水田激光平地机调平系统动力学模型的验证试验
Verification experiment on dynamic modeling of leveling system of paddy field laser leveler
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摘要: 机械液压系统的动力学模型是表达系统动态特性的有效方法之一,常应用在运动机构的高精度控制设计中,然而在应用模型之前,其准确性需要经过试验验证。该文在课题组已建立了水田激光平地机调平系统的动力学模型,且对模型的准确性做了初步验证的基础上,对模型的准确性进行更严谨的试验验证与完善。首先,设计并搭建一个接近模型假设前提的试验平台,即为平地铲物理系统提供稳定安装平台,其次是各铰链连接间隙合理、配备比例流量换向阀。然后展开试验,这主要包括两部分:第一是比例流量阀的流量增益系数的标定,通过大量的恒流输入和正弦输入试验,同时测定电流与流量后,得出其试验关系。第二,对调平系统进行正弦振动试验,通过给控制电路不同频率与幅值的输入电流,对比平地铲水平倾角测量结果与相同输入时的仿真结果。试验结果表明,所选用的比例流量换向阀输入电流与输出流量存在较理想的比例关系;平地铲水平倾角测量值与仿真结果比较吻合,模型能够反映调平系统的动态特性。该文为下一步调平系统结构改进,以及实现基于动力学模型的调平控制算法提供理论基础,采用的比例阀流量增益系数标定方法和系统模型验证方案对其他机电液一体化装备的动力学模型验证具有借鉴意义。Abstract: Dynamic Modeling is one of the most effective ways to show dynamic characteristics of mechanic-hydraulic system.It is always used in high presion control of the moving part, especially in high speed. However, it must be verified before used in controller designing.This paper pays much attention to verification test on dynamic modeling of leveling system of paddy field laser leveler.The test conditions was more rigorous than before, which can ensure the accuracy of modeling . The verification test was based on that dynamic modeling was established by group before and modeling was tested simply, which showed the accuracy of modeling.In this paper a experimental platform was designed and built, which was close to the model assumptions.The platform should firstly provide a stable platform installation for the physical system of shovel.Secondly it should have proportional flow valve.Last but not list, The clearance between the hinge should be small.Then carried out the test, which mainly included two parts.First was the calibration of flow gain coefficient of proportional flow valve through constant current input and sinusoidal input test.Measured the electric current and flow rate data at same time,then propose them by Matlab.Second, sine vibration test for the physical system of shovel through inputing different frequency and amplitude of the input current by control circuit to the physical system of shovel.Then Comparing the ground level obliquity Angle measurement results with the simulation results which happened in same condition.The test results showed that the ground level obliquity, compared with the results of simulation model could response the leveling system dynamic characteristics.This paper can be useful in these terms.First, it lays foundation for perfecting the leveling system structure in future and realizing the leveling control algorithm based on dynamic model foundation.Second, the calibration method of the proportional valve flow gain coefficient can be reused to figure out the parameter of the proportional valve flow gain coefficient.Last but not list, the scheme of system model validation for dynamic modeling of other integrative technique of mechanics-electronics-hydraulics equipment validation also can be used and be referenced.