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Originally Posted by GeeTwo
It looks good, but just a few questions and things to check if you haven't already:
- I understand that your speed is 16 FPS with omnis and 7 FPS with Colsons, meaning that you will run mostly on omnis and use the Colsons for pushing matches and perhaps to kick off sprints; is this correct?
- The weakest part of the side tubes will be where you cut the holes for the omnis, with the locations of the Colsons being next. Be sure when you mount bumpers that they mount to the chassis at locations other than these to avoid a bent frame.
- The push-only, spring return is one way to avoid transferring lateral forces to the piston; we have found another for our strafe wheel actuator: the open portion of our clevis pin is significantly longer than the clevis is wide, meaning that small deviations will not apply a lateral force to our piston.
- Be sure that the Colson ends of the modules, when faced with a lateral force, will contact the side walls of the tube away from the rotating axle, and preferably either between the wheels or above the green spacer/barrel nut where the tube is strongest.
- You probably realize this, but note that your CoG is well off-center. Be sure to balance the load with the battery, control board, and/or manipulator placement. The CoG should ideally be between the two strafe wheels.
- What angle of rotation of the strafe module is required for the wheels to engage the carpet? I've seen modules that went almost vertical, but these look like they only need to rotate a few degrees. One of these days I'm going to have to have a good session at a dry-erase board to figure out what the proper angles and proportions are for one of these modules.
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- Yeah, the gearbox and the sprocket reductions in the module were built so that I have those pushing match speeds. As for kick off sprints, I'm not so sure what that is, but if it is something like those drop-down omnis on 118's 2014 robot, then most likely I probably don't have that on this one.
- The holes with the omnis... I kind of see that happening. An impact directly on the bearing that occupies it might cause the tube to cave in over time
- Interesting. Honestly have nothing to say about that
- So the modules need to be somewhat the same width of the inside width of the boxtubing? I guess that makes sense. I might have solved the shaft bending, but the plates might take damage after one of those traction side impacts, so doing so would reduce the bend
- Yeah, those gearboxes would shift the CoG to that side, which I guess might make strafing some what strange. I placed them there because anywhere else would be a pain with the strafing module there, and so I can reduce how many sprockets I need. The battery, as well as additional components that would go on any FRC robot will definitely help in this situation.
- Angle of rotation, I don't have exact numbers at the moment I'm writing this, but it's really easy to calculate using trig: I think it's the inverse sine of the ratio of the distance from the driving shaft to the ground, over the distance from the driving shaft to the omni wheel shaft.
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Did you add a foot gusset to the front rails you used the barrelnut on?
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I made a custom barrel nut: take an aluminum rod, thread both ends, and drill a hole through the round face, and tap for 10-32. Screw them into place, and theoretically it should hold just fine in addition to the rivets from the belly pan
I've never heard of a foot gusset before, but to me it sounds like one that has an L shape and can mount to the side of the boxtubing. I could do that, but probably not with those modules in the way.