不稳定时滞对象的串级控制设计

Cascade Control Design for Unstable Process With Time Delay

针对常见的开环不稳定串级过程,提出一种新的解析设计方法。副回路中采用两自由度内模控制结构,减少因副回路设定值响应与扰动抑制响应耦合对主回路性能的影响。主回路采用加滤波器的单位反馈控制结构,基于闭环最优灵敏度函数解析推导出设定值响应控制器,保证系统的整体性能。针对副回路存在的乘性不确定性,分析了系统的鲁棒稳定性,最后通过仿真验证了该控制方案的有效性。

A new analytical design method is proposed for unstable cascade processes.Two-degree-of-freedom internal mode control is adopted to reduce the influence on performance of primary loop because of the coupling between the set-point tracking and disturbance rejection in the secondary loop.The structure of unity feedback introduced low-pass filter is used in the major loop,and the major controller is derived based on the closed-loop sensitivity function,which guarantees a good system performance.The control system robust stability is analyzed in the presence of the process multiplicative uncertainty in the minor loop.Finally,simulation example demonstrates the validity of the proposed control scheme.