Automatic Control System Based On Fuzzy-Pid Strategy For Sewage Treatment

The paper i s based on the reconstruct i on of automot i ve supervision and control systems in Shenzhen Binhe sewage treatment plant, which belongs to the project of Chengdu Zhonggong Science and Technology Company. According to the practical requirements and compared with several common kinds of automotive supervision and control systems, a distributed IPC+PLC control system which is connected by Ethernet and CCLINK field bus is proposed.Firstly, there are many difficulties in the control of blast and aeration system, such as intermittence, non-linearity, delay etc. So the fuzzy-PID strategy is applied to control it, while the DO is as control object to be used to construct the math model. And the simulation results of fuzzy-PID strategy are compared with the one of PID strategy and fuzzy strategy.Secondly, the fixed parameters of fuzzy-PID cannot get the satisfied results in different cases, so in this paper the Genetic Algorithm is used to optimize several key parameters: membership function, fuzzy rules, quantization factors and scale factor. Then the control results are simulated with MATLAB, and compared with the results of PID and fuzzy control optimized by GA. At last, aiming to save energy, promote water quality and protect high-power devices, this paper chooses QPLC and FXPLC made in Mitsubishi to build the automotive supervision and control system of pump station and aeration system, and detailedly describes the hardware of the whole sewage treatment plant and the software PLC flow chart. The supervision and control system of pump station is carried on now, and satisfied results have been achieved.