Rhino Treads and Bumpers

[team3949robotic]

Anyone know how to attach the bumpers to the rhino treads?

[MrForbes]

The obvious answer (for me) is to build a plywood box around the treads, and attach the bumpers to that. But I’m sure there’s a more difficult way to do it.

[eedoga]

We are currently hoping to use this system. Looking at the cad files there are holes along the top edge of the outside plate. We plan to fabricate L-brackets facing out, and then to use that to mount a Large Rectangular U shaped rail on which the bumpers will be mounted.

I will try to post CADD files or diagrams later today.

Hope this helps,

Edoga

[Sperkowsky]

All I can tell you is that it is very difficult to make a solution without hurting performance. I tried to do it during a CAD competition and gave up after an an hour or so of playing around. I was able to make legal ones for the sides but the corners posed a lot of problems.

[AndyBare]

My suggestion is building the skeleton of your robot from 80-20 Aluminum. It works wonderfully with bracketing systems, and holds up well through contact. This picture kind of expresses what I’m trying to say. Bumpers and brackets are red. The diagram shows you how they brackets and screws connect. The rhino tread is blue. 80-20 and aluminum parts of rhino treads are white. Triangle brackets are gray. This isn’t a CAD, but hopefully you can still find it useful, or at least get some ideas for what direction to head into with this.

The note of dimensions is to express that the 80-20 T’s would support the L-bracket far enough over the treads so that the bumpers would cover the frame perimeter.

You can totally do something like this and incorporate different types of support beams into a non 80-20 framed robot (may even be lighter that way)

[Sperkowsky]

@AndyBare

My suggestion is building the skeleton of your robot from 80-20 Aluminum. It works wonderfully with bracketing systems, and holds up well through contact. This picture kind of expresses what I’m trying to say. Bumpers and brackets are red. The diagram shows you how they brackets and screws connect. The rhino tread is blue. 80-20 and aluminum parts of rhino treads are white. Triangle brackets are gray. This isn’t a CAD, but hopefully you can still find it useful, or at least get some ideas for what direction to head into with this.

The note of dimensions is to express that the 80-20 T’s would support the L-bracket far enough over the treads so that the bumpers would cover the frame perimeter.

You can totally do something like this and incorporate different types of support beams into a non 80-20 framed robot (may even be lighter that way)

I do not see a picture

[AndyBare]

@Sperkowsky

I do not see a picture

Yeah, my bad. File was too large. Let me know if this helps in any way.

[3949_Co-Captain]

Hi Andy, we like your design for a frame for the rhino treads but the only problem from your design that we notice is that the bumpers would cover the rhino incline causing the robot when going up to the rock wall or rough terrain to not really have any effect as the bumper would cause a conflict. If you have any other ideas or something that you want to add on we appreciate that a lot, and great picture btw!

[AndyBare]

@3949 Co-Captain

Hi Andy, we like your design for a frame for the rhino treads but the only problem from your design that we notice is that the bumpers would cover the rhino incline causing the robot when going up to the rock wall or rough terrain to not really have any effect as the bumper would cause a conflict. If you have any other ideas or something that you want to add on we appreciate that a lot, and great picture btw!

Thanks! I appreciate it! I’m doing some calculations real quick. Let you know what I find!

Edit:
So I’ve come up with a couple of calculations/measurements which I hope you find reassuring.

a. The bumper zone is 4" to 12". Since bumpers are required to be 4 inches tall, The highest you can put them is 8". That’s important, because it’s probably what you’d want to do.
b. defense platforms are 3"tall - just the platforms alone.
b1. the moat would add an additional 1.5" making the moat a 4.5" obstacle.
b2. the ramparts would add an additional 3.09198" (found by angle angle side trig)- if you were going over them backwards. This would make a roughly 6" obstacle [again, backwards].
b3. The rock wall would add an extra 4.5" making it a 7.5" obstacle.
b4. The rough terrain would add an extra 3" in any given location upon it, as the largest tubing used is 3", making it a maximum 6" obstacle.
b5. The cheval de frise would add an additional 4.8125" making it a 7.8125" Obstacle.

I saved the cheval for last for two reasons. First is to explain that the bridges would be a 7.8125" obstacle if they were flat. If tipped completely in the opposite direction, they would become a 12.8125" obstacle. If tipped completely towards you, they would simply be a 3" obstacle because once you’re driving up the platform ramp, you’re bot will already be angled over them.
That’s the second reason I saved them. They help describe the case of the rhino tread system, or any sloped system. When a slope meets another slope in the same direction, they are added together. For instance, say the slope of the front of the treads is at a 40 degree angle. As you drive onto a ramp with a slope of 10 degrees, your 40 degree angle becomes in relation to the 10 degree angle, and thus you now have a 50 degree angle off of the flat ground.
That being said, all of the “maximum defense heights” as listed above actually become a little less tall when in respect to the new angle achieved by driving onto any defense ramp.

This angles aspect is described a little better in another thread. If I can find it ill edit the link in Here: http://www.chiefdelphi.com/media/photos/42631 - it’s posted for a seperate reason, but stands to show for what I was trying to explain

Lastly, I was playing with the rhino tread in solidworks today and found out some important numbers… which I will go rediscover now so that I may share them with you.

1. If you format your rhino treads as AndyMark has formatted theirs in their step file, you will have a 34 degree angle of elevation.
2. The center of the topmost wheel under this configuration sits at 7.64" off the ground.
3. Because the center of the circle is at 7.64," you don’t gain anything by contacting a surface anywhere higher on the tread than 7.64".
4. This is also good because it leaves you 4" for your bumpers to be in the bumper zone without affecting the contact of the treads, and even gives you a little bit of room to play with (your measurements probably won’t match the CAD files’.) - you may even want to play around with different angles, and see what is most comfortable with the belting.

[mbshark]

@eedoga

I will try to post CADD files or diagrams later today.

Would love to see CAD images or some STEP files.

@3949 Co-Captain

we notice … that the bumpers would cover the rhino incline causing the robot when going up to the rock wall or rough terrain to not really have any effect as the bumper would cause a conflict.

If the bumpers are set at the maximum height, they will cover around 2"-4" of the rhino tread keeping the remaining 7.5"-5.5" uncovered. As the rock wall is only 4.5", I believe that this will be a non-issue.

Also thanks for the drawing AndyBare!

[HolyHacker335]

We would love to use this system if Andymark would keep them in stock! :mad: Grrr… Needless, here are a couple of things to remember: the bumpers don’t have to be horizontal. And about the OUTER DEFENSE platforms elevations, the 2016 Field Components page 34 has the ramps at 2", but the carrier at 2.88". Kinda confusing. I built our wooden one’s to 2.5".

[Andy_Baker]

@team3949robotic

Anyone know how to attach the bumpers to the rhino treads?

We are working on a simple solution for this. Parts are in production now and we plan on having the product page up soon and these Rhino bumper brackets available by 1/25.

@HolyHacker335

We would love to use this system if Andymark would keep them in stock! :mad: Grrr… Needless, here are a couple of things to remember: the bumpers don’t have to be horizontal. And about the OUTER DEFENSE platforms elevations, the 2016 Field Components page 34 has the ramps at 2", but the carrier at 2.88". Kinda confusing. I built our wooden one’s to 2.5".

We hope to have the Rhino Track Drive module back in stock and/or available to order by 1/25.

Sincerely,
Andy Baker

[anon31892661]

@AndyBare

Thanks! I appreciate it! I’m doing some calculations real quick. Let you know what I find!

Edit:
So I’ve come up with a couple of calculations/measurements which I hope you find reassuring.

a. The bumper zone is 4" to 12". Since bumpers are required to be 4 inches tall, The highest you can put them is 8". That’s important, because it’s probably what you’d want to do.
b. defense platforms are 3"tall - just the platforms alone.
b1. the moat would add an additional 1.5" making the moat a 4.5" obstacle.
b2. the ramparts would add an additional 3.09198" (found by angle angle side trig)- if you were going over them backwards. This would make a roughly 6" obstacle [again, backwards].
b3. The rock wall would add an extra 4.5" making it a 7.5" obstacle.
b4. The rough terrain would add an extra 3" in any given location upon it, as the largest tubing used is 3", making it a maximum 6" obstacle.
b5. The cheval de frise would add an additional 4.8125" making it a 7.8125" Obstacle.

I saved the cheval for last for two reasons. First is to explain that the bridges would be a 7.8125" obstacle if they were flat. If tipped completely in the opposite direction, they would become a 12.8125" obstacle. If tipped completely towards you, they would simply be a 3" obstacle because once you’re driving up the platform ramp, you’re bot will already be angled over them.
That’s the second reason I saved them. They help describe the case of the rhino tread system, or any sloped system. When a slope meets another slope in the same direction, they are added together. For instance, say the slope of the front of the treads is at a 40 degree angle. As you drive onto a ramp with a slope of 10 degrees, your 40 degree angle becomes in relation to the 10 degree angle, and thus you now have a 50 degree angle off of the flat ground.
That being said, all of the “maximum defense heights” as listed above actually become a little less tall when in respect to the new angle achieved by driving onto any defense ramp.

This angles aspect is described a little better in another thread. If I can find it ill edit the link in Here: http://www.chiefdelphi.com/media/photos/42631 - it’s posted for a seperate reason, but stands to show for what I was trying to explain

Lastly, I was playing with the rhino tread in solidworks today and found out some important numbers… which I will go rediscover now so that I may share them with you.

1. If you format your rhino treads as AndyMark has formatted theirs in their step file, you will have a 34 degree angle of elevation.
2. The center of the topmost wheel under this configuration sits at 7.64" off the ground.
3. Because the center of the circle is at 7.64," you don’t gain anything by contacting a surface anywhere higher on the tread than 7.64".
4. This is also good because it leaves you 4" for your bumpers to be in the bumper zone without affecting the contact of the treads, and even gives you a little bit of room to play with (your measurements probably won’t match the CAD files’.) - you may even want to play around with different angles, and see what is most comfortable with the belting.

Andy I thought bumpers were 5" (Two 2.5" pool noodles) is that wrong?Are you compressing them to fit the 4" numbers on making them squished to 4" height? Or just using 2" noodles? The 4’" requirement I assume comes from the numbers correct?

[bmammen]

@Andy Baker

We are working on a simple solution for this. Parts are in production now and we plan on having the product page up soon and these Rhino bumper brackets available by 1/25.

We hope to have the Rhino Track Drive module back in stock and/or available to order by 1/25.

Sincerely,
Andy Baker

Thanks Andy! I knew AM wouldn’t let us down.

[FrankJ]

@anon31892661

Andy I thought bumpers were 5" (Two 2.5" pool noodles) is that wrong?Are you compressing them to fit the 4" numbers on making them squished to 4" height? Or just using 2" noodles? The 4’" requirement I assume comes from the numbers correct?

The plywood bumper backing is also required to be 5" tall