  This paper presents a model-based control architecture. Based on the Medical
Cyber-physical Systems (MCPS) concept, we construct a safe and reliable
automatic anesthesia control closed-loop system. The control architecture uses
the patient's propofol pharmacokinetic/pharmacodynamic model, using the
calculated results as a feedback signal to correct the model's uncertainties.
During anesthesia, the bispectral index (BIS) level is used as a control
variable to control the depth of anesthesia. The proposed control architecture
can automatically adjust the infusion rate of anesthesia drugs without
concussion or overshoot. The system adaptively adjusts the drug infusion rate
to maintain the BIS level at a stable target value. We utilized MATLAB-Simulink
to verify the effectiveness of this method, and the robustness test was carried
out by adding noise blocks. At last, we analyze the simulation result of the
average patient. In general, the proposed method achieves a stable and fast
induction period during the maintenance phase of anesthesia with a good
disturbance rejection.
