Research On The Control Algorithm Of Direct Drive Electro-hydraulic Servo Powder Press

Powder metallurgy products are widely used in the fields of electrical and electronics,aerospace and defense,and their dimensional weight accuracy depends directly on the control performance of the electro-hydraulic servo system.In the powder press forming process,the electro-hydraulic servo system control of the driving press faces the following problems:(1)The electro-hydraulic driving system of the powder press is a non-linear model with uncertainties and external disturbance uncertain system;(2)The load force of powder forming is a strongly nonlinear load force that changes exponentially.Therefore,it is of great practical significance and academic value to study an electro-hydraulic servo system with good powder forming process adaptability.Taking the powder press direct drive pump control servo system as the research object,the following researches have been done for the purpose of improving the position control accuracy of the system by taking disturbance rejection as the entry point for the above two problems:First,the mathematical model of the powder electro-hydraulic servo system was established.According to the problem of high nonlinearity,friction force and inaccurate modeling during the pressing process,the auto-disturbance rejection controller was designed and the controller parameter tuning method was given.The integrated disturbance of the system can be estimated by the extended state observer,and the compensation is based on the compensation.Therefore,the controller can not depend on the precise mathematical model of the controlled object.Second,the change of powder forming load force is the main disturbance to the powder electromechanical system.In order to compensate for this disturbance,based on the experimental study of the powder pressing force,a powder forming compression force model was established,which was used to generate electricity.The mathematical model of the electro-hydraulic servo system was combined and an inversion sliding mode controller based on model compensation is designed.Finally,for the integrated disturbance of the system,an extended state observer is designed to estimate and compensate it.The experimental results show that the designed controller can meet the requirements of control accuracy,and the precision of the experimental sample is kept within ±0.05 mm,which has higher control accuracy than the traditional controller.