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The plasma vertical position system in a tokamak device can be open-loop unstable with time-varying dynamics, such that the instability increases with system dynamical changes. Time-varying unstable dynamics makes the plasma vertical position a particularly difficult one to control with traditional fixed-coefficient controllers. A self-tuning technique offers a new solution of the plasma vertical position control problem by an adaptive control approach. Specifically, the self-tuning controller automatically tunes the controller parameters without an a priori knowledge of the system dynamics and continuously tracks dynamical changes within the system, thereby providing the system with auto-tuning and adaptive tuning capabilities. An overview of the self-tuning methods is given, and their applicability to a simulation of the Joint European Torus (JET) vertical plasma positions system is illustrated. Specifically, the applicability of pole-assignment and generalized predictive control self-tuning methods to the vertical plasma position system is demonstrated. 26 refs., 16 figs., 1 tab.

This paper reports on the Next European Torus fusion device which is a fully engineered prototype for a demonstration power source. The semicontinuous nature of some modes of operation necessitates both data processing and acquisition to be in real time. The high reliability and availability needed demands a fault-tolerant system. Additionally, there must be a flexible approach to allow for its experimental aspects. These criteria are detailed and embodied in a prototype design for the control system architecture.