A PID tuning approach to find the optimal compromise among robustness, performance and control effort. Implementation in a free software tool

Author(s):  
Roberto Sanchis ◽  
Ignacio Pearrocha
TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 4-11
Author(s):  
MOHAMED CHBEL ◽  
LUC LAPERRIÈRE

Pulp and paper processes frequently present nonlinear behavior, which means that process dynam-ics change with the operating points. These nonlinearities can challenge process control. PID controllers are the most popular controllers because they are simple and robust. However, a fixed set of PID tuning parameters is gen-erally not sufficient to optimize control of the process. Problems related to nonlinearities such as sluggish or oscilla-tory response can arise in different operating regions. Gain scheduling is a potential solution. In processes with mul-tiple control objectives, the control strategy must further evaluate loop interactions to decide on the pairing of manipulated and controlled variables that minimize the effect of such interactions and hence, optimize controller’s performance and stability. Using the CADSIM Plus™ commercial simulation software, we developed a Jacobian sim-ulation module that enables automatic bumps on the manipulated variables to calculate process gains at different operating points. These gains can be used in controller tuning. The module also enables the control system designer to evaluate loop interactions in a multivariable control system by calculating the Relative Gain Array (RGA) matrix, of which the Jacobian is an essential part.


1996 ◽  
Vol 118 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Sergio Bittanti ◽  
Fabrizio Lorito ◽  
Silvia Strada

In this paper, Linear Quadratic (LQ) optimal control concepts are applied for the active control of vibrations in helicopters. The study is based on an identified dynamic model of the rotor. The vibration effect is captured by suitably augmenting the state vector of the rotor model. Then, Kalman filtering concepts can be used to obtain a real-time estimate of the vibration, which is then fed back to form a suitable compensation signal. This design rationale is derived here starting from a rigorous problem position in an optimal control context. Among other things, this calls for a suitable definition of the performance index, of nonstandard type. The application of these ideas to a test helicopter, by means of computer simulations, shows good performances both in terms of disturbance rejection effectiveness and control effort limitation. The performance of the obtained controller is compared with the one achievable by the so called Higher Harmonic Control (HHC) approach, well known within the helicopter community.


2000 ◽  
Vol 33 (31) ◽  
pp. 287-291
Author(s):  
Pedro Albertos ◽  
Manuel Olivares ◽  
Mario E. Salgado

Author(s):  
HYEON SOO KIM ◽  
YONG RAE KWON ◽  
IN SANG CHUNG

Software restructuring is recognized as a promising method to improve logical structure and understandability of a software system which is composed of modules with loosely-coupled elements. In this paper, we present methods of restructuring an ill-structured module at the software maintenance phase. The methods identify modules performing multiple functions and restructure such modules. For identifying the multi-function modules, the notion of the tightly-coupled module that performs a single specific function is formalized. This method utilizes information on data and control dependence, and applies program slicing to carry out the task of extracting the tightly-coupled modules from the multi-function module. The identified multi-function module is restructured into a number of functional strength modules or an informational strength module. The module strength is used as a criterion to decide how to restructure. The proposed methods can be readily automated and incorporated in a software tool.


2017 ◽  
Vol 44 ◽  
pp. 361-371 ◽  
Author(s):  
Aleš Bezrouk ◽  
Zdeněk Fiala ◽  
Lenka Kotingová ◽  
Iva Selke Krulichová ◽  
Monika Kopečná ◽  
...  

Author(s):  
Yucheng Liu ◽  
Silas Whitaker ◽  
Connor Hayes ◽  
Jared Logsdon ◽  
Logan McAfee ◽  
...  

A curriculum enhancement project of embedding MATLAB and Simulink to a mechanical engineering (ME) vibrations and controls course is presented in this paper. MATLAB/Simulink is a popular software tool for vibration analysts and control designers, which is consistently regarded as one of the most in-demand technical skills that employers are looking for. In the past, the ME students at Mississippi State University (MSU) did not have the training opportunity to use MATLAB/Simulink for design and analysis of vibration and control systems. With the support of a teaching grants, the author created an experimental lab section to ask students to design and build vibration and control devices, and integrated these device into his vibrations and controls course. In this study, the author develops a computer lab section based on the implementation of MATLAB/Simulink, which complements with the experimental lab section to provide the students with a full lab experience. The experimental-computational lab allows the students to not only observe and characterize the dynamic response of vibration and control systems through experimental operations and measurements, but also validate experimental results and confirm experimental phenomena through computational analysis. As well as exploring dynamic behaviors of the systems in a variety of conditions through numerical simulations with different settings. An example of student project is presented to show an experimental-computational study conducted by a student team using MATLAB/Simulink software tool and self-developed data acquisition systems based on a base excitation model demonstrated in class. A questionnaire was conducted at the end of that class and results confirms that the implementation of MATLAB/Simulink into the course effectively develops the ME students’ programming skills and strengthens their capacity in modeling, simulating, and analyzing vibration, control, and other dynamic systems. The developed computational lab and the current experimental lab complementarily promote student understanding of principles and concepts conveyed in classroom lectures.


2020 ◽  
Vol 10 (15) ◽  
pp. 5027 ◽  
Author(s):  
Erik Kučera ◽  
Oto Haffner ◽  
Peter Drahoš ◽  
Ján Cigánek ◽  
Roman Leskovský  ◽  
...  

For the development of modern complex production processes in Industry 4.0, it is appropriate to effectively use advanced mathematical models based on Petri nets. Due to their versatility in modeling discrete-event systems, Petri nets are an important support in creating new platforms for digitized production systems. The main aim of the proposed article is to design a new software tool for modeling and control of discrete-event and hybrid systems using Arduino and similar microcontrollers. To accomplish these tasks, a new tool called PN2ARDUINO based on Petri nets is proposed able to communicate with the microcontroller. Communication with the microcontroller is based on the modified Firmata protocol hence, the control algorithm can be implemented on all microcontrollers that support this type of protocol. The developed software tool was successfully verified in control of laboratory systems. In addition, it can be used for education and research purposes as it offers a graphical environment for designing control algorithms for hybrid and mainly discrete-event systems. The proposed software tool can improve education and practice in cyber-physical systems (Industry 4.0).


2017 ◽  
Vol 3 (2) ◽  
pp. 195-198
Author(s):  
Philip Westphal ◽  
Sebastian Hilbert ◽  
Michael Unger ◽  
Claire Chalopin

AbstractPlanning of interventions to treat cardiac arrhythmia requires a 3D patient specific model of the heart. Currently available commercial or free software dedicated to this task have important limitations for routinely use. Automatic algorithms are not robust enough while manual methods are time-consuming. Therefore, the project attempts to develop an optimal software tool. The heart model is generated from preoperative MR data-sets acquired with contrast agent and allows visualisation of damaged cardiac tissue. A requirement in the development of the software tool was the use of semi-automatic functions to be more robust. Once the patient image dataset has been loaded, the user selects a region of interest. Thresholding functions allow selecting the areas of high intensities which correspond to anatomical structures filled with contrast agent, namely cardiac cavities and blood vessels. Thereafter, the target-structure, for example the left ventricle, is coarsely selected by interactively outlining the gross shape. An active contour function adjusts automatically the initial contour to the image content. The result can still be manually improved using fast interaction tools. Finally, possible scar tissue located in the cavity muscle is automatically detected and visualized on the 3D heart model. The model is exported in format which is compatible with interventional devices at hospital. The evaluation of the software tool included two steps. Firstly, a comparison with two free software tools was performed on two image data sets of variable quality. Secondly, six scientists and physicians tested our tool and filled out a questionnaire. The performance of our software tool was visually judged more satisfactory than the free software, especially on the data set of lower quality. Professionals evaluated positively our functionalities regarding time taken, ease of use and quality of results. Improvements would consist in performing the planning based on different MR modalities.


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