3 ms·

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://

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...
arethuza 9y ago
I have known people working on control systems for large industrial plants (offshore in the North Sea) and they said they used basic undergraduate level control theory (PID etc.) but that the "control theory" part of any project was probably only a couple of percent of the total size of the project. Mind you that was a a few years back!
- wenc 9y ago
  This is true for the most part. The majority of loops out there are still PID. Most mechanical systems are fast, simple and linearizable, and PID is robust and simple to implement. The control law is simple. Advanced Control techniques like MPC are generally applied on complex plants such as chemical plants. In chemical plants, systems are slow but complex (highly multivariate with many interactions), so more complex optimal control techniques like MPC have a larger payoff. MPC has to solve an numerical optimization problem at every iteration, and requires more computational horsepower (not to mention prior mathematical modeling from step test data). But even in chemical plants, the local loops are PID (actually, PI... D is rarely used). The MPC layer optimizes an objective function and sends setpoints to local PI loops to carry out control.

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...

arethuza 9y ago

I have known people working on control systems for large industrial plants (offshore in the North Sea) and they said they used basic undergraduate level control theory (PID etc.) but that the "control theory" part of any project was probably only a couple of percent of the total size of the project. Mind you that was a a few years back!

wenc 9y ago
This is true for the most part. The majority of loops out there are still PID. Most mechanical systems are fast, simple and linearizable, and PID is robust and simple to implement. The control law is simple. Advanced Control techniques like MPC are generally applied on complex plants such as chemical plants. In chemical plants, systems are slow but complex (highly multivariate with many interactions), so more complex optimal control techniques like MPC have a larger payoff. MPC has to solve an numerical optimization problem at every iteration, and requires more computational horsepower (not to mention prior mathematical modeling from step test data). But even in chemical plants, the local loops are PID (actually, PI... D is rarely used). The MPC layer optimizes an objective function and sends setpoints to local PI loops to carry out control.