At long last I finished the Trash Bot's chassis. You can build your own Take Out The Trash roBot (TOTT Bot). Just read on to see the design and find out what Actobotics parts I used...
I built an initial version of the chassis a few weeks ago and have since refined it. I've also settled on a better way to grab and tow the trash cans. So here goes.
Towing DesignThanks to brilliant input from clever readers, the new design involves towing rather than lifting the trash cans. It seems simpler and quicker to implement. Lifting or grabbing the handle may come later but are too involved given time constraints.
|Please forgive my crummy drawings :)|
That's engineering for you. Evaluate the options and sometimes realize they all suck, throw them out, and come up with a better option. Find the optimum solution, adapt to change.
Change? Yeah. My requirements changed, midstream. Time-to-implement became more important than my requirement against modifying the trash cans. I think the new solution will still be trash-collector-friendly but quicker to implement (heck, I'm almost done, in fact).
Since they're cheap and you need a bunch, stock up on the above, get at least the recommended amount. You'll want to double-check my counting, too.
- (2) 1/4" 6-32 Socket Head Machine Screw, 25-pack (632106)
- (3) 5/16" 6-32 Socket Head Machine Screw, 25-pack (632108)
- (1) 3/8" 6-32 Socket Head Machine Screw, 25-pack (632110)
- (1) 7/16" 6-32 Socket Head Machine Screw, 25-pack (632112)
- (1) 5/8" 6-32 Socket Head Machine Screw, 25-pack (632118)
- (1) 9/16" 6-32 Socket Head Machine Screw, 25-pack (632116)
- (1) 15" Aluminum Channel Product Page (585458)
- (1) 18" Aluminum Channel Product Page (585462)
- (2) 12" Aluminum Channel Product Page (585454)
- (2) 9" Aluminum Channel Product Page (585450)
- (6) Side Mount Bracket Pair Product Page (585470)
- for each pair, use (4) of the 1/4" Machine Screws
- for each pair, use (4) of the 5/16" Machine Screws
- (2) Quad-D Hub Mount Product Page (545324)
- Attach to channel with (4) of the 5/16" Machine Screws
- (2) 0.5" Tube Clamp Hub, 0.5" bore Product Page (545340)
- Attach to the Quad-D Hub Mount with (4) of the 3/8" Machine Screws
- (2) 0.25" Clamping Hub, 0.5" bore Product Page (545600)
- Attach to channel with (4) of the 3/8" Machine Screws
- (2) 12" x 0.5" hollow tubing Product Page (635262)
|Side Mount Brackets on an Aluminum Channel|
|Side view of front where tubes are mounted.|
- (2) Channel Bracket B Product Page (585482)
- (2) D-Shaft 0.25" x 2.5" Product Page (634074)
- (4) 0.25" Collars Product Page (6432K12)
- (1) 0.25" Shaft Spacers, Pack Product Page (633104)
- (2) 0.770", 0.25" Set Screw Hub Product Page (545548)
- (2) 4" Heavy Duty Wheel, 0.770" pattern Product Page (595410)
- (2) 90 degree Hub Hub Mount Product Page (545400)
- (2) 0.5" Tube Clamp Hub, 0.5" bore Product Page (545340)
- Attach to the 90 degree Hub Hub Mount with (4) 5/8" Machine Screws
- (2) Swivel Hub Product Page (545364)
- Attach to the 90 degree Hub Hub Mount with (4) 1/4" Machine Screws
- Attach to the Channel Bracket B with (4) 1/4" Machine Screws
- (4) Flanged Ball Bearing 0.25" ID, 0.5" OD Product Page (535044)
The Swivel Hub mounts onto the 90 degree Hub Hub Bracket and Channel Bracket B with 1/4" machine screws. The Tube Clamp Hub mounts to the other part of the Hub Hub Bracket with 5/8" machine screws. Don't tighten those screws yet.
The Tube of course goes into the Tube Clamp and then you screw down the clamp screws. Once those are tight, then finish by tightening the Tube Clamp to the Hub Hub Bracket. For better grip, sand the tube with 220 grit sandpaper.
The wheels mount to the Channel Bracket B as follows. Use the 0.25" D-Shaft and onto that you use a pair of Collars (or add another, inside the Channel Bracket B if you want to make the assembly more secure), a Bearing each side, a single 0.770" set screw hub adapter, and the 4" heavy duty wheel. I put plastic shaft spacers between the bearings and collar though that isn't strictly necessary.
|This is one side of the caster axle assembly|
|This is the other side of the caster axle assembly|
- (4) Bearing Mount - Pillow Block Round (1" Bore) Product Page (535170)
- Attach each to 9" Channel with (2) 5/16" Machine Screws
- (4) Clamping Hub 1" Bore, Threaded Product Page (545352)
- (2) Aluminum Set Screw Collar, 1" Bore Product Page (9946K19)
- (2) 6" Heavy Duty Wheel Product Page (595610)
- Attach each Clamping Hub to each Wheel with (4) 9/16" Machine Screws
- (2) 48T Sprocket, 1" Bore, 0.25" pitch Product Page (615126)
- Attach each Clamping Hub to each Sprocket with (4) 5/16" Machine Screws
- (2) 16T Sprocket, Hub Mount, 0.25" pitch Product Page (615102)
- (2) Set Screw Hub, 6mm bore Product Page (545576)
- Attach to 16T Sprocket with (4) 7/16" Machine Screws
- (2) 4" x 1" Stainless Steel Tubing* Product Page (635138)
- (2) 90 RPM Precision Gear Motor** Product Page (638238)
- (2) Aluminum Clamping Motor Mount Product Page (555116)
- Place motor in mount, clamp, attach to 9" Channel with (2) 7/16" Machine Screws
- (3) 12" lengths of 0.250" Plastic Chain Product Page (615150)
- (4) Shaft Spacer, 1" Product Page (633116)
** I may need to select more powerful gear motors. We'll see.
I selected a chain dive configuration as it was easiest to assemble. The gear motor provides gear reduction already but I added 1:3 reduction with 16T and 48T sprockets, thereby tripling torque and reducing speed by one third.
|Robot is rotated 90 degrees in this picture. Front is at the top of the shot.|
Mount the Wheel onto the Clamping Hub, loosely, insert the 1" axle tube flush with the wheel, clamp down the hub, then tighten it to the wheel. Next, slide on the collar and clamp it in place. Finally, slide on a Spacer. Slide the free end of the axle tube into the pillow blocks.
Slide a Spacer onto the other end of the Tube followed by a Clamping Hub. Attach the 48T sprocket onto the clamping hub loosely, then slide this assembly onto the Tube. When clamping down the Hub, leave just enough side play to ensure low friction rotation. You may have to play with it a bit. Clamp down the hub, tighten the sprocket to the hub.
Attach the Motor Mount onto the 9" Channel. Insert the 90 RPM Motor and clamp down. Attach the 16T sprocket onto the 6mm Clamping Hub. Slide onto the Motor shaft. Slide the sprocket along the shaft until it is co-planar with the 48T sprocket below. Tighten the set screw.
Connect two 12" Chain lengths together, measure it around both sprockets, remove unneeded links. Stretch the loose ends and attach (this is hard). A little slack in the chain is ok, as long as it can't easily jump on the sprocket.
ConclusionThat's it for now. Next time I'll write about the towing mechanism on the robot. After that I'll be working on electronics.
As always, enjoy following your work on this project. We have decided to build a miniature version first, posting our progress here:ReplyDelete
We are thinking that a forklift approach with side bars to prevent from falling side to side or forward may work. We'll put a wireless camera on it, so to watch progress from our computer.
Look forward to seeing your progress!!
I'm happy that you have gotten as far as you have on this but I gotta be honest, I'm kinda bummed. I Googled "trash can robot" a while back and didn't find much and had a bunch of ideas. I was gearing up to build a prototype and was thinking about having a kickstarter and everything and then I found this. Which isn't to say I can't still do mine... it's just I've been trying to invent something, anything, for a long time and every time I think I get close to something original i find out the word haa beat me too it. You are also way better at math and engineering than I am. I was in mechanical for a while at Louisiana tech but I had to stop. The math alone can be brutal. I'm a big concept guy, but if you can't make your concept real then what's the point ya know? I want to make dreams real. That's it. I'm not looking for any attention or trying to have a pity party. It's worth noting I've been very depressed lately so idk. Anyway i like what you are doing and can't wait to see the finished product. God bless.ReplyDelete
I can relate to much of that. Seems every cool project I start, someone else has already completed and gotten published on hackaday before I've gotten half done. With billions in the world it is nearly impossible to be the first -- BUT that actually doesn't matter. The reality is many have succeeded in being second or third. Apple Newton vs Palm Pilot. As long as it is taking me to build the smarts on this trash bot you or others could easily beat me. I am better at making improvements than coming up with lots of original ideas. That has its own set of frustrations and bummers. I really think the answer is teamwork and luck. I've fought depression since at least age 20. I became about 10x more productive in my hobby robotics after getting that under control with medication :)Delete
How goes this project? Can't wait for the next part as I'm working on something similar! Although I now have a 2 year old son who will be my trash-taking-out robot in a few years time. ;)ReplyDelete