Questions tagged [control-systems]

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6
votes
1answer
208 views

Regarding the choice of cost function in adaptive control - squared error vs absolute error

I did search the question database regarding this question, and although one or two questions came close, they didn't really address my specific question. In adaptive control based on minimizing ...
5
votes
1answer
227 views

Is there a strategy for discrete control of a system with dynamics near sample rate?

I'm trying to control a system where the controller sample rate is physically fixed and the plant has significant dynamics on the same order as the sample rate. I understand that one would prefer to ...
4
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0answers
196 views

Digital control: Exercise solution

Can you help me (show me how) to solve the following exercise? For the process with transfer function $G(s)=e^{-2s}/(s+1)$ design a digital controller with sampling time $T_{s} = 1$ that meets the ...
3
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0answers
1k views

How do I check controllability and observability using Gramian matrixes?

I have a pending exam and this is one of the must-know questions. It will be about checking controllability/observability of a simple MIMO linear system, using Controlability Gramian/Observability ...
3
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0answers
105 views

Optimal inference for nonlinear state space models

When considering a linear-Gaussian state space model, it is often referred that, optimal inference is tractable which is very rare in state space models. When considering a nonlinear state space model,...
2
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0answers
24 views

General tips for PID tuning of super low-friction actuator?

I realize this question is not directly related to signal processing, however, it's relevant to system analysis which is relevant to most signal processing engineers. There's also no good alternative ...
1
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0answers
43 views

Position Kalman Filter fails to track a constant-acceleration path

I'm trying to build a discrete Kalman Filter that fuses accelerometer (acceleration) and GPS (position, velocity) measurements. However, I'm finding that my filter can't properly track a constant-...
1
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0answers
36 views

How can I design a PI controller for a closed loop system, which requires a bandwidth equal to the natural frequency and a set Phase Margin?

For a school project I have to hand in a small report on a this problem. I've been studying so much for it but right now I'm just mixing up everything I've seen and just don't know where to start. I'd ...
1
vote
2answers
203 views

What are poles and zeroes (with respect to the inputs and outputs of a system)?

I get it, about poles and zeroes, when we talk in terms of the transfer function. But, if the transfer function is the ratio of the output to the input, then if the input signal is zero, then the ...
1
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0answers
45 views

How can I find the transfer function from this Bode diagram?

I've been given this bode diagram : I've been asked to find the transfer function only by using the bode diagram. It's the first time I'm doing this so here's what I thought. The starting value is ...
1
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0answers
2k views

Deriving the transfer functions of a heating system

I'm tying to develop a model for a heated system that consists of a small steel block (~25 sq. in.) with a heating element embedded in it. The block acts as a sort of hot-plate that is used to deform ...
1
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0answers
33 views

Perturbation test for a real plant

How should we conduct a perturbation test for an LTI unknown system by perturbing the input to see the output response i.e. How many different perturbation step size should be given to the input?
1
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0answers
74 views

Parameter identification for PI controller

I have a PI temperature controller being used in experiments, which I am also trying to simulate. However, using the proportional gain and integral time as used in the experiments gives different ...
1
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0answers
118 views

Does the integrator in a PID controller removes the disturbance?

I am reading "Small Unmanned Aircraft: Theory and Practice" (page 7). We have the following Transfer Function (TF): $\phi(s)=\frac{a_{\phi 2}}{s(s+a_{\phi 1})}(\delta_a(s)+\frac{1}{a_{\phi 2}}d_{\phi ...
0
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1answer
10 views

External/Internal Description of a System

When an LTI system is NOT completely controllable/observable, does the linear differential equation governing the system give the internal or the external description of a system?
0
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0answers
25 views

what is the co-variance of system output cooresponding to a non-iid random variable

Consider the following system.$\DeclareMathOperator{\sign}{sign}$ $$ \begin{aligned} &\dot{e_1}=c_1e_1+c_2e_2+\eta\\ &\dot{e_2}=c_3e_1+c_4e_2-c_5 \sign(e_1)+a \eta \end{aligned} $$ which $\eta$...
0
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0answers
22 views

How to integrate and differentiate sampled signals?

I am working on a control system which is defined by the equation. As you can see,the equation is in continuous state. $T_i$ = integral time and $T_d$ = differential time which are both constants ...
0
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0answers
16 views

Finding gain on root-locus

I have to design a compensator using root locus for the system $G(s) = \frac{1}{s\cdot(s-4)}$ that follow the following criteria: $op\% \le 5\%$ $t_{2\%} \le 4s$ So I started computing $\zeta$ and $...
0
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0answers
18 views

Comparison Between Mahoney Filter and Kalman Filter in Euler Angles (Yaw, Pitch, Roll) Estimation

What are the advantages of Mahoney Filter over Kalman Filter for Euler Angle (Yaw, Pitch, Roll) estimation? Could anyone compare them for Angular State Estimation? Resources Mahoney Filter ...
0
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0answers
65 views

Block diagram reduction with multiple inputs

I need to reduce the diagram, when each input is 0, I can do when d=0, however i'm finding it a little difficult when r=0. I have solved the exercise using a signal flow diagram and the solution is ...
0
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0answers
38 views

On $H_\infty$ norm for transfer function

For a given scenario in the context of control system, I'm trying to investigate how the $H_\infty$ norm can be calculated for a transfer function as follows: $$G(s)= \frac{w_n^2}{s^2 +2\zeta w_ns +...
0
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0answers
23 views

How to move a linear block before an Integrator block?

I have the following discrete time blocks which acts as a decimation filter. My objective is to linearize the piecewise linear outputs using $O$ and $G$; the purpose of these two variables is ...
0
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0answers
33 views

system identification: MATLAB tfestimate gives different results for different Fs

So I have an experimental data; A is a chirp signal (sweep sine wave) and B is the response of the system. I identify the system as follows in MATLAB: ...
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0answers
15 views

What are simple direct adaptive control algorithms?

I am going into this blind. Was wondering if someone can point out some resource on direct adaptive control algorithms?
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0answers
61 views

How to compare the similarity of 2 transfer functions

I'm working on a power systems where I have 2 linearized transfer functions. The first transfer function corresponds to the no-load case and the second transfer function corresponds to the full-load ...
0
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0answers
39 views

Analog to digital controller- What sampling rate?

I'm studying about the design of controller in digital control systems. Right now I see the method in which I design my controller in the s domain and then convert it to the z domain. However, in ...
0
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0answers
43 views

Which equation should I use to compute the Extended Kalman Filter?

Compute the Extended kalman filter can be done in several ways. The first one compute the convariance matrix $P(t)$ from the Riccati Equation: $$\dot{P} = F(t)P(t) + P(t)F^T(t) - P(t)H^T(t) R^{-1}H(...
0
votes
2answers
350 views

Design discrete controller for zero steady state error

I have the following system where $$G(s)=\frac{0.5}{s+1}+\frac{5}{s+10}$$ How can I design the C(z) controller so that the steady state error for a step input r(t)=1(t) is zero? I know that this ...
0
votes
2answers
203 views

Feedback systems & oscillations

The transfer function of feedback system is: $$ \frac{V_{\rm out}}{V_{\rm in}} = \frac{A}{1+Af} $$ Where $A$ is the open loop gain, and $f$ is the feedback gain. Now for oscillation to happen, $Af$ ...
0
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0answers
78 views

Control of pendulum (crane trolley)

I need to control crane trolley (pendulum), I have state space representation as: $ A=\begin{bmatrix} 0 & 1 & 0 & 0 \\ 0 & 0 & \frac{m_b}{m_j}g & 0 \\ 0 & 0 & 0 &...
0
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0answers
96 views

phase locked loop

I have seen that to get the phase angle of a signal, we have to use PLLs. this PLL is modeling in order to get the phase angle about one frequency, which is the free running frequency of the VCO. If ...
0
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0answers
275 views

Troubleshooting PID controller

I'm developing a PID controller to control the position of a laser beam. The position is measured using a Position Sensitive Device (PSD). I modeled the plant according to the manufacturer specs and I'...
0
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0answers
559 views

What is pulse train filter?

I have recently seen some code written in modelling tool like Simulink, ASCET which uses PT1 filter? Why do we use a pulse train filter? What is the difference between FIR, IIR, Chebyschev, ...
0
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0answers
129 views

PID Control - process variable / setpoint

I'm trying to design a PID controller but I have a problem in the following case: The process variable can only be between 0 and 1. The setpoint can be close to one, for instance 0.97. Hence the ...
0
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0answers
26 views

System indentification different inputs

I have peformed different form for input/output relation to determine a system, but seem to be missing some theory which input will be the most will excite enough modes such that the models which i ...
0
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0answers
70 views

Perfect system identification or am i doing something wrong?

I am using MATLAB to identify a system. The problem with my method is that my result is perfect. I get a nearly 100% fit, which make me wonder if what I am doing is correct. I feed a sine sweep with ...
0
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0answers
28 views

Stability of an unstable system using nonlinear element. Is it possible or not?

Say there is a system with open-loop transfer function G(s)=1/(s−1) . The system is definitely unstable. If I put any nonlinear system in cascade with G(s) and from the output, a negative unity ...
0
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0answers
50 views

construct 2-state observer

I have position $\theta(s) = \frac{s^2+1}{s^4+2s^3+3s^2+4s+5}$ and velocity $\dot\theta(s) = \frac{s(s^2+1)}{s^4+2s^3+3s^2+4s+5}$. How do I construct 2-state-observer with sampling time $T_s$? $\...
0
votes
1answer
49 views

input output read/write frequency

I am trying to identify a system based on input/output response and thereby estimate a transfer function. I generated a frequency sweep function in Mathematica which gives me the discrete values of a ...
-1
votes
1answer
241 views

Step response of feedback system

We have a feedback system F(s) as in this figure: and this is the step response of G(s): and H=10. F(s): We got the root locus of the system F(s) as this: then we determined the gain at ...
-1
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1answer
265 views

Describing Function for non-symmetric Saturation Model

Let's talk about a standard saturation model: with bounds $bound_{lower}$ and $bound_{upper}$. So in this example the output $y$ will be: \begin{equation} y(u) = \begin{cases} bound_{lower} ...