5 ms·

Fortunately, basic PID analysis, including linear state-space representation and practical tuning methods (e.g. Ziegler-Nichols[1]), is taught in pretty much an

Fortunately, basic PID analysis, including linear state-space representation and practical tuning methods (e.g. Ziegler-Nichols[1]), is taught in pretty much any first EE control theory course at the undergraduate level. [1] https://en.wikipedia.org/wiki/Ziegler%E2%80%93Nichols_method https://en.wikipedia.org/wiki/Ziegler%E2%80%93Nichols_method

beambot 9y ago
Not only that... Classic controls (including PID, Routh-Hurwitz, root-locus, etc) are NOT taught in many graduate PhD controls programs!
- budadre75 9y ago
  Are those topics no longer relevant to today's state of the art research?
  - Sean1708 9y ago
    It's possible that you're just expected to know them at that point.
    - donquichotte 9y ago
      Agreed. Many state of the art control strategies nowadays are based on optimization techniques (e.g. Model Predictive Control, MPC, optimizes a convex cost function of the state, setpoint and input to your system over a certain time horizon). This has become a viable control strategy for fast (>1kHz) processes only in the past 15 years, since the optimization can be computationally intensive.
    - regularfry 9y ago
      Or be able to derive them. PID was never explicitly taught on my course, but all the theory behind it was.
  - tnecniv 9y ago
    Research? Largely no, although they crop up now and then in clever ways. They are still very relevant in industry, however.
- stealthcat 9y ago
  Those are undergrad courses. PhD should already know those by heart.
  - deleted 9y ago
    [deleted]
- TheArcane 9y ago
  Not even for Masters in control programs. It's state space all day!
  - wenc 9y ago
    State-space is less relevant to regulatory and servo control loops (which is the majority of loops out there), and more of interest in advanced control systems. Of course, in Masters programs, you are already expected to know basic PID control. Graduate courses that cover PID control tend to focus on intricacies like loop pairing, RGA, etc. PID control is an eminently practical field of study, and has many interesting facets like bump transfers, split range control, etc. There's a lot to learn about PID control that is non-theoretical.
dingo_bat 9y ago
Thanks, I was pretty confused for a moment.
peterburkimsher 9y ago
I took a class in PID and other control systems (PIP) in my 3rd year of undergraduate Electronic Systems Engineering at Lancaster University in the UK. http://www.research.lancs.ac.uk/portal/en/publications/-(65747ce1-274f-4a92-a60d-b41d3bb456f7).html http://www.research.lancs.ac.uk/portal/en/publications/-(657... I enjoyed the class and got good grades, but I've never had to use it in practice. Now I work for a tech company in Taiwan who make microSD cards, and some of the programming projects I worked on involved writing drivers for the testing machines. That was called "automation and control", but it's all been in software. I like hardware, but I really don't know how to get back into it after 7 years in software.
- snarfy 9y ago
  You need some hardware projects. Designing and building something like a 3d printer or cnc machine from scratch is quite rewarding. Here is a weekend project I did using 3 RC servos and an arduino: https://www.youtube.com/watch?v=cbNiJKSRCpA https://www.youtube.com/watch?v=cbNiJKSRCpA
  - throwawaybbqed 9y ago
    Cool project! I had always thought 3D printers needed steppers for more accuracy (as opposed to servos). Is it the 3 arm config of the 3d printer that makes lower accuracy servos work? Curious where you sourced the hw pieces?
    - snarfy 9y ago
      The RC servo project is definitely not accurate enough for printing. It was just a fun project. It would need gears or some other mechanism to get the resolution up there.
      - cr0sh 9y ago
        Most delta 3D printers use steppers and a linear rail of some sort to gain the required resolution (and height for volume), but I bet you could use BLDC motors in a similar control fashion as used in stabilization gimbals for cameras on hobby drones and similar. I'm not sure if it would be better resolution than micro or continuous "stepping" or not...
godelmachine 9y ago
I never had Ziegler-Nichols as part of my Control Systems syllabus. My univ referred Bakshi & Bakshi as primary text book. Google Books link → https://books.google.co.in/books/about/Control_Systems.html?id=D3vFPzbBRPUC https://books.google.co.in/books/about/Control_Systems.html?...
- metaphor 9y ago
  The method is simple and practical enough that--if anything--it would have been covered as part of supplemental lab supervised by a graduate TA after professor lays foundation for PID control in lecture the week prior.
  - deleted 9y ago
    [deleted]
airbreather 9y ago
From my experience in O+G and mining processing plant control systems many people that tune loops regularly for a while can basically do it by inspection, with small adjustments after the first pass. First rule is you will not need any derivative except in a handful of particular cases that are well known/identifiable.

beambot 9y ago

Not only that... Classic controls (including PID, Routh-Hurwitz, root-locus, etc) are NOT taught in many graduate PhD controls programs!

budadre75 9y ago
Are those topics no longer relevant to today's state of the art research?
- Sean1708 9y ago
  It's possible that you're just expected to know them at that point.
  - donquichotte 9y ago
    Agreed. Many state of the art control strategies nowadays are based on optimization techniques (e.g. Model Predictive Control, MPC, optimizes a convex cost function of the state, setpoint and input to your system over a certain time horizon). This has become a viable control strategy for fast (>1kHz) processes only in the past 15 years, since the optimization can be computationally intensive.
  - regularfry 9y ago
    Or be able to derive them. PID was never explicitly taught on my course, but all the theory behind it was.
- tnecniv 9y ago
  Research? Largely no, although they crop up now and then in clever ways. They are still very relevant in industry, however.
stealthcat 9y ago
Those are undergrad courses. PhD should already know those by heart.
- deleted 9y ago
  [deleted]
TheArcane 9y ago
Not even for Masters in control programs. It's state space all day!
- wenc 9y ago
  State-space is less relevant to regulatory and servo control loops (which is the majority of loops out there), and more of interest in advanced control systems. Of course, in Masters programs, you are already expected to know basic PID control. Graduate courses that cover PID control tend to focus on intricacies like loop pairing, RGA, etc. PID control is an eminently practical field of study, and has many interesting facets like bump transfers, split range control, etc. There's a lot to learn about PID control that is non-theoretical.

dingo_bat 9y ago

Thanks, I was pretty confused for a moment.

peterburkimsher 9y ago

I took a class in PID and other control systems (PIP) in my 3rd year of undergraduate Electronic Systems Engineering at Lancaster University in the UK. http://www.research.lancs.ac.uk/portal/en/publications/-(65747ce1-274f-4a92-a60d-b41d3bb456f7).html http://www.research.lancs.ac.uk/portal/en/publications/-(657... I enjoyed the class and got good grades, but I've never had to use it in practice. Now I work for a tech company in Taiwan who make microSD cards, and some of the programming projects I worked on involved writing drivers for the testing machines. That was called "automation and control", but it's all been in software. I like hardware, but I really don't know how to get back into it after 7 years in software.

snarfy 9y ago
You need some hardware projects. Designing and building something like a 3d printer or cnc machine from scratch is quite rewarding. Here is a weekend project I did using 3 RC servos and an arduino: https://www.youtube.com/watch?v=cbNiJKSRCpA https://www.youtube.com/watch?v=cbNiJKSRCpA
- throwawaybbqed 9y ago
  Cool project! I had always thought 3D printers needed steppers for more accuracy (as opposed to servos). Is it the 3 arm config of the 3d printer that makes lower accuracy servos work? Curious where you sourced the hw pieces?
  - snarfy 9y ago
    The RC servo project is definitely not accurate enough for printing. It was just a fun project. It would need gears or some other mechanism to get the resolution up there.
    - cr0sh 9y ago
      Most delta 3D printers use steppers and a linear rail of some sort to gain the required resolution (and height for volume), but I bet you could use BLDC motors in a similar control fashion as used in stabilization gimbals for cameras on hobby drones and similar. I'm not sure if it would be better resolution than micro or continuous "stepping" or not...

godelmachine 9y ago

I never had Ziegler-Nichols as part of my Control Systems syllabus. My univ referred Bakshi & Bakshi as primary text book. Google Books link → https://books.google.co.in/books/about/Control_Systems.html?id=D3vFPzbBRPUC https://books.google.co.in/books/about/Control_Systems.html?...

metaphor 9y ago
The method is simple and practical enough that--if anything--it would have been covered as part of supplemental lab supervised by a graduate TA after professor lays foundation for PID control in lecture the week prior.
- deleted 9y ago
  [deleted]

airbreather 9y ago

From my experience in O+G and mining processing plant control systems many people that tune loops regularly for a while can basically do it by inspection, with small adjustments after the first pass. First rule is you will not need any derivative except in a handful of particular cases that are well known/identifiable.