PID Controller

[Splatman]

Any chance of getting an Adv Dupe of the platform shown in the video near the start of the thread?

[siberx]

First, let me say this is a pretty nifty piece of hardware - I've been using homebrew discrete PD controllers for some time in gmod to stabilize a number of different contraptions, but found that the extra complexity of producing a full PID was rarely worth the effort and chips required to do it. This thing puts it in one small fast package, so hurrah for that.

While I've been able to tune the thing to converge and maintain a desired setpoint very easily, I've been running into problems when trying to smoothly adjust the setpoint of the system and have the PID track that change. I basically have a second circuit that allows me to alter the setpoint smoothly at a certain number of units per second, and invariably any time I attempt to change the setpoint the system will increasingly oscillate until I stop altering the setpoint, at which point the system converges almost immediately back to a stable value.

Perhaps the PID circuit is not well tuned to this and I should add a feed-forward to compensate for the setpoint shift, but anybody have any other suggestions that are simpler than this?

[tuusita]

While I've been able to tune the thing to converge and maintain a desired setpoint very easily, I've been running into problems when trying to smoothly adjust the setpoint of the system and have the PID track that change. I basically have a second circuit that allows me to alter the setpoint smoothly at a certain number of units per second, and invariably any time I attempt to change the setpoint the system will increasingly oscillate until I stop altering the setpoint, at which point the system converges almost immediately back to a stable value.

Perhaps the PID circuit is not well tuned to this and I should add a feed-forward to compensate for the setpoint shift, but anybody have any other suggestions that are simpler than this?

Having the same setpoint-oscillation problem. A solution or an upgraded PID would be nice.

[Azrael]

Excellent! Any thoughts about making an automatic tuner? The Ziegler-Nichols method is easy enough to implement if you can detect when it starts oscillating steadily.

[Kirk]

Oh man, you win.

I haven't played GMod in a while and when I got back to it I figured I'd update everything. Finding this is a treat. I've been using custom PID expression gates but this is just so much easier

[InfectiousFight]

Man, this sounds just like my Modified Delta Equation (delta equation, accumulation output instead of absolute). Good to see this functionality spread more, it's incredibly useful.

[Bobsymalone]

Man, this sounds just like my Modified Delta Equation (delta equation, accumulation output instead of absolute). Good to see this functionality spread more, it's incredibly useful.

I use your equation all the time since I read your thread about that plane, it's awesome. I'm sure PID controllers are too, but they're kind of big. I prefer everything to be done by a small minichip.

[Fizyk]

Ok, despite my poor Lua skills I was able to eliminate the bug which caused the PID controller to go crazy when SetPoint was changing. I also added multiplying the I part by dt - it should make it possible to use I gain values higher than 0.001

In the attachment - modified init.lua file.

[Qjet]

super delta? :O

[ame="http://ca.youtube.com/watch?v=FHFzUVdLyMA"]YouTube - Delta in WireMod[/ame]

Sorry for bringing this up It's just I find it relevant <.X

[ahref]

old stuff is old. PID is much more cooler. if you can stand the tweaking. 30 mins and my stuff still just spazzes out. but i get the concept.

so in short PID is much better L