高精度无源电阻发生器的研究

发布时间：2019-04-04 10:40

【摘要】：电阻发生器作为仪器仪表校准、电路测试等领域的重要基准源,广泛应用于汽车及航空仪表调校、万用表的阻抗测试以及电子电路调试等场合。目前,电阻发生技术主要包括有源和无源两种。其中,有源电阻发生技术功耗大且易干扰外部电路,因而在小功率仪表检测应用场合,更多地采用无源电阻发生技术,其原理简单易于实现,但无源电阻发生器在输出精度和稳定性方面尚存在不足。因此,对高精度无源电阻发生器的研究是亟需解决的问题。针对以上问题,本文提出一种高精度无源电阻发生器的研究。系统以ARM作为主控单元控制继电器切换实现无源电阻输出,通过与高精度万用表通信完成系统校准功能,并采用LCD显示模块和触摸转换芯片实现软件界面显示、用户操作的识别和响应功能。通过分析影响系统输出性能的硬件因素及其影响规律,采用模拟实际电阻输出的方法,确定各影响因素综合作用下电阻组合与其实际输出电阻值的定量关系,建立电阻输出模拟方程;分别采用广度优先搜索算法和分支定界算法对模拟方程进行求解,获取实际输出值最接近设定电阻值的最优电阻组合,通过对两种算法时间复杂度的对比分析,确定广度优先搜索算法作为最优电阻组合求解算法;基于GUI图形界面库开发下位机软件,通过人机交互单元识别并响应用户操作,完成下位机软件对电阻发生器的控制功能;基于Visual Studio2010开发环境,采用C#语言进行上位机软件设计,通过USB HID通信协议,完成上位机软件与电阻发生器的信息交互,从而通过上位机或下位机等两种方式实现无源电阻输出、系统校准、信息监控等功能,满足用户对电阻发生器的控制需求,达到良好的人机交互性能。通过无源电阻发生器的性能测试,实验结果表明:系统在实现1.0?~20 k?的输出范围、0.1?分辨力(1 k?以内,1 k?以上分辨力为1?)的技术指标下,在1.0?~11.0?输出范围内,系统输出最大相对误差为2.4%,11.1?~12 k?输出范围内,系统输出最大相对误差为0.8%,12 k?~20 k?输出范围内,系统输出最大相对误差为0.029%,系统响应时间优于500ms;系统输出值具有良好的重复性;且能够有效减小器件老化对系统输出准确度的影响,具有一定的稳定性。因此,该无源电阻发生器解决了现有无源电阻发生技术存在的输出精度低和稳定性差等问题,为高精度无源电阻输出提供一种新方法,具有较高的工程应用价值。
[Abstract]:As an important reference in the field of instrument calibration and circuit testing, resistance generator is widely used in automotive and aeronautical instrument adjustment, impedance test of multimeter and electronic circuit debugging and so on. At present, resistance generation technology mainly includes active and passive. Among them, active resistance generation technology has a large power consumption and is easy to interfere with external circuits. Therefore, passive resistance generation technology is more widely used in low power instrument detection applications, and its principle is simple and easy to realize. But the output precision and stability of passive resistance generator are still insufficient. Therefore, the research of high precision passive resistance generator is an urgent problem to be solved. In order to solve the above problems, a high precision passive resistance generator is proposed in this paper. The system uses ARM as the main control unit to control relay switch to realize passive resistance output. The system calibration function is completed by communicating with the high precision multimeter, and the software interface display is realized by using LCD display module and touch conversion chip. User action identification and response function. By analyzing the hardware factors affecting the output performance of the system and its influence rules, the quantitative relationship between the combination of the resistors and their actual output resistance values under the comprehensive action of each influence factor is determined by using the method of simulating the actual resistance output. The simulation equation of resistance output is established. The simulation equation is solved by breadth-first search algorithm and branch-bound algorithm respectively, and the optimal resistance combination with actual output value closest to the set resistance value is obtained, and the time complexity of the two algorithms is analyzed by comparing the time complexity of the two algorithms. Determine the breadth-first search algorithm as the optimal resistance combination algorithm; The software of lower computer is developed based on GUI graphic interface library. Through the identification and response of user operation by man-machine interaction unit, the control function of lower computer software to resistance generator is completed. Based on the Visual Studio2010 development environment, the upper computer software is designed with C # language. Through the communication protocol of USB HID, the information interaction between the upper computer software and the resistance generator is completed. So the passive resistance output, system calibration, information monitoring and other functions can be realized by the upper computer or the lower computer, which can meet the control requirements of the resistance generator and achieve good human-computer interaction performance. Through the performance test of the passive resistance generator, the experimental results show that the system is realized in the range of 1.0 ~ 20 km ~ (- 1). Output range, 0.1? Resolution (1 k? Within, 1 k? The above resolution is 1?) Under the technical index of 1.0? In the output range, the maximum relative error of the system output is 2.4%, 11.1 / 12k? Within the output range, the maximum relative error of the system output is 0.8%, and the maximum output error of the system is 12 kg / 20 kg? In the output range, the maximum relative error of the system output is 0.029%, the response time of the system is better than 500 Ms, and the output value of the system has good repeatability. And it can effectively reduce the influence of device aging on the system output accuracy, and has a certain stability. Therefore, the passive resistance generator solves the problems of low output precision and poor stability in the existing passive resistance generation technology, and provides a new method for high precision passive resistance output, which has high engineering application value.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM54

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