输血输液加温仪的恒温控制系统设计

Design on Thermostatic Control System of Heating Instrument for Blood Transfusion and Infusion

在医用输血输液加温仪的恒温控制过程中,加热管的热传导迟滞特性导致系统的快速性和超调量无法兼顾。为解决此问题,对加热管的热传导规律进行研究,设计了一种带温升速率负反馈的PID恒温控制算法。该算法根据加热管的温升速率对PID控制作用进行动态修正,将因热传导的迟滞特性而滞留在加热管内部的热量以温升速率量化后再作为负反馈动态补偿到PID控制作用中,在邻近稳态时按一定函数衰减PID控制作用。实验结果表明,基于温升速率负反馈动态修正的PID恒温控制系统的过渡时间更短,超调量更小,稳态误差控制在±0.1℃以内。

In the process of thermostatic control of medical heating instrument for blood transfusion and infusion,the hysteresis of heat transfer of the heating tube leads that unbalance between rapidity and overshoot of the system cannot be considered.To solve this problem,the heat transfer law of the heating tube is studied,and a PID thermostatic control algorithm with negative feedback of temperature rise rate is designed.The PID control function is corrected dynamically according to the temperature rise rate of the heating tube,the heat trapped in the heating tube due to the hysteresis characteristic of heat transfer is quantified according to temperature rise rate and then dynamically compensated to the PID control function as negative feedback.The PID control function is attenuated according to a certain function when the temperature is near the steady state.The experimental results show that the PID thermostatic control system based on the negative feedback dynamic correction of temperature rise rate has short transition time,small overshoot,and the steady-state error is controlled within±0.1℃.