Erco's Figure Eight Challenge

13468922

Comments

  • TtailspinTtailspin Posts: 1,326
    edited December 2012 Vote Up0Vote Down
    Excellent work Gareth, It's harder than it looks...:smile:

    -Tommy
  • Martin_HMartin_H Posts: 4,037
    edited December 2012 Vote Up0Vote Down
    I like the light trails. Going with a 2 mm clearance is hard mode, so clipping the bottle isn't that usual.

    Now let's see an orbit challenge video! That goes for you too Tommy!
  • Duane DegnDuane Degn Posts: 10,002
    edited December 2012 Vote Up0Vote Down
    Here's my first attempt at having my hexapod walk in a figure 8.

    I was using a cheap video camera from HobbyKing. Its microphone is really wimpy.

    I just rewatched this video. The sound seems to loose sync with the video towards the end.
  • mindrobotsmindrobots Posts: 6,497
    edited December 2012 Vote Up0Vote Down
    Brilliant for a first attempt!!

    It's always just good fun and a little creepy to watch those guys walk around.

    jqspider.jpg


    Obviously too much Johnny Quest as a kid!!
    261 x 193 - 10K
    MOV OUTA, PEACE <div>Rick </div><div>"I've stopped using programming languages with Garbage Collection, they keep deleting my source code!!"</div>
  • ercoerco Posts: 19,268
    edited December 2012 Vote Up0Vote Down
    Love it. Now make it walk around two Christmas tree ornaments (kicking them like soccer balls is a plus) and enter it into the HTH contest!
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Martin_HMartin_H Posts: 4,037
    edited December 2012 Vote Up0Vote Down
    Nicely done. That's a good example of how eighteen servos allows for holomonic motion.
  • max72max72 Posts: 1,134
    edited January 2013 Vote Up0Vote Down
    A little late to the party, but here is my take.
    The robot is made of Al parts and rivets, and 3D printed wheels. The motors are the cheap steppers. Sorry, no plywood.
    I remotely programmed it with the Wifly module and Tachyon Forth.
    From the terminal to start an eight figure I enter:
    2ndcircleradius 1stcircleradius eight
    in this case I typed:
    250 375 eight
    
    Attached is also the code. The constant to be set are in the first part.
  • Martin_HMartin_H Posts: 4,037
    edited January 2013 Vote Up0Vote Down
    It's never too late and great job. Now why not try the Ultrasonic Orbit challenge http://forums.parallax.com/showthread.php/144539-Erco-s-Ultrasonic-Orbit-Challenge

    Any other takers?
  • mindrobotsmindrobots Posts: 6,497
    edited January 2013 Vote Up0Vote Down
    YAY!!!!! A robot running a Forth derivative that nails the figure 8!!

    Well done!!!
    MOV OUTA, PEACE <div>Rick </div><div>"I've stopped using programming languages with Garbage Collection, they keep deleting my source code!!"</div>
  • TtailspinTtailspin Posts: 1,326
    edited January 2013 Vote Up0Vote Down
    Plastic traffic cones? where is the danger in that?... Just kidding, :)

    Great work Max72, :thumb:


    -Tommy
  • ercoerco Posts: 19,268
    edited January 2013 Vote Up0Vote Down
    Fabulous job, max72! The FIRST FORTH robot in the challenge.

    That's even better than the Fifth Third bank in Michigan. https://www.53.com/site/about
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • ercoerco Posts: 19,268
    edited January 2013 Vote Up0Vote Down
    Martin_H wrote: »
    It's never too late and great job. Now why not try the Ultrasonic Orbit challenge http://forums.parallax.com/showthread.php/144539-Erco-s-Ultrasonic-Orbit-Challenge

    Any other takers?

    Soon come, my Christmas tree video was not my entry.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • max72max72 Posts: 1,134
    edited January 2013 Vote Up0Vote Down
    Thanks. Great fun indeed. I had fun both building the bot and writing the code.. I started with a fully 3D printed project, but rivets are so easy to use..
    Both the orbit challenge and the ellipse challenge are extremely intriguing.... :-)

    Massimo
  • Duane DegnDuane Degn Posts: 10,002
    edited January 2013 Vote Up0Vote Down
    max72 wrote: »
    here is my take.

    It's great to see a Forth robot.

    Thanks for posting the video.
  • ercoerco Posts: 19,268
    edited January 2013 Vote Up0Vote Down
    Just one walking robot, my main man Duane's hexapod in post #154?

    No bipeds? Aren't there a lot of Penguins out there? Where's Doggiedoc's Toddler?

    Not even a Boebot crawler?

    Hmmm. That proves that Duane is better than all the rest of us put together!
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Duane DegnDuane Degn Posts: 10,002
    edited October 2015 Vote Up0Vote Down
    This is my attempt at making an inexpensive robot.



    The chassis is made from foam board. You may notice there isn't a caster wheel. It's just a piece of foam board that drags along the ground to keep the robot upright. It was really easy to build it mostly held together with double sided foam tape. No glue was used on this robot.

    I'll likely redo the wheels with some peanut butter lids once I finish eating our two jars of peanut butter (I'm slightly allergic so I can only eat about 1/4 of a jar a day). The current Lego wheels are out of place with this cheap bot. I like the Lego wheels but I want to keep the BOM for this bot as low as I practically can.
  • lardomlardom Posts: 1,495
    edited February 2013 Vote Up0Vote Down
    @Duane Degn, How do you power your QuickStart? I thought it had to be tethered to the computer.
    Larry

    If the grass is greener on the other side...it's time to water your lawn.
  • ercoerco Posts: 19,268
    edited February 2013 Vote Up0Vote Down
    I said it before and I'll say it again: This proves that Duane is better than all the rest of us put together!
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Duane DegnDuane Degn Posts: 10,002
    edited February 2013 Vote Up0Vote Down
    lardom wrote: »
    @Duane Degn, How do you power your QuickStart? I thought it had to be tethered to the computer.

    Larry,

    Pins 39 (ground) and 40 (Vin) can be used power the QuickStart board.

    I found a picture here showing how I connect a battery pack to the QuickStart. When I use NiMH batteries, I plug the battery pack (with four AA cells) directly into the QuickStart board without a regulator in between. I don't recall the voltage the QuickStart board can tolerate on its Vin pin but I'm sure it's more than the 5.4V of the freshly charged NiMH cells.

    I was having too much trouble with voltage changes from discharging NiMH cells to continue using the raw voltage from the battery pack. In order to keep the speed of the servo consistant, I added a voltage regulator to keep the Vin a constant 5.0V. Once I started using the voltage regulator, I also used Li-Ion cells in the battery pack. This combination kept the servo speeds consistant from one run to the next.
    erco wrote: »
    I said it before and I'll say it again: This proves that Duane is better than all the rest of us put together!

    erco, It's your fault my head is so big I can no longer find hats that fit!



    I plan to start a thread tomorrow to post some more details about my cheap bot.
  • lardomlardom Posts: 1,495
    edited February 2013 Vote Up0Vote Down
    @Duane Degn, Thanks. I'm going to start doing that. It will really speed things up. It will make my stuff look much less crappy.
    IMG_3435_2.jpg
    1024 x 768 - 94K
    Larry

    If the grass is greener on the other side...it's time to water your lawn.
  • Duane DegnDuane Degn Posts: 10,002
    edited February 2013 Vote Up0Vote Down
    lardom wrote: »
    @Duane Degn, Thanks. I'm going to start doing that. It will really speed things up. It will make my stuff look much less crappy.
    IMG_3435_2.jpg

    I only see beauty in that robot!

    I see you're also using a "tail dragger".

    I'm hoping you'll make a video so we can see that beauty in motion.
  • lardomlardom Posts: 1,495
    edited February 2013 Vote Up0Vote Down
    :smile: It's actually an RC airplane wheel that I got from the local hobby store. I have a mecanum wheel, one of many ideas I've picked up from erco. The project I'm working on is mostly for fun and knowledge so I probably won't spend a lot on its appearance.
    Larry

    If the grass is greener on the other side...it's time to water your lawn.
  • lardomlardom Posts: 1,495
    edited February 2013 Vote Up0Vote Down
    Duane, can you recommend a supplier for the headers?
    I'm hoping you'll make a video so we can see that beauty in motion.
    I did post a YouTube video a few days ago because I learned to control my steppers differentially meaning I could program it numerically to move in an arc. That video will have to show some life without my help or I'll replace it with something worth watching.
    Larry

    If the grass is greener on the other side...it's time to water your lawn.
  • Duane DegnDuane Degn Posts: 10,002
    edited February 2013 Vote Up0Vote Down
    lardom wrote: »
    Duane, can you recommend a supplier for the headers?

    I made a bill of material for the robot here.

    I think the two by four female header was cut from a section I purchased from Digi-Key. Two single row headers works just as well (and sometimes better) as using double row headers.
  • ercoerco Posts: 19,268
    edited February 2013 Vote Up0Vote Down
    My mecanum bot does a sideways 8:
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Duane DegnDuane Degn Posts: 10,002
    edited April 2017 Vote Up0Vote Down
    Many of my robots are rebelling and wouldn't perform a figure 8 for me. I had to revert to using an old friend in order to get my latest figure 8 fix.



    I'm hoping I can quell this latest uprising and get some more of my robots to perform here.
  • ercoerco Posts: 19,268
    edited February 2013 Vote Up0Vote Down
    BRAVO! That was two beautiful circles! I can almost see the sins & cosines flowing past. Now I love your mecanum video, too, but that was clearly two octagons... the EASY way out. These circles are impressively smooth.

    I'm picky in my old age. It takes a discriminating eye to pick up on these subtleties, but I know there's a heck of a lot of code and testing required to get a nice smooth run like that. Encoders, right?

    Next, my man, I'd like to see your bot rotate on axis as it traces out a figure path...! :)

    W9GFO and Kepler are long overdue for this!
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Duane DegnDuane Degn Posts: 10,002
    edited February 2013 Vote Up0Vote Down
    erco wrote: »
    BRAVO! That was two beautiful circles! I can almost see the sins & cosines flowing past. Now I love your mecanum video, too, but that was clearly two octagons... the EASY way out. These circles are impressively smooth.

    Unfortunately the Mecanum is one of the robots in rebellion. I agree the Mecanum made two octagons. I had a bug in the program that converted the floats to integers too early and the rounding error turned into a squaring error (as in flattened circles not a number multiplied by itself). I've since fixed the bug but I haven't made a new video of it in action.

    The omni bot code was pretty simple. I just set the speed to two thirds it's maximum and incremented the direction (by 1/200 of a circle) 200 times per loop of the "8". It could be improved by taking into account the start and stop times.
    erco wrote: »
    I'm picky in my old age. It takes a discriminating eye to pick up on these subtleties, but I know there's a heck of a lot of code and testing required to get a nice smooth run like that. Encoders, right?

    Not in this one. Just those expensive Dynamixel AX-12+ servos. Not the most practical application for the servos but they sure make nice motors.

    The only testing consisted of figuring out where to put the pie tins so the robot wouldn't hit them. The code pretty made the figure 8 a guarantee. I got lucky it was about the right size. You're right about the sines and cosines; there's a bit of trig involved to get the motors to run at the correct speeds.
    erco wrote: »

    Next, my man, I'd like to see your bot rotate on axis as it traces out a figure path...! :)

    Why am I not surprised? This is on my (very long) todo list.
    erco wrote: »

    W9GFO and Kepler are long overdue for this!

    Agreed.

    I also think Jeff owes us an OBC CheapBot figure 8.
  • ercoerco Posts: 19,268
    edited February 2013 Vote Up0Vote Down
    Duane Degn wrote: »
    Just those expensive Dynamixel AX-12+ servos. Not the most practical application for the servos but they sure make nice motors.

    OK, that demystifies it a bit. Those have velocity feedback and all kind of onboard help (nearly encoders!). I'm still impressed.

    You saw my fake mecanum 8 a few posts ago. Those are just DC motors and L298 controllers. I plan to do an 8 with real circles there, too, more like your octagon. But also without encoders. I have to do some testing and map out wheels RPM to PWM input. It's nowhere close to a linear relationship.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Duane DegnDuane Degn Posts: 10,002
    edited February 2013 Vote Up0Vote Down
    erco wrote: »
    OK, that demystifies it a bit. Those have velocity feedback and all kind of onboard help (nearly encoders!). I'm still impressed.

    Yeah, as I keep trying to tell you, if you have good hardware the software is easy. :innocent:
    erco wrote: »
    You saw my fake mecanum 8 a few posts ago. Those are just DC motors and L298 controllers. I plan to do an 8 with real circles there, too, more like your octagon. But also without encoders. I have to do some testing and map out wheels RPM to PWM input. It's nowhere close to a linear relationship.

    Good luck. Not only is the relationship between PWM and RPM not linear, it's not even a fixed relationship. The PWM to get to a certain RPM depends on the motors current speed as well as the target speed. Once the target speed is met, the PWM will need to be adjusted to keep from going even faster (or slower). It might be possible to tease out all these details but I doubt it will be easy.

    Edit: My comments about PWM and RPM are true for the relatively under powered Rover 5. The relationship might be better behaved with more powerful motors.
Sign In or Register to comment.