Simulink Simulation of Fighter Aircraft Longitudinal Motion: Pitch Rate Analysis

The purpose is to use Simulink to simulate a (much simplified) model of the longitudinal motion of a fighter aircraft. The 'angle of attack' is the angle between the direction a plane is pointing, and the direction in which it actually moves through the air. For a plane flying at approximately constant altitude, this is equivalent to the 'pitch angle', as illustrated in Fig. 3. This angle is important because it produces a lift force perpendicular to the axis of the plane, and hence a 'normal acceleration', (also shown in the figure).

The pilot wants to be able to control the pitch angle, and does so ultimately by rotating the front fins, and tail elevators of the aircraft, shown in Fig. 4. The first task is therefore to model the effect of these movements on the 'pitch rate', where...

b. Pitch Rate, q The rate at which the pitch angle changes, (the 'pitch rate', q), is determined mainly by the angle of the front fins of the aircraft shown in Fig. 4. Indeed aerodynamic modeling shows that this relationship can be described by the differential equation: Q(s)/d(s)=(7.25s+11.27)/(s^2+3.1s-8.82)
其中，gain 是指 gears，数值是-5

Sketch of pitch rate response to a step change in the control input here Comment on the response Without a specific step change input value, it is difficult to provide a detailed comment on the pitch rate response. However, in general, the response can be analyzed by looking at the key characteristics such as rise time, settling time, overshoot, and steady-state error. The response can also be classified as underdamped, overdamped, or critically damped based on the number and location of poles and zeros in the transfer function. The gain of -5 indicates that the output (pitch rate) will be negatively proportional to the input (control movement).