PID Tuning For High power model rockets

[Hamid 'Smith' Salehi]

Hello friends, how professional model rocket designers adiust / tune the PID parameters of high power model rockets for their stability? I mean those who use an active stabilizer system with canards, because TVC cannot be used easily in high power model rockets, are they using a software for this?
OpenRocket does not support supersonic speeds, and these rockets fly at this speed, so it should not be a good option for this.
Any idea?

 

[user 30299]

Hello friends, how professional model rocket designers adiust / tune the PID parameters of high power model rockets for their stability? I mean those who use an active stabilizer system with canards, because TVC cannot be used easily in high power model rockets, are they using a software for this?
OpenRocket does not support supersonic speeds, and these rockets fly at this speed, so it should not be a good option for this.
Any idea?

Here is a link to a long-running thread by Jim Jarvis.

https://www.rocketryforum.com/threads/i-could-use-just-a-little-guidance.122042/page-29
Maybe this is the place to start and ask questions.

 

[jqavins]

Hello friends, how professional model rocket designers adiust / tune the PID parameters of high power model rockets for their stability? I mean those who use an active stabilizer system with canards...

Professional model rocket designers don't use active stabilization, to the best of my knowledge. Only crazy armatures (like some of us) do that, and only a few of them. From your question, it seems that you are preparing to join an elite group of extreme nut cases, and I mean that in a good way.

The following is absolutely not meant to discourage you.

Be aware that, strictly speaking, PID is an analog controls methodology that is often adapted for digital controls. In the broader range of digital control systems it's rather primitive, but attractive due to its relative simplicity. Also, I don't know first hand, but I'll just bet that many of those digital PID systems are not done exactly right, because the system performance that's modeled using a Laplace transform analog realm should use a Z transform in the digital realm, and I'm guessing that at least a good number of people implementing digital PID don't know that. Yes, I have the college classes in analog and digital control systems and digital signal processing (a control loop is, after all, just an application of signal processing). And what I've learned from those classes is that applying those techniques to drive canard actuators in order to steer a rocket is something I'm not going to attempt unless I want to spend a year or two on it and little or no other hobby activities.​

Go for it! Best of luck.

Here is a link to a long-running thread by Jim Jarvis.

https://www.rocketryforum.com/threads/i-could-use-just-a-little-guidance.122042/page-29
Maybe this is the place to start and ask questions.

@OverTheTop also has an extensively documented build of his Vertical Trajectory System, but I'm afraid I cant find it. Actually, he's got two of them; the one here is version two, and version one is documented on a different forum, and Australian one.