Systematic design of a multi-input multi-output controller by model-based decoupling: a demonstration on TCV using multi-species gas injection

Abstract In this paper, we present the first results of a systematically designed multi-input multi-output gas-injection controller on TCV.
We demonstrate simultaneous real-time control NII emission front position and line-integrated electron density using nitrogen deuterium gas injection.
Injection and/or affects both density. 
This interplay between loops is termed interaction and, when strongly present, makes designing significantly more complex problem.
Interaction can be reduced to an acceptable level by redefining inputs, decoupling problem separated single-input single-output problems.
We how achieve defining virtual inputs from linear combinations actuators available.
For demonstration TCV, injection are computed transfer-function models obtain these inputs.
The reduce in control-relevant frequency range point where considered decoupled, allowing for much simpler design controllers each loop.
Implementing with gives controller.
This approach well established community, presented here as drive developments strategies.
In particular, envisioned particle- heat fluxes impacting divertor targets multiple species.