q1 what will

stable approaches zero as time approaches infinty

unstable grows without bound as time approaches infinty

critically (marginally) stable neither decays nor grows but remains constant

system is stable if erery bounded input yields a bound output. The bounded input, bound output (BIBO) stability

system is unstable if any bounded input yields a unbounded output

syms s t
f_t = 5*exp(-2*t)

f_t = 

f=laplace(f_t,s)

f = 

syms s t
y=(s+3)/(s*(s+1))

y = 

f=ilaplace(y,t)

f = 

figure
ezplot(f,[0 15])

G = tf([1.5],[1 1 0.5])

G =
 
       1.5
  -------------
  s^2 + s + 0.5
 
Continuous-time transfer function.

figure
step(G) 
grid;

stepinfo(G)

ans = struct with fields:
         RiseTime: 3.0390
    TransientTime: 8.4326
     SettlingTime: 8.4326
      SettlingMin: 2.7103
      SettlingMax: 3.1296
        Overshoot: 4.3210
       Undershoot: 0
             Peak: 3.1296
         PeakTime: 6.2630

h = feedback(G,1)

h =
 
      1.5
  -----------
  s^2 + s + 2
 
Continuous-time transfer function.

figure
step(h)              % step
grid;

stepinfo(h) 

ans = struct with fields:
         RiseTime: 0.9887
    TransientTime: 7.7420
     SettlingTime: 7.7420
      SettlingMin: 0.6803
      SettlingMax: 0.9787
        Overshoot: 30.4890
       Undershoot: 0
             Peak: 0.9787
         PeakTime: 2.3947

H = tf([1],[1 4 12])

H =
 
        1
  --------------
  s^2 + 4 s + 12
 
Continuous-time transfer function.

z=zero(H)

z =

  0×1 empty double column vector

p=pole(H)

p = 
  -2.0000 + 2.8284i
  -2.0000 - 2.8284i

figure
pzmap(H)        % zero and pole

figure
step(H)

stepinfo(H)

ans = struct with fields:
         RiseTime: 0.5201
    TransientTime: 1.7021
     SettlingTime: 1.7021
      SettlingMin: 0.0755
      SettlingMax: 0.0924
        Overshoot: 10.8433
       Undershoot: 0
             Peak: 0.0924
         PeakTime: 1.1052

G1 =tf([1 2],[1]);
G2 =tf([1],[1 1]);
S =series(G1,G2)     % block diagram

S =
 
  s + 2
  -----
  s + 1
 
Continuous-time transfer function.

G3 =tf([2],[1 3]);
T_final =feedback(S,G3)

T_final =
 
  s^2 + 5 s + 6
  -------------
  s^2 + 6 s + 7
 
Continuous-time transfer function.

G = tf([4],[1 7 6])

G =
 
        4
  -------------
  s^2 + 7 s + 6
 
Continuous-time transfer function.

figure
step(G)

Kp = 50;
G_closed = feedback(G*Kp,1)

G_closed =
 
        200
  ---------------
  s^2 + 7 s + 206
 
Continuous-time transfer function.

figure
step(G_closed)                % Unity feedback open loop 

Kd=5;
G_comp = tf([Kd Kp],[1])

G_comp =
 
  5 s + 50
 
Continuous-time transfer function.

G_closed = feedback(G_comp*G, 1)

G_closed =
 
     20 s + 200
  ----------------
  s^2 + 27 s + 206
 
Continuous-time transfer function.

figure
step(G_closed)

G = tf([5],[0.5 1 0])

G =
 
       5
  -----------
  0.5 s^2 + s
 
Continuous-time transfer function.

figure
bode(G)
grid;

figure
margin(G)                                          

% Bode Plot
K = 0.4416

K = 0.4416

C= tf([K*5],[0.5 1 0])

C =
 
     2.208
  -----------
  0.5 s^2 + s
 
Continuous-time transfer function.

figure
bode(C)
grid;

figure
margin(C)

The system is stable in closed loop because when the gain is crossing Zero, the phase is still above -180 degree. This makes the closed loop stable

1. Operator Interface (HMI): The operator uses a Human-Machine Interface (HMI) to interact with the SCADA system (Example PC with Video Display Unit (VDU) and Keyboard: Inputs commands/messages).
2. MTU (Master Terminal Unit): This is the central part of the SCADA system, located at the central monitoring station. It communicates with the RTUs, gathers data, processes it, and displays it to the operator. It also sends control commands to the RTUs Normally, the M T U will have auxiliary devices (e.g., printers and backup memories) attached to it.
3. RTUs (Remote Terminal Units): These are field devices located at remote sites (RTU #1, RTU #2, RTU #3, RTU #4) that interface with sensors and actuators. They collect data from the sensors and transmit it to the SCADA master station. They also receive commands from the SCADA system to control field devices.
4. Modems: These devices are used to convert digital signals from the RTUs to analog signals for transmission over long distances. They facilitate communication between the RTUs and the MTU via various communication channels.
5. Communication Network / Infrastructure:Wired Communication: The figure shows wired connections between some RTUs and the MTU through modems, indicating the use of physical communication lines such as telephone lines or dedicated network cables. Radio Communication: Some RTUs communicate with the MTU via radio links. This setup involves modems and radio transmitters/receivers, allowing for wireless communication, which is useful in remote or difficult-to-access locations.

[Rik]

Your question was hardly formatted at all, and it isn't clear what your actual question is. Your code doesn't really result in any actual error messages.

Have a read here and here. It will greatly improve your chances of getting an answer.

[John D'Errico]

@Hamad

There is no question at all in this. Only a single error message where it appears you have inadvertantly made a comment as executable code, and then allowed MATLAB to try to execute the comment.

Bode Plot

Unrecognized function or variable 'Bode'.

So, if you have a question, then ask it. Otherwise this post does not belong on Answers as it is.

Answer 1

[dpb]

Bode Plot

Unrecognized function or variable 'Bode'.

The function is

which -all bodeplot

/MATLAB/toolbox/shared/controllib/engine/@DynamicSystem/bodeplot.m % DynamicSystem method