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Questions tagged [control-engineering]

Questions about the models and theories of control engineering and the application of control theory to design systems with desired behaviors.

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How to get value of K1 and K2?

I am working on Passivity based controller of boost converter and refer below paper. https://drive.google.com/file/d/1S2Yql5dM3TzbiW14VqV20kZVt6BUgx7b/view?usp=sharing you can see paper. i try ...
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1answer
71 views

Which is the best extendable pole?

Which of these poles would be straighter and stronger then the others? 1) STEM ( Storable Tubular Extendible Member), a pre-stressed piece of thin metal that could be rolled up like a carpenters ...
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30 views

load in a stepper motor

I want to move a 7 kg object linearly, using a stepper motor. How can I determine the torque required by a stepper motor depending on the load?
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2answers
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Books for learning PID control? [closed]

I am aiming to program a quadcopter flight controller as a personal project. To be able to do this I understand one of the fundamentals is a PID control system . So my question is does anyone have ...
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How are all LTI systems also dynamical systems?

How are all LTI systems also dynamical systems? I understand that LTI systems are linear and time invariant and that dynamical systems describe how one state develops into another, but how would this ...
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1answer
55 views

What is the most common control method in Underfloor heating?

I am trying to research the common methods on an underfloor heating system that are available in the market. I know there are usually, On/Off control to control the flow of water into the pipe ...
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1answer
17 views

State observer for speed estimation from encoder

I try to implement a state observer (Luenberg Observer) to estimate the speed of my motor. Only the absolute position of the motor can be measured and I want to take into account also the target ...
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1answer
33 views

Zeros of a Trransfer Function

I would be grateful if someone could explain me what does the value of zeros of a transfer function tell about the dynamics of the system.
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32 views

how to filter model-free observations (e.g. Kalman filter)

Before asking a question, I have no background knowledge of engineering. So I have no idea about these issues like control or signal engineering. (Also, I'm not good at using English. sorry for that.) ...
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1answer
37 views

Programming a gas mass flow controller rig

I'm trying to upgrade a multiple gas flow controller, which must be capable of controlling the mass flowrates of three gases independently through one outlet line to our system, and am in need of a ...
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1answer
31 views

The relationship between the I control and the stability margin

While I'm reading the paper, it said "The I control can makes the phase lag, so it can makes stability margin reduced." Words are not same as that, but the meaning is the same. How the I control ...
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33 views

What is the connection between PID and feedforward controllers?

They are tightly connected as some concepts of feedforward is based on PID algorithms, and both of them are control systems. But when I see a phrase such as "Feed forwards augment PID control", I'm ...
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1answer
50 views

Control of second order undamped system

I have the following differential equation: $$\ddot{\psi_t} + \omega^2 \psi_t = \omega R_s i_f - \omega u_f + \dot{u}_t - R_s \dot{i}_t$$ where $w$ is the electrical speed of the motor. I have ...
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If I replace a flow orifice with a Coriolis flow meter of the same size do I need to worry about pressure drop with the new Coriolis meter?

I have a 3 inch line with a 1.5 inch flow orifice. If I take out the flow orifice and put in a 1.5 inch coriolis meter will the pressure drop be the same or better with the new coriolis meter than ...
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Limit for poles&zeros in System Identification

When doing system identification it is not possible to identify dynamics (i..e poles) related to frequencies higher than the excited signal. Let's say my excitation signal has a highest frequency ...
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1answer
38 views

Constructing a block diagram for amplitude control of an oscillator

I'm building a Wien Bridge oscillator. The oscillation part works just fine, but it currently limits on the supply rails. I want to add amplitude control, so I've added a precision rectifier which ...
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1answer
46 views

simulation of an attitude optimal Backstepping controller based quaternion for a UAV in MATLAB

I'am trying to implement this open access research article Attitude Optimal Backstepping Controller Based Quaternion for a UAV I did not find the same result in this paper Can anyone tell me where my ...
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1answer
76 views

what's wrong with this robust control scheme?

I'm learning how to control a double integrator with $H_\infty$. my model is simply $$\begin{gather} \dot{r} = v \\ \dot{v} = F/m \\ r(t_0) = 0\text{ m}, $v(t_0) = 0\text{ m/s}, m = 1000\text{ kg} \...
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1answer
31 views

Learn thermodynamics before beginning with control engineering ? [closed]

I'm about to start learning about control engineering. But am I advised to learn first Thermodynamics? (Since control engineering has applications in Thermodynamics)
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1answer
46 views

Cruise Control Project on Toy Car

I finished taking my control theory course, and I want to build an RC car that has cruise control. So I started off with the force analysis, and I got external forces that are constant. For example if ...
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37 views

Using an unstable controller that gives a stable closed loop performance

I have system with controller (a state-space system with 0 reference input; this is the equivalent transfer function representation) $$\frac{9.1 s^2 + 73.5 s + 125}{s^2 + 17 s - 30}$$ which is ...
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1answer
30 views

Using place command in MATLAB using different state representation

I had a transfer function $$\frac{10s+20}{s^3+10s^2+24s}$$ and I found the state space representation of the above using MATLAB. Using $place(A,B,[poles])$, I found a gain matrix K that corresponds ...
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1answer
48 views

How to control a multi input single output heating system?

I am trying to optimize the heat control of a test bench at our facility. The test bench is basically a pipe with an air flow that can be heated up to desired temperature. To heat the air flow up ...
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1answer
40 views

Transfer function with cancellable zero pole and controllability

I have a transfer function (From Ogata's Modern Control Engineering) $$\frac{s+2.5}{(s+2.5)(s-1)}$$ and the theory says the system has a pole zero cancellation and is uncontrollable. They said that ...
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2answers
50 views

LQR control and system dynamics linearization

I recently finished a project that simulated the dynamics and control of a 6DOF quadcopter model using a state-space LQR control approach, but I had a few questions that I wanted to ask that might ...
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Does the controllability of nominal system imply the controllability of the actual uncertain system?

Given a system dynamics \begin{equation} \dot{x}=A(p)x+Bu, \end{equation} where $A(p)$ is the uncertain system state matrix with the nominal matrix being $A(p_0)$. The uncertainty in $A(p)$ ...
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1answer
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How to identify the time delay of manipulated variables which are important to the final quality of polymer product

In a polymer production process, there are a lot of manipulated variables(MV) such as temperature ,pressure , or level of reactor that affect the quality of my polymer product. However, it usually ...
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23 views

Nonlinear state space model example

Is there any (preferably well-known) example of a nonlinear state space model of a system in the following form? $x(k+1)=Ax(k)+f(x(k))+u(k)\\ y(k)=Cx(k)$ where $f(\cdot)$ is a nonlinear function of ...
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20 views

Doubt regarding relation between maximum of $||x||$ and $x^TAx$ with regards to attitude dynamics

I was dealing with 3-DOF attitude dynamics of rigid body and wanted to comment upon the following defined function $F$ at its maxima. Consider $F \in \mathbb{R} : F(e_{\Omega}(t)) = \frac{1}{2}e_{\...
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1answer
55 views

Order of a transfer function and its properties

I hope this is the right place to ask since I couldn't find a control systems SE. Lets say we have the transfer function $P(s) = \frac{1}{s(s+15)(s+10)} = \frac{1}{s(s^2+25s+150)}$(completely made up ...
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19 views

Separation principle for a linear system with disturbances

In publication Mayne, David Q., et al. "Robust output feedback model predictive control of constrained linear systems." Automatica 42.7 (2006): 1217-1222. it is ...
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26 views

Extended Kalman Filter formulation

For a nonlinear system, $$ \begin{align} &{\boldsymbol x}(k+1)={\boldsymbol f}({\boldsymbol x}(k),{\boldsymbol u}(k),{\boldsymbol w}(k)) \\ &{\boldsymbol y}(k)={\boldsymbol h}({\boldsymbol x}(...
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Slip efficiency with optimal control inputs

I have developed an equal slip controller in order to maximize the slip efficiency of a tire. Slip efficiency is a component to traction efficiency that is formulated as followes: $$\eta_t =\frac{F_x ...
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17 views

Controller design for a thrust angle constrained tracking for a 3-DOF system

For the given system: \begin{equation} \begin{aligned} \dot{e_x} &= e_v \\ m\dot{e_v} &= mge_3 - m\ddot{x_d}(t) - f \end{aligned} \end{equation} which is the translational part of position ...
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2answers
49 views

Requirements for realtime control

What are the requirements to call a controller real-time? What are the entire standards for that? I do not think that just rendering the output quickly before the sampling interval passes is ...
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1answer
100 views

Kalman filters vs. state observers

What is the difference between a state observer and a Kalman filter? Having implemented various types of Kalman filters, I'm still a bit confused, mainly because state observers require the selection ...
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52 views

Can a quadrotor track a perfectly horizontal and straight trajectory?

We know that the only control action provided by a quadrotor system is through the propellers. Now, assume that I want to track $x(t), y(t), z(t) = (t,0,0)$. Can we ever develop a controller which ...
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22 views

Equal prediction and control horizon for nonminimum phase systems

In paper, Lee, J.H. and Yu, Z.H., 1994. Tuning of model predictive controllers for robust performance. Computers & chemical engineering, 18(1), pp.15-37. They have proposed an MPC tuning ...
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1answer
20 views

Maximum MPC prediction horizon for an unstable plant

In the following book, Model Predictive Control ToolboxTM (User's Guide) Alberto Bemporad Manfred Morari N. Lawrence Ricker At page 1-6, it has been ...
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1answer
26 views

impulse input and discontinuity in initial condition after

Consider a dynamical system as bellow that is subjected to an impulse input: $\sum_{n=0}^N {a_n x^{(n)}}= f_0 \delta(t-t_0)$ the initial values are non-resting (all non-zero): $x(t_0^-)=x_0\hspace{...
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1answer
30 views

Model Predictive Control and Numerical Integration Schemes

When simulating systems of ODEs, I'm used to always using a numerical integration scheme to propagate the equations forward in time, such as simple Euler integration or Runge-Kutta methods. However, ...
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2answers
54 views

MPC highest sampling time [closed]

What is the highest sampling time ever applied in Model Predictive Control (MPC)? For an HAVC (Heat, Air Ventilation, and Cooling) it can go to hours. But, I am looking for a sampling interval in ...
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1answer
43 views

Are linear controllers inadequate for nonminimum phase systems?

Based on the following publication: Kouro, S., Perez, M.A., Rodriguez, J., Llor, A.M. and Young, H.A., 2015. Model predictive control: MPC's role in the evolution of power electronics. IEEE ...
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Robust linearization

In the following paper: Kuhne, Felipe, Walter Fetter Lages, and JM Gomes da Silva Jr. "Model predictive control of a mobile robot using linearization." In Proceedings of mechatronics and robotics, ...
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51 views

How do I invert a system in state space form?

Suppose I have a system described in state-space form. Can I invert the system (swapping the roles of the input $u$ and output $y$)? If we start with: \begin{align} \dot{x} &= A\,x + B\,u \\ y &...
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35 views

How to improve reference tracking using state feedback?

Suppose that I have a state-space system {A, B, C, D} and a gains matrix K computed via LQR. I would like to track a reference signal x_cmd. I do so by using the control law u = -K(x - x_cmd), where x ...
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2answers
63 views

How do I 'fuse' together two different kinds of data to get a final result?

I am building a robot (2 powered wheels and one ball bearing). The problem is that I can't seem to make it drive straight. I literally find it impossible, I have been trying for weeks. Currently I am ...
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47 views

Is the following system considered to be stable or unstable?

For a plant G(s), the transfer function is given by: $$G(s) = \frac{(10s+50)}{s(s^2+20s+2500)}$$ the PID parmeters are given by: $$K_p=5135$$ $$K_i=6.731$$ $$K_d=0.01475$$ $$T_f=8.57e-05$$ The ...
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1answer
68 views

Negative gain in Ziegler-Nicholas Oscillation Method?

For a plant G(s), the transfer function is given by: $$G(s) = \frac{(10s+50)}{s(s^2+20s+2500)}$$ Using Ziegler-Nicholas method to get the parameter: $k_p = \dfrac{-1000}{3}$ and $w =-28.868j$. Is it ...