Based On Generalized Predictive Control Plastic Molding Machine Temperature Control System

With the development of large-scale and very large-scale integrated circuit technology, especially with the invention and application of microprocessor, the control technology of packing machine is developing very fast. Now control technology is becoming an important motivity that promotes packing machine functions improving. The development of packing machine is later, and the automation foundation is inferior in our country. The technology in the control field of packing machine drops behind that in the advanced country in the world. It causes that the development of our country's packing machine always stays on the middle and low level. The lag of control technology has become a bottleneck of improving the packing machine of our country. So, it is a urgent task to develop the control system of top grade packing machine and to improve the automatic level of packing machine.This paper analyses the aim of temperature control system of plastic-absorbing and designs the hardware circuit using one-chip computer as it's core and using temperature transducer, magnifying circuit, A/D converter, watch dog as it's parts. Paper designs software of control system basing on the hardware circuit.Considering the character of plastic-absorbing, the controller uses generalized predictive control algorithm. Generalized predictive control is a computer control algorithm basing on model. It develops on 70's of 20^th century and it's a new control algorithm. Because of it's adaptability to complex industry condition it solves a lot of difficulty of industry producing and show gigantic charm.First the basal generalize predictive control algorithm is presented. Effect of the basal algorithm is very good, but it must computes a lot on time. Considering the character of controlled object and the controller basing on one-chip computer, this paper show three improved generalized predictive control algorithm.(1) a generalized predictive control algorithm having PID frame; It deduces the parameters of controller using generalized predictive controlalgorithm and it characterizes of easy parameters adjusting and strong robust; (2) a direct generalized predictive control algorithm; this algorithm deduces the control output directly. It makes one-chip computer few computing; (3) a improved direct generalized predictive control algorithm; This algorithm use the true step responding or proximate step responding and not desiring the exact step responding. The simulating results show that these algorithms can be used in the temperature control system of plastic-absorbing machine.