Quote:
Originally Posted by notmattlythgoe
Plus the side loads on the cylinder when the module is driving are a little worrisome.
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Quote:
Originally Posted by Chris is me
By nose mounting the cylinder while also mounting it to the pivot block, you'll be putting a bending moment on the cylinder shaft when you actuate it, which isn't best practice. Other strafe modules that nose mount their cylinders just use the cylinder to push on their pivot module rather than rigidly mounting the end of the cylinder to the module in order to avoid this moment. You could also pivot mount the top of the cylinder to avoid this. .
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Look a bit closer - there will be no significant bending moment on the cylinder shaft unless the arm is practically ripped off the hinge. The pivot block pushes on a (loosely held) round bar which rides in oversize slots on the arm. So while the cylinder body is rigidly mounted to the chassis, the rod is coupled to the arm so as to only transmit force in the vertical direction.
Quote:
Originally Posted by Toa Circuit
I'd me more concerned with the sideloads the wheel produces on that hinge when driving. I could be wrong, though. With just a CIM reduced by 12 times in the toughbox onto a 3 inch radius wheel, that is potentially 100 lbf on the end of that arm, on a ~12 inch lever arm? That's a good bit of torque on that hinge. Plus, there's going to be a lot of backlash. I'd reduce the length of the arm and/or add side bearing supports to take the sideloads.
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Quote:
Originally Posted by Chris is me
I'm also concerned about the moment and side load placed on that hinge by the overhanging gearbox and wheel.
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By keeping the load carried by the wheel down to about 30 or 40 pounds, we are also keeping the strafe force down to that same value, as the static CoF of the hard plastic rollers is about 1.0 according to AndyMark. We were planning to keep a close eye on the hinge when we start driving and add some side bearing supports if needed.
If there's most of an inch or more of backlash, we'll definitely add side bearing supports. This is still much less effective backlash than a torque-actuated strafe module.