Control method of BOPP (Biaxially-oriented Polypropylene) biaxial stretching system

Abstract

The invention provides a control method of a BOPP (Biaxially-oriented Polypropylene) biaxial stretching system. With regard to an arbitrary three-motor subsystem in a stretching section of the system,the system comprises a prepositioned shaft, a first tension roller, a main driving shaft, a second tension roller and a post-positioned shaft; two distributed controllers are used for controlling, wherein the first controller is used for controlling a prepositioned shaft motor and a main driving shaft motor and the second controller is used for controlling the main driving shaft motor and a post-positioned shaft motor; meanwhile, the first controller and the second controller are used to share one part of output through superposition of control factors a and b, so as to control the main driving shaft motor. According to the method provided by the invention, the two continuous controllers are used share one part of input and output through superposition of the control factors, so that thedecoupling capability of speeds and tension of the system can be remarkably improved; the subsystem is expanded into a multi-motor winding system in a biaxial stretching process; meanwhile, a thin film longitudinal and transverse thickness control model is also designed, so that synchronous and accurate control on the speeds, the tension and the speed of a stretching process is realized.

Description

technical field [0001] The invention relates to the technical field of control, in particular to a control method for a BOPP biaxial stretching system. Background technique [0002] BOPP is the abbreviation of "Biaxially Oriented Polypropylene", and BOPP film is a biaxially oriented polypropylene film. The production of BOPP film is to first make the melt of high molecular weight polypropylene through a narrow and long die into a sheet or a thick film, and then in a special stretching machine, at a certain temperature and a set speed, simultaneously or step by step A film made by stretching in two vertical directions (longitudinal and transverse) and undergoing appropriate cooling or heat treatment or special processing (such as corona, coating, etc.). [0003] In the BOPP film winding transmission and stretching system, the main control objective is to independently control the speed and tension of each drive roller under the disturbance of the roll diameter and the change...

AI Technical Summary

Problems solved by technology

However, these disturbance factors and control quantities often interact and cannot be described individually

The production process of casting sheet-longitudinal drawing-horizontal drawing-drawing-winding of the whole system includes a series of actuators (drive motors), and it is difficult to realize the control of multiple motors by using a global multi-variable controller

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