# Questions tagged [control]

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### Desired trajectory generation from transfer function in control theory

I am trying to implement the backstepping techniques for quadrotor described in this article : Backstepping control for a quadrotor helicopter: Madani & Benallegue 2006 Since I am new to the ...
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### PID Tuning for 6 degree of freedom robot with ROS

I'd like to start by saying that I'm pretty clueless about controllers, control theory, or really anything to do with this subject. I'm a programmer, but I'm part of a project involving a 6 degree of ...
44 views

### How to choose sample offset values in timing synchronization for a QPSK demodulator?

I am implementing a timing synchronization loop for a QPSK demodulator. I have chosen to use a Gardner timing error detector, which has often been mentioned. I am about to close my loop and I am ...
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### Difference between H2 control and input shaping

Let us assume a system with external disturbance to reject. The system that is used for controlling has vibrations, that we would like to avoid. We assume moreover that the dynamics are known (10% ...
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### What equations do I need to find the requested parameters?

Consider a filter of the form $$𝐹_{posic}(𝑠) = \alpha_1+\alpha_2e^{-sh}.$$ Find the parameters $\alpha_1, \alpha_2 \in \mathbb R$, and $h > 0$ such that $P_{\theta\phi}F_{posic}$ is an FIR (...
1 vote
66 views

### Controllability matrix is full rank identity matrix

What does it mean, when my system has controllability matrix that is full rank and identity matrix? Having full rank means that the system is controllable, but does the Identity feature of my ...
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### Is it possible to use AMIGO tuning rules with relay control?

I am trying to control a plant with PID using tuning rules such as the Ziegler-Nichols rules. However, it is not always easy just to send a step to your plant source of the image. Another method to ...
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### Understanding an adaptative single neuron PID controller

I only know the "vanilla" use of a Kalman filter and I am currently trying to understand an article available here (the algorithm is presented in the 6 first pages) : Adaptive Single Neuron ...
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### Digital PID controller implementation

I am not sure whether I have chosen correct forum for my question. The question regards the implementation of a digital PID controller. From my point of view it is a kind of digital filter which is a ...
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### What is the point of using this derived PID controller?

Previously, I answer for this PID controller that I want to understand completly. This is used for control the opening $U_n$ of a valve let gas pass and reach a certain pressure (SetPoint). There is ...
162 views

### Tuning Active Power Factor Correction converter works in Simulink, but having trouble achieving the same in DPS

I am trying to tune the Active PF Correction converter current and voltage loop to get a sinusoidal input current. I can get to a voltage reference, but the current looks like this. Reading the ...
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1 vote
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### Confused with special cases of Routh-Hurwitz

When the first column only has a zero we replace is with an $\epsilon$ so we don't divide by zero ahead but divide by the $\epsilon$ then take the limit as it goes to zero. meanwhile if an entire row ...
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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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### 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 ...
72 views

### 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 ...
127 views

### 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. ...
78 views

### 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 ...
145 views

### 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'....
165 views

### 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 $K_i$...
395 views

### 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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### 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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