevenson ◽  
Global Culture ◽  
Cultural Encounters ◽  
Post Colonial ◽  
The Pacific ◽  
South Sea ◽  
The Subject ◽  
Subject Material

The literary world was shocked when in 1889, at the height of his career, Robert Louis Stevenson announced his intention to settle permanently on the Pacific island of Samoa. His readers were equally shocked when he began to use the subject material offered by his new environment, not to promote a romance of empire, but to produce some of the most ironic and critical treatments of imperialism in nineteenth-century fiction. In these stories, as in his work generally, Stevenson shows himself to be a virtuoso of narrative styles: his Pacific fiction includes the domestic realism of ‘The Beach at Falesé, the folktale plots of ‘The Bottle Imp’ and ‘The Isle of Voices’, and the modernist blending of naturalism and symbolism in The Ebb-Tide. But beyond their generic diversity the stories are linked by their concern with representing the multiracial society of which their author had become a member. In this collection - the first to bring together all his shorter Pacific fiction in one volume - Stevenson emerges as a witness both to the cross- cultural encounters of nineteenth-century imperialism and to the creation of the global culture which characterizes the post-colonial world.

Iterative learning control algorithm for sensor fault nonlinear systems

2020 ◽  
pp. 1-8
Author(s):  
Zimian Lan
Keyword(s):  
Nonlinear Systems ◽  
Iterative Learning Control ◽  
Control Algorithm ◽  
Tracking Error ◽  
Learning Control ◽  
Open Loop ◽  
Iterative Learning ◽  
Sensor Fault ◽  
Initial State ◽  
Control Gain

In this paper, we propose a new iterative learning control algorithm for sensor faults in nonlinear systems. The algorithm does not depend on the initial value of the system and is combined with the open-loop D-type iterative learning law. We design a period that shortens as the number of iterations increases. During this period, the controller corrects the state deviation, so that the system tracking error converges to the boundary unrelated to the initial state error, which is determined only by the system’s uncertainty and interference. Furthermore, based on the λ norm theory, the appropriate control gain is selected to suppress the tracking error caused by the sensor fault, and the uniform convergence of the control algorithm and the boundedness of the error are proved. The simulation results of the speed control of the injection molding machine system verify the effectiveness of the algorithm.

scholarly journals Dentoskeletal Effects and “Effective” Temporomandibular Joint, Maxilla and Chin Changes in Good and Bad Responders to van Beek Activator Treatment

2007 ◽  
Vol 77 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Sabine Ruf ◽  
Margareta Bendeus ◽  
Hans Pancherz ◽  
Urban Hägg
Keyword(s):  
Temporomandibular Joint ◽  
Class Ii ◽  
Good Responder ◽  
Skeletal Changes ◽  
Maxillary Molars ◽  
Division 1 ◽  
The Subject ◽  
Subject Material ◽  
Lateral Head ◽  
Lower Incisors

Abstract Objective: To assess possible differences in dentoskeletal effects and “effective” temporomandibular joint, maxilla, and chin changes between good and bad responders to van Beek activator treatment. Materials and Methods: The subject material consisted of 20 consecutive normodivergent male Class II division 1 patients treated with a van Beek activator. Because of insufficient cooperation, four patients were excluded. Lateral head films were taken 6 months before treatment, at start of treatment, and after 12 months of treatment. The patients were placed into a good responder group (successful, n = 8) and a bad responder group (unsuccessful, n = 8). An overjet reduction ≥4 mm was considered successful. Results: During the van Beek treatment period, the good responders showed a significantly larger improvement in overjet and molar relationship than did the bad responders. The good responders exhibited a significant posterior development of condylion, less anterior mandibular autorotation, retrusion of upper incisors, protrusion of lower incisors, distalization of maxillary molars, and a mesial movement of mandibular molars. No significant dental movements were seen in the bad responders. Conclusions: Although van Beek activator treatment affected the direction of condylar growth, as well as the direction of maxilla and chin changes, it can be concluded that skeletal changes did not contribute to the Class II correction. Instead, overjet reduction during van Beek activator treatment was found to be due to a favorable dental reaction.

Dynamic modeling and design of controller for the 2-DoF serial chain actuated by a cable-driven robot based on feedback linearization

2021 ◽  
pp. 095440622110279
Author(s):  
Vahid Bahrami ◽  
Ahmad Kalhor ◽  
Mehdi Tale Masouleh
Keyword(s):  
Dynamic Modeling ◽  
Pid Controller ◽  
Feedback Linearization ◽  
Tracking Error ◽  
Pid Controllers ◽  
Serial Chain ◽  
Simulation Results ◽  
The Stability ◽  
Feedback Linearization Approach ◽  
Bounded Disturbance

This study intends to investigate a dynamic modeling and design of controller for a planar serial chain, performing 2-DoF, in interaction with a cable-driven robot. The under study system can be used as a rehabilitation setup which is helpful for those with arm disability. The latter goal can be achieved by applying the positive tensions of the cable-driven robot which are designed based on feedback linearization approach. To this end, the system dynamics formulation is developed using Lagrange approach and then the so-called Wrench-Closure Workspace (WCW) analysis is performed. Moreover, in the feedback linearization approach, the PD and PID controllers are used as auxiliary controllers input and the stability of the system is guaranteed as a whole. From the simulation results it follows that, in the presence of bounded disturbance based on Roots Mean Square Error (RMSE) criteria, the PID controller has better performance and tracking error of the 2-DoF robot joints are improved 15.29% and 24.32%, respectively.

Iterative learning algorithm with a quadratic criterion for linear time-varying systems

2002 ◽  
Vol 216 (3) ◽  
pp. 309-316 ◽  
Author(s):  
S N Huang ◽  
K K Tan ◽  
T H Lee
Keyword(s):  
Learning Algorithm ◽  
Linear Time ◽  
Tracking Error ◽  
Iterative Learning ◽  
Tracking Performance ◽  
Time Varying ◽  
Control Scheme ◽  
Time Varying Systems ◽  
Simulation Results ◽  
Learning Law

A novel iterative learning controller for linear time-varying systems is developed. The learning law is derived on the basis of a quadratic criterion. This control scheme does not include package information. The advantage of the proposed learning law is that the convergence is guaranteed without the need for empirical choice of parameters. Furthermore, the tracking error on the final iteration will be a class K function of the bounds on the uncertainties. Finally, simulation results reveal that the proposed control has a good setpoint tracking performance.

scholarly journals Online Optimal Control of Robotic Systems with Single Critic NN-Based Reinforcement Learning

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Xiaoyi Long ◽  
Zheng He ◽  
Zhongyuan Wang
Keyword(s):  
Optimal Control ◽  
Reinforcement Learning ◽  
Tracking Control ◽  
Learning Algorithm ◽  
Tracking Error ◽  
Adaptive Dynamic Programming ◽  
Robotic Systems ◽  
Control Synthesis ◽  
Optimal Tracking ◽  
Optimal Tracking Control

This paper suggests an online solution for the optimal tracking control of robotic systems based on a single critic neural network (NN)-based reinforcement learning (RL) method. To this end, we rewrite the robotic system model as a state-space form, which will facilitate the realization of optimal tracking control synthesis. To maintain the tracking response, a steady-state control is designed, and then an adaptive optimal tracking control is used to ensure that the tracking error can achieve convergence in an optimal sense. To solve the obtained optimal control via the framework of adaptive dynamic programming (ADP), the command trajectory to be tracked and the modified tracking Hamilton-Jacobi-Bellman (HJB) are all formulated. An online RL algorithm is the developed to address the HJB equation using a critic NN with online learning algorithm. Simulation results are given to verify the effectiveness of the proposed method.

scholarly journals Fundamentos del método científico

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
M. H Badii ◽  
A. R. Pazhakh ◽  
José Luis Abreu Quintero ◽  
R Foroughbakhch
Keyword(s):  
Data Collection ◽  
Research Methodology ◽  
Literature Search ◽  
Ethical Issues ◽  
Scientific Work ◽  
Scientific Methodology ◽  
The Subject ◽  
Basic Concepts ◽  
Points Of View ◽  
Subject Material

Palabras claves: Ciencia, ECOEE, investigación, métodosResumen. El objetivo de esta obra no radica en realizar una búsqueda exhaustiva de la literatura en el tema, sino, sentar las bases del método científico, notando los aspectos filosóficos e éticos de la ciencia. Se presentan los conceptos y definiciones fundamentales relacionados con la metodología de la investigación científica. Se maneja el concepto de la toma de los datos válidos como un requisito básico en cualquier trabajo científico. Se pone a disposición del lector un modelo denominado el ECOEE que es una herramienta poderosa para establecer puntos de comparación e discusión entre los resultados de diferentes trabajos científicos. Finalmente, ofrece unas sugerencias de que hacer o no hacer en cuanto a realizar un trabajo de investigación.Key words: ECOEE, methods, research, Science Abstract.The aim of this paper is not to conduct a thorough literature search on the subject material, but to stress the fundamentals of the scientific methodology along with the philosophical and ethical issues thereof. The basic concepts and definitions in relation to research methodology are presented. The concept of data collection as a basic requisite in any scientific work is discussed. The ECOEE model as a strong tool in establishing different points of view and comparison among the results of different scientific works are laid out. Finally, some tips and suggestions are given as what to do or to avoid in conducting scientific research.

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