Identification and real time control of a hybrid tank system through virtual instrumentation

Modeling of level process in various tanks and vessels is one of the most common problems in the process industry. In this paper, system identification process is attempted for hybrid tank process. The hybrid tank process is a classic example of a highly nonlinear system. For nonlinear systems, System identification provides a better alternative to find their system transfer function. First principle modeling of level process is done with so much of assumption. System identification procedure gives accurate model. Inflow rate is taken as the input data and process level is taken as the output for hybrid tank. The input flow is measured using a turbine flow meter while the output level is measured using a differential pressure transmitter (DPT). Collected data is fitted to transfer function model set. The simulation is performed in the MATLAB environment using System Identification codes and model reference adaptive control toolbox. We have found practically the model of the hybrid tank using the MATLAB environment which gives the results almost identical to the ideal model of the plant. The system identification process is used here to identify the nature of the system using the inputs and the outputs available. After this identification process best model can be chosen and then model reference adaptive controller is implemented in simulation and PI, PID controllers are implemented in real-time to check the charateristics of the hybrid tank system.