线性自抗扰控制的抗饱和补偿措施

控制输入约束是实际工业过程中普遍存在的现象,然而控制器设计中通常都假设执行机构动态是线性的,因此当执行机构存在约束时,执行机构输出信号与控制器输出信号不一致,使系统的动态性能降低,甚至导致系统不稳定.本文针对线性自抗扰控制(linearactive disturbance rejection control,LADRC)执行机构的约束问题,提出两种抗饱和补偿方案,利用LADRC扩张状态观测器估计控制器状态或者控制器输出与执行器输出的误差,从而使LADRC能快速消除饱和.将这两种方法用到含执行机构饱和的一阶惯性加迟延被控对象进行仿真研究,结果表明两种补偿措施下线性自抗扰控制器能得到较好的控制性能.随后本文将LADRC抗饱和思想推广到负荷频率控制系统(load frequency control,LFC)中,仿真表明基于误差补偿的抗饱和方案对于LFC系统更为有效.

Anti-windup schemes for linear active disturbance rejection control

Control input constraints are very common in industrial process, however, conventional controller design methods usually assume that the actuator dynamics is linear. Therefore, when there are constraints in the actuator, the output signal of the actuator is not consistent with the output signal of the controller, which leads to reduced control performance, even system instability. Two anti-windup schemes are proposed in this paper for linear active disturbance rejection controller (LADRC) when there are constraints in the actuator. The schemes utilize the extended state observer (ESO) to estimate the states of the controller or the error between the controller output and actuator output, so LADRC can eliminate the error quickly. Simulation study is carried out for a first order plus dead time process with actuator constraints. The results show that both schemes can achieve good anti-windup performance. Then the idea is extended to the load frequency control (LFC) system using LADRC. Simulation shows that the error-compensation-based anti-windup scheme is more effective in LFC.