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How to make boe-bot roll faster — Parallax Forums

How to make boe-bot roll faster

TBPTBP Posts: 1
edited 2010-10-27 04:07 in Robotics
I am new to the boe-bot and have entered a little contest that places some emphasis on roll speed. Are there any tips for help the Boe-bot roll faster? I can only get about 0.5 fps on new batteries using a for loop to command the pulsout. Thanks for any help.

TBP

Comments

  • W9GFOW9GFO Posts: 4,010
    edited 2010-10-25 20:52
    The simplest way is to increase the voltage to the servos. A Boe-Boost is an easy way to do that.

    30078-M.jpg

    Be sure to have the jumper that is near the servo ports set so that the servos draw power from VIN. Note that voltages over 6.0 volts will probably decrease the life of the servos.

    You could also swap out the servos for faster ones. They would need to be modified for continuous rotation.

    Rich H
  • iDaveiDave Posts: 252
    edited 2010-10-25 21:19
    Bigger wheels. The larger the diameter means more distance is covered per revolution.
  • HumanoidoHumanoido Posts: 5,770
    edited 2010-10-25 23:24
    In the code, use ramping to start and prevent wheels from slipping. It could create an edge to get up to speed faster, depending on the running surface. If executed properly, it may be enough to win.

    p138
    Robotics
    v2.2

    The key to ramping is to use variables along with constants for the PULSOUT command’s Duration argument. Figure 4-4 shows a FOR…NEXT loop that can ramp the Boe-Bot’s speed from full stop to full speed ahead. Each time the FOR…NEXT loop repeats itself, the pulseCount variable increases by 1. The first time through, pulseCount is 1, so it’s like using the commands PULSOUT 13, 751 and PULSOUT 12, 749. The second time through the loop, the value of pulseCount is 2, so it’s like using the commands PULSOUT 13, 752 and PULSOUT 12, 748. As the value of the pulseCount variable increases, so does the speed of the servos. By the hundredth time through the loop, the pulseCount variable is 100, so it’s like using the commands PULSOUT 13, 850 and PULSOUT 12,650, which is full-speed ahead for the Boe-Bot.
  • HumanoidoHumanoido Posts: 5,770
    edited 2010-10-27 04:07
    Another tip for going faster is to examine the locomotion of a Weevil Beetle from the Curculionoidea superfamily. They are less than 6mm in size and their movements are of particular interest. They show coarse movements at high speed in a way that is readily mimicked by servo motors. If the number of steps between two points A to B is reduced, a positioning motor can be rapidly advanced. I have used this technique with standard servos by increasing steps for developing Slo Mo for Penguin robots and it works to the converse at high speed.
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