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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Meaning of energy method in control theory

What qualifies a energy method in the context of control theory? Citing from a paper to give the context in which this expression came to my attention: One of the challenging problems of the double ...
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18 views

Auto-tuning PI controller with maximum sensitivity

I am trying to design an auto-tuning controller in matlab with the help of the paper from Astrom and Hagglund: Design of PI Controllers based on Non-Convex Optimization* (1998). They use the maximum ...
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How does a digital controller's sampling period dictate the system's actuation requirements?

When selecting an actuator for a controls application - e.g. choosing a servo motor for a self-balancing robot - I understand that it's important for the actuators to have fast enough dynamics that ...
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Robotics Performance Requirements - Autonomous Vehicle [closed]

Say we are developing an autonomous vehicle. Our vehicle must detect and respond to stop signs. How do we define performance requirements for this safety critical task in regards to correctness?
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39 views

Closed loop guidance and control: how to tune a system with multiple feedback controllers?

I'm trying to design a closed-loop guidance system for rockets - something that can be implemented in Kerbal Space Program, for example. To do this, I'm following the design process described in ...
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Designing Block Diagrams For Control Systems

I'm looking for good software to design control systems, and more specifically to neatly design "block diagrams" for control systems. Is there something like that?
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62 views

Changing fields from mathematics to control engineering [closed]

I did my undergraduate in maths and physics and will be working in control theory for my future job. Not to my surprise, my engineering background is rather lacking. I have taken a look at materials ...
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24 views

Can i switch negative feedback to positive feedback in PID control?

I am learning Control Theory and i have a confusion about whether the following PID controllers are interchangeable or similar. Are they equivalent? Why? Is there any difference in how i would ...
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55 views

Is this a PID cascade control loop?

I'm working on a balancing robot. I'm familiar with the simple PID control loop but i can't understand this PID control loop. Is this actually a cascade control loop? The programming states that the ...
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43 views

Interpreting Nyquist plot

When implementing the control for my application I got this Nyquist plot which made me flabbergasted. If I zoom on the point $-1 + 0j$ I get the following image How do I interpret this contour going ...
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38 views

Difference between Hysteresis, low pass filter and deadband in control theory?

I am trying to understand the fundamental difference between the following terms in the context of control systems: Hysteresis Low pass filter Deadband Are these just fancy names that can be ...
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1answer
83 views

I have a problem with my representation of roll in Simulink

I am currently an engineering student and a member of the aerospace club of my engineering school (ESILV) which is called LéoFly. We’re a team of 12 students and are building a Fusex (...
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22 views

How to find Performance assessment (IAE and ISE) of a PID Controlled system?

The Integral Absolute value Error (IAE) and the Integral Squared Error (ISE) is to be analysed. A PID Controller is given as follows: ...
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26 views

PI controller for second order system

I have a second order system and I need to control it using a PI controller. I need to select the parameters of the controller in order for the system to satisfy a less than 10% overshoot requirement ...
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1answer
44 views

Stabilization of telescope on gimbal using data from encoders and gyroscope

I'm designing a control system for a balloon-borne telescope experiment. As the balloon is constantly moving and the gondola is rotating, I want to stabilize the telescope which can be controlled in 3 ...
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45 views

How to grind into concrete ( not core drill )

I have a very specific and weird task I need to accomplish. I have a concrete wall that I need to get samples of the concrete dust to grind and get them tested, i plan on using a plunge router with a ...
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44 views

Designing a PID Controller for Satellite Control

As an Aerospace Engineering Student, I have been trying to make a project of a PID Controller to control the attitude response of a satellite using the parameters from a project called Kufasat. The ...
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1answer
59 views

Do variables dimensions matter in PID simulation + I want the PID output to be volts?

I have a self balancing robot control loop that uses the PID controller. I feed the robot's angle (rad) to sum block that generates the error between the set point and the angle. The error then goes ...
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16 views

If a system is globally asymptotically stable AND locally exponentially stable, can we say claim that it is globally exponentially stable?

I am taking a nonlinear control class. As we were discussing stability, we came across 'weaker' and 'stronger' stability conditions. For example asymptotic stability (AS) is stronger than stability in ...
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27 views

Control systems to control position of antenna with motor?

I want to design a control system with microcontroller to control position or orientation of antenna with BLDC motor with high precision like 0.1 deg and I don't have idea which motor position ...
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21 views

Observable Canonical Form - Modern Control

I have derived controllable canonical form (very easily), but I have trouble deriving observable canonical form (supposed to be easy.. at least every textbook is implying so). The picture underneath ...
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31 views

How to use lsim in matlab for a closed loop system

I have designed a system using a minimum realization. I have the A, B, C matrices and I have assigned closed loop poles for the system. I used the place command to find my K matrix. I am wondering ...
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9 views

Controls system response to step functions and impulse functions

when a impulse or step function are applied to a system, is the impulse function like being on a physical system and the step response like applying a constant force to something like a mass spring ...
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36 views

Derive a Transfer Function from first principles (PID, system identification, statics)

I want to derive a transfer function of my system so I can plug it into MATLAB and use the PID tuner tool. My system is a balancing beam with a motor on each end of the beam. My first principles ...
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31 views

How to tune PID for a step response

I am very much confused finding the time constant and DC gain for the below step response. The idea is to find PI gains for speed control and I am following this tutorial online Tutorial Link Motor ...
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19 views

Significance of asymptotes in root locus

What is the significance of asymptotes in the root locus of a linear time invariant system. Does it say that for that particular pole on which it is starting doesn't have a practical pole in the ...
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20 views

Criterion to neglect poles of higher order

If I am having a fifth order system, it is said that the dominant two poles nearer to the jw axis determine the nature of the output, is there any criterion to neglect the other three poles , should ...
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27 views

Why does a lead-compensator type system decrease to a step response

For example, the step response of $\frac{s+1}{s+2}$ is decreasing although its gain is +1, and this system has higher gain at high frequencies than low frequencies based on its Bode plot. But if I ...
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29 views

Output matrix for system with accelerometer

Consider a generic second order state space SISO system \begin{equation} \left[ \begin{array}{c}{\dot{\tilde{x}}_{1}} \\ {\dot{x}_{2}}\end{array}\right]=A \left[ \begin{array}{c}{\tilde{x}_{1}} \\ {\...
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29 views

How can I tune the parameters of a lqr controller?

From my internet research, it seems there's no systematic way of tuning the design parameters for the LQR controller. I have found Bryson’s rule as an initialization. However I don't know how to ...
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54 views

What is the appropriate type of controller for this system?

I am given this transfer function for a system: $T\left(s\right)=\frac{9.81}{s^4+0.5s^3+11.2815s^2+4.905s}$ Now, I want to design a controller that will make the closed loop system have an overshoot ...
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38 views

Digital control implementation in MCU

I have implemented a PI compensator for an integrator plant through floating point variables and everything works fine. The design intent is tracking filter and it does not track well the input signal....
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42 views

Control law for nadir pointing spacecraft

Hoping someone here can give me some advice. I've been trying to build an orbit and attitude propagator inside MatLAB and have run into some issues with the attitude propagation due to my lack of ...
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20 views

How can I damp oscillating behaviour caused by quantization in a digital control system?

After introducing a quantization block in the simulink model, the output of the controlled system starts to oscillate around the zero fixpoint. I am using a lqr controller to regulate the system, ...
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29 views

How to design a transfer function for a Model Rocket?

I am building a roll stabilized model rocket. I am beginner at controls systems. How do I find out the transfer function of the rocket. Although, I am aware of definitions and stuff of control systems....
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53 views

Discrete PID controller

I need the equation of a discrete PID controller and I find different answers from different websites. For example, here the answer is: $$u[k] = u[k-1] + (K_p + K_i \frac{T_s}{2} + \frac{K_d}{T_s}) e[...
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26 views

Power generation in combustion engine

Here's the problem: On the one end of low-speed engine (driving end) I can measure the torque transformed to mechanical energy. On the other end (free end) I'd like to join power generator with a ...
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1answer
61 views

Strange simulink error. Professor & TA don't know. Any Ideas?

I am currently working on developing a simulation for a restricted UAV, and I’m having some issues with Simulink while doing this. I have my mathematical equations which have been approved by my ...
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91 views

PID control of a DC motor with PWM from Raspberry Pi - how to cross dead area?

I'm driving a DC motor (actually a linear actuator) with a Polulu motor controller from a Raspberry Pi. The motor drives if you ask for anything between 20 and 100% duty cycle, so there is a dead zone ...
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28 views

Name of protocol used to communicate with Fuelling Station Dispensors

I am trying to figure out the actual (Range of ) communication protocols used to communicate with Fuel Dispensers at fuel retail outlets. I see them write 2-wire protocol which is not specific as ...
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34 views

Defining transfer functions in MATLAB properly

So for a robust control problem I had to use a weighting function of the form: $$ W_P=\frac{0.5s+0.05}{s} $$ And I do so by ...
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36 views

Can one move the zeros of a transfer function?

This may be a very simple question and I think I know the answer but I would like it to be confirmed by somebody else. My questions regard the zeros of a systems (the roots of the numerator of a ...
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25 views

What motors to use to guide tape with high speed

My field isn't dealing with motors and such at all, however, I now need to build something that controls two motors. So I have two guiding reels with tape between them, similar to old tape recorders. ...
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Ideas needed: how to tilt a panel side to side [closed]

requirements: a panel of wood 4 ft long by 2 ft wide laying flat this panel should be able to tilt side to side (2 way) the weight on the panel will be about 250 lbs up to 400 lbs. controlled lift of ...
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95 views

Is the speed of a DC motor proportional to PWM?

I'm trying to control the speed of DC motor but unsure of the relationship between speed and PWM. I'm aware that the bigger the duty cycle, the larger the speed, but how exactly would this ...
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39 views

How can I model disturbances to a plant in the simulink model?

From multiple online tutorials, I have seen that disturbances to the plant are modeled as an addition of a disturbance signal to the input of the plant. Similar to the picture below : However, not ...
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Problem with transfer function in DC Motor

I'm trying to verify whether the transfer function in this control diagram is the one stated in this document. I tried solving it and got this: Shifting the armature current $$I_a$$ feedback point ...
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27 views

How to implement Pade Appromixation into State Space form

I have a State Space model and I need to create an Internal delay. Therefore I want to take a certain Padé approximation and convert it to ABCD matrices and extend my current model. However I do not ...
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27 views

Unbalance voltage mesurements from 63 kV power transformer

After testing a power transformer(pt) and closing its wiring terminals I've encountered that phase S 63 kV correct voltage and phases R and T shows incorrect voltage 32 kV. Can any body tell why?
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What is the actual difference between a control function with Securtiy Integritiy Level (SIL) II and one without?

Consider a simple example: there's a vessel with water and a continuos level sensor (4-20 mW signal) there's a water line with a magnetic valve, feeding the vessel When the water level is below a ...