Implementing machine-directional basis weight control for a pilot paper machine

The model of a paper machine is very complex and difficult to describe completely by a mathematical model. There are a lot of parameters in both the wet and dry end of the machine and there is a very large time delay in the system which effects the quality of the paper being produced. Although the PID controller is widely used for these types of applications, it is often not tuned very well. In this work, a newly developed algorithm (Munro, The systematic design of PID controllers, IEE Colloquium in Robust Control: Theory, Software and Applications, Austin Court, Birmingham, 1999) is used for tuning the PID controller. Along with this controller, a Smith-predictive controller is applied to the plant and the transient and steady-state behaviours of these controllers are compared. Hardware and software implementations of the closed-loop control are also presented in the paper.