Controller Design based on Desired Phase Margin for Headbox Process

Paper machine headbox is a highly nonlinear and interacting 2 inputs - 2 outputs multivariable system. Headbox is the major subsystem of paper machine. Since the quality of paper produced is majorly dependent on efficient operation of headbox. So its precise control is extremely essential. A method of PID tuning for paper machine headbox pressure has been presented in this paper. The tuning technique is based on Bode's Integral Method (BIM) wherein the response is calculated at certain specific phase margins. A comparison of responses and performance indices at different phase margins has been presented.