电液伺服阀静动态特性测试过程中的关键问题研究

发布时间：2018-01-16 21:09

本文关键词：电液伺服阀静动态特性测试过程中的关键问题研究　出处：《兰州理工大学》2012年硕士论文　论文类型：学位论文

【摘要】：伴随工业技术快速发展，电液伺服控制系统应用愈加广泛，电液伺服阀作为其中的关键部件，其性能好坏对于整个控制系统尤为重要。电液伺服阀性能测试是研制和使用电液伺服阀过程中不可或缺的一个关键环节，在电液伺服阀技术飞速发展的同时，客观上要求与之相关的测试技术也要进一步的发展和完善。本文针对伺服阀测试过程中如何提高自动化程度、提高测量精度、减小人为因素影响等问题，以计算机辅助测试技术为基础，发挥虚拟仪器技术优势，紧紧围绕电液伺服阀自动测试系统研制过程中诸如动态流量的测量、误差的来源、数据的采集与处理、配套软件的设计、减小测量误差的方法等一些关键问题展开研究，主要研究内容包括以下几个方面：首先，对影响电液伺服阀的各项性能指标进行理论分析，制定电液伺服阀静动态特性的测试方案，重点研究电液伺服阀动态特性测试的原理和方法，通过测量动态油缸活塞杆运动速度来间接测量伺服阀的动态流量，采用扫频和谱分析两种不同的方法进行电液伺服阀的频率特性测试。其次，完成对测试过程中所需要的包括计算机、数据采集板卡、传感器等主要硬件的选型；设计测试系统的供油方案，通过比例溢流阀和比例减压阀配合保持油源的稳定，通过蓄能器吸收压力脉动，通过在泵出口和阀入口处设过滤器来保证油液清洁度，通过比例节流阀完成测试系统自动加载。再次，详细研究电液伺服阀动态特性测试中的各种影响因素：为使动态测速油缸满足小质量、低摩擦、少泄漏的要求，基于活塞溶腔最小原则计算动态测速油缸的尺寸，确定动态测速油缸的材料及密封方案，估算动态测速油缸的固有频率；建立电液伺服阀动态特性测试系统的数学模型，通过Similink仿真来研究动态测速油缸固有频率、运动组件质量、管道及油缸两腔容积以及位置定中闭环系统等因素对电液伺服阀动态特性测试过程和结果的影响，从而也验证动态测速油缸设计的合理性和测试方案的可行性。最后，研究通过虚拟仪器实现试验中所需要的激励信号发生和数据采集处理等功能的方法；基于图形化编程软件LabVIEW编译测试系统程序，通过软硬件相互配合实现电液伺服阀静动态特性测试的功能；从软件和硬件两个角度分析测试过程中误差的来源，，在软件方面采取数字滤波、平滑窗口等措施并在硬件方面采取屏蔽隔离、单点接地等措施来减小测量误差。
[Abstract]:With the rapid development of industrial technology, electro-hydraulic servo control system is more and more widely used, electro-hydraulic servo valve as one of the key components. Its performance is very important for the whole control system. The performance test of electro-hydraulic servo valve is an indispensable key link in the process of development and use of electro-hydraulic servo valve, while the technology of electro-hydraulic servo valve is developing rapidly. This paper aims at how to improve the degree of automation, improve the measurement accuracy and reduce the influence of human factors in the process of servo valve testing. Based on the computer aided testing technology, the advantages of virtual instrument technology are brought into play, and the measurement of dynamic flow rate, the source of error, the data collection and processing are closely surrounding the development process of electro-hydraulic servo valve automatic test system. Some key problems, such as the design of supporting software and the method of reducing measurement error, are studied. The main research contents include the following aspects: First of all, the influence of the electro-hydraulic servo valve on the performance of the theoretical analysis, the development of electro-hydraulic servo valve static and dynamic characteristics of the test plan, focusing on the electro-hydraulic servo valve dynamic characteristics testing principles and methods. The dynamic flow rate of servo valve is indirectly measured by measuring the moving speed of piston rod in dynamic cylinder. The frequency characteristic of electro-hydraulic servo valve is measured by two different methods: sweep frequency and spectrum analysis. Secondly, the selection of the main hardware, such as computer, data acquisition board, sensor and so on, is completed. The oil supply scheme of the test system is designed to keep the oil source stable through proportional relief valve and proportional pressure reducing valve and to absorb pressure pulsation through accumulator. Oil cleanliness is ensured by setting filters at pump outlet and valve entrance, and automatic loading of the test system is completed by proportional throttle. Thirdly, the factors affecting the dynamic characteristics of the electro-hydraulic servo valve are studied in detail: in order to satisfy the requirements of small mass, low friction and less leakage in the dynamic speed measuring cylinder. Based on the principle of minimum piston cavity, the size of dynamic speed measuring cylinder is calculated, the material and sealing scheme of dynamic speed measuring cylinder are determined, and the natural frequency of dynamic speed measuring cylinder is estimated. The mathematical model of the dynamic characteristic testing system of electro-hydraulic servo valve is established. The natural frequency and the mass of moving components are studied by Similink simulation. The influence of the two cavity volume of pipeline and cylinder and the closed loop system of position setting on the dynamic characteristic test process and result of electro-hydraulic servo valve. The rationality of the design and the feasibility of the test scheme are also verified. Finally, the method of generating excitation signal and data acquisition and processing by virtual instrument is studied. Based on the graphical programming software LabVIEW, the test system program is compiled, and the function of static and dynamic characteristic testing of electro-hydraulic servo valve is realized through the cooperation of software and hardware. The source of the error in the testing process is analyzed from the two aspects of software and hardware. Digital filtering and smoothing window are adopted in software and shielding isolation and single point grounding are adopted in hardware to reduce the measurement error.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH137.52

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