| Powder press is the basic equipment to complete the molding of powder metallurgy parts.Its products have a high cost performance.Therefore,they are widely used in power electronics,machinery manufacturing,automotive,aerospace and defense military and other fields.During the pressing process,the load force is nonlinear and time-varying due to the powder characteristics,and the structure of the electro-hydraulic servo system is complex,and there is nonlinearity and time-varying parameters,which makes it difficult to improve the control accuracy.Therefore,it is of great practical significance to study the control strategy of the powder press system for the disturbance problem.The design of the powder press system and the pressure control strategy are carried out in the light of the disturbance,nonlinearity and parameter time varying of the variable load force in the control system of the powder press.First,the principle design of the hydraulic system,the design of the electric control hardware system and the design of the control software system are carried out for the powder press.Then the mathematical model of the pressure control system is set up.Based on the mathematical model of the pressure control system,the linear auto disturbance rejection controller is designed.The stability analysis and parameter tuning of the designed controller are carried out.The simulation analysis of the given disturbance,the estimation error and the contrast step response of the PID is carried out,and the linearity is verified.ADRC has good tracking performance and anti disturbance performance.Finally,the 260 T powder press was used as a platform for experimental research,and real-time suppression step response experiments and slope tracking experiments were performed.The results show that the designed linear auto disturbance rejection controller improves the anti-disturbance capability of the pressure control system of the press and improves the precision of the compacted products. |
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