Analysis and design of multirate output feedback controller for hyperthermia system

Abstract

Cancer is a major threat to human life . Researchers are looking for improved cancer treatments over the existing methods of surgery, radiotherapy and chemotherapy. Hyperthermia the heating of cancerous tumours, can improve complete response rates when added as an adjuvant treatment to radiation therapy. This research features the modelling and design of multirate output feedback controller via reduced order model for a scanned focused ultrasound hyperthermia system. The multi rate output feedback controllers such as Periodic Output Feedback (POF) and Fast Output Sampling (FOS) feedback controllers are designed. The performance of the controller is evaluated by framing a desired trajectory which meets the goals of hyperthermia feedback control system. To compensate for the lack of robustness in the face of uncertainty in blood perfusion of the designed controllers a Discrete Sliding Mode Controller using Fast Output Sampling (DSMCFOS) is designed. By proper choice of tuning parameters in the reaching law, the dynamic response of the closed-loop system is improved. Simulations proved that designed Discrete Sliding Mode Controller using FOS efficiently adapts to uncertainties and model mismatch during the course of treatment. Through the results of applications, the proposed discrete sliding mode control scheme using fast output sampling is shown to be very effective and useful. newline