On Computing Stabilizing Digital PID Controllers

• Main Author: 黃國偉
• Other Authors: Chiy Hwang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/56050927027150124801

碩士 === 國立中正大學 === 化學工程研究所 === 90 === Although the PID control algorithm is old, it is still widely used in a variety of industrial control systems. The longstanding use of PID controllers lies in the facts that the principle of PID algorithm is easy to understand and the control performance is satisfactory for a wide class of processes. Moreover, simplicity of implementation is also one of the reasons why PID controller remains the most popular approach for industrial process control despite continual advances in control theory. This is particularly true after the advent of digital computers and/or microprocessors. With the availability of low-cost programmable microprocessors, the implementation and tuning of PID control algorithm becomes advantageously flexible. This paper is concerned with the problem of determining the set of PID controller gains that can stabilize a given nth-order discrete-time plant. An analytic characterization of the stability-domain boundary in the controller gain space is derived. The idea for this stability-domain boundary characterization is taken from the field of parametric evaluation of mean-squared-errors for discrete-time systems. The proposed approach is simpler than that recently proposed by Xu et al., which utilizes a continuous-time version of Hermite-Biehler theorem along with the bilinear transformation. To illustrate the proposed approach, a numerical example is provided.