Design and analysis of modified Smith predictors for integrating Processes with longer dead time Using adaptive tuning

Abstract

Time delay occurs frequently in process control problems newlineCompared to processes without delay the presence of delay in processes newlinegreatly complicates the analytical aspects of control system design and makes newlineeffective control more difficult to achieve Delay compensation technique newlinedeveloped by Otto smith is probably the most popular and effective which newlineutilizes a mathematical model of the process in the minor feedback loop newlinearound the conventional controller and has an advantage of eliminating the newlinedelay from the characteristic equation of the closed loop system Thus the newlinedesign problem for the process with delay can be converted to the one without newlinedelay Modification of classical dead time compensating technique for newlinecontrolling the higher order processes with integral action and long dead time newlineis enhanced in this research work PID controllers have been widely used in newlinevarious industries due to their simplicity and reliability Such controllers newlineexhibit poor performance when applied to plants with long time delays The newlinedesign technique in this work using an Integral Proportional Derivative newlinecontroller is utilized to characterize various types of processes such as newlineIntegrator with longer dead time linear plants with time variant and newlineunknown parameters and for non minimum phase processes with integrator newlineand dead time The high closed loop system performances fast setpoint newlineresponse and satisfactory load disturbance rejection can be obtained even in newlinethe presence of unmodeled dynamics It is also proved that there will be no newlinesteady state error for a constant load disturbance newline newline