Automatic Control to Prevent Thermal Runaway During Microwave Joining of Ceramics

1992 ◽  
Vol 269 ◽  
Author(s):  
Guy O. Beale ◽  
Francisco J. Arteaga
Keyword(s):  
Control System ◽  
Model Equation ◽  
Closed Loop ◽  
Thermal Runaway ◽  
Temperature Control System ◽  
Closed Loop Control ◽  
High Quality ◽  
Loop Control ◽  
Heating Model ◽  
Linearized Model

ABSTRACTA temperature control system is designed and simulated for microwave joining of ceramics. The objective is to develop a control system for reliable, high quality joints to be produced on a variety of ceramics. The described procedure permits the derivation of a closed-loop configuration for controlling temperature. The ceramics (alumina) heating model equation is linearized around an operating point and represented as a transfer function. Conditions for closed-loop stability with any linearized model are presented and mathematically proven. A computer simulation is implemented for the closed-loop control and numerical integration is used for solving the non-linear heating equations. Results are very good and show that the temperature can be regulated to a set point value and thermal runaway in the ceramics can be prevented.

Combined Temperature and Force Control for Robotic Friction Stir Welding

2013 ◽  
Author(s):  
Axel Fehrenbacher ◽  
Christopher B. Smith ◽  
Neil A. Duffie ◽  
Nicola J. Ferrier ◽  
Frank E. Pfefferkorn ◽  
...  
Keyword(s):  
Control System ◽  
Force Control ◽  
Closed Loop ◽  
Interface Temperature ◽  
Closed Loop Control ◽  
Weld Quality ◽  
Loop Control ◽  
Friction Stir ◽  
Tool Position ◽  
Robotic Friction Stir Welding

The objective of this research is to develop a closed-loop control system for robotic friction stir welding (FSW) that simultaneously controls force and temperature in order to maintain weld quality under various process disturbances. FSW is a solid-state joining process enabling welds with excellent metallurgical and mechanical properties, as well as significant energy consumption and cost savings compared to traditional fusion welding processes. During FSW, several process parameter and condition variations (thermal constraints, material properties, geometry, etc.) are present. The FSW process can be sensitive to these variations, which are commonly present in a production environment; hence, there is a significant need to control the process to assure high weld quality. Reliable FSW for a wide range of applications will require closed-loop control of certain process parameters. A linear multi-input-multi-output process model has been developed that captures the dynamic relations between two process inputs (commanded spindle speed and commanded vertical tool position) and two process outputs (interface temperature and axial force). A closed-loop controller was implemented that combines temperature and force control on an industrial robotic FSW system. The performance of the combined control system was demonstrated with successful command tracking and disturbance rejection. Within a certain range, desired axial forces and interface temperatures are achieved by automatically adjusting the spindle speed and the vertical tool position at the same time. The axial force and interface temperature is maintained during both thermal and geometric disturbances and thus weld quality can be maintained for a variety of conditions in which each control strategy applied independently could fail.

scholarly journals Closed-loop control system for well-defined oxygen supply in micro-physiological systems

2017 ◽  
Vol 3 (2) ◽  
pp. 363-366
Author(s):  
Tobias Steege ◽  
Mathias Busek ◽  
Stefan Grünzner ◽  
Andrés Fabían Lasagni ◽  
Frank Sonntag
Keyword(s):  
Control System ◽  
Oxygen Supply ◽  
Closed Loop ◽  
Microfluidic System ◽  
Closed Loop Control ◽  
Loop Control ◽  
Cell Vitality ◽  
Closed Loop Control System ◽  
Loop Control System

AbstractTo improve cell vitality, sufficient oxygen supply is an important factor. A deficiency in oxygen is called Hypoxia and can influence for example tumor growth or inflammatory processes. Hypoxia assays are usually performed with the help of animal or static human cell culture models. The main disadvantage of these methods is that the results are hardly transferable to the human physiology. Microfluidic 3D cell cultivation systems for perfused hypoxia assays may overcome this issue since they can mimic the in-vivo situation in the human body much better. Such a Hypoxia-on-a-Chip system was recently developed. The chip system consists of several individually laser-structured layers which are bonded using a hot press or chemical treatment. Oxygen sensing spots are integrated into the system which can be monitored continuously with an optical sensor by means of fluorescence lifetime detection.Hereby presented is the developed hard- and software requiered to control the oxygen content within this microfluidic system. This system forms a closed-loop control system which is parameterized and evaluated.

Adaptive synchronization of uncertain fractional-order chaotic systems using sliding mode control techniques

2019 ◽  
Vol 234 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Bahram Yaghooti ◽  
Ali Siahi Shadbad ◽  
Kaveh Safavi ◽  
Hassan Salarieh
Keyword(s):  
Control System ◽  
Sliding Mode Control ◽  
Fractional Order ◽  
Chaotic Systems ◽  
Closed Loop ◽  
Sliding Mode ◽  
Closed Loop Control ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System

In this article, an adaptive nonlinear controller is designed to synchronize two uncertain fractional-order chaotic systems using fractional-order sliding mode control. The controller structure and adaptation laws are chosen such that asymptotic stability of the closed-loop control system is guaranteed. The adaptation laws are being calculated from a proper sliding surface using the Lyapunov stability theory. This method guarantees the closed-loop control system robustness against the system uncertainties and external disturbances. Eventually, the presented method is used to synchronize two fractional-order gyro and Duffing systems, and the numerical simulation results demonstrate the effectiveness of this method.

Proved Quality by Online Monitoring and Closed-Loop Control of Pin Insertion

2015 ◽  
Vol 807 ◽  
pp. 140-149
Author(s):  
Maximiliane Erhardt ◽  
Carsten Kaschube ◽  
Markus Menacher
Keyword(s):  
Closed Loop ◽  
Online Monitoring ◽  
Robert Bosch Gmbh ◽  
Closed Loop Control ◽  
Assembly Process ◽  
High Quality ◽  
Loop Control

To provide high quality in production and assembly processes need to be controlled. This paper analyzes the effect and necessity of online monitoring and closed-loop control of pin insertion. In this investigation pin insertion is an assembly process wherein metallic pins are pressed into polymer structures. The investigations described in this paper are made at the Robert Bosch GmbH and according to their requirements towards production standards, quality and traceability.

Tangible Programming for Basic Control System New Frameworks to Engineering Education for Children

2014 ◽  
Vol 931-932 ◽  
pp. 1298-1302
Author(s):  
Thiang Meadthaisong ◽  
Siwaporn Meadthaisong ◽  
Sarawut Chaowaskoo
Keyword(s):  
Control System ◽  
Engineering Education ◽  
Control Systems ◽  
Primary Schools ◽  
Closed Loop ◽  
Open Loop ◽  
Closed Loop Control ◽  
College Level ◽  
Loop Control ◽  
Tangible Programming

Programming control in industrial design is by its nature expert upon an example being Programmable Logic Controller (PLC). Such programmes are unsuitable for children or novices as they cannot understand how to use the programme. This research seeks to present tangible programming for a basic control system in new frameworks in engineering education for children. Such programmes could be for use in kindergartens, primary schools or general teaching where knowledge about basic control is required. Normally open-loop and closed-loop control system programming is taught at university and college level. This may be late as far as acquiring knowledge of basic control systems is concerned. Using tangible programming without a computer but instructions and interface, relay and motor could result in children in kindergartens and primary schools being able to programme open-looped control systems which mix chemicals or closed-loop control systems which control conveyor belts. However, the children would not be able to undertake programming using programmable control in a similar scenario.

Sign in / Sign up

Export Citation Format

Share Document