Soft Variable Structure Control for Sealing Temperature of Bag Making Machine

In order to solve the problem with fluctuation of heat-sealing temperature caused by periodical motion of sealing block for bag making machine, this paper has proposed an intelligent control solution that combines static feed-forward with soft variable structure and soft saturation. The dynamic performance of sealing block temperature control system characterized by a long time delay has been improved in this scheme by reducing operation area of the feedback regulator and applying multi-saturation technique to the integrator, and the supply voltage variation of electric heating system is compensated with adaptive feed-forward control to improve the anti-jamming ability of temperature control system. Results of both Matlab simulation and application in high-speed bag making machine have shown that this scheme features a fast and steady dynamic control and a high-precision temperature control over sealing block. The paper has also presented a technical solution to achieve the six-channel intelligent controller over temperature of sealing block based on MSP430F149 composite signaling processor as control core and bidirectional thyristor as power driver.