Servo Control Study Of Long Stroke Vibration Testing System

With the rapid development of science and technology,the engineering structure gradually tends to be large and integrated,and the vibration environment is the main environmental factor that affects the stability of large structures.Therefore,it is necessary to conduct simulated vibration tests on the structures.The six-degree-of-freedom redundant drive hydraulic vibrating table is designed and researched on this basis.When the movement displacement of the vibrating table is required to be large,due to the characteristics of the redundant driving parallel mechanism,it will cause the vibrating table to produce a large number of involved motions and couplings.Internal force.Therefore,this topic upon the background of the project “the facility for advanced structural test(FAST)” developed jointly by China State Construction Engineering Corporation(CSCEC)and Harbin Institute of Technology(HIT),the servo control research on long-stroke vibration test system.When the redundant driving hydraulic vibrating table adopts a dof control method based on the linearization near the zero position,the long-stroke motion will cause a large displacement error of the hydraulic cylinder,which in turn causes a large position following error.In order to improve the position following accuracy of the system,a dof control algorithm based on the kinematics is finally adopted,but the current kinematics positive solution has the characteristics of low resolution accuracy and poor convergence.Therefore,this paper proposes a positive solution algorithm based on closed-loop feedback real-time solution,The simulation analysis was conducted to analyze the stability and convergence of the algorithm.Another feature of the redundantly driven hydraulic vibration table is the internal force of the system,this subject first derives the dynamic model of the system,and according to the dynamic model,the mechanism of the internal force of the system is analyzed,and the specific form of the internal force of the system is obtained.Then,the power mechanism model of the hydraulic cyli nder is deduced to provide the power driving model for the subsequent simulation.When the system adopts a dof control method based on the linearization near the zero position,the system will inevitably generate a large internal force,and even damage th e mechanism in severe cases,therefore,the control algorithm is improved.The simulation results show that the improved method can red uce the system's internal force,but its controller design is difficult,so it's difficult to achieve.Finally,the internal force of the system under the kinematics-based degree of freedom control method is studied,and an improved internal force control method is proposed.The redundant driving hydraulic vibration system will be affected by disturbing factors such as inconsistent driving characteristics of the hydraulic cylinder,zero drift of the servo valve and sensor measurement error in the actual project.Finally,simulation analysis will be conducted under the influence of the disturbing factors.