Application Of Self-tuning Fuzzy Control Algorithm In The Temperature Control System For Tumor Intervention Hyperthermia

Tumor intervention hyperthermia system using selective or superselective arterial catheterization, balloon catheter to block the blood vessels supporting the tumor, to block the tumor blood supply resulting in ischemia purpose, high precision the temperature of liquid injected into the tumor lesions chemotherapy, the nutrient vessels of the tumor rupture , thereby undermining the nutrient vessels of the tumor bed, hydrothermal leak into tumor tissue, the realization of inter-organizational heating, the tumor tissue coagulation necrosis. That hyperthermia biology today: the death of tumor cells, the critical temperature is 42.5-43℃, hig-temperature hyperthermia temperature≥43℃.Longer high-temperature hyperthermia to the tumor tissue, can effectively eliminate tumor cells, while hyperthermia can increase the maximum cytotoxicity of chemotherapeutic agents. The study showed that: When the treatment temperature exceeds 42.5℃, the temperature for each additional 1℃, destruction of tumor cells increased twice, the treatment time can be shortened 1 / 2. Therefore, intervention to solve the exact temperature and temperature hyperthermia technology is very important, so as to not only kill tumor cells but also normal cells can maintain the temperature at a safe temperature range.In this paper, based on the analysis of the basic principle of the tumor intervention hyperthermia system, studied the characteristics of the temperature control system in-depth. (1) According to the heated liquid bath temperature feature, combined with the basic heat transfer theory, designed thermal resistance and catheter temperature measurement experiments, derived liquid outlet temperature and the water temperature formula. (2) In order to ensure the speed and temperature control accuracy of steady-state control, the control algorithm using sub-control strategy, the coarse and fine adjustment control. Coarse control with full power heating means, so as soon as possible to the predict temperature of water bath temperature, liquid temperature is fast approaching when the set temperature value, lower heating power and switch to fine tune control. (3) To achieve accurate and effective temperature control for fine-tuning control does not rely on an accurate model of computing with temperature difference on the adaptive fuzzy PID control algorithm. It will control the adaptive ability of artificial intelligence and conventional PID control algorithm is inherently robust, simple, easy to realize the advantages of combining both fuzzy control to overcome the shortcomings of accuracy is not high, but also played a steady-state accuracy PID control high benefits.Experiments show that the control algorithm to overcome the tumor intervention of hyperthermia temperature control system of nonlinear, large delay, within the liquid flow rate and pipe material properties change, an effective solution to the system temperature control in case of changing the injection flow rate and the target treatment temperature, to avoid large temperature overshoot. It has the characteristics of strong ability to adapt, good dynamic performance, high steady precision.