Lars Struen Imsland

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A simple procedure to include state inequality constraints in the unscented Kalman filter is proposed. With this procedure, the information of active state constraints influences the state covariance matrix, resulting in better estimates. In a numerical example, the approach outperforms the extended Kalman filter implemented with constraint handling via(More)
This paper reports on experiences from case studies in using Modelica/Dymola models interfaced to control and optimization software, as process models in real time process control applications. Possible applications of the integrated models are in state-and parameter estimation and nonlinear model predictive control. It was found that this approach is(More)
The principle of state estimation of a dynamic system using Unscented Kalman Filter (UKF) and Extended Kalman Filter (EKF) is briefly described. Two nonlinear examples are considered to compare the state estimation using UKF and EKF. A Solid Oxide Fuel Cell (SOFC) combined with Gas Turbine (GT) hybrid system is described and system level modeling of the(More)
Two recent contributions to the literature (Kouvaritakis et al., 2000; Imsland et al., 2004) have shown how to use offline analysis to reduce online computation while enlarging the feasible regions of a control law. Both methods make use of an augmented system so this paper gives some proper discussion of their differences and similarities and in particular(More)
As production on the Norwegian shelf enters tail production, drilling wells with vanishing pressure windows become more attractive. This motivates use of automatic control systems for improved control of downhole pressure using Managed Pressure Drilling (MPD) techniques. PID SISO control solutions for MPD are by now relatively standard, and well understood.(More)
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