基于DSP的高精度信号发生器设计及其在机械测试中的应用

发布时间：2018-06-29 09:56

本文选题：机械测试 + 激励信号　；参考：《河北农业大学》2014年硕士论文

【摘要】：机械装备的可靠性是故障诊断和设备监测中研究的重要课题。随着科技水平的不断提高，机械设备的系统越来越庞大，各部分之间的联系也越来越紧密，其中某个零件的故障都可能会引起整个系统的停滞，给企业或国家带来巨大的损失。因此，设备的检测和故障诊断对于安全生产，民生来说非常重要。在机械工程中对一些重要部件（主轴，机床底座等）进行可靠性测试时，经常需要激振器来产生激励信号，测试机械运行中的振动量是否对机械的使用寿命和正常运转造成影响。除此之外，在一些振动试验建模中也很重要。在机械测试中经常会用到各种激励信号，因此，本课题研发了以DSP为核心的数字信号发生器系统，系统由CPU模块、D/A输出模块，存储模块，无线通信模块等组成。OMPL138芯片是TI公司的近几年刚推出的一款采用达芬奇构架的处理器，包括ARM9和C674x系列的DSP，两大CPU为采用非对称式达芬奇结构的低功耗处理器，兼具DSP的高速数字信号处理性能和ARM9精简指令计算机（RISC）技术的优点。系统的主要实现过程为：利用DSP的高速数据处理能力对信号代码复杂算法进行运算处理，产生的波形数据储存在发送数据缓存区；再利用EDMA（Enhanced Direct Memory Access快速直接内存存取）技术对数据进行搬运，传送到McASP（多通道音频串行端口）的发送端，，然后以IIS的方式传送到D/A芯片进行滤波放大等处理输出。本系统可以产生标准的正弦波，三角波，方波，窄带随机，白噪声五种波形，满足了机械测试需要。同时，还可以对正弦波、三角波、方波进行扫频和扫幅，输出电压范围为-10V~+10V。其中正弦波的失真度能达到0.0064%频率精度达到10-7，能够适用于大多数的机械振动测试实验要求。本文在正弦波、三角波、方波和白噪声等信号理论的基础上，以DSP为核心，进行了硬件设计和软件设计。其中，硬件设计包括CPU复位电路设计、D/A数模转换电路设计、WIFI电路设计和电源电路设计；软件设计包括：McASP和EDMA的通信设计以及信号代码的编写；最后进行系统的调试和测试等工作。测试试验表明，系统满足大多数的测试要求。论文中的主要工作如下： 1.采用DSP作为数据的处理核心，充分利用DSP的高速数据运算能力，能够有效地对波形代码中的复杂算法进行快速运算，从而有效的产生波形； 2.采用函数计算生成波形数据的方法，舍弃了传统的模拟电路和DDS（直接数字合成）芯片生成波形的方法，采用函数计算生成波形数据的方法，不仅精度高能达到10-7，而且还降低了系统硬件上的设计成本； 3.采用EDMA（增强型直接内存存取）传输数据，充分利用EDMA独立于CPU的后台批量数据传输的能力，不占用CPU的资源，从而能使DSP专注于数据的处理； 4.为了验证所研发信号发生器的频率精度和失真度，试验测试得到了100Hz正弦波各项参数。测试结果，波形的失真度为0.0077%，频率精度为3E-6，幅值精度为1.8E-3。并将该系统在机械测试工程中进行了试验研究，在隔振台上进行了模态测试，达到了测试要求。
[Abstract]:The reliability of mechanical equipment is an important subject in fault diagnosis and equipment monitoring. With the continuous improvement of the level of science and technology, the system of mechanical equipment is becoming more and more large, and the connection between the parts is becoming more and more close. One part of the fault may cause the stagnation of the whole system and bring huge loss to the enterprise or the country. Therefore, equipment detection and fault diagnosis are very important for safety production and people's livelihood.
In the reliability test of some important parts (spindle, machine base, etc.) in mechanical engineering, it is often needed to generate exciting signals to determine whether the vibration in the mechanical operation affects the service life and normal operation of the machine. In addition, it is also important in some vibration test modeling. All kinds of incentive signals are often used. Therefore, we developed a digital signal generator system with DSP as the core. The system consists of CPU module, D/A output module, storage module, wireless communication module and so on. The.OMPL138 chip is a processor which has been introduced by TI in recent years, including the DSP of ARM9 and C674x series. The two CPU is a low power processor with asymmetrical Da Vinci structure. It has the advantages of DSP's high speed digital signal processing performance and the ARM9 simplification instruction computer (RISC) technology.
The main process of the system is as follows: using the high speed data processing capability of DSP to process the complex algorithm of signal code, the generated waveform data is stored in the data cache, and then the EDMA (Enhanced Direct Memory Access fast direct memory access) technology is carried to the McASP (multichannel audio string). The transmission end of the line is transmitted to the D/A chip in the way of IIS. The system can produce a standard sine wave, triangular wave, square wave, narrow band random, white noise five waveforms, which satisfy the requirement of the mechanical test. At the same time, the sine wave, the triangle wave and the square wave can be swept and swept, and the output voltage model can be used. Surrounded by -10V~+10V., the distortion of sine wave can reach 0.0064%, and the frequency accuracy reaches 10-7, which can be applied to most mechanical vibration test requirements.
On the basis of sine wave, triangle wave, square wave and white noise and so on, the hardware design and software design are carried out with DSP as the core. The hardware design includes the CPU reset circuit design, the D/A digital analog conversion circuit design, the WIFI circuit design and the power circuit design. The software design includes the communication design of McASP and EDMA and the design of the communication. Finally, the debugging and testing of the system are carried out. The test results show that the system meets most of the test requirements.
The main work in this paper is as follows:
1. using DSP as the core of data processing, making full use of the high speed data operation ability of DSP, can effectively calculate the complex algorithm in the waveform code, and effectively generate the waveform.
2. the method of generating waveform data by function calculation, the method of generating waveform from traditional analog circuit and DDS (direct digital synthesis) chip is abandoned. The method of generating waveform data by function calculation is not only high and high energy is reached 10-7, but also the design cost of system hardware is also reduced.
3. use EDMA (enhanced direct memory access) to transmit data, make full use of the ability of EDMA to transmit data in the background of CPU, and do not occupy the resources of CPU, so that DSP can concentrate on the processing of data.
4. in order to verify the frequency accuracy and distortion of the developed signal generator, the 100Hz sine wave parameters are obtained by test and test. The result shows that the distortion of the waveform is 0.0077%, the frequency accuracy is 3E-6, the amplitude precision is 1.8E-3., and the system is tested in the mechanical test engineering, and the modal test is carried out on the vibration isolation platform. It's the test requirements.
【学位授予单位】：河北农业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP332

【参考文献】