On dynamic input allocation for set-point regulation of the JET tokamak plasma shape

In this paper we propose a solution to the input saturation avoidance problem in the JET tokamak shape control by illustrating its capabilities to enforce coil currents selections that tend to move away from the saturation limits within the allowable degrees of freedom. The proposed solution revisits the dynamic allocation scheme first proposed in [10] for input redundant plants and generalized in [6] and [9] for not input redundant ones. In particular we propose a different scheme for the input allocation, more suitable within a set-point regulation setting, and prove its convergence properties. We also present simulation results to assess the steady-state and transient performances obtained with the novel scheme, as compared to the previous approaches.