Investigation of the Transient Characteristics for Laser Cladding Beads Using 420 Stainless Steel Powder

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
S. M. Saqib ◽  
R. J. Urbanic
Keyword(s):  
Real Time ◽  
Laser Cladding ◽  
Process Planning ◽  
Control Strategies ◽  
Steel Powder ◽  
Process Models ◽  
Bead Geometry ◽  
Real Time Control ◽  
Transient Conditions ◽  
Simulation Tools

To understand the different aspects of the laser cladding (LC) process, process models can be of aid. Presently, the correct parameter settings for different manufacturing processes, such as machining and casting, are based on simulation tools that can evaluate the influence of the process parameters for different conditions. However, there are no comprehensive, focused simulation process planning tools available for the LC process. In the past, most of the research has focused on the experimentally based optimization strategies for a process configuration, typically for a single track bead in steady-state conditions. However, an understanding of realistic transient conditions needs to be explored for effective process planning simulation tools and build strategies to be developed. A set of cladding experiments have been performed for single and multiple bead scenarios, and the effects of the transient conditions on the bead geometry for these scenarios have been investigated. It is found that the lead-in and lead-out conditions differ, corner geometry influences the bead height, and when changing the input power levels, the geometry values oscillate differently than the input pulses. Changes in the bead geometry are inherent when depositing material; consequently, real-time adjustments for the process setting are essential. The dynamic, time varying heating and solidification, for multiple layer scenarios, leads to challenging process planning and real-time control strategies.

Utilizing a Numerical Simulation to Model a Step Function Response for 420 Stainless Steel Powder Laser Cladding

2017 ◽  
Author(s):  
Navid Nazemi ◽  
Ruth Jill Urbanic ◽  
Syed Saqib
Keyword(s):  
Stainless Steel ◽  
Laser Cladding ◽  
Simulation Models ◽  
Steel Powder ◽  
Power Input ◽  
Stainless Steel Powder ◽  
Bead Geometry ◽  
Functional Requirements ◽  
Real Time Control ◽  
Transient Conditions

To develop realistic process planning simulation tools and build strategies, an understanding of realistic transient conditions needs to be explored for multiple overlapping beads and 3D build ups. In the past, most of the research has focused on optimization strategies for a process configuration, typically for a single-track bead in steady state conditions. Changes in the bead geometry are inherent when depositing material; consequently, understanding dynamic, time varying heating and solidification conditions for multiple bead scenarios needs to be investigated. It is important to understand the system characteristics and its influence on the all the bead geometry parameters (not just the width) and the resultant hardness. Initially, a set of physical laser cladding experiments have been performed for single and multiple bead scenarios using 420 stainless steel powder being deposited onto mild steel plate with step variations being applied for the process power. For this research, complementary simulation models are developed, and the effects of the transient conditions on the bead hardness for several scenarios are investigated for four process power input step-functions using an imposed thermal cycling simulation approach. It is observed that the hardness values change from higher to lower values between the first and third beads, and for all scenarios, the hardness converges to a uniform value. When comparing geometry and hardness results, it can be seen that the geometry has more oscillations than the hardness. More research in this area is essential to develop robust real-time control solutions that encompass functional requirements such as hardness as well as the bead geometry.

Pollution based real time control strategies for combined sewer systems

1997 ◽  
Vol 36 (8-9) ◽  
pp. 331-336 ◽  
Author(s):  
Gabriela Weinreich ◽  
Wolfgang Schilling ◽  
Ane Birkely ◽  
Tallak Moland
Keyword(s):  
Real Time ◽  
Control Strategies ◽  
Ammonia Nitrogen ◽  
Simple Extension ◽  
Real Time Control ◽  
Time Control ◽  
Sewer Systems ◽  
Receiving Waters ◽  
Tunnel System

This paper presents results from an application of a newly developed simulation tool for pollution based real time control (PBRTC) of urban drainage systems. The Oslo interceptor tunnel is used as a case study. The paper focuses on the reduction of total phosphorus Ptot and ammonia-nitrogen NH4-N overflow loads into the receiving waters by means of optimized operation of the tunnel system. With PBRTC the total reduction of the Ptot load is 48% and of the NH4-N load 51%. Compared to the volume based RTC scenario the reductions are 11% and 15%, respectively. These further reductions could be achieved with a relatively simple extension of the operation strategy.

Dynamic modeling, system identification and comparative study of various control strategies for a spatial parallel manipulator

2021 ◽  
pp. 095965182110320
Author(s):  
Mervin Joe Thomas ◽  
Shoby George ◽  
Deepak Sreedharan ◽  
ML Joy ◽  
AP Sudheer
Keyword(s):  
Real Time ◽  
Parallel Manipulator ◽  
Control Strategies ◽  
Proportional Integral Derivative ◽  
Real Time Control ◽  
Model Predictive Controller ◽  
End Effector ◽  
Proportional Integral ◽  
Time Control ◽  
Predictive Controller

The significant challenges seen with the mathematical modeling and control of spatial parallel manipulators are its difficulty in the kinematic formulation and the inability to real-time control. The analytical approaches for the determination of the kinematic solutions are computationally expensive. This is due to the passive joints, solvability issues with non-linear equations, and inherent kinematic constraints within the manipulator architecture. Therefore, this article concentrates on an artificial neural network–based system identification approach to resolve the complexities of mathematical formulations. Moreover, the low computation time with neural networks adds up to its advantage of real-time control. Besides, this article compares the performance of a constant gain proportional–integral–derivative (PID), variable gain proportional–integral–derivative, model predictive controller, and a cascade controller with combined variable proportional–integral–derivative and model predictive controller for real-time tracking of the end-effector. The control strategies are simulated on the Simulink model of a 6-degree-of-freedom 3-PPSS (P—prismatic; S—spherical) parallel manipulator. The simulation and real-time experiments performed on the fabricated manipulator prototype indicate that the proposed cascade controller with position and velocity compensation is an appropriate method for accurate tracking along the desired path. Also, training the network using the experimentally generated data set incorporates the mechanical joint approximations and link deformities present in the fabricated model into the predicted results. In addition, this article showcases the application of Euler–Lagrangian formalism on the 3-PPSS parallel manipulator for its dynamic model incorporating the system constraints. The Lagrangian multipliers include the influence of the constraint forces acting on the manipulator platform. For completeness, the analytical model results have been verified using ADAMS for a pre-defined end-effector trajectory.

Performance evaluation of a full-scale advanced phase isolation ditch process by using real-time control strategies

2014 ◽  
Vol 31 (4) ◽  
pp. 611-618 ◽  
Author(s):  
Hyosoo Kim ◽  
Yejin Kim ◽  
Minsoo Kim ◽  
Wenhua Piao ◽  
Jeasung Gee ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Real Time ◽  
Control Strategies ◽  
Full Scale ◽  
Real Time Control ◽  
Time Control ◽  
Advanced Phase

Astlingen – a benchmark for real time control (RTC)

2018 ◽  
Vol 2017 (2) ◽  
pp. 552-560 ◽  
Author(s):  
Manfred Schütze ◽  
Maja Lange ◽  
Michael Pabst ◽  
Ulrich Haas
Keyword(s):  
Real Time ◽  
Preliminary Analysis ◽  
Control Strategies ◽  
Treatment Plant ◽  
Drainage System ◽  
Real Time Control ◽  
Sewer System ◽  
Time Control ◽  
System 2 ◽  
Water Association

Abstract This contribution serves two purposes. (1) It presents an updated version of the Astlingen example developed by the working group ‘Integral Real Time Control’ of the German Water Association (DWA), which serves as a benchmark example for the setup and evaluation of real time control strategies. As this benchmark is also intended for educational use, it demonstrates a simple RTC algorithm, illustrating the main concepts of RTC of drainage system. (2) The paper also encourages the preliminary analysis of the potential feasibility and benefit of a temporal increase of inflow to the wastewater treatment plant (WWTP) before analysing the WWTP behaviour in detail. For the present example, RTC within the sewer system alone led to almost the same reduction of overflow volume as permitting the inflow to the WWTP to be increased for 6 h within any 24 h, if at all permitted.

scholarly journals An MPC-Enabled SWMM Implementation of the Astlingen RTC Benchmarking Network

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1034 ◽  
Author(s):  
Congcong Sun ◽  
Jan Lorenz Svensen ◽  
Morten Borup ◽  
Vicenç Puig ◽  
Gabriela Cembrano ◽  
...  
Keyword(s):  
Real Time ◽  
Control Strategies ◽  
Real Time Control ◽  
Time Control ◽  
Advanced Control ◽  
Water Association ◽  
Benchmark System ◽  
Receiving Waters ◽  
Global Strategies ◽  
Swmm Model

The advanced control of urban drainage systems (UDS) has great potential in reducing pollution to the receiving waters by optimizing the operations of UDS infrastructural elements. Existing controls vary in complexity, including local and global strategies, Real-Time Control (RTC) and Model Predictive Control (MPC). Their results are, however, site-specific, hindering a direct comparison of their performance. Therefore, the working group ‘Integral Real-Time Control’ of the German Water Association (DWA) developed the Astlingen benchmark network, which has been implemented in conceptual hydrological models and applied to compare RTC strategies. However, the level of detail of such implementations is insufficient for testing more complex MPC strategies. In order to provide a benchmark for MPC, this paper presents: (1) The implementation of the conceptual Astlingen system in an open-source hydrodynamic model (EPA-SWMM), and (2) the application of an MPC strategy to the developed SWMM model. The MPC strategy was tested against traditional and well-established local and global RTC approaches, demonstrating how the proposed benchmark system can be used to test and compare complex control strategies.

scholarly journals Development of a test-bed to implement and validate real-time control strategies for aerial vehicles*

2011 ◽  
Vol 44 (1) ◽  
pp. 7660-7665
Author(s):  
A. Berna ◽  
P. Castillo ◽  
G. Sanahuja ◽  
F. González ◽  
P. García ◽  
...  
Keyword(s):  
Real Time ◽  
Control Strategies ◽  
Test Bed ◽  
Real Time Control ◽  
Time Control ◽  
Aerial Vehicles
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