Hydraulic Leveling Control System

Roller flattening machine is a pivotal equipment in the material flattening industry. But high-precision hydraulic position servo control roller flattening machine can't be made in china. Its most important problem is position control precision, which directly affects product quality. So this paper focuses on the position control system of hydraulic roller flattening machine.Correlation identification is used to identify the position control system. The result of system identification is the transfer function close to the real system. In SIMULINK, the transfer function replaces the real system. Control algorithms are simulated in the SIMULINK, whose results guide to do several field experiments. The most suitable control algorithm is found after the field experiments, and the control performance meets the need of flatting disk saw firstly.Chapter one is concerned with the background, significance and primary content of the research. At first, the background is introduced, including the technical actuality of material flattening industry and roller flattening machines in the world, and the trend of disk saw process. The most important significance is to do homemade work. Then the actuality and development of modern electro-hydraulic servo control algorithms are also summarized. At last, the particular content of the paper is decided.Chapter two discusses the principle and component of hydraulic roller flattening machine. Firstly, the principle about board flattening is introduced, and the whole mechanical construct is explained. Secondly, the control object is put forward, and the control system principle is analyzed integrally, made up of velocity subsystem and position subsystem. Lastly, the principle and characteristic of some important parts of hydraulic subsystem and control subsystem are introduced.Chapter three is concentrated on position control system identification. The first part introduces system identification, and draws the conclusion that the correlation identification algorithm is the best one. The second part discusses experiment design and experimental data calculation. The third part sets up the position system transfer function mathematical model, and resolves the parameters of the system transfer function. The last part validates and revises the model.Chapter four is the emphases of the paper, which studies the control algorithms of position control system. The first section analyzed the error resources and takes some measure. The second section does simulation study about several control algorithms, including traditional PID control, self-tuning fuzzy PID control, fuzzy rule self-tuning control, and position synchronization control construct. The last section does field experiments and decides the most suitable control algorithm and control parameters.Chapter five deals with the sum-up of the research work and points out the shortcomings. It also prospects the further work.The appendix explains the software of PLC controller of hydraulic roller flattening machine.