Aero1.m Analyses the longitudinal dynamics of a pransport aircraft, trimmed at V_0 = 250 ft/s, and flying at a low altitude. In the model, all angles and angular rates are in radians, airspeed is in ft/s, throttle is in lbs, and elevator deflections are in radians. Analysied the the open loop eigenvalues for both coupled and short period dynamics. Simulated the open-loop system response due to elevator and thrust step inputs.
When the elevator is deflected trailing edge up to pitch the vehicle nose up, there is a small instant decrease in the vertical acceleration. Then, Az starts to increase, resulting in the aircraft pitch-up motion. This transient is caused by the elevator deflecting upward and creating a small negative lift increment. As a result, the vertical acceleration momentarily goes into the “wrong” direction before it reverses and builds up. These dynamics can also be explained by the fact that there is a nonminimum phase zero (with a positive real part) in the transfer function from de to Az . It is important to understand that all tail-driven aerial vehicles have similar characteristics. This phenomenon becomes very important during control design.
Aero1_4.m
Considering the lateral-directional dyanmics of a passanger aircraft, in a cruise configuration where the roll and sideslip angles are in radians, the angular rates are in rad/s, and the aileron and rudder deflections are in radians.
Observed the roll rate response due to aileron and the coupling between the roll and yaw rates (called the “Dutch roll” mode). These dynamics are fast when compared to the much slower changes in the roll angle (called the “roll subsidence” mode). Similar to short period, the roll rate and the Dutch roll modes are the main quantities for stabilization and regulation. This task is often accomplished during the so-called inner-loop control design phase, where the angular rates are stabilized via feedback connections, driving the aileron and the rudder. For the inner-loop design, the bank dynamics are ignored, and the three-dimensional lateral–directional model is utilized.
Extracted these dynamics form the model data and simulated responses of the simplified model due to the same step inputs in aileron and rudder.