A novel robust tuning approach based on model predictive control (MPC) for inductively coupled plasma (ICP) generation process is presented. Several key aspects related to this methodology are the modeling of the ICP generation process, robust joint tuning algorithm and semi-physical simulation of the MPC algorithm. The ICP generation process model is built by a system identification method based on steady and dynamic responses, followed by a general model predictive controller. Then, an automatic robust joint tuning (RJT) algorithm is developed for the MPC controller to quickly obtain the optimal weighting parameters. The proposed RJT algorithm can minimize the ICP generation control system's maximum total variations in the output with a specific dynamic performance requirement and model uncertainty, providing a trade-off between the dynamic performance and robustness. Finally, a semi-physical simulation system based on dSPACE and FPGA is designed to illustrate the effectiveness of the MPC controller for the ICP generation control process and the RJT algorithm. Experimental results indicate the validity and good performance of the proposed MPC controller and the RJT algorithm.

The surface of a hypersonic vehicle traveling at a speed exceeding Mach 10 is covered by a plasma sheath. The plasma sheath is a complex dynamic random medium that seriously attenuates electromagnetic (EM) waves and generates the so-called blackout phenomenon. However, owing to changes in vehicle flight parameters, such as the angle of attack, speed, and altitude, or the effects of plasma weakening control measures, the attenuation effect of the plasma sheath on EM waves weakens for a short time. At times, the amplitude of the EM waves is higher than the communication threshold, and the EM waves penetrate the plasma sheath in a so-called “communication window”. However, the random temporal variance of the plasma sheath parameters causes the required parameters of the “communication windows” to appear randomly, resulting in the traditional communication methods that needs to keep the communication link open for a long time being no longer applicable. To maximize the use of these “communication windows”, this paper proposes a short-frame fountain code (SFFC), constructs a time-varying plasma sheath channel model, and studies the relationship between the SFFC parameters and the transmission performance of this particular channel. Simulation and experimental results show that the use of SFFC improves the reliability of communication through the plasma sheath. The uninterrupted and correct transmission of information can be achieved even when the plasma equivalent frequency is close to the carrier frequency.