Department of Mathematics and Statistics, Curtin University, Australia.
Department of Electrical Energy, Metals, Mechanical Constructions and Systems, Ghent University, Belgium.
Comput Methods Programs Biomed. 2017 Jun;144:21-35. doi: 10.1016/j.cmpb.2017.03.013. Epub 2017 Mar 18.
This paper addresses the use of proportional-integral-derivative controllers for regulating the depth of hypnosis in anesthesia by using propofol administration and the bispectral index as a controlled variable. In fact, introducing an automatic control system might provide significant benefits for the patient in reducing the risk for under- and over-dosing.
In this study, the controller parameters are obtained through genetic algorithms by solving a min-max optimization problem. A set of 12 patient models representative of a large population variance is used to test controller robustness. The worst-case performance in the considered population is minimized considering two different scenarios: the induction case and the maintenance case.
Our results indicate that including a gain scheduling strategy enables optimal performance for induction and maintenance phases, separately. Using a single tuning to address both tasks may results in a loss of performance up to 102% in the induction phase and up to 31% in the maintenance phase. Further on, it is shown that a suitably designed low-pass filter on the controller output can handle the trade-off between the performance and the noise effect in the control variable.
Optimally tuned PID controllers provide a fast induction time with an acceptable overshoot and a satisfactory disturbance rejection performance during maintenance. These features make them a very good tool for comparison when other control algorithms are developed.
本文探讨了使用比例-积分-微分控制器通过丙泊酚给药和双谱指数作为控制变量来调节麻醉深度。事实上，引入自动控制系统可能会为患者带来显著的益处，降低用药不足和过量的风险。
在这项研究中，通过求解最小-最大优化问题，使用遗传算法获得控制器参数。使用一组代表较大人群变异性的 12 个患者模型来测试控制器的鲁棒性。考虑两种不同情况：诱导阶段和维持阶段，将考虑范围内最差性能最小化。
我们的结果表明，包含增益调度策略可分别实现诱导和维持阶段的最佳性能。使用单一调谐来解决这两个任务可能会导致诱导阶段性能损失高达 102%，维持阶段性能损失高达 31%。此外，还表明控制器输出上的适当设计的低通滤波器可以在控制变量的性能和噪声影响之间进行权衡。
优化后的 PID 控制器在维持阶段提供了快速的诱导时间，具有可接受的过冲和令人满意的抗扰性能。这些特性使它们成为开发其他控制算法时进行比较的非常好的工具。
