How to find the gain when given a damping coefficient with rltool

I have a transfer function that I am putting into rltool. I need to find the gain that is needed in order for the damping coefficient to be 0.9. How can I find this with rltool?

s = tf('s');

zeta = 2/sqrt(13);

omega = sqrt(13);

Kq = -24;

T = 1.4;

H_thetadelta = minreal((Kq*(1+T*s))/(s*(s^2+2*zeta*omega*s+omega^2)))

rltool(-H_thetadelta)

Answer 1

[Balavignesh]

Hi Eden,

I understand that you want to use “rltool” to adjust the gain parameter to achieve a specific damping ratio. After you open the “rltool” window, if you drag and move the closed-loop poles (purple-coloured dots), you can observe that the damping ratio changes in the bottom-right corner of your screen. You may gradually increase or decrease the gain until the desired damping ratio is achieved. Once you have set the desired damping ratio, you can read its corresponding gain from the “Compensator Editor”window.