Research On Structure Optimization And Model Control Of Resonant Heavy-load Hydraulic Shaking Table

Large artillery subject to strong vibrations during the transportation, can easily causevarious issues, such as sighting device loss, fasteners loosen, etc. Therefore, in order toimprove the product reliability, vibration test on artillery is required. During the process of test,potential failures of the equipment can be identified, and the design can be revised accordingly.Vibration test can not conduct without vibration equipment—shaking table. At present, foreigncompany’s products and technology of heavy-load shaking table used in the military field arerelatively mature, but their products are limited to be exported to our country. However,domestic existing shaking tables and technology can not meet the performance requirementsfor military equipment. Therefore, in order to meet a military enterprise’s demand for researchand development of a heavy-load shaking table, this paper studied the hydraulic heavy-loadshaking table. The main research contents and achievements are shown as follows:（1）According to the technical indexes—displacement amplitude:±80mm, accelerationamplitude:±5g, frequency range:1~200Hz, weight of the specimen:18t, an overall designwhich is driven by hydraulic shaking table is put forward; Simultaneously, to solve theexisting technical problems of heavy-load hydraulic shaking table: a) the cost in manufactureand usage increases sharply because of the excessive consumption in power when shakingtable works with high acceleration and large displacement in low frequency; b) the existinghydraulic servo valve can’t meet the needs of large flow and high frequency at the same time,this paper proposes a solution which can achieve the purpose of reducing the input power andsolving the problem of insufficient flow of high-frequency servo valve by resonant effectusing the variable stiffness characteristics of the gas inside the cylinder.(2) A scheme to realize variable stiffness characteristic is designed. In order to conductthe experimental research, the scaled variable stiffness system is set up. First, this paperdeduces the analytic expression of variable stiffness system, and proves from the perspectiveof theory that the variable stiffness resonance system scheme is feasible; Second, in order toverify the rationality and feasibility of the design theory, the scaled variable stiffness system isdesigned and set up; Finally,1~90Hz frequency sweep vibration test is conducted, in whichwe change the pressure of the gas in cylinder and the weight of system load respectively.Analyzing the test data, this paper comes to a conclusion that when resonant phenomenonoccurs, the vibration source’s vibration amplitude is improved by1times or so, and natural frequency of the system can be adjusted by changing the pressure of the gas in cylinder andthe weight of system load. Meantime, the adjustment rules are consistent with theoreticalanalysis.(3) The control simulation analysis of the valve controlled hydraulic cylinder system isconducted. First, the working mechanisms of the double nozzle flapper servo valve and thehydraulic cylinder are analyzed, based on the working mechanism, mathematical model ofvalve-controlled hydraulic cylinder system and the Simulink simulation model are established;Second, in the case of ignoring the internal and external leakage of the servo valve and thehydraulic cylinder and oil compressibility, the inverse model of the system is established; Atlast, the control simulation for the system model are conducted using PID and inverse controlalgorithm method respectively. Comparing the simulation results of two kinds of controlmethod, this paper comes to a conclusion that inverse control algorithm has betterperformance in controlling.(4) The vibration transfer and supporting table—shaking table is designed. In order toconduct the experimental research, a scaled physical model is also designed and manufactured.First, the overall structure of the table considering the special structure of the tested product isdesigned; Second, optimization design on the internal structure and size of the table isconducted using the Pro/E and ANSYS software; Third, the table’s dynamic characteristics arestudied by carrying out modal analysis; Fourth, to verify the correctness of the design andanalysis, a scaled physical model is designed and manufactured, according to the equivalentstiffness theory; At last, the static and dynamic experimental researches on the table areconducted. The experimental results are consistent with the results of finite element analysis.Thus, the conclusion can be drawn that the optimal design and analysis results of the table canbe applied to the research and development of actual table in the future.