The main research contents of this dissertation focus on two key problems on the designing of advanced plastic injection molding machine controller. The first key problem is about the accurate and robust temperature controlling of multi-zones cylinder. For injecting qualified product, the cylinder must have high temperature control accuracy. However, the coupling influence between the adjacent zones of the cylinder is very strong and the parameters of the cylinder are time-varying. So the classic PID algorithm can not work efficiently. Usually, the fuzzy adaptive algorithm is employed to solve this problem. This paper has proposed a control method named the adaptive temperature control algorithm based on expert rules too. Both the two algorithms belong to stabilizing controlling. They have a good performance in most situations except for the synchronous heating function and the cylinder heated by the ceramic heater which has a great time-constant. So, the self-turning PID algorithm is proposed in this paper for solving this problem. Due to the self-turning PID controller must include some kind of parameter estimation algorithm, the recursive instrumental variable method (RIV) is employed to avoid computing noise model of objects and ensure the consistent progressive convergence of model parameters in the environment with non-white noise. In addition, we introduce the forgetting factor to modify the RIV method to keep the online continuous identifiable capability for time-varying parameters. It has been shown that this controller has better stability, high accuracy and good adaptability to the variety of environmental conditions and cylinder specification in the factory. The second key problem is about variable frequency technology for energy saving of plastic injection molding machine. This technology is the trend of plastic processing machinery in the future. The paper researches the energy saving mechanism and implementation method of the plastic injection molding machine. The critical technology is the Field Oriented Control of the 3-phases AC induction motor. The paper makes a reasonable scheme and carrys out the first step test. Finally, this dissertation introduces two types of controller as S60 and S80 which is developed by the author. It illustrated the structures of the hardware and software, the appearing problems and the solutions.
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