Questions tagged [control]

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Output signal for space-state

I have a space-state system and I need to find the output signal of it. Can anyone here explain to me how to do it? My soluation: is it a right answer?
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Why is phase variable called like that?

I just read about phase variable-form here. ...
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How can to obtain the hughcut, lowcut and bode constant of a bandpass digital filter?

I need to create a bandpass filter amplifier in python; and determine the transfer function, graph the bode diagram, and print the highcut frequency, lowcut frequency, the bode constant and the ...
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Discretization of a controller

The desired control is $u_f=\frac{1+\eta s}{1+hs}a$, where $u_f$ is the feedforward control, $a$ is the feedforward observation and $\eta$ and $h$ are two constant parameters. However, I can only ...
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Are there control loops that attempt to maximize a process variable?

I'm working on Remote-Procedure Call (RPC) server that processes incoming streams of data from clients, and looking for a way to set a limit on the number of simultaneous streams allowed. There is ...
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How to deal with "weird" phase plots in bode diagram when designing a controller

I am trying to design a balance controller for a robot. With MATLAB simulink I arrived at the transfer function between the input and the pitch angle for the robot. I have plotted the bode and Nyquist ...
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Tuning a PID Controller

I have the following transfer function $$10000 \cdot\frac{(s-0.012)(s+1.05)(s-18)}{(s+0.22)^2(s+45)(s+1000)}$$ For which I am trying to tune a PID controller for. I'm using the pidTuner in MATLAB to ...
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Why do we use "error quaternions" for control of attitude?

I'm working on an attitude control system in terms of quaternions, and i'm basing my approach on the book Space Vehicle Dynamics and Control (2nd ed.). If we consider a proportionate controller, i.e. ...
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how to take a second order transfer function without any zeros and represent it using two first order transfer functions

does anybody know how to take a second order transfer function with no zeros (no s terms in the numerator): $$ g(s) = K\frac{\omega_n^2}{s^2 + 2\zeta \omega_n s + \omega_n^2} $$ and represent it using ...
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How to quantify amplitude of oscillations in marginally stable systems?

Transfer function pole on the Imaginary axis indicates that the system is marginally stable which in time domain can be represented as a sinusoidal motion with constant amplitude and frequency of the ...
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Controller in the feedback path?

What happens if the controller of a closed-loop system is placed in the feedback path before the summation point, instead of between the summation point and the plant to control? Are we allowed to do ...
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How does the intuitive notion of causality fit in with control systems?

Edit: By causality, in this question, I do not mean the traditional mathematical definition in the theory o signals and systems; I mean causality as in an intuitive 'what's moving/pushing what notion'....
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Region of root locus not inside the feasible region for a given performance specification

I wanted to plot the root locus for a system, whose plant transfer function is $$ P(s)= \frac{k}{Ts+1}e^{-ts}. $$ A PI controller was suggested for this system, and the task is to find $K_p$ and $K_i$...
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Is it a mandatory condition that complex poles and zeros should always exist as conjugate pairs?

Complex poles and zeros always exist in conjugate pairs?If not always, in which context applicable? https://www.informit.com/articles/article.aspx?p=32090&seqNum=9 The above link mentions related ...
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Transfer function estimation using system identification

I am posting a control system problem here because of this post reference. Question: I have input and output datasets. These are graphically shown below. The blue line is output and the pink line is ...
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Control of a nonlinear static MIMO System

I am currently writing my master thesis and trying to design a controller for my system. However, the system is somewhat unconventional. It has a large number of inputs and outputs, is static, non-...
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Controller design with DQ transform

I'm reading this paper on a 3-phase rectifier control. 3-phase rectifiers are usually connected to 50-Hz or 60-Hz grid. One popular control strategy is to transform the 3-phase currents and voltages ...
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Feedforward disturbance signal compensation

The reference Feedforward control concepts through Interactive Tools says, to minimise the effect of the disturbance $d$ on the process output $y$, a compensator $G_{\text{ff}}=P_3/P_1$ shall be used. ...
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Stabilizing the inverse transform of a system

Currently I am trying to understand an unknown mechatronic system. I used white noise as an input signal and measured the output of the system. Then I estimated a second order SISO transfer function (...
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Why if I place the zero of the lead compensator at lower frequencies, do I obtain a resonance peak?

I am studying control systems, and I am studying the lead and lag compensator. I have seen than if I use a lead compensator for the closed loop transfer function, $T(s)=\frac{s+2}{(s+1)(s+8)},$ with ...
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Measurement delay versus control delay

For a typical conventional control loop (no delay, measurement transfer function is 1) the closed-loop transfer function is $$H(s) = \frac{G_{comp}G_{process}}{1+G_{comp}G_{process}}$$ With an ...
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What does it mean that a zero is slow?

I am studying control systems, and have encountered the definition of a slow zero. I am searching on internet and in books, but I don't understand the meaning this. I know that if a zero is too slow, ...
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Does a RHP zero imposes some limitation in the time domain?

I am studying control systems and I have seen that a non-minimum phase zero imposes a limitation on the bandwidth, which is that the bandwidth has to be lower than the frequency which is half the ...
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Problem in verifying zero blocking property of a zero of a multiple input multiple output system

I have a multiple input multiple output control system, and in particular a two inputs two outputs system. I want to find the zero state direction and the zero input direction of the system, which has ...
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Is it possible to use a control scheme with a delay as prefilter?

I am studying control systems, and in my studies I have encountered the topic of control scheme of the form and I have seen thaht this control scheme is really useful since it is possible to add a ...
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Can a pole at the origin be considered a dominant pole?

I am studying control syetems, and I have studied that the dominant poles of a system are the ones closer to the imaginary axis. Now, consider a system with a pole at the origin. Can this pole at the ...
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Why does the control effort increase if the bandwidth of the system is higher then the bandwidth of the plant?

I am studying control systems and I am focusing on the control effort. I have seen that if I place a pole at higher and higher frequencies, if the bandwidth of the system goes above the bandwidth of ...
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Understand diagram of a process

I've found this diagram in a slide, but i have no backround to properly understand it. Could you explain to me, in simple terms, how this process behaves and what's the purpose of the blocks $z^{-1}$ ?...
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How do I find transfer functions from a state space representation?

Suppose I have a MIMO system in state space representation, for example: $A=\begin{bmatrix} 1 &2 &3 \\ 4&5 &6 \\ 7&8 &9 \end{bmatrix}$ $B=\begin{bmatrix} 2 &3 \\ ...
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Influence of a RHP zero/pole in the frequency response

I am studying loop shaping, and I am looking at loop shaping design with unstable poles and zeros. I have seen that noth unstable poles and zeros introduce limitations in the bandwidth. I have also ...
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Doubt on behaviour of frequency responce of a system

I am doing loop shaping using $H_{\infty }$ approch, and I have a plant with an unstable pole: G = 10/((s+10)*(s-1)); K1 = 4*(s+1)/s; where G is the plant, and ...
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Doubt on the relationship between the sensitivity and the complementary sensitivity function

I am doing loop shaping with the following transfer functions: G = 10/((s+10)*(s+1)); K1 = 0.5/s; where G is the process and K1 is the controller, and If I ...
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How can a stable system have a RHP pole?

I am working with a control system which has an unstable pole in the process. So I have the following transfer functions for the controller and for the process: ...
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2 answers
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Understanding Matlab's Automatic Gain Control function

I am trying to understand the automatic gain control block provided by the communications toolbox. The documentation is here: Documentation My questions are in regards to two of the configurable ...
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Discretizing a Controller with the Backward Difference Method

In the book "Modern Control Engineering" by Paraskevopoulos it's proved how to discretize a generic controller in the form: $G(s)=\frac{Y(s)}{U(s)}=\frac{a}{s+a}$ where $a$ is a constant. Done this, ...
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Doubt on inversion of the dynamics

I am studying control system and I have encountered the topic of the inversion of the dynamics. So I have seen that the ideal situation would be $C(s)=P(s)^{-1}$ but there are some problem with ...
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Lead compensator vs lag compensator?

I already know that lag compensator acts like PI controller and improves steady state and lead compensator acts like PD controller improves transient state but how they achieve their goal? Despite ...
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confusion about poles and zeros of Lead compensator?

I was reading about lead compensator from a website but i am not able to understand how they have extracted zero and pole from transfer function of lead compensator as shown in attached photo? or ...
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6 answers
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Relation between signal processing and control systems engineering?

Control systems engineering and Digital signal processing are both important courses/subjects of electrical engineering But how these two subjects/courses are related to each other?? Also please ...
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Effect of origin poles on stability?

What will be stability if we have only one single pole at origin in s domain?? and what will be the case for multiple poles at origin in s domain?
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Is a good practice to use one PID in rise time and another PID for steady time in order to eliminate oscillations during steady time?

I'm trying to control temperature with PID(Kp,Ki, Kd). During the rise time the system use one PID and when target is reached the system switch to another PID with other parameter in order to ...
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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 +...
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Calculating an in-loop signal as part of a hierarchical control loop

I've got a control system with two feedback paths, with each path going to a different actuator that corrects the error in the system. One feedback path provides feedback at low frequencies, and the ...
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State space equations

I am stuck on this exercise. I don't know how to deal with this squared y in the denominator. What am I supposed to do to obtain state space equations? ex.1 Simplified dynamic model of the steel ball ...
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2 answers
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Control optimization problem

I am running into a problem where I have a control system $S[t]$ that takes a control $C[t]$, so that $$S[t+1] = H(C[t,t-1,...], S[t,t-1,...])$$ the response of the system is the history of controls ...
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