In surgery operations, wound should be cleaned with warm sterilized saline solution. In order to reach rapidly warming the washing solution from the room temperature during the surgery, we designed a thermostatic medical infusion pump. The present paper mainly presents researches on the two temperature control methods in the standby mode and in the flushing mode of the system. In the standby mode, the traditional proportional-integral-derivative (PID) control algorithm was adopted. In the flushing mode, dynamic characteristics of the system was changed in real time, which made the thermostatic control process more complex, and the fitted control function combined with the PID control algorithm was adopted in this mode. The temperature control parameters were adjusted in real time according to the initial temperature and the flow rate of the washing solution to obtain a constant temperature of the washing solution, no matter how the initial temperature and the flow rate are changed. The experiment results showed that this kind of control system performed well with a high accuracy.
Robotic catheter minimally invasive operation requires that the driver control system has the advantages of quick response, strong anti-jamming and real-time tracking of target trajectory. Since the catheter parameters of itself and movement environment and other factors continuously change, when the driver is controlled using traditional proportional-integral-derivative (PID), the controller gain becomes fixed once the PID parameters are set. It can not change with the change of the parameters of the object and environmental disturbance so that its change affects the position tracking accuracy, and may bring a large overshoot endangering patients' vessel. Therefore, this paper adopts fuzzy PID control method to adjust PID gain parameters in the tracking process in order to improve the system anti-interference ability, dynamic performance and tracking accuracy. The simulation results showed that the fuzzy PID control method had a fast tracking performance and a strong robustness. Compared with those of traditional PID control, the feasibility and practicability of fuzzy PID control are verified in a robotic catheter minimally invasive operation.