The Analysis Of Hydrualic Systems Of Φ25Fixed-scale Steel Bar Cutter

This paper studies the hydraulic systems of Φ25fixed-scale steel bar cutter, includingthe shearing hydraulic system and hydraulic servo system. In order to guarantee theaccuracy of specified length of the steel, the hydraulic servo cylinder keeps pushing theshearing hydraulic cylinder fixed on a car in the working process of the steel bar cutter.And the pushing speed should be the same as the heading speed of steel in the process ofshearing.First of all, we analyse the shearing hydraulic system, which is an open loophydraulic system. The reversing valve in the shering hydraulic system adopts two kinds ofschemes, scheme one is two-position and four-way electro-hydraulic directional valve,there is a cartridge oil return restrictor at the port P of the pilot valve,which decreases thehydraulic impact caused by reversing. Scheme two uses two-way cartridge valve which ismore widely used in high-flow hydraulic systems, there is a pilot valve controlling fourtwo-way cartridge valves. With the aid of HCD library of the AMESim, the results of thesystem modeling and simulation shows the sheaing time of scheme one is shorter and theimpacts of the pressure and the rate of flow is smaller.Terefore,scheme one is available.Then I study the hydraulic servo system which includes sevo valve controlledunsymmetrical cylinder and is a position closed-loop control servo system. The softwaressuch as AMESim and MATLAB/simulink are applied to the modeling and simulationhydraulic servo system. Due to the uncertainty of the hydraulic servo system itself and theoutside interference, conventional PID controller exists the disadvantages such as lowcontrol precision, poor stability and poor anti-interference ability. In order to improve thesituation, this paper applies the fuzzy adaptive PID controller, fuzzy adaptive P controllerand model reference adaptive controller designed by the adaptive law using fuzzy setmethod, model reference adaptive fuzzy control MRFAC to the hydraulic servoposition-controlled system. Except for analyzing two kinds of structure of the MRFAC,the reference models are respectively adopted by two forms of servo valve controlsymmetrical cylinder and the reduced order model. The responding speed of fuzzy adaptive P controller is fastest, but the fuzzy adaptiveP controller can not eliminate the steady-state error existed in the system.Both the fuzzyadaptive PID controller and MRFAC meet the demands of the system, which improve theanti-jamming ability, the rapidity and stability. The MRFAC controller is superior to thefuzzy adaptive PID controller, which mke the minimum overshoot and the fastest rate totend to be stable.