Development of a non-linear process control test bench and empirical investigation of control performance

Non-linear systems have been challenging for control engineers since a long time. In this paper a laboratory test bench is presented which can demonstrate a non-linear process. A conical tank is used to depict non-linearity for this study. A conical tank shows non-linearity in its model due to its variation in area with respect to its height. As the level of fluid inside the conical tank varies, time constant and gain of the process will also vary. In this study investigations are performed to check the control performance of the non-linear process at different operating points. LabVIEW is used as computational tool to implement control strategies. In future a low cost embedded system using an Advanced RISC Machine (ARM) based controller will be developed in such a manner that it will perform the computational task and LabVIEW will only be used as a tool to monitor the operation inside the conical tank in real time. The paper includes mathematical modelling, system integration, implementation, results and future scope.