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Paul


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155 total contributions since 2011

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Answered
solving integral equation where the unknow is the upper limit
Assuming T and T0 are positive, it looks like there are two values of T that will satisfy the equation. Not sure why your code i...

2 days ago | 0

Answered
Help using symbolic transfer function
Can do it by hand, at least for this simple case: >> syms K1 K2 K real >> syms s >> K = sym(6); >> G(s) = K1*K2/(s^2 - 3*s -...

2 days ago | 0

Answered
Extract values from Nyquist for negative frequencies
The Nyquist plot is symmetric, so the compex cojugate of the output would correspond to the negative frequencies. [re_pos,im_po...

3 days ago | 0

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Answered
Reducing fast dynamic poles in a transfer function.
Maybe freqsep() is what you want: >> G=tf(1,conv([1 5],[1 70])) G = 1 ---------------- s^2 + 75 s + 350 ...

4 days ago | 0

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Answered
Matlab Nyquist Sampling Problem
According to doc nyquist you can do nyquist(k1,w) where w is a frequency vector of your choosing.

6 days ago | 0

Answered
The output of my executed code is not giving the answer I am looking for when using the symUnit function
There are many options to which H*Hz can be converted; which one should be chosen automatically? But you can try it yourself: ...

10 days ago | 2

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Answered
Spring mass damper system shows position of mass only to be on positive side
The transfer function from Force to Position has dc gain of 2. The input F has a value of 2, so the steady state of the output ...

11 days ago | 1

Answered
Integral of exp(-x)*P(x)/Q(x) in terms of exponential integral in symbolic tooblox
What is the concern with the result that was returned? It looks like the SMT came back with the best answer it could with the in...

17 days ago | 0

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Answered
Zero-crossings of Nyquist Diagram
By definition, the gain margin is defined at the point(s) where the Nyquist plot crosses the real axis. Use the allmargin() func...

19 days ago | 0

Answered
What is wrong with my differentiation of function of phi(t)?
I think what you want is to substitute a variable for diff(fi,t), differenitate wrt to that variable, and substitute back. >> s...

20 days ago | 1

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Answered
Reduce block diagrams symbolically
Assuming you want final result in terms of the gi(s): syms g1(s) g2(s) g3(s) g4(s) g5(s) symsys1 = g4(s)-g5(s); symsys2 = g...

25 days ago | 0

Answered
Implement a Transfer Function in Code state space higher order
The short story is that dt is too large for this system. Try running with: dt = 1e-5; t = 0:dt:0.03; And don't set u(1) = 0....

25 days ago | 0

Answered
Symbolic Math shows weird behavior - not seen in Wolfram or Octave
It looks like the expected solution can be obtained with some work. Maybe someone else can get there faster. >> syms x real >...

25 days ago | 1

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Answered
Sample Time and simOut Interaction
Keep the orginal solver settings you had (assuming they gave you an acceptable solution). Set the Sample Time parameter in the ...

28 days ago | 1

Answered
Problem in matrix partition for uncertain system: how to find matrices A, B1, B2, C1, C2, D11, D12, D21, D22?
Suppose you have a model xdot = A*x + B1*w + B2*u z = C1*x + D11*w + D12*u y = C2*x + D21*w + D22*u This system can be rewri...

29 days ago | 0

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Answered
SS2TF Error
If you want the numerical answer, then don't even bother with the symbolic stuff. Just assign values to the variables R1, R2, C...

29 days ago | 0

Question


Can a Comma Separated List be Generated Directly from a sym Array?
Can a comma separated list be generated directly from a sym array for use as input to a sym function? >> xvar=sym('x',[1 4]) ...

1 month ago | 1 answer | 0

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Answered
How to multiply transfer function in matrix form?
The result you seek can be found by (after running the code in the original question): >> minreal(Dc) ans = -40.36...

1 month ago | 0

Answered
Gaussian Mixture Model using gmdistribution
Try this: >> mu=[6.25;4.33]; >> sigma=reshape([0.52 0.37],1,1,2); % third dimesion required, note that sigma are VARIANCES pe...

1 month ago | 1

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Answered
Transfer Function and step response
You need the the Control System Toolbox.

1 month ago | 0

Answered
conversion between state space and transfer function
An infinite number of state space realizations correspond to a single transfer function. From a transfer function, the Control S...

1 month ago | 1

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Answered
Feedback command for MIMO systems in MATLAB
I think this does what you want (assuming negative feedback) Pitch_State = STATE_SPACE_MODEL({'x';'Theta'},'Pitch Torque') PIT...

1 month ago | 0

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Answered
Can I define the initial condition at a nonzero point using Simulink integator?
Look at using the Start Time parameter on the Solver Pane (link). As best I can tell, it will do exactly what you want; initial...

1 month ago | 0

Answered
Fast Fourier Transform Zero Padding
Try changing these lines: L = length(O2_exp); Y = fft(O2_exp); to L = nfft; % select nfft > numel(O2_e...

1 month ago | 0

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Answered
Simulink control with moving average
A difference equation of the form y(k)=(c0*u(k)+c1*u(k-1)+c2*u(k-2)+c3*u(k-4)+c4*u(k-4))/D can be implemeted with one of the b...

1 month ago | 0

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Answered
State Space with Disturbance
Combine d and u into a single input vector: Xdot = A*X + [B F] * [u;d] y = C*X + [D 0]*[u:d] % assuming the disurbance doesn'...

1 month ago | 0

Question


Why Would fplot(f) and fplot(vpa(f)) Show Different Results?
I'm seeing different results between fplot for a symfun object, the fplot of the vpa form of that object, and the regular old pl...

1 month ago | 1 answer | 0

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Answered
How do you do Unity Feedback on Matlab? (Transfer Functions)
Check the doc page for feedback() doc feedback In this case, the feedback line isn't "empty," it has a gain of 1 (or if you pr...

2 months ago | 0

Answered
Illustration of Frequency Response (magnitude and phase response)
if you wnat to plot them yourself, then use plot(), or semilogx() or whatever plotting function meets your needs. Or you can de...

2 months ago | 0

Question


Peculiar Result with Solve (Symbolic Math Toolbox) with Three Equations and Three Unknowns. Can Anyone Explain?
Suppose I have three equations and three unknowns as so: >> syms X1 X2 X3 real >> e1 = X1/(X1 + X2 + X3) == 0.1; >> e2 = X2/(...

2 months ago | 1 answer | 0

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