h. taei

In modern aircrafts, control allocation is one of the effective methods for executing specific maneuvers, time or energy reduction for determined operation, and compensating of actuators faults. For this purpose, the aircraft should be over-actuated in various channels. In this situation, control allocation means the distribution or division of the required control signals between aerodynamic surfaces (aerodynamic actuators) and the thrust vector control (TVC) system. Among the different approaches for control allocation, the use of methods based on soft computing is of interest. Therefore, the main goal of this article is utilization of fuzzy logic and multi-objective optimization to allocate control signals for the landing phase of the F/A-18 aircraft in the presence of elevator and TVC actuators. Therefore, flight modeling and simulation of aircraft has been done and by defining suitable fuzzy rules and specific objective functions, the ability of the developed allocation approach to converge the output variables to the expected values is demonstrated and finally, the aircraft completes the landing phase with desired accuracy and optimal control effort.

System Identification is used to derive the dynamic and mathematical model of a system using experimental data. If the case study system is an aircraft, this process is called aircraft system identification, which is used to estimate the stability and control derivatives of the aircraft. The least squares method is one of the methods used in the field of time and frequency to estimate the parameters of the aircraft. In this paper, system identification and estimation of F-16 aerodynamic coefficients are performed using the least squares method and the equation error approach. Hence the main focus is on the formulation of the aerodynamic model for estimating unknown coefficients using the least squares method. In this regard, nonlinear 6-DOF of the F-16 aircraft was simulated and using its results, system identification and estimation of transfer function, force coefficients and aerodynamic moments of the aircraft lateral-directional channel using regression of least squares and the results are analyzed. The results show that the modeling and estimation of the coefficients is compatible with the experimental data and can be suitable for further studies, including control objectives.