Performance index for closed-loop controls
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Control performance assessment is becoming increasingly important, as processes are wanted to be as efficient as possible. Performance assessment measures can indicate how well the controllers are functioning, and what can be done to improve their performance. They can be used as an aid in tuning the controller, as well as to monitor the control performance during process operation. The aim of this thesis is to present methods developed for control performance assessment, and evaluate the usability of these methods in assessing the performance of marine engine controls. After presenting the theory, a method to assess the engine control performance is developed. The factors needed to be taken into account regarding the specific processes are discussed. The developed algorithms are then evaluated first with a basic process model and PID control function. Once the functionality is tested, the methods are evaluated with an engine model. Finally, the performance assessment methods are evaluated on an actual engine. Their usability and limitations are discussed, and further actions to be taken are presented. This thesis provides an overview on the present performance assessment methods avail-able, discusses their practical implementation, and their usefulness in marine engine control performance evaluation. However, it is only a start to developing a functioning engine control performance assessment tool. Further developing is still needed. More tests on the actual engine process controls need to be done, to verify the functionality of the methods in different situations. Also, a simplified result from the performance assessment tool should be provided to have one clear value to indicate the whole engine control performance.