Questions about the models and theories of control engineering and the application of control theory to design systems with desired behaviors.
0
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0answers
10 views
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 ...
3
votes
0answers
25 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 ...
0
votes
1answer
32 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 ...
3
votes
1answer
57 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
$$\begin{gather}
\dot{r} = v \\
\dot{v} = F/m \\
r(t_0) = 0\text{ m}, $v(t_0) = 0\text{ m/s}, m = 1000\text{ kg}
\...
0
votes
1answer
30 views
Learn thermodynamics before beginning with control engineering ? [closed]
I'm about to start learning about control engineering. But am I advised to learn first Thermodynamics? (Since control engineering has applications in Thermodynamics)
1
vote
1answer
32 views
Cruise Control Project on Toy Car
I finished taking my control theory course, and I want to build an RC car that has cruise control. So I started off with the force analysis, and I got external forces that are constant. For example if ...
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0answers
35 views
Using an unstable controller that gives a stable closed loop performance
I have system with controller (a state-space system with 0 reference input; this is the equivalent transfer function representation)
$$\frac{9.1 s^2 + 73.5 s + 125}{s^2 + 17 s - 30}$$
which is ...
1
vote
1answer
27 views
Using place command in MATLAB using different state representation
I had a transfer function
$$\frac{10s+20}{s^3+10s^2+24s}$$
and I found the state space representation of the above using MATLAB.
Using $place(A,B,[poles])$, I found a gain matrix K that corresponds ...
1
vote
1answer
48 views
How to control a multi input single output heating system?
I am trying to optimize the heat control of a test bench at our facility. The test bench is basically a pipe with an air flow that can be heated up to desired temperature. To heat the air flow up ...
0
votes
1answer
39 views
Transfer function with cancellable zero pole and controllability
I have a transfer function (From Ogata's Modern Control Engineering)
$$\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 ...
0
votes
2answers
35 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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0answers
17 views
2
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1answer
45 views
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)$ ...
0
votes
1answer
22 views
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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votes
0answers
20 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 ...
0
votes
0answers
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_{\...
1
vote
1answer
50 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 ...
0
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0answers
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 ...
1
vote
0answers
25 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}(...
0
votes
0answers
17 views
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 ...
0
votes
0answers
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 ...
2
votes
2answers
48 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 ...
1
vote
1answer
60 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 ...
0
votes
0answers
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 ...
0
votes
0answers
21 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 ...
1
vote
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 ...
1
vote
1answer
25 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{...
1
vote
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, ...
0
votes
2answers
48 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 ...
1
vote
1answer
42 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 ...
1
vote
0answers
23 views
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, ...
4
votes
2answers
48 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 &...
0
votes
1answer
28 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 ...
1
vote
1answer
45 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 ...
0
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0answers
46 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$$
The ...
0
votes
1answer
64 views
Negative gain in Ziegler-Nicholas Oscillation Method?
For a plant G(s), the transfer function is given by:
$$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 ...
3
votes
1answer
83 views
Advantage of anti-windup
What is the definition of anti-windup? How does it impose the constraints?
What are the advantages of MPC and anti-windup over each other?
Does anti-windup guarantee the constraints or does it just ...
3
votes
1answer
46 views
How do I compute/plot the open loop transfer function of a system given its state-space description?
Suppose I have a dynamical system with a continuous time state-space description given by the matrices A, B, C, and D, under full-state feedback u=Kx (where x is the state and x is the control input). ...
0
votes
1answer
34 views
Maximum error in Encoder when discrete sample interval is 2 ms
I am using an encoder having 1000 pulse in one revolution in both edges configuration. I used one method in which number of pulse is counted. What is the error in this case?
Another method is ...
1
vote
1answer
52 views
Is nonlinear control slower than linear control?
Is there any scientific comparison between linear and nonlinear systems?
I often hear that
Nonlinear control is more sluggish than linear control.
which makes sense. But is there any research or ...
0
votes
2answers
53 views
What is the condition of real eigen values other than symmetric matrix?
I have some difficulty to solve this question:
What is the condition for real eigen values other than symmetric matrix?
0
votes
1answer
37 views
Wheel angle for turning
Given a car configuration with a length of L and width of W. If you can give the top left wheel an angle of A to turn A degree how do you derive the angle of top right wheel for turning . I know that ...
0
votes
0answers
37 views
For a variable control chart, how to find the optimal sample size, control limits, and frequency?
I need help to solve this question:
A process has only one assignable cause. The process will run for 20,000 hr continuously
The process generates N units/hour. To take a sample, there is a fixed ...
0
votes
2answers
68 views
How to control the level in multiple connected tanks at the same time?
In a coupled tanks system, what is the control strategy to simultaneously control the level in multiple tanks. In this case the actuators influence multiple control variables. The system is as shown ...
1
vote
2answers
65 views
Where should I start to be a control system engineer? [closed]
I am a telecommunication and network engineer working as a programmer and data analyst. One of my dreams was and still to be a control system engineer and to design and program a smart robots and ...
3
votes
1answer
58 views
Stability of the optimal control law
in linear optimal control,linear quadratic regulator,we have a system of the form: x=Ax+Bu,the optimal control law U is a state feedback,it's a function of the riccati equation solution and the state ...
2
votes
1answer
156 views
Can a neutrally bouyant helium balloon be suspended in air using magnet entrapment?
The above picture is a basic concept of how a levitron toy works.
Could the top floating peace stay entrapped in the magnetic field without having to spin if the edges of the balloon keep the top ...
0
votes
1answer
39 views
Passivity and stability
I read the paper "Bilateral Control of Teleoperators with Time Delay",which is written by Robert J. Anderson and Mark W. Spong. In that paper, they defined passivity of an n-port flow as
$\int^\...
1
vote
1answer
33 views
Skogestad & Postlethwaite, Multivariable Feedback Control: Analysis & Design, Wiley, 2005 Figure 9.10 Why a negative sign on W2?
Yesterday in class this question came up by one of the students in the class. Does anyone know why there is a minus sign in front of the W2 in the figure?
2
votes
0answers
21 views
How to control an underactuated platform with a single servo
What's the best way to control the following type of platform so that it remains balanced and upright?
It's a box supported by a single leg that can pivot at the foot (F) and at the hip (H). The foot ...
