The invention relates to the technical field of injection molding
pressure control, in particular to a multi-stage pressure closed-loop compensation
system and method for high-precision double-color injection molding, and the
system comprises an interface gradient positioning module, a flow resistance
state recognition module, a fitting function reconstruction module, a
time sequence deviation triggering module and a
gain reverse correction module. According to the method, the high-density measuring
point data is collected, the interface
radial pressure gradient change is extracted through the
finite difference method, the stably-arranged nodes at the material intersection can be accurately locked, and the flow resistance state of the flow channel is judged according to the slope difference value of the
screw speed and the pressure
intensity change. A linear boosting or index slow increasing strategy is automatically switched to reconstruct a
pressure function form, local high-pressure accumulation characteristics of a product sensitive area are accurately matched, the
coincidence degree of a time window drift trend and a slope sudden change window is monitored, historical displacement and pressure errors are converted into
backstepping factors through an iterative learning model, and the
backstepping factors are calculated. And a driving
gain curve is initialized and revised, so that forming deviation caused by thermal drift of equipment is eliminated.