Study On Modeling And Sliding Mode Control For Vibration System Of Continuous Casting Mold Driven By Servo Motor

Continuous casting mold is an important equipment in the iron and steel production process,its performance has a significant influence on the quality of slab,and nonsinusoidal vibration way of contiuous casting mold is considered to be one of the key technology of high efficiency continuous casting.Based on the vibration displacement system of continuous casting mold driven by servo motor in laboratory,this paper carried on the mechanism analysis of system structure,established mathematic model of continuous cast mold vibration system,designed the sliding mode controller,and constructed perturbation observer.The main work of this paper is as follows:Fistly,the paper summarized the structure of continuous casting molds driven by servo motor vibration displacement system and analyzed the operating principle of continuous casting mold vibration system.In order to lay the foundation for displacement tracking control,the design of sliding mode variable structure controller was introduced briefly.Secondly,based on the vibration system of continuous casting mold driven by servo motor system in laboratory,the servo motor system and the mechanical transmission part were analyzed mechanically,and the viscous friction coefficient,moment of inertia and other parameters were estimated so as to construct a mechanism model of the whole system.Under the same signal input,the validity of model was verified by comparison between actual system output curve with model output curve.Then,considering that the vibration displacement tracking accuracy is low due to the existence of disturbance,such as reduction ratio measurement error and load torque in the vibration displacement system of continuous casting mold driven by servo motor,a kind of global fast terminal sliding mode controller is designed,and radial basis function neural network observer is constructed to estimate the total uncertainty,and then the estimation value is compensated to the controller.In this way,the tracking controller accuracy is improved.Finally,in order to weaken chatting phenomenon in the process of approaching sliding mode surface and improve convergence speed,a backstepping sliding mode controller based on double power approximation law is designed,at the same time,the load disturbance is estimated on real time by observer.Then,the simulation results verified that the designed control method can reduce system chatting and increase convergence precision.