Fuzzy Logic Control of Toroidal Plasmas

本研究旨在将模糊逻辑应用于等离子体控制，阐明该算法的适用性，探索未来聚变反应堆控制的前景。磁约束环形等离子体的控制对象有等离子体电流、等离子体位置、等离子体截面、等离子体密度、加热功率等。除此之外，在反应堆中还需要控制中子产生速率和聚变功率输出。到目前为止，在融合研究中采用的是经典的PID（比例、积分和导数）控制方案。随着机器系统规模的扩大，需要一种灵活可靠的新型控制理念。作者正在继续进行托卡马克和螺旋系统的等离子体控制研究，并开发等离子体建模的计算机代码。在模糊控制研究方面，将三角隶属函数的最小-最大重心模糊化方法应用于螺旋等离子体中的等离子体电流控制。在本会计年度（平成第6年度），在LHD等离子体控制研发机中添加了模糊控制算法。该控制方案将应用于核聚变实验机和核聚变动力堆，有助于实现核聚变控制的系统化。在研究之初，仅对模糊控制逻辑进行了研究，但最近开始对各种智能控制进行了广泛而基础的研究，包括与模糊逻辑相结合的神经网络和新概念（混沌工程和通用算法）。

This research aims at applying fuzzy logic to the plasma control, at clarifying the applicability of this algorism, and at searching for the prospect of the future fusion reactor control.The control objets in magnetically confined toroidal plasmas are plasma current, plasma position, plasma cross-section, plasma density, heating power and so on. In addition to those, in the reactor, neutron production rate and fusion power output should be controlled. Until now classical PID (Proportional, Integrated and Derivative) control schemes are adopted in the fusion research. Since the machine system becomes bigger, a new flexible and reliable control concept is being required.The author are continuing the plasma control research in both tokamak and helical systems, and developing computer codes for plasma modeling. As for fuzzy control research, a mini-max center-of-gravity fuzzification method with triangular membership function is applied to the plasma current control in helical plasma.During this fiscal year (Heisei 6th) a fuzzy control algorism was added to the LHD plasma control R&D machine. This control scheme will be applied to the fusion experimental machine and fusion power reactor, and will contribute to the systematization of fusion control. At the beginning of this research, only fuzzy control logic was surveyed, but wide and basic investigations on various intelligent controls have recently been started, including neural network combined with fuzzy logic and new concepts (Chaos Engineering and Generic Algorism).