I like the single tooth drum, that must have taken some balancing.
Printable View
I like the single tooth drum, that must have taken some balancing.
@Nick: That is an option, yeah. I had the bore left at 25mm because in the event of the drum getting a massive, bearing disintegrating hit, I can pop some 25mm OD 20mm ID bronze bushings in there (I'll make some spacers to fill the bearing pockets) and get a form of weapon for a fight or two. I doubt the alu shaft will enjoy that much but if it's the difference between a win and a loss the shaft can get remade!
There are so many variables weight-wise that I could be half a kilo under or over. :) #planning
edit: thanks David, I don't yet know what the balance is like (this is all still with Jeroen), but it should be close to negligible as-is, if not I can take some material out of the drum and get it bang on.
Those roller bearings should take major punishment but its always good to have a plan B. Looking at the photos again, what's stopping axial movement along the shaft? That's the weak spot for the roller bearings; are you using thrust bearings between the ends of the drum and the frame?
There will be spacers/shims around the shaft between the bulkheads and the bearings, putting a bit of preload on the rollers and spacing them between the bulkheads. Very similar to Dave's 720, as that seems to work well. He knows imitation is the purest form of flattery. ;)
This year i'm covering 720 up between fights and getting an armed guard...everyone seems to be stealing my ideas lol
looks good though- how come you didn't use the bulkheads to pre-load the bearings like on 720 and take it as an opportunity to fit a wider drum? To heavy? What is the total weight of your drum btw?
@ Dave: Too late; look out your window - is that a drone circling your place RIGHT NOW? :)
Hope not, i'm at work lol
Lol. Inb4 titanium drum for Rango in 2015.
I'm not sure how I could get preload on the bearings differently when they sit behind the discs as they do. Could have used thrust bearings or something between the bulkheads and the faces of the discs, but it's more fuss than it's worth I think, for a slightly wider drum. The clearance is 2mm from the boltheads to the bulkheads as it is, I'd have to use weaker headed bolts to make it wider.
Also the spinning mass will be about 2kg, maybe a tad over, at around 8000rpm. Never intended for the weapon to be the main aspect of the robot, I think Harry described Rango once as a jumped up rambot and that sounds accurate to me. :P
You made a rambot with where the weapon is more reliable than the drive. You're special.
Jeroen has done more work on the drum, and it's now nearly ready to send. He has put loads of time into this, and has supplied nothing but quality and knowledge with a speedy turnaround. Couldn't be happier.
http://i1088.photobucket.com/albums/...3-24233739.jpg
http://i1088.photobucket.com/albums/...g?t=1395706268
Meanwhile in the mudshack I call a workshop (:)) I have modded the wheel pulleys. 3 bolt holes each and a large bore to accept the biggest bushing I could make that still had a small flange, so there's less heavy steel and more air-light oilon. Drilling the-
http://i1088.photobucket.com/albums/...g?t=1395706405
-half-holes sucked!
http://i1088.photobucket.com/albums/...0435shrunk.jpg
Also now organised is the watercutting for the 3.2mm hardox wedge, through Mario, who will also be welding it up.
It will all hopefully be in my hands a week or so before we leave. What even is planning?
Is there a reason for not using aluminium timing pulleys? Steel seems overly strong and must add a heap of weight.
No, and it does. It's me not realising HTD5 pulleys are steel from the supplier I got HTD3 ones in aluminium. I thought these would be aluminium too (it does say they're steel, but apparently I don't have eyes). I got a surprise when I felt the box they were shipped in, let me tells ya. Simple case of assuming, and assuming wrong.
This is an area I should be able to save serious weight for future upgrades. Too late now, unfortunately. Even aluminium seems stronger than necessary, I'd quite happily use a plastic variation if they could be sourced.
I once got some plastic timing pulleys to go on a wheel design like yours. I can't recall what type of belt they took, but they were a similar size and came from SDP/SI in the USA: https://sdp-si.com/eStore/Catalog. They may even have a local reseller or you can sometimes work out the original manufacturer from the spec.sheets and Google a closer source. Hope that helps in the future...
Cheers, I will do some searches post-champs. I feel ridiculous for making the assumption, and I should have checked, but I now know I won't do it again in a hurry, so not all is lost.
QTC sell nylon HTD5 pulleys, but they're in New York, and probably cost masses anyway. Website is messing around so can't find out. Pretty sure I could source aluminium ones in the UK, or alternatively another competitor (Alex) is 3D printing HTD5 pulleys. His setup is different to mine but if his work that may be by far the easiest/cheapest option. It could save me the guts of half a kilo, going with plastic!
Heavier drum for 2015 methinks.
Heavier drum? On second thoughts, make the pulleys out of depleted uranium! :lol:
That drum looks pretty evil, and the power behind the drive's going to make it hit a lot harder... going to be one to watch I bet!
Have you figured out what speed the machine'll be able to get up to?
Yay reading.Quote:
Originally Posted by Ellis
Lol
And that's why I shouldn't be allowed on the forum past midnight. Thanks there Harry!
Going to have a heck of a hit though, imagine that ploughing into the side of a machine at 15mph and the drum going at full speed...
That's the plan! Though the drum shouldn't have too much kick, the design isn't optimised for packing an inertia-loaded hit, and the spinning mass is actually a little under 2kg. I'm hoping the single tooth means, though overall energy stored is quite small (relative to other spinners), it should dump said energy into the enemy more often, or more effectively. All I'd like it to be able to do is roll robots over, anything more is a bonus.
Small update, Jeroen has now sent the box of goodies. Hoping it'll be here sometime mid next week.
I have been making some of the fiddly bits. I was going to not bother with motor shaft supports but figured for what they'll add in weight, it's worth it:
http://i1088.photobucket.com/albums/...0445shrunk.jpg
The combined effects of the kind of gear teeth and the braking function fighting the robot's momentum when coming to a stop means the pinion will get pushed and pulled in all directions. This little plate, once tightened down, should at least limit by how much the 5mm motor shafts can flex. The stubby bronze bushing captures the end of the motor shaft:
http://i1088.photobucket.com/albums/...g?t=1395927887
Also made the bearing block for supporting the other side of the right angle shafts. Some semi-pretendo 4 u.
http://i1088.photobucket.com/albums/...g?t=1395927643
http://i1088.photobucket.com/albums/...g?t=1395927640
Going to go and bolt the pulleys to the wheels, which allows me to see where the belts will finally run (and if the wheel bushing alignment is going to be off), so I can make other bits and plan the electronics positions from there.
Looks great really neat and compact can't wait to see the drum on it
Your robot is so gosh dern bitsy its wonderful. So many parts too it. Hope you don't need to take the everything apart too much.
Wow :O
That's awesome, keep going, theres's still like, a week or so till the competition,
That all looks awesome Ellis! Looks like we are both taking a step up in terms of engineering and quality!
We have been saying it for 3 years, we need to have a fight and a tug of war!
That'd be well funny to watch...no shirts or shoes. Then we could go back to the robot stuff...
Rofl^ / cheers guys, yeah it's a bitsy thing, about to get even bitsier with electronics mounting. Want to actually mount the internals in Rango, because some guy designed it with a load of belts going everywhere. Going to mean a lot of small standoffs and tiny plates!
Also, the wedge has been watercut, and Mario has already welded it up. He's doing some work for T2 as well, so it'll be couriered to here sometime next week, hopefully alongside. It's 3.2mm hardox and weighs 1kg.
http://i1088.photobucket.com/albums/...g?t=1396027024
http://i1088.photobucket.com/albums/...g?t=1396027166
It's slot-and-tab to make positioning for welding straightforward, and the mounting brackets are slotted so I can set the height depending on who I'm fighting, or leave it loose and have it *hopefully* completely ground-scraping.
The pulleys are now bolted to the wheels which allows me to see where exactly the belts will all pass, so I can now start to position internals around them and devise mounts. Not done much buildy stuff today, the chassis is on the floor and I'm throwing speed controllers at it to see how they fit.
Looking good Ellis... like how your putting a lot of thought into everything =)
In regards to those motor shaft protectors... great idea, just make sure you get some full length sleeves/standoff tubes on those bolts if you can... will be much stronger if the base of the standoffs can press up against the motor casing rather than resting on the shaft bearing neck like you have now in the pic (will reduce unwanted sideways flex)
I'm assuming you have them where they currently are, because they are too large in external diameter to slide past the bearing neck, but if you get some longer standoffs, and use a grinder/dremel/flatfile... you'll be able to remove some material off of one side of the standoffs, so that they slide down to the motor case end.
Obviously you wouldn't need to file the whole side down, just the length that would need to pass the bearing neck on the motor casing.
Possibly overkill... but another thought might be to get a washer and a thrust bearing in between the gear face and the brass bushing you have there... then again it does look like you could be pressed for length on the protruding shaft *giggdy
so you could mill a larger hole in the brass bushing you have there, then lathe a brass collar that fits over the shaft but inside that recess in the end gear... then the thrust bearing could be cupped by your retainer and sit on the top face of the lathed brass sleeve.
If your gram counting and are wanting to be this meticulous, you could tack weld some needle bearing cartridges onto those steel plates you have holding the brass bushing instead...
food for thought, that my random 2 pence in anyways haha
Hi RoboLibre. Thanks for the post. The standoffs fit fine and are free to go wherever, it looks like they clash but they are clear of the motor boss by miles. They're the short length they are because the 10mm thick motor mount plate (not yet made up) is what they tighten onto, and I can easily adjust their length for a nice frictionless support on the motor shaft. I don't think a bearing in there is worth it; space is very limited (12mm OD is the limit) and the bronze should last plenty long enough for a competition or two. Can always make up spares. I cleaned up the front of the pinions so that they are smooth, with a bit of grease wear should be minimal. The bronze doesn't even touch the gear under no load anyway.
Have tested the motor with and without the support and there is no audible difference, no heat in the bush and no apparent issue change in start up speed. That's without any grease.
It'll be just fine lol.
Sorry for the double post. Been testing the electrical side of the machine, and have come across an issue. I suspect (and sincerely hope) the problem here is born from lack of knowledge and general noobiness. Any help appreciated.
https://www.youtube.com/watch?v=7RuAjHZU-6Q
I sound all racey in the video, was a bit disappointed, I wanted it to go whizz!
Thanks.
Are you phases correct on the motor, are they both matched ie non sensored, if so sounds like a dead motor never had that problem before on a model car setup ran many over the years
Have you run it without the mount? Perhaps the mounting screws are causing the motor to stop turning... I know that's pretty unlikely, but it might be worth a check? If not, then I'm not sure what it could be other than a setup error or a dodgy motor
If the motor's getting that warm from that short time it was in use in the video, it would suggest that there may be a problem internally, something that's increasing the resistance. I'm pretty sure even the cheapest of brushless motors shouldn't get that warm that quickly. Could be something that hasn't been mounted concentrically on the shaft and is rubbing on the insides of the can or it could be, as Matt touched on, the mounting screws on the front are just a tad too long and are touching the internals.
Try it the same way as the Align, i.e. just being held in your hand without the mounting plate attached. If the problem still persists, then the motor's probably gubbed. It could just be some setting on the speed controller that needs adjusted but I reckon that's less likely since you've proven every other aspect of the setup with the Align motor connected.
Thanks for the responses guys. Naturally, as I made the plate, I double and triple and quadruple checked the screw lengths, they're plenty out of the way, but I just tried it off the mount and it behaves the same.
The motor and ESC are both sensorless.
Reviews on HK are very positive for this motor, so I may do best to try and get another one, but naturally I'm put off. There aren't many alternatives in my price range, sadly. The Align is usable but I think the poor thing will give up before long, it's had a hard life. :P
Not sure what to do!
By the time you kill the motor I'll be out of the competition so you can have Massacre's inrunner for silly speed. Or you can have the 35mm Outrunner of Shame ;)
Buy another one asap, you're already in minus money so another 30 quid won't hurt (that's about what I owe you anyway :P)
Put in the Align for testing.
Order another motor, and claim refund on the one you have.
Sounds like you've lost a phase in the motor. That also accounts for the heat as it might short inside the can.
I have spoken to a tech guy at Hobbyking, through their live chat system, and amazingly it was very useful. The guy was asking questions, watched the video, making suggestions, and very clearly knew his stuff. Got to hand it to HK, I'm pleasantly surprised.
He thought it might be ESC setup. I think by default the YEP150 is designed to run outrunners (the Align is in fact an outrunner enclosed in a case, I called it an inrunner to avoid confusion, this guy knew his stuff enough to point this out) which would make sense in that case. I don't have a programming card, but we're going to try and set up the PWM and timing to run the Turnigy as per his suggestions, via the Spektrum.
Will keep this posted, I hope we can solve it. Really don't want to have to get into ordering a replacement this late in the game!
I doubt being setup as the wrong type would make that much difference.
I presume you tried cutting the power to the esc, then recalibrating it with the correct motor? A lot of escs won't like a motor being swaped like you did in the vid, it will need calibrating. Also if you can change the timing to high other than the stock settings it might help.
To prove the motors good you need to check the phases are balanced with a multimeter. Check the resistance of the phase wires against eachother... They should all be pretty close... If there not, it's the motor. Also check the motor phases to earth (in this case the motor case) to see if something's shorting.
Yeah we have tried all different timing and different PWM ranges, still not running right at all. They do have an effect but it's gutless regardless. Still gets hot regardless, too.
Also yes, we have re-calibrated with the turnigy several times, same behaviour.
Haven't tried the checking to earth, will do next. Looking more and more like a dud.
edit: checked, all is correct. I can't think of any other reason for this behaviour, other than the ESC and motor simply not being compatible, but there is no mention of limitations in the product description for the ESC.
The motor didn't seem to be turning at all to start with. If you give it a kick-start by manually turning the shaft, does it start running? That's a symptom of a bad phase I saw on one of the bots over here. It could be an internal short, which accounts for it warming up so fast. one other thing to look for is wear around where the wires enter the motor case. You might find the insulation has moved or worn through, or that some of the wires have gotten metal fatigue and snapped. That would be hard to fix but its worth knowing why the motor broke so you can avoid it in the future.
I'm with the other guys; its time for a replacement motor.