The Design And Implement Of Smart Valve Positioner On Base Of Fuzzy Control

As the development of technologies control systems in industry manufacture process become more complexity and uncertainty. Correlation and randomicity will change incidentally when the environment and time change .So traditional control technique based on mathematical model is harder to control.Fuzzy control is a kind of human imitating technique which is independent on the controlled plant' s mathematical model.It utilizes the knowledge and experience of experts to carry out rationalization.As a results,it has good robustness.But it is lack of the ability of self-learning or self-adjusting after the fuzzy control rules have been set off-line.Neural network has the ability of self-learning in spite of its nonlinearity mapping similar with Black-Box.The abilities of self-learning and expression of the whole system will be improved when they connect together.Valve positioner is a typical nonlinearity system.But fuzzy control and neural network control can implant intelligent control.So a controller of fuzzy neural network and its learning algorithm are proposed in this paper ,and then the regulation of self-learning of the fuzzy neural network are researched.The main points of this paper are as follow:1,By analyzing the controlling technology of the concerned intelligent by Valve Positioner at the present time,Tolal plan design aims at the controlling circuit of low power,single chip microprocessor. In addition,the relevent solving method are also gived out.2,the method of CRI reasoning and checking in table in the theory of the fuzzy control is applied in this control system. With this way , building mathematic model for the controlled process is not only spared , but also has a high real-time respondent speed, and the control accuracy is further improved.3,making use the function of the memory and the study based on fuzzy neural network ,adopting genetic algorithm and Back-Propagation algorithm together,impling a type of improvement controlling system.4,The paper described the HART protocol and the interface card for intelligent positioner based on HART protocol ,and gived out the solving plan.The field of running shows that the steady precision and the dynamic response characteristic of the system are all reach demands predicated.The system features reliablity, easy operation and maintenance.