Camera for turning

[DustinB_3]

I have actually searched all over chiefdelphi for information. I found a lot except that I couldn't find anything about an output to control more than one pwm.

[Uberbots]

i actually have a bit of code that may help you.

PHP Code:

unsigned char PIkDControl(char Kp, char Ki, char Kd, int error) {
    static int errorTotal = 0;  //there is a better way to do this... meh
    static int prevError = 0;
    int P = 0;
    int I = 0;
    int D = 0;
    
    P = (error*Kp)/100;
    I = (errorTotal*Ki)/100;
    D = ((error - prevError)*Kd)/100;

    errorTotal += error;
    prevError = error;

    return  (Limit_Mix(2000+127+P+I-D));
} 


There are a couple of other tweaks, but i edited them out. you should come across them whilst testing (=

[DustinB_3]

Thanks, I'll try that. One question: What's the limit mix for. I have never seen it on a control loop.

[Uberbots]

limiting output, of course. you don't want your unsigned char to overflow, that would be bad

[DustinB_3]

While using your code how do i implement a target value and how do I out put it to four motors. Sorry for all the questions but PID loops are still very new to me.

[Uberbots]

the function is returning a motor value from 0-255. it is up to you to map it to your motors, like you would a joystick.

as for inputting the error... you need to figure out your error much like you did in your original loop. with the dual targets this year, though, you will have to do a little (lot) of extra math and AI to get your desired target.

[Tom Bottiglieri]

Originally Posted by DustinB_3

Sorry for all the questions but PID loops are still very new to me.

PID Without a Ph.D

All you had to do was ask...

[Alan Anderson]

Originally Posted by DustinB_3

...I couldn't find anything about an output to control more than one pwm.

A brief look at your existing code reveals that to be a non-issue. If you supply the same PID-computed value to all your motor pwms, your robot will turn in place. That's exactly what you want it to do, isn't it?