Browsing by Author "Pandelidis, I.O."
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Item Injection Molding Process Control - A Review.(1986) Agrawal, Rakesh; Pandelidis, I.O.; Pecht, M.; ISRThis paper reviews control strategies employed in the injection molding process. For clarity, the controlled variables have been categorized into all phase control, phase-dependent control and cycle to cycle control. All phase control includes variables which must be monitored and controlled at all times i.e. in all the phases. Control of variables which are triggered during a specific phase are discussed under phase dependent control. In cycle to cycle control, use is made of the previous data in order to predict future trends and take corrective actions thereof. The cyclic, dynamic and unsteady state nature of the injection molding process has been discussed with respect to the conventional PI and PID controllers as well as the more advanced control schemes such as self-tuning control, optimal control, and statistical process control. Suggestions involving specific advanced control schemes and recommendations for-future research in injection molding process control have also been made.Item Observers for Optimal Anticipatory Control of Ram Velocity in Injection Molding.(1986) Agrawal, Rakesh; Pandelidis, I.O.; ISRThe application of optimal anticipatory control assumes that the entire state is available for feedback. However, in the case of injection molding this assumption is violated due to economic considerations. For that purpose, this paper discusses the effectiveness of optimal anticipatory control using estimates of the states obtained from a dynamic system, called observer. State estimation is essential to optimal control techniques since in general the states are used in some form of feedback and the number of measurable states is usually much less than the actual number of state variables, limited by the availability of cheap and rugged sensors and the ease of installation. Furthermore the measurements from the existing sensors may be corrupted by significant noise. In the present paper both the stochastic and the deterministic cases are investigated for application to optimal control of ram velocity in injection molding.Item Optimal Anticipafory Control of Ram Velocity in Injection Molding.(1986) Pandelidis, I.O.; Agrawal, Rakesh; ISRThis paper discusses a computer control system for ram velocity of an injection molding machine using optimal state feedback based on the linear quadratlc control theory. A new approach for the selection of appropriate weighting matrices is presented in this context. The simulation results reveal that the optimal controller has improved performance over the conventional PID controller presently used, having faster speed of response, significantly better and the core storage requirements would allow implementation even on a small online computer.