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Questions tagged [control-system]

A system that may be electronic circuits or even software that uses control theory (principally differential equations) to control an output by monitoring various aspects of the system under control and varying inputs all towards meeting a defined goal. Some famous examples are controlling a rockets thrust angle to ensure directional control.

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How do I plot Bode Plot this transfer function?

$$G(s) = \dfrac{K \cdot (1 + 0.2s) \cdot (1 + 0.025s)}{s^3 \cdot (1 + 0.001s) \cdot(1 + 0.005s)}$$ Plot an asymptotic bode plot. Determine gain and phase margins. Comment on stability. How do I plot ...
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3answers
33 views

Obtaining Plant Input data from System Identification (PID)

I'm trying to obtain a mathematical model from a physical plant using MATLAB. Using the system identification tool you need the plant input and output data. I'm struggling to match the theory to my ...
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1answer
41 views

Gain deficit and phase margin at crossover

I went through an exercise of the following specifications: A voltage mode buck converter working in CCM mode works with: \$V_{in}\$ min = 10V, \$V_{in}\$ max = 20V \$R_{load}\$ min = 2.5 ohm \$R_{...
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1answer
43 views

how to control state space when it is not controllable?

I have the matrix A and B and I computed the controllability matrix and found the rank is lower than n. I know I can't apply pole-placement , how else can I solve the system? n is the order of A
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43 views

Transfer Function [ the transfer function of the feedback stage? (Optical sensor and the lm2917) ]

I have to make a control system that maintains a constant speed of a small car prototype using a DC Gearmotor regardless of external disturbances such as slopes (small slopes). For the development of ...
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31 views

Calculating input voltage required for a series of capacitors to reach a a certain voltage in a certain time

just had a question regarding a system of capacitors. Its from the EE263 Introduction to Linear Dynamical Systems, Stanford University, 2008 Prof Boyd. If I have the step response and eigenvalues of ...
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1answer
58 views

What is the purpose of the capacitor in this circuit?

Is the purpose of the capacitor, C1, to filter out any possible DC component that the input signal has?
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1answer
42 views

How does force feedback [hardware] work?

Force feedback steering wheels are fairly common, but I don't understand how they work. Specifically, how does a "direct drive"($$$) steering wheel apply a force one way while moving in another ...
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2answers
169 views

What is the difference between these two op-amp circuits?

I don't understand why when we design a proportional amplifier, the feedback has to be negative. When I run the simulation in simulink I get the same result for both circuits.
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2answers
78 views

Power Supply : How to keep SMPS always above the post-regulator that follows it

I'm trying to find a way of building a new power supply for my workshop, in order to keep it small and not so hot I will be using a spare xformer to step down mains to 24v and then a variable buck ...
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2answers
64 views

Sluggish step response of control loop

I have a question regarding the PI controller. Lets say I have an actuator via which I control some plant. The control signal at the output of the PI controller is at its maximal realizable value. So ...
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4answers
484 views

Circuit Analysis: Obtaining Close Loop OP - AMP Transfer function

Trying to figure out the Close Loop System transfer function of an op-amp, however the math isn't working out as it should. Circuit In question: simulate this circuit – Schematic created using ...
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1answer
55 views

What is the difference between 'x' and 'plus' symbol in the block diagram

Generally speaking, what is the difference between the 'x' and the 'plus' symbol in a closed loop block diagram? For example, in (https://ieeexplore.ieee.org/document/6983570) , what's the ...
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1answer
59 views

How do I calculate this inverse Laplace Transform

I have this transfer function and input, and I have to manually calculate what the systems response will be. The transfer function is: and the input is: I multiplied the two functions and used ...
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1answer
134 views

Stability of a PLL

I try to design a analog PLL. I use a doubly balanced mixer as phase detector and a VCXO. The reference is a benchtop signal generator. So I currently try to design the loop filter, and I struggled a ...
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2answers
56 views

buck converter current control - how?

I am interested in understanding better how the regulation for a buck converter works, I don't understand it now and havn't found litterature really explaining it so far, so I am asking you here. The ...
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0answers
67 views

CANopen SYNC object and synchronous window length

In CANopen specification there is an object called Communication Cycle Priod [1006h]. This is the time interval between two consecutive SYNC objects. There is also another object called Synchronous ...
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3answers
912 views

In which way proportional valves are controlled solely by current?

Proportional valves are drived by current because we need a steady force and since resistance changes with temperature if they were driven by voltage this force wouldn't be steady. Ok, this is what I ...
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16 views

Boost converter load regulation

I am currently building a boost converter with PID control to control the output based on the discharge. The output will be fed into a DC/AC converter which, ideally, will power different loads. As of ...
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22 views

How to treat poles with imaginary part when using root locus angle criteria - what is the angle to use?

Context: In the process of designing a phase-lead compensator for a system, I have used the design requirements to find the ideal locations for my closed-loop (CL) poles, have picked a place for a new ...
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1answer
64 views

Confusion of terminology for control systems

I am confused about the following definitions (if there are any): Reference input reference signal setpoint reference I don't understand specifically what they are referring to. Do they refer to ...
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0answers
98 views

Optimum number of CANopen nodes in a CAN bus for motor control

I am studying about the CANopen implementation in a motion control work. CANopen is a protocol over tha CANbus. It is seen that, in the CANopen specification, theoretically at most 127 nodes could be ...
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17 views

Reset control systems - Reduced overshoot (Swing)

The following figure shows a Two-step Incremental Sigma Delta/Zoom ADC where the feedback DAC is adjusted based on the result of the coarse conversion. I am interested in the signal that is injected ...
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4answers
91 views

Effect of RHP zeros on stability

Why do zeros in the right half of the \$s\$ plane reduce stability (i.e., gain / phase margin)?
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83 views

design a modular system, choosing bus and backplane

Our team has developed a several controller boards for our current Projects for over three years. With little modifications we have used this board in several projects so far. Its structure is as ...
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1answer
61 views

Moving summing block before integrator

I wanted to move the summing operation (+10) that I perform before the integrator block as shown below: (MODEL-1) I check in this wikibook page - https://en.wikibooks.org/wiki/Control_Systems/...
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3answers
79 views

The meaning of Bandwidth

What is the physical interpretation of "Bandwidth" in control systems not in filters? i.e What is the relationship between Bandwidth of a system and stability of a system??
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2answers
59 views

how to find frequency of oscillations if a order three system given

Frequency of oscillation in rad/sec of a unity feedback system having open loop transfer function G(s)=K/s^3+3s^2+4s+3 is
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4answers
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Motor fader PID control

I'm trying to control a motorized fader (linear slide potentiometer) using an Arduino. PID control gives good results for "jumping" to a specific target position, but tracking ramps is a problem, it's ...
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1answer
72 views

Determining Number of states in State Space Modeling

I want to use state space modeling for representing the following circuit system. However, I am unable to decide the number of states. I am able to describe the system with a set of three equations. ...
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69 views

Design of a lead compensator with root locus in matlab

For the transfer function G(s), I tried to design a lead compensator for the function to have a response to the step with the following specifications: Overshoot= 10%; Ts (2%) = 5s. When I simulate ...
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55 views

Guidelines and design considerations for designing a controller for a grid tie inverter?

I'm working on designing a controller for a grid tied inverter. I'm not able to find a suitable reference or book that might help in this case. What I have understood now is: There must 2 loops (...
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59 views

PI or PID vs Manual Controller design using Control theory

Why should we design a controller manually using Bode plots and control theory instead of using PI or PID controllers and tune them? Or more specifically when should I design a controller and when ...
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3answers
107 views

Root Locus, Gain in Feedback Loop. Need help

So this is the system for which I have to draw a root locus if 'K' changes from 0 to infinity. The problem for me is that root locus is drawn for open loop transfer function but 'K' is in the feedback ...
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2answers
74 views

Does the stability of an LTI system depend on the input?

Consider a system \$G(s) = \frac{1}{s}\$. It is marginally stable, as it has its only pole at \$s=0\$. However, if we apply a step input, the output is \$ tu(t) \$, which turns out to be unstable. ...
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1answer
50 views

PI controller - DC voltage regulation

I a voltage source converter, in order to control the DC-Bus voltage a PI controller can be used. The control method is illustrated in the figure below: I would like to ask why the input of the PI ...
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1answer
98 views

Constructing bode plot from experimental data and constructing a transfer function

I've been trying for a few days to convert an experimentally obtained (frequency against magnitude and frequency against phase) graphs to a bode plot and then construct a transfer function from the ...
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1answer
42 views

How do you reduce this simple system diagram for the sake of doing algebraic manipulation?

My guess is that since H(s) is parallel with 1(s) we'd do A(H - 1)? But this is my first ...
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What are some techniques to troubleshoot a second order sigma delta loop?

I have designed a slightly modified second order (3-bit) multi-bit incremental sigma delta modulator (IDSM) in simulink (system level). The SNR that I get is 45dB, which is not as expected. But ...
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34 views

Finding the memory polynomial model coefficients

I want to build a memory polynomial model given that I know the corresponding output signals for known input signals. What is the easiest way to find the coefficients of it? And how do we take the ...
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1answer
51 views

How to plot root loci in z plane

How to plot root loci of loop gain G(z)= k/(z-0.5)(z-0.5)(z-0.5) in z plane?
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113 views

How to use the Root Locus design method to improve the transient response of my system?

By closing the loop, I need to design a controller in the feedforward path to minimise the effects of the two pairs of dominant poles of the 5th order transfer function. Use a pole-zero cancellation ...
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1answer
66 views

rlocus() - Not enough input arguments in MATLAB 2018a

I am following this tutorial on root locus methods and when writing: syms s sys = 1/(3*s^2 + 2*s - 1); rlocus(sys) I get: Error using rlocus Not enough ...
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0answers
43 views

How do I calculate a PID controller gain for a certain damping coefficient?

I have a third order process and I have to design a PID controller by cancelling out the two most dominant poles of the process. The process transfer function is: The controller is of the form, where ...
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0answers
35 views

Steady state error due to disturbance

I was trying to solve a question from the 2004 GATE IN paper, I solved it this way, Now, the book is giving a different solution, I'm pretty sure my way is correct since they pulled the "standard ...
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0answers
23 views

Difference in feedback DAC levels between first and higher order Multibit sigma delta modulators

My objective is to understand the difference between first and higher order Multi-bit sigma delta modulators in terms of DAC feedback signals. I have a setup of 3-bit incremental sigma-delta ...
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25 views

Designing a CCM Boost PFC rectifier circuit

I am working on designing a CCM Boost PFC rectifier circuit, supplying up to 2.8kW at 400Vdc nominal, while taking 230Vac, 50Hz controlled via negative feedback in the average current control mode. I ...
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0answers
33 views

What is the meaning of the sensivity, of the open loop transfer function, being -1 regarding the non zero pole?

I have to calculate the sensivity of this transfer function regarding the pole s=-10. I used the formula below, and I got the value of -1 but I do not understand its meaning. I replaced (s+10) with p ...
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2answers
73 views

Meaning of transfer function in s evaluated at a complex number

From the pole-zero plot, you can compute the system frequency response by assuming a locus of test points along the \$j\omega\$ axis. Figure from: http://web.mit.edu/2.14/www/Handouts/PoleZero.pdf \...
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2answers
74 views

Nyquist Stability Criteria

Find the stability where: Find the stability: \$ G(s)= \frac{(s+3)(s+5)}{(s-2)(s-4)}; \$ \$ H(s)= 1; \$ I run this code in matlab: ...