New Offseason Build

[asid61]

Congratulations on taking steps to try and revamp your team! I can't comment on the execution though.
Solidworks is a fantastic tool. I highly recommend you get as many people to learn it as possible, as cadding the robot is very handy if you want any machined parts on there (from waterjet sponsors, at least).

Powered intakes, a ramp, can stabilizer, and a fast lift is all you need to do very well at this game from what I've seen. Good choices on your design!

27:1 and what diameter pulley? Try using JVN calculator to get the speed of your lift (linear mechanism tab). If you switch to 2 cims over 1, then you can gear your lift much higher, if you want to spend the extra $.
What is webbing? Like belts?

If you would like the cad of our simple pneumatic can stabilizer, PM me. It can be made on a bandsaw/drill press.

The

[Sperkowsky]

Originally Posted by asid61

27:1 and what diameter pulley? Try using JVN calculator to get the speed of your lift (linear mechanism tab). If you switch to 2 cims over 1, then you can gear your lift much higher, if you want to spend the extra $.
What is webbing? Like belts?

If you would like the cad of our simple pneumatic can stabilizer, PM me. It can be made on a bandsaw/drill press.
The

We dont know the exact diameter for the pulley yet. What is better a larger pulley or a smaller one?

We could move to a second cim as we have dozens laying around. The issue is gear boxes. We have 2 BaneBots 27:1 gearboxes laying around with cims already on them which is a large reason we just decided to use one of them.

Webbing is fabric woven as a flat strip or tube of varying width and fibres often used in place of rope. Its mainly used for fastening loads on flat bed trucks.

Also, I would love the cad for the stabilizer you can email it to me at sperkowsky@bethpageeagles.ws or just PM it to me what ever is eaisser

[asid61]

Originally Posted by Sperkowsky

We dont know the exact diameter for the pulley yet. What is better a larger pulley or a smaller one?

We could move to a second cim as we have dozens laying around. The issue is gear boxes. We have 2 BaneBots 27:1 gearboxes laying around with cims already on them which is a large reason we just decided to use one of them.

Webbing is fabric woven as a flat strip or tube of varying width and fibres often used in place of rope. Its mainly used for fastening loads on flat bed trucks.

Also, I would love the cad for the stabilizer you can email it to me at sperkowsky@bethpageeagles.ws or just PM it to me what ever is eaisser

The ratio you use is dependent upon the pulley. For example, if you spin a shaft at 10rps (600rpm) and you have a 1" diameter pulley on it, then your speed will be:
10rps * pi * 1" diameter = 31.4"/second, because you spin it 10 times per second, and each rotation is 3.14".
With a 2" pulley, the speed doubles to 62.8"/sec. This does not account for the wrapping of the belt, dynamically enlarging the pulley.

The JVN calculator will do a lot of math for you, using it could really help you.

According to JVN calc, assuming a 200lb load (accounting for friction), and a 27:1 gearbox, a 2.5" pulley and one cim gives you a loaded elevator speed of 19"/second, or 26"/sec unloaded, and draws 59 amps loaded. I assume you're not using a brake on the elevator, so the cim also has to hold the load up. If you use 2 cims, each one only draws 31 amps, which might be ok (not sure on this). Remember that your belting will add diameter, so going with a smaller 1.5" pulley or something might have to be done.
I don't know if either of those situations are permissible for cims to hold up under the constant load of suspending the stack.

That kind of belting will probably work fine strength-wise, but check that. The diameter increasing business issue is not ideal, but using a larger pulley will mean that the diameter will increase less %-wise per rotation.

Decreasing toolpaths will really help, especially for a machine like a waterjet. Using less heavy lightening patterns, like 192's 2014 gearbox, instead of heavy lightening patterns, like 254's gearboxes, will greatly help this. 192 went with 3/16" plate IIRC instead of 1/4", so they only paid a small price in weight.

[DaveL]

Good to see you are taking proactive steps to improve!

We estimated the maximum amount of weight we were going to lift and then decided how fast we wanted to lift that weight. I think we ended up with a 16:1 transmission with 1 CIM. To insure the transmission had enough strength to handle this load we went with a BaneBots P80 transmission. http://www.banebots.com/category/P80_CIM_STOCK.html

We also used #25 chain so we could pull the elevator down as we were concerned with the elevator getting jammed.

A nearby team picked a 12.75:1 drive transmission from AndyMark and used 2 CIM motors. If you have 2 single CIM transmissions, you might be able to use both to share the load.
Vex has a nice lookup table to compare ratio to breaking output force.
http://content.vexrobotics.com/vexpr...s-20150106.pdf

Either way you can use bungee cord or surgical tubing to counter balance the weight.

From the drawing, it was hard for me to see how the structure was going to transfer the weight from the middle of the arm to the elevator. Most teams used some angle (diagonal) support instead of relying on the strength of the joint.

For more ideas; find the top teams and go to their website to review their bot pictures or find the top local teams and go visit them.

[Sperkowsky]

Originally Posted by DaveL

Good to see you are taking proactive steps to improve!

We estimated the maximum amount of weight we were going to lift and then decided how fast we wanted to lift that weight. I think we ended up with a 16:1 transmission with 1 CIM. To insure the transmission had enough strength to handle this load we went with a BaneBots P80 transmission. http://www.banebots.com/category/P80_CIM_STOCK.html

We also used #25 chain so we could pull the elevator down as we were concerned with the elevator getting jammed.

A nearby team picked a 12.75:1 drive transmission from AndyMark and used 2 CIM motors. If you have 2 single CIM transmissions, you might be able to use both to share the load.
Vex has a nice lookup table to compare ratio to breaking output force.
http://content.vexrobotics.com/vexpr...s-20150106.pdf

Either way you can use bungee cord or surgical tubing to counter balance the weight.

From the drawing, it was hard for me to see how the structure was going to transfer the weight from the middle of the arm to the elevator. Most teams used some angle (diagonal) support instead of relying on the strength of the joint.

For more ideas; find the top teams and go to their website to review their bot pictures or find the top local teams and go visit them.

We are using the Banebots p80 transmission as well just the 27:! version.

Looking at other teams designs I decided the diagonal support wasn't needed and just useless weight. Most of the top teams used dual track elevators but looking at teams like 696 it doesn't seem necessary.