Guidance command generation and nonlinear dynamic inversion control for reusable launch vehicles

Intelligent Adaptive Control Using LADP and IADP Applied to F-16 Aircraft with Imperfect Measurements

“…The time horizon (N) determines the number of previously measured data points used for the derivation of the OPFB policy evaluation and improvement equations. In order to assess the impact of this parameter on the performance, its value is changed in the range of [3,8] for the scenario described in Table 12. In Fig.…”

“…Again, the lowest time horizon possible (N=5) was found to be the best option for the PSO. However, when obtaining the RMSE performance for different time horizons in the range [3,8], it was observed that N=3 lead to the best performance even though the hyper-parameters were optimised for N=5, as it is shown in Fig. 53.…”

“…54 shows that the RMSE initially decreases to a minimum at N equals 6. This means that using N previous data points in the range [3,6] contributes to reducing the effect of the output noise on performance; whereas exploiting an N higher than 6 leads to a higher initial deviation that counteracts the benefits of the reduced output noise effects. This effect is most notable when there is no initial deviation in the angle of attack.…”

“…At the moment, most flight control systems exploit gain scheduling [1], method which allows adaptation to different flight regimes but that can not cope with unexpected scenarios. Therefore, other nonlinear control approaches have been studied, such as Nonlinear Dynamic Inversion (NDI) [2,3] and Backstepping (BS) [1]. The main idea behind NDI is to perform a state local coordinate transformation in order to cancel the nonlinear terms and linearize the dynamics of the aircraft.…”

On modeling and dynamics of a multiple launch rocket system

“…Generally, the MLRS dynamics modeling and analysis methods include the Newton-Euler method, 7 Lagrange method, 8,9 Kane method, 10,11 Huston method, 12 and methods using software such as Ansys, 13,14 Abaqus, 15 Adams, 16,17 RecurDyn, 14 and Modelica. [18][19][20] As a sophisticated multibody system, the difficulty of studying MLRS dynamics lies in the interactions and couplings of the launcher, the carrier, and the rocket. The dynamic analysis of the MLRS developed slowly before the advent of modern analog and digital computers.…”