Marco Ariola

Plasma shape control for the JET tokamak: an optimal output regulation approach

The eXtreme Shape Controller, designed and implemented on the JET tokamak, was described. The controller regulates the plasma shape as specified in terms of plasma-wall distances and maintains this plasma shape in the presence of significant variations of critical plasma parameters, namely the poloidal beta, the internal inductance, and the plasma current. The design procedure is based on the SVD of the plant output matrix. This procedure accounts for specifications on the accuracy of the controller variables as well as the maximum allowable control effort. The new controller has been fully commissioned on the JET tokamak, is in regular operation, and is delivering the expected performance.

Model predictive control for a multi-body slung-load system

Abstract In this paper we present a multi-level and distributed control system, based on a robust Model Predictive Control (MPC) technique, for a multi-body slung-load system. In particular, we consider a swarm of autonomous multi-copters which are connected by wires to a suspended payload. The payload reference trajectory is obtained through a constrained optimization, then the reference trajectory for each UAV is derived on the basis of the known shape of the formation, while taking into account operational constraints such as collision avoidance and cruise speed. Trajectory tracking is performed by a multi-level flight control system based on a MPC technique and a PID control system. Numerical simulations have been performed in order to test the control system in realistic scenarios. In particular, the multi-copters are modeled by the six Degrees-of-Freedom (6DOF) model, the constraint forces on the wires are calculated using the Udwadia–Kalaba equation and the external disturbances (atmospheric turbulence and gust) are included in the simulation. Simulation results are encouraging, thus making the proposed system an appealing candidate for similar applications.

Plasma Modelling for Magnetic Control

The aim of this chapter is to derive a linearized mathematical model describing the interaction between the plasma ring and the voltages applied to the poloidal field coils.

An SFDI observer-based scheme for a general aviation aircraft

Abstract The problem of detecting and isolating sensor faults (sensor fault detection and isolation-SFDI) on a general aviation aircraft, in the presence of external disturbances, is considered. The proposed approach consists of an extended Kalman observer applied to an augmented aircraft plant, where some integrators are added to the output variables subject to faults. The output of the integrators should be ideally zero in the absence of model uncertainties, external disturbances and sensor faults. A threshold-based decision making system is adopted where the residuals are weighted with gains coming from the solution to an optimization problem. The proposed nonlinear observer was tested both numerically on a large database of simulations in the presence of disturbances and model uncertainties and on input-output data recorded during real flights. In this case, the possibility of successfully applying the proposed technique to detect and isolate faults on inertial and air data sensors, modelled as step or ramp signals artificially added to the real measurements, is shown.

Development of an autonomous multi-rotor UAV for outdoor missions in unknown environments

In this paper we present the development of a multi-rotor system for autonomous outdoor flights in an unknown environment. We propose a modular framework scheme to perform the functions of guidance, navigation and control using the sensor measurements. The localization and mapping tasks are performed simultaneously by the guidance module through an Extended Kalman Filter (EKF). The estimated map allows the guidance module to plan the reference trajectory avoiding the collision by evaluating the solutions of a sequence of constrained optimization problems. The control module computes the autopilot commands to follow the reference trajectory through a robust Model Predictive Control technique. The overall system is tested through simulations of realist scenarios.

Plasma Shape Control at JET

The controller design described in this chapter has been carried out in the framework of some projects aimed at assessing the possibility of controlling accurately highly elongated plasmas at JET with the existing active circuits and control hardware [95].

Plasma Shape Control for ITER

In this chapter, we show that the configuration of the ITER tokamak enables the design of a low-order controller based on the fact that the vertical position control and the plasma current and shape control can be performed on different time scales.

Plasma Position and Current Control at FTU

In this chapter we present the design of a plasma radial position and current controller for the FTU tokamak. This design is based on a detailed simulation model of the tokamak; exploiting this model-based approach, no experimental tuning of the controller gains has been necessary.

Plasma Magnetic Control Problem

In the previous chapters, we have shown how it is possible to derive an FDLTI (finite-dimension linear time-invariant) model able to describe the interactions between the plasma and the surrounding structures, in terms of specified inputs and outputs, under certain simplifying assumptions.

Modelling of the Resistive Wall Modes

In Sect. 2.4 we have introduced the concept of plasma equilibrium where the magnetic confinement forces produced by the active coils of the tokamak balance the plasma pressure.