【作者】 孙娜；

【导师】 袁爱进；

【作者基本信息】 大连交通大学 ， 控制理论与控制工程， 2007， 硕士

【摘要】 PID控制是迄今为止最通用的控制方法。调查结果表明，90％以上控制回路中均采用自整定PID控制器。因此，PID控制器参数自整定技术是一门集自适应控制、智能控制、自动化过程控制为一体的高科技工程新技术，是当前十分热门的研究课题之一。然而由于被控对象参数变化，PID控制器参数也要随之变化，才能更好地控制被控对象，因此控制模型的辨识成为一个关键问题。基于频率特性的PID控制器参数自整定方法(SF法)是针对工程上常用的Z-N法与继电反馈法在获取临界周期Tc和临界增益Kc时可能会给系统带来扰动而提出的。该算法的创新之处在于它是基于连续频谱的识别，应用FFT进行时频序列转换然后在频域内建模。虽然该算法已在MATLAB中得到了仿真结果，但算法仍存在着一些不足，如导致频谱失真的主要误差因素-能量泄漏问题；重复性差及MATLAB仿真无法满足实时性要求等问题。本文针对上述问题，提出R(refine)-SF法，该算法在FFT(快速傅里叶)之前采用高通滤波来滤除信号的低频部分，使信号变化比较平稳的低频部分为零，再对其截断时，就避免了能量泄漏问题。同时巧妙地利用频率特性表达式中的除法将分子Y(jω)与分母X(jω)中混有的相同滤波器频谱消去。对重复性问题的研究发现是微分控制引起被控对象的输入信号峰值尖锐，在对其采样时的“栅栏效应”引起的误差。本文在LabVIEW平台下，通过OPC服务器连接下位机，使整个程序全部由LabVIEW和智能仪表的实时运算来实现，从而满足了实时性的要求。在实时系统中的实验结果表明，该算法求得的被控对象的频率特性与真实值相近，可以应用到需要求解被控对象频率特性的其他PID参数整定方法中。因此，该方法具有一定的推广应用价值。更多还原

【Abstract】 Self-tuning PID controller has been widely used in industrial proceeding control,research result shows that more than 90 percent control circuits make use of self-tuning PID controller. The PID controller parameters self-tuning technique is a new technique in high—tech engineering for gathering from orientation controlling, intelligence control, automating process control, is one of the current very popular research problems. However, because of parameter changes of controlled object,the parameter of PID controller also changes immediately, then it can better control the controlled object, therefore recognition of controlled object become a key problem.Aim at the problem of getting vibrating period and amplitude in methods of Z-N method and relay-tuning method, referring a algorithm of PID controllers parameters self-tuning based on frequency characteristic. The benefits to this algorithm is based on the identification of continuous spectrum, time-frequency conversion and modeling using FFT.Although the algorithm has been in the MATLAB simulation,but it has some shortcomings,such as energy leakage,which is the major factors leading to distortion of the spectrum; poor repeatability and poor real time.In this paper we refer a R(refine)-SF algorithm,it use a high-pass filter to filt lower frequency before of FFT.High-pass filter can make the low frequency part of signal equal zero,then the algorithm avoid energy leakage.Meanwhile use skilfully the nature of devide in the expression of frequency charactistic to eliminate the errors of frequency of filter in the denominator and nominator. On the poor repeatability found that differential controller cause input signal sharp amplitude, which cause the error when sampled.This paper communicate data between the smart meters and LabVIEW through OPC server as a bridge, and the whole process is controlled real-timely by LabVIEW and the smart meters to meet the requirment of real-time.The experimental results in the real-time system show that the frequency of object in this algorithm close to the real value,this method can applicate in other PID parameters tuning method. Therefore,this method has some promotional value.更多还原