Injection velocity during filling stage was experimentally controlled using different control algorithms, from simple open-loop control and Proportional-Integral (PI) closed-loop control, to more advanced strategies such as Self-Tuning Regulator (STR), fuzzy control and Generalized Predictive Control (GPC). It is shown that the advanced control can effectively overcome the nonlinear and time-varying characteristics of the filling velocity. The advantages and drawbacks of each strategy are presented and experimentally illustrated. The use of advanced control strategies is shown to be necessary for accurate control of the injection velocity with good repeatability.
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