Development of Control Lab Interface for Data Acquisition using Lab VIEW

A lab named ‘System Identification Lab’ is a compulsory part of the course ‘Modeling of Dynamical System’ given by School of Electrical Engineering, Automatic Control at KTH. System identification is an experimental method to derive a mathematical model from the input and the output data. The apparatus used in the lab is a fan and a hinged rectangular plate. Both fan and plate are mounted on aslide. The idea of this lab is to collect the input and output data from this process. The input data is theDC voltage sent to the fan and the output is the angular displacement of the plate due to air stream from the fan. This data is then used to derive a linear model by applying different theoretical methods. The main focus of this thesis work has been to design a user interface for this lab, and implement it in LabVIEW, which is an easy to use, integrated graphical environment with built-in compatibility across a broad range of data acquisition and control hardware devices. In short, the interface first lets the user choose the sampling time and then one can choose between different input signals. The input and output signals are displayed as plots on the screen and can also be saved to a file. A second, similar interface has also been implemented, where the process is replaced by a simulation model. The simulation model is based on an identified linear model with some added disturbances and non-linear effects. The idea with the simulation model is that the ‘System Identification Lab’ then can be done without using the lab process. This report also includes an introduction to system identification and a discussion about how to choose appropriate input signals for an identification experiment. These methods are used to derive the simulation model and in order to understand the lab process better, some step responses are done and the process is also modeled from physical principles