Search results for " control system"
showing 10 items of 262 documents
Linkages between the Elements of Management Control Systems in a Non-Profit Organization
2011
This qualitative case study examines the emergence of MCS package. We apply the MCS package framework of [Malmi, T. and Brown, D.A. (2008) Management control systems as a package-Opportunities, challenges and research directions, Management Accounting Research, Vol. 19, Iss. 4, pp. 287-300] and investigate the linkages between different control elements of MCS package. The control elements of MCS package, particularly governance structures and cybernetic systems became often overlapping and redundant. All the control elements remained in the MCS package when they were once constructed. Even tough a large number of cybernetic controls (i.e. balanced scorecard, budgets, quality management sys…
DSC: software tool for simulation-based design of control strategies applied to wastewater treatment plants.
2011
This paper presents a computer tool called DSC (Simulation based Controllers Design) that enables an easy design of control systems and strategies applied to wastewater treatment plants. Although the control systems are developed and evaluated by simulation, this tool aims to facilitate the direct implementation of the designed control system to the PC of the full-scale WWTP (wastewater treatment plants). The designed control system can be programmed in a dedicated control application and can be connected to either the simulation software or the SCADA of the plant. To this end, the developed DSC incorporates an OPC server (OLE for process control) which facilitates an open-standard communic…
Multi-rate PID Controller for a Networked Control System
2007
In networked control systems several devices (controller, process and others) share a common communication bus. This feature can suppose delays when those devices try to transmit information through the unique bus, leading to a non- regular behaviour, that is, different variables are sampled and updated in a non-uniform way along the time. As a result, if the control system is designed by means of classical design techniques, control performance can be degraded, since these techniques used not to consider those delays. In order to undertake this problem, a solution based on a PID controller's parameters readjustment is proposed. This approach permits to retune these parameters depending on …
Experimental investigation on high efficiency real-time control algorithms for IPMSMs
2014
This paper describes an experimental investigation on the power losses variations occurring in an Interior Permanent Magnet Synchronous Motor (IPMSM) with respect to the direct axis current component. Such investigation can be useful to determine a mathematical model accounting for copper, iron and mechanical friction losses, and for the arrangement of a speed control drive system equipped with a real-time power losses minimization algorithm. In particular, a test bench has been set up in order to carry out all measurements and the final power loss identification. The test bed is composed by a IPMSM drive with a field oriented control (FOC) strategy, a power analyzer, a dynamometric brake a…
Time reduction for completion of a civil engineering construction using fuzzy clustering techniques
2017
In the civil engineering field, there are usually unexpected troubles that can cause delays during execution. This situation involves numerous variables (resource number, execution time, costs, working area availability, etc.), mutually dependent, that complicate the definition of the problem analytical model and the related resolution. Consequently, the decision-maker may avoid rational methods to define the activities that could be conveniently modified, relying only on his personal experience or experts’ advices. In order to improve this kind of decision from an objective point of view, the authors analysed the operation correction using a data mining technique, called Fuzzy Clustering. …
Hierarchical control with virtual resistance optimization for efficiency enhancement and State-of-Charge balancing in DC microgrids
2015
This paper proposes a hierarchical control scheme which applies optimization method into DC microgrids in order to improve the system overall efficiency while considering the State-of-Charge (SoC) balancing at the same time. Primary droop controller, secondary voltage restoration controller and tertiary optimization tool formulate the complete hierarchical control system. Virtual resistances are taken as the decision variables for achieving the objective. simulation results are presented to verify the proposed approach.
Integrating Manufacturing Equipments Using a Shop Floor Control System
2006
A generic manufacturing system must interact with an environment characterized by a strong competition and by continuous technological changes. For this reason there is the necessity to make the system easily and economically modifiable in its hardware and software configuration. One of the main problems in making a manufacturing system re-configurable concerns its control system which has to be accordingly scalable and object oriented. This paper presents a methodology for making a manufacturing control system actually reconfigurable and adaptable to hardware changes in the manufacturing systems components. In particular, a PC-based shop-floor control system has been realized. Such system …
A polynomial algorithm solving a special class of hybrid optimal control problems
2006
Hybrid optimal control problems are, in general, difficult to solve. A current research goal is to isolate those problems that lead to tractable solutions [5]. In this paper, we identify a special class of hybrid optimal control problems which are easy to solve. We do this by using a paradigm borrowed from the Operations Research field. As main result, we present a solution algorithm that converges to the exact solution in polynomial time. Our approach consists in approximating the hybrid optimal control problem via an integer-linear programming reformulation. The integer-linear programming problem is a Set-covering one with a totally unimodular constraint matrix and therefore solving the S…
A Fuzzy Discrete Event Simulator for Fuzzy Production Environment Analysis
1998
Abstract Discrete Event Simulation is a powerful tool to help production managers in planning manufacturing systems. The necessity to rapid react to market conditions is pushing production planners to process requirements and information affected by vagueness. Vagueness is related with event definition, therefore it is not manageable through statistical tools, but more properly by using fuzzy mathematics. Production situations where uncertainty takes body in term of vagueness are referred as Fuzzy Production Environments. Classical Discrete Event simulators are not suitable to deal with fuzzy variables, therefore they cannot be used to model Fuzzy Production Environments. This paper aims to…
Feasibility issues in static output-feedback controller design with application to structural vibration control
2014
Recent results in output-feedback controller design make possible an efficient computation of static output-feedback controllers by solving a single-step LMI optimization problem. This new design strategy is based on a simple transformation of variables, and it has been applied in the field of vibration control of large structures with positive results. There are, however, some feasibility problems that can compromise the effectiveness and applicability of the new approach. In this paper, we present some relevant properties of the variable transformations that allow devising an effective procedure to deal with these feasibility issues. The proposed procedure is applied in designing a static…