Converting a simple mass-spring system to state-space model, how?

AI Thread Summary
The discussion focuses on converting a simple mass-spring system represented by the equation m*x" + k*x = f(t) into a state-space model. The parameters given are m = 5 and k = 1, leading to the identification of two state variables: x1 = y and x2 = y'. The participant attempts to establish the state-space matrices, proposing A, B, C, and D matrices but realizes a correction is needed for the A matrix. The final A matrix should reflect the correct dynamics, specifically A = [0 1; -k/m 0], which simplifies to A = [0 1; -1/5 0]. The discussion highlights the importance of understanding state-space representation in control systems.
cb951303
Messages
16
Reaction score
0

Homework Statement



Hi guys/girls

Professor gave this very simple homework where I need to convert the system below to a state-space model.
Mass_spring.png

The system itself is represented by the equation
Code:
m*x" + k*x = f(t)
Where m = 5 and k = 1. Note that, " (doublequote) is a second-order derivative.
Unfortunately I don't have the background to solve it because I slacked too much :redface:

Homework Equations


State-space model that we use is below:
ddfd74546a0e35f9ec054af2ecd3f2fa.png

d0ac09f5cde2ce822ecc3e369692d04b.png


Any help&explanation would be appreciated, thank you.

EDIT: Ok, I've just read the rules and apparently I'm not allowed to as for solutions without an attempt to solve it. Since I can't even attempt, may I ask a good place/source to start?
 
Last edited by a moderator:
Physics news on Phys.org
attempt:

Code:
5y" + 0y' + y = u

since my diff. eq. is second order, I should have 2 state variables:
Code:
x1 = y
x2 = y'
so the state space model's matrixes become
Code:
A = [ 0 1 ]   B = [ 0 ]
    [ 1 0 ]       [ 1 ]

C = [ 1 0 ]   D = [ 0 ]

does it look ok?
 
Dude,

A = [0 1]
[(-k/m 0]

-k/m = -1/5 lol!
 
Thread 'PLL - How to find all the gains of a PI corrector and fix Ki ? MATLAB'
Hello everyone, it's not really for my homework (because I'm not at school anymore) but I'm new and I don't know how to start a new forum. I've never done automatic before and I need help. I have a 2nd ordre PLL on MATLAB, with an NCO and a PI corrector; the PLL works via the Mid/End algorithm (that's part is ok). I need to find the link between the theoretical formulas and their values in the code to find the value of the gain Ki, and possibly that of Kp if it's not correct. Unfortunately...
Thread 'Have I solved this structural engineering equation correctly?'
Hi all, I have a structural engineering book from 1979. I am trying to follow it as best as I can. I have come to a formula that calculates the rotations in radians at the rigid joint that requires an iterative procedure. This equation comes in the form of: $$ x_i = \frac {Q_ih_i + Q_{i+1}h_{i+1}}{4K} + \frac {C}{K}x_{i-1} + \frac {C}{K}x_{i+1} $$ Where: ## Q ## is the horizontal storey shear ## h ## is the storey height ## K = (6G_i + C_i + C_{i+1}) ## ## G = \frac {I_g}{h} ## ## C...
Back
Top