基于虚拟仪器的伺服机构谐振频率测试系统研制

发布时间：2018-04-16 08:17

本文选题：伺服机构 + 谐振频率　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：谐振频率测试是伺服系统动态特性测试的重要内容。本文选题来源于国防预研项目,以导引头伺服机构为测试对象,它具有体积小、结构复杂、被测特性参数数量级较小等特点,用非电测的方法进行测量,其精度低,实施性差。本文应用虚拟仪器技术构建的自动化测试系统,充分发挥了计算机在数值计算和图形处理等方面的强大功能,在一台微机上就可以完成整套测试流程,提高了开发效率和测试效率,简化了工程测试操作,增强了系统的灵活性,同时降低了测试成本。实验证明,本文设计的谐振频率测试系统操作简单、界面友好,可以指导加工装配和故障诊断,具有一定的实际使用价值。本文主要工作及创造性成果如下:1.以电机-负载系统为模型,对其进行动态特性分析。介绍了伺服系统的组成及工作原理,建立了伺服系统的数学模型,推导出系统的传递函数,并对其进行动态特性分析,从而得出影响谐振频率的两个关键要素:系统的刚度和转动惯量。2.对谐振频率的测试原理和测试方法进行了研究。从计算法和实验法两方面入手,详细介绍了谐振频率测试的原理和方法。计算法提出,在已知电机和负载转动惯量的情况下,通过绘制系统的扭转-变形图得到系统的刚度,再由公式?=K/J求出谐振频率。实验法介绍了稳态激振法和瞬态激振法:稳态激振法通过系统的频率特性曲线,得到谐振频率;瞬态激振法让电机突然启动到制动的过程中,会发生衰减振荡,根据振荡周期可以反推出谐振频率。3.针对导引头伺服机构的特点,设计了谐振频率测试系统的总体方案,进行了硬件选型,设计了RDC解码电路。4.论述了软件的设计方案和功能需求,以LabVIEW为开发工具,通过编程实现了串口通信、数据处理、数据保存、打印报表等功能于一体的上位机软件,利用多轴运动卡编程语言开发了信号产生及数据采集的下位机软件,并对软件界面分模块进行了介绍。5.由于采集到的信号中含有噪声干扰,着重分析了小波降噪原理及在Lab VIEW中如何实现。同时,对数据处理算法进行了介绍。6.在测试系统搭建好之后,进行软硬件调试,对采集到的信号进行数据处理,通过快速傅里叶变换和功率谱算法得到系统的频率特性曲线,由频率特性曲线得到导引头伺服机构的谐振频率。测试结果表明,研制的自动化测试系统可以准确的测量导引头伺服机构的谐振频率,同时也论证了测试方案的可行性、测试方法及数据处理方法的正确性和可靠性。
[Abstract]:Resonant frequency measurement is an important part of servo system dynamic characteristic test.This thesis comes from the national defense pre-research project, takes the seeker servo mechanism as the test object, it has the characteristics of small volume, complex structure and small order of magnitude of the parameters to be measured. The method of non-electric measurement is used to measure, its precision is low, and the performance is poor.The automatic test system based on virtual instrument technology has brought into full play the powerful functions of computer in numerical calculation and graph processing, and the whole test flow can be completed on one microcomputer.The development efficiency and test efficiency are improved, the engineering test operation is simplified, the flexibility of the system is enhanced, and the test cost is reduced.Experimental results show that the resonant frequency testing system designed in this paper is simple in operation, friendly in interface, and can guide machining assembly and fault diagnosis, and has certain practical application value.The main work and creative achievements of this paper are as follows: 1.The dynamic characteristics of the motor-load system are analyzed.This paper introduces the composition and working principle of the servo system, establishes the mathematical model of the servo system, deduces the transfer function of the system, and analyzes the dynamic characteristics of the servo system.Thus, two key factors affecting the resonant frequency are obtained: stiffness and moment of inertia of the system.The measuring principle and method of resonant frequency are studied.The principle and method of resonant frequency measurement are introduced in detail from two aspects of calculation method and experimental method.In the case of known moment of inertia of the motor and load, the stiffness of the system is obtained by drawing the torsional deformation diagram of the system, and the resonant frequency is calculated by the formula K / J.The experimental method introduces the steady-state excitation method and the transient excitation method: the steady-state excitation method obtains the resonant frequency through the frequency characteristic curve of the system, the transient excitation method makes the motor suddenly start up to the braking process, and the attenuation oscillation occurs.The resonant frequency. 3.According to the characteristics of servo mechanism of seeker, the overall scheme of resonant frequency testing system is designed, the hardware selection is carried out, and the RDC decoding circuit .4.This paper discusses the design scheme and function requirement of the software. With LabVIEW as the development tool, the upper computer software with the functions of serial communication, data processing, data saving, report printing and so on is realized by programming.The lower computer software for signal generation and data acquisition is developed by using multi-axis motion card programming language, and the interface module of the software is introduced.The principle of wavelet noise reduction and how to realize it in Lab VIEW are analyzed because of the noise interference in the collected signal.At the same time, the data processing algorithm is introduced. 6.After the test system is set up, the software and hardware are debugged, the collected signals are processed, and the frequency characteristic curves of the system are obtained by fast Fourier transform and power spectrum algorithm.The resonant frequency of the seeker servo mechanism is obtained from the frequency characteristic curve.The test results show that the developed automatic test system can accurately measure the resonant frequency of the seeker servo mechanism. At the same time, the feasibility of the test scheme, the correctness and reliability of the test method and the data processing method are also demonstrated.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM935.1

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