Rhino Treads and Bumpers

[AndyBare]

Originally Posted by 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.