W. Grega - Academia.edu (original) (raw)

Papers by W. Grega

Journal of Automation, Mobile Robotics and Intelligent Systems, 2009

Przegląd Elektrotechniczny, 2009

IFAC Proceedings Volumes, 1989

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Accurate control of liquid levels in chemical and metallurgical industry is a key factor in impro... more Accurate control of liquid levels in chemical and metallurgical industry is a key factor in improving the quality of the product. This paper describes a control method applicable to the cascade of tanks with nonlinear dynamics. The approach is based both on decomposition and feedback linearization. The control law proposed in the paper not only stabilises levels in the tanks but also prevents saturation of the levels. The methodology described in the paper was successfully applied to a laboratory two-tank configuration controlled in real-time.

International Journal of Modeling and Optimization, 2015

Improvement of process efficiency and product quality is available through implementation of more... more Improvement of process efficiency and product quality is available through implementation of more complex control algorithms and more accurate process models. It is especially critical for the glass industry production chain since glass production is a complex processes with high energy usage. The accuracy and robustness of advanced control algorithms is strictly dependent on the quality of the underlying mathematical model of the production process. This paper presents the formalisation and an empirical investigation of the hypothesis that a simplified, Finite Element Method (FEM)-based model can capture the closed-loop process dynamics over longer time scales and is suitable for real-time applications. The paper demonstrates how a tradeoff between model complexity and simulation time can be found.

Pomiary Automatyka Robotyka, 2014

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The principle of the energy saving algorithm in buildings is based on lowering the night-time tem... more The principle of the energy saving algorithm in buildings is based on lowering the night-time temperature and increasing (preheating) it in the morning. One important problem of this strategy consists in keeping peek demand of energy below the maximum power of the central energy source. A model-reference nonlinear predictive control algorithm is studied and the effects of peak power demand reduction are compared with linear control method. Stability of the predictive control system is analyzed.

2014 19th International Conference on Methods and Models in Automation and Robotics (MMAR), 2014

The paper studies the control of networked control systems (NCS) with sensor-to-controller and co... more The paper studies the control of networked control systems (NCS) with sensor-to-controller and controller-to-actuator time delays. The delays are bigger than one sample and random. By using of buffers, the original problem can be transformed into linear system with constant delay. The optimal size of the buffer is an open problem. Increase of the buffer length deteriorates the quality because of longer delay in the control loop. At the same time longer buffer decreases the probability of packet dropping and thus improves the quality. The idea is to make the system more robust by buffering and simultaneously adjusting the control loop sampling and actuation intervals. The paper presents this “co-design” approach and demonstrates it for LQ control problem of cart-pendulum model.

Proceedings of IEEE International Conference on Control and Applications CCA-94, 1994

In this paper it is shown that, given a nonlinear, multivariable minimum-time control problem, it... more In this paper it is shown that, given a nonlinear, multivariable minimum-time control problem, it is possible to apply in real-time the simulation model in order to modify parameters of the feedback controller. As an application the control of the coupled tank system is presented

Zeszyty Naukowe. Mechanika, 2001

Streszczenie angielskie: Prototyping methods of control algorithms in an open and integrated envi... more Streszczenie angielskie: Prototyping methods of control algorithms in an open and integrated environment are shown for a 3D crane laboratory model. Streszczenie polskie: Na przykladzie sterowania suwnicą ramową przedstawiono metody prototypowania ...

Automatica, 1993

This paper presents a new approach for solving timetable optimization problems. The original prob... more This paper presents a new approach for solving timetable optimization problems. The original problem is decomposed into subproblems along the discrete time axis. For each subproblem the motion of vehicles is described by treating headways between them as the state variables. The layover times at the terminals are considered as the decision variables. This model allows the implementation of optimal control theory with quadratic criterion and technical constraints imposed on the state and control. The problem is to obtain after a fixed number of trips a desired configuration of headways and to "glue" partial timetables together creating the final timetable. A numerical example is given to illustrate the idea.