I want a set of the moduals so i can finish my swerve drive for vex. but assumed there not a very popular item on the site so ive waited patiently…for like 3 months. there still not restocked…what going on? Any incite?
We redesigned the Swerve Modules. The new ones should be in-stock sometime this summer. Sorry for the delay, but as you said these are not a very popular product, and not very high-priority.
Should be out soon!
-John
what? really?? thats awesome! yea i was always having problems mounting them to a frame and keeping them from shifting around. since the only thing that could support the module was the axle supplying power to the wheel. i hope you introduced a ball bearing turntable into the set, that would make life soo much easier. it would also be awesome if you included special gears that were more like rings that mounted very easily to one of the sides would also be a very convenient feature. Something like this would be perfect:
http://www.servocity.com/html/ball_bearing_turntables.html
hopefully this is what you changed. 
oh I’m excited for this
thanks for replying
Well… you’re probably going to be disappointed. Nothing that cool, just some “usability” improvements.
We made a change which replaced the 60-tooth spur gear with a high strength 60-tooth gear. This new design is much simpler, and results in a better turn-table (not as good as the ball-bearing lazy susan you linked to). This change also removes the need for users to “thread” a screw into the square axle hole of the 60-tooth gear (something several users have complained about).
-John
The turntable would be super nice. I hope you guys decide to throw that in on the third pass. oh well. Least your making it a high strength chain gear. The modules i made used the normal gears. I soon realized that would have to change. The small chain flexes and the wheels would get easily out of alignment. What do you mean by thread a screw into the center of the gear? Is that for people that are doing coaxial swerve drives with the motor directly mounted to the modules? Idk. Mine is non coaxial, as in the motor is next to the module and drives the wheel through the top of the module on the rotating axis and with bevel gears. I had to rip the center of the gear out to achieve this. You should do the same thing you did with the high strength gears. You should add inserts to the high strength chain gears so i could just use 2 round inserts and achieve the same effect instead of having to tear a gear apart. I’m surprised that more teams don’t do swerve drives for vex. idk maybe because holomonic drives are alot easier. But with the high strength motors, you can get away with using 2 of them, then using one regular motor to make all the wheels spin. Thats the idea that I’m trying to show on my team. Maybe it will catch on with others
60 tooth gear, not sprocket, so you can put a round insert in apparently.
Personally there’s a few reasons I think swerve drives haven’t really caught on. You only had one gearing option before this year without going coaxial, and direct driving the small wheels isn’t a competitive speed. Secondly, until this year every game had either terrain or Clean Sweep’s wall in the field. The former made omnidirectional movement tricky while the latter made holonomic drives more effective as traction didn’t matter. This year, while it’s an option (high strength motors in high gear give you a much better speed), the motor commitment of 5 motors combined with added complexity will make a swerve drive have significant drawbacks that teams need to carefully consider.
oh god no. i wouldn’t use five motors for a swerve drive. i would make mine non coaxial so i would only use 3. 2 HT motors would control a pair of wheels then i would use a regular motor to turn them. Thats the best way to use up your 2 HT motors you can use. (because with more, you run in to amp problems…) >.>
vex should release a cortex micro controller with better breakers. Everyone will buy those.
I was assuming a four wheel swerve drive. A two wheel 2 caster swerve loses a lot of the advantages in my opinion…
You can use 4 HSMs with a Cortex, it’s all a matter of gearing and load analysis. I wouldn’t use anecdotal evidence alone to define hard limits on what you can do with your hardware; I would use experimentally determined data or your own prototypes.
I would still have 4 rotating wheels. but i would have one HT motor control 2 wheels. So i would use 2 motors to drive four wheels.
The problem is with the HT motors, the Amps stay manageable until you start throwing on the other regular motors. Thats where you hit problems.
Saying that swerve modules are out of stock is just plain silly
There are pictures of some right here that have never gone “Out of stock”.
https://vexforum.com/gallery/showimage.php?i=483&original=1&c=member&imageuser=757
https://vexforum.com/gallery/showimage.php?i=484&original=1&c=member&imageuser=757
https://vexforum.com/gallery/showimage.php?i=485&original=1&c=member&imageuser=757
[https://vexforum.com/gallery/showimage.php?i=486&original=1&c=member&imageuser=757
The long lower posts are screwed into the plate and the plate is screwed into the gear.
The short upper posts have screws screwed into their lower tips and the screws’ heads slide fairly smoothly on/along the rim of the gear.
The gear has an axle through it and the whole lower assembly revolves around the hole/axis where that axle passes through a hole in the chassis.
Blake
PS: The mechanism is far from perfect, but it does work. When/if you improve it, please post a picture.
PPS: I remember seeing a picture of a bot that used swerving wheels to choose where it would go in a straight line and used skid steering to accomplish turns. The 4 motorized wheels swerved the same direction at the same time. They swerved together because all 4 wheels were slaved together by a large collection of interconnected gears. The interconnected gears formed a continuous rectangle around the top perimeter of the bot (or maybe they were just on 3 sides). I thought that was a neat idea/compromise.](https://vexforum.com/gallery/showimage.php?i=486&original=1&c=member&imageuser=757)
this is a prototype of one of my swerve modules
http://img833.imageshack.us/img833/5325/swervedrivethingy.jpg
my plan is to use a motor outside of the module to power it. hence the bevel gears at the top. i have to use a high strength sprocket chain at the top instead of the normal one. which i have not done yet.
Looks neat!
I have two worries - I think the first one has been raised earlier. Regardless, I have wanted to try using the bevel gears they way you are using them, but just haven’t had the time to do it. So I am really curious (and hopeful) how well they work out in your final design.
-
It looks like you plan to use the small chain to rotate the modules. I worry that the small chain will have too much slop and will slip occasionally. Those will make it hard to keep the modules aligned. To avoid the slipping, you might need to use some extra sprockets to create a chain path that forces the chains to wrap around most of the module sprocket.
-
The wheel isn’t centered under module’s rotation axis That is going to give you some odd steering nuances and apply a torque to the entire module. That torque is going to fight against any attempt to hold the module still in any single orientation (and it might win the fight…).
I suspect that you will be able to substitute some stand-offs for the module metal (like I did) if you want; and if you do that, you might be able to find enough room down there to center the wheel.
Good luck, Let us know how it turns out.
Blake
Actually, he says that he will, but has not yet, switched to high strength chain and sprockets on the top of the module:
Jordan
You “might” not need the set screw in front of the bevel gear. I’d like to think that the other bevel gear would prevent the horizontal gear from sliding forward. Optionally, you also “might” be able to bump the gears up one peg. This should let you center the wheel.
im trying to remember why its not at the very top…it might have been bc the gear would hit the metal at the top or something…
i think its to stop the axle to stop slipping?
cant see if there is another lock on the other side of the axle
To prevent axle movement in that direction you could put a set screw on the outside right, which looks like it has plenty of room for one.
I’ll play around a little in CAD with the old swerve bracket to see where the geometry conflicts for a higher bevel gear.
oo post what you find out
Swerve Kits are back in stock…
http://www.vexrobotics.com/products/accessories/motion/276-0506.html
I’m sorry for the delay!
and apparently it’s New and Improved!! with a high-strength gear.