Hex Kiwi Drive

[asid61]

That might be a tad fast even for 6 CIMs, because of brownouts. Apart from that, I really love this implementation.
Your CIMs appear to be bleeding into the bellypan.
Have you thought about using the Vex clamping gearboxes instead of custom? I like your implementation as it keeps this low to the ground, but it's something to think about.

EDIT: Missed the upper fame. As Jay said, adding some 2x1s or something with cuts to that they fit into the main rail and upper rail would be much more secure.

[caume]

Originally Posted by asid61

Your CIMs appear to be bleeding into the bellypan.
Have you thought about using the Vex clamping gearboxes instead of custom? I like your implementation as it keeps this low to the ground, but it's something to think about.

My original version of the cad actually used the vex clamping gearboxes. My team has had problems with motors sagging down, so I went on to make the motors lower, with cutouts in the bottom plate. The idea was the bottom plate would support the motors a bit. I attached the other images.

[messer5740]

So I have difficulty seeing what previous game a hex chassis would be effective for. Would someone care to enlighten me on what benefits there are for having a hex chassis? I feel that an H drive or mecanum is a more efficient way of driving for you still have the omnidirectional movement. Also, with the electronics that would need to be added, I do not see how attachments could go onto the robot without having a tangled mess of wire and electronics on the belly pan. Perhaps even an additional pan would be good for adding attachments... I know Simbotics used a kiwi drive in 2015 in a non defensive game, but their chassis was not a hex like the one shown above. So why Hex and why kiwi?

EDIT: can you send me the CAD so I can review it some more?

[caume]

Originally Posted by messer5740

So I have difficulty seeing what previous game a hex chassis would be effective for. Would someone care to enlighten me on what benefits there are for having a hex chassis? I feel that an H drive or mecanum is a more efficient way of driving for you still have the omnidirectional movement. Also, with the electronics that would need to be added, I do not see how attachments could go onto the robot without having a tangled mess of wire and electronics on the belly pan. Perhaps even an additional pan would be good for adding attachments... I know Simbotics used a kiwi drive in 2015 in a non defensive game, but their chassis was not a hex like the one shown above. So why Hex and why kiwi?

Hex kiwi could be really good 2014, or any flat field really, because it can be so fast and maneuverable

[messer5740]

So how would you be able to get a shooter or kicker on the robot?

[CalTran]

Originally Posted by messer5740

So I have difficulty seeing what previous game a hex chassis would be effective for. Would someone care to enlighten me on what benefits there are for having a hex chassis? I feel that an H drive or mecanum is a more efficient way of driving for you still have the omnidirectional movement. Also, with the electronics that would need to be added, I do not see how attachments could go onto the robot without having a tangled mess of wire and electronics on the belly pan. Perhaps even an additional pan would be good for adding attachments... I know Simbotics used a kiwi drive in 2015 in a non defensive game, but their chassis was not a hex like the one shown above. So why Hex and why kiwi?

EDIT: can you send me the CAD so I can review it some more?

To be fair, 148 won a Championship with a nonagon chassis.

[Alan Anderson]

Originally Posted by CalTran

To be fair, 148 won a Championship with a nonagon chassis.

The frame had nine sides, true. Count the wheels, though.

[messer5740]

Originally Posted by Alan Anderson

The frame had nine sides, true. Count the wheels, though.

Most likely not 6...

[caume]

Originally Posted by messer5740

Most likely not 6...

To counter that argument, look at like 90% of the robotics this year, 6WD. This is just a fancy 6WD if you think about it

[messer5740]

Originally Posted by caume

To counter that argument, look at like 90% of the robotics this year, 6WD. This is just a fancy 6WD if you think about it

True true didn't think about our own robot

[ThaddeusMaximus]

Originally Posted by caume

To counter that argument, look at like 90% of the robotics this year, 6WD. This is just a fancy 6WD if you think about it

6 wheels? yep. fancy? You betcha. Same thing? Heavens no.

6wd gives you maximum pushing force (for both motor and traction) in the direction of orientation. Omniwheels currently available are less grippy than solid wheels currently available, and having 2/3s of your wheels basically inactive when in a straight line reduces motor power. These are not perks...

Not to mention the normal force on any set of wheels is half of that in a kiwi. I'd think for this reason that a kiwi would beat this in a pushing match, which would proceed to get dominated by a 6wd with good solid wheels.

[caume]

Originally Posted by ThaddeusMaximus

6 wheels? yep. fancy? You betcha. Same thing? Heavens no.

6wd gives you maximum pushing force (for both motor and traction) in the direction of orientation. Omniwheels currently available are less grippy than solid wheels currently available, and having 2/3s of your wheels basically inactive when in a straight line reduces motor power. These are not perks...

Not to mention the normal force on any set of wheels is half of that in a kiwi. I'd think for this reason that a kiwi would beat this in a pushing match, which would proceed to get dominated by a 6wd with good solid wheels.

I was mostly joking when I said it's a 6WD. Obviously, the only real similarity is the number of wheels. Where did you get the information about omnis being less grippy? I'm not doubting it at all, I just haven't been able to find info about the CoF when I've looked.

[EricH]

Originally Posted by caume

I was mostly joking when I said it's a 6WD. Obviously, the only real similarity is the number of wheels. Where did you get the information about omnis being less grippy? I'm not doubting it at all, I just haven't been able to find info about the CoF when I've looked.

0.8-0.88 for an AM 6" aluminum omni (AM site)
A 6" "normal" wheel (rubber tread, not high grip) is 0.9 (AM site).
"HiGrip" wheels are 0.95.

That's going to be a 10%-20% increase in grippiness when using non-omni wheels instead of omniwheels.

[Jonny_Jee]

Originally Posted by messer5740

Most likely not 6...

148 had a three wheel swerve drive that year.

[Cash4587]

The programming on this would be very very tricky. Figuring out how much power to give each motor in the "Forward" direction would take some playing with and tuning because two wheels are pointed "Forward" and the other four are angled.

Although this is a cool idea and looks interesting it probably is not very practical. In most cases it would make the most sense to just do a 3 wheel kiwi or an H-Drive. For that matter, even a swerve would probably make more sense.