Moderating Acceleration / Deceleration

[EricS-Team180]

Hi Tom, It's a be-deviling problem, isn't it

Here's a thread with a plot (from last year) that may shed some light on what you are dealing with:

pwm / voltage dat

and just a day or 2 ago, I saw a plot of a team's wheel speeds vs joystick input that is also good data....but I'll be darned if I can find it again

Anyway, you might try something like a rate limiter. We've done this in the past, but just ended up in an argument among team members on robot handling qualities. You can also search on something like "exponential drivetrain" to see how some teams re-map the joystick to motor relationship.

Here's a shot at some rate limit code that shows the general idea ... it ain't tested, so caveat cursor

//
// a joy stick rate limiter
//
unsigned char RateLImitJoyStick(unsigned char* joy,   // current joystick
                                unsigned char* LPjoy,           // LastPass joystick
                                int            RateLimit)            // rate of change limit
{
   int speed ;
   unsigned char limited = 0;

   speed = (int)*joy - (int)*LPjoy ;
   if(speed > RateLimit)
   {
       speed = RateLImit;
       *joy = speed + (int)*LPjoy ;
       limited = 1 ;
   }
   else if(speed < -RateLImit)
   {
       speed = -RateLImit;
       *joy = speed + (int)*LPjoy ;
       limited = 1 ;
   }
   else{} 
   *LPjoy = *joy
   return(limited) ;
}

I'm sure there are others on this forum that can improve on these ideas.

Good Luck!
(not quite in panic mode)Eric


PS the fighting pi's is a great name! Ha!