Variable Structure Control Approach For Non linear Systems

Abstract

Due to the advancement in communication technology and simulation software, the development of model based controllers are becoming more and more popular. The process industry uses the conventional controllers which are easy to implement and performs efficiently. This is true when we do not consider the undesirable condition or uncertainty. Often in the undesirable situation these conventional methods fail to perform. So the effort has been made to use the model based robust controllers to the process control application. The robust controller of the variable structure systems type i.e. the sliding mode control is used to control the process parameters, level and temperature that are widely used in any chemical process. A coupled tank system and the highly non-linear model of batch reactor is considered. The results for the conventional first order sliding mode control are plotted in the presence of sine type of matched disturbance. The chattering is observed in the control law. The means to reduce the chattering has been adopted by using the modified reaching law i.e. power rate reaching law. Further, higher order sliding mode type super twisting controller is implemented on the both the systems. To observe the real time behaviour of the control algorithms, a constant volume stirred reactor is considered whose temperature is to be controlled. The results of power rate reaching law and the super twisting controller are plotted and observed for supressed chattering in the MATLAB Simulink newline newline