| The thesis comes from the Double-side turntable die spotting press project cooperated by NPU908 with Shannxi forging and rolling equipment works. The main work is studying high-accuracy position control system of double-side turntable die spotting press. The system uses proportional orientation valve with high echo performance. The control precision of the slider with 2400mm effective stroke can reach 0.05mm. The properties of the position control system are not exigent, only the dynamic non-overshooting and the stable-state-precision are considered. The system has given out satisfactory result when used in practical engineering, 0.03mm position control precision has been achieved, On account of dead band, the performance of proportional valve is worse than that of servo valve, but some advantages of proportional valve has made it more fit for industrial control.The main work of the thesis is as follows:1.The feasibility of the scheme in engineering is discussed by means of analyzing the strategy of position control system.2.The mathematical model of the position control system is established and analyzed in theory. Mainly the lJroperties of proportional valve are discussed,3.Employing the mathematical model, computer simulation is carried out. The influence on system precision and the methods of decreasing the bad effect of the dead band are studied. In the course of simulation, PD control, improved PID control, self-learning control and adaptive control are taken to enhance the system precision. Via studying the control law, the way to improve the system control precision is found.4.The realization of PLC control in engineering is introduced briefly. |
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