Study On Electro-hydraulic Servo System And Control Method Of Large Diameter Thin Wall Tube Spinning

Spinning technology,as an advanced manufacturing technology,has been widely used in aerospace,artillery,weapons and other military products,automobile,aircraft and other civil industries after years of development,and has become the key technology for processing thin-walled rotating cylinder parts.As the key equipment of spinning forming technology,spinning machine embodies the level of spinning technology,and plays a decisive role in the quality and processing accuracy of the spinning products.Therefore,the research of spinning machine is of great significance to the development of spinning technology and the improvement of spinning product quality.For the problems of cracking,bulging,and cracking of steel pipes due to load pressure changes during the spinning of large-diameter thin-walled tubes,a new hydraulic system applied to the spinning machine of large-diameter thin-walled tube is proposed in this paper,and its control system and control strategy are studied,which laid a foundation for the independent research of automatic and intelligent spinning machine of large-diameter thin-walled tube in China.Firstly,this paper analyzes and classifies the factors that affect the thickness of steel pipe spinning in spinning process,and proposes a method for controlling the spinning thickness of the steel pipe.At the same time,it refers to the control theory of rolling mill AGC and proposes the compensation control of hydraulic cylinder reduction in spinning process,and calculates the compensation amount of steel tube spinning thickness.Further analyze the structure of the hydraulic control system of the spinning machine,design the hydraulic system of the spinning machine,calculate and determine the main parameters of the hydraulic system,and establish the three basic equations of the hydraulic system,derive the system transfer function,build the mathematical model of the pressure-position conversion module and other components,and finally sets up the control block diagram of the hydraulic system of the large diameter thin-walled tube spinning machine.In order to verify the feasibility and stability of the hydraulic control system,this paper uses the AMESim software to simulate and analyze it based on the designed hydraulic system schematic diagram,and constructs a pure position closed-loop control and position-pressure composite control system model for comparative analysis,studies the dynamic characteristics and anti-interference ability of the hydraulic system under different control strategies.The simulation results show that when the hydraulic system is controlled by a combined position-pressure control strategy,the response time of the system is shortened,the accuracy is improved,and the ability of resisting load interference is also enhanced.Considering the influence of non-linear characteristics and uncertain factors in the system during operation,in order to further improve the control accuracy of the hydraulic system of the spinning machine,a cascade controller combined with disturbance observation is designed in this paper to control the spinning wheel of the large-diameter thin-walled tube spinning machine.Disturbance observation is used to estimate and compensate the uncertain parameters in the system,then the cascade controller is designed using the synovial membrane control theory,and finally SIMULINK and AMESim are used for joint simulation.The research results show that,regardless of whether the system has load disturbance or not,the position accuracy of the cascade controller based on disturbance observation to control the hydraulic cylinder is higher than that of the PID controller to control the hydraulic cylinder,and the displacement tracking error is significantly reduced,and the system resists load disturbance Improve ability.