Panda Rames C, Yu Cheng-Ching, Huang Hsiao-Ping
Department of Chemical Engineering, National Taiwan University, Taipei 106-17, Taiwan.
ISA Trans. 2004 Apr;43(2):283-95. doi: 10.1016/s0019-0578(07)60037-8.
PID controllers are widely used in industries and so many tuning rules have been proposed over the past 50 years that users are often lost in the jungle of tuning formulas. Moreover, unlike PI control, different control laws and structures of implementation further complicate the use of the PID controller. In this work, five different tuning rules are taken for study to control second-order plus dead time systems with wide ranges of damping coefficients and dead time to time constant ratios (D/tau). Four of them are based on IMC design with different types of approximations on dead time and the other on desired closed-loop specifications (i.e., specified forward transfer function). The method of handling dead time in the IMC type of design is important especially for systems with large D/tau ratios. A systematic approach was followed to evaluate the performance of controllers. The regions of applicability of suitable tuning rules are highlighted and recommendations are also given. It turns out that IMC designed with the Maclaurin series expansion type PID is a better choice for both set point and load changes for systems with D/tau greater than 1. For systems with D/tau less than 1, the desired closed-loop specification approach is favored.
PID控制器在工业中广泛应用，在过去50年里人们提出了众多整定规则，这常常让用户迷失在整定公式的丛林中。此外，与PI控制不同，PID控制器不同的控制律和实现结构使其使用更加复杂。在这项工作中，选取了五种不同的整定规则来研究控制具有广泛阻尼系数以及死区时间与时间常数比（D/τ）的二阶加纯滞后系统。其中四种基于内模控制（IMC）设计，对死区时间采用了不同类型的近似，另一种基于期望的闭环规格（即指定的前向传递函数）。在IMC类型设计中处理死区时间的方法尤为重要，特别是对于D/τ比值较大的系统。采用了一种系统的方法来评估控制器的性能。突出了合适整定规则的适用范围，并给出了相关建议。结果表明，对于D/τ大于1的系统，采用麦克劳林级数展开型PID设计的IMC对于设定值和负载变化都是更好的选择。对于D/τ小于1的系统，更倾向于采用期望的闭环规格方法。
