Design And Research Of Electro-hydraulic System By Coupled Parallel Driven For Vertical Vibration And Force Loading

Large-scale electro-hydraulic system by coupled parallel driven is mainly applied to vibration and force loading environment simulation,andassess the ability of the tested object to maintain the original performance under vibration or load excitation,which is of great significance to improve the comprehensive performance of the core components in large engineering.Hence,supported by the National Natural Science Foundation of China Project “Research on coordination control of super-redundant electro-hydraulic system subject to vibration and force loading”(item number: 51575511)and the Jiangsu Provincial Natural Science Foundation “Research on hybrid control strategy for large-scale structure fatigue test rig”(item number: BK2012132),this thesis researchs on the relative control strategy of electro-hydraulic system by coupled parallel driven for vertical vibration and force loading.First of all,this thesis based on the experience and the construction method of the domestic and foreign relevant test rig,and combined with the working conditions and the relevant performance parameters,the mechanical,hydraulic and control unit of electro-hydraulic system by coupled parallel driven for vertical vibration and force loading are designed in detail.The finite element analysis is carried out by using ANSYS software for the main force components such as Longmen frame,reaction wall,bearing platform and ball hinge.And then build a coupled parallel drive electro-hydraulic system test bed.Secondly,considering the nonlinear characteristics of electro-hydraulic system,the nonlinear model of hydraulic actuator is established.The basic independent control between the multi-hydraulic actuators of the experimental platform is realized by using the independent control strategy of freedom degree.On this basis,pressure stabilization and internal force feedback controller for internal force decoupling control were further introduced to eliminate the problem of internal force coupling caused by the mechanical installation error,electrical device zero drift and servo valve opening zero and other causes.The effectiveness of the decoupling strategy is verified by experiments.Then,in order to improve waveform reproduction accuracy of the electro-hydraulic vibration system by coupled parallel driven,based on the TVC control strategy to achieve the initial closed-loop acceleration control,combined with the system identification algorithm to identify the DOF acceleration parameterization model,and further use the zero-amplitude tracking technology to design the DOF stability inverse model,then the control strategy of feedforward inverse model of the vibration system is established.And the effectiveness of the control strategy is verified on the experimental platform.Finally,in order to eliminate the adverse effect of the vibration action on the precision of the vertical force loading control for electro-hydraulic system by coupled parallel driven,the feedforward velocity compensation strategy is used to suppress the vibration disturbances during the vertical force loading process.On this basis,the method of constructing the disturbance observer based on the inverse model is studied to form the force loading compound control strategy combined with the disturbance observer and the feedforward speed compensation control.The effectiveness of the proposed control strategy is verified by experiments.