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11 – 20 of over 235000Jakob Stoustrup, M.J. Grimble and Henrik Niemann
Considers control systems operating under potentially faulty conditions. Discusses the problem of designing a single unit which not only handles the required control action but…
Abstract
Considers control systems operating under potentially faulty conditions. Discusses the problem of designing a single unit which not only handles the required control action but also identifies faults occurring in actuators and sensors. In common practice, units for control and for diagnosis are designed separately. Attempts to identify situations in which this is a reasonable approach and cases in which the design of each unit should take the other into consideration. Presents a complete characterization for each case and gives systematic design procedures for both the integrated and non‐integrated design of control and diagnosis units. Shows how a combined module for control and diagnosis can be designed which is able to follow references and reject disturbances robustly, control the system so that undetected faults do not have disastrous effects, reduce the number of false alarms and identify which faults have occurred.
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Brett Parnell, Merlin Stone and Eleni Aravopoulou
This paper aims to explore the problems of managing superprojects and identifies how a different approach to controlling them can reduce the incidence of cost and time overruns…
Abstract
Purpose
This paper aims to explore the problems of managing superprojects and identifies how a different approach to controlling them can reduce the incidence of cost and time overruns and benefit shortfalls.
Design/methodology/approach
Literature review accompanied by conceptual analysis.
Findings
Project cost and timing overruns and benefit shortfalls are very frequent in superprojects. These problems can be ascribed partly to the way in which they are planned is not taken into account in designing and implementing control systems, particularly the governance processes and the information they have available.
Practical implications
This paper has serious implications for those designing control processes, governance and information management for superprojects. It suggests that if a new approach is taken, fewer superprojects will suffer from cost overruns and benefit shortfalls because remedial actions will be taken earlier for projects, which are experiencing problems, while learning will be fed back to those planning new projects.
Social implications
There will be saving of public money and reduced deferment of benefits that normally result from failed or delayed projects and reduced allocation of large incremental budgets dedicated to resolving problems.
Originality/value
The taxonomy of different types of superprojects is original, as is the idea of ambidextrous control, and the diagnosis of failure reasons lying in the nature of control and governance processes, and the lack of relevant information available during the control process.
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Yajing Gu, Hongyan Yan and Yuanguo Zhu
The purpose of this paper is to propose an iterative Legendre technique to deal with a continuous optimal control problem (OCP).
Abstract
Purpose
The purpose of this paper is to propose an iterative Legendre technique to deal with a continuous optimal control problem (OCP).
Design/methodology/approach
For the system in the considered problem, the control variable is a function of the state variables and their derivatives. State variables in the problem are approximated by Legendre expansions as functions of time t. A constant matrix is given to express the derivatives of state variables. Therefore, control variables can be described as functions of time t. After that, the OCP is converted to an unconstrained optimization problem whose decision variables are the unknown coefficients in the Legendre expansions.
Findings
The convergence of the proposed algorithm is proved. Experimental results, which contain the controlled Duffing oscillator problem demonstrate that the proposed technique is faster than existing methods.
Originality/value
Experimental results, which contained the controlled Duffing oscillator problem demonstrate that the proposed technique can be faster while securing exactness.
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Igor Patlashenko and Dan Givoli
The optimal control of the steady‐state temperature distribution in radiating panels using control heat sources is considered. The problem has important applications in the…
Abstract
The optimal control of the steady‐state temperature distribution in radiating panels using control heat sources is considered. The problem has important applications in the thermal control of space structures. A mathematical model leads to an elliptic nonlinear optimal control problem. A numerical optimal control method, based on finite element (FE) discretization and sequential quadratic programming (SQP), is employed. Results are presented for some specific examples.
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Abdykappar Ashimov and Yuriy V. Borovskiy
The purpose of this paper is to demonstrate an effectiveness of applying a number of the new methods, proposed in the parametric control theory for testing macroeconomic models…
Abstract
Purpose
The purpose of this paper is to demonstrate an effectiveness of applying a number of the new methods, proposed in the parametric control theory for testing macroeconomic models for the possibility of their practical application.
Design/methodology/approach
Approaches of system analysis on building and calibrating the mathematical models; provisions of the parametric control theory for both numerical testing of the calibrated models for the possibility of their practical application and solving the parametric control problems.
Findings
First, one global computable general equilibrium model (CGE model) is built and calibrated. Second, in solving the problem of testing this model for the possibility of its practical application the effectiveness of applying two developed numerical algorithms is demonstrated. These algorithms are for estimating stability indicators and estimating stability (in the sense of the theory of smooth mappings stability) of mappings defined by the model. Third, on the base of the tested CGE model there are given the solution results for a number of the parametric control problems aimed at economic growth and decrease of economic disparities of regions.
Originality/value
By the example of the developed CGE model, it is demonstrated an approach of the parametric control theory for testing macroeconomic models for the possibility of their practical application.
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The most basic solution for monitoring position and attitude of an UA is through direct line-of-sight. Because they are usually standing outside, a pilot that maintains direct…
Abstract
The most basic solution for monitoring position and attitude of an UA is through direct line-of-sight. Because they are usually standing outside, a pilot that maintains direct line-of-sight with the aircraft is usually referred to as the EP, as opposed to an internal pilot (IP) who obtains position and attitude information electronically while inside of a ground control station (GCS). Flight using an EP represents the most basic solution to the problem of separating the pilot from the aircraft while still enabling the pilot to monitor the location and attitude of the aircraft. Pilot perspective is changed from an egocentric to an exocentric point of view. Maintaining visual contact with the UA, the EP can control the aircraft using a hand-held radio control box. Many of these control boxes are similar to those used by radio-controlled aircraft hobbyists and provide direct control of the flight surfaces of the aircraft through the use of joysticks on the box. Very little automation is involved in the use of such boxes, which control the flight surfaces of the aircraft.
Satisfying target markets is a major strategic purpose of all organisations. Logistics management, however, often encounters difficulty in serving individual customer groups. The…
Abstract
Satisfying target markets is a major strategic purpose of all organisations. Logistics management, however, often encounters difficulty in serving individual customer groups. The target market or market segment is the building block of corporate strategy, the focus of both marketing and logistics efforts. Marketing focuses narrowly on specific sets of customers who respond in a similar way to the marketing mix. Logistics strategy, on the other hand, stresses the integration of material and product flow through the organisation as a single unit. The common bond lies in meeting the needs of these groups.
Ezzeddine Touti, Ali Sghaier Tlili and Muhannad Almutiry
This paper aims to focus on the design of a decentralized observation and control method for a class of large-scale systems characterized by nonlinear interconnected functions…
Abstract
Purpose
This paper aims to focus on the design of a decentralized observation and control method for a class of large-scale systems characterized by nonlinear interconnected functions that are assumed to be uncertain but quadratically bounded.
Design/methodology/approach
Sufficient conditions, under which the designed control scheme can achieve the asymptotic stabilization of the augmented system, are developed within the Lyapunov theory in the framework of linear matrix inequalities (LMIs).
Findings
The derived LMIs are formulated under the form of an optimization problem whose resolution allows the concurrent computation of the decentralized control and observation gains and the maximization of the nonlinearity coverage tolerated by the system without becoming unstable. The reliable performances of the designed control scheme, compared to a distinguished decentralized guaranteed cost control strategy issued from the literature, are demonstrated by numerical simulations on an extensive application of a three-generator infinite bus power system.
Originality/value
The developed optimization problem subject to LMI constraints is efficiently solved by a one-step procedure to analyze the asymptotic stability and to synthesize all the control and observation parameters. Therefore, such a procedure enables to cope with the conservatism and suboptimal solutions procreated by optimization problems based on iterative algorithms with multi-step procedures usually used in the problem of dynamic output feedback decentralized control of nonlinear interconnected systems.
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