静脉输液过程中滴速自动控制系统的建模与仿真

Modeling and Simulation of an Automatic Drip Rate Control System on Intravenous Infusion Process

为对静脉输液过程的滴速自动控制系统进行设计和分析,对此类型系统进行建模和仿真研究;通过实验数据拟合出输液过程的静态模型,进而得到非线性的动态模型;采用一阶惯性环节对执行机构的动态特性进行描述,采用定积分对基于红外光电对管的滴速检测环节进行建模;在静态工作点对过程模型进行基于增量法的近似线性化处理,对给定值小范围变化的情况设计了PID控制律,对给定值大范围变化的情况采用先开环控制后闭环控制的控制策略;仿真结果表明,该模型能较准确反映被控过程和控制系统的特性,对控制系统的实施有较好的参考价值。

To design and analyze an automatic drip rate control system on intravenous infusion process, this paper carried out researches on system modeling and simulation. A static model of the process, which was then used to calculate a nonlinear dynamic model, was obtained by experimental data after curve fitting. A first--order inertial element was utilized to depict the dynamics of the control element, while the infrared--photoelectric--based drip rate detection element was represented by a definite integral model. The process model was approximately linearized on quiescent operating points by incremental method, then a PID control law was designed for the case of small setting value changes while an open--loop--ahead closed loop strategy was presented for the case of large setting value changes. The simula- tion results showed the presented model could reflect the actual characteristics of the controlled process and control system, which was a good reference to implementation of the control system.