Need advice

[devg29]

Ok so our team has been prototyping for the entire two weeks that have gone by, and certain components of the robot are coming along, while one has not. Our design is that we're taking the totes into the robot, stacking inside the robot, and spitting them out the back (and no, we're not changing the design to stack outside the robot - it's already been decided ). So the component that we're struggling with is the one that brings the totes into the robot. We'd like not to have it on an elevator (just throwing that out there)--- we tried a pneumatic gripper but came to the conclusion that we'd need an elevator. Other than that, we've tried something that gets the tote and pivots to an angle to let the tote slide into the robot (which we pretty much ruled out because it didn't work), we're working on a design that uses wheels, and we're leaning towards that -- they'd be perpendicular to the totes as to grip them on the sides. Other than that, however, in the words of one of our mentors, we're kinda stumped. Any advice or other ideas we could try? We're really focusing on speed and the ability to do it right every time, time after time. Thanks.