create a pid in matlab

To create a PID controller in Matlab, you can use the pid function, which takes three parameters as inputs: the proportional gain (Kp), the integral gain (Ki), and the derivative gain (Kd). Here's an example code snippet that creates a PID controller with gains of Kp = 1, Ki = 0.5, and Kd = 0.2:

main.m
Kp = 1;
Ki = 0.5;
Kd = 0.2;

pid_controller = pid(Kp, Ki, Kd);
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Once you have created the PID controller, you can use it to control a system by passing the controller object into the feedback function. For example, let's say you have a plant transfer function G(s) and you want to control it with the PID controller. You can use the feedback function to create a closed-loop transfer function, as shown below:

main.m
G = tf([1], [1 2 3]);  % Plant transfer function
sys_cl = feedback(pid_controller * G, 1);
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In this code, the * operator is used to multiply the PID controller by the plant transfer function G. The resulting transfer function is fed back to the controller using the feedback function with a unity (1) negative feedback loop.

Finally, you can analyze the closed-loop system by plotting its step response using the step function:

main.m
step(sys_cl);
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This will generate a step response plot for the closed-loop system.