On the use of SPSA-based model-free controller in quality improvement

There exists a growing realization that quality will be gained by implementing statistical process control and engineering process control in a complementary fashion. This study continues in that direction by considering the batch polymerization example of Vander Wiel et al. (1992), but it assumes no knowledge about the dynamics of process. It uses concurrently the special cause control chart and the simultaneous perturbation stochastic approximation based control approach proposed by Spall and Cristion (1992, 1994) to monitor, signal and readjust the levels of viscosity of simulated batches of polymer around the target value