scholarly journals Control-Oriented Characterization of Product Properties during Hot Hole-Flanging of X46Cr13 Sheet Material in a Progressive-Die

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 349
Author(s):  
Juri Martschin ◽  
Rickmer Meya ◽  
Daniel Klöser ◽  
Thomas Meurer ◽  
A. Erman Tekkaya
Keyword(s):  
Heat Treatment ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Rapid Heating ◽  
Sheet Material ◽  
Displacement Curve ◽  
Loop Control ◽  
Property Control ◽  
Hole Flanging

Robust and versatile production is enabled by a closed-loop control of product properties. This essentially relies on the characterization of the interaction between properties and available degrees of freedom to control the process. In particular, this work examines the setting of collar height, thinning, curvature, and hardness during hot hole-flanging of X46Cr13 sheet material with simultaneous heat treatment to identify approaches for a closed-loop property control in hot hole-flanging during multi-stage hot sheet metal forming. To scrutinize the adjustability of the hardness of X46Cr13 sheet material by heat treatment with rapid heating and short dwell times, quenching tests with austenitizing temperatures from 900 to 1100 °C and dwell times from 1 to 300 s were carried out. A hardness between 317 and 680 HV10 was measured. By analyzing the force-displacement curve and the contact situation between tools and blank during hot hole-flanging, an understanding for the process was established. To determine the adjustability of geometrical collar properties and the hardness of the collar, collars were formed at punch speeds between 5 and 100 mm/s and at different temperatures. Here, a dependency of the geometry of the collar on temperature and punch speed as well as setting of the hardness was demonstrated.

Adjusting of Roller Levellers by Finite Element Simulations Including a Closed-Loop Control

2014 ◽  
Vol 1018 ◽  
pp. 207-214 ◽  
Author(s):  
Markus Grüber ◽  
Marius Oligschläger ◽  
Gerhard Hirt
Keyword(s):  
Finite Element ◽  
Closed Loop ◽  
Sheet Material ◽  
Numerical Approach ◽  
Internal Stresses ◽  
Closed Loop Control ◽  
Fe Model ◽  
Production Chain ◽  
Loop Control ◽  
Curvature Measurement

Within today’s sheet processing lines, roller levellers are included in the production chain to eliminate initial curvature and reduce internal stresses of the sheet material. Despite the desire to achieve fully automated industrial processes, roller levellers still have to be set manually by an operator based on his experience and empirical data. Therefore, this paper evaluates an enhanced numerical approach to predict the vertical roll position, the so called roll intermesh, in the last load triangle. To gain the respective machine setting, a closed-loop control based on an actual curvature measurement is implemented in the finite element (FE) programme Abaqus utilising a user-subroutine. Thus, the presented FE model allows the adjustment of the roller leveller leading to a flat strip in a single simulation run within the accuracy of the FE prediction. Additionally, the FE model provides the chance to develop and test closed-loop controls for roller levelling. Complementing the results gained from the FE model, experiments have been conducted on a down-sized roller leveller with aluminium sheets (AA5005). First results obtained with the presented numerical model proved that the roll intermesh of the last load triangle was determined successfully and the use of an actual curvature measurement within the FE model provides enhanced accuracy.

scholarly journals Experimental characterization of Drobot: Towards closed-loop control

2014 ◽  
Author(s):  
Nathalie Majcherczyk ◽  
Kanty Rabenorosoa ◽  
Cedric Clevy ◽  
Rosica Mincheva ◽  
Jean-Marie Raquez ◽  
...  
Keyword(s):  
Closed Loop ◽  
Closed Loop Control ◽  
Experimental Characterization ◽  
Loop Control

A Compact 3 Degree of Freedom Spherical Joint

2011 ◽  
Vol 3 (3) ◽  
Author(s):  
Mark L. Guckert ◽  
Michael D. Naish
Keyword(s):  
Control Systems ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Degree Of Freedom ◽  
Robotic Systems ◽  
Closed Loop Control ◽  
Spherical Joint ◽  
Experimental Assessment ◽  
Loop Control ◽  
Robotic Applications

Spherical joints have evolved into a critical component of many robotic systems, often used to provide dexterity at the wrist of a manipulator. In this work, a novel 3 degree of freedom spherical joint is proposed, actuated by tendons that run along the surface of the sphere. The joint is mechanically simple and avoids mechanical singularities. The kinematics and mechanics of the joint are modeled and used to develop both open- and closed-loop control systems. Simulated and experimental assessment of the joint performance demonstrates that it can be successfully controlled in 3 degrees of freedom. It is expected that the joint will be a useful option in the development of emerging robotic applications, particularly those requiring miniaturization.

Solar Furnace Heliostat Closed-Loop Control System

2010 ◽  
Author(s):  
Kyle Glenn
Keyword(s):  
Control System ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Solar Furnace ◽  
Closed Loop Control ◽  
The Sun ◽  
Initial Alignment ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System

A 4.2 kW solar furnace heliostat was interfaced with a closed-loop control system to manipulate the azimuth and elevation rotational degrees of freedom to continuously align a solar concentrator with the sun. A QP50-6SD2 quadrant photodiode laser beam positioning device, developed by Pacific Silicon and Sensor, was modified to sense the orientation of the sun. The quadrant photodiode was mounted inside a dark box with a pinhole aperture and mounted so that when the heliostat reflects light along the desired axis, the quadrant photodiode relays balanced error signals. These error signals were interpreted with a Basic Stamp 2p40 microcontroller developed by Parallax Inc. LM741 operational amplifiers and ADC0831 analog to digital converters were used for signal conditioning. The 2p40 microcontroller interprets and checks the error signals every 500ms and uses a ULN2803 Darlington Transistor array to activate the heliostat drive motor’s solid-state relays to maintain solar alignment. The closed-loop heliostat control system can track with 1.6 degrees of accuracy. This is closer than the original prediction of 3 degrees. The control system requires user-inputs for initial alignment. Alignment can initiate with the heliostat out of alignment by at least 6 degrees. The versatility of the 2p40 allows subroutines to be programmed in that can handle hysteresis in the slewing of the heliostat, continue tracking as the heliostat begins to wobble from wind gusts, or continue tracking during intermittent shadowing from clouds.

Set-Point Generation Using Kernel-Based Methods for Closed-Loop Combustion Control of a CIDI Engine

2009 ◽  
Author(s):  
Rajaram Maringanti ◽  
Shawn Midlam-Mohler ◽  
Ming Fang ◽  
Fabio Chiara ◽  
Marcello Canova
Keyword(s):  
Steady State ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Exhaust Gas ◽  
Loop Control ◽  
Set Point ◽  
Steady State Operation ◽  
Engine Combustion ◽  
Feedback Control Systems ◽  
Homogenous Charge Compression Ignition

Closed-loop control of diesel combustion is of great interest for improving conventional Diesel engine combustion as well as facilitating new combustion modes such as Homogenous Charge Compression Ignition and other low NOx regimes. Most generalized feedback control systems that can be applied to this problem require a reference or set-point which the control attempts to achieve. Diesel engines are well known for having many degrees of freedom which poses a problem in generating valid set-points for all possible conditions encountered in practice. This problem is compounded by the fact that these set-points are usually determined in steady state operation further limiting the space where set-points can be defined. Kernel-based methods are applied to this problem as a method of generating valid setpoints when operating in regions outside of the space where set-points are defined. This is most useful during transient conditions where conditions such as exhaust gas recycle level, manifold air flow, and fuel mass are far from the steady state values.

Synthetic Esters and Dynamics of Pressure Compensated Proportional Directional Control Valves

2018 ◽  
Author(s):  
J. H. Jakobsen ◽  
M. R. Hansen
Keyword(s):  
Closed Loop ◽  
Closed Loop Control ◽  
Third Order ◽  
Loop Control ◽  
Synthetic Ester ◽  
Frequency Responses ◽  
Directional Control ◽  
Test Parameters ◽  
The Difference

The purpose of this paper is to help reduce the uncertainty in behavior introduced when changing hydraulic oil from mineral oil (HLP) to biodegradable oil (synthetic esters - HEES) by comparing the behavior of proportional valves with HLP and with HEES at various temperatures. The focus of this article is on classic proportional valves used in the industry. The study is based on tests and modelling with characterization of dynamic behavior in mind. The characterization is based on tests of two pressure compensated proportional valves, one with closed loop control of the spool position, and one without. The two ester types tested are one based on a saturated, fully synthetic ester and a regular fully synthetic ester. The tests consist of steps and frequency responses. Both valves are tested at oil temperatures 20°C, 40°C and 60°C. The adopted models are based on a third order linear model with parameters identified using frequency responses from actual valve tests. The variation of amplitude and bias has some influence on the resulting frequency response especially at lower temperatures. But the general tendencies are unaffected by amplitude and bias. As expected a clear tendency for both valves of increasing dampening at decreasing temperatures is seen regardless of oil type, but the increase in dampening is similar for all oil types. The saturated ester leads to less bandwidth at lower temperatures for both valves, but the overall variations between all oil types stay within 1.66Hz of each other when tested with the same test parameters. The investigation indicates that the difference in dynamic characteristics at 20°C caused by the different oil types can not be explained with variations in any single one of the classic liquid properties density and viscosity and more investigations are needed to identify the cause.

scholarly journals Improvement of Silicon Nanotweezers Sensitivity for Mechanical Characterization of Biomolecules Using Closed-Loop Control

2015 ◽  
Vol 20 (3) ◽  
pp. 1418-1427 ◽  
Author(s):  
Nicolas Lafitte ◽  
Yassine Haddab ◽  
Yann Le Gorrec ◽  
Herve Guillou ◽  
Momoko Kumemura ◽  
...  
Keyword(s):  
Closed Loop ◽  
Mechanical Characterization ◽  
Closed Loop Control ◽  
Loop Control

scholarly journals Exploiting short-term memory in soft body dynamics as a computational resource

2014 ◽  
Vol 11 (100) ◽  
pp. 20140437 ◽  
Author(s):  
K. Nakajima ◽  
T. Li ◽  
H. Hauser ◽  
R. Pfeifer
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Short Term Memory ◽  
Soft Materials ◽  
Computational Resource ◽  
Soft Body ◽  
Short Term ◽  
Term Memory ◽  
Loop Control ◽  
Body Dynamics

Soft materials are not only highly deformable, but they also possess rich and diverse body dynamics. Soft body dynamics exhibit a variety of properties, including nonlinearity, elasticity and potentially infinitely many degrees of freedom. Here, we demonstrate that such soft body dynamics can be employed to conduct certain types of computation. Using body dynamics generated from a soft silicone arm, we show that they can be exploited to emulate functions that require memory and to embed robust closed-loop control into the arm. Our results suggest that soft body dynamics have a short-term memory and can serve as a computational resource. This finding paves the way towards exploiting passive body dynamics for control of a large class of underactuated systems.

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