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Some Big Beautiful Treaded ATV Robots - Page 3 — Parallax Forums

Some Big Beautiful Treaded ATV Robots

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Comments

  • WhitWhit Posts: 4,191
    Great video Duane - you are as good a sales person as erco - High Praise!
  • ercoerco Posts: 20,256
    BTW my guess is that the bot drifts in balance mode because it lacks wheel encoders. Still impressive IMO and a nice surprise feature.
  • Duane, great video! Thanks for sharing.
  • erco wrote: »
    BTW my guess is that the bot drifts in balance mode because it lacks wheel encoders. Still impressive IMO and a nice surprise feature.

    I doubt its using encoders as well but doesn't it know it's drifting? The microcontroller is sending PWM signals to the motors so it knows it's not stopped, right?

    I haven't programmed a balancing bot myself but I'd think one could do a better job of keeping the bot stationary even without encoders.

    Another quirky behavior is the way the robot spins its wheels forward at the end of a jump. This forward spinning makes it very difficult to land with any precision. I was able to get the bot to jump up on a raised platform (just a couple inches off the floor) but I had to add some backward input to keep the bot from just driving off the raised platform.

    I'm still pleased with this purchase but I think the programming of the bot could have been improved a bit.

    My biggest gripe is the two separate joysticks for control. Using two joysticks is not nearly as intuitive as a single stick.

    I realized after posting the video, I just made my first "Unboxing" video. The box the bot jumped out of was the box it came in.

  • ercoerco Posts: 20,256
    Without encoders, it can't know absolute position to establish a set point. Same way a CR servo can't know position from cumulative drift.
  • Duane Degn wrote: »
    erco wrote: »

    I realized after posting the video, I just made my first "Unboxing" video. The box the bot jumped out of was the box it came in.
    Congrats on Unboxing video! :)
  • erco wrote: »
    Without encoders, it can't know absolute position to establish a set point. Same way a CR servo can't know position from cumulative drift.

    Yes, but it knows the motor is moving. It knows it's not receiving any input to move from the controller and it knows it's sending PWM signals to the motors so it knows it's moving when it's supposed to be still. I wouldn't think it would be too hard to modify the algorithm to detect when it's moving when it's not supposed to be moving. Of course this sort of stuff is always easier said than done. I may be wrong to assume this sort of drift wouldn't be hard to fix.

  • Publison wrote: »
    Congrats on Unboxing video! :)
    Publison wrote: »
    Duane, great video! Thanks for sharing.
    Whit wrote: »
    Great video Duane - you are as good a sales person as erco - High Praise!

    Thanks for the kind words guys.

    It seemed kind of odd to post a video about something I purchased rather than posting a video about a project.

    I purchased two of these bots. My intention was to modify one of the bots and have an unaltered bot for comparison. I think this bot will be hard to improve upon.

  • Duane Degn wrote: »
    It seemed kind of odd to post a video about something I purchased rather than posting a video about a project.

    It's a project, it just doesn't know it's a project yet! It's a pre-project video! :)
  • ercoerco Posts: 20,256
    edited 2016-06-15 18:11
    Duane Degn wrote: »
    Of course this sort of stuff is always easier said than done. I may be wrong to assume this sort of drift wouldn't be hard to fix.

    I too thought it would be a "simple" matter.



    This related video on the "Switchblade" bot popped up. Nice balancing while "transforming" & shifting CG.



  • mindrobotsmindrobots Posts: 6,506
    edited 2016-06-18 11:58
    Need tank parts?? I stumbled across this place - a lot of it you can find elsewhere but they do have lots of different tread and drive wheels and bogies and idlers and such that could be useful in building treaded vehicles - and it is all listed in once place. Some of their prices are just plain crazy but then the next listing is the same thing for a reasonable price.

    I haven't ordered anything from them (yet) so I can't vouch for quality or service.

    P.S. You're all welcome!! Just helping others spend their money.....
  • WhitWhit Posts: 4,191
    Great find mindrobots! Tons of interesting stuff and many items that I have never seen before!
  • Thanks, the only trick is to figure out if yu want the $1100 version of something or the $149 version!

    I was looking at it more as a place to go window shopping; "hmmm, those are neat, can I find them cheaper someplace?"
  • ercoerco Posts: 20,256
    Agreed, nice variety and it's big fun finding a new place for parts, even if just looking around. As elsewhere, you can get your appetite anywhere, as long as you go home for dinner. :)
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