LabVIEW based Sliding Mode Control of a pH Neutralization System

Abstract

This paper targets at designing a control mechanism using the method of Variable Structure Control [VSC] for a pH neutralization process plant. This VSC involves SLIDING MODE CONTROL (SMC). The prototype pH model involves acidic and alkaline reagent solutions which in proper quantities are mixed into a Continuous Stirred Tank Reactor [CSTR] in proper proportions. The pH of the plant is in turn controlled by the same. The flow rate of acid and alkaline solutions is controlled by the control mechanism. SMC is a type of nonlinear control. The pH neutralization process is a best example of non linear system; hence SMC offers a better solution. SMC suffers a problem called chattering, to overcome this, Dynamic Sliding Mode controller can be implemented. LabVIEW software is used to implement the controller. LabVIEW is the acronym for Laboratory Virtual Instrumentation Workbench. The prototype model is subjected to this programming method and the results are presented. This is a graphical programming technique. The interfacing of the software and the prototype hardware is done using DAQs.