Reduced-order estimator for closed-loop online estimation of cross-directional parameters in a plastics extrusion process

The paper addresses the problem of estimating the “effective” actuator centre locations in a plastics extrusion process while the process is operating in closed loop. It shows that it is possible to use a lower-order model estimator and hence considerably reduce the complexity of the procedure. The estimator is described as a radial basis function network, where the basis functions in the hidden layer are defined using discrete Chebyshev polynomials. The problem is considered as a nonlinear optimisation problem and solved online using a recursive prediction error method