Control Engineering for BME
45 flashcards · Physics · by Kristóf Nagy
root locus steps
poles zeros find x axis parts, RHS odd poles --> zeros, symmetric around x-axis # asymptotes angle intersection/centroid break away/in
RL: # asymptotes
n_p - n_z
RL: intersection/centroid
σa=\sigma_a = σa= Σpi−Σzinp−nz\frac{\Sigma p_i - \Sigma z_i}{n_p - n_z}np−nzΣpi−Σzi
RL: asymptotes angle
θ=\theta = θ= ±(2k+1)πnp−nz\pm \frac{(2k+1)\pi}{n_p - n_z}±np−nz(2k+1)π k = 0, 1, 2, ... until enough for #asymp
RL: breakaway / break-in points
N'd - d'N = 0
RL: block diagram / transfer function
RL: real axis rule
number of all points (poles, zeros) must be ODD (páratlan) on the right-hand-side of any point of root-locus on the x-axis (real-axis)
bode: block diagram
H(s) = transfer function of the system
bode: standard form
bode magnitude
calculate this, and use the full as constant value in dB
bode magnitude
-20 dB/dec. at 1, it's 0
bode magnitude
+20 dB/dec. at 1, it's 0
bode magnitude
before p_i --> 0 after p_i --> -20dB/dec.
bode magnitude
before z_i --> 0 after z_i --> +20dB/dec.
(bode magnitude)
bode rules
split: multiply the types calculate each, plot (sketch them together) sum
bode phase
K>0: 0° (+) K<0: ±\pm± 180° (-)
bode phase
-90° constant
bode phase
+90° constant
bode phase
bode phase
ss TF
ss X(s) (or Y(s)?) output, Laplace transform solution method
making a ss
normal ma=... all forces in t space define x1=y, x2=y' write x1'=... (usually just x2) & x2'=... (this will the most part) put them into the matrix form make the other y1=... & y2=... to describe how is y in x (can also have a U part)
ss: P(s), eigenvalues
det(sI-A) (=0)
ss form
moving pick up point
after: 1/G before: G
moving sum junction
before: 1/G after: G
Nyquist sentence
gain margin
∠P(jωpc)=180°\angle P(j\omega_{pc})=180°∠P(jωpc)=180° gm=1∣G(jωpc)∣g_m = \frac{1}{|G(j\omega_{pc})|}gm=∣G(jωpc)∣1
phase margin
∣G(jωgc)∣=1|G(j\omega_{gc})|=1∣G(jωgc)∣=1 ϕm=180°+∠G(jωgc)\phi_m = 180° + \angle G(j\omega_{gc})ϕm=180°+∠G(jωgc)
2nd order system TF
1st order system TF
C(s)R(s)=as+a\frac{C(s)}{R(s)} = \frac{a}{s+a}R(s)C(s)=s+aa
R
L
C
(integral till t)
k (spring)
B or C or D (damper)
F=ma
F(s)=Ms2X(s)F(s)=Ms^2X(s)F(s)=Ms2X(s)
phase ϕ\phiϕ
add when (...)*(...) subtract if divided
magnitude M
multiply/divide normally when (...)*/(...)
steady state error analysis ess=e_{ss} = ess=
(for unity feedback)
names for input
RH criterion
no sign change in the 1st column no sign change in the coeffs # of sign changes = poles on the RHS (bad) side, rest on the good rows of zeros: poles on the jωj\omegajω axis (# is the line above s^n), take derivative and make that the next n+1 line, and continue can still be marginally stable if all other stuff matches
RH oscillation
s^1 = row of 0s = oscillation previous row: a*s^2+b=0 solution gives omega rad of resonance freq