Can Bus-based Sewage Treatment, Research And Design Of The Adaptive Control System Of Diffused Aeration Process

This thesis was focused on the problem of sewage processing in adaptive control that was based on integrated oxidation ditch, and produced the model of Field Distributed Control System based on CAN bus. It adopted three field controllers and central controller to construct the control system, developed the distributed data acquisition and control system based on CAN bus. It also constituted the mathematical models of dissolutive oxygen and pH value, and projected an adaptive control algorithm for each model, finally made signal simulation for the algorithms.In the technical part the thesis was based on the discussions in the new technology and the running mode of sewage processing. It produced that the usage of integrated oxidation ditch was the developing trend of modern sewage processing technology, analyzed the evolvement and innovation of the technique in eliminating nitrogen and phosphor, developed and optimized the whole flow of technique.In the part of whole designing the thesis discussed the communication model, technology criterion, frame structure and error types of CAN bus, and analyzed the principle, character and types of the adaptive control. It also gave the whole designing, and analyzed the hardware composition, at length gave the structure designing of the system and the function designing of the central controller and each field controller.In the part of distributed data acquisition and control system a field control system with CAN bus was developed based on integrated oxidation ditch in a sewage processing plant that was introduced. The CAN bus interface hardware was proposed here, and the overall architecture, hardware composition, software functions and the functions of each controller were discussed in detail.This thesis also set the variables and methods of controlling, developed the algorithms of PID adaptive control based on Neural Network and Least squares with restriction. They advanced the effectivity of sewage processing and lowered the waste of energy. Through the signal simulation of algorithms the thesis provided the sufficient basis for the optimizing of the controlling models and correspondent algorithms.The three field controllers of the system had multi-master structure, high real-time capability and high reliability communication. The whole and local designing of the system had the high ratio of capability and cost, and adopted high effective and highreliable algorithms, so the FDCS owned high real-time, efficiency, reliability, open, economy and expedient operability.The designing of the system adopted the idea of industrializition, viewed the technology reconstruct of the sewage processing plant and the product of the achievement in scientific research. This thesis regarded the whole process of blast and aeration as control object, and constituted its mathematical model, which was original in the civil. It also originated a new domain for the applications of control theory in the sewage processing.