Research On Position Synchronization Control Strategy Of Hydraulic Redundant Drive Platform

Hydraulic redundant drive is widely used in industrial production because of its strong bearing capacity,large rigidity and simple driving structure.However,the structure of redundant drive and high rigid physical connection will result in strong mechanical coupling between drives,and the excessive coupling internal force caused by unsynchronism will reduce the operation stability of the system and the service life of components;moreover,the hydraulic servo system is a complex nonlinear and time-varying system,which increases the difficulty of control,and the synchronous control of hydraulic redundant drive has always been an important research topic in the industrial field.In this paper,for the hydraulic redundant driving platform guided by the ball rolling linear guide,the position synchronous control of the hydraulic redundant driving platform is studied from the kinematic analysis,the establishment of the coupling dynamic model,the design of the position synchronous controller and the synchronous control experiment.Firstly,the structure of the redundant driving platform is analyzed,and the relative rigid and flexible characteristics of the platform components and their connections are explored,and the relatively flexible guide rail pair is flexibly modeled.The linear motion of the beam and the neglected rotational motion of the beam are described.A two-degree-of-freedom dynamic model with rigid flexible coupling characteristics is established.At the same time,the nonlinear mathematical model of hydraulic servo system is established.Then,the single axis position tracking control based on sliding mode is studied for the nonlinear,time-varying and uncertain load effects of the hydraulic servo system.In order to reduce the chattering caused by sliding mode control,a sliding mode controller based on variable speed approach law is designed.At the same time,in order to improve the accuracy of synchronous control,the sliding mode cross coupling controller is designed by combining sliding mode control with cross coupling technology.Simulation and experiment verify the effectiveness of the controller.Finally,considering the effect of mechanical coupling internal force on the system,combined with the two-degree-of-freedom coupling dynamic model,a synchronous control method that combines internal force adjustment and motion tracking is proposed.The active internal force control strategy based on real-time distribution of driving force is adopted to control the rotating dynamic of the beam to restrain the internal force of the coupling constraint.By comparing with the simulation of position synchronous control of sliding mode cross-coupling,the proposed method can effectively suppress the coupling internal force while maintaining high-precision synchronous control,which verifies its better performance.The research content of this paper has certain reference significance for the improvement and practical application of the synchronous control strategy of hydraulic double-cylinder redundant drive.