Simulation Optimization Fuzzy Pid Temperature Control Program And Its Implementation

The task is to select a control method and use it in a TMS320F240 system. This system is used to control the temperature of the heater of a plastic processing unit. The technology demand of control method is: the rising time must be short, the temperature over the setting point must be small and the temperature must be able to keep steady.The task is divided into two:One is selecting a control method, and the other is programming it.For the plastic heater, there are many control methods to be selected.The first is the PID method. It's simple and easily realized. In most cases, it can satisfy the control demand. At present, in all of the control method in use, PID method presents over 80 percent. Its efficiency depends on its factors. It has the advantage to eliminate the error. But because of the conflict between quickness and the small temperature over setting point, it probably cannot satisfy the control demand.The second method can be fuzzy method, because it has the advantage of quickness. According to some papers, it can get quickness with a very small temperature over setting point. But because its theory is not very perfect, the control quality cannot be expected in advance. Furthermore, it's a reference method bases on the membership function of the input and output variables, to get the program is very difficult. And it has error when it comes steady.This paper analyses the advantages and disadvantages of the two methods and comes to the method of combining them together. It means that at the rising time the fuzzy method is applied, and at the steady time the PID is applied. This method can get the advantages of them and avoid the disadvantages of them.This paper does simulations of three methods and then selects the fuzzy-PID method.To get the code of this method and then use it in the TMS320F240 system, this paper selects a software fuzzyTECH to help the programming process. The software helps to enhance the development speed and ensure the program quality. Because the fuzzy control method has a lot of parameters, and any change of these parameters will change the code greatly, the usefulness of the software becomes great. So except for the simulations, another main task of this paper is to use the software to generate the code of the selected fuzzy control and then combine it with the whole control code.The following task is the experiments.The conclusion is that: the fuzzy-PID control method works. It also means that the development process using the software MATLAB and fuzzyTECH is workable.