Papers by Vasile Marinescu
The Programmable Logic Controller (PLC) plays a vital role in automation and process control. Gra... more The Programmable Logic Controller (PLC) plays a vital role in automation and process control. Grafcet is used for representing the control logic, and traditional programming languages are used for describing the pure algorithms. Grafcet is used for dividing the process to be automated in elementary sequences that can be easily implemented. Each sequence represent a step that has associated actions programmed using textual or graphical languages after case. The programming task is simplified by using a set of subroutines that are used in several steps. The paper presents an example of implementation for a punching machine for sheets and plates. The use the graphical languages the programming of a complex sequential process is a necessary solution. The state of Grafcet can be used for debugging and malfunction determination. The use of the method combined with a set of knowledge acquisition for process application reduces the downtime of the machine and improve the productivity.
Knowledge, like information, are worthless if not applied in decisions on necessary actions in th... more Knowledge, like information, are worthless if not applied in decisions on necessary actions in the context of economic activity of the company. Many companies have worked hard to store information on available knowledge, but did not give enough attention to the chase how to apply, are used not only actual work but also to generate new ideas for future activity. In today's society can get access a immense volume of information from almost anywhere. But only information is not sufficiently. The feature of knowledge society is not that it has large amounts of information, but inside always it has to know more. To this information to become useful, it must be transformed into knowledge and then used efficiently in company management. What we propose in this paper is to provide manager, based knowledge he has, (economic and technical knowledge) a model of KM (knowledge management) to his enterprise to be competitive. Key-Words: knowledge, knowledge management (KM), knowledge-based ec...
… on Systems and Control, 2008
This paper presents a new programming approach based on a proposed hardware and control architect... more This paper presents a new programming approach based on a proposed hardware and control architecture for the reconfigurable manufacturing tool machine. A new CAM is described based on virtual machining algorithm that optimizes feedrate scheduling based on geometric simulation and aims to improve the efficiency of cutting process developed using a reconfigurable machine, configured as lathe with a specific architecture. A searching procedure is proposed to find the parameter values corresponding to cutter locations along tool path during generation of the final surface.
Citeseer
The Programmable Logic Controller (PLC) plays a vital role in automation and process control. Gra... more The Programmable Logic Controller (PLC) plays a vital role in automation and process control. Grafcet is used for representing the control logic, and traditional programming languages are used for describing the pure algorithms. Grafcet is used for dividing the process to be automated in elementary sequences that can be easily implemented. Each sequence represent a step that has associated actions programmed using textual or graphical languages after case. The programming task is simplified by using a set of subroutines that are used in several steps. The paper presents an example of implementation for a punching machine for sheets and plates. The use the graphical languages the programming of a complex sequential process is a necessary solution. The state of Grafcet can be used for debugging and malfunction determination. The use of the method combined with a set of knowledge acquisition for process application reduces the downtime of the machine and improve the productivity.
Knowledge management (KM) has become an effective way of managing organization’s intellectual cap... more Knowledge management (KM) has become an effective way of managing organization’s intellectual capital or, in other words, organization’s full experience, skills and knowledge that is relevant for more effective performance in future. The paper proposes a knowledge management to achieve a competitive control of the machining systems. Then an application of Knowledge Management in engineering has been attempted to explain. The model can be used by the manager for the choosing of competitive orders. Key-Words: knowledge management, mechanical engineering, information technology, machining system, marketing knowledge, competitive management.
During machining process, the cutting conditions must be permanent adjusted according to real all... more During machining process, the cutting conditions must be permanent adjusted according to real allowance, surface shape, and machining system local characteristics, in order to obtain high efficiency in every moment of the process running. This problem can be address by high resolution process scheduling. When blank, tool and machining system characteristics accounts deviations comparing with the previous considered values, based on which scheduling was made, it is necessary the scheduling updating according to this deviations. This lead to idea of developing a machining process control system based on online reactive scheduling. In this paper it is presented a control method based on reactive scheduling as well as its application in the case of reconfigurable machine tools, numerically controlled. The main idea is that a parametric software model of the machining cycle is build. By process monitoring, the actual values of the model parameters are online evaluated. If these values di...
Batch manufacturing is a widely used technique in today economy. The conceptual change of the way... more Batch manufacturing is a widely used technique in today economy. The conceptual change of the way in which the manufacturing machines are controlled is the most important aspect in which is possible to conform with the market demands so their reconfigurability would not affect competitiveness. The problem to be solved in this paper consists in a control method development for predictive control based on prediction of the controlled variables deviation values in respect with their programmed values. The basic idea is to use the data set obtained by monitoring the process during the manufacturing of the previous workpieces and during the current workpiece in order to predict the controlled variable value. The method proposed consists in determining of the causal relation between one controlled variable and the monitored variables and then predicting its value in order to compensate the deviation from the program.
Sheet metal stamping is an important manufacturing process because of its high speed and low cost... more Sheet metal stamping is an important manufacturing process because of its high speed and low cost for mass production. To control the flow of the material into the die cavity is crucial to good part quality and consistency. Different solutions are developed in this field during the time but all this are based on the geometrical criteria and can be applied for particular shape of the parts. A fundamental understanding of the relationships between process inputs (such as the sheet, the tools, sheet/tools interfaces, equipment) and process output (product) is extremely important. In this study, an adaptive reduced order modelling based on response of objective was suggested for solving practical engineering problems.
WSEAS Transactions on Systems and Control archive, 2008
Batch manufacturing is a widely used technique in today economy. The conceptual change of the way... more Batch manufacturing is a widely used technique in today economy. The conceptual change of the way in which the manufacturing machines are controlled is the most important aspect in which is possible to conform with the market demands so their reconfigurability would not affect competitiveness. The problem to be solved in this paper consists in a control method development for predictive control based on prediction of the controlled variables deviation values in respect with their programmed values and also to predict the process parameters for which chatter will appear. The basic idea is to use the data set obtained by monitoring the process during the manufacturing of the previous workpieces and during the current workpiece in order to predict the controlled variable value and to train a clasiffier algorithm. The method proposed consists in determining of the causal relation between one controlled variable and the monitored variables and then predicting its value in order to compen...
There are many situations when, to solve a problem connected to machining processes, models of th... more There are many situations when, to solve a problem connected to machining processes, models of thermal or mechanical fields involved by the cutting process are required; because they are multidimensional fields, an appropriate mathematical tool to be used is required. The analytical approach of B-spline functions presents a number of disadvantages related to the great volume of calculations and, it also does not easily allow passing toward multivariable B-spline functions. The use of tensor fields, by means of the tensor product and the contraction products, enables a natural transition from B-spline functions of one variable to multivariable B-spline functions, acquiring some useful functional minimizations in practical applications. The assessment of the value of a multivariable B-spline function, which comes from the tensor product of B-spline functions of one variable, assumes the recurrence of the same calculation algorithm in each coordinate direction, for each B-spline functi...
The optimal feedrate scheduling is an important issue so far that concern machine tool performanc... more The optimal feedrate scheduling is an important issue so far that concern machine tool performance. Moreover, taking into account the unavoidable variation of detached material thickness the process performance can be increased through online high-resolution optimal feedrate scheduling. Such an approach implies the need for considerable software processing resources. In order to solve this problem, the holonic concept, which is part of distributed artificial intelligence field, is applied for feedrate scheduling. In this paper a specific holonic architecture and algorithm is proposed. The basic structural entity of the holonic architecture is the holon, which is an operating system process acting autonomous and cooperative. By intermediary of the holons actions, according to the holonic algorithm, suitable positioning of cutter edge is obtained. On the other hand, each holon represents an interpolated cutter location. The process sequence between two successive interpolated cutter l...
Among the manufacturing operations required to be realized into the ship building domain, stern t... more Among the manufacturing operations required to be realized into the ship building domain, stern tube bushes machining is one of the most important, because it has a high influence onto the good functioning of the ship propulsion system in time. Problems may appear because we are talking about pieces with very large dimensions, which are adjusted after their assembly by welding on the ship hull; additional errors may occur during or after machining, caused by ship body thermal or mechanical induced deformations. In this paper, we try to find an appropriate model for these errors, in order to be able, then, to realize an on-line adaptive control system of the cutting process, which will enable a superior precision of stern tube bushes machining process.
Our paper objective is to propose a new concept of holonic control applied to reconfigurable mach... more Our paper objective is to propose a new concept of holonic control applied to reconfigurable machines. The research aims by holonic approach of reconfigurable manufacturing system to obtain radically new, self-adaptive, rapidly reconfigurable, holonic machines for batch industrial production in open-ended and rapid changing real-market environments. The holonic concept can be applied on both hardware and software levels. The generic holon is defined as a computational entity or a computational entity associated with a physical part. In the paper is show an example of how holonic approach can be implemented by developing the next generation of manufacturing machines.
This paper presents a virtual machining algorithm that optimizes federate scheduling aiming to im... more This paper presents a virtual machining algorithm that optimizes federate scheduling aiming to improve the efficiency of cutting process. The manufacturing machine considered is a reconfigurable machine, configured as lathe with a specific architecture. A geometric searching procedure is proposed to find the parameter values corresponding to cutter locations along tool path during generation of the final surface.
The Programmable Logic Controller (PLC) plays a vital role in automation and process control. Gra... more The Programmable Logic Controller (PLC) plays a vital role in automation and process control. Grafcet is used for representing the control logic, and traditional programming languages are used for describing the pure algorithms. Grafcet is used for dividing the process to be automated in elementary sequences that can be easily implemented. Each sequence represent a step that has associated actions programmed using textual or graphical languages after case. The programming task is simplified by using a set of subroutines that are used in several steps. The paper presents an example of implementation for a punching machine for sheets and plates. The use the graphical languages the programming of a complex sequential process is a necessary solution. The state of Grafcet can be used for debugging and malfunction determination. The use of the method combined with a set of knowledge acquisition for process application reduces the downtime of the machine and improve the productivity. Keywo...
Nowadays techniques for online controlling the cutting process stability are based on the use of ... more Nowadays techniques for online controlling the cutting process stability are based on the use of a sensor, in order to identify the occurrence of self-excited relative vibration between tool and part. A disadvantage of these techniques is that dynamic stability control system reacts only after passing over the stability limit, and the self-excited vibrations have already appeared. Hence, any reaction to the instability occurrence is delayed. This paper presents a novel technique for dynamic stability online control in cutting processes. According to it, the current operating point of the machining system is not only permanently brought into the stability domain, for maintaining the process stable, but also kept near the stability limit, for reaching the maximum level of productivity. The new technique has the following advantages: (i) provides to permanently use the entire processing capacity of the machining system, in optimal terms of dynamic stability; (ii) in the designing stage...
This paper presents a new programming approach based on a proposed hardware and control architect... more This paper presents a new programming approach based on a proposed hardware and control architecture for the reconfigurable manufacturing tool machine. A new CAM is described based on virtual machining algorithm that optimizes feedrate scheduling based on geometric simulation and aims to improve the efficiency of cutting process developed using a reconfigurable machine, configured as lathe with a specific architecture. A searching procedure is proposed to find the parameter values corresponding to cutter locations along tool path during generation of the final surface.
This paper presents an image processing procedure to detect and measure the insert and blade hold... more This paper presents an image processing procedure to detect and measure the insert and blade holder profiles and positions. A holonic approach is considered in this paper whereby objects identification in the scene is performed by basic regions (color based identification) merging in wider regions to meet geometrical description. Specifying relationships between the image components and formulating queries that search for objects, their other associated characteristics, is performed by a language for this specific problem. The proposed method is shown to be effective and suitable for the unmanned measurement of insert and blade holder online identification. Moreover, the proposed approach has the potential to deal with scene object identification problems.
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In machining, the workpiece fixturing is an essential task which often affects the quality of the... more In machining, the workpiece fixturing is an essential task which often affects the quality of the final product. The actual approach of the fixturing error control is based on the correlation of the workpiece position with respect to the tool position and tool programmed trajectory. In this paper, a method for fixturing errors identification is proposed. This method is using input data which consist in the coordinates of points belonging to the reference surfaces. Using on-machine measuring system this input data is acquired and the position parameters of the references surfaces are determined. Data obtained from identification can be used for compensation of the fixturing errors. As a case study, a longitudinal turning process was considered. For the validation of the proposed method a numerical simulation program was conducted.
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Papers by Vasile Marinescu