Help with Ramping Code for Boe-Bot

Comments

• Zoot Posts: 2,227

  2008-01-21 21:39 edited 2008-01-21 21:39

  Rather than a subroutine per se, you might think about just adding/subtracting a set value from the motor speed(s) each time through the loop. For example, on one of my Boe-bots, when the bot has to avoid using IR, rather than just setting turn speeds, I do something akin to this:
  
  

  IF irLeft = Detected THEN
     motorLeft = motorLeft + 5 MAX 255 ' in my case I map motor speeds of 0-128-255 to 650-750-850 pulsewidths;
     motoRight = motorRight MIN 5 - 5    ' it's  a convenience that saves var space, but is technically unneccesary
  ELSEIF irRight = Detected THEN
     motorLeft = motorLeft MIN 5 - 5
     motorRight = motorRight + 5 MAX 255
  ELSE ' straighten out but do it more quicky
     motorLeft = motorLeft + 10 MAX 255
     motorRight = motorRight + 10 MAX 255
  ENDIF
  
  

  
  
  
  The only trap here is if you are doing any kind of subsumption based program (like many of the examples for the Boe floating around the forum). Many of those routines effectively "destroy" the previously sent motor speed, so you need to either preserve the last "sent" speed, or you need to code your subsumption state machines so they do not destroy the previous motor speed if they are not actually subsuming.
  
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  1uffakind.com/robots/povBitMapBuilder.php
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• Felix79 Posts: 3

  2008-01-22 04:33 edited 2008-01-22 04:33

  Cool.. Thanks for the Reply there Zoot - but I'm not exactly sure what you are trying to tell me here.· Hmm, though I will try and see if I can put in values beside the PULSOUT 750 code bit... Maybe something like your post - PULSOUT 13, 750 + 5 MAX 100 for my Boe-Bot.· I'll re-post here again if I can figure something out.
• Felix79 Posts: 3

  2008-01-22 05:35 edited 2008-01-22 05:35

  Nope, that didnt work.. Hmm - starting to wonder if it is not possible for there to be any gradual acceleration of servo motors without giving them a set number of pulses to do ( FOR pulseCount = 1 TO 100 )...
  
  One other question.. Why is there not a Sticky Boe-Bot thread? Like for the ones Penguin robot and Squibbler Robot?
• Zoot Posts: 2,227

  2008-01-22 17:05 edited 2008-01-22 17:05

  It is absolutely possible. Sorry -- the code fragment I provided is probably not enough info for you.
  
  The basic idea is that you have a subroutine, or a single place in your code, where the motor speeds are actually "dumped" and output to the servos. That way you can have your main loop keep tweaking and changing the motor speeds, and when the loop is done, THEN the final "set" speeds are actually sent. This might show it better. I'm using Words for servo speeds for simplicity, but words are a real waste of var space for these speeds (if your servo speed range is 650-850 that's a range of only 200, far less than a byte):
  
  

  servoLeft PIN 12  ' change if necessary
  servoRight PIN 13 ' change if necessary
  motorLeft VAR Word ' left servo speed
  motorRight VAR Word ' right servo speed
  
  
  Main:
  
    
  Obstacle_Check:
  IF irLeft = Detected THEN
     motorLeft = motorLeft + 5 MAX 850 ' turn right gradually
     motorRight = motorRight - 5 MIN 650
  ELSEIF irRight = Detected THEN
     motorLeft = motorLeft - 5 MIN 650 ' turn left gradually
     motorRight = motorRight + 5 MAX 850
  ELSE ' straighten out but do it more quicky
     motorLeft = motorLeft + 10 MAX 850
     motorRight = motorRight + 10 MAX 850
  ENDIF
  
  Output_Servos:
    PULSOUT ServoLeft, 1500 - motorLeft ' note that the motorspeed vars are "normal" -- 850 is forward for both;
                                                          ' only during output is the "backwards" motor value switched around
    PULSOUT ServoRight, motorRight
    PAUSE 5 ' this pause may need to be adjusted up or down (or eliminated) depending on how long it takes to run through the whole loop
                  '  -- the goal is for all the code + the pause to add up to about 20ms
  
  Main_Loop_Done:
    GOTO Main
  
  

  
  ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
  When the going gets weird, the weird turn pro. -- HST
  
  1uffakind.com/robots/povBitMapBuilder.php
  1uffakind.com/robots/resistorLadder.php