چكيده به لاتين
This thesis intends to stabilize the flight of an avian-scale flapping robot with articulated wings, leading to control of the flight altitude. First of all, modeling has performed using multibody dynamics, considering a couple of inner and outer wings, a fuselage, and a tail.
The equations of motion have derived from Lagrange equations. Kampf mechanism, inspired by the birds, used to drive the inner and outer wings with a phase shift. The aerodynamic model obtained from applying the blade element theory to the wings divided into twelve elements, considering the inner and outer wing distinction. The aerodynamic forces emerging from the movement of wing elements, in terms of flapping frequency and flight speed, are determined separately. Regarding the flight path angle and effective angle of attack, aerodynamic forces of the entire wings have achieved in horizontal and vertical axes. The coupling of aerodynamic and dynamic completes the nonlinear time-periodic equations (NLTP). Flight stabilization is possible through the tail of the robot. Due to the impact of the fuselage pitch angle on flight altitude, cascade control used to control fuselage and tail pitch angles in inner loops and altitude in the outer one. PID controller was used to regulating the performance of the loops, the coefficients of which have been designed optimally.
Since the periodicity in the solution originated isolated orbits, there exist limit cycles in trim states of the system. The stability of this system is through the Floquet theorem, in which the time-shooting method used to obtain limit cycle trajectories. With this method, an integrated matrix called the monodromy matrix obtained, which by analyzing its eigenvalues, the instability of the open-loop system concluded. To deal with uncertainties coming from severe nonlinear nature, subsystem interaction, and sensitivity to weather conditions, a robust adaptive controller with a sliding mode adapting mechanism designed to ensure the overall system boundedness as well as subsystems. This controller is the outcome of a cooperation between observer and sliding mode control. A comparison of the results shows the excellent performance of the adaptive controller, which will be very efficient for designing high-level controllers.
