TL;DR: new telescoping arm robot. download CAD here.
Hi, all, and happy holidays. I bring you tidings of a new telescoping arm robot.
Some of you may remember that back in the summer of 2019, I threw together my very first telescoping arm design and posted it here. In the meantime, I’ve played around with new designs, and I figured that it was time to design a complete robot to show off what’s new. I’ve also used this as a chance to get familiar with the new REV control system, which is the main reason it took me so long to upload this in the first place (I was waiting the whole time for REV to drop their CAD models…).
I heard the cool kids these days were all doing single speed, single reduction gearboxes with their shiny new Falcon motors, so I joined them. It’s very convenient as a design structure and I’ll probably do it again on future designs. I also tried out the “corner horn” approach to supporting the bumpers, which at the cost of increased manufacturing effort (welding!) gives you an extra ~1.5" of wheelbase.
One of the key things that I really didn’t like about my first design was that the manipulator was ridiculously large and heavy, and for all of that weight, I didn’t even get much width to pick up balls. To solve this, the top roller has moved from the manipulator to its own, separate system, which allows it to be wider without having to figure out how to control a 30 pound manipulator. I also got aroud to adding some fancy sensors - a reflection sensor for balls and a limit switch for hatch panels. Otherwise, it’s a pretty standard 1684-esque manipulator - the arms close together to grab hatch panels from the center.
The arm is a total redesign from all of the previous telescoping arms I’ve done, with an emphasis on ease of manufacturing and assembly. This time, there’s only one unique billet part (as opposed to the 12 or so on my first telescoping arm), the arm hub. I’ve included detail views on the bearings and arm hub to show off some clever design tricks there. The bearing replaces the old billet base block with a 3D printed setup, but uses the same extended inner ring bearings as before. The pulley uses a much beefier body and mounting setup than my last few designs, and pivots around a thicker shoulder screw. On the hub, the sprocket is mounted using a set of shoulder screws to take up the side loads from pivoting, while we use the same clamping-block style as before.
I didn’t like that my first telescoping arm robot didn’t have a climber, so I’m here to correct that issue. The intake arm doubles as a climbing arm, and in the back, we have a set of legs which extend down. There’s not much else to this design (it wasn’t very original anyway) but it was a neat addition and it fit well with the rest of the robot.
I’m glad I managed to get this uploaded before Kickoff - that way, if any of you all feel like making a telescoping arm this January, you can feel free to use this design as much as you like. Thanks for reading this all the way through. If you didn’t read this all the way through, what are you doing? Go back and look at my pretty pictures. Feel free to check out the CAD here - same link as on the top of the post.
As always, questions and comments are much appreciated!