【作者】 王巧云；

【导师】 曾良才；

【作者基本信息】 武汉科技大学 ， 机械电子工程， 2004， 硕士

【摘要】 电液伺服系统是一结构复杂而多耦合的机、电、液综合系统，是控制领域中的一个重要组成部分，具有功率大，响应快，精度高的特点，在工业生产领域得到了广泛的应用。而电液伺服阀是电液伺服系统的关键性元件，是系统中故障率最高的部位，其使用情况与性能的好坏直接影响到系统的工作性能。因此，研究一种切实可行的故障智能诊断方法，对电液伺服阀可能发生的故障进行预报、控制，对已发生的故障进行正确而迅速的智能诊断，提供可行的排除方法十分重要。 本文以电液伺服阀静、动态特性试验台为依托，在广泛研究国内外相关文献资料及工作的基础上，结合现代故障诊断理论、模式识别理论、人工智能理论和计算机科学，对动圈式电液伺服阀的故障智能诊断技术进行了较为深入的研究。 1．对电液伺服阀进行了抗污染研究。针对其先导级固定节流小孔易于堵塞的缺点，本文利用仿真软件AMESim建立了该阀的结构化的仿真模型，在改变节流孔大小、给节流孔串联和并联一个节流孔的情况下进行仿真，通过对特性曲线分析得出在阀体上开一个节流小孔，使之与固定节流小孔串联，并把两者的直径加大可以达到与原结构相同的性能，这样便可以适当提高该阀的抗污染能力。 2．对动圈式电液伺服阀的主要故障的机理进行了研究。故障机理被认为是故障诊断领域的“深知识”，研究故障机理是进行故障诊断的重要环节，本论文研究了动圈阀的主要故障模式—磨损、气蚀、液压卡紧、温升等的机理，探讨了减少动圈阀的各种故障模式的措施，分析了热楔效应对动圈阀性能的影响。 3．结合本实验室的实验条件对动圈式电液伺服阀进行了故障模拟实验：利用数字化电液伺服阀试验台，在系统压力为2MPa、2.5MPa、3MPa、3.5MPa、4MPa、4.5Mpa、5MPa时，分别测得电液伺服阀七种状态(正常、上下调零弹簧疲劳断裂、导阀一端固定节流孔堵塞、控制腔一端密封破损1／12，1／2与完全破损)下静态(压力特性曲线)特性曲线作为伺服阀的状态特征参数，并对得到的压力特性曲线进行了离散化处理。 4．建立了动圈式电液伺服阀故障智能诊断的网络模型。利用遗传算法和神经网络的特点和优点，将两者结合在一起而形成了GA-BP算法，并建立了用于电液伺服阀故障智能诊断的遗传—神经网络模型。该模型继承了传统遗传算法的优点，兼具神经网络强大的函数逼近功能，同时又克服了传统神经网络优化方法易陷入局部最优解的缺陷。实例的训练和模式识别结果表明：实数编码的遗传算法优化的神经网络模型模式识别精度较高，适合于电液伺服阀的故障模式识别。 5．在以上理论研究的基础上，利用面向对象、可视化的编程语言Visual Basic开发了基于遗传—神经网络的电液伺服阀智能故障诊断的系统。它包括知识库的建立和维护模块、推理和仿真模块等。更多还原

【Abstract】 The electro-hydraulic servo system is a complex structure and much coupled system ,which synthesized the merit of the mechanical technology , electric technology and hydraulic technology and has been an important component in the control field. The system possesses some important features, such as great power, quick response, and high precision and so on, it has widely been used in the field of the industrial product And the electro-hydraulic servo valve is a key component for the system, which is the position with a highest fault rate in the system, its using condition and performance is bad or not directly influences the system performance. Consequently, the important problem now is how to research a really feasible method for intelligent fault diagnosis and use this method to predict , control the potential fault of the electro-hydraulic servo valve or rightly and quickly diagnose the happened fault and support the feasible method for elimination the happened fault.This paper studies in depth the key technology of the electro-hydraulic servo valve, on the base of collecting broadly the relate literature and works, combined with the theories of modern fault diagnosis , recognizing the fault model , artificial intelligence and computer science, which relies on a new kind electric-hydraulic static-dynamistic character test station.1. Antipollution research of the electro-hydraulic servo valve is proposed. The antipollution capability of electro-hydraulic servo valve is not well for the sake of its pilot valve’s fixed throttle. In general, the fixed throttle’s diameter is too small and is easily to be jammed. In the paper, the author establishes the electro-hydraulic servo valve’s simulation model by using the software AMESim. We simulate by changing the two fixed throttle diameter and adding two throttle separately in series with the fixed two throttle and adding two throttle separately in parallel with the fixed two throttle. By analyzing the simulation curves , we can draw a conclusion as follows: the capability antipollution of the valve can be improved by adding a throttle in front of the fixed throttle and increasing their diameter.2. The main fault mechanism of the electro-hydraulic servo valve is studied. The fault mechanism has been considered as the "deep knowledge" in the field of fault diagnosis. The study of the fault mechanism has been a key step for the fault diagnosis. The fault mechanism of the electro-hydraulic servo valve’s main fault models, such as wearing , cavitation erosion, hydraulic lock, temperature rise and so on in this paper are studied , the measures to reduce all kinds of fault models of the electro-hydraulic servo valve are discussed and the thermal stress on how to affect the performances of the electro-hydraulic servo valve is analyzed.3. The fault simulation testing for the electro-hydraulic servo valve combined with thecondition of our lab is done. By using digital electric-hydraulic servo valve’s test station, on the pressures of system such as 2MPa, 2.5MPa, SMPa, 3 .SMPa, 4MPa, 4.5MPa, SMPa, we can measure static character carves (pressure gain) of servo valve as the static characteristic parameters, in seven conditions of electric-hydraulic servo valve (normal condition , up or down springs fatigue fracture, one side of fixed throttle hole of the pilot valve being blocked , one side of seal of bearer of control chamber being damaged 1/12, 1/2 and wholly. In order to meet the neural network model’s input requirements, at first the author processes the pressure gain curves, and then makes the discrete data between -1 and 1.4. The intelligent fault diagnosis’ network framework for the electro-hydraulic servo valve is established. In this paper, the author combines an artificial neural network with the genetic algorithms and forms a new algorithm, GA-BP algorithm, and establishes a GA-ANN model for the intelligent fault diagnosis of the electro-hydraulic servo valve, which is used the features and virtues of ANN and GA. The model takes the advantages of traditi更多还原