基于模糊PID控制的电阻炉炉温系统的研究.doc

北京联合大学毕业设计外文原文及译文 题目： 基于模糊PID控制的电阻炉炉温系统的研究 专业： 电气工程与自动化 指导教师： 张兆莉 学院： 自动化学院 学号： 24 班级： 0710031104 姓名： 杨京伟 1.1 INTRODUCTION From the studies of linear differential equations with constant coefficients of SISO systems, we learned that the homogeneous solution that corresponds to the transient response of the system is governed by the roots of the characteristic equation. Basically, the design of linear control systems may be regarded as a problem of arranging the location of the poles and zeros of the system transfer function such that the system well perform according to the prescribed specifications. Among the many forms of performance specifications used in design, the most important requirement is that the system must be stable. An unstable system is generally considered to be useless. When all types of systems are considered-linear, nonlinear, time-invariant, and time-varying-the definition of stability can be given in many different forms. We shall deal only with the stability of linear SISO time-invariant systems in the following discussions. For analysis and design purposes, we can classify stability as absolute stability and relative stability. Absolute stability refers to the condition whether the system is stable or unstable; it is a yes or no answer. Once the system is found to be stable, it is of interest to determine how stable it is, and this degree of stability is a measure of relative stability. In preparation for the definition of stability, we define the two following types of responses for linear time-invariant systems: Zero-state response. The zero-state response is due to the input only; all the initial conditions of the system are zero. Zero-input response. The zero-input response is due to the initial conditions only; all the inputs are zero. From the principle of superposition, when a system is subject to