流量控制继电反馈参数自整定研究  

Research on Relay Feedback Parameter Self-Tuning for Flow Control

作　　者：殷华文[1] YIN Huawen(College of Intelligent Manufacturing,Nanyang Institute of Technology,Nanyang 473004,China)

机构地区：[1]南阳理工学院智能制造学院,河南南阳473004

出　　处：《自动化仪表》2020年第6期68-72,76,共6页Process Automation Instrumentation

摘　　要：根据继电反馈理论,通过观测管道流量对象在继电反馈下的极限环振荡,进行比例积分微分(PID)算法和参数自整定技术研究。采用阶跃响应法测试对象的数学模型。管道流量是一阶非线性小惯性过程对象,时间常数小,增益变化大。由于对象的非线性,在不同的流量设定值下,控制参数鲁棒性较差,所以继电反馈振荡应在工艺点附近进行。对单极性PID调节器,通过设置继电输出中心点的方法进行继电输出,而中心点的选择应能使对象工作在工艺点附近。由于对象惯性小、易起振,所以继电输出也应较小,继电幅值d选取5%~10%。对振荡曲线在线辨识,用变量参数归一化的方法计算继电振荡时的临界增益,再根据Ziegler-Nichols公式自动计算PID控制器参数。控制过程超调量小于10%,稳态误差小于1%。通过对试验结果的分析比较可知,带滞环继电反馈参数整定方法和微分先行PID算法适用于流量控制。采用微分先行,可以防止设定值阶跃时对流量小惯性对象的冲击而产生振荡。Based on relay feedback theory,this subject through observing the limit cycle oscillation in the relay feedback of pipe flow object,research proportion integration differentiation(PID)algorithm and parameters self-tuning technology.The mathematical model of the object is tested by step response method,the pipeline flow is first order nonlinear small inertia process object with small time constant and big gain variation.Due to the nonlinearity of the object,under different flow setting values,the control parameters is poorly robustness.So relay feedback oscillation should be carried out in the vicinity of the process point.For single polarity PID controller by setting the relay output center to output relay oscillation,and the selection of relay output center should be able to work in the vicinity of the process point.Because of the small inertia of the object,it is easy to vibrate,the relay output should be small,relay amplitude d is chosen 5%~10%.According to the online identification of the oscillation curve,with variable parameter normalization method to calculate the critical gain of pipe flow object relay oscillation,and then calculate the PID controller parameters online by Ziegler-Nichols formula.Pipe flow process control overshoot volume is less than 10%,the steady-state error is less than 1%.Through analysis and comparison of experimental results,with hysteresis relay feedback parameter setting method and derivative ahead PID algorithm is suitable for flow control.Using differential forward can prevent settings step impact on flow object with a small inertia and produce oscillation.

关 键 词：流量控制 小惯性非线性过程 滞环继电反馈 单极性PID 继电输出中心点 变量参数归一化 自整定算法 微分先行 

分 类 号：TH7[机械工程—仪器科学与技术]