设定值滤波型四参数二自由度PID算法研究

Research on Setpoint Filtering Four-Parameter Two-Degree-of-Freedom PID Algorithm

对设定值滤波型二自由度比例积分微分(PID)算法进行研究。二自由度PID相当于两个调节器的串联。第一个调节器是设定值滤波器,对设定值阶跃作衰减和惯性滤波,相当于对设定值作了一次比例积分(PI)调节。第二个调节器是对系统偏差作了一次微分先行PID调节。控制参数包含PID控制器的K_(p)、T_(i)、T_(d)和滤波系数α共四个参数。两个调节器共用一个积分参数T_(i)。用二自由度PID算法分别对水泵压力、管道流量、水箱液位和锅炉温度对象进行控制试验研究,总结出控制参数随对象惯性大小而设置的规律,即:惯性大则K_(p)和α取大值使得设定值滤波器和PID运算输出增大,反之则减小。和一自由度PID相比,二自由度PID能实现设定值跟随和扰动抑制的双优控制。

The setpoint filtered two-degree-of-freedom proportional integral differential(PID)algorithm is investigated.The two-degree-of-freedom PID is equivalent to the series connection of two regulators.The first regulator is a setpoint filter,which attenuates and inertially filters the setpoint step,which is equivalent to a proportional integral(PI)adjustment of the setpoint.The second regulator is a differential prior PID regulation of the system deviation.The control parameters include four parameters K_(p),T_(i),T_(d) and filter coefficientαof the PID controller.The two regulators share an integral parameter T_(i).The two-degree-of-freedom PID algorithm is used to control the pump pressure,pipe flow,tank level and boiler temperature objects respectively,and concludes that the control parameters are set according to the inertia of the objects,i.e.,if the inertia is large,K_(p) andαtake large values to make the set value filter and PID operation output increase,and vice versa to decrease.Compared with the one-degree-of-freedom PID,the two-degree-of-freedom PID can realize the double-optimal control of set value following and disturbance suppression.