• A New Static Estimator Based on Self-Optimizing Theory 

      Grimholt, Chriss (Master thesis, 2011)
      This thesis compares the performance of the new static model based esti- mator proposed by Skogestad et al. (2011) with least squares (LS), principal component regression (PCR), and partial least squares (PLS) estimators ...
    • Biodiesel Production by the Esterfip-H Process: Modelling, Optimization and Control Structure 

      Øien, Marianne (Master thesis, 2013)
      For this master's thesis the Esterfip-H process for biodiesel production from rapeseed oil have been modelled in Chemcad. Esterfip-H is a two fixed-bed reactor system using a heterogeneous catalyst of zinc aluminate oxide ...
    • Optimal PI and PID control of first-order plus delay processes and evaluation of the original and improved SIMC rules 

      Grimholt, Chriss; Skogestad, Sigurd (Journal article; Peer reviewed, 2018)
      The first-order plus delay process model with parameters k (gain), τ (time constant) and θ (delay) is the most used representation of process dynamics. This paper has three objectives. First, we derive optimal PI- and ...
    • Optimal Temperature Control of Rooms for Minimum Energy Cost 

      Trapnes, Siri Hofstad (Master thesis, 2013)
      In this thesis was a room with direct heating in the floor and room modelled. The aim has been to minimize the energy cost of the room, assuming that the future energy price and weather forecast is known. The constrained ...
    • Optimal tuning of PID controllers: And the verification of the SIMC rules 

      Grimholt, Chriss (Doctoral theses at NTNU;2018:389, Doctoral thesis, 2018)
      Optimal tuning of PID controllers and the verification of the SIMC rules The simple PI/PID controller is the most used controller in the process industry. However, finding good settings for this simple controller is not ...
    • Optimization of fixed-order controllers using exact gradients 

      Grimholt, Chriss; Skogestad, Sigurd (Journal article; Peer reviewed, 2018)
      Finding good controller settings that satisfy complex design criteria is not trivial. This is also the case for simple fixed-order controllers including the three parameter pid controller. To be rigorous, we formulate the ...
    • Performance and Robustness of Smith Predictor Control and Comparison with PID Control 

      Holene, Axel Lødemel (Master thesis, 2013)
      The performance and robustness of the Smith predictor controller has been tested for first and second order processes with time-delay by comparing with PI and PID control. It was assumed that the performance would obviously ...
    • Reactive Distillation of Biodiesel: Modelling and Optimal Operation 

      Houge, Emilie Oritsland (Master thesis, 2013)
      This thesis modifies an already existing dynamic Matlab Simulink model to correlate with a Hysys model from a similar research. The models are concerned with the reactive distillation for production of biodiesel from ...
    • Reactive Distillation of Biodiesel: Modelling and Optimal Operation 

      Houge, Emilie Øritsland (Master thesis, 2013)
      This thesis modifies an already existing dynamic Matlab Simulink model to correlate with a Hysys model from a similar research. The models are concerned with the reactive distillation for production of biodiesel from ...
    • Should we forget the Smith Predictor? 

      Grimholt, Chriss; Skogestad, Sigurd (Journal article; Peer reviewed, 2019)
      The PI/PID controller is the most used controller in industry. However, for processes with large time delays, the common belief is that PI and PID controllers have sluggish performance, and that a Smith predictor or similar ...
    • Simple Well-Model Based on Basic Physical Principles 

      Duus, Ane Cecilie (Master thesis, 2013)
      To reduce loss, real-time optimization (RTO) is today used in most petroleum industry. Minimizing loss is achieved by avoiding over- or underutilization of the production system, and keeping the process as close to the ...