Modeling Simulation And Modal Decoupling Control Strategy For Redundantly Actuated Electro-hydraulic Shaking Table

Vibration environment simulation is a basic experimental means of modern engineering technology, which use specific vibration simulation device and vibration control technology to simulate the vibration environment in product use or transport for product reliability detection, so as to provide important experimental evidence for product testing and technical improvement. Two degrees of freedom (2-DOF) Redundantly Actuated Electro-hydraulic Shaking Table provide larger driving force, and also improve the acceleration uniformity of the system.In this paper, the method of co-simulation of redundant shaking table for modeling and simulation is adopted. AMESim is used to build the hydraulic system, the mechanism part of the platform is built in Simulink/SimMechanics. Built in Matlab/Simulink, the whole servo control system consists of Three-state-controller, DOF control and redundant force control strategy, etc. Compared with the typical way of mathematical modeling, this way is much more simple and accurate. Then through the interfaces provided by the software, a general simulation model including mechanical, hydraulic and control system is constructed.Considering the elastic of load and foundation, the dynamic model of the shaking table is modified. The transfer function between mechanism displacement input and acceleration output is derived. The elastic parameters are obtained by parameter identification, and the curve of wave crest and trough phenomenon in the frequency characteristic is analyzed.The structure and dynamic characteristics of the hydraulic vibration exciter are very difficult to maintain consistency, which leads to the non-synchronization between the vibration exciter and the internal force coupling. The hydraulic cylinder is regarded as a hydraulic spring system and the free vibration modal equation of the redundant vibration table is analyzed. By means of the modal matrix and its inverse matrix, the redundant shaking table is transferred to the modal space. The simulation analysis shows that the decoupling control can effectively reduce the coupling between the 2-DOF of the redundant shaking table.Finally, the correctness of the proposed model is verified through comparing the simulation results with the experimental results. On the basis of this, compared with the mechanical and electrical integration model and test results, the modal decoupling control strategy can effectively reduce the coupling between the 2-DOF of the redundant shaking table, and improve the performance of the system.