Design of proportional - integral (PI) controller with acceptable robustness and performance for first -order plus delay - time (FOPDT) process was introduced in this work. The delay - time part of process was approximated by 2/2 Pade, and then the PI parameters were related apparently to the closed - loop damping ratio and osil-lation frequency. After PI parameter tuned with optimal integral performance under dampimg ratio constraints, the closed - loop robustness and performance versus the damping ratio were obtained, and the expected damping ratio need to be considered with robustness and performance simultaneously. So, a cost function which was integral performance weighted by robustness was proposed, and as an example, the integrated absolute error (IAE) and the maximum sensitivity (Ms) were used to optimize the PI parameters for FOPDT process. Simulations show that the proposed PI can achieve satisfied robustness and performance for different ratio of lag time to delay time FOPDT processes, and this robust performance criteria has great significence to other controllers and/or for other processes as reference.%关于控制系统稳定性优化问题,针对一阶时滞过程(FOPDT),给出了一种鲁棒性和性能都可接受的比例积分(PI)控制器设计方法.将过程时滞部分用2/2Pade逼近后,可导出PI参数与闭环系统阻尼比和振荡频率的显示关系.在限定阻尼比下依积分性能最优整定PI后,可得到系统随阻尼比变化的积分性能和鲁棒性.根据传统方法,不可能得到稳定性能.为选择期望的阻尼比,优化系统性能,提出一种鲁棒性加权的积分性能损失函数,以绝对误差积分(IAE)和最大灵敏度(Ms)为例,对FOPDT过程的PI参数进行优化仿真.仿真结果表明,所得的PI对不同时延比的FOPDT过程均有满意的鲁棒性和稳定性,对其它控制器和过程的参数优化有很好的借鉴作用.
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