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Tank Tracks

ajwardajward Posts: 1,129
edited 2011-12-11 16:10 in Robotics
Hey All...

I've started tinkering with Ted again and I'm looking at upgrading from the Tamiya molded tracks.
Kind of narrowed my options to two sources:
1. Vex Track - Comes with the sprockets and idler wheels, but it looks kind of flimsy... to me anyhow.
2. Lynxmotion Track. Sturdy looking, but sprockets are sold separate.

Has anyone had experience with either of these? Or is there something out there comparable?

Thanks for any advice!

Amanda
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Comments

  • Tom CTom C Posts: 461
    edited 2011-10-19 10:30
    Amanda,
    You might want to search on Mattracks. I have three sets and have used one pair on a BoeBot in place of the wheels.
    Regards,
    TCIII
  • Martin_HMartin_H Posts: 4,051
    edited 2011-10-19 11:48
    Amanda, what's the goal of the upgrade? What kind of surface do you want to run the new tracks on?

    Another option are the Johnny Robot tracks which are hard plastic and unlike the Tamiya tracks they won't bind on surfaces like carpet. You can also buy sprockets for them that have servo splines built in. Solarbotics, Pololu, and Robot Shop sell them. The yellow drum machine robot uses them if you want to see a video of them in action.

    They also come in colors other than yellow.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-10-19 12:56
    Amanda,

    I have one of these Rover 5 robots. The jury is still out on if it's a good bot or not. I had the wheels too close together so the treads kept coming off. I plan on trying again with the wheels father apart. My Rover 5 is still in pieces from upgrading the encoder disks from 8 divisions to 24.

    The thing I do like about the Rover 5 is it comes with four motors (each with an encoder). It seems like a good deal for the price (if I can keep the treads on it).

    I also like the Lynxmotion Track. They look like they could be actually used outside in the real world. I've considered buying some several times. The price has kept from following through with them. I think I will eventually purchase a set with the needed motors and sprockets.

    There's something cool about robots with treads.

    Duane
  • ajwardajward Posts: 1,129
    edited 2011-10-19 14:21
    Tom C wrote: »
    Amanda,
    You might want to search on Mattracks. I have three sets and have used one pair on a BoeBot in place of the wheels.
    Regards,
    TCIII

    Hi Tom... I looked at their website and it looks as tho' they only have huge tracks. Can you post a photo of your application?
  • Tom CTom C Posts: 461
    edited 2011-10-19 17:37
    Amanda,
    You need to search for the Mattracks for model trucks/cars. Radio Shack used to carry a Mattrack equipped truck at Christmas.
    Do a search on eBay for Mattracks and model size tracks usually come up with the full sized ones.
    My Mattrack equipped BoeBot is packed away in the garage, but I will see if I can get the wife to shoot a picture of it this weekend.
    Regards,
    TCIII
  • BamseBamse Posts: 561
    edited 2011-10-20 11:27
    Love the yellow drum machine... ;-)
  • ajwardajward Posts: 1,129
    edited 2011-10-20 15:20
    Hey Y'all...

    @Tom C... I did find the Mattracks on eBay and the price was decent. They're cool, but not quite the layout I was looking for. The yellow drum machine is pretty cool!! (He does have an off switch, right? :-> )

    @Martin_H... The goal is... To be "Better than he was before. Better...stronger...faster." Oh wait, that was The Six-Million Dollar Man! ;-) But... that's kind of the idea tho.

    Where we're headed now...
    Just ordered the Lynxmotion 2 inch tracks, 2.75 inch sprockets and 6mm hubs. That will give me a "wheelbase" of about 7 inches... just about what we have now. (A tad over $113 with free shipping)
    Power will come from a pair of recycled Parallax 7.2V motors. With the 6 tooth sprockets, I figure a top speed of roughly 3 - 3.5 fps.

    Initially, he's just going to be a house 'bot. Perhaps outdoors later on, but no off-roading planned. ;-)

    Amanda
  • LaserLinesLaserLines Posts: 14
    edited 2011-10-20 15:48
    I thought this was kinda kewl... if you have more time than $ http://rctankcombat/articles/track-systems/ maybe someday...
  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-10-20 16:28
    LaserLines wrote: »
    I thought this was kinda kewl... if you have more time than $ http://rctankcombat/articles/track-systems/ maybe someday...

    Here's a working link.
    http://rctankcombat.com/articles/track-systems/

    @Amanda,

    I'm very interested in what you think of the Lynxmotion track. I how you keep us updated on your progress.

    Duane
  • graffixgraffix Posts: 389
    edited 2011-10-20 17:35
    This is my favorite rc tank.
    http://www.youtube.com/watch?v=XwizLJV5kl8
    http://www.youtube.com/watch?v=2dq8XQHVNAI
  • ajwardajward Posts: 1,129
    edited 2011-10-28 14:48
    We haz trax!

    The parts from Lynxmotion were mis-delivered by UPS today! (Long story of lazy drivers here)

    Anyhow, I assembled one 2" track and sprocket set. The track pads have a lot of "grip" on a smooth surface.
    Dayum... are these things huge. I knew they were going to be big, but until I saw them next to Ted, I didn't realize just how big.No worries tho'. :lol:

    http://bit.ly/sWzngv
    http://bit.ly/ver5Lv

    Off to the local plastics vendor tomorrow to get material for a new deck.
    I'll have to re-design the front idler wheels... 6mm steel rod is a bit difficult to find off-the-shelf. Try to get the 6mm front hubs bored out to .25" and use some ball bearing pillow blocks.

    'Bout all for now.

    Happy weekending!

    Amanda
  • BamseBamse Posts: 561
    edited 2011-10-28 15:44
    Nice trax...

    Those tracks are going to look great on your bot...
  • Martin_HMartin_H Posts: 4,051
    edited 2011-10-29 04:05
    Those are some authoritative looking tracks.
  • ajwardajward Posts: 1,129
    edited 2011-10-29 10:39
    Just set up a deck for Ted's new look and did a test fit of the tracks. I think we're on the right track here... (Gibbs head slap for that one :-> )
    Gonna be about 13-1/2 inches wide and 12 inches long. Thinking about slinging the Prop board and battery underneath and leave the top clear for widgets.

    http://bit.ly/sPyUyd

    Amanda
  • Martin_HMartin_H Posts: 4,051
    edited 2011-10-29 12:07
    What are planning to use for batteries and motor controller? Don't let Erco lure you to the relay dark side. The way of the transistor is the path to enlightenment.

    BTW I finally copy Ted with TankBot and now you out tread me.
  • ajwardajward Posts: 1,129
    edited 2011-10-29 14:18
    Martin_H wrote: »
    What are planning to use for batteries and motor controller? Don't let Erco lure you to the relay dark side. The way of the transistor is the path to enlightenment.

    BTW I finally copy Ted with TankBot and now you out tread me.

    Initially, I'll start with a 9.6v rechargeable R/C battery pack. I have a half-dozen or so 12v sealed lead-acid batteries to experiment with.

    Motor control will come from the MSR1 Prop robot board. Just want to get it running, then try to get a little fancy. ;-)

    Amanda
  • CrazyrabbitCrazyrabbit Posts: 116
    edited 2011-10-29 17:08
    This is a video of my first robot a few years ago. I retrofittet matracks and upgraded to larger servos convertted to continious motion. There is a boe bot chasses in the middle believe it or not.It can carry some weight but has low ground clearance.Servos are much easier to control speeds and eat up less I/O .http://www.metacafe.com/watch/3155314/mini_monster_boe_bot_1/ You can see some of my earlier work as prettybird here before that listing stopped working. I learned the hard way simple is best.
  • ajwardajward Posts: 1,129
    edited 2011-11-02 10:14
    Hey All...

    A little more progress on the Lynxmotion tracks.

    I'm reusing the 7.2v motors and mounts from another project, but ran into a clearance problem. The motor shaft isn't long enough to allow the 2" tracks to clear the mount. After a bit of head scratching, I found if the mount was rotated 90 degrees so the mounting holes faced to the front, the obstruction just fit in the open area in the tracks. It's a =close= fit and there might still be a bit of contact 'tween track and mount, but I can live with that. (Can always rejigger it down the road!)

    My bracket...

    http://bit.ly/s6ODkD

    The motors and drive sprockets on the bracket...

    http://bit.ly/umDhfh

    Next up, mounting the front idlers.

    Amanda
  • ajwardajward Posts: 1,129
    edited 2011-11-02 14:45
    I've found if you're putting together the Lynxmotion tracks, a small plastic (or rubber) mallet makes the whole process a breeze!

    Also, their sprockets and hubs are designed to work with the tri-track chassis. That is... the sprockets don't go out to the edges of the track. They leave a row open to each side to allow for the plastic panels that cover the area within the track.

    http://bit.ly/uoE1Er

    Thinking perhaps I can diddle with the hubs/sprockets a bit to deal with this.

    Amanda
  • ajwardajward Posts: 1,129
    edited 2011-11-03 16:48
    @Crazyrabbit... Sweet 'bot. I'm partial to tracked vehicles. Hoping to build something fairly quick with video monitoring and remote control with the Xbee modules. Still a huge learning curve, but I have several experiments going on. ;-)

    Amanda
  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-11-03 20:17
    Amanda,

    Do you already have the XBee modules?

    If not, you might want to consider using a couple of Nordic nRF24L01+ modules. They cost less, are faster and are smaller than XBees. They aren't as easy to use as XBees but I wrote an object that makes using them with a Propeller pretty easy. Here's a link to a thread where they are discussed.

    I purchased some Nordic modules from eBay for about $7 each (IIRC). The fobs from SparkFun (discussed in this thread) use the same Nordic nRF24L01+ chips. (I would really like to learn to reprogram the ATTINY24 chips used on the fobs. They (the fobs) would make nice little remote control units.)

    Since the Nordic modules are so inexpensive and small, I've ended up putting them a bunch of my projects.

    Ron Czapala wrote a Basic Stamp version of the driver.

    Duane
  • ajwardajward Posts: 1,129
    edited 2011-11-04 11:36
    Ted Update...

    A bit of scrounging about town and I've completed the front idler wheels.

    http://bit.ly/tVZpZs

    I decided against the pillow block bearings... ~$40 for 2 pair and probably overkill. I went with a 6 x 45 metric shoulder bolt. The hub fits nicely and with a bit of lithium grease the hubs turn smoothly. I did have to ream out the center hole of the outer sprocket half to clear the bolt head.

    First idler mounted to the crossmember...

    http://bit.ly/tLSZZc

    With the pressure applied by the clamp, I have a bit of side-to-side adjustment for alignment.

    There should be less track tension as opposed to the Tamiya tracks and wear should be minimal.
    Going to mount the bolts to an aluminum angle under the front using a pair of stainless steel cable clamps (U-bolt sorta thingies). Spent about $15 for these parts.

    The propeller board is mounted to the deck and the battery pack is charging. Hope to have the mechanical work done today and the little critter moving under his own power over the weekend!

    Amanda
  • ajwardajward Posts: 1,129
    edited 2011-11-04 16:46
    Mechanical complete... almost.

    http://bit.ly/v4Zaxd

    http://bit.ly/rHhhPF

    http://bit.ly/rpWzNo

    The tracks are still a bit sloppy. I didn't build in any tension adjustment... no worries tho'... easy to fix!
    The way I used the aluminum angle leaves =very= little ground clearance, but he's intended for mostly indoor use.
    Calling it quits for the night. A bit of adjusting in the morning and I think we'll be ready for powered tests!!!! ;-)

    Amanda
  • ercoerco Posts: 20,255
    edited 2011-11-05 09:34
    Looks like 1/4" styrene sheet for the chassis? Strong, sweet, & glueable! MEK is nasty stuff, but makes a very strong solvent bond for styrene-to-styrene.
  • ajwardajward Posts: 1,129
    edited 2011-11-05 13:46
    Heya...

    @erco... PVC... I "think". Pretty soft and when I drill it, it behaves much like the pvc fittings I've worked on. I don't know for sure 'cuz it came from the scrap bin at Tap Plastics and for free they don't have much for descriptions!

    Got the minor clearance issues sorted out. Kind of a kludge, but I enjoy making things work... somehow.
    Working on a new motor mount design that will eliminate the clearance issues completely.

    Just powered up and all seems well. Now I just have to find the code to drive the motors. Fingers crossed!

    Amanda
  • ajwardajward Posts: 1,129
    edited 2011-11-05 14:37
    He lives!

    Haven't tracked down the code I had before, but fortunately the eeprom still had some instructions from another experiment.

    http://bit.ly/s0aowW
  • ercoerco Posts: 20,255
    edited 2011-11-12 08:52
    Another hack-worthy robot kit that Amanda & track-lovers everywhere might want to check out is the OWI Kabuto Mushi robot. Strange name, but it's a great kit with molded rubber tracks that work well, 3 selectable gear ratios, and a front-mounted claw that grips and raises up & down. IR remote controlled as delivered, and very nicely done. But it begs for autonomy and sensors! Under $40 new if you shop around.

    http://www.amazon.com/gp/product/B000VZB82I/ref=ox_ya_os_product

    http://www.youtube.com/watch?v=b6o_xdxWma8
  • ajwardajward Posts: 1,129
    edited 2011-11-12 10:56
    @erco... Kinda cool and I like the gripper. Watching it move tho' I'm thinking it might struggle a bit with a Foster's oil can. :lol:
  • ajwardajward Posts: 1,129
    edited 2011-11-12 10:59
    More tinkering with Ted. More clearance problems to sort out. I trimmed the Al angle bits to open more room. Just working on a rigid PVC pipe to mount the motors.
  • ajwardajward Posts: 1,129
    edited 2011-12-11 16:10
    More work with Ted. Performed some surgery on the aluminum angles under the deck to open more clearance.

    I installed a standard servo in the front for a Ping unit and two small breadboards at 45 degrees to the side for IR sensors and, possibly, others.
    http://bit.ly/tdN94a

    @
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