tune an autopilot in matlab

One popular method for tuning an autopilot control system is the PID tuning method. This involves adjusting the Proportional, Integral, and Derivative gains until the system responds appropriately to disturbances.

Here's an example code that tunes a PID controller for a given plant model in MATLAB:

main.m
% Plant Model
num = [1];
den = [1 5 12];
G = tf(num, den);

% PID Controller
Kp = 1;
Ki = 0.5;
Kd = 0.1;
C = pid(Kp, Ki, Kd);

% Feedback loop
T = feedback(C*G, 1);

% Step response
step(T);

% Step response with overshoot and settling time specifications
stepinfo(T)

% Root Locus plot
rlocus(T)

% Stability margins
[Gm, Pm, Wg, Wp] = margin(T)

% Nyquist plot
nyquist(T)
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In the above code, we have defined our plant model (G) as a transfer function with numerator and denominator coefficients. We have also set initial values for the PID gains (Kp, Ki, and Kd).

We then create a feedback loop with our controller (C) and plant model (G) using the feedback function. We can use the step command to visualize the step response of our closed-loop system.

We can then use the stepinfo command to check that our response meets certain design specifications, such as overshoot and settling time.

We can also use other MATLAB functions such as rlocus to plot the root locus of our system, margin to calculate stability margins, and nyquist to visualize the Nyquist stability criterion.

The values of the PID gains can then be adjusted until the desired system response is achieved.