Indirect Strain Control in Aluminum Stamp Formed Pans

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
William J. Emblom
Keyword(s):  
Control System ◽  
Feedback Loop ◽  
Closed Loop ◽  
Open Loop ◽  
Smith Predictor ◽  
Forming Limit ◽  
Closed Loop Control ◽  
Blank Holder ◽  
Loop Control ◽  
Critical Regions

A stamp forming die whose flexible blank holder (BH) was designed using finite element (FE) analysis was built. The tooling also included active draw beads, local wrinkling sensors, and local force transducers. Wrinkling was controlled using a proportional–integral–derivative (PID) feedback loop and blank holder force (BHF). Local forces in the tooling were also controlled using blank holder forces in a PID feedback loop. A third closed-loop control system that could be used to control local punch forces (LPF) near draw beads featured an advanced PID controller with a Smith Predictor and Kalman Filter. A Bang–bang controller was also incorporated into that control system in order to prevent control saturation. Fuzzy logic was used to transition from one controller to the other. Once closed-loop control was implemented, tests were performed in order to evaluate the strains in the pans for various forming conditions. These results were compared to open-loop tests and it was found that the strains' paths for closed-loop control tests resulted in convergence and were further from the forming limit than strains from open-loop control tests. Furthermore, it was seen that the strains in critical regions had more uniform strain fields once closed-loop control of local punch forces was implemented. Hence, it was concluded that controlling local punch forces resulted in the indirect control of strains in critical regions.

Strains in Aluminum Stamp Formed Pans Resulting From Closed-Loop Control of Local Forces

2015 ◽  
Author(s):  
William J. Emblom
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Open Loop ◽  
Smith Predictor ◽  
Forming Limit ◽  
Closed Loop Control ◽  
Blank Holder ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System

A stamp forming die, whose flexible blank holder was designed using FEA, was built. A closed-loop control system was used to control local punch forces and wrinkling by controlling both blank holder forces and draw bead penetration. The controllers for the draw beads featured an advanced PID controller with a Smith Predictor and Kalman Filter. A Bang-bang controller was also incorporated into the control system in order prevent control saturation. Fuzzy logic was used to transition from once controller to the other. Once closed-loop was implemented, tests were performed to evaluate the strains in the pans for various forming conditions. These results were compared to open-loop tests and it was found that the strains measured from closed-loop control tests resulted in more uniform strains and that the strains were further from the forming limit curves than strains from tests that were performed under open-loop conditions. Furthermore, it was seen that the strains in the regions were local force were controlled resulted in more uniform strain fields. Hence it was concluded that controlling local punch forces resulted in the strain control of critical regions.

Robustness for Intelligent Tooling While Forming Shallow Aluminum Pans

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
William J. Emblom
Keyword(s):  
Control System ◽  
Design Process ◽  
Closed Loop ◽  
Open Loop ◽  
Closed Loop Control ◽  
Blank Holder ◽  
Loop Control ◽  
Stamp Forming ◽  
Tooling Design ◽  
Process Disturbances

This study examines the robustness of stamp forming tooling. An oval pan was formed using tooling that included a flexible blank holder, active draw beads, and closed-loop control of both wrinkling and local punch forces. The results were compared to open-loop tests using the same tooling and earlier work that utilized tooling that produced similar pans but included a rigid blank holder. For the current study, robustness was defined as the ability to delay wrinkling or tearing. A description of the tooling design process is provided as well as a synopsis of the development of the control system for the tooling. Open-loop and closed-control tests using AL 6111-T4 blanks were performed in order to evaluate the ability to reject process disturbances and demonstrate improved robustness of the tooling. During open-loop tests, the current tooling was shown to be more robust than the earlier tooling with the rigid blank holder. Control of wrinkling eliminated one form of part failure while closed-loop control of local punch forces significantly improved the robustness of the tooling by delaying tearing.

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.

The Effect of Local Force Control on Punch Forces During Panel Forming

2018 ◽  
Author(s):  
William J. Emblom
Keyword(s):  
Closed Loop ◽  
Force Transducer ◽  
Open Loop ◽  
Control Panel ◽  
Closed Loop Control ◽  
Punch Force ◽  
Blank Holder ◽  
Loop Control ◽  
Operational Envelope ◽  
And Control

Methods for improving the robustness of panel forming including the introduction of process sensing and feedback and control has resulted in significant gains in the quality of parts and reduced failures. Initial efforts in implementing closed-loop control during panel forming used active tool elements to ensure that the total punch force followed prescribed trajectories. However, more recently local forces within the tooling have been demonstrated to not only follow desired force trajectories but have been shown to increase the operational envelope of the tooling compared to open-loop tests and even closed-loop test where the total punch force had been controlled. However, what has not been examined is the effect of local force, especially during closed-loop control panel forming operations on the total punch force measured during forming. This paper addresses this by comparing the results of both open-loop tests and closed-loop tests and examining the effects on both local and total punch forces. It was found that while open-loop forming with various constant draw bead depths resulted in varying total punch forces, once closed-loop control was implemented the total punch forces followed virtually identical trajectories. The tooling for this project included local force transducers and a total punch force transducer. In addition, active draw beads could be controlled during forming and a flexible blank holder with variable blank holder forces were part of the setup.

Strain Control in an Intelligent Die Based Upon Local Force Control and Blank Holder Forces

2009 ◽  
Author(s):  
William J. Emblom ◽  
Klaus J. Weinmann ◽  
John E. Beard
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
Die Design ◽  
Closed Loop Control ◽  
Blank Holder Force ◽  
Punch Force ◽  
Blank Holder ◽  
Loop Control ◽  
And Control ◽  
Bead Penetration

An experimental evaluation of the strains in an oval stamp forming die is presented. The die design included a flexible blank holder and active draw beads. The die was instrumented with local punch force and wrinkle sensors and control systems were developed in order to follow local punch force and wrinkle trajectories. Strains were measured after pan forming for both open and closed-loop tests. The relation between blank holder force, draw bead penetration, and strains were explored in the critical strain region of the formed pan. Closed-loop control of the local punch forces at the die ends was established using blank holder forces. The strains for tests with various lubrication conditions and draw bead penetrations were compared. It was observed that there is a tendency for the strains in critical locations to converge or remain constant for the closed-loop control tests while the strains tended to increase with blank holder force for open-loop tests. It was concluded that by controlling local punch forces, strain is indirectly controlled.

Improved Robustness Through Closed-Loop Control for Aluminum Sheet Metal Stamp Forming

2008 ◽  
Author(s):  
William J. Emblom ◽  
Klaus J. Weinmann
Keyword(s):  
Closed Loop ◽  
Experimental Tests ◽  
Open Loop ◽  
Closed Loop Control ◽  
Punch Force ◽  
Blank Holder ◽  
Loop Control ◽  
Stamp Forming ◽  
Process Disturbances ◽  
Bead Height

A stamp forming die, whose flexible blank holder was designed using FEA, was built. Tests were performed to evaluate the robustness of the die once closed-loop control was implemented. These results were compared to the results of open-loop tests presented earlier. The closed-loop tests were designed to determine the die and control system’s ability to reject process disturbances and demonstrate improved robustness in stamp forming when using a flexible blank holder and closed-loop control. Draw beads were used to control local punch forces and blank holder forces were used to control wrinkling. Experimental tests for the die demonstrated that closed-loop control of local punch forces using active draw beads improves robustness of the die. Two different lubricants and varying quantities of lubricant were evaluated for this study. Additionally, the ability to simultaneously use draw bead height to control local punch force and blank holder force to control wrinkles was demonstrated.

Research on the Control System of Ecological Architecture

2012 ◽  
Vol 174-177 ◽  
pp. 3196-3201
Author(s):  
Bo Xia
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Open Loop ◽  
Closed Loop Control ◽  
Open Loop Control ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Ecological Architecture ◽  
Building Control System

This paper proceeds from the basic conceptions of systematology and cybernetics and researches ecological architecture from one new angle. The paper divides the building control system into the open-loop control system and closed-loop control system, and further researches their principles.

CLOSED-LOOP CONTROL OF QUADRICEPS/HAMSTRING ACTIVATION FOR FES-INDUCED STANDING-UP MOVEMENT OF PARAPLEGICS

2001 ◽  
Vol 05 (03) ◽  
pp. 173-184 ◽  
Author(s):  
Nan-Ying Yu ◽  
Jia-Jin Jason Chen ◽  
Ming Shiang Ju
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Mechanical Energy ◽  
Open Loop ◽  
Knee Extensors ◽  
Joint Control ◽  
Closed Loop Control ◽  
Open Loop Control ◽  
Loop Control ◽  
Standing Up

Functional electrical stimulation (FES) standing system can enable the paraplegics to achieve the standing position for functional activities in daily living. FES standing system is usually applied by stimulating the knee extensor muscles. The hip joints are in hyperextension and the ankle joints remain free. Therefore, the knee joint control is the key point of the FES standing control system. Traditional open-loop control often induces high knee end-velocity (KEV) when the subject reaches the upright position. In this work, the reducing of KEV by closed-loop control was addressed. An on/off feedback control based on mechanical energy conservation was developed to control the knee extensors and flexors. The result was compared to the open loop controlled standing up in a mechanically simulative experiment. It is concluded that the on/off control strategy can reduce the KEV more efficiently when compared to the open-loop control. Proportional-integral-derivative (PID) position controlled standing up was also studied and compared with the on/off control system. The PID controller was found to be capable of reducing KEV to a level lower than that of the on/off control, whereas its instability for knee control was also found.

Closed-Loop Control System for Blank Holder Forces in Deep Drawing

CIRP Annals ◽  
1995 ◽  
Vol 44 (1) ◽  
pp. 251-254 ◽  
Author(s):  
K. Siegert ◽  
E. Dannenmann ◽  
S. Wagner ◽  
A. Galaiko
Keyword(s):  
Control System ◽  
Deep Drawing ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Blank Holder ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System
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