Design of Vehicle-Mounted Medical Temperature Control System

Temperature control has been widely applied in many fields, such as medical product transportation, living tissue storage and blood transfusion. Therefore, it is very important to design a vehicle-mounted medical temperature control system. The priority of the developed system must meet stability and accuracy requirement. Based on the fuzzy PID control, a system design solution was proposed in this paper. The control system includes thermal resistor used as a front end to measure temperature, AD7705 chip used as the Analogy Digital Converter (ADC), and TEC component used as the heating or the cooling unit. According to the water tank experiment, a combined control method is offered to meet the temperature control and overcome the controller's non-linearity and hysteresis. When temperature error between the set value and actual temperature value is large, the look-up table control method is used to reduce the heating or cooling time of temperature. When the error is within 1°C, the incremental PID control method is applied to decrease the overshoot. The purpose of the control system is within the range of 37±0.1°C. Meanwhile, the fuzzy PID control and BP-NN PID control algorithms have been studied and analyzed by Mat-lab simulation, which offers further improvement for system update.