Ejector controller of injection molding machine

Abstract

A disturbance estimating observer is provided, which estimates a load applied to a servomotor for driving an ejector axis. When an ejector operates, the disturbance load torque estimated by the observer is sampled for each specific period ( to j), and the data DA ( ) to DA (i, j) of (i+ ) ejector processes are stored in a table TA in the form of cyclic storage. From this table TA, average values DB ( ) to DB (j) of estimated disturbance load torques are determined in turn and they are stored in a table TB. From these average values, upper limit values DC ( ) to DC (j) and lower limit values DD ( ) to DD (j) of a permissible range are stored in tables TC, TD. When the determined estimated disturbance load torque has exceeded the permissible range, an abnormal load signal is outputted.