PID or auto correcting turn system help

[arete1776]

Hi, this is my first year in vex robotics and I am new to any coding besides blocks. I know the basics of c++ and not much more.

As I’ve constructed a skills autonomous this season, I’ve noticed that my program is extremely inconsistent no matter what I do to the code. It can be so inconsistent that it almost scores different goals during different runs with the same exact code (even though all I do is change the battery and let the motors rest).

Anyway, I have been looking into creating a PID or some sort of auto-correcting turn system to make my runs more accurate. I have tried to find resources to help me with starting, but most teams keep their code to themselves so there isn’t a lot of examples or tutorials out there. If you could help me find resources, give me tips, or even show me an example program, that would be extremely helpful.

Thanks!

Edit: I would like to use the inertial sensor and c++ coding if possible.

[xTigr]

Here is a document by George Gillard that goes over the basics of a PID control loop with pseudocode
http://georgegillard.com/documents/2-introduction-to-pid-controllers

And here is an example P loop in vexcode c++

How to write code to accelerate and decelerate drive train code for autonomous

It’s probably best to make a separate function for the PID that you can call whenever you want. This way you can just pass the targetPos as a parameter to the function. void drivePID(double targetPos){ //this is a constant that you will need to tune double kP = 0.1; //error is just the difference between target and current pos //here I am just getting it from the front left motor, but it doesn't really matter which one you use double error = targetPos - FrontLeft.position(deg); //…

[arete1776]

Thank you! I’ll take a look at it.

[Connor]

Here is how you do forward/backward and turn PID:

VEXCode PID Tutorial

I will be allocating this thread to answering any questions in regards to the tutorial [C++ VEXCode V5 Text Tutorials - Autonomous PID and Multitasking] Fair Warning: I am unsure if I have the positive and negative motor values correct, as this is all done on the top of my head. So If the robot is continuing to go even after the lateral position is reached, change error = averagePosition - desiredValue; to error = desiredValue - averagePosition; If the robot continues to go even a…

for your turning, replace the variable from rightencoder-leftencoder to the inertial sensor heading