What Drivetrain?

[ekapalka]

To the people selecting "other", could you explain? Thanks!
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[Walter Deitzler]

Originally Posted by ekapalka

To the people selecting "other", could you explain? Thanks!
~

Our robot: http://www.chiefdelphi.com/forums/sh...=3397+Serenity

It runs two wheels in the front, a floating omni-wheel in the back. It does not really fit into any of the categories that were provided, I believe it is called a "kiwi" drive, which is not on the list.

If you want reason as to why we went with this design, all of the details are in the thread linked to earlier.

[Boe]

Originally Posted by LedLover96

Our robot: http://www.chiefdelphi.com/forums/sh...=3397+Serenity

It runs two wheels in the front, a floating omni-wheel in the back. It does not really fit into any of the categories that were provided, I believe it is called a "kiwi" drive, which is not on the list.

If you want reason as to why we went with this design, all of the details are in the thread linked to earlier.

A kiwi drive has 3 omni wheels all driven offset at 120 degree angles from each other the only team i know of that did one this year was 1425 but im sure there are others i havent seen. you can kind of see the drive in this video http://www.youtube.com/watch?v=jWGYa...ature=youtu.be

[Djur]

Originally Posted by ekapalka

To the people selecting "other", could you explain? Thanks!
~

"Other" = no drivetrain.

[Walter Deitzler]

Originally Posted by Boe

A kiwi drive has 3 omni wheels all driven offset at 120 degree angles from each other the only team i know of that did one this year was 1425 but im sure there are others i havent seen. you can kind of see the drive in this video http://www.youtube.com/watch?v=jWGYa...ature=youtu.be

We called our a "stingray" drive, due to the shape of the frame. I was just told by someone that it was kiwi, thanks for clearing that up.

[Ether]

Originally Posted by Boe

A kiwi drive has 3 omni wheels all driven offset at 120 degree angles from each other

The inverse kinematics for Kiwi are very simple and are shown here on one page.

[Tom Line]

Originally Posted by Adrian Clark

Has anyone else had this problem with hex bearings?

I'm curious because I know they're other teams that run WCD's with hex bearings and to my knowledge they don't have any problems.

How exactly were your bearings configured on your WCD? What was your bearing block setup like? How close together were your bearings? Did you do anything very different from the stereotypical WCD in your drivetrain?

-Adrian

Yes. We destroyed probably a half dozen bearings in a non-loaded low speed application. We ended up not using that particular mechanism on the robot. However, the incidents of failure left us with a very low opinion of the current generation of hex-bearings.

Our application was single shaft non-cantilevered (supported by bearings at both ends). The bearings blew out sideways after the races cracked.

[DampRobot]

Originally Posted by Tom Line

Yes. We destroyed probably a half dozen bearings in a non-loaded low speed application. We ended up not using that particular mechanism on the robot. However, the incidents of failure left us with a very low opinion of the current generation of hex-bearings.

Our application was single shaft non-cantilevered (supported by bearings at both ends). The bearings blew out sideways after the races cracked.

That's amazing... I've never seen anything like it. We used hex bearings, and even Vex Pro hex bearings, on very high axial load, high torque and cantilevered shafts without any problems. Perhaps there was a bad set?

[Adrian Clark]

Originally Posted by Tom Line

Yes. We destroyed probably a half dozen bearings in a non-loaded low speed application. We ended up not using that particular mechanism on the robot. However, the incidents of failure left us with a very low opinion of the current generation of hex-bearings.

Our application was single shaft non-cantilevered (supported by bearings at both ends). The bearings blew out sideways after the races cracked.

Interesting. Were these were vexpro bearings?

[apples000]

The VexPro hex bearings are complete garbage. All the other parts from vex pro are well made, and designed with attention to detail, but the hex bearings are awful. We have an older robot for demonstrations that has a transmission that uses a hex bearing (not on a cantilevered shaft). For 6 years and thousands of cycles in competition and at demonstrations, the original hex bearing worked. Then, we took apart the mechanism for cleaning, and we decided to try out the vex pro hex bearing. After 3 cycles of the arm, the bearing failed completely.

[Teamcodeorange]

Originally Posted by Tom Line

Yes. We destroyed probably a half dozen bearings in a non-loaded low speed application. We ended up not using that particular mechanism on the robot. However, the incidents of failure left us with a very low opinion of the current generation of hex-bearings.

Our application was single shaft non-cantilevered (supported by bearings at both ends). The bearings blew out sideways after the races cracked.

Same as us. Bad bearings, don't do that.