Robust PID control of propofol anaesthesia: Uncertainty limits performance, not PID structure

Background and Objective: New proposals to improve the regulation of hypnosis in anaesthesia based on development advanced control structures emerge continuously. However, a fair study analyse real benefits these compared simpler clinically validated PID-based solutions has not been presented so far. The main objective this work is performance limitations associated with using filtered PID controller, as high-order represented through Youla parameter. Methods: comparison consists two-steps methodology. First, two robust optimal controllers, considering effect inter-patient variability, are synthesised. A set 47 paediatric pharmacological models, identified from clinical data, used end. This model provides representative variability Second, individualised controllers synthesised for each set. For fairness comparison, same optimised all designs, robustness constraints considered. Controller synthesis performed utilising convex optimisation gradient-based methods relying algebraic differentiation. worst-case over patient comparison. Results: Two entire set, well individual-specific were optimised. All considered designs resulted similar frequency response characteristics. improvement was significant individually tuned controllers. difference between synthesized individual models significantly larger than different evaluated simulation. Although them showed acceptable results, provided slower responses. Conclusion: Taking technical considerations into account design only marginal differences when comparing an parameter its counterpart. much more detrimental imposed by simple structure controller.