| From the literature survey, some theoretic researches and simulations have been done on Hydraulic AGC system and electro-hydraulic servo valve of rolling-mill system, and some important conclusions are achieved.FMV is one of the key components of hydraulic AGC system. The flow force simulation models of FMV and general plunger valve are set up, and some compare simulations of them are finished. To optimize the parameters of the FMV, a series of investigations of flow force compensation——circumfluence shaft compensation,are accomplished in the computer. FMV's steady flow force is declined largely by adopting flow force compensation measure, which make FMV's performance more well. The mathematic models of every component of the FMV-cylinder system are established, and the simulation model of FMV-cylinder system is also presented. A series of simulation of the dynamic characteristics are finished, different nature frequency and damping has different effects on the dynamic performance of the hydraulic AGC system, and their ramp position errors are different. Excellent nature frequency and damping are obtained in the end. They provide references for improvement of capability of hydraulic AGC system.The PID control strategy is one of the control strategies widely used in electro-hydraulic system, and it's parameters are easily adjusted. A new PID controller is designed and used in the AGC-system. Some dynamic simulation of the AGC system used the PID controller are completed in Matlab6.5. And simulation results show that the PID controller has very good results.To master the static characteristics of the FMV, a CAT (Computer-Aided Test) system is developed in the computer. A static test rig of FMV is set up, and some static characteristic tests(discharge characteristic test,flow-pressure characteristic test) and closed loop control test are accomplished in the laboratory. To study the test results, some useful conclusions are obtained. |
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